A treatise on metalliferous minerals and mining

Davies, D. C. (David Christopher) · 1901 · Historical

A treatise on metalliferous minerals and mining by Davies, D. C. (David Christopher) (1901). Full text and reference in the Mountain Man Mining Library.

Public-domain full text preserved in the Mountain Man Mining Library. Original source: archive.org.

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Metalliferous Minerals And Mining

LONDON : rniNTED DV

erOTTISWOODR AND CO., NSW-STRRBT SQUARE

A Treatise On

Metalliferous Minerals

And Mining

dT F.G.S.

Mining Engineer

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Aetonlr enition, ttbUa

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London Crosby Lockwood And Co.

7 STATIOKERff-HALL COURT, LUDGATE HILL

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Preface

To

The Second Edition.

The necessity for a second edition of this book has enabled me to make several corrections and additions which will help towards its exactitude and completeness. I am pleased that these do not affect the truth of the general principles and inferences laid down or deduced in the book. Time will show, I think, that these principles and inferences are founded upon a true reading of world-wide geological phenomena, and are consequently in harmony with actual mining experience.

For the most part the book has been very favourably received by the press, and my teyivrs will see that I have to some extent availed myself of their various suggestions and, in most cases, fair criticism.

The design of the book is stated in the Preface to the first edition, and it does not aim at anything beyond that purpose.

vi PREFACE.

It simply seeks to set forth for ordinary English readers, the substance of our knowledge on Metalliferous Minerals and Mining.

If it fulfils this purpose, it will achieve what I desire for it — a permanently useful place in English mining literature.

D. C. Davies.

4

Preface

To

The First Edition.

This book is designed to describe, in a concise and systematic manner, the conditions under which metals and metallic ores are found in the different countries of the world.

It is hoped that such a description will serve, first, to explain to some extent the origin of deposits of metalliferous minerals ; and, secondly, by defining the zones occupied by the various metallic ores, to lessen somewhat the amount of imsuccessful search for them.

My hope is that by the data given, together with the figures, quantities, and results contained in the book, the commercial conditions of mining success may be better defined

The books referred to in the following pages show that there is no lack of mining literature, much of which is of a high order. Still, other persons may have felt, with myself, the want of a book covering the ground and fUfilling the purpose and plan of this volmne. My endeavour in writing it has been to illustrate great principles by a sufficiency of representative details, and to refer the reader to sources where additional

viii PREFACE.

illnstntion, as well as the enumeration of the minrter details of mining, may be found.

The explanations of scientific and of mining terms which are appended will, I hope, facilitate to ordinary readers the comprehension of the whole of the matters treated of.

The illustrations have been prepared by my son, Mr. £. Henry Davies, and my thanks are due to him for his willing and efficient co-operation.

My sincere wish is that this book may prove of real service to all those who are engaged in a profession which is as honourable when honestly followed as it is arduous and difficult in practice.

D. C. Davies.

Ebnal Lodge, Gobowbn, Oswistet.

Contents.

Chapter I.

Materials Of Which The Earth Is Made

Pacb

Lut of Simple Elements — How Distinguished and Characterised — Metalliferous Minerals selected for description in this book — Table of Strata — General Geological Position of Metallic Minerals — Great Parallel Mountain Chains of the World . . . . i

Chapter Ii.

Classification Of The Deposits Of Metalliferous Minerals.

Lodes — Description and Origin — Lodes of Displacement — Gash Veins — Horses — Gaunter Lodes — Displacement of Lodes — Dykes— £1 van Courses — Considerations affecting the Dip of Lodes — Eaithy Minerals of Lodes — Gossan Peachy, Caple, Pryan, Quartz, Sparry, Flucan, and Grouan Lodes 8

Chapter Iil

Metallic Contents Of Lodes,

Affected by Nature of Strata — Modes of Occurrence — Origin and " Derivation — Infiltration — Condensation — Sublimation — Causes affecting the Particular and Local Deposition of . I7

Contents.

Chapter Iv.

Second, Third, And Fourth Classes Of

Mineral Deposits

rAGm Stratified Mineral Deposits — Irregularly Stratified Deposits — Contact Depositt — Segregated and Crystalline Masses of Ore — Flats — Irrlar Deposits — Pockets — Contact Deposits — Network of Veins — Disseminated Ores — Superficial Deposits 25

Chapter V. Gold.

Characteristics and Modes of Occurrence— Driftel Gold— Nuggets — Gold in Lodes and Veins — Alluvial Deposits of the Ural Mountidns — Mining in the Solid Rock — Austro-Hungary — Mines of the Banat — Gold in Central Europe— Sands of the Rhine— Lodes and Alluvium of France, Spain and Portugal, and Italy . . 32

CHAPTER VI. GOLD —continued.

Gold Deposits of Gogofau— The Dolgelly District — Scotland- Ireland — In situ and in Alluvial Deposits in County Wicklow . 40

Chapter Vil

GOLD—<mtimted.

Eastern North America — New England States — Virginia — Nova Scotia — New Brunswick — Lake Superior — California and the Western States— Alluvial Deposits — Gold-bearing Strata— Statistics . . 45

CHAPTER VIIL COLDcontimud.

Central America — Venezuela— Brazil — History of Gold Mining m Brazil — Mines of Gongo Soco and St. John del Key — Analysis — Other Countries of South America 55

Contents. Xi

Chapter Ix.

Pacb

AustnlasiA — History of the Discovery of Gold — New South Wales — Victoria — Tasmania — Queensland — Productiveness of Reefs in Depth — Structure of Ree&— Gold Drifts — Proportion of Gold in Drifts 63

Chapter X.

GOLD-conHmud,

New Zealand — History — Gold in sUu — Gold in Drifts — Africa— Gold Fields of Leydenberg — India — Philippine Islands— Aruba Island — Concluding Remarks 75

Chapter Xl Silver.

jeneral Characteristics — Its Ores — Silver in Russia, Austria, Bohemia, and Saxony — Description of the Mines of the Ezzgebiige — Hanover and Brunswick — Nassau— France, Spain, Norway, and Great Britain 81

Chapter Xii.

SILVER-coHtmued.

Silver Ores of North-Eastem America — North- Western America — The Comstock Lode and Ruby Hill, Nevada— The Emma Mme, Utah — Similarity of the Deposits Northwards and Southwards . 94

Chapter Xiil

SIL VERcmUintied.

Silver ia Arizcma — Mexico— The South American ContinentPeru — Bolivia — Chili — Western Side of Sooth America geiallyConeluding Observations and Dednetioiia 107

Xll CONTENTS

Chapter Xiv. Copper.

*Agb

Gcnenl Remarks — Native Copper— The Ores of Copper . 1 14

CHAPTER XV. COPPER-onHmud,

The Ores of Copper in Russia — Ural Moontains — Westeni Side of the Ural Mountains — Caucasus — South Africa — The Cape— Algiers — Spain — Italy — Austria — Germany : Prussia — Norway — Sweden and France 118

CHAPTER XVI. COPPER— contiuued,

British Isles — Cornwall — Geological Structure and Characteristics of the Mining Districts of the County— Special Features of Lodes — Dolcoath Mine — History of Copper Mining in the West of England 1 25

CHAPTER XVII. COPPER— mti$ned.

Cupreous Sandstones of Cheshire and Salop— The Limestones of Salop and North Wales— The Parys Mines of Anglesea— The Copper Turf of Merioneth — Copper in Carnarvonshire and Cardiganiire — North- West of England, and County Wicklow in Ireland 136

Chapter Xviil

COPPER— continued.

Copper Deposits of North-Eutem AsKrica — Nova Scotia to Carolina — Mississippi Valley, Wisconsin — Lake Superin — Canada . . 14S

Chapter Xix.

COPPER— continued.

Western North America — Colorado, Montana, Nevada, and Arizona — Wyoming — Cuba — Jamaica — South America — Venezuela and Chili — Australasia — North and South Australia — York Peninsula — Flinders Range — Victoria — New South Wales — Japan — Inferences and Concluding Remarks . . . . , .156

Contents. Xju

Chapter Xx. Tsn.

Pace

General Description — Modes of Occurrence — Alluvial Mining in Banca — In the Malay Peninsula— Tin Ore Deposits of Bohemia and Saxony — France and Sweden 164

Chapter Xxi.

TIN-conimued,

Tin in the British Isles — Cornwall — Importance and Antiquity of the Industry— Brief History of Tin Mining in the County— The Great Flat Lode— Cligga Point— Remarks on the Depths of Mines, and on the Particular Structure of the Tin Lodes of Cornwall . .171

Chapter Xxii.

TIN-continued,

Alluvial Tin Deposits of Cornwall—- Tm in Bolivia, Queensland, New South Wales, Victoria, and Tasmania — General Deductions and Concluding Observations 182

Chapter Xxiii. Lead,

Native— Ores of Lead — Lead Ores of Austro-Hungary— Banat — Carinthian Alps — Bleibeig— Germany — Erzgebirge— Hartz— Clausthal and Zeller— Nassau — Rhenish Ivinces— Spain — Brief History — Andahisia — Sierra de Almagrera — Linares — Hoxnachos — France — Pontgibaod-Poullaouen — Bretagne — Belgium . . . 1S9

Chapter Xxiv.

LEAD—continued.

Lead Mines of the British Isles — Statistics — Lead Mines of Shropshire — Montgomeryshire — The Van — Cardiganshire — Brief History of the Lead Mines of Cardiganshire, and Modes of Occurrence of the Ores 200

Xiv Contents,

r CHAPTER XXV,

4Lead Mines of CarnarvonsUze, of the Isle of Man, of Cornwall — West Chiverton, of Devoo, of the North of England — Northnmberlandt Durham, Westmoreland, and Cumberland, of Yorkshire, of Derbyshire — Lead Mines of the Lfanestones of Flintshirek and Denbighshire — Lead Mines of Ireland . '3

Chapter Xxvi.

Lead Mines of North-Eastem America— Canada — New England States — Wisconsin, Illinois, and' Iowa — Carbonate of Lead in Colorado — Summary and Deductions S33

Chapter Xxvil

Zinc, .

Genend Remarks — Ores of Ziiic— Zinc Ores of Siberia, Hungary, Silena, .Saidinia, Algeria, Belgium, Britain and Ireland, X America, Eastern America — New Jersey— Zinc Ores of the Lead Region of Wisconsin, of the Western States — Concluding Remarks 241

Chapter Xxviii. Iron.

Wide Distribution — Native Iron — Ores of Iron — Stratigiaphical Groups of Iron Ores — Iron Ore Deposits of India — Anstria — Germany— Nassau — Other German States — Sweden and Norway Belgium — France— Spain— Algeria 250

Chapter Xxix.

IRON—€ontinued. ' '

Iron Ore Deposits of the British Isles — Cornwall — Devon — Forest of Dean — Lancadure and Cumberland — Iron Ores of the Colmeasures— DivisicNis of the Coal-measures, and Iron Ores of each Division — Iron Ores of the Liaasic and Oolitic Stiata — Of Yorkshire, Lincolnshire, and Northamptonshire — North*East of Irefaid 262

Contents. Xv

Chapter Xxx.

Pack

Ores of the Dominion of Canada— Nova Scotia—- The United States — Eastern States— Missouri — Michigan and Lake Superior — Of Australasia— General Deductions , , . , . ,275

Chapter Xxxi. Various Metals.

Mercury Ores and Distribution— Bismuth— Nickel— Platinum — Iridium— Palladium and Tellurium , 281

Chapter Xxxii. On The Discovery And Proving Of Mines,

Old Superstitions — The Strata containing Metalliferous Minerals — The Stratigraphical Zones of the different Minerals — Discovery of Mines apparenUy accidental not really so— Surface Indications — Shoding — Explorers — Prospecting — Contents and Character of Lodes — Proving by Trenches, Small Shafts, Adits, Shafts and Levels along Lode, Sumps 292

Chapter Xxxiii. On The Working Of Metalliferous Mines.

Shafts — Vertical — Diagonal — Arrangement — Winding Compartment — Pumping Compartment — Ladders — Man-Engines — Cages, Guides — Adit Levels — Working Levels — Winzes — Stopes — Timbering— Ironstone Mining in Coal-measures— In Jurassic Strata . 303

Chapter Xxxiv.

ON THE WORKING OF METALLIFEROUS MpIES

amtinued.

Timber— Ventilation— Temperature, Fans— Old Methods of BJdng Rocks down— Drilling— Single Hand — Double Hand — Undeild — Rock Drilling Machines — History — Classes of Drills— Prindjles of Construction — Detailed Construction — Air CompressorST- Receivers, Pipes — Hand Boring Machines— Jordan's — Victor's— Faber's % . 318

XVi CONTENTS. '

Chapter Xxxv.

On The Working Of Metalliferous Mines-

Paob

{jEplosiyes — Gunpowder — Compositions of Various KindsPrinciple of Explosion from Nitro-Glycerine — Dynamite— Lithofracteur — Tonite — Gun-cotton — Patent Gunpowder — Explosion by Detonators— Saving that could be Effected often Prevented by Miners — Plan adopted in American Mines — Danger — Firing by means of Electricity 331

Chapter Xxxvi.

On The Working Of Metalliferous Mines—

continued.

Drainage and Pumping — Ancient Methods— Barrels — Hand Whims —Horse Whims — Water Wheels— Newcomen's Engine— Watt's Engine — Saving effected in Fuel — Register of Duty, 1812, 1844, igyg — Tables of Work done — Improvements resulting in Increase of Duty in Boilers, Engines, Shalt Appliances — General Description of Pumping Arrangements in a Shaft — Other Pumps — Hydtaulic-po wer — Windmills — Great Tunnels for Drainage — Blackett, Halkyn, Redruth, Kit Hill, Ernst August, Rothshonbergen, Emperor Joseph, Comstock 339

Chapter Xxxvii. On The Dressing Of Metaluc Ores.

Picking and Sorting — Crushing with Hammers — Spalling — Orebreaking Machines — Blake's and others — Stamping and Stamps — Old Cornish Stamps — Improved Stamps — Work done by them — Work done by American and Australian Stamps — Recently Invented Stamps — Patterson's Elephant Ore Stamp — Sholl's Pneumatic Stamp— Husband's Stamp— Harris's Annular Stamp Head — Cox's Stamping Machine 350

Chapter Xxxviii.

ON THE DRESSING OF METALLIC ORES—conHnued,

Jigging — The Different Specific Gravity of Different Mineral Substances— A Reason why they can be Mechanically Separated — Table of Rates at which various substances £r11 through Water-

CONTENTS. XVll

Pagb

Introduction of Hand Jigging — Mechanical Jigging — Principle of Jigging — Jigs with Movable Sieves — Jigs with Fixed Sieves — Selfacting Continuous Ore Dressing Machinery — Green's — Rotating Jig or Buddie — Buddies — Ordinary Round Buddies — Slime Pits — Tozing — Machinery for Retreatment of Ores — Dressing Tin, Copper, Silver, Gold — Methods pursued in Brazil and in Victoria . 363

Chapter Xxxix. Hydraulic Gold Mining,

The Pan— Cradle— Long Tom— Broad Tom— Artificial Sluice- Natural Sluice— Top Unproductive Drift— Mining — Hydraulic Excavation— Runs— Cleaning up, &c 375

Chapter Xl.

Sundry Particulars Of Work And Costs.

Gold — Quartz Mining— Alluvial and Hydraulic Mining — Tables of Particulars. — Silver — Altai Mountains — Dry Ore Concentration — Mode of Treatment in Meadco— Copper — Cape Mines — Algerian Mines — Parys Mountain Mines — Lake Superior Copper Mines — Tin — Costs of Work in Cornwall — Percentage of Black Tin to Ore— Of Black to Metallic Tin— Cost of Dressing— Cost of Prepared Ore per Ton — Banca, Australia, Red River, Cornwall, Stream Tin Workings — Lead— Various Costs— Zinc — Various Costs — Iron — Various Costs— Deepest Mine Shafts in the World . 3S2

Chapter Xli. General Considerations,

Large Proportion of Unprofitable Mines — Unsuccessful British Mining in America — Causes — Want of Knowledge of First Principles — Insufficient Capital — Excess of Unproductive Capital — Exorbitant Prices Paid for Mines — Expensive General Management — Ditto Local Management — Mine Gambling — Rules to Regulate the Sale and Purchase of Mines — Possible Reduction in the Cost of Working Mines — Remedies — Possible Future of Successful Mining — Concluding Observations 397

Glossary of Words and Terms used in Mining, and of Scientific Words used in this Book 405

Indsx 433

List Of Illustrations.

Pacb

1. Lodes in the Strata of Flintshire, North Wales 9

2. Slastiation of the various relative positions of lode and strata . . 10

3. niostration of lode on a line of displacement of strata . . 10

4. Section of lode at the Neuglack Mine, Freiberg, showing hones

5. Illustration of ' cannter ' or contra lodes 12

6. Section of Old Wheal Agnes Tin Mine, Cornwall, showing dis-

placement of lodes by faults 13

7. Illnstiation of horizontal displacement of lode . -13

8. Section of lode at Christbescherung Mine, near Freiberg, showing

rounded masses of rock and ore 18

9. Section of a sparry lode near Freiberg 19

10. Section of the Drei Prinzen Lode, Freiberg 20

11. Section of lode at Alte Hofihung Gottes Mine, near Freiberg . fli

12. Section of another lode at the same mine, showing ore and vein

stuff in layers 22

13. Ulustration of a crack following line of weakest resistance . . 27

14. Section of lode at Alston Moor, showing changes of dip and pro-

ductiveness of lode 28

15* Section showing the two conditions under which gold is usually

16. Section of gold diggings, south of Miask, in the Ural Mountains 37

1 7. Section through the Oravicsa group of mines. South- West Hungary 37

18. Ideal section across the Appalachian chain of mountains . . 45

19. Section of gold strata at Woodville, Virginia 46

20. General section, from the Sierra Nevada into California . '52

21. Section of gold strata near Congo Soco, Brazil . . . . 58

22. Section ofNthe Bahu portion of gold lode at St. John del Rey

23. Section of strata through the gold districts of Victoria . . . 65

24. Anxiferous gold reef near Ballarat, with method of working . 66

List Of Illustrations. Xix

Pig. Page

25. Section of the New Soath Wales Carboniferous strata . 67

26. Illustration of gold drift at the base of the Coal-measures, New

South Wales 68

27. Illustration of the intimate structure of a gold quartz reef in New

South Wales ... 69

28. Another illustration of the same . . . . . . . 69

20. 'i Sections of the older gold drifts of Victoria, with superincumbent

drifts and basalts 7I

31./

32. Horizontal section of the older gold drift of Victoria, showing

position of leads . 72

33. Section of newer gold drift on Macquarie River, New South

Wales 73

34. Section across the Province of Otago, New Zealand . 75

35. Section through the Leydenberg Gold Field, South Africa . . 77

36. Cross section at Simon Judas Mine, Banat, South-East Hungary 84

37. Diagram section across the Erzgebirge Mountains . . .86

38. Diagram of the Silver Fahlbands, Konisberg, Norway . . 91

39. Section across the Comstock lode and its enclosing strata . . 96 4a Longitudinal section of the Comstock lode, showing the mine

41. Illustration of the structure of Ruby Hill, Nevada . . . 100

42. Transverse section of the Great Ore Chamber, Emma Mine . .104

43. Argentiferous strata, Santa Rosa Mine, Peru 108

44. Section of strata and description of the principal lode at Chanara-

dllo, near Copiapo, Chili ill

45. Section of pyrites deposit, Buitron Mine, Huelva, Spain . .120

46. Diagram showing the mode of occurrence of copper ore, Fahlnn,

Sweden 123

47. Section of strata from Boscastle to Pencarrow Point, Cornwall . 126

49. - Detailed sections of copper lodes, Cornwall 132

50.)

51. Old section of workings on the Gaunter lode, Ddooath Mine,

Cornwall 133

52* Section of copper shale bed in limestone, Shropshire . . . 137

53. Section across strata and copper deposits at the Parys Mine,

Anglesea 140

54. Section of workings on the Great Open Cast, Parys Mine,

Anglesea 141

55. Section of workings on the North Discovery lode, Parys Mine,

Anglesea 142

Xx List Of Illustrations.

Fig. Pa6K

5 5 A. Illustration of the copper and pyrites deposits, Old Ballymur

tagh Mine, Ireland 146

56. Section of lode at Tigroney Mines, Ovoca, Wicklow, Ireland . 146

57. Section of the cupriferous bed at the Dolly Hide Mine, Mary

land 148

58. Section of strata in the Lake Superior Copper Region . .150

59. Section at Waterbury Copper Iine, Lake Superior . . . 151

60. Section at Eureka Mine, Lake Superior . . . . 152

61. Section of workings at the Cliff Mine, Lake Superior . . . 153

62. Section of strata in the Ontonagon Copper District, Lake

Superior 154

63. Section of copper deposits, near Copiapo, Chili . . . . 158

64. Section of the alluvial tin deposits, Banca . . . .165

65. Section of strata with tin ore, Zinwald, Bohemia . . . . 166

66. Section of tin stockwerk, Altenberg, Saxony . . . .167

67. Section of the tin stockwerk of Geyer, Saxony . . . 168

68. Illustration of the intimate structure of the stockwerk of Geyer . 169

69. Plans and sections of tin mines on the Great Flat lode of Red

ruth, Cornwall Pla

70. Section of tin lode at Wheal Uny, Cornwall . . . 174 7J. Section of tin lode at West Wheal Basset, Cornwall . . . 174

' [Sections of tin lode at South Condurrow, Cornwall . . I75

74. Plan of lode at East Wheal Lovell Mine, Redruth, Cornwall . 177

75. Section of lode imbedded in strata, South of Park Mines, Com

wall

76. Section of granite, with veins of tin ore, Clia Point, Cornwall 179

77. Enlarged view of veins in granite, Cligga Point, Cornwall . . 179

78. Section of lode at Old Hewas Mine, Cornwall . . . .180

79. Section of the Rammelsbeig Lead Ore Deposit, Hartz, Germany 194

80. Section of strata in the Shelve Mining District, Shropshire . . 201

81. Section of strata, with courses of ore, at Snailbeach Mine,

Shropshire 203

82. Section of strata at Llangynog, North Wales . . . . 204

83. Cross section of the lode and workings at the Van Mine, Mont

gomeryshire . 206

84. Section in Cardiganshire, showing probable thicknesses of

mineral zones . 209

85. Section of the Llanrwst Mining District, Carnarvonshire, showing

depths of several mines 213

86. Section of lode in Old Pencraig Mine, Carnarvonshire . . . 214

87. Section of West Chiverton Lead Mine, Cornwall . . .215

88. Section of lode in Wheal Mary Ann, Cornwall . . . . 217

List Of Illustrations. Xxi

Fig. Page

89. General section across the Pennine Chain, England . .219

90. Detailed section of limestone strata, North of England . . 220

91 . Cross section of Browngill Vein, Alston Moor, North of England 22 1

92. Lode in Great Limestone Vein at Cowpei's Dyke, North of

England .222

93. Piano-section of the *Low Flat,' west of the Handsome Cross

Vein, North of England 224

94. Cross section of the same, showing the 'flats' in the Great

Limestone 225

95. Section of limestone strata, Yorkshire, shovdng productive and

unproductive portion of lodes 227

96. Section of limestone in Flintshire and Denbighshire . . . 230

97. Section of strata at North Hendre Lead Mine, Mold, North

Wales 231

98. Lead lode in micaceous slate, Connecticut 234

99. Lead ore deposits in galena limestone, Wisconsin . . . 236 100. Section of lead deposit, Williams & Co*s. Mine, Wisconsin . . 237 loi. Section of lead deposit, Black's Mine, Wisconsin . . . 237

102. Section of strata in California Gulch, Colorado, showing portion

of carbonate of lead deposits 238

103. Section of strata with zinc ore deposits, between Li and

Venders 244

104. Diagram of the Vieille Montague zinc ore deposit, Aix-la-

Chapelle 245

105. Section of strata with zinc ores, near Sparta, New Jersey . 247

106. Section of Kunjamullay Iron Mountain, India . . . 254

107. Section of ironstone mine at Obemeissen, Nassau, North

Germany 256

108. Diagram of strata with iron ore, Danemora, Sweden . . . 257

109. Section of strata with iron ore, Haytor Mine, Devonshire . 263

1 10. Diagram of the ironstone pockets in the Forest of Dean . . 264

111. View of large ironstone chum. Devil's Chapel, near Bream . 265

112. Section of haematite deposit at Parkside, Cumberland . . . 266

113. Section of the Jurassic strata of England, showing the relative

position of the Yorkshire, Northamptonshire, and Lincolnshire iron ores 270

1 14. Section of Pilot Knob, Missouri 277

115. Section showing the geological position of the iron ores of Lake

Superior 278

116. Lode worked by vertical shaft 304

117. Lode worked by diagonal shaft 305

118. Internal arrangements of shaft 307

1 19. Timbering shaft in loose ground 308

xxu

List Of Illustrations.

'Ig. Pags

[20. Section of shaft with man engine . . , 309

[21. Timbering level in loose ground . . . . . 31I

[22. Timbered entrance to level , 312

[23. Stone entrance to level 312

[24. Timbered roof of narrow working level 314

[25. Timbered roof of wide working level 314

[26. View of stopes in a mine 315

[27. Plan of workings in the Clayband ironstone of Warwickshire . 316

[2S. Plan of working the Cleveland ironstone 317

[29. Section of drilling machine 324

[30. Bering machine at work 327

[31. Hand-power rock drill at work 328

[32. Section of mechanism of hand-power rock drill . . . 329

[35. Maisden's Blake's ore crusher 352

[36. Old Cornish stamping machine 354

[37. Sholl's pneumatic stamping machine, side view . . 359

[38. Sholl's pneumatic stamping machine, front view . . . 360

[39. Jigger with movable sieve . 364

[40. Jigger with fixed sieve 364

[41. Continuous ore dressing machinery — elevation . 366

[42. „ side elevation of jiggers 367

[43. „ end elevation of jiggers 368

[44. Rotating buddle or jigger 369

[45. Section of round buddle . 370

[46. Section of Silver Mill in Western America 371

[47. Slaves washing for gold and diamonds in Brazil . . . 378

[48. Modem hydraulic mining 379

A Treatise On

Metalliferous Minerals

And Mining.

Chapter I.

Materials Of Which The Earth Is Made.

List of Simple Elements — How distinguished and characterised— Metalliferous Minerals selected for description in this book — Table of Strata — General Geological Position of Metallic Minerals — Great Parallel Mountain Chains of the World.

The materials of which the Earth is made are, in their combi* nations and variations, very numerous, amounting in all to about 600 species. When, however, these \'ariations are analysed and resolved into their constituent parts, it is found that the whole of them, as far as at present known, are comprised within sixtythree simple elements, which, of course, cannot be further subdivided. The following is a list of the names of these elementary substances, together with the signs or abbreviations by which they are usually known : —

Aluminium

. Al

Carbon

Indium .

. In.

Antimony

. Sb.

Cerium .

. Ce.

Iodine .

Arsenic .

. As.

Chlorine.

Iridium

. Ir.

Barium .

. Ba.

Chromium

. Cr.

Iron

. Fe.

Beryllium

. Be.

Cobalt .

. Co.

Lanthanum

. La.

Bismuth

. Bi.

. Cu.

Lead .

. Pb.

Boron

. B.

Didymium

. D.

Lithium .

Bromine.

. Br.

Erbium .

. E.

Magnesium

. Mg.

Cadmium

. Cd.

Fluorine .

. F.

Manganese

. Mn.

Csesium .

. Cs.

Gold .

. Au.

Mercury

. Hg.

Calcium .

. Ca.

Hydrogen

. H.

Molybdenum

. Mo.

B

Metalliferous Minerals And Mining.

Nickel .

. Ni.

Rubidium

. Rb.

Thallium

Tl.

Niobium

. Nb.

Ruthenium

. Ru.

Thorium

Th.

Nitrogen

. N.

Selenium

. Se.

Tin

Sn.

Osmium .

. Os.

Silver .

. Ag.

Titanium

Ti.

Oxygen .

. O.

Silicon .

. Si.

Tungsten

W.

Palladium

. Pd.

Sodium .

. Na.

Uranium

U.

Phosphorus

. P.

Strontium

. Sr.

Vanadium

Platinum

. Pi.

Sulphur .

. S.

Yttrium .

Y.

Potassium

. K.

Tantalum

. Ta.

Zinc

Zn.

Rhodium

. Rh.

Tellurium

. Te.

Zirconium

Zr.

To which may now be added the substance named Gallium.

These elements, with their combinations, are distinguishable in a variety of ways, the principal of which may be summarised thus : —

ist By their specific gravity or their relative weight to that of an equal bulk of water. For example — a cubic foot of iron is seven times heavier than a cubic foot of water, its specific gravity is therefore described as G (or gravity) =7.

2nd. By their degrees of hardness, as compared with a given standard or gradation of substances. This gradation consists of the following substances, beginning with the softest and ending with the hardest : —

1. Talc.

2. Rock Salt.

3. Calcareous Spar.

4. Fluor Spar.

5. Apatite.

6. Adularia Felspar.

7. Rock Crystal

8. Prismatic Topaz.

9. Corundum. 10. The Diamond.

Taking copper as an example, its hardness, varying from that of rock salt to that of calcareous spar, is described as H (or hardness) 2.5 ...3.

3rd. By their appearance and by their degrees of opaqueness or transparency : thus, quartz is described as lustre vitreous inclining to resinous, transparent or translucent, sometimes almost opaque.'

4th. By their colour, and the results yielded by them when tested under the blow-pipe. These properties are described in each case in words and not by signs.

Characteristics Of Minerals. 3

5th. In the case of compound minerals, by their chemical composition, the study of which forms the basis of the science of Chemistry. A brief description of the compound minerals mentioned in the following pages, and which are not particularly described in the text, is given at the end of the book.

6th. By their tenacity, ductility, britdeness, and various fractural results. Thus gold is described as ' remarkably ductile and malleable,' and mercury as wholly volatile.'

7th. By the shapes they assume, or into which they crystallise when they have space and opportunity to do so. For it is foimd that each substance crystallises into one or two central forms, which have divergent but related variations in shape. Thus the primary form of felspar is a rhomboid, and that of quartz a six-sided prism ending in a pyramid. The science by which the shapes and internal structure assumed by minerals is studied and classified is called Crystallography, and it is a science which, from the combination of geometrical terms it employs, as well as from the almost innumerable divergences. of substances from their central forms, is difficult to master.

8th. By their taste, as acid, sweet, etc

9th. By their odour, as pungent, etc ; and

loth. By their solubility or otherwise when treated by acids.

The whole study of minerals by their characteristics is known as the science of Mineralogy, and the reader who desires to pursue the description of them further than is necessary for the purposes of this book, may consult the following works,: — Nicols' Mineralogy ; Dana's Mineralogy ; or the more modem elementary book, Rudiments of Mineralogy y by A. Ramsay, jun.*

The sixty-three elementary substances may be broadly subdivided thus : Metals, forty-eight ; Non-metals, fifteen. Of the latter, five are gases. Of the whole sixty-three, many of them are of very rare occurrence in nature, the bulk of the solid surface of the earth being made up for the most part of the five gases and the non- metallic minerals, oxygen and silicon being the preponderating substances.

' Crosby Lockwood and Co.

B 2

Metalliferous Minerals And Mining.

It is with the metallic minerals we have now chiefly to do/ and I select from among them for description in this book, on account of their utility in ordinary life, the following, which in the foregoing list are printed in capitals —

Gold

Silver

Platinum

Iridium

Palladiam

As the noble metals.

Copper

Tin

Lead

Zinc

Iron

Nickel

Mercury

Bismuth

Tellurium

As the useful metals.

J

These metalliferous minerals occur in nature in two distinct forms : — isL Native, when they are found unalloyed with other and especially non-metallic substances, and are therefore pure and ready for use. 2nd. Mineralised, or associated with other minerals, and in combination with the gases or earthy admixtures. As we shall see, the latter, except in the case of the noble metals, is the common mode of occurrence. In this state they are known as *ores,' which are still further distinguished by the prevailing ingredient of the mixture. For example, when metals are mixed chiefly with oxygen, they are called ' oxides ; ' when with the abundant mineral sulphur, ' sulphides ; ' and when with chlorine, 'chlorides ; ' all of which, with other combinations, we shall have to consider more particularly as we proceed.

The metallic minerals are of course found in the midst of the rocks, or strata, which form that part of the earth ith which we are most familiar — its surface. The following table gives a list of these strata in the order in which they lie upon each other, and of the names by which the different groups of them

Classification Of Strata.

U

Pi

Q

O

u

Co

O

U

o

N

o

Table of Strata.

PosT Pliocbnb.

Newer Pliocene.

Older Pliocene.

Miocene. , Eocene.

Lower, Middle and Upper

(Chalk. Uppjar Greensand. Lower Greensand.

Upper Middle

j Portland Oolite. 1 Kimmeridge Clay.

j Coral Rag.

' Combrash. Forest Marble. Lower . . - Bath or Great Oolite.

Stonekfield Slate. , Inferior Oolite.

(Upper Lias. Marlstone. Lower Lias.

( Rhaetic Beds.

Trias

Bunter (New Red SandstoneX

h

Brmia.N

'Upper Middle

pt:

o

ICoa IFonnation . Carboniferous or Mountain Limestone

bsvoNiAN (Old) Red Sand- Devonian Beds . stonr) j

Dark Red Sandstones and Marls.

Magnesian Limestones and Marls.

(Conglomerates, Breccias, and Red 1 Marls.

(Upper Coal Measures. Middle Coal Measures. Lower Coal Measures. Millstone Grit.

(Limestone and Shales. Carboniferous Limestone. Calcareous Sandstone.

I Upper Devonian.

Eozoic

Middle Devonian. ( Lower Devonian.

/Tilestones. I Upper Ludlow Beds. I Aymestry Limestones. / Silurian, or Upper Silu- J Lower Ludlow Beds.

rian . . . ] Wenlock and Woolhope Limestones.

I Denbigh Grits and Wenlock Shalu iTazannon Shale. vUpper Llandovery.

t Lower Llandovery. Silu- J Bala and Caradoc Beds. Llandeilo Beds. Arenig Beds.

Tremadoc Slates.

Lingula Flags.

Harlech and Llanberis Slates and

Grits. .Longmynd Rocks.

1 Fundamental Gneiss of the North West of Scotland and Laurentian Rocks of Canada.

Cambro, or Lower rian

Cambrian

'Laurentian

6 Metalliferous Minerals And Mining.

are known to geologists, according to their age, theii fossil contents, or the locality in which they have been most studied.

With the exception of the metal iron, more rarely copper, and occasionally one of the noble metals, all the metallic minerals we have to consider are found in the strata from the Permian downwards. The Laurentian, the Cambrian, the Silurian, the Devonian, and the Carboniferous being their great depositories. It follows, therefore, that it is only in those places where these great groups of strata are exposed on the surface of the earth we may expect to find metallic ores and mines.

As a fact these groups of strata make up the great mountain chains of the world ; the Laurentian or the Cambrian usually forming the central or basement mass of rock (see figs. 20, 37), and the newer groups reposing in their proper sequence on either side. This arrangement occurs with a remarkable uniformity all the world over.

Further, these great mountain chains will be found, on consulting a map of the world, to have, roughly speaking, a general direction from NE. to SW., sending out spurs and branches in other directions.

Thus, to select the principal examples, starting on the east there is the great mountain chain of the Ural, stretching from the Arctic Ocean on the north to the Caspian Sea on the south, and forming the great mineral depository of Russia. Nearer, there is the range of which the Carpathian Mountains are the southern termination, and which contains the principal mines of Hungar)' and Transylvania. Then, there is the great group of mountains that starts in Northern Germany and stretches down the promontory of Italy. This in its northern course contains the celebrated mining districts of the Hartz and Erzgebirge.

Next we have the coast line range of Norway, with its many mineral deposits, re -appearing in Bretagne. In our own country there is the Pennine chain, with the lead mines of Northumberland, Durham, York, and Derby. There is also the Western chain, with its ramifications, reaching from the Highlands of Scotland, through the Isle of Man and Wales, to

Great Mountain Chains. 7

Cornwall, re-appearing with its rich mineral deposits in the peninsula of Spain and Portugal

Crossing the Atlantic we find the Appalachian chain of mountains, which, starling in Nova Scotia, runs through the New England States, Pennsylvania and the Carolinas, re-appearing on the southern continent in the eastern metalliferous ranges of Brazil Then, without noticing for the present the parallel ridges, there is the mighty range and network of the Rocky Mountains, which extend from British Columbia, through California, Utah, Nevada, Arizona, and Mexico, and which in the southern continent is continued in the great ridges and peaks of the Andes. This vast chain of mountains is metalliferous all along its course, and is especially rich in the noble metals. It contains some cf the richest and most marvellous mineral deposits in the world.

Proceeding towards Australia we find the mountain ranges that run down New Zealand and the eastern side of Australia, together with the range on the west coast, of which as yet we know but little. Africa, India, China, and the Malay Archipelago, as far as we know, illustrate the same phenomenon.

It is on these mountains, and in the valleys and ravines by which they are traversed, as well as in the detritus which during long ages have accumulated in the hollows that furrow their sides, and in the plains that stretch along their feet, that we shall find, as we proceed with our inquiries, all the great deposits of metallic minerals in the world.

Chapter Ii.

Classification Of The Deposits Of Metalliferous Minerals,

Lodes — Description and Origin — Lodes of Displacement — Gash Veins — Horses — Gaunter Lodes — Displacement of Lodes — Dykes — Elvan Gourses— GonsideratioBS affecting the Dip of Lodes — Earthy Minerals of Lodes — Gossan, Peachy, Gaple, Pryan, Quartz, Sparry, Flucan, and Grouan Lodes.

All known deposits of metalliferous minerals may be comprised within the following classification : —

I. Lodes, comprising or subdivided into

2. Beds, comprising or subdividwl into

3. Irregulae Depo-

sits, comprising or subdivided into

4. Superficial De-

posits, comprising, or subdivided into

a. Simple fissures charged more or less with ores.

b. Fissures attendant on displacements of strata.

c. Minor gash veins, terminating in depth.

0. Stratified mineral deposits. b. Irregularly stratified mineral deposits, f. Deposits occurring at the place of contact of two dissimilar formations or groups of rocks.

d. Segregated and crystallised masses of ore. \t. Flats.

ia. Pockets.

b, Gontact deposits.

c. Network of veins, y. Disseminated ores.

Detrital gold. Stream tin. Bog-iron ore. .Gupreous deposits.

I. Lodes.

(a) Simple Fissures. — The word Mode* seems to be derived from tiie verb ' to lead/ and so has the same origin as loadstone or guiding stone. A lode in its simple form is a crack or fissurei

Simple Fissukk 9

which generally extends through the whole series of strata to an unknown depth, as shown in fig. i, which illustrates the order of strata in the mineral district of Flintshire, North Wales. The lodes pass downwards from the carboniferous limestone into the underlying Silurian strata ; but, as seen in the right-hand lode, they usually terminate upwards at the base of the coal measures, which proves them to be of older origin than this formation. The boundaries of a fissure or lode are called 'walls,' or sides, the upper side (a fig. i) being the 'hanging,' and the under side (&) being the ' heading ' side or wall.

I, Umtiro or Lower Uta, tliaJet and porphyrilic rocki. a, Wmloclr ihalB lad Denbigh piti. Upper Siiunan. 3, Cmboniferoin limmonc DeromaB beintf bMoc. 4. MLiroiKEm. 5, CcHl-niruuia. a, Haniiog iide of lode. J, HeadinE tide of lode. V V V, Vhm or lodei.

Fissures of this kind seem to have been produced by the shrinkage of the strata in the process of hardening, or of cooling down from a heated condition, just as the muddy bottom of a pool or the surface of clay land cracks when drying and hardening quickly under a hot sun.

Most fissures that are charged with metallic ores have a general east and west direction, which varies, however, about forty-five degrees on either side. Generally speaking, therefore, their direction is at right angles to the NK — SW. direction of the great mountain chains just described, and so are found to traverse the strata across, and not along their strike. A vein is a small lode. Lodes dip or incline downwards at all angles ' from the horizon, and the lode is said to ' hade ' in the direction of its dip. This inclination has been affected considerably by

ro METALLIFEROUS MINERALS AND MINING.

the nature of the strata the lodes have passed through. The 'rents' have been torn at the weest points. They are usually more perpendicular in hard rock, and sloping in shale, as seen in fig. 14, which illustrates this uneven course of the lodes of Durham and Northumberland. In many cases the strata appear to have been elevated and curved prior to the formation of the fissure, so that while it is the rule that the lode runs through or across the bedding, it not unfrequently happens that the dip of the lode and bedding coincides for some distance, as seen in Fio 5.— smowimc THivABiousRHLA- which generally illustrates the mode of the occurrence of the lodes of the Congo Soco gold mines, as more particularly described in Chapter VIII.

(i) Fissures of Displacement. — A lode of the kind just described lies in strata whose bedding is continuous and unbroken; but it ofien occurs that the beds on each side of the fissure do not correspond to each other, the beds on the lower side occupying a higher position than those on the hanging or upper side of the lode as seen in fig. 3, where the beds are supposed to be thrown up twenty-five feet to „„ , the north. The lode cc,

therefore, occupies a fissure made dining a disturbance of the strata, which has caused a displacement of the beds.

Generally speaking, great lines of displacement run north and south. They are of more recent origin than the east and

Gash Veins. Branches. Ii

west fissures, because they have cut through and displaced the latter. They are also, taken as a whole, less metalliferous than the east and west lodes.

(c) Gash Veins. — These are fissures of greater or less width at the surface, but thinning and dying out in depth, as illustrated in fig. 57, of the Dolly Hide Copper Mine in Maryland, and fig. 63, of a mine in Chili. These gash veins may be either simple surface cracks filled with mineral matter, or fragmentary portions of mineralised strata broken off and thrown up on end. The former kind are known by the vein cutting through or across the beds, the latter by the deposit coinciding with the bedding.

There is a variety of phenomena connected with the class of lodes I have thus far described that it will now be necessary to notice.

Horses and Braruhes. — Ofltimes the fissure is not

a clean crack from top to *''MViFRi'"Bic'sHow*K/"HuRSia'''M bottom, but appears as if Lodi.

the two sides had been torn ' ';Sil'Qtii.i?S?c!i?firdSiI*Jfh? left shreds and patches of

their substance in the midst of the crack. When a large mass of rock is thus left, and the lode is split into two, as shown in fig. 4, the lode is said to ' horse,' the parts of the lode seldom making up between them the full width of the main crack. We can also conceive how, after a crack had been made, portions of the sides would split off, and falling into the fissure make horses and branches. Again, the Tent in the strata would not

13 Metalliferous Minerals And Mining.

always be continuous, but the strata in paces being more cohesive than at others, there would be a number of minor cracks following the same direction, with portions of straU dividing them, as shown in fig. 4. When these ramifications were numerous, and covered a large space, we should find a mass of rock traversed by a network of veins, forming what the Gennans call a stockwerk, like that of Geyer, illustrated in figs. 67 and 68, Chapter XX. In this case a true lode of class i becomes a member of the irregular deposits, class liL

Besides the main fissure, there are usually associated with it minor veins, which enter it and cross it at all angles. Where these veins only penetrate the strata on one side, and die out at no great distance, they are nothing more than strings or

A A, lode B CauDter lods. c c, Foina of iotoMction dhuUt ridi is om.

branches. Where they decidedly cross it and form a continuous vein or lode, they are known as 'caunter,'or 'contra' lodes, as explamed in fig. 5.

In following a lode it is sometimes suddenly lost, owing to its displacement by a disturbance that has afiected the strata since its formation. Fig. 6, which gives a section of the Old Wheal Agnes Tin Mine, in Cornwall, illustrates this, aa are faults which have displaced the lode twice.

Sometimes this displacement is horizontal, instead of vertical, as there shown. Fig. 7 represents a displacement of this kind. A A is the lode, b b is the fault, and from c to c is the amount of displacement

In both cases, as might be inferred from the direction in

Elvan Dykes.

which the thrust has been, and as is always found by experience, the Jode may be recovered by turning along the obtuse angle of the fault.

Strata are often traversed at all angles by dykes or bands of harder matter, which seem for the most part to have been

Fkj. 6, — Sbction of Stsata ik th Pabish of St. Ache, Cobmwall. (Scule ; i"=3D Iwhonu.)

forced up cracks in a molten state from the interior of the earth, although they may have been formed by the precipitation and consolidation of very hard material along cracks and lines of disturbance in a similar manner to the way in which lodes

FlC. ;.— HomlOHTAL DlSTLACIHIHT OF LoH.

have been filled. These are known in Cornwall as elvan courses. Where such dykes are of subsequent origin to the lodes, they cut the latter and displace them in the way already

14 Metalliferous Minerals And Mining.

shown in figs. 6 and 7. Where they are of older date, the lodes are not interrupted, but frequently pinched and contracted. The same effect is produced as the lodes pass through beds of the same material, as seen in the case of the Chanaracillo Silver Mine, Chili, fig. 44, Chapter XIII. This last remark leads to the observation that the strata traversed by a lode are not all of* the same mineral nature. There are sandstones, limestones, slates, shales, felspars, granites, and many other varieties of rocks. They consequently 'differ in compactness, in density, in the power of conducting electricity, and in many other particulars. It is scarcely to be expected, therefore, that the amount of shrinkage and contraction would be the same in each case; and, as a matter of fact, it is not so. A lode usually maintains its average width in ordinary slaty rocks. It narrows, as I have just Observed, in its passage through porphyries and greenstones, whether occurring as dykes or beds, and it widens, and becomes more stringy and less well defined as it enters soft shale. Of these and other variations in the width and character of lodes as they pass through different kinds of strata, we shall have many examples as we proceed. The cracks would through all subsequent time form weak lines, or lines of weakest resistance in the strata, and we should expect that in subsequent disturbances of the strata they would sometimes be opened, and space be thus formed for the interposition of fresh matter, mineral or otherwise ; and the appearance of the lodes indicates that this has been so.

The fissures I have been describing have during long ages become filled with a variety of minerals. For the most part these are earthy minerals, which partake very largely of the nature of the adjoining rock. Thus, lead lodes in carboniferous strata contain in the millstone grit great quantities of chert and sandstone, and when they enter the limestone, calcareous breccia abounds. In the Cambro-Silurian slates, fragments of slate and re-cemented grains of the same are plentiful. When granite is entered, the lode is charged with its redistributed constituents, especially where the rock is of a decomposing kind.

Non-Metallic Matter Of Lodes. 1 5

Further, earthy minerals that enter into the composition of the enclosing strata are found in a selected and separate form in the lodes. Thus, in limestone the lodes are charged with carbonate of time and fluorspar ; in the clayey strata of the Silurian rocks, with baryta ; in the harder slaty rocks, that contain a large proportion of silica, quartz largely prevails, as it does also in the harder granites.

According to the prevalence of one or more earthy minerals and the combinations they form with each other, and among metallic minerals, chiefly with iron in lodes, the latter have been distinguished by different names, of which the following are the principal kinds, especially as known in Cornwall, whence a good portion of our mining nomenclature has been derived : —

Gossan Lodes, — Gossan is a cellular friable quartz containing earthy matter, and coloured pale yellow, brown, or black, according to the qusitity of iron it contains and the amount of decomposition it has undergone. The amount of decomposition also affects greatly the character of the lode. Black gossan contains the most iron, which often amounts to half the weight of the gossan, and it is hard, solid, and impervious to water. Red is of a hard, crystalline nature. Brown is most decomposed, while both red and brown are more brittle and friable than black. Each of these kinds of gossan bears a special relationship to enclosed metallic ores, as we shall see when we come to consider the metallic contents of lodes. When a fissure is chiefly filled with gossan of any kind, it is known as a gossan lode.'

Peachy Lodes, — \Vhen chlorite of a greenish colour, with a pearly lustre, and of a somewhat loose and cellular texture, fills up a fissure, it is known as a ' peachy lode.'

Caple or Capel Lodes, — When a lode is largely made up of hard felspar, that passes sometimes into a clayey limestone, it is called a capel lode.' Further, in many lodes, especially those which occupy a line of disturbance in the strata, a coating of hardened clay lines either wall, and thus separates the main

' W. Pryde, Mineralogia Comuimsts, 1779,

l6 METALLIFEROUS MINERALS AND MINING.

lode stuff from the adjoining strata. These coatings are called the 'capels' of the lode.

Pryan Lodes, — Lodes that are filled With sand and heterogeneous materials, loosely cemented together in a mixture of clay, are called 'pryani lodes,' from pry the Cornish word for clay.

Quartz Lodes, — Fissures filled with hard spar or quartz, are quartz lodes. Quartz occurs in lodes in different conditions. Associated with iron it is grey, brown, yellow, and black in colour, and so approaches a gossany structure. It also occurs in different degrees of density. Now it is compact and solid, filling up the whole of the lode, then it is mixed with other materials; again, it has a loose sugary structure, from which it passes often into a beautifully crystallised form. When these crystals are not large, and stretch and meet across portions of the lode, as seen in figs. 48, 49 and 50, the lode is still further distinguished as comby.'

Sparry Lodes, — When a fissure is filled with fluor spar, baryta, or carbonate of lime, or all combined, it is called a sparry lode.' As intimated before, lodes of this description prevail mostly in limestones, the others belong chiefly to the older rocks.

Flookan or Flucan Lodes, — When a crack is filled up with stiff glutinous clay, it is known, in Cornwall especially, by this name. As sand and pebbles become mixed with the clay, the flucan passes into a pryani lode. These flucan lodes are usually cross fractures of dislocation, whereby the larger lodes are disturbed, as already described with reference to figs. 5, 6 and 7.

Grouan Lodes, — In passing through granite rocks, fissures, as I have already said, become filled with various-sized fiagments of partially decomposed granite. Grouan is a name locally given to granite, hence its application to lodes of this variety.

In this description of the different kinds of lodes, I have enumerated the principal earthy ingredients with which they are filled ; and it is in them, as in earthy matrices, that we find distributed, ofttimes with apparent irregularity, but, perhaps, with more regard to order than we usually deem, the ores of the metallic minerals we have further to consider.

Chapter Iii.

Metallic Contents Of Lodes,

Affected by Nature of Strata — Modes of Occurrence — Origin and Derivation— Infiltration — Condensation — Sublimation — Causes affecting the Particular and Local Deposition of.

The nature of the strata traversed by lodes is found, from long observation, to determine to some extent the kind of metallic ore that predominates in the latter. Of this we shall have many examples in the course of our inquiry ; and it will suffice to say here, generally, by way of illustration, that quartz lodes passing through granitic rocks, especially when pyrites are present, are the favourite resorts of gold In North Wales the hard blue slates of the Llandeilo strata are favourable for the production of lead. Lead is also the prevailing metallic ore in limestone rocks, although there are occasionally deposits of copper. Alternations of greenstone and porphyritic rocks with slates produce copper. Granite, especially the upper, coarse, and partially decomposed granite of Cornwall, is the prolific rock for tin. A lode, therefore, changes in the character of its contained metallic ore ; as in Cornwall, a lode passing through bluish killas,' or slaty rocks, contains copper, which gives place to tin when the underlying granite is reached. In Shropshire, also, the lodes that are productive of lead ore in the bluish grey slaty rocks of the Llandeilo sehes, become poor in lead and richer in copper as they pass into the underlying grits of the Cambrian rocks of the Stiper stones and Longmynd.

Metallic ores occur in lodes in a variety of ways, as (i) sprinkled in the midst of solid quartz ; (2) filling up as a solid body the whole of the crack ; (3) forming nests and pockets

1 8 Metalliferous Minerals And Mining.

connected by strings ; {4) forming a considerable deposit on one side of the lode, and when discontinued on one side commencing on the other; (5) irregularly dotted over the whole width of the lode ; (6) in rular layers, which, from the centre of the lode to the sides, answer each to each, and, when space permits, between them, crystallisiog into their beautiful characteristic fonns, as shown in figs. 4, 8, 9, 10, 11, 12, 48, 49, 50 ; and other figures occurring in the course of this book, which represent actual lodes, will illustrate most of these modes of occurrence. Besides the foregoing, there is an almost infinite diversity of combinations, many of which will come under our notice as we proceed.

At this point, and before I describe the remaining classes of metallic mineral deposits, it will be convenient to ask, and to endeavour to answer the questions, ''Vi'i'™* wKK " Mc "iNc''*Ro"o> Whence were these me- Husn or Rock akd'oiw ckhinibdto- tallic minerals originally QuAitTi derived ? and by what

means did they get into lodes as we now find them ?

A great deal has been written on this difficult natural problem from the days of Job until now. Especially has the inquiry been attractive since Werner taught with such power in the Mining School of Freiberg, a hundred years aga Each author has his favourite which he usually expounds to the excluon of all others. The true answer, as I take it, The mode of the origin and means of the deposition of

THE OKIGIN OF METALLIC MINERALS. ig

metallic minerals are not one only, but many. We should therefore endeavour to assign to each cause, or set of causes, its proper place and degree of influence in the whole range ot the causes thai have contributed to the final result'

To begin at the beginning, we may safely suppose that the metals, together with all the simple elements we have enumerated, formed part of the original mass of this globe when in a molten state, as is now reasonably inferred, it was first started on its revolving course through space.

It follows therefore that, as the outer surface of this molten mass cooled and hardened, the metals contained at various points would be enclosed within the outer crust in both ! collected and disseminated forms. The disseminated metals would be those distributed and quickly fixed through the whole mass. The collected metab would be those which in a fluid or

semifluid state gravitated '''F*r.lr:w";:o'a,lv"rLr"cA,!A* towards cracks, cavities, "m'l.o" ob" AKo*iD*oi1s ntHwa and shrinkages of the con- '"tbrstici*. taining rock. Especially would this retention of the metallic constituents near the surface be most complete where the cooling was most rapid ; where, on the Other hand, the cool-

' See Werner's /fan Thtory of Mineral Vdm ; Robert Were Fo, On Mnerai Vtins; De la Becbc's Geolegy of Contwail; Von Cotto, On MiMtnU PHnt, Stimon. On Afaural Vtiiis; Henwood's Araam/tnuu £>ttenli, &c

20 Metalliferous Minerals And Mining.

ing was slow, the metals, by their greater weight, density, and fluid nature, would sink down with the inner molten matter, leaving such parts of the surface barren of metals.

When, in course of time, an atmosphere encircled the earth, wd moisture descended in rain and accumulated in hollows on the surface, a wearing-down process began, fay which portions of the original cnist began to be abraded and washed into watery hollows, there to be deposited in a new form as sedimentary strata. The contained metals would be washed away along with their enclosii rock, and would be disseminated throughout the newly forming strata. They would form deposits in hollows of the seabottom, interstratified layers, fill up cracks, and altogether the strauinthe neighbourhood of an original me- Pic. ID.— Sectiom of THt DuBt Fbiheih lodk, talliferous mass would ""' "iBiiiG. highly charged with

nation and form. As these sedimentary strata became cracked and fissured by subsequent elevation, drying, and disturbance, the water flowing through them would take up the metallic particles, and, meeting with partial stoppages and interceptions as it passed through cracks and cavities, would deposit its heavy mineral burden on the floors and sides of the same. The power of the

INFILTRATION. CONDENSATIOf . 2 1

water to dissolve the metals out of the enclosing strata would be assisted by its associated chemical agents — acids, salts, and the like — as well as by the high temperature which it is likely prevailed in the earliest periods of the earth's history. The power of the agents being spent, the temperature cooled by any cause, and the flow of the water interrupted, the mineral matter held in solution would be deposited as we have supposed. Thus, by means of infiltration, we have one, and perhaps the principal, explanation of the deposition of metallic minerals in lodes.

Further, we may suppose that portions of the water would find their way down cracks to the molten masses lying within the fiery chambers underneath the cooling crust ; and how, reascendmg in vapours mineralised

hv rnntart with Fic. m.-Sictiob of Lonrn at Altb HapniuHC Gotts oy coniacr Wlin Mim, mbah Fmimitc, BHowwcfiiAoiiMKTsorRocK

other molten matter, makcabbi, ahd ikih ora. they would permeate cracks and chambers, penetrating every opening where they could unhindered find theirway ; and how, condensed by contact with the cooler surfeces of hardened rocks, the contained minerals would be deposited on the surfaces of these as far as the vapours reached ; just as mineral matter is deposited and accumulates on the sides of boilers and within steam pipes. Thus in a second way, by means of condensation.

22 Metalliferous Minerals And Mining.

we can conceive how mineral matter may have been deposited] in lodes.

Again, we may imagine how, in the intense fiinon and combination of molten substances going on amidst the heat of the earth's great laboratory, gasea would be driven off and forced upward throngh every fissure and chink along the course of which the contained metallic matter would be deposited ; just as the lead, sulphur, arsenic, and other minerals that escape in fumes from reduction furnaces, are now intercepted and deposited [ in the long flues and great

(chimneys of our chief mines and smeltinghouses; 1 and thus, in a third nay, by sublimation, we see how the eanh's cracks may have become lined and charged with metalliferous ores. ' I The precise places and I methods of the deposition I of metallic ores, thus brought generally from above and below, would depend upon a variety of causes. It would be determined in the first place Fio, I).— SicTioH OP LoDi AT TiH Altis by the direcUon of the SHOWING QuAiTiAHDMicAcicusSuTEtH ciacKs Tcady to DC tilled.

productive lodes run roughly from east to west They are evidently the oldest cracks, inasmuch as the north and south cracks cut them through and disturb them. The great work of charging the lodes with metallic matter seems to have been partly completed before the north and south fissures were made. This east and west direction trf" the older cracks may have re-

Influence Of Electricity. 23

suited from the tendency there is, when a strain is applied to substances, to break across rather than along their length. Then this east and west direction seems, in connection with electricity, to have had an influence on the deposition of metallic matter in these lodes. The water filling the fissures, heated from below, and charged with mineral matter, would be ordinarily a better conductor of electricity than would the adjacent rocks. Currents of electricity would, iif not otherwise controlled, pass along it to the west. These currents would assist in decomposing the mineral salts, earthy or metallic, and lead to the negative pole or rock. The deposit would further be influenced by the composition of the rock traversed, which, according to its enclosed minerals or temperature, would be electro-negative in one place, and electro-positive in another. The regularity of the deposition would also be interfered with by a variety of circumstances — the evolution of sulphuretted hydrogen by some, the absorption of oxygen by others, and the solidifying of the minerals. Thus the flow of the currents would be interfered with.

We can also readily see that the quiescence or otherwise of the water would afiect the deposit Where the water was in* tercepted and lay quiet, as in cracks in hard rock closed up above and below by shale and mud, the deposition of mineral matter would be most perfect; just as it is in quiet pools and precipitation tanks, rather than in raising streams, that solid matter is deposited from water now.

Referring again to the three methods by which we have seen how fissures may have been filled with metallic minerals, I may further observe that, generally speaking, it is among the lodes that traverse the oldest granitic, gneissic, and metamorphic rocks of the Laurentian and Cambrian groups that we find indications of the two latter modes of origin ; while it is in the clay slates of the Cambro-Silurian and Devonian, and in the Carboniferous Limestone, that we find abundant examples of the first method.

Thus, in Yorkshire and Derbyshire, it is when passing through the synclinal troughs or hollows formed by the limestone beds that the lodes are most productive of metallic ore.

Robert Were Fox, On Mineral Veins,

24 Metalliferous Minerals And Mining.

Such lodes as are filled with breccia and drifted materials, in which are lumps and aggregated masses of ore, are doubtless due to infiltration. Solid metallic lodes — where the ore is very pure and, filling the whole chasm, is hardly separable from the walls of the lode — seem to point to a sublimated origin. Where, again, the metallic matter occurs in parallel layers, the result may have been occasioned by gradual condensation from ascending vapours. Where, however, such layers are loose in texture, and the enclosing mineral coarse, the result may have arisen fi-om infiltration.

Probably in the same lode, each of the modes of operation may have been employed, in its turn contributing its quota to the final result

Chapter Iv.

Second, Third, And Fourth Classes Of Mineral

Deposits,

Stratified Mineral Deposits — Irregularly Stratified Deposits — Contact Deposits— Segregated and Crystalline Masses of Ore — Flats — Irrjular Deposits — Pockets — Contact Deposits — Network df. Veins — Disseminated Ores — Superficial Deposits.

I NOW proceed to notice the second great group or class of mineral deposits, and begin with those that are regularly stratified.

11. Beds.

(a) StraHfied Mineral Deposits. — Metallic ore deposits, especially those of iron and copper, firequently occur as beds ordinarily interstratified with other beds. Of these, we have examples in the ironstone layers of the coal measures; the ironstone beds of Missouri (fig. 1 14), the copper deposits of Anglesea (figs. 53,54 and 55), the copper deposits of the New Red Sandstone, and the ironstone seams of the Jurassic strata, fig. 113. Of course all stratified beds contain a larger or a smaller amount of metallic matter, especially iron, those we are now considering differing from the ordinary beds in the greater amount of metallic matter with which they are impregnated, and which renders it profitable to work them.

A stratified bed may have become charged with metallic matter in several ways. For example, (i) the water in which it was laid down may have been supplied with the mineral it held in solution, to be precipitated on its bed, from vents and communications with the earth's interior, as for example, by mineral

26 Metalliferous Minerals And Mining.

springs, or submarine volcanoes. It would thus derive its supply, first hand, from the original source. Or (2) the mineral may have been brought into the water by streams flowing into it from rocks already impregnated with it ; just as on the coast of Peru and Chili the sea contains so large a proportion of silver brought down from the mountains as to plate the copper sheathing of vessels remaining in its waters.

Such a process would be more intense m some regions than in others ; and at such points the deposits forming on the sea floor would be most strongly charged, the mineral matter lessening its quantity as it receded from the centre of action.

{b) Irregularly Stratified Mineral Deposits. — The regular or irregular stratification of such a deposit would depend upon the pre-existing contour of the sea bottom, the action of tides and currents ; and it would also be affected by the different specific gravity of the substances thrown down upon it

When land was depressed below the sea level, its surface would present all the inequalities which had, been made upon it by abrasion and disturbance. It would have escarpments and valleys, hollows and protuberances ; and the effect of the first matter deposited upon it would be to fill up the hollows. Moreover, the heavy metallic constituents would sink to the lowest points, and. would thus form irregularly stratified deposits.

{c) Contact Deposits. — Such deposits would make one form of contact deposits, or deposits lying between two dissimilar formations ' which would follow the undulations of the surface of the older strata.

{d) Segregated and Crystallised Masses of Ore. — Again, in shallow seas, a process of jigging and huddling would be going on on a large scale, in which, by means of tides, storms, winds, and currents, the lighter earthy matter would be carried away, leaving the heavier metallic particles in coalescing masses behind. To this mechanical action we must add the chemical processes, dependent upon the liking or affinity which one metal has for another, resulting in the readiness with which some

Flats In Limestone.

coalesce, and the force with which others repeL Thus on a

lac scale the processes of precipitation, segregation, and rough ctystallisation would go on nhidi we see exemplified in smaller chemical experiments within out own laboratories. These lenticular, wedge, and irregularly shaped mineral masses would in their turn be covered over by earthy matter ; and if we think of the subsequent process by which the strata in which they are enclosed have been upheaved, hardened, and tilted at all angles, we have imagined the probable history of deposits like the iron ore deposits of Norway (fig. 108), the zinc otb deposits of Belgium (Hg. 104), and of others described in this Book.

{e) Flats.- — Flats are of three principal kinds, r. There are the flats that occur in the limestones of the North of England, described in Chapter XXV.. There are long stretches of alternating shales and lime- 1 stones, the latter of a sandy g and readily decomposing kind, that contain irregu- , larly shaped deposits of ore extending horizontally to a great distance, but limited „ ,

? , , ' ... P"=- 13.— IlitHTKATlON OF ClAClt POLLOWIHG

in depth to certam beds, o' wiahmt kuistahcl

They arc portions of the ' lJJweie. ., Shalo. 3, FlMarged nrhli

limestone mineralised (see

figs. 93 and 94). Flats are also of another kind. Recurring to the phenomenon of shrinkage, which, as we have seen, is irregular according to the texture of the strata, we find that, in strata composed of limestones alternating with shales, the cracks in the former are intercepted by the latler, and are not always continued in the lower limestones immediately under those of the upper. We find the crack passing down the shale along the dip of the beds, and starting downwards through the underlymg limestone, where the power of resistance has been weakest, as seen in fig. 13.

A good illustration of the way in which a crack becomes more horizontal and usually less productive as it passes through

28 Metalliferous Minerals And Mining.

intervening strata beds, is seen in fig. 1 4, adapted from Wallace, which is a section of a lode on Alston Moor, in the North of England.

Usuallya good part of the shale bed has been washed away, and its place has been taken by clay, in which axe imbedded

Fic. 14.— Section of Lopb at Alston Moon. iNOvnNC Chancis op Dir and Tliick pcrpcDdicuUr putt moM productiK.

almost pure lumps of galena, which have been washed from the lodes above and the overlying limestones. A third kind of flat has been occasioned by a sinking or subsidence of the lower portion of a series of limestone beds leaving an irregular crack partly horizontal which has subsequently filled with earthy earthy minerals and metallic ores. Fig. 97, Chapter XXVI., is a representation of such a flat as it occurs at the North Hendre Lead Mine, in Flintshire.

Pockets. 29

III. Irregular Deposits.

I will begin the description of this class of deposits with —

(a) Pockets, — Pockets, bonanzas, vughs, or cavities, filled with ore, are of frequent occurrence, especially in limestone strata. Of this kind of deposits we may take the haematite deposits of the Forest of Dean (fig. no, Chapter XXIX.), and the silver lead ore deposits of the Eureka and Richmond Mines, in Nevada (fig. 41, Chapter XII.).

Pockets like those of the Forest of Dean may have been formed at the time of the deposition of the strata, in the manner just described ; for we have only to suppose that in a given stratum segregations of metallic ore took place, and the insterstices filled up with ordinary calcareous mud, to see how pockets that occur along the line of bedding in unbroken strata may have been formed.

But pockets have at times no reference to the stratification; they are not found in one or more beds along the direction of their bedding, but crossing the stratification somewhat irregularly, as is the case with the Nevada pockets (fig. 41, Chapter XII.). This kind of pocket is usually found in limestone strata. Now in all such strata may be seen, wherever they are quarried, great irregular patches of what is known among quarrymen as rotten rock.' This is rock from which lime is largely absent. It consists often of loose, friable sandstone. Where such a deposit lies, as is often the case, under a crack communicating with the surface, with one leading -out below, the result is the washing away of the whole friable mass, and ordinarily the formation of a cavern in its place. This cavern, like a fissure or lode, is now ready to have deposited within it the minerals held in solution by the water passing through it The deposition of mineral matter will go on fastest when the flow of the water is most checked. Where the flow is swift and continuous, a cavern alone remains, like those common in the Carboniferous limestones of Wales and York-

30 Metalliferous Minerals And Mining.

shire ; but in the former case a pocket or bonanza, charged with metallic and other minerals, is the result

(3) Contact Deposits. — (c) Network of Veins, — (d) Disseminated Ores, — Among the older strata we have many examples in eruptive rocks how, at times, from pressure applied elsewhere, portions of molten matter have been forced up from the interior of the earth, and have overflown the surfaces of the strata they have burst through.

Now the intense heat attendant on such eruptions would have, and indeed has had, great effect upon the adjacent strata. It has hardened them, changed their character — in the language of science, metamorphosed them.

We may easily imagine how any metallic substances they contained would be melted, would fall down as far as they could, filling up every crevice they could find, and would often at last nestle in hollows at the point of contact with the underlying eruptive mass, in some cases penetrating that mass itself In this, therefore, we find another explanation of the origin of contact deposits.

The eruptive mass would also be itself charged with whatever metals prevailed in it as it lay quiescent in the furnace below. In the process of cooling, especially if this were slow, this heavy metallic matter would sink to the bottom of the overflowing mass and gravitate towards hollows in the underlying rock. This aflbrds us an illustration of the way in which a contact deposit lying underneath an eruptive rock may have been produced

The metallic matter would also fill up cracks and gaps of shrinkage in the underlying strata, and thus form in another way network of veins like that of Geyer (figs. 67 and 68, Chapter XX.), already referred to, as well as gash veins that die out in depth, as in figs. 63 and 79.

Again, if the process of cooling were quick, as under some conditions, especially near the surface, it would be the metallic matter that would be retained in the eruptive mass. This retention might either be in fine particles diffused, as grains of gold and of tin occur in granitic rocks, or if the cooling were not veiy

Superficial Deposits. 3 1

rapid, in minute cracks threading the whole mass as the result of shrinkage, producing once more the phenomena of the stockwerk of Geyer just referred to.

A study of the volcanic phenomena observable at the present day, together with that of geysers and mineral springs generally, will serve to illustrate much of what I have been supposing, and help to elucidate this difficult subject in its varied and extensive bearings.

IV. Superficial Deposits.

In the drift and other loose matter that covers the more solid framework of the globe, we find important metallic deposits, especially those of gold and tin. We shall have occasion to notice these more in detail, so that it wiD not be necessary here to do more than say that they lie along the base of the mountains whose strata contain the deposits from which they have been derived The mode of their occurrence in beds, continuous or otherwise, will afford us additional explanation of the way in which the older stratified beds of metallic ore, regular or irregular, were originally formed.

I do not know that I have exhausted my list of all the possible ways in which the various deposits of metallic minerals may have been produced; but the illustrations and examples I have given will afford the student the clue to the explanation of the whole phenomena, and will help him to work out in further detail the theories as they aflfect the class and species of deposit m which he is most interested.

We may, therefore, now pass on to consider in detail each metalLc mineral separately, together with the conditions under which it it is found in various parts of the world.

Chapter V.

Gold.

Characteristics and Modes of Occurrence— Driftal Gold— Nuggets— Gold in Lodes and Veins — Alluvial Deposits of the Ural Mountains — Mining in the Solid Rock — Austro-Hungaxy — Mines of the Banat — Gold in Central Europe-Sands of the Rhine — Lodes and Alluvium of France, Spain and Portugal, and Italy.

Gold does not often occur in nature in a mineralised form, but is usually found in its native or metallic state. It is, however, frequently alloyed with copper, silver, and other metals. Rarely, as in Transylvania, it is found mineralised by association with tellurium.

In form it occurs as cubes, mostly small, which are often distorted and elongated. Also in grains and plates, in hairlike fibres, and in dendritic or tree-like incrustations.

Its hardness ranges from 2-5 to 3*0. The colour is yellow of various shades ; the lighter colours of which are due to the presence of silver in large quantities. Its specific gravity is very great, ranging from 12 '666 to 19*079, varying according to the metals alloyed with it, the purest gold being the heaviest.

From its resemblance in colour to iron the latter substance is often mistaken for gold. One easy test of the difference between the two lies in the great ductility and malleability of gold as compared with iron pyrites. It will flatten under a blow, whereas pyrites will crush to powder.

Indeed, one of the most noticeable qualities of gold is its extreme malleability ; a grain of it may be made to cover a space of 54f square inches, and it may be beaten into leaves

When perfectly pure, gold is called in commerce gold of 24

Modes Of The Occurrence Of Gold.

caratSj or fine gold. If it is alloyed with two parts of silver, or one part of silver and one of copper, or the like equivalent of other metals, it is said to be 22 carats fine. So, ii" it contains only 20 parts of pure gold it is 20 carats fine.

The two following analyses of gold will illustrate two extremely diflferent conditions of alloy and of specific gravity :

I. Gold from Russia.

Specific gravity, 19*099. Gold . . .9896 Silver . . . 0'i6 Copper . o*35

Iron . . 0-05

2. Gold from Marato.

Specific gravity, 12*666. Gold . . . 73-45 Silver . . . 26-48

General Modes of the Occurrence of Gold,-GoW is found in two widely different conditions. First, it is found distributed m gravel, sand, clay, and other detrital matters that cover the valleys and plains which furrow the sides and extend along the base of great mountain chains. This condition, although the newest presented in natiu-e, is probably the oldest in which gold seems to have been known to mankind. Probably all the gold of ancient times was derived from such sources; the earliest explorers having been attracted by its rich, shining, yellow appearance, as it glistened in the river sands.

The drift containing gold has, of course, been produced by the whole array of abrading causes— the atmosphere, rain, rivers, sea, and ice — all of which have helped in their turn, and with various combinations of effort, to disintegrate and displace the solid rocks, and to sjwread their ruins over the valleys and plains.

Probably the peculiar disposition of the gold in the drifts of any one locality has been affected by the prevalence or greater activity of one or more of these agents over the rest.

Gold occurs in these drifts in fragments and grains of all sizes. The larger lumps are known as nuggets, and some of these have been found of a large size. The largest known was found in California, and weighed 134 lbs. 7 ozs. Another weighing 96 lbs. was found near Miask, in the Ural Mountains,

D

34 Metalliferous Minerals And Mining.

and is now in the Museum of the Imperial School of Mines at St. Petersburg. Another of 27 lbs. weight was also found in California.

Dr. Genth suggests that the gold of the larger nuggets was originally disseminated as fine grains throughout the parent rock, from which it was dissolved and washed out, to be again segregated or collected into lumps and masses of irregular and often fantastic shape in the waters of the driftal seas. I may observe as a digression that he applies partly the same theory to gold found in veins ; inasmuch as he has found the native bismuth from the peaks of Sorato, in Bolivia, interlaminated with gold, and the ore bed in the metamorphic slates at Springfield, America, to consist in its upper part of magnetite, in its lower of copper pyrites and other ores, and interlaminated with these fihus of native gold. To return, as washings, diggings, placer, and hydraulic mines, these drifted deposits have been worked for gold from the earliest times until now.

Secondly, gold is found in lodes and veins, chiefly filled with quartz, that traverse the older slaty and metamorphic rocks, principally those of Cambrian and Laurentian age, as well as finely disseminated in rocks of a granular structure. This form, although the oldest mode of occurrence in nature, is the one more recently known to men, and still more recently worked with success. Excepting some of the Brazilian mines, and one of doubtful success in the Ural Mountains, there was, only forty years ago, scarcely a gold mine profitably worked in the solid rock.

The explorers for gold in drifted matter have gradually followed the object of their search up the mountain sides, until they have struck in veins and lodes some of the sources whence the alluvial gold has been derived.

The diagram (fig. 15) which represents the structure of the Ural Mountains, to be noticed presently, will illustrate the relation borne by these two classes of deposits to each other. The size of the quartz veins is necessarily exaggerated.

American Journal of Scieme and Art, September 1859.

Cold Of The Ural Mountains. 35

With these general prefatory remarks I will proceed to notice the chief gold producing districts of the world, beginning in the east with the

Ural Mountains.— The Ural or Oural Mountains extend from the Arctic Ocean to the Caspian Sea,' a distance of 1,000 miles from north to south. Along their course they form the natural boundary between Europe and Asia. A few of the highest peaks reach an altitude of 5,000 feet, but the greater number do not exceed 3,00a feet

Referring to the section, fig. 15, the groups of strata, i, 3,

3. Mioinoui, ulcoK, and ArgUlAtxoul ilmy rockl, vint conlaimng l.iuRntUui And CHmbriUL I eoM.

nieuin 6. PennunK?d newer 7 7'7'!°Dnfi'filUiii hollow/ ncki. wiih [did. ctpecuUy u ihe base of th* driil.

and the lower part of 3, are penetrated with greenstones and porphyritic rocks, often in a crystallised and mineralised form. The gold is frequently found disseminated in these intrusive and imbedded rocks, as well as in the quartz veins that traverse them, and the groups i and t enclosing them. The Stratification is the same on both sides of the chain, and on the eastern, or Siberian side, gold is visible to the naked eye in the slaty rocks 3. It is probable that gold will be found in greater or less quantities all along the range, but at present the gold-producijig region is almost limited to the country lying between the 51st and s6th degrees of N. latitude, with the Europe and tMt Ural Btmnlains. (Murchiion

36 Metalliferous Minerals And Mining.

town of Ekaterinburg in the centre. The entire gold-producing country of Russia is, however, estimated by M. Boglubski ' at 2,000,000 square miles. Unless others have been started recently, the only underground mines are those at Berezoosk, near Ekaterinburg, on the Siberian side of the mountains. It was here that mining operations were first commenced on the first discovery of the gold in 1723. The rock here is decomposed granite, containing numerous veins of quartz, in which the gold is scattered. Shallow shafts are sunk in the rock, and levels 'driven into the veins, and the production of these underground mines, from the year 1725 to that of 1841, was estimated at 30,000 lbs. troy of gold. In 1850 the yield was 100 lbs. The analysis of the gold of these mines stands

thus —

Gold 09280

Silver 00702

Copper 00*006

Iron oo'OoS

hoss 00*004

Attempts at mining in the solid rock were made up to the year 1823 in sixty-six other localities, but these were all abandoned ; for thus far the Russians have found it easier to obtain gold by digging and washing the drift lying in the higher valleys and hollows of the mountains, and the low-lying land stretching eastward into Siberia. The drift seems to be of the same age as our glacial drift, bones of recent and recently extinct animals being found in its uppermost layers. Gold is most plentiful in it where the drift is most largely charged with iron. Fig. 16, adapted from Murchison and Vemeuil, is a section of the drift at the Sormanosk mines, near Miask, the shaded portions, just overlying the upturned and eroded edges of the underlying strata, showing the auriferous portion of it

The gold washings of the Ural are of recent date. The few there are on the western side were established by the

' Gold and Gold Mining in Russia.

Cold Of Hungary. 37

Gnvernment in 1819, and those of the eastern in 1838. The proportion of gold obtained is from 65 to lao grains to 4,000 lbs. of the enclosing drift, the annual production per man being ilbs, in the private works, and ribs. in the Government

Whitney,' writing in 1854, described the production of these

I, Crauiuc ud inelBic rodu. CrrmJIiin limotoae. 3, AurilenHU drift, ji. Drift

Russian gold fields as having reached its maximum in 1847, and as steadily declining, and likely to decline. The result has been better than he anticipated. The entire gold production of Russia last year being 66,956 lbs. against 42,000 lbs. in 1841.

The exceptionally good year was 1847, with a production of 75,000 lbs.

AusTRO-HuNGARY. — Gold has been mined in Hungary since

Maiiu Wtaith of Iht U'oUd Statu.

38 Metalliferous Minerals And Mining.

the eighth century, and extensive remains of ancient workings still remain. Mines cluster around the towns of Schemnitz, Kremnitz, and Neusohl in Lower Hungary ; the Amalia mine near Schemnitz being now worked for gold at a depth of 600 yards. The mode in which gold occurs with other minerals will be illustrated by fig. 17, which is a section through the Oravicsa group of mines in Lower Hungary, closely adjoining Transylvania. The deposit at the Elisabetiia Golgotha mines fills up a cavity in quartzose and calcareous rocks. The earthy part of the deposit consists of Augments of limestone, some of which are of large size and are rounded by aqueous action. These, with quartz fragments cemented together in a clayey matrix, fill the middle part of the cavity 4. In this gangue, gold is found in separate grains, and also associated with pyrites. A layer of tough clay two to three feet wide is sprinkled with thick threads and grains of gold which are associated with auriferous pyrites. Small veins of quartz and calcite containing gold in these different conditions also penetrate to some depth the imderlying calcareous rock. It is from the disintegration of such as these, probably, that the metallic deposits are derived. The quartz veins are often worth 100/. per fathom. The pyrites in the main deposits are not very plentiful, but they contain from 6 to 10 oz. of gold per ton, and rich lumps of gold are attached to the boulders of the deposit. In the clayey band gold is associated with rare and interesting minerals, as glaucodote, alloclase, bismuth glance, specular iron, and cobalt blume. In the central breccia these minerals give place to mundic, lead, and antimony. The proportion of silver to the gold is one-eleventh. The associated auriferous mundic is sold at from 7/. to 10/. per ton, and the bismuth at 22s, per lb. The gold is sometimes closely associated with tellurium, and mineralised by it

Central Europe. — Although no productive gold mines, either hydraulic or underground, are worked in connection with the older rocks that form the central axes of the mountainous

See also Minify Journal 1878, p. 140, et seq.

Gold Of France, Spain, And Italy. 39

network of Grermany and Bohemia, yet these strata must contain an appreciable quantity of the metal, inasmuch as the sands and mud of the rivers Danube, Rhine, and Rhone contain small proportions of gold.

Those of the Rhine are, or were recently, worked between Bale and Mannheim, gold to the value of 2,500/. being extracted yearly. The sands worked near Strasburg are estimated to contain 30 parts of gold m 100,000,000. Occasionally the proportion reaches double this amount. If it were not for the cheapness of laboiu*, gold in such minute quantities could not be profitably extracted. The wages of the Rhine goldwasher are usually not more than lod, a day, sometimes they reach i. 8//., but never exceed 2s, He usually treats 11 J tons of sand per day.

Franck — In France some of the lead lodes contain minute quantities of gold. An auriferous quartz vein, the only one known, occurs in the older rocks at Lagardette, in Isfere, department of the Basses-Alpes ; and the alluvium of the neighbouring rivers are reported to contain gold; but none has been obtained in recent years.

Spain and Portugal. — These countries are said to have yielded considerable quantities of gold in ancient times. In the time of Pliny, Galicia and the Asturias were considered the richest gold fields known, yielding 20,000 lbs. annually. Recently operations have been confined to washings on the rivers Sil and Salor, the produce of which is estimated at about 2,000/. per year. With the influx of English enterprise and capital, this branch of mining industry in Spain may, under safe government, revive.

Italy. — Gold was mined in Italy in ancient times. It is still obtained at the Pestarena mines near Valanzas. The lodes which traverse the older rocks consist of white quartz that contain iron pyrites, lead, and blende. When carefully selected the lode stuff contains from 9 to i3. of gold.

Chapter Vi.

GOLD — continued.

Gold deposits of Gogofau — The Dolgelly District — Scotland — Ireland — In situ and in Alluvial Deposits in County Wicklow.

Britain. — In very minute quantities gold is present in the seasand and river detritus that occur on the western shores of the island, where the older rocks form the rugged surface. It follows, therefore, that these older rocks must contain some proportion of gold in situ. There are the remains of a mine at Gogofau, west of Llandovery, in South Wales, where the Romans worked a gold mine in large quartz veins, that traverse slaty strata of Arenig or Upper Cambrian age. There are yet visible the stones and troughs they used for crushing the vein stuff, and traces of the aqueduct by which the water was conveyed for washing. The veinstone still shows on analysis minute quantities of gold diffused throughout it*

The most important gold region of Britain lies on the north side of the estuary of the river Mawddach, in Merionethshire,* and it occupies both sides of that river as it bends from Dolgelly towards the hills about Trawsfynydd. There are traces of old Roman and it may be British mines ; but in recent times the region was found to be auriferous, about the year 1844, by Mr. Arthur Dean, who, on examining the ore and debris heaps of the Cwmeisen lead mines, found fragments of ore that contained as much as 7 oz. of fine gold to the ton.

Sir R. I. Murchison, Siluria.

Ramsay, Geology of North Wales ; Dean, British Association Reports 1S44 ; Calvert, Gold Rocks of Great Britain and Ireland ; J. A. Phillips, Gold Mining and Assaying,

Gold Of Merionethshire. 4I

This discovery lead Mr. Dean to examine the whole of the Dufiws range of mountains, when he found that many of the quartz veins and lead and copper lodes of the district were impregnated with gold. Trials were made by local explorers, among whom were Messrs. Parry and Williams, who, after many failures and much trouble, succeeded in making the discovery of gold at the Vigra and Clogau copper mine, from whence they obtained gold to the value of 36,000/. The importance of this discovery (in 1854) was, however, greatly overestimated, A mania for gold mining set in. Companies were formed with quite the fliil complement of chairmen, directors, secretaries, engineers, managers, and assayers ; costly machinery was procured and conveyed at great cost to this hilly region, then destitute of railways. The result was disappointment, and the traveller may see, as I often have seen, in the remains of massive and costly machinery stranded on the hillside, traces of the fatal collapse of the gold fever. Even the mines which had yielded enough of gold to remunerate the native economical workers collapsed utterly under the more elaborate and costly direction. It may be well to place on record the names of a few of the mines that were started. Among them were Berthllwyd, Cwmeisen, Cwmeisen Issa, Dolfrwynog, North Dolfrwynog, Gwynfynydd, Tyddyn Gwladys, and the Vigra and Clogau, where the great discovery was made. This mine is now the only one at work. In 1875 it produced 548 ozs. of was 447 ozs. lodwts. i5gms.

The strata in which the auriferous lodes occur belong to the junction of the Lower and Upper Cambrian stiata, where the Lingula flags of the latter rest upon the uppermost grits and quartzites of the former group. They consist of talcose and steatitic slates, which decompose at the surface to an unctuous clay. Iron and copper pyrites are disseminated throughout the rock, and there are numerous minute copper veins.

The lodes of the district may be grouped into three classes: I. Quartz veins containing ores of silver, copper, and more rarely lead and blende ; these have a direction NW. and SE.,

42 Metalliferous Minerals And Mining.

and dip to the north. 2. Veins filled with carbonate and sulphate of barytes, with lead and blende, but seldom copper ; these are NE. and SW. veins, dipping south. 3. Auriferous eins, which trend due E. and W., and dip to the north. In width they range from a mere thread to six inches, and rarely opening out to two or three yards. These veins pass through the other mineral lodes, and it is at the points of intersection that gold is found most plentifully in the quartz veins.

It there occurs in grains, which often enclose a minute grain of quartz ; in thin films upon spar, and where the quartz is cellular filling with other minerals the minute cavities. The second group of veins are the poorest in gold, even at the points of intersection. It is in the crossing of tiie groups i and 3 that the metal has most accumulated.

At the Vigra and Clogau mine, the gold is obtained, or was when I examined it in 1865, from irregularly branching veins of quartz, which, are sprinkled with iron and copper pyrites. The gold was then mostly visible to the naked eye, and distinguishable from the pyrites by its deeper yellow colour. At various points where the veins cluster together, the gold was most abundant, and these richer points were connected by veins and strings of quartz barren of goldi In 1875 1,216 lbs. of selected quartz from such points yielded 73-J- ozs. of gold.

At Cwmeisen mines an assay of oxides of iron showed 18 . 3 gms. of gold to the ton of ore. Another assay gave of lead 67 ozs., silver, 10 oz. 5 . 8 gms., and of gold i oz. 15 .

At Gwynfynydd mines the lodes were quartz, containing minute specks of gold sometimes visible to the naked eye. They held also gold-coloured mica, containing a little of the metal, and the gold was distributed alternately upon the hanging and the heading sides of the lode.

At Dolfrwynog the chief gold-bearing lode was quartz, with a branch of sulphate of baryta running through it. On each side of the barytes \vas a seam of lead, which in places gave as much as from 50 to 60 oz. of gold to the ton.

Gold Of Scotland. 43

At Berthllwyd blende ore was found, in which the contained gold ranged from i to 6oozs. per ton, with a fair proportion of silver.

The Welsn gold was all of a pale colour, owing to the presence of silver. Specimens obtained by Mr. Readwin from were 18 carats fine, one from the bed of the river Cain was 18 carats fine, and a crystal of gold picked up to the west of the south end of Bala Lake was only 14 carats fine. The present value of the gold derived from the Clogau mine is about 3/. iSs. per oz.

It remains to be seen whether, with strict economy and with the use of the most approved appliances for mining and dressing the ores, these North Wales gold mines can yet be made to pay. In a report of the Clogau mine, issued in 1875, it was stated that the yield of the rough ores was from 7 to 8 . per ton. If this quantity could be depended upon for any considerable length of the lodes the mine should profitably worked. From one of the rich clusters of veins before alluded to, 9,310 tons of ore gave 12,416 ozs. of gold, 22 carats fine, or nearly ioz. to the ton. The following analyses of two samples, by the late Mr. David Forbes, will show the character of the gold from this mine :

Gold . . . .

QO'l6

Silver . . . .

09*24

Copper and Iron

trace

trace

Quartz .

00*32

Loss . . . ,

00*26

00*19

100 'Oo

100 'Oo

Scotland. — Gold has been found in Scotland to some little extent, in strata similar to those just described. The men of the mining district of Leadhills, in Lanarkshire, have occasionally employed their leisure time in searching for the metal among the alluvial deposits and mine dris of the district Gold is also found in the drift of Sutherland, and it has been traced up the valleys to a great body of metamorphic rocks, which are pierced by intrusive granites.

44 Metalliferous Minerals And Mining.

Ireland. — Gold is found in situ in county Wicklow, where it is sprinkled throughout the sulphur course referred to in Chapter XVII. and shown in fig. 56. The proportion is greatest in the decomposed or gossany upper portion of the course. Two analyses gave respectively 7 . i2gms. and lydwts. i2gms. Subsequent analyses have given a smaller result. The returns from this source for the year 1878 only amounted to 5 oz. 3 . 1 7 gms.

Detrital gold was discovered in the same county in the year 1796, in the Balin valley brook, a tributary of the Ovaca river. In the autumn of that year hundreds of people were engaged in digging and searching for gold. In about six weeks from the time of the discovery the Government took possession of the place and guarded it with soldiers. Under the direction of some local gentlemen of mining repute, systematic operations were conducted, with little profit, until 1798, when the works were destroyed in the rebellion of that year. The works were resumed in 1801, and further explorations were made in the neighbourhood. Various attempts have since been made by private adventurers and mining companies, but these have from time to time been abandoned.

The gold seems to have been derived from the ferruginous quartz ridges that traverse the granitic and gneissoze rocks that form the bases of the mountain range, and also from deposits like the sulphur course described in Chapter XVII. The gold lay dispersed through a layer of gravel and clay, which was covered with fi-om 20 to 50 feet of superficial drift. With the gold was associated magnetic ironstone, copper and iron pyrites, and oxide of manganese. The gold occurred in grains and nuggets, from the most minute in size up to a nugget weighing 22 ozs. Analyses of the gold gave of gold 92*32, silver 6 '17, and of iron 078;

It is estimated that the peasantry during their six weeks' work obtained 800 ozs. the Government, firom 1796 to 1802, 944 ozs., and the Carysfoot Mining Company, firom 1857 to 1862, 85 ozs.

W. W. Smyth, Mines of Wicklow; Records of the School of Mines vol. i. ; Weaver, Trans, Gtol. Society, vol. v.

Chapter Vii.

GOLD — continued.

Eastern North America— New England Stales— Virginia— Nova Scotia- New Brunswick— Lake Superior — California and the Western States — Alluvial Deposits— Gold-bearing Strata — Statistics.

Eastern America. — The eastern slopes of the Appalachian mountains appear to be among the oldest gold-producing countries of the North American Continent. Gold washings seem to have been carried on in very early times by the Indians in the Nacooche Valley, Georgia, where an Indian mining village was found by some modem miners buried nine feet below the

Fig. x8.— Ideal Section across the Appalachian Chain.

z X I, Cambro-Siltman, consisting in Canada of Potsdam sandstone, Trenton limestone, Utica slaie, and Hudson River group, a a a, Silurian (in Canada, Gasp limestone, ftc.). 333, Devonian. 444, Lower Carboniferous rocks and sands. 5, Coal-fields.

surface of the ground. There were thirty-eight low timber houses, all in a row, with their foundations laid in golden gravel, and relics of rude mining appliances lay about. When first found the land was covered with a rich undergrowth of timber. The sources of the gold in this eastern region lie in the base ment strata of the Appalachian and Alleghany chain of mountains, which, starting in the dominion of Canada and ramifying through Nova Scotia, run down the New England States, Virginia, the Carolinas, to Alabama and the Gulf of Mexico.

Fig. 18 will convey an idea of the general structure of these mountains as they pass through Pennsylvania.

Metalliferous Minerals And Mining.

In fig. 19 we have the intimate structure of the older rocks about the gold mines in Virginia ; and the diagram may be taken as a sufficient illustration of the condition under which gold is found all along the range from Canada and Nova Scotia on the north to Georgia on the south.*

In Virginia gold is worked in syenitic and slaty rocks, into the composition of which the usual materials — chlorite, felspar, mica, silex, and talc— enter with varying proportions. Quartzose beds, that alternate with the slates and veins of quartz, traverse the whole series. These* quartz beds and veins are cellular in structure, are readily broken, and contain water. They are frequently tinged with the red and brown oxides of iron, and contain copper and iron pyrites. Throughout this mineralised, quartz the gold is scattered in small bunches and separate grains. It is also sparsely sprinkled throughout the slaty beds.

A I 2 I 2 I

Fig. 19.— Sbction op Strata at Woodvillb, Viruinia.

The veins are nearly perpendicular. Their direction is from NW. to SE., and they are often of large size. They are more regular and continuous in the syenitic rocks. The gold from the slaty portion of the lodes is more flaky than from the syenite. The quantity of gold contained in the productive quartz varies in value from 25J. to 20/. per ton.

Near Woodville the interbedded quartz takes the form

, shown in fig. 19 : a is the basement, granite, and gneiss ; 1 1 i

are thin beds of buff and yellow-coloured talcose slate ; 2 2

are auriferous beds consisting of quartz and slate, with much

brown ore, and some iron pyrites. The gold is most plentiful

See Whitney, Metallic Wealth of the Untied States; Kenwood, Metalliferous Deposits; Morton, Engineering and Mining Journal of New Yorif vol. XXV. p.

Gold In Eastern North America. 4/

ia the brown ore and in the joints and cavities of the bed. As in Brazil, the gold is most plentiful when the iron ore and quartz are combined, and most scarce where either is alone.

The usual proportion of gold from these beds is 6 . to the ton of ore, and there is some silver in addition. As a rule where the gold is most abundant in these beds it is poorest in quality. Traces of galena are sometimes found.

There are alluvial works on the lower lands, and in Louisa County successful operations have at various times been carried on, during which nuggets varying in weight from one to several ounces have been found.

Southward, both alluvial and underground mining for gold have been carried on in the counties of Cabarris, Lincoln, and Mecklenbeig, North Carolina ; and in Union, Lancaster, and Chesterfield districts, South Carolina ; also in Georgia.

Nova Scotia. — Passing along the mountain chain and its spurs north and north-eastward, a few words will be necessary respecting the increasingly important gold districts of Nova Scotia, New Brunswick, and Lake Superior. In Nova Scotia the Rev. David Honeyman found gold in the year 1861, at the junction of the Truro and Halifax railways. It occurred in chloritic schists of Upper Cambrian age that contained auriferous quartz veins. In 1863 the yield of gold had increased 14,001 ozs. The production of this region in 1877 was 8,200 ozs., much of which was, from the alluvial deposits, derived from the denudation of the auriferous strata.

In central New Brunswick gold is found in river derived as in other cases from the quartz veins that intersect the rocks of the district

Far away to the NW., on the northern shore of Lake Superior, about Thunder Bay, similar strata to those 01 Nova Scotia are interstratified with Trappean beds, similar to the gold-bearing rocks of North Wales. Veins bearing gold traverse these from E. to W., in which free gold is disseminated

See Chapter VIII.

NicholsoD, Quarterly Journal Geological Society,

48 Metalliferous Minerals And Mining.

in copper pyrites, with occasionally galena, silver glance, metallic silver, and iron pyrites.

California and the Western States of America. — From the western side of the Appalachian Mountains the older strata bearing gold dip under the secondary rocks that underlie the great plains of Central North America. They protrude in minor ridges here and there, and at last finally emerge amidst the grand scenery of the Rocky Mountains. This mountain chain, consisting of its great central ridge of the Sierra Nevada, with the parallel ridges of Utah on the east, and the coast range of California on the west, starts, as I have said, far away to the north, in British Columbia, and courses down the western side of the North American continent to Mexico and the south.

It was on the western side of the coast, or Califomian range of mountains, on the American Fork, near its junction with the Sacramento, that gold was found in the drift of the river valleys and plains in the year 1848. A saw mill had been erected by Colonel Sutter, a retired officer, and on the first rush of water through the newly-formed millrace, an accumulation of shining yellow particles became apparent, which were soon recognised by Mr. Marshall, the owner of the soil, as gold. Although the attempt was made to keep the matter a secret, by the beginning of July San Francisco was emptied of its inhabitants, and on the arrival of Colonel Mason, the then Governor of California, on the spot, he found four thousand gold diggers and washers at worjc, who were supposed to be earning 7,000/. or 8,000/. per day.

The ride of immigration flowed rapidly during the early part of 1849. By July 15,000 Mexicans and Chilians were supposed to be on the ground, and by the close of the year it was computed that 45,000 Americans and 5,000 foreigners were working at the diggings. And the yield of gold for the year 1850 was estimated at 10,000,000/.

The present magnitude of alluvial gold mining in California may be inferred from the statement that in 1873 there were 775 mining ditches situated in twenty-five counties. The

Gold In California.

ditches were of an aggregate length of 4,863 miles, along which water flowed daily to the extent of 300,000,000 cubic feet It is supposed that of the gold contained in the drift of that date, three-fifths were secured. In the early days of excitement and prosperity a very large proportion ran to waste, so that the Chinese settlers following here, as elsewhere, in the wake of the Europeans, made a living out of the leavings of the latter. The total yield of gold from California for 1877 was 15,000,000.

After the discovery of gold at Sutter*s Mill, the drift of Feather River, another tributary of the Sacramento, eighteen miles to the north, was found to be auriferous in its higher reaches. Stream after stream was searched and found to flow over golden sands.

The drift was, of course, also followed into the neighbouring territories. Lower California, Nevada, Colorado, Arizona, and New Mexico, and in each country finally traced to its source in the mountains.

From the accidental discovery of gold in the millrace at Sutter's Mill, only thirty years ago, has sprung gold mining operations the magnitude of which may be estimated by the returns lately given for the year 1877 of the production of gold in the Western States of America. These are as follows :

Arizona

350,000

California

15,000,000

Colorado

3,500,000

Montana

3*550,000

Nevada

18,000,000

,40,400,000,

or about ten million pounds sterling.

As might be expected from the same geological conditions, both as to the stratification of the mountains and the composition of the drift, continuing northwards into British Columbia, similar results have been attained there. The yield of gold from that country last year was 1,000,000, and at the present

Engineering and Mining youmalof New Yorky January 1878.

E

50 Metalliferous Minerals And Mining.

time the excitement of new discoveries and the flow of goldseekers thither is very great.

The gold-bearing drift stretches westward from the flanks of the Sierra Nevada, a distance of about sixty miles. It is, ot course, made up of the detritus of the gteat mountains on the east Its thickness varies considerably. On exposed surfaces and ledges of rock it consists of a few pebbles only, but it accumulates in the hollows and flats lying between the higher ridges of strata, as represented in fig. 20, to a depth of from six feet to several hundred feet Its usual composition in such places is on the surface a reddish loam mixed with small gravel Underneath this is a bed of rolled boulders, some of which weigh from two to three tons. These boulders rest upon a bed of gravel, that fills up the inequalities of the basement rock, and it is throughout this lower gravel that the gold is diflused. The whole series of the drift is often capped by a hard conglomerate set in clay, which has helped to preserve the deposits from denudation. There are also, both underlying the present river channels and sometimes hidden altogether under the drift, old river beds of great size and depth. These when struck and found to be auriferous are called leads.' The largest known of these, and one which may be taken as an example of the rest, is the Big Blue Lead. It has been traced from NW. in Sierra County, SE. to Forest Hill in Placer County, California, a distance of sixty-five miles. Its depth ranges firom one to three hundred feet Gold is distributed throughout the whole of this drift, which contains a preponderance of quartz boulders, some of which near the bottom of the old river bed weigh twenty tons. The particles of gold are found of larger size, and contain more silver, at the bottom than the top of this ancient drift, and are worth less by about 2j. 6d, per ounce. It is supposed that this difference in quality is caused by the larger size of the fragments below resisting more effectually the action of sulphuric acid, which, set free by the

Aiming Slatistics West of tht Rocky Mountains Raymond, 1870 ; Whitney, Metallic Wealth of the United States ; English Mining Journal, iSyj.

Proportion Of Gold To Drifts. 5 1

decomposition of pyrites, has eaten the silver out of the smaller grains at the top of the deposit

The quantity of gold in this lowest drift varies a good deal. At the top of the drift of the Big Blue Lead just described, the proportion varies in value from 2s, to 8. per cubic yard, but many places near the base have yielded 10/. to the cubic yard, or leaving out the big boulders, to two or three cubic feet Gold to the amount of 2s, per bushel of dirt is also a common estimated quantity in the higher hollows of the mountains, and the following are some recent particulars of less rich deposits in California :

In Nevada County, 275 cubic yards of drift gave gold equal to yd. per cubic yard.

Another claim in the same county, from 16,000,000 cubic yards of drift, gave 15//. to the cubic yard

In Placer County 43,000,000 cubic yards in the Gold Run district gave 2f //. per cubic yard, and in Yuber County 25,000,000 cubic yards from Smartsville gave 12/. per cubic yard.

The gold is ordinarily found in thin scales and minute grains, also in plates and lumps, and occasionally, especially high up the valleys, in lumps weighing many pounds. Each particular locality, however, presents its own variety of gold, in colour, size, and shapes of the grains.

Recentiy the shore sands of California, and the western coast generally, often black in colour, have been proved to be auriferous, and eflforts are now directed towards the profitable extraction of the gold from them.

This description of the auriferous driftal deposit of California will be generally applicable to the like deposits northward into British Columbia, and southward into Mexico.

The whole of these vast deposits of detrital gold are traceable, as in all the other instances given, to the quartz veins and lodes that intersect the strata of the lofty mountains, and to the grains of gold that are disseminated throughout the granitic rocks that lie at the base of the series. The region is so vast, and was so recently an unknown country to white men, that

E2

52 Metalliferous Minerals And Mining.

although the United States Government has its scientific exploring parties constantly at work, we have as yet but few detailed sections of the strata of these mountain ranges. The section, fig. 20, shows the general geological structure of the region, and it will help us when we come to speak of silver to define the metalliferous zones of strata.

The strata that look so orderly in the section have been upheaved, tossed, and sculptured into the grandest, wildest, and most fantastical forms. There are conical peaks 12,000 to 14,000 feet high — great north and south ridges, now terraced, and again strewn with cyclopean ruins. Winding through these ridges, and cutting perpendicular walls 3,000 feet high, are great ravines or canons, which debouch as valleys in the open plain. Between these ravines the strata are often worn and fretted

S/utTiintHiii G

away, so as only to leave pillars and buttresses, 5uiies, pointing towards the sky. Snow mantles around the higher peaks and terraces during the winter, taxmg, together with the fierce play of the winds, the ingenuity and enet of the miner, who even up there is burrowing and delving, if not to become rich, at least that he may live.

Turning now more particularly to the section, fig. so : i represenU the central granitic and gneissic rocks of the mountain chain. They are probably of Lower Cambrian age. The granite is often coarse, and easily decomposed. 2 shows the overlying slates and sandstones. The slates have undergone a good deal of change and hardening, which has destroyed any fossil remains they may have contained. They are crystalline.

Structure Of The Sierra Nevada. 53

and are both interbedded and intersected by porphyritic and serpentine rocks. They make on the surface a series of ridges parallel to the main axis of the great chaia They and the underlying rocks are traversed almost all along theu: strike by numerous quartz lodes, or ledges, as they are locally called, from their width, and from the fact that they stand above the edges of the surrounding strata. This is the case where the quartz is free from the oxides and sulphides of iron, and is consequently white in colour, and compact and hard in texture. Where these iron ores are present the quartz is coloured red, and the upper portion of the lodes is decomposed. Lodes of the latter character occur: more frequently in some of the more inland and southern States. Throughout these lodes gold is unequally distributed. 2A consists of a vast series of crystalline and metamorphic rocks, green, grey, purple, and blue slates, gneiss and gneissic rocks, which over large areas are changed into quartzite of an almost uniform texture of a bright and clean grey colour. This series has been proved to be the equivalent of the Potsdam sandstone, which is in its turn the equivalent of our Lingula and Tremadoc beds, or Upper Cambrian group of strata. It follows and flanks on either side the central range from British Columbia to Mexico, forming a belt on the western side of more or less continuity, and of a very great width. Everywhere throughout this vast extent of country gold is sparingly disseminated throughout the entire mass. At several great centres of disturbance, as at Mount Lincoln in Colorado, Bald Mountain in Montana, in Western Oregon, and in Northern California, it abounds in gash veins that contain the purest kinds of gold. 3 consists in the lower part of Devonian, and in the upper part of Carboniferous limestones, with their interstratified shales and sandstones. With the exception of iron ores, they form the uppermost limit of the metalbearing strata of the region, and, as we shall see, contain on the eastern side of the chain the great silver-bearing deposits of Nevada and Utah. Gold does, however, occur in the newer

' See also Engiruering and Affining Jmntal of New York, December 8, 1877, p. 144.

54 Metalliferous Minerals And Mining.

Strata partly in contact deposits and parflyin driftal and redeposited materials derived from the older strata. 4 are the Coal-measures, for the most part overlapped by the Triassic rocks, 5 ; but recendy workable coal seams have been found in the hollows and plains of Colorado, which is a matter of the first importance for this mining region, especially as the hillsides are cleared of timber. 6 are the Oolitic, 7 the Liassic, and 8 the Tertiary group of strata. Overlying the whole of these groups are the driftal deposits, 9, containing the redeposited gold. Good mining results have thus far been attained to a depth of 1,900 feet The highest hydraulic and underground mines of this region, and indeed in the world, are those of the Little Annie and Summit Rio Grande, County Colorado. The former are 11,000, and the latter 12,000 feet above the sea. There are only about no days when any outdoor work, save felling timber, is possible, and during three years July has been the only month in which snow did not fall The annual snow fall is 24 feet The latter mine is, notwithstanding its height, successfully worked, the quartz yielding gold to the value of 6/. per ton. Ordinarily the proportion of gold is less than this amount I have before me the statistics from seven ordinarily paying gold mines in California, the average production of gold to the ton of quartz from which is 2/. los.

The total amoimt of gold produced by the United States from 1848 to the close of 1874 was 250,000,000/., of which about three-fourths were produced by California alone. A continuous yield of three-eighths to half an ounce of gold to the ton of quartz is considered equal to profitable working.

Chapter Viii.

GOLD-ofUitmed.

Centnd America — Venezuela — Brazil — History of Gold Mbing in Brazil — Mines of Congo Soco and St. John del Rey — Analysis— Other Countries of South America.

Central America. — In proceeding southward, to describe the important gold mines of Brazil, I may notice in passing that gold was discovered in Nicaragua in 1850. It was worked in a rude manner until 1864, when an examination of the country was made by Mr. W. C. Paull. Shortly afterwards the Chontales mines were established, further south. Here, as in the region just described, gold is found in quartz veins that traverse metamorphic rocks.

Venezuela. — In Venezuelan Guiana, gold was discovered by Dr. Passard in the bed of the Yururari River, in 1849, and this place has been supposed to be the £1 Dorado of Sir Walter Raleigh. Doubtless, as these Central States and Northern States of the South American continent become more settled in their government, mining enterprise will develop. Gold, along with silver, is already being worked to a limited extent by an English company in Venezuela. Let us now pass on to

Brazil. — This is one of the oldest, as it is stiQ one of the most important, of gold-producing countries. Gold mining operations are chiefly conducted in the province known as the Minaes Geraes. This district lies in the southern part of the country, and is situated between the two great ranges of mountains that run in a south-westerly direction from the north-east comer of Brazil The district is about one hundred miles in length, having the towns of Villa Rica and St. John del Rey,

56 Metalliferous Minerals And Mining.

with the mines that cluster around them, in the south, and the mines of Gongo Soco in the north, the distance between the two groups of mines being about eighty miles.*

Gold was known to exist in the south of this region in the year 1543, when the Indians made their fish-hooks and personal ornaments from it. The first white man that found it was Antonio Rodrigo, who discovered it on the banks of the Riveao, a small stream that falls into the larger river since known as the Rio des Mortes, near the towns of St Jose and St. John del Rey. Rodrigo, dying shortly afterwards, was followed by his son, and he by the Paulistas, or people of St. Paul's, to which district he belonged. The Paulistas, fighting over their booty, killed each other in considerable numbers, and so gave the name of River of Death to the stream on whose banks they fought.

The banks of this stream soon became furrowed and burrowed by rude attempts at surface mining, and the quality of the gold obtained from this spot was long considered the finest in Brazil. North of the town of St. John del Rey is that of Villa Rica, which owes its name to the amount of gold obtained in its vicinity. The Paulistas here found gold that darkened in colour on exposure, owing to its alloy with silver. They called the mountain Ouro Preto, but on great quantities of gold being obtained they changed the name of the town that had sprung up to Villa Rica, the rich town. It was owing to the daring of the Paulistas that the discovery of gold was followed up and the district colonised.

For a long time the gold was only extracted from the clay, through which the rains from the mountains had filtered, leaving behind the particles of heavier metal The first mines were thus simple pits, called catas.' These were worked downwards until the gravel, or cascalho,* below, cemented together with the oxides of iron, was reached. This was broken by picks, and taken to the river to be washed. A step in advance, and one that anticipated the modem method of hydraulic mining,

See also Mawe's Travels in Brastil; Henwood's Metalliferous Deposits ; 'Reports of St. John del Rey Mines,* Mining Journal 1877-8.

Gold Mines Of Congo Soco. 57

was to bring the water to the gravel, and thus wash the gold on the spot, instead of carrying the gravel to the water. These works were called lavras.' Following this gold-bearing drift upwards, it was traced at last to the outcrop of the great lodes of ferruginous quartz, whence it had originally been derived. These, for some depth below their outcrop on the hillsides, were decomposed, and were readily worked by open trenches cut into them.

Beyond this, native skill and enterprise could not go ; indeed, the wonder is how, with their primitive appliances and little knowledge, so much gold was raised. Gradually the attention of English and German miners was attracted to the country; by slow degrees concessions were obtained from the Government, surveys were made, and operations of a true mining nature were commenced by the sinking of shafts and by the erection of a rude stamping machine made of wood. It was to work a concession on the Monro Velho estate that the English company, known as the St. John del Rey Company, was formed in the year 1830. The mines of this company have been successfully worked until the present time. This property was bought of the original adventurers, in 1725, for less than 20/. In 18 14 it yielded 43 lbs. of gold; last year its production was about 4,500 lbs.

It will help us the better to understand the position of the lodes worked here if we first consider the geological structure of the country, as this is illustrated further north at the mines of Gongo Soco, six miles SE. of Caethe. These mines were discovered by a solitary Portuguese, named Manuel Camaia, who worked the gold deposit with his own hands, and became rich. The thought occurred to one of his successors that he was only working the refuse of an imtouched body of gold, so he searched the mountain beyond, and was rewarded by the discovery of gold spread through a lode or bed forty feet wide. This discovery led to levels and shafts. The success that attended his efforts attracted more scientific and systematic miners, who, in the year 1825, tpok the name of the Imperial Brazilian Mining Association. I do not know the present com-

58 Metalliferous Minerals And Mining.

laCTcia] condition of these mines, but I observe that th are attiacdng attention.

Fig. 21 will illustrate the geological position of these mines, as well as that of the lodes of St. John del Rey.

At the base, as in North America, we have the usual granitic and gneissose rocks, i. These are succeeded by a series of clay states, i, which oflen become micaceous, talcose, and chloritic These slates contain great masses of quartz veins, and they are interbedded with thick quartzose flagstones. Above these there is a deposit of granular calcareous quartz, 3, in which are thin beds of talc and mica, that occasionally give place to ferruginous ores. These expand occasionally into

PtC II.— SiCTIOK DKA

), Calcareous gnnuli qimm. with Ihin bcdi of taJcoK slate. 4. lubiriie 5. JacotinM. 6. Conn, ft, GdoE Soco urifemus depcHit. 7. S!aln uiij porphyria. 8, Dolomiiic limoiond. a. Plus of Sl John del Key lodes.

thich ore deposits, of which 4, 5, and 6 are examples ; and which, as they form the auriferous deposits, will require a more detailed description. This metallic zone is overlaid by the massive homblendic slaty and porphyritic rocks, 7, which are succeeded by dolomitic Emestones, 8, in which magnesia is present to the extent of 35 per cent.

Gold is disseminated throughout the entire series. In the granitic rocks it is associated with palladium, and it appears in a crystalline form in the cavities. It also occurs abundantly in the veins a that traverse the slates, as at Sl John del Rey, especially as they cross the quartzose beds ; but here at Congo Soco the beds 4, 5, and 6, now to be described, form its great depositories. 4 is known as Itabirite ; it is from i foot to 6 feet thick. It consists of iron disseminated in mica slate. It

Itabirite, Jacotinga, And Canga, 59

also contains distinct quartz masses, and where these occur it contains the most gold. 5 is a bed called Jacotinga, from its resemblance in the variety of its colours to the Brazilian bird of that name. It is here composed of iron glance, earthy brown iron ore, brown manganese, flakes of talc, and layers of manganese. Its thickness varies from 6 feet to 30 feet, but several beds of the nature of those above and below, are occasionally interstratified with it It forms the chief repository of the gold, which is spread in crystals and particles throughout the entire bed. It is most abundant where the manganese is present, when it occurs in bunches and strings, the bunches seeming to succeed each other along and down the bed at an angle of 45 degrees to the north-west. Crystals of very fine yellow gold are found near the surface. This bed is overlaid by the 'Canga,' 6, which is a brecciated calcareous deposit, containing blocks of specular and oxidised iron ores, cemented by earthy iron ore. The Canga does not contain gold in profitable quantities although it is on record that in the year 1826-7 nearly 4,000 lbs. of gold were taken firom it The whole of the deposit formed by these three beds is of great thickness near the sure, but it thins downwards, so that at a depth of 70 fathoms from the surface it is only 8 fathoms thick. Partaking, as it does, of the nature of irregular bedding, it may again thicken in depth and probably increase in hardness.

Retimiing now southward, the deposit worked at Morro Velho is a true fissure vein. It occupies the position of the lodes at a, fig. 21. It is divided into two principal parts — the Bahu and Cachoeira. These again have branches, one of which is known as Gamba, and another as the Quebra Panaella. The lode has a general east and west direction, and so far has been most productive on the eastern half of its course through the property.

Fig. 22 represents a section of the strata and of the structure of the lode down to a depth of about 300 yards. From this section it will be seen that for nearly half of this depth the lode is constituted chiefly of quartz, but that in the lower half more slate enters into its composition. The inclination of the

6o

METALLIFEROUS MINERALS AND MININCr.

Stciim

Naturt qfLodi.

Mixture of slate and quartz. Ditto, with iron and copper

pyrites, quartz crystab and

spathose iron.

Massive quartz, with ban of slate and crystals of aixagonite.

Quartz iron pyrites and spots of

copper. Cavity with spathose iron.

Large masses of iron pyrites. Lode as above; 235 grains of gold per ton of ore.

Lode traversed by bar of slate. A horse of slate, with carbonate

of iron and arsenical pyrites

in vein.

350 grains of gold per ton. 400 grains of gold per ton.

Fig. aa.— Bahu Portion op Lode at St. John del Rey Mime.

Structure Of Lode At St. John Del Rey. 6 1

lode and its branches is varied by the bedding of the strata. Sometimes the lode follows the course of the bedding for some distance at their strikes down a joint ; at such points it is richer than usual in gold. Near the surface the sides of the lode are ragged, the jagged edges of the adjoining rock projecting into it, but in depth the sides become more even. When undivided the lode is about 14 yards wide, but its width varies, as shown in fig. 22. In a branch lode running parallel with the Bahu, from 150 to 200 grains of gold per ton of lode stuff were obtained within 40 yards of the surface. In the Cachoeira part, at from 200 to 220 yards, 218 grains to the ton were extracted. In the Quebra Panaella, 130 grains were obtained at a depth of from 150 to 160 yards. On the whole, the- lode does not deteriorate in depth, although there are points where it is not so productive j for experience shows that a mixture of iron pyrites and quartz makes the best matrix for gold : the metal being abundant where they are pretty equally mixed, but scarce where either prevails separately. Smce this description was written, the report of this mine for the year 1877-8 has been issued, and the following extract from the superintendent's portion of that report will afford an idea of the present condition of this remarkable lode : — As the lode was laid open on April i last (1878), it may be described as being divided into five parts, differing more or less firom each other, in length, figure, and component matter. The first, beginning on the eastern extremities and extending westward to nearly one-third of its entire length, is composed mostly of pure ore, but has for the greater part of its length a strip of quartz on its north side and of killas slate rock on the south. The next or second division, forming approximately another third of the length, is composed almost entirely of killas, with numerous shoots of ore striking across the slate rock. Following this on the west, in the third division is found a mass of pure ore of about a ninth the entire length of the lode, with a strip of quartz on the north side. In the fourth division we come to a mass of quartz of about the same length, with shoots of ore striking across it, and then in the fifth divi-

62 Metalliferous Minerals And Mining.

sion, at the extreme west, pure ore as far as excavated on each side.' 1

The production in the shallow workings years ago was about seven-eighths of an ounce per ton, and this was the rate of production last year. The estimated yield for the present year is about 55,000 ounces.

A full analysis of the gold from this mine gave the following results :

Gold 07*499

Silver 01 793

Lead 00-180

Bismuth 00-035

Copper 00*045

Antimony 00*030

Arsenic . 00*105

Iron 00*195

Mercury and loss 00*018

lO'OOO

The quality at different depths has been : from surface to 100 yards, 18 carats; 100 to 200 yards, 19 carats; 200 to 284 yards, 19 carats. The gold obtained from Gongo Soco mines has averaged 19 carats ; from Ouro Preto, 22 carats and of dark colour; and from Antonia Pereira, 23 carats fine. The total production of gold in Brazil at the present time may be estimated at 100,000 ounces.

Of the other countries of South America it may be summarily stated that their joint production of gold about equals that of Brazil In Chili, on the west of the Andes, we find gold mining rising in importance. At the mines of Catapillo the dressing of the refuse ores left by the Spaniards has yielded from 3/. to 4/. worth of fine gold per ton of refuse. The production of Buenos Ayres for the year 1875 was 4,000 ounces. Increased attention is being paid to this metal in Peru, and the mines of Arequipa are said to yield 4 ounces of gold to the cajon of ore. The mountains in which the gold mines are worked on the western side of the continent are a continuation of those of California, Nevada, and the North- Western States, and their geological structure is similar.

Mining Jourttalj June 29, 1878, p. 723.

Chapter Ix.

GOLD—conHnued,

Australasia — History of the Discovery of Gold— New South Wales- Victoria— Tasmania — Queensland — Productiveness of Reefs in Depth — Structure of Reefe— Gold Drifts — Proportion of Gold in Drifts.

Australasia.* — We will now cross the Pacific Ocean to the gold mining regions of Australasia.

New South Wales, — Count Strzelecki is said to have been the first to find gold in New South Wales, in the year 1839 ; but in deference to the wishes of the then governor, Sir G. Gipps, the discovery was kept secret, the colony being then a penal one. In 1841 the Rev. W. Clarke had also found the metaL In 1847 Mr. Clarke called the attention of the colonists to the auriferous character of the country, and from that date to 1850 he personally explored the larger portion of the goldbearing lands, over six degrees of latitude, from Queensland on the north to the Australian Alps of Strzelecki on the south, where firom the high ridges of Mount Kosciusko, 6,500 feet high, the land dips south into the province of Victoria.

In 1848 a survey of the country was undertaken by the Government, at the suggestion of the late Sir R. I. Murchison. In 1 85 1 the value of the diggings was proved by Mr. Hargreaves. The localities in which detrital gold was first found to any workable extent were on Summerhill Creek and the Lewis Pond River, in lat 33® N., long. 149® 15' E., in streams that run from the northern flank of the Corioboalas down to the river Macquarie, a river that flows northward and west-

' See also R. Brough Smyth, Gold Fields of Victona; The Yearly Colonial Mining Report; Murchison, SUuria; J. A. Phillips, Gold and Gold Mining*

&I. Metalliferous Minerals And Mining.

ward The metal was afterwards found on the Turon river that rises in the Blue Mountains. Discoveries continued to be made until, stretching north into Queensland and south into Victoria, a region i,ooo miles long from north to south was proved to contain gold in its driftal deposits. The growth of gold mining enterprise in New South Wales will be judged from the fact that in 1876 the total production of gold was 167,412 ounces, of the value of 613,190/. 7. 9//. In 1875 the yield had been 50,698 ounces more. Following close upon the discovery of goM in this colony, was its discovery in the more southern province of Victoria. In August 185 1 the governor informed Earl Grey that a large deposit of gold had been found in the colony at Clune's diggings, about 40 miles from Melbourne, in quartz giavel, and at Ballarat on the river Leigh, 75 miles from Melbourne, in fragments of slate rock. The most productive locality was Ballarat The total production of Victoria for 1876 was about 1,000,000 ounces, of which 400,000 ounces were from alluvial, and 600,000 ounces from quartz mining. This yield was 100,000 ounces less than that of the previous year. The growth of the colony as a mining country will be inferred from the statement that at the beginning of 1876 there were 1,101 auriferous quartz reefs actually worked upon, and 3,208 more were proved to be auriferous. About 42,000 persons were employed in mining, of whom 11,000 were Chinese. The largest amount raised in one year was 2,985,991 ounces in 1856. In 1879 the production of gold from alluvial mining was 293,310 ounces, and from quartz mining 465,637 ounces.

Tasmania. — The discoveries extended southwards to Tasmania or Van Diemen's Land, and this island contributed its share of the gold production of 1875 5° ounces from alluvial, and 3,800 ounces from quartz mining, making a total of 4,650 ounces.

Queensland. — If to the foregoing amounts we add 50,000 ounces from Queensland, we have a total of 1,272,760 ounces of gold as about the present annual production of the Australian continent and Tasmania. The proportion, taking the whole area from alluvial and lode mining being about equal

Structure Of Australasian Gold Fields. 65

The sources of this gold are to be found in the range of mountains that, at some distance from the east coast, extends from Cape York peninsula on the north, southward through North Australia, Queensland, and Victoria, and which, ramifying westward in the latter colony, reappear to the south in Tasmania, For gold, the first-named colony does not now require notice.

Balkrat gold fiId in recent lavas and drifts (z)

Cambrian and Cambro-Sikiriun, consisting of quartzose, sandy, slty, and meumoiphic

rocks.

Mount Ballant Goldfield (a)

With intrusive rock.

Mt. Maoedon 3,400 ft.

Ttaippean and granitic rocks.

Cambro-Silurian. Thick beds of quaxtzoae rock.

Silurian strata with WenlockfiMsils.

Caledonian Gold-field.

Cambrian and Cambn>> Silurian rocks.

Mt Juliet 4,500 fU

East

TVappeanand granitic rocks.'

Fig. 33.— Sbction of Strata thsougb thk Gold Districts of Victobia.

The general structure of these mountains, throughout their entire length, is shown on the section fig. 23, which is adapted from the Government survey of that country.

It will be seen that the geological structure of the country in the age of the gold-bearing rocks is the same as those of the countries we have already noticed. There are the usual fimdamental granitic and gneissic rocks, on which rest Cambrian and

F

66 Metalliferous Minerals And Mining.

SiluTian rocks in all their varieties, and irom which fossils, characteristic of the different groups of strata, have been found.

These older rocks are traversed by quartz beds and veins, locally known as reefs, that coincide for the most part with the strike of the beds. Fig. 24 represents an aurii'erous quartz reef, and the methods by which it is approached and mined.

Fig. 14,— Aoainitoua Gold Ritr. heai Ballaut. with MrrHaD or 1 1, Gnmidc iwfc. Qu*iu reef. 3, Sbifl. Slullaw woifciiiei with ladders.

The whole of the quartz veins and beds are not auriferous, for there are long stretches of barren reefs alongside those that are productive. In the latter the gold is usually associated with iron pyrites and titaniferous iron — the source of the emery that accompanies the gold in the alluvial deposits. The productiveness of the quartz or otherwise appears to depend chiefly upon the age of the quartz, and, as in Brazil, on the

Productive And Unpro;

presence also of iron pyrites. There is a good deal of quartz in Australia of younger age than that of the gold-bearing reefs lying near the base of the Coalmeasures. The following vertical section, fig. 35, will show the relative position of the two quartz rocks, and it will be useful when we co.ue to consider the copper deposits of the country. Mr. Keene' observes; 'There is a quartz at the base of the Coal-measures, in many cases of great purity, in which gold has been sought for in vain.'

The productiveness of the quartz reefs seems further to depend upon the nature of the strata with which they are associated. As a rule, the quartz ree are auriferous as they pass through homblendic or poiphyritic rocks, and cease to be so: when they enter schists, or the metal does not then occur in paying quantities. Diorite is also associated with the best paying lodes.

Mr. Wilkinson, F.G.S.,

Tz. 67

Upper CniJ.

' Quarttrfyji tai Saeiefy, tuL x

Metalliferous Minerals And Mining.

Government Geological Surveyor of New South Wales, has recently suggested an instance in which, as he thinks, a gold deposit has been derived from the conglomerates of the Coalmeasures, pointing to the inference that those conglomerates are themselves auriferous.* Fig. 26 is a reproduction of his own illustration as far as it concerns this idea, but an examination of it must, I think, show Mr. Wilkinson's inference to be erroneous. A geologist will see that the Coal-measures once extended right over the Cambro-Silurian rocks, d, so that the correct inference is that the gold deposit, e, must have been derived from the abrasion of those rocks, and formed prior to the deposition of the overlying Coal-measures. It has become exposed by the subsequent denudation of the

Fig. a6. — Illustration of Gold Drift at the Bass of the Coal-measures,

New South Wales.

A, Gardner's Hill. Basalt, soft, b. Thin layer of tertiary pliocene drift, c, Coalmeasures. D, Silurian sandstones, with shales and quaru ree&. b. Place of gold workings.

Coal-measures at the spot I am the more careful to point out this mistake, as I deem it, because I am sure that it is from similar errors, where a newer formation rests unconformably upon one much older, that statements concerning the deposits of gold in situ in the Upper Secondary rocks have been made concerning California. If, however, Mr. Wilkinson only intends to show an auriferous drift of Carboniferous age, no objection can be offered to the endeavour.

The intimate structure of one of the smaller quartz veins containing gold is shown in figs. 27 and 28, which I have adapted

Annual Report of the Department of Mines, New South Wales, for Uie year 1876, p. 166.

DETAILED STRUCTURE OF COLD QUARTZ VEINS. 6g

from an illustration by Mr. Richard Daintree, F.G.S,' The gold is represented by the dark lines in the centre ; the quartz on

Fio. IT.— Showimi: ti

either side is barren of gold, which seems to have been among the last substances deposited in the crack, or the gold may have

I 'On Certain Mode* of Occurrence of Gold in Australia,' R. Dnintree, T. G.S., Quarterly yowHoJ of the GtohgicaiSMiity, Alteon 187S, p. 43S.

70 Metalliferous Minerals And Mining.

been deposited afterwards in a subsequent reopening of the crack. Besides occurring associated with pyrites in granite rocks, gold also occurs disseminated in pyritous diorites, in pyritous felbites, and also in pyritous quartz and calcspar veins, usually well defined, wide, and persistent, by which these rocks are traversed, and into which the disseminated mineral has been mechanically and chemicaUy gathered

The 'reefs' are productive to a great depth. In Victoria about thirty mines have reached a depth ranging from i,ooo feet to 1, 800 feet The Newington Mine is 1,940 feet deep. Sixty-five tons of quartz, mined from a depth of 1,060 feet, gave 8 ounces of gold to the ton ; but this must have been selected quartz. The impression has prevailed lately that quartz does not, as a rule, pay for mining at a greater depth than 1,000 feet Possibly this idea, like many before it, may vanish before increasing skilL The proportion of gold to the ton of quartz crushed varies considerably, as the following particulars, relating to 1876, will show: 11,500 tons from Stawel, Victoria, obtained at depths varying from 430 feet to 1,060 feet, gave from i oz. 3 . to 5 ozs. 14 . to the ton ; 5,890 tons from Sandhurst, from depths of 500 feet to 1,000 feet, gave from I oz. 1 4 . to nearly 2 ozs. per ton ; South Clunes Mines gave from 2,171 tons, 8 . 9grs. per ton; and Port Phillip Colonial Gold Mine worked 4 . 8 grs. per ton at a profit In the third quarter of 1875, 259,997 tons of quartz crushed in Victoria, gave an average of 12 . i3igrs. ; in the first quarter of 1877, the average yield was 10 . 17 grs. The average yield may therefore be taken at 11 ., an average that seems to be pretty constant, for the proportion per ton from 5,811,669 tons 9 . of quartz, crushed during the ten years ending 1868, was 11 . 12-37 grs.

As elsewhere, the earliest discoveries and works were made in the drifls that fill up the valleys and cover the plains that are spread out at the feet of the mountains, and still, as we have seen, a large proportion of gold is derived from this source. We shall gain an idea of the structure and composition of these drifts by a perusal of the following detailed sections :

Gold Drifts Of Australia.

Sections of Drifts

In Austraua.

GaUen Rivers.

suigiia.

Uppermost drift. EUiog tip hoL

Uppennost drift, fiUing np hol-

lows and eicsiont in tbe diiftt

lows in the drift below, gold

below, and gold bearing.

bearing.

Upper Basalt (ocic, 25 feet to 30 feet.

"

Upper Basalt rocK, 49 feet

Pliocene eravel, gold bearing,

Sandy grits (FHocene), gold

50 feet Id 60 ieeL

bearing, 10 feet to 15 feet.

Absent.

Upper ConOline Limestone, ijfeeL

S

Absent.

S

and fossils. J Sandy Limestone, with n fossils.

Absent.

Miocene grayel, not prodactive,

Rounded quarti pebbles and hard

the &1k bottom of mineis.

40 feet

with giavels and boulders, 90 feet.

S

Thin bed of drin-cUf, with gold.

Lajrer of clayey drift, with gold.

Cambrian Strata.

Cambrian sirau.

One or more members of the series, as shown in the complete Steiglitz section, is frequently absent, as shown in the diagram sections, figs. 29, 30, and 31, which are adapted from Mr. R. Brough fcdV

Smyth's complete and valuable work.

When the recent drifts that lie on

the surface are worked for gold, the operation is called surface or shallow mining ; but the operations by which the Dft

deeper and older auriferous drifts are reached, are known as deep sinking This lowest auriferous drift lies irame*

diately upon the eroded surfaces of the AuHiirout drift

usually upturned edges of the Cambrian ,l!™"' "" "

strata. They fill hollows and old river da.ujts. courses along the surface of these beds, which are often followed for miles. These long troughs and river-courses are

73 METALLIFEROUS MINERALS AND MINING, called ' leads,' and fig. 3a will give an idea of their position as

AunliiQUl drift

SdiiMoH bottom

FlC Jl.— SiCTIOH or THE OLDIll DnlFTjIL GoLD DiPOSlTS HEAR BaLLAXAT.

Sale: Her. i" lo chiim ; VeiI. i" ° feel.

Diili. t, Buill. c. Black uid nd clayi. Bauli. t, light coloaml cluyl.

/, BuhIi. 1 1 T, Auriferous drift.

Ihey occur in the neighbourhood of Ballarat, as well as of the

Gold Drifts Of New South Wales. 73

way in which they are often approached by adit levels, and connected by levels driven through the intervening strata.

'g- 33 represents a similar deposit on the Macquarie River, New South Wales. It is interesting by way of comparison with the sections &om Ballarat, as showing the newer auriferous drift approached by a shaft, and also the contrast between the present river valley of the Macquarie and the ancient watercourse.

A neighbouring section shows the basalt, which, as in Victoria, spreads over the older drifts, and has helped to preserve them from denudation. The shaft passes through

Loam sand Bod clay 40 feL

Vesicular basalt 130 feet.

Light pebble drift and gold wash, cemented ia\

places with oxide of iron and iron pyrile*, I ,

containing fragments of wood xod coaly shale, f Tfae drift yields 5 . to the load . . )

The gold is found in these drifts in grains and one of the latter reaching 600 ounces. In 1876, 57414 tons 3 . of drift washed in Victoria, gave an average of a2-6j grains per ton. 35,938 tons of cement or drift caked together were crushed, and gave an average of 4 . 13J grs. per ton.

74 Metalliferous Minerals And Mining.

In New South Wales the average yield of gold per ton of drift for 1875 5 . 9*58 grs., but it is explained that this high average came from 58,081 tons of selected wash dirt The average from 172,630 tons of drift in 1876 was i dwt 23-14 grs.

f

Chapter X.

GOLD — continued,

NcwZealand— HKtory— Gold mxihi— Gold in Drifts — Africa— Gold Field of Leydenbeig — India — Philippine Islands — Aruba Island — Concluding Remarks.

New Zealand. — Returning eastward a little way we find a similar range of mountains to those of Australia running N. and S. down the two islands of New Zealand. The section, fig 34> adapted from one of Dr. Hector's,' the Government

Pstnbroko

Peak

Milibrd

Soand

QreenaCoDe Pm

CMtern limit of r:

eiyiUlline Wskatlpn Shotorer Black roeki Lake River Peak

Posltloxk or the Gold Fleldi

Up. Clntha ]>iinvtn Flalni Mti.

Position of theold Flddi

Mannherlkla River

Lammerbaw Up. Tluerl Kakanul

Range Tnapeka Plain Mta.

Hone Ranges Moeraki

If f 6 7

Fig. 34.--SKCT10N ACROSS the Province of Otago.

X, Gneissic granite. 9, Dykes of cUorite, &c. 3, Granitoid, porphyritic, and syenitic rocks,

Quanzites, slates, felstones, serpentine, and marble. ) ri>.ij 1

5, Grey, blue, and contorted foliaceous schists. ] <d-beanng strata

Sandstone and porphyritic rocks. 7, Carbonaceous sandstones, with brown coal. 8, White ara, with fossils and tufaceous rocks and basalt. 0, Ancient lake deposits, with brown coaL The great gold drift.

geologist for that colony, gives a detailed description of the gold-bearing rocks, with their associated strata, together with the gold-bearing drifts.

" Dr. Hector, Quarterly Journal Geological Society vol. xxi. 124,

y6 METALLIFEROUS MINERALS AND MINING.

Up to the year 1857 there was no gold mine in New Zealand, but in the twenty years ending last year, no less than 8,038,571 ounces of gold had been obtained. The yield for 1874 was 14,306 ozs. 17 .

The quartz occurs both as filling up fissures and as irregularly stratified beds. Both the lodes and beds are contained in a series of strata (4 and 5 of section), which are divisible into three parts : first, the upper grey arenaceous slaty rock, which does not contain much quartz, either in veins or beds ; second, the middle part, about 200 feet thick, which is made up of soft blue micaceous slates, traversed by small quartz veins of a decomposed nature, especially near the surface. This is supposed to be the source whence the detrital gold of the Western, or Lake Gold Fields, has been derived. Thirdly, the lower part, made up of clay slates, often chloritic and contorted and fohated with quartz, especially in its lower portion.

The quartz laminae are concretionary in their structure, of a bluish colour, and homy in appearance. Besides the gold found in the quartz lodes and beds, the metal occurs segregated in the interstices of the contorted schists, but it is not worked in situ.

One of the richest gold-bearing districts is that of Coromandel, in the northern island, near Auckland, and among the mines may be mentioned that of Kapanga, where good gold is found in a quartz vein, four feet wide, at a depth of 300 feet from the surface. The yield of gold from some of the auriferous reefs is as much as i ounce to the ton, but the average is considerably less. The drifts, like those of Australia, are both recent gravel sands and ancient driftal deposits. The latter are in places like old lake deposits, in which gold is associated with brown coaL They follow the range of the mountains firom north to south.

Retracing our steps to the Old World, I will briefly notice the recently discovered gold deposits of South Afirica.* A range of mountains extends at some distance inland along the eastern

See Dunn, Quarterly Journal Geological Society vol. xxxiii. p. S79.

South African Gold Field.

coast of Africa, from the Red Sea to the Cape of Good Hope. NE. in their ramifications through Arabia they form the depositories of the gold of Midian, to which Captain Burton has just directed attention. It is probable that ultimately gold, both in situ and in driilal deposits, will be found all along the course of this range ; but at present the gold fields are confined to the portion that lies between the Zambesi on the north, and Cape Colony on the south, in the north part of the Transvaal, the chief mining operations being grouped aroimd Leydenberg, laL 40' S., and long. 31° E.

Fig. 35 will afford an idea of the geological structure of the district, which is of the usual kind, underlying granites, gneiss.

Fig. 35.— Section through thb Lbydbnbsrg Goldpibld, South Atrica. Horizontal scale milet ; Vertical z"s4,ooo feet.

a. Quartz rode, Fissile sandstones, Soft pink sandstones. At, Pink, blue, grey, and brown sandstones, much jointed, k, Cherty limestone. U, Limestones. lilllll. Greenstone.

and greenstones, succeeded by laminated mudstones, white and red quartz, bedded rocks, calcareous strata, with thin layers of quartzite between the bedding and quartz breccia, like quartz rock shattered, and the cracks filled with newer quartz.

In 1864 Dr. Mann found gold in a high granitic tableland, forming the watershed of the rivers Lipalule and Limpopo, in which there were numerous traces of ancient mining. Mr. Bains also foimd some considerable clusters of reefs near the Zambesi. Quartz reefs were also found 200 miles NW. of Leydenberg, some of which were worked by Englishmen. The ancient mines seem to have been worked on the reefs as open quarries. There were recently eleven mines at work in the

78 Metalliferous Minerals And Mining.

quartz rocks, and a description of one of these will illustrate the general character of the rest The Erstellung Mine is situated near Marabastadt, in lat 5' S., and long. 55' E. The strata are composed of chloritic and steatitic schists, which dip at an angle of about 80° N. These schists rest on gneiss, and are overlaid by the gold-bearing rocks of Leydenberg. The principal reef worked, the Natalia, is about three feet wide, and follows the bedding. The gold is sprinkled throughout the quartz, and it is also accumulated in the cavities. The yield of the reef is stated at i ounce of gold per ton of quartz. The reef is accompanied along its course by dykes, probably beds, of diabase, and it is crossed by dykes of dolerite.

At Leydenberg the gold occurs botii in flat beds of quartz, and also in strings or veins interbedded with and intersecting the limestones 1 1 of the section.

The principal locality where driflal gold is found in South Africa is at Pilgrim's Rest Creek, which is thirty miles due west of Leydenberg. The creek is about three miles long, and flows west into the river Blyde. The drift in the creek is from five to twelve feet deep. At the top it consists of fine alluvium ; this. is succeeded downwards by clay, in which are imbedded pebbles and fragments of the adjoining rocks. Below this, and resting upon the solid rock, is the bed of auriferous drift, about one foot thick. The gold is found in grains and nuggets, the whole of which are rounded and coated with oxide of iron. The quality of the gold is valued at fi'om 3/. lor. to 4/. per ounce. Diggings are also worked at Mac Mac Creek, where the drift is made up of slaty sandstones and calcareous fragments. There is an absence of the great boulders that rest in the auriferous drift of Pilgrim's Rest The gold is scarcely equal to that of the latter place, and it occurs in finer grains. The yield of gold from South Afirica is estimated at the value of 60,000/., but it is believed that the total amount reaches nearly double that sum.

Other Countries. — Gold is found imder similar conditions in other countries. The Shah of Persia is said to have remitted half the taxes of the subjects of the province of Zingan in

Concluding Remarks. 79

that empire where gold has recently been found. In North Western India detrital gold is found in the sands of River Ramyunga, which has its source in tle Himalayas ; also in the gravel of the Alukunda and the Pindur, out of which gold was formerly washed by the natives. It has also been observed in quartz veins in granite at Kurmaon and Gurwahr. In China it is worked and is almost exclusively in the hands of the mandarins, to whom the miners are obliged to sell gold at 42s. for every loox. of its value. From the difference of 5&r. the mandarins pay a tax of I oj. to the Government and pocket the difference.

The Philippine Islands contain gold which has not as yet been much worked by European enterprise.

Aruba Island, one of the Leeward Islands of the Caribbean Sea, has both auriferous quartz reefs and drifted deposits. In 13 . of gold, valued at 2/. 12s. per ton. Recently the metal has also been found in New Guinea.

Concluding Remarks, — From the foregoing descriptions it will be seen that gold occurs in rocks of the same age and under similar conditions all the world over. That for the most part gold-bearing rocks lie below the Carboniferous group. That the general horizon of the most productive rocks lies at what in North Wales is the junction of the Lower with the Upper Cambrian, the horizon of the Lingula flags and the beds below. That schists or slates of a steatitic, talcose, and chloritic nature, with granitic and greenstone rocks of the same age, are the best depositories of gold. That it is finely and sparsely disseminated throughout the whole of the above rocks, but segregated in quartz beds and veins. That in quartz it is most abundant where iron pyrites, titaniferous iron, and other ores of iron prevail That the idea of twenty years ago, that gold was thrown up to the surface of rocks and died out in depth, is not correct, as, indeed, it might have been expected it was, since, theoretically, no present surface of rock was the original surface. Practically, and as a matter of fact, gold is now profitably worked to a depth of 1,000 feet and more. That the continuation of gold in paying quantities downwards,

80 Metalliferous Minerals And Mining.

depends more upon the nature of the rock traversed by quartz lodes than upon the depth itself. Finally, that it is probable that in Africa, India, Persia, and everywhere where the great mountain ranges composed of the rocks described come to the surface, gold in situ will be found abundantly, as explorers pay the same attention to them that they have done in California and Australia. All along these mountain ranges detrital deposits containing gold may also be found. There is, therefore, no ground for the fear sometimes expressed that the world's gold supply wiU fail, especially if some simple invention be conceived by which the sea-sand of the shores of auriferous countries, like the black sands of the Califomian and Oregon coast, shall be made to yield readily and cheaply their contained particles of gold.

8z

Chapter Xi.

Silver.

General Characteristics — Its Ores — Silver in Russia, Austria, Bohemia, and Saxony — Description of the Mines of the Erzgebirge — Hanover and Brunswick — Nassau — France, Spain, Norway, and Great Britain.

Next to gold, silver is the most useful and precious of the metals. Its hardness is described as 2*5, and its gravity as 10*3 to 10*5. In hardness it is therefore the same as gold. It is less malleable than gold, the thinnest leaves into which it can be beaten being the i6o,tooth part of an inch thick. In colour and streak it is silver white and shining, but is sometimes tarnished yellow, red, brown, and black .

Silver occurs in nature in a native form, in which it is usually alloyed with some other metal : sometimes containing as much as 10 per cent of copper and 16 per cent, of bismuth. It also occurs, and more abundantly, in a mineralised form, as ore, in which it is associated with arsenic, bromine, iodine, selenium, and sulphur, and also in combination with various acids. The following are the principal of these combinations :

Ores Of Silver.

Silver Glance. — Sulphide of silver, composed of 87*04 parts of silver and 12*96 parts of sulphur. This ore has a metallic lustre, is of a dark grey colour, and has a shining streak. It is the common and most valuable ore of silver. The rarer varieties of this ore, in which the silver and the sulphur are mixed with other minerals, are :

I. Brittle Silver Ore. — Composition : Silver 68*5, sulphur |6'4, antimony 147, and copper 0*6.

o

Ruby Silver.

Sz METALLIFEROUS MINERALS AND MINING.

2. Antimonial Silver, — Silver 77*0, antimony 23*0.

3. Polybasite, — Similar to brittle silver ore, but containmg arsenic and copper. .

4. Miargyrite, — Silver 36*5, with antimony and sulphur in larger proportions than British silver.

5. Dark Red Silver Ore, — Silver 59*0, with antimony and sulphur, coloured to black with a red streak.

6. Light Red Silver Ore. — Silver 65*4, witli arsenic and sulphur. Colour cochineal red

7. Euchairite. — Films of silver and copper, containing selenium.

8. Telluric Silver (Hessite). — Silver 62*8, and tellurium 37*2, said to be found only in Siberia. Contains sometimes a considerable proportion of gold.

9. Xanihocont, — Silver 66 "2, with sulphur and arsenic. Chloride of Silver, or Horn Silver. — Composed of

75 parts of silver and 25 parts of chlorine, but usually contains a small quantity of the peroxide of iron. It is grey in colour, and of a homy or waxy appearance. In a flame it emits acrid fumes. It is the common ore of the Mexican and South American mines. Its varieties are :

1. Bromic Silver, — Containing an admixture of bromine.

2. Iodic 6i7z/.— Containing an admixture of iodine.

3. Embolite, — Composed of silver 67, bromine 20, and chlorine 13.

In describing the quality of silver, it is said when perfectly pure to be silver of twelve pennyweights. If it contains one twelfth part of alloy with other metals it is silver of eleven pennyweights, and so on downwards in the scale of quality.

Following the plan adopted in the description of the localities and modes of occurrence of gold, I will begin again in the East, and will notice the chief mining localities westward.

Russia. — On the east of Lake Baikal, in the southern part of Central Siberia, are the mines of Nirchchinsk, which are worked in a crystalline limestone for a lead ore that is largely

Silver Mines Of Hungary. 83

charged with silver. Westward along the same latitude are the Kolivan mines of the Altai mountains, where silver ores are obtained from Cambro-Silurian schists, interstratified and intersected with porphyritic rocks. The silver ores are here associated with those of copper, gold, and lead. The production of the whole empire may be estimated at 60,000 lbs. troy.

Austria has long been a great sUver-producing country. It will be convenient to describe first the mines of Hungary, and secondly those of Bohemia.

Hungary, — The mining region of Hungary is usually divided into four districts : i, Upper Hungary, around Schmol nitz ; 2, Lower Hungary near Schemnitz, Kremnitz, and Neusohl 3, Nagbanya, on the western limits of Transylvania and 4, the Banat, around Oravicsa and Szaska. The mines of Lower Hungary and the Banat are best known. The lodes of Schemnitz and the neighbourhood traverse a boss of greenstone porphyry, in which they are productive, but cease to be so when they enter the trach3rte that overlies and surrounds it* They run from east to west They are nearly parallel to each other, firom about 1,000 to 2,000 feet apart There are seven principal lodes in one group, the chief one of which — the Spitalberg — extends a known distance of three miles, and is from ten to twelve feet wide. Silver prevails at the western end of this lode, galena at the eastern end. At the Windschact a depth of 330 yards was attained on this lode, where bunches of silver ore were found scattered throughout the gangue, which was laiigely composed of felspar.

Another lode, the Biebergang, was woiked to a depth of about 1,300 feet, and for a length of three miles. It 3delded an immense amount of silver, but in this and in the other lodes beyond this depth the silver gave place to galena, which was less and less argentiferous.

The mining district of the Bamt, to which a reference has been made already, forms an irreguUkr oval area, whose longest axis is north south. It has a base of granitic and gneissic

1 See also Mining Journal 1877, pw 795, et seq.

G2

84 Metalliferous Minerals And Mining.

rocks, as seen in fig. 17, and in fig. 36, on which rest felspathic and porphyritic rocks. Sometimes limestones rest in the troughs between the north and south ridges, and frequently these ridges are thrown up in the midst of altered cretaceous limestones, which abut against them. Most of the mineral . deposits belong to the group of contact deposits, and are usually richest in mineral near the surface. The minerals found are veiy various — gold, silver, copper, lead, zinc, and iron. Most of the minerals seem to have been deposited as

sulphides, which character they retain in depth; but near the surface, through contact with the atmosphere, they have become oxidised. As a. rule, the deposits become poorer for minerals, both as to quantity and quality, southwards.

Silver is found, in a group of mines near Dognacska, associated with lead and copper. At the Barbara Mine the ore is dressed into three qualities: (i) Oxidised leadores, containing 20 per cent of lead and 10 ounces of silver to the ton ; (a) galena, with 34 per cent of lead and 16 ounces of silver to the ton ; (3) cupreous pyrites, containing 1 per cent, of copper

Bohemia And Saxony. 85

and 18 ounces of silver. These mines are worked in deposits that lie between a dyke of syenite and overlying limestone; the ore- is usually found on the upper side of the deposits, under the hanging wall of the limestone. At the old mine of Simon Judas, fig. 36, the ore was an argentiferous copper. The ores were copper glance and copper pyrites, which, in the upper part of the min, contained 30 per cent, of metalhc copper and 18 ounces of silver to the ton of ore, but the ores became so poor in depth as not to be worth following downwards. At another mine, the Jupiter, the gold associated with mundic contained 15 per cent, of silver.

Bohemia and Saxony. — Crossing now to the north-west of Austria, we reach the range of the Erzgebirge, or Silver Mountains, that divide Saxony from Bohemia.

This is the classic ground of German metalliferous mining. Here it was that Werner taught, and here he started that controversy between Aqueous and Plutonic forces, and the part each has played in the history of the earth, which even now, after the lapse of a century, disturbs and divides geologists. Here, too, as the result of careful plodding work, the Germans have attained the van of scientific mining.

About the year 1170, a Bohemian labourer travelling near Freiberg, then covered with a vast forest, sat down to rest nimself on a stone by the wayside. He saw a stone lying at his feet, like others he had before seen in the Hartz. He carried a part of it with him on his way, and as soon as he could he had it tested. It proved to be galena, rich in silver. He returned with some comrades, and searched for the lode from which he supposed the stone had been derived, and was successful. Some years afterwards, the Duke of Brunswick having offered an outrage to the wife of an officer of the mines in the Hartz, the miners revolted, deserted the mines, and following as a leader one of the discoverers of the Freiberg lode, established themselves in a village near it, which they

' Daubisson, Des Mines de Freiberg; Weissenbach, Gangverhdltnisse aus dem sachsischen Ersgebirge; idH,, Ueber Gangformation ; Percy, Metallurgy of Lead,

86 Metalliferous Minerals And Mining.

called Christiansdorf, which afterwards came to be called Freiberg. The mines grew in number and in production, enriching the miners, and also the royal owners of the soil The town became prosperous and rich. It, with the whole district, suffered in the different wars, especially during the Thirty Years' War; but it again prospered, and became famous for the school of mines, of which Werner was a distinguished professor. Even now, although some of the mines are exhausted and others are worked at great depths, it is the chief mining centre of Europe.

The greater proportion of silver produced by Saxony and Bohemia is obtained from the Erzgebirge. Fig. 37 shows the general structure of this range of mountains. The central boss or ridge of these mountains is composed of granite, i, which in its upper portion passes on both sides into gneiss 2 2. The gneiss

Cms

Fig. 37. — Diagram Section across thb Erzgsbirgb.

is succeeded by a series of micaceous slaty rocks, 3 3, which in their turn are covered by a succession of clay slates, 4 4. Then come the Carboniferous rocks, 5 5, and the Permian, 6 6. The succession of the strata is the same on both sides of the range, but the Bohemian side is the steepest

Between the beds of gneiss there are beds of quartz, together with bedded and irregular porphyritic rocks. The micaceous and clay-slate beds also, as in this country, contain many beds of porphyry, trap, and limestone, together with beds impregnated with iron pyrites. The granite is composed of fine grains of felspar, quartz, and mica, the latter giving to it a somewhat leafy texture. It is also traversed by thin basaltic dykes and quartz veins, and, as may be supposed, it forms the highest peaks of the range. The gneiss is formed of white felspar, quartz, and mica, running in sinuous layers. Besides

Lodes Of The Erzgebirge. 8/

these, its regular constituents, it contains in places schorl, tourmaline, and earthy and steatitic substances — the latter probably decomposed felspar. The gneiss varies in hardness ; where the quartz prevails it is as hard as granite, while towards the surface and near the veins it is tender, and offers but slight resistance to the miner. It is regularly stratified, and the dip of the beds varies considerably. Close to Freiberg it is nearly horizontal ; to the north its ridges are parallel to the mountain range; to the south the dip inclines south-west Interstratified with the gneiss and slates, which I have already described, there are, as I have said, beds of compact felspar, hornblende, calcareous matter, and layers of pyrites.

The strata described are traversed on the Saxon side of the range, and within no great distance of Freibeig, by about nine hundred lodes, which are classified into four groups, each group having more or less affinity with the rest.

The First Groups sometimes called the Precious Quartz Group, consists of quartz veins. It comprises about 150 lodes, which range from six inches to one foot in width, and which have a direction NNK by SSE., with a dip or inclination of 70 to 80 degrees to the west. The quartz is often intermixed with fragments of the adjoining rock, and is sprinkled with pyrites. It contains druses and cavities, in which, and in nests irregularly distributed throughout the lodes, lie the metalliferous minerals. The silver ores contained are silver glance, polybasite, miargyrite, stephanite, and pyragyrite, together with arsenical pyrites and antimonial silver ores. These lodes are well developed near Braunsdorf, where they are richest in a dark carbonaceous slaty rock, and become poor as they pass into the micaceous.

The Second Group consists of brown spar veins, and is also known as the Precious Lead Group. It numbers about 340 lodes, which, besides containing quartz, are charged with diallogite and the spathic carbonates, chiefly brown spar. The metallic ores are galena, rich in silver and blende, with iron pyrites. These minerals are often beautifully arranged in layers. In the cavities are also silver ores and lumps of native silver,

88 Metalliferous Minerals And Mining.

one of which has reached one hundredweight These lodeb have a north and south direction, and dip to the west.

The TJiird Group is composed of lodes, whose matrixes are the oxides and carbonates of iron mixed with fluorspar and sulphate of baryta. This is also known as the Barytic Iad Group. It numbers about 130 lodes, which are occasionally of great size, and present some fine examples of the banded structure of veins. Lodes of this group traverse the higher Carboniferous and Permian groups of strata, and they are strongest and contain most silver ores north of Freiberg.

The Fourth Group prevails east of Freiberg, and consists of veins firom two to three inches wide, of which there are about three hundred. The gangues are carbonate of lime, sulphate of baryta, and fluorspar. The metalliferous ores comprise galena, blende, copper and iron pyrites, mispickel, and the usual silver ores. The galena contains 10 to 60 ounces of silver. It is also known as the Pyritic Lead Group. These, lodes become, as at the Jungehohebirke and Morgenstem mines, cupriferous when quartz prevails as a matrix, and then the metalliferous ores are the red and black oxides, and the blue and green carbonates of copper with copper pyrites, vitreous copper with silver and purple copper ore. These copper ores contain about 10 ounces of silver to the ton, and a slight proportion of gold. The average proportion of silver in the galena of this region is 49 ounces. In ordinary vein stuffs 16 ounces to 30 ounces to the ton of ore is the varying proportion.

On a morel limited scale this description of the Freiberg district will apply to the Bohemian side of the range. The average depth to which the lodes have been worked is 1,500 feet, and at this depth they are persistently rich in ore.

Observations made during a great number of years seem to point that the productiveness of lodes depends among other things on the power of the enclosing strata to conduct heat and electricity, and hence upon their composition and density, so that certain rocks are called carriers ' — the moderately dense slates and gnessic rocks possessing the qualities.

Hanover, Nassau, France. 89

The Rothschonberg tunnel just completed is nearly twelve miles long, and will drain these mines to a depth of 1,700 feet

The annual yield of silver from the Bohemian side of the range may be estimated at 30,000 marks. The total production of Austria is about 110,000 marks. The annual production of Saxony from the Erzgebirge is about 60,000 lbs., which has been the average for a great number of years.

Hanover and Brunswick. — Another great centre of German mining industry is the Hartz range of mountains, the strata and lodes of which wiU be more fully described when we come to speak of lead. It is only necessary to observe further now that the lead ores of this region are among the richest in Europe for silver. The annual production of the district may be estimated at about 30,000 lbs.

Nassau.* — Passing down the centre of Europe, we cross the highly-mineralised Htde duchy of Nassau, whose production of silver is equal in value to 30,000/. A good proportion of this is obtained 'from lead ores, which contain from '003 to '006 per cent of silver. In some instances the silver reaches i per cent of the ore. Clean ores, free from impurities, are found in the breccia of lodes. Silver ores proper also occur in quartz lodes near Holzappel ; and spots, plates, and dendritic incrustations of silver occur in lodes filled with quartz ; and brown ironstone and covering lead ores near Oberlahnstein.

France. — Passing from Germany to France, nearly all the lead-producing mines give silver, and special mention may be made pf the following principal mining centres where silver is produced : i. The ddpartement d'Isfere, des Hautes-Alpes ; 2. dpartement du Puy-de-D6me, in Central France ; and 3. d- partement des Basses- Alpes, du Var, and des Alpes-Maritimes. The total amoimt of silver produced in France amounts to about 50,000 kilogrammes.

In the department of Isfere, south-east of France, silver was first found in 1767, by a goatherd who was looking for his kid,

' Odemheimer, Das Berg- und HuUenwesen im fferzogthum Nassau, Cailloux, Mines Mitalliques de la France ; Henwood, MetaUifenms Deposits.

90 Metalliferous Minerals And Mining.

in Chalanches d'Allemont, a spur of the great Alpine chain. The axis or foundation of this part of' the Alps is a coarse granite, that changes occasionally into gneiss, both granite and gneiss changing occasionally into fine-grained crystalline masses. They are overlaid by hornblende slates, into which the gneiss graduates. The general direction of the beds is north and south. Traversing these rocks are eight principal lodes, which run at varying distances from each other east and west They have a dip of 50 to 70 degrees, chiefly to the north, but varying along their course. These lodes range in size from 6 inches to 2 feet 6 inches wide. They are filled up largely with the materials of the rocks they traverse, but they also contain calcareous spar, felspar, quartz, and hornblende, with smaller proportions of asbestos, chlorite, epidote, mica, and talc Silver is found in these lodes in a variety of forms — native, mixed with antimony, with antimony and sulphur, and with sulphur and salt The ores are most plentiful in a matrix of earthy brown iron ore, and also where the lodes are charged with calcareous spar, chlorite, and asbestos. Other metallic minerals are associated with the silver, as copper, lead, nickel, and zinc, with cobalt, and a variety of earthy minerals. In the department of the Puy-de-D6me, the proportion of silver to the lead ore is 400 grammes to 100 kilogrammes. The lead ores of Brittany, as well as those of other mining districts, contain, as I have said, more or less silver.

Spain is an old silver-prodiicing country. The metal is not found alone so much as associated with lead. The strata and the lodes in which the latter occurs will be described under the head of that metal. According to Strabo, 40,000 men were formerly employed at the mines of Carthagena, and the daily returns of silver amounted to 20,000 drachmas (8j//.), or 911/. 7. sterling. In 1839 a lode of argentiferous galena was discovered in the same neighbourhood, which gave 1,800 arrobas,* or about 20 tons of lead ore per day. The lead ores of the Sierra de Gador only give 2 ounces of silver to the toa The galena of

I arroba 25 lbs.

Silver Mines Of Kongsberg. 9I

Linares, in the province of Jaen, gives about 9 ounces to the ton. The galena of the Jaroso vein of the Sierra de Almagrera, between Carthagena and Almeria, is exceedingly rich in silver, yielding as much as 130 to 180 ounces to the ton; while that 9f the lead ores of Homachos are said to give 100 ounces to the ton. The silver is most abundant in the upper decomposed parts of the lodes, where it is combined with sulphate of lead and the hydrated oxide of iron.

As a rule the lead from the slaty rocks of Spain is richer in silver than that derived from the limestones. The total annual production of silver in Spain may be estimated at 120,000 lbs.

Norway. — We have retraced our steps eastward somewhat in visiting Spain, and now we must take a long stride to the north-west margin of Europe, where, in the south of Norway, we find the most celebrated silver mine of Europe, that of

y

Fig. 38. — Diagram op thb Silver Fahlbands at Kongsbbrc, Norway.

I X 1 X, Fahlbands in gneissose and micaceous slates. 2 a a a, Veins. Dark shadings

rich ores. 3, Gneiss.

Kongsberg. It was discovered in the year 1623, and, with the exception of a few intervals, it has been worked until now. The ore occurs at this mine, as will be seen by a reference to fig. 38, not so much in true lodes, as in a succession of layers of partly decomposed rock, known as 'fahlbands,' or rotten belts,' in of section. There are seven of these layers interstratified with gneissic and slaty rocks, and with which, in structure, they have much in common. They have been found productive of silver over a length of several miles, and a breadth of about a thousand feet. The ore is finely disseminated throughout the layers, but not in sufiicient quantities to pay for mining in the rocks themselves. These decomposed beds are, however, as well as the adjacent strata, traversed by true veins also con-

92 Metalliferous Minerals And Mining.

taining silver ores, and the profitable deposits of ore lie at the junction of the veins with the fahlbands ; the veins as well as the beds being too poor to work alone at a distance from the points of intersection. The total yield of silver in Norway may be estimated at 20,000 lbs. troy. Silver is also derived, from the lead ores of both Norway and Sweden.

Great Britain. — We now cross over to the British Isles, in which, although there is not a single silver mine proper, the production of this metal amounted in 1876 to 483,422 ounces,' to which if we add the production of several mines which did not specify the amount of silver obtained, the quantity will be brought up to 500,000 ounces. This amount was obtained from 80,000 tons of lead, so that the proportion of silver to the ton of ore was 6J ounces. The lead itself, as we shall see, is derived from two different geological formations : ist, the slates of the Llandeilo beds of the Cambro-Silurian strata, and, 2nd, the beds of the Carboniferous limestone. The mines worked in the former and older rocks, as in Spain, gave the largest percentage of silver. Of individual mines from this formation we find the highest 3rield of silver from Great Laxey Lead Mine in the Isle of Man, where 2,500 tons of ore gave 103,332 ounces of silver, or over 40 oimces to the ton. Foxdale Mine, in the same island, gave a nearly equal proportion. West Chiverton (see fig. 87), in Cornwall, was the next best, giving 29,925 ounces of silver to 1,594 tons of ore, or about 18 ounces to the ton. In Devonshire, the Frank Mills Mine gave 14 ounces to the ton. The average of the mines in Shropshire was 6 ounces, of Cardigan ounces, and of Montgomery ounces. The silver from the latter county came chiefly from the Van Lead Mine, near Llanidloes (see fig. 83).

Turning to the mines worked in the Carboniferous limestone, the percentage of silver to the ton of ore was 3 ounces in Northumberland and Durham, ounces in Westmoreland, 2 ounces in Yorkshire, 5 ounces in Flintshire, and 4 ounces in Denbighshire. The limestones of Derbyshire are not reported as yielding any silver. Single mines in the limestone have

Hunt, Mineral Statistics of Great Britain and Ireland,

Silver In Cornwall. 93

made large returns of silver, thus from some of the ores of Alston Moor as much as 80 ounces to the ton of ore has been obtained.

In Comwall, about Liskeard, galena has been found most productive of silver when it has been mixed with a little copper, and when this mixture took place in clay slate there was often a yield of 16 ounces of silver to the ton. Silver is also there more abundant in hard than in soft strata. The cross veins of that county do not usually contain much metallic mineral, but in some mines, at a depth of about 100 fathoms, some profitable bunches of vitreous silver enclosing crystals of galena have been found. At Wheal Ludcot crystalline grains of both vitreous and ruby silver with flakes and threads of native silver have been found. At Herodsfoot Mine, at a depth of 127 fathoms, when the galena has been found of large grains it has not usually been rich in silver; but on changing into a fine grained ore in a brecciated lode, it has become highly argentiferous. The same result has been found to occur imder similar conditions in the lode at Goginan in Cardiganshire. The metal is found associated with the copper and lead ore, known as bluestone, at Mor& Ddu, in Anglesea ; and in County Wicklow, Ireland, it has been observed disseminated in a bed of brown oxide of iron. A description of some of the chief silver lead-producing mines of the British Isles is given in the chapters treating of lead ores.

The total production of silver from 77,350 tons of lead ore raised in the British Islands in 1878 was 397,471 ounces, or about 6f ounces to the ton of ore.

Last year 27 tons 19 cwt of silver ore were raised.

" DelaB€che, GhologUai Report m Cornwall; Henwood, MetalHfmms Depottts,

Chapter Xii.

SILVER— canHnued,

Silver Ores of North-Eastem America— North-Westem America— The Comstock Lode and Ruby Hill, Nevada — The Emma -Mine, Utah — Similarity of the Deposits northwards and southwards.

North America, Eastern. — Crossing again to the North American continent we find that in its eastern half the silver produced is obtained, as in Britain, chiefly from the ores of lead. This is more or less true of the lead mines from New Brunswick southwards, and the same remark may be made of the lead region of the Upper Mississippi and Missouri, so that there is nothing in its occurrence in these regions to require special notices.

North America, Western, — It is in western America that silver mining has of late years attained a magnitude and importance unprecedented in the history of mining.

Following the gold in the driflal deposits to its source in the quartz beds and dykes amid the peaks of the Rocky Mountains, the miners were for a long time intent upon finding the auriferous metal alone. During this period they cast aside with the common metals a blue-looking substance that was more than usually abimdant The discovery of known silver ores by two gold washers, who were digging a little reservoir for their use, near the site of the town of Gold Hill, drew general attention to this mineral, so that now the number of silver mines in the Western States is legion. The quantity of silver raised last year amounted in value to the large sum of 9,000,000/., which was distributed over the various States as follows :

The Comstock Lode. 95

Arizona 1,000,000

California 4,825,000

Colorado 3,600,000

Idaho 1,000,000

Nevada 31,000,000

Other States, as Utah, Dakota, Montana, New Mexico, Oregon and Washington, and

4,650,000

/46,o75,ooo or about 9,000,000/. sterling.

It will, I think, afford my readers a fair idea of the various ways in which silver ores are found deposited in western North America if I select from the above States three lodes or groups of mines, each of which besides being the representative of a mode of deposition, is also for other reasons familiar by name to most of them. These are : the Great Comstock Lode of Nevada, the Eureka Deposits of Eastern Nevada, and the Emma Mine of Utah.

Usually, the Great Comstock lode is considered a fissure vein. It nevertheless occurs at the junction of two dissimilar formations, and it may therefore be a mineralised bed. It runs roughly north and south along the eastern slope of a range of hills that course parallel to the great Sierra Nevada range, at a distance of about fifteen miles to the east. It may be foimd on a map south of the Central Pacific Railway, between the lakes Bigler and Carson. The lode has been followed for over four miles in length, and about thirty-five mines have been opened along its course, the most successfiil of them being known as the great 'Bonanza' mines. The Sutro Tunnel, which has been in progress nearly ten years, struck the lode in the Savage Mine in 1879, and when the branches north and south (shown on fig. 40) are completed, the whole of the mines can be drained to a depth of 2,200 feet, from the outcrop of the lode on the side of Mount Davidson. The width of the lode varies firom 100 to

' Raymond, Mining Statistics west of the Rocky Mountains,' Engineering and Mining yottmal New York, May 1878 ; Sutro, The i:itUf% Tunndto the Comstock Lode,

96 Metalliferous Minerals And Mining.

t I

Structure Of The Comstock Lode. 97

o feet, and it dips eastward at an angle of 45 degrees from

0 the horizon. Its course

. aDd dip follow, as I have

£ said, generally those of

the strata by which it is S bounded, A reference C to fig. 39 will show that 3 it iies between syenite 5 below, and talcose and g metamorphic slaty rock i3 above. The latter rock J contains felspathic dykes, and it is inteistratified by

h 0 felspathic beds. The sy-

enite and possibly the im- I t mediately overlying slaty

a rocks may correspond to

I E similar silver - bearing

0 strata of Llandeilo age in i I our own country. The

5 overlying strata with their

, I volcanic dykes and lavas

J S being apparently of ter-

" J tiary age.

£ Generally Speaking the

1 non -metallic contents of i the lode consist chiefly of quartz, fluorspar, chlorine, i and sulphur, throughout which are disseminated X gold and silver in the pro- S portion of about one-third 3 gold and two -thirds sil- S ver. But little antimony is I found with the silver.

The lode is not uni- - - - - , fomJy rich throughout, as

98 Metalliferous Minerals And Mining.

will be inferred from the segregation of the ore into great ore bodies, as shown in the longitudinal section dg. 40. Starting on the north of the section, and passing by the scattered ores of the Utah and Alten mines, we find four chief ore bodies between the Utah and the Chollar Potosi, a distance of over 12,000 feet The first of these ore bodies in the Sierra Nevada ground contains gold and silver to the value of firom i/. to 2/. per ton, besides which it has low grade ores of the value of fi'om 12s. to 30i'. per ton, which at present hardly pay for working. The ground has been explored to a depth of 600 feet below this ore deposit, but has proved barren. Between this and the next ore body, in the Ophir and Mexican claims, is a stretch of 1,600 feet of comparatively barren ground. This second ore body is partly exhausted of its rich ores, of which it has yielded immense quantities. A large quantity of low grade ores remain, which cannot now be profitably worked. At a depth of about 700 feet, the lode was pinched and partly fljled by porphyries, the quartz disappearing ; but an ore body lies at a greater depth in the Consolidated Virginia Mine. The next ore body starts in Gould and Curr/s ground ; it is over 2,000 feet in length and 1,000 feet in depth. This, the Potosi Chimney, has been one of the richest deposits, and has yielded about 3,000,000/. Its rich ores were extracted at the' rate of 650 tons a day, at a value ranging from 17/. to 25/. per ton of ore. It ran out in depth into a quartzose rock, six feet wide, mixed with clayey matter. A similar deposit to the last occurs in the Chollar Potosi mine. Latterly a lower ore deposit has been struck in the Hall and Norcross Mine, at a depth of 1,100 feet. It has been laid bare for 260 feet, and it is from six feet to thirty feet wide. Its ores differ from those on the higher levels in containing more galena, copper, iron, and blende. They average 6/. per ton, although selected parcels have made 13/. per ton. The richer portions are irregularly distributed through the thirty feet of quartz lode, portions of the latter from fifteen to twenty feet square only yielding 5/. to the ton. The shaft of the next mine, the Savage, has reached a depth of 2,300 feet, and it is this mine which the Sutro Tunnel has just

Mines On. The Comstock Lode. 99

entered. At a depth of 1,000 feet it entered the ore body just described.

Below the ChoUar Potosi deposit, at a depth of 800 to 1,200 feet, the lode was partly filled with porphyries, with occasional thin quartz seams, containing only traces of ore. It had a large quantity of ore, in value from 3/. to 5/. per ton.

Another great ore body extends from the Exchequer to the Crown Point. From this also most of the rich ores have been extracted, leaving a large quantity of the value of from 2/. to 3/. per toa In the various mines on this part of the lode, at depths ranging from 1,100 to 1,500 feet, the lode expands to about 90 feet in width, made up largely of porphyry and compact quartz, containing small quantities of the sulphides of lead and zinc, with only traces of silver. These metallic ores were found in quartz seams on each side of the lode, the middle of which for a great thickness was filled up with barren porphyry. As a rule the more compact the quartz the less productive, and the more sugary it becomes the more largely it is charged with metallic ores. It will be observed that there is a deeper ore body in the Belcher and Crown Point daims. Thus far these deeper ore bodies have not been so rich or so large in metals as the higher ones ; the matrix also contains more carbonate and sulphate of lime. It becomes a serious question whether the productive character of the lode has ceased in depth, or whether, as in the case of the Chanaracillo Mine, fig. 44, the lode is only temporarily pinched by passing through and calcareous ash. It is much feared that the former is the case. Explorations will, however, be aided by the deep tunnel now made. The mines will be drained, and the low grade ores, of which large quantities remain, may be mined more cheaply.

The estimated value of the yield of the Comstock lode for some years has been 3,500,000/., and its total yield since its discovery in the year 1859, 70,000,000/. sterling.

The country adjacent to the Comstock lode is reticulated with lodes and veins. Some of the chief of these are shown on the section, fig. 39. In the Flowery district the Lady Bryan

Mine is worked at surface, near 300 ffeet wide. Native silver

H 2

100 Metalliferous Minerals And Mining.

has been found in it, and fine sulphides yielding the value of 9/. to the ton of ore. The Monte Cristo lode has also yielded in places large returns.

The town of Eureka,* which has grown up within the mines of the district, is situated in the eastern part of the State of Nevada, 91 miles south of Palisade station, on the Central Pacific Railway, with which it is connected by a narrow gauge railway — the district surrounding, which is traversed by the mineralised strata now to be described, forms a range of hills that lie between the ridge containing the Comstock lode and

Fig. 41.— Structure of Ruby Hill, Eastern Nevada, showing Mineralised

Limestone Beds.

1" poo ft.

z, Qtiaitzites. a. Mineralised limestone beds. 3, Shales. 4, Dolomitic limestones.

5, Ore deposits

the Wahsatch range of mountains, in which the Emma Mine with others is situated. Indeed, the country intervening between the Comstock and the Emma is traversed from north to south oy several similar chains of hills, some of which are so highly mineralised as to have given to Nevada the name of the Silver State.

Silver Hill, Prospect Mountain, and Ruby Hill are parts of such a range of hills which lies immediately to the west of the town of Eureka. They contain at present about sixty distinct

Engineering and Mining Journal of Neva Ybrk, December 1877, January 1878.

Structure Of Ruby Hill. 10 1

silver mines. The metal was first discovered here m the year 1864 by a party of miners, on their way to White Pine. Some laggards' of the party, seeking an easier road, saw some rich mineral 'float' in what is now known as New York Canon. They quickly made locations, but little was done until the year 1869, when a small furnace was set up. Later, the Eureka Consolidated Mining Company was formed out of several small mining setts, and more recently the Richmond Consolidated out of a number of others.

The diagram, fig. 41, illustrates the structure of Ruby Hill, on which these great mines are situated.' i consists of granites, quaitzose slates, and metamorphic rocks of great thickness. 2 is a belt of limestone, 300 feet thick. Judging from the fossils found in it, it is of Cambro-Silurian age, and it contains segregations of ore. It is surmounted by calcareous shales, 3, and these by higher limestones, possibly of Carboniferous age, and which form a belt of great thickness.

The mineralised belt of limestone, 3, is, where unaltered, dolomitic in character, containing firom 34 to 46 per cent of carbonate of magnesia. It also varies firom i to 2 per cent, of oxide of iron. Where bedding is apparent, as in the Phoenix Mine, it is confonnable to the rest of the stratification, but for the most part the bedding is not discernible, owing to the phenomena now to be described.

The limestone, 2, has been 'greatly crushed and shattered, and within the mine workings it may be seen, now broken up 'into great masses, then roughly crumbled into small fragments, and again, especially where it is of a sandy nature, ground into fine powder. The shattered fiagments have for the most part been recemented by calcareous matter, and form a hardened nuiss. The sandy portions of the limestone are often dangerous, because of their tendency to run in. In the midst of these reconstructed limestone beds huge caverns (pre chambers) are found, the sides and roofs of which are lined with stalactite and crystals of arragonite, while the floors are covered to a greater or less depth with metallic ores. These caverns are due to chemical action, aided by mechanical causes. In other words.

102 Metalliferous Minerals And Mining.

the carbonate of lime has been dissolved out of the mass by the infiltration of water, the passage of which has been rendered easy by the cracks and gaps left in the shattered limestone.

The first ore cavity found was on the site of the Champion Mine, and it lay below a spot where ore was found on the surface. Below this cavity, at a depth of about 300 feet from the surface, a larger cavern has only recently been discovered.

Besides these irregular cavities, the limestone is traversed by two main systems of fissures, one running parallel to the strike, and another at right angles across the beds. These last are nearly vertical, and at the points where they strike the underlying quartzite, which they do not enter, ore deposits are usually found. The ore deposits have a general tendency towards the dip of the beds. They start high up in the limestone, as shown in fig. 41, and expand downwards towards the rock below. Near the points of junction the richest ores occur, the lower grade ranging around the sides of the deposits. In the Eureka Mine one of these deposits has been followed 200 feet along the strike, and 160 feet down the dip of the quartzite rock, and another body has been worked for 300 feet along the face of the bed. The face of this quartzose rock is somewhat undulatory, so that the ore is found filling the depressions in it, and occasionally passing over the upward curve from one hollow to the next

The ores consist chiefly of carbonate of lead largely mixed with ferruginous matter. The best quality is that known among the miners as black carbonate. This contains from 60 to 70 per cent of lead, with gold and silver ranging in value from 20/. to 40/. to the ton of 2,000 lbs. The ordinary ores contain from 16 to 20 per cent, of lead, with gold and silver valued at from 8/. to 15/. per ton. Besides these ores, there is an abundance of still lower grade ores found especially in depth, which with the present cost of mining and transport are neglected.

In the third level of the K K mine, a huge mass of quartz was found in one of the ore chambers. It was 90 feet long, 45 feet wide, and 25 feet thick. It was of a sugary texture, and was probably formed in situ by the filtration of water

The Wahsatch Mountains. Io3

charged with silica. It did not hold much lead, but it was rich in gold and silver, valued at from 5/. to 35/. per ton.

The general phenomena of this Ruby Hill limestone and its contained minerals, seem to indicate that the latter have been accumulated by the percolation of water charged with the various minerals from the overlying or adjacent older strata. The farther downward progress of this has been stopped by the unbroken quartzite and the ore largely arrested there. The crushed character of this mass of limestone, 2, seems to die out downward ; the overlying solid limestone beds and strata approaching the quartzite in depth. It is therefore a V-shaped portion of the lower part of the great limestone zone, crushed and broken between the beds above and below, and thus made a fitting depository for the ores once disseminated throughout the entire mass, which have been added to the richer ores that, possibly prior to the deposition of the limestones, had accumulated in the hollows of the quartzite rock.

The Emma Mine, apart from the unenviable notoriety it has gained by litigation, will serve my purpose in illustrating a deposit of silver ore under different geological conditions to those of the Comstock and Eureka or Ruby Hill deposits, and it may be taken as the representative of the group of mines with which it is associated — the Flagstaff, Silver Star, Exchequer, and others.

The Emma Mine is situated, along with the other mines just named, in the Wahsatch range of mountains, the higher peaks of which rise 1 2,000 feet above the sea level. The range courses north and south, about twenty miles east of the Great Salt Lake, and it forms a parallel ridge of similar structure to the main chain of the Sierra Nevada. Numerous streams come leaping and tumbling down the deep canons that furrow the side of the range, and flow into the Salt Lake. It is up the most southerly of these, the Little Cottonwood Creek, about twenty miles SE. of the lake that the Emma and other mines are worked.

A. C. Peale, Untied States Geological Survey, 1873 ; W. Raymond, Report on the Emma Mine, 1872,

r04 METALLIFEROUS MINERALS AND MINING.

Ascending from Salt Lake City to the higher parts of the range up this creek, we have a grand natural section of the geological structure of the country. Near the mouth of the creek, on the west, great granite peaks covered with snow rise on either side. The granite is in massive beds that dip at an angle of from 50 to 70 degrees to the east. The granite is of a light grey colour, and is composed of white felspar, quartz, and black mica. It is of this granite that the Mormon Temple of Utah

Fig. 43.— Transverab Section or the Great Orb Chamber at the Emma Mikb.

x" 159 ft.

is built. This continues for five or six miles up an ascent of 500 feet to the mile, then the granites are seen overlaid by quartzites of a reddish colour. These are succeeded by a series of slates, upon which rest thick beds of white limestone, supposed to be Cambro-Silurian. The passage of these into the Carboniferous group is rapid, massive dolomitic limestones of Carboniferous age being seen resting upon the greatly older

The Emma Mine. 10$

limestone beds. It is in these Carboniferous limestones that the ore deposits are here foimd, and the Emma and associated mines worked. Fig. 42 represents a transverse section through the great ore chamber of the mine, from which it will be seen that the ore masses correspond roughly to the line of bedding. Underneath and above the ore horizon there are beds of white dolomitic limestones. Between these, there is a thickness of about 250 feet, which seems to mark the limits of the ore horizon. In this zone are great irregular masses of brecciated limestone that contain spots and lumps of galena, and patches of soft earthy ore. Following roughly the lines of bedding, are great segregations of metallic ores, like those taken out of the chamber shown in the figiure. These metallic ore deposits seem to be confined to the upper and lower sides of this mineralised zone, the levels that have been driven across it not having apparently struck any ore chambers in the middle part of it The repetition of these ore chambers will probably be found along the course of the beds at these horizons, and down the dip.

The character of the orey matter from these deposits will be gathered from the following analysis by Mr. James P. Merry, of Swansea, of an average sample of 82 tons of first-class ore :

Per cent.

Silica 40-90

Lead 34'i4

Sulphur 2'27

Antimony 2*27

Copper 0*83

Zinc 2*92

Manganese 0*15

Iron 3*54

Silver 0*48

Alumina 0*35

Magnesia 0*25

Lime 0*72

Carbonic acid 1*50

Oxygen and water by difference. . 9*58

I06 Metalliferous Minerals And Mining.

The quantity ot silver actually obtained from this consignment of 82 tons, was 156 ounces to the ton of 2,240 lbs. The second class ores yield about 25 ounces of silver to the ton. The absence of lime from this orey matter in the midst of limestone is remarkable.

The section, fig. 42, shows the size of the ore chamber under Woodman's or Discovery shaft. Further to the southeast, under the Emma shaft, it is not of such large dimensions. It has only been explored at this mine for a length of about 300 feet But the reciurence of similar segregations has been proved in neighbouring mines, and, judging firom the latest reports, in the Emma Mine itself, which we are told is being worked to profit by the original American owners, while the English shareholders are engaged in litigation.

Still farther to the north-east mining for silver lead is progressing in the upper reaches of the rivers that form the Missouri, but nothing of practical or scientific interest can be added to the description just given of mines in the same strata in Nevada and Utah.

Occurring in or near the older rocks, as in the Comstock lode and in the quartz portions of the Ruby Hill deposits, silver is found as ores which may be separated by washing and mechanical action, and are known as free milhng ores. As found m the limestones at Ruby Hill, and those of the Wahsatch mountains, the sUver is chemically blended with lead and other metals, and the ore therefore requires to be smelted.

If the reader will now take a map of western North America, and follow the line of these three mineral deposits south-easterly into New Mexico, Arizona, and Mexico, he will have in the three descriptions I have just given the explanation of the chief modes of the occurrence of silver ores in those regions.

10/

Chapter Xiii.

SILVER— continued.

Silver in Arizona — Mexico — The South American Continent — Peru — Bolivia — Chili — Western side of South America generally — Concluding Observations and Deductions.

In Arizona the lodes follow the stratification and extend for miles. Those of the Globe district correspond to the class of which the Comstock lode, described in the preceding chapter, belongs. They are composed of quartz, crystallised felspar, yellow spar, and limestone, the metallic ores, chloride of silver, and native silver, with sulphides and silver glance, besides which they carry subsidiarily antimony, arsenic, copper, and galena. This State has only been lately opened up as a mmeral country, although its rich mineral character was previously known.

Mexico was formerly famous for its silver mines, and probably under Anglo-Saxon management it may become famous in the future. We find two distinct classes of deposits in this region : first, those of the old rich mines of Pachuca real del Monte and Moran, which occur, like the Comstock, between porphyritic and slaty rocks ; and secondly, those of Real de Calorce and the mines near Zimapan, that occur in limestone, like those of the Wahsatch range, the lodes running up into even higher limestones. In both Arizona and Mexico there occur large quantities of native silver, which some have thought have been naturally smelted from the ores by volcanic heat* We now pass rapidly southwards to the South American continent, and passing bv the mines of Central America, Venezuela,

H. S. Jacobus Report, Mining Joumal, 1877,

I08 Metalliferous Minerals And Mining.

and New Granada, which are of increasing importance, we will at once notice the silver mines of Peru and the countries lying to the south.

Peru. — The name of Peru is closely associated with the idea of silver wealth. The great chain of the Andes, as it courses down western South America, maintains the same geological structure as that prevailing in the Rocky Mountains of western North America, and the silver lodes occur under similar conditions in both continents.

The principal silver mines of Peru are those grouped about Yauricocha or Pasco, about half-way down Peru. These were accidentally discovered in the year 1630.

The neighbourhood contains a variety of silver deposits,

Fig. 43.— Arcbntifsrous Strata, Santa Rosa Minb, Pbsu. A, Beds charged silver ores, b. Limestone, c, Silt or porphyry, d. Shales.

the relationship sustained by each to the other being only imperfectly understood scientifically. There are two principal silver lodes or horizons of strata, named respectively Veta de Colquirica and Veta de Pariarica. The first of these has a direct north and south course, known for two miles with a breadth or thickness of 400 feet The second runs from WNW. to ESE., and crosses the first under the market-place of the town of Pasco.* Besides these there are in the district, as at the Santa Rosa Mine, argentiferous beds like those of Norway, fig. 38, only richer.

Mr. Rutter, of Camborne,* describes a series of such beds, of which fig. 43 may be taken as an illustration.

13,673 feet above the sea. Mining J&malt September 8, 1877.

SILVER MINES OF PERU. lOg

' A represents a flat mass of mineralised rock composed of gossan, iron quartz, and pyrites. It lies in a basin -shaped hollow in limestone and sandstone rocks, which is about threequarters of a mile in diameter. Where the deposit abuts against or graduates into the limestone, small veins containing lead ore are observable ; but they do not seem to have any relation to the silver ores of the deposit. At 148 yards from the surface a shaft that was sunk passed through the deposit, and entered a grey-spotted porphyritic rock, which lay upon a bed of silt, containing fragments of limestone. It is a pity this shaft was not sunk deeper.

The details of the geological structure of the country are not clearly made out, and it may be that one of the two great lodes described above may be a mineralised series of beds — probably the north and south one. The deposits have been generally supposed to have become poorer in depth, which, if they are beds 'or segregations of metallic ore, is reasonable to expect ; but if thpy are really lodes of great width, there may be only a local deterioration, as in the case of the Chanaracillo lode, to be described: bul the deep tunnel about to be driven by Mr. Meiggs,* who has done much. for the development of Peru, will solve the problem.

At Hucantajaya, nine English miles from Aquique, there is a radiation of nearly vertical lodes from a common centre, and these are crossed by smaller veins, containing silver. The hill Aquique, from which these lodes radiate, is composed in its upper portion, and to a depth of 70 yards, of a conglomerate of medium-sized stones, set in calcareous matter. In this conglomerate the prevailing ore is a chloride of silver. Lower down the ores change to sulphides.

At Santa Rosa and Huantaca, near Aquique, silver is associated with nickel and copper ores, which are more abundant than at Huantajaya, where Uie amount of copper is reduced to about 4 per cent of the metallic ores.

Heretofore the mines of this district have been very carelessly worked, so much so that only the most prolific mines

' Since the above was written Mr. Meiggs has died.

no METALLIFEROUS MINERALS AND MINING.

could pay for working. The total yearly yield of the country may be taken at 300,000 lbs.

Bolivia. — Following the Andes southward into Bolivia, we reach, about lat. 19° S. and long. 65° W., the famous silver mines of PotosL These were discovered in the year 1545. They are worked in the isolated mountain of Potocchi, which rises 16,000 feet above the sea. It is traversed by thirty- two principal lodes, as well as by a number of smaller veins, which form a network in the older rocks of which the mountain is composed. The amount of silver yielded by these mines since their discovery may be estimated at 300,000,000/., or about one million sterling a year, besides the ore that has been wasted by the reckless way of working. The mines have been worked to a depth of about 1,000 yards. The proportion of silver ore is reckoned at i ounce fine silver to i lb. of ore. Peru and Bolivia, taken together, contain about four hundred abandoned mines, many of which with proper appliances and skilful management might doubtless be profitably worked.

Chili. — Still following the Andes southward, we come to the well-ordered Republic of Chili, whose mines are better worked, and are very numerous and productive. It may be observed here, generally, of Chili, that its mines have been grouped into four districts, which are distinguished firom each otlier by the presence of various metals associated with silver ores, and the variation in the ores of that metal.

Starting on the north, there are first the mines of the mountains north of the valley Huasco, which are ricJiest in silver, but which also contain gold and copper. Secondly, there is the district between Huasco and Coquimbo, in which are numerous veins of pyritous copper, and between Arqueros and Aquaamaza, chloride of silver and native silver. Thirdly, there is the district between the valleys of Coquimbo and Aconcagua, where in granitic rocks gold-bearing veins are common ; and, fourthly, there is the district south of Aconcagua, where we find granites filled with auriferous lodes, and mines of silver

See also Whitney, Metallic Wealth; and Henwood, Metalliferous Deposits,

Chanaracillo Mine, Chill

Nmture of Lode*

Thin veins of sulphuret of silver

Flakes of native silver and chloride of silver in joints of limestone near the vein

Seven to thirty lbs. of silver to the ton of ore

Sixty lbs. of silver to the ton

From the depression in the greenstone ore to the value of SoolbSk of silver to the ton was obtained

No silver in the vein as it passes the porphyritic rock

Lar deposits of opench in silver, 40 lbs. of silver to the toik of one. Lode melts into limestone

No silver ore

A little silver ore m the thin limestone No silver ore

Strata

ly Beds of brown, blue, and buffcellular limestone, containing grey silver ore and chlorides of silver fillmg its joints, native silver in crevices near the lode

Fine blue limestone, with arsenical pyiitef

Flinty limestone

Arenaceous ditto Greenish-grey ditto

Dark blue compact limestone

Porphyritic and hornhlendic rock, traversed by veins of quartz

Fin€-grained dark and grey limestone Dark yields silvergrey, barren

Greenstone rock.with veins of calcareous spar, thin bed of argillaceous limestone m centre

Gradual passage into limestone below

Beds of blue, grey, and greenish-grey limestones, with irrelar deposits and thiu veins of calcareous spar, and lines and spots of chlorite and asbestM

Sulphuret of silver I J lbs. to the ton of ore

Fic. 44. — Sbctioh of Strata and Dbscription of thk principal Lodb at Chanaracillo, near Copiapo, in Chill

112 Metalliferous Minerals And Mining.

and argentiferous copper worked in the stratified rocks overlying the granites along the summits of the Andes.

We may take the neighbourhood of Copiapo in the first of these groups as a representative one of Chili, and a description of the old Chanaracillo Mine will serve to illustrate the usual mode of the occurrence of silver ores in true fissure lodes in older limestone.

This lode was discovered in the year 1831, and up to 1853 the mine had yielded 2,035,424 lbs. of silver.

Fig. 44 represents to scale the size of the lode, and the variations in the strata through which it passes ; annexed to it there is also a description of the strata, with the particular features and composition of the lode at the various depths given. The limestone is probably of the same age as the silver-bearing limestones of Nevada, and both probably correspond to the lower part of the limestones the gold deposits of Congo Soco, fig. 21, on the eastern side of the continent The limestone beds dip to the south-west, and the lode dips in a contrary direction. The earthy matter of the lode partakes largely of the nature of the strata it passes through, being partly filled with disintegrated fragments of the adjoining rock. It is destitute of silver as it passes through the greenstone, but is most productive in the limestones at their junction with the upper surface of that rock. The limestones themselves are charged with silver in grains and dust throughout their mass ; the oidinary joints are charged with silver ores, and in the joints near the lode there is much native silver. At these points, where the joints open upon the lode, the walls of the latter are not well defined, the lode and the limestones gradually changing into each other. In 1856, the silver derived from each ton of ore was 466 ounces troy, the total producuon of the mines that year being 115,656 ounces. Within this quantity, the vitreous red and rarer ores yielded from 90 to 100 ounces per ton.

All down the western side of the South American continent, chloride of silver is the common ore, which is to be expected in a country so abounding in deposits of saline matter. As a rule

Concluding Inferences. 1 1 3

93 per cent, of chloride of silver ore makes 70 per cent of metallic silver. Where much antimony is present, as in ruby silver, the sepsiration of metallic silver from the ore is somewhat difficult

Such are the principal silver deposits of the world. It is probable that in a few years Australasia will take her place as a silver-producing continent Already, in 1876, New South Wales produced 69,179 ounces of silver, of the value of 15,456/., and Victoria in the same year yielded 26,356 ounces, nearly the whole of which was separated from the gold melted at the Mint In 1879 silver derived in th same way amounted to 23,72902. 15 dwt

From the foregoing description it will be seen that silver occurs at two distinct and separate geological horizons. First, at the junction of the Cambrian with the Cambro-Silurian groups of rocks, in slates and calcareous strata ; and, secondly, in the Carboniferous limestones. Of the first horizon it may be said that, in the lower part of it, probably down in the Cambrian strata where limestones are absent, silver ores are mixed with metallic gold, and both are separable by mechanical means from their admixtures. In the limestones and upper portions of the group in the Llandeilo. slates, they are chemically blended with other metals and need smelting. The same is true in a greater degree of the higher group — the Carboniferous limestone. The favourite metallic associate and repository of silver is lead, and it is contained in a larger proportion in this metal when both metals are foimd in the slates and shales of the older rocks than in the newer limestone : the proportion of silver in lead ores apparently decreasing with the deposition of the newer limestones. The presence of silver in lodes or strata is not usual in beds newer than the Carboniferous limestone, although in Peru Coal-measures rest immediately upon limestones charged with silver; and in the Banat, in Austro-Hungary, a much newer limestone of the Cretaceous period rests immediately upon metallic deposits formed on the surfaces of a vastly older rock ; and in the Comstock lode very recent strata lie not fax above the lode 01 bed.

Chapter Xiv.

Copper,

General Remarks — Native Copper — The Ores of Copper.

Although not so costly, copper can hardly be said to be less valuable than either of the two noble metals already described. Its numerous applications to the uses and purposes of life are already familiar to my readers, and I need not, therefore, enumerate them, but proceed at once to describe the principal forms and ways in which it occurs in nature.

Copper is found native, as in the mines of Lake Superior, and also in various combinations with acids, as well as with oxygen, sulphur, and other substances. The ores range about 4 in hardness, and from 3*5 to 8-5 in specific gravity ; the latter being that of native copper, and the former that of the ordinary carbonates.

Native Copper. — This is found more or less in most mines associated with the ores. It occurs in lumps of all sizes up to great masses of many tons weight A mass taken out of the Cliff Mine, described further on, measured 40 feet long, 6 feet deep, and 6 inches thick ; its weight was estimated at 200 tons. Silver is, as we have seen, usually intimately mixed with native copper, but is also in distinct specks, flakes, and crystals in the metal, as if, in the process of cooling, each metal had gathered itself together and had solidified separately.

The principal ores of copper are the following :

Copper Glance {Redruthite). — Composed of 79*8 of copper and 20'2 of sulphur, with sometimes i to 2 per cent, of iron replacing a portion of either mineral Its hardness is from to 3, and its gravity 5*5 to 5-8.

Varieties Of Copper Ore. Iis

This ore comprises the following varieties :

Blue Coppery also named Covelline and Kupferindig. — Composition : 667 copper and 33*3 sulphur.

Digenite. — Composition : 70*20 copper, 29*56 silver, and 0*24 silver.

Copper Pyritesy or Sulphide of Copper, — This is the most abundant ore of copper. Composition : copper 34*6, sulphur 34*9, and iron 30*5. It is of a brass yellow coloiu:, and resembles both specks of gold and iron pyrites. It may be distinguished from the former metal by crumbling when an attempt is made to cut it, and from the latter by its yielding to the point of a knife and its not striking fire, as well as by its deeper yellow colour streaked by a greenish black. Under the blowpipe it fuses into a steel-grey globule, which is magnetic If the ore is of a fine yellow colour and yields readily under the hammer, it is good ore ; but if it is hard and of a pale colour, it is poor, through containing more iron pyrites. Its usual hardness is 3*5 to 4, and its gravity 4*1 to 4*3. Its varieties are :

Cuban. — Composition : 22*96 copper, 42*51 iron, and 34*78 sulphur.

Variegated or Purple Copper or Variegated Copper Pyrites. Bomite, — Composed of 55*6 copper, i6'4iron, and 28 sulphur. Sometimes called horseflesh ore.' Colour, from red to brown ; tarnish from steel blue to pale grey, with a greyish black streak. Occurs in crystals near Redruth in Cornwall, and also in Connecticut.

Grey Copper Ore {Tetrahedrite), — Composition : copper 38*6, sulphur 26*3, antimony 16*5, and arsenic 7*2. There are also slight varying quantities of iron, silver, and zinc In a sample from Spain there was 10 per cent of platinum, and in another from Tuscany 2*7 per cent of mercury. Its colour varies from steel grey to iron black, sometimes showing a brownish hue — the less arsenic in the composition the darker the colour. Containing 17 to 31 of silver, the ore constitutes the silver fahlore of Freiberg. Its varieties are :

Antimonial Copper. — Containing 47 of antimony.

Boumanite, — 20*3 sulphur, antimony 26-3, lead 40*8, and

Il6 METALLIFEROUS MINERALS AND MINING.

copper 127. Of a brilliant metallic lustre, in colour from steel grey to iron black. Hardness, 2-5 to 3 ; gravity, 57 to 5'9.

Domeykite, — 71 "63 copper, 28*37 arsenic. A portion of each being often replaced by iron and sulphur. Tin or silver white with an iridescent tarnish.

SeUnide of Copper, — 64 of copper, with selenium. A silver white ore. Gives off a horse-radish-like odour under the blowpipe.

Tennantite, — A mixture of copper, iron, sulphur, and arsenic. Occurs in brilliant crystals in some of the Cornish mines near Redruth.

Red Copper Ore (Cuprite). — An oxide of copper. Composition : 88 '9 copper, and ii'i oxygen. Hardness, 3-5 to 4 ; gravity, 57 to 6. Colour, cochineal to red, with a brownish red streak, and a bluish grey tarnish. Its varieties are :

BUuk Copper Ore ( Tenorite). — 60 to 70 per cent of copper, with oxygen. Occurs in botryoidal concretions, dull black masses, and black powder associated with other copper ores ; also in the lavas of Vesuvius. Originates in the decomposition of sulphides and other ores.

ChaUotrichite, — Composition like cuprite. Occurs in fme hairlike crystals of a crimson red colour.

Tile Ore.— An oxide of copper mixed with much peroxide of iron and other earthy substances. Reddish brown in colour.

Sulphate of Copper {Blue Vitriol). — Composition : oxide of copper 31*8, sulphuric acid 32*1, water 36'i. Coloiu*, skyblue. Consists of sulphide of copper in solution. Contained in the water flowing from many copper mines, where the copper is usually, as at Parys Mountain and Rio Tinto Mines, derived from the solution by precipitation. Variety Brockantitey an insoluble sulphate of copper, containing 17-5 of sulphuric acid. Occurs in emerald green crystals at Ekaterinberg, in the Ural Mountains.

Green Carbonate of Covvie. {Malachite). — Composition: 71*8 protoxide of copper, 20*0 carbonic acid, and 8-2 water. Hardness, 3-5 to 4 ; gravity, 3*6 to 4. Colour, light green with paler green streak.

Copper Ores Continued. Ii7

Blue Carbonate of Copper {Azurite). — Composition: 69'i protoxide of copper, 257 carbonic acid, and water 5*2. Hardness, 3*5 to 4*2 ; gravity, 37 to 3 '8. Colour, azure blue with small blue streak ; transparent to nearly opaque, and of a vitreous lustre.

The varieties of the two foregoing 6res are :

AurichakiU, — Composed of 29 copper protoxide, 44 of zinc oxide, 16 '2 carbonic acid, and 9*9 of water.

Chalcophyllite, — Composition : 49 6 copper protoxide, 18 arsenic acid, and 32 water.

Chrysocolla or Copper green (silicious malachite). — A silica of copper, composed of 44*94 copper protoxide, 34*83 silica, and 20*23 water. Colour, azure blue to emerald green.

Emerald Copper. — 50 protoxide of copper, 38*7 silica, and 1 1 water. Colour, usually emerald green, but occasionally dark green.

Erinite. — 59*9 protoxide of copper, 347 arsenic, and 5*4 water. Colour, grass green.

Euchroite, — 47 'i protoxide of copper, 34*2 arsenic acid, and 87 water.

Klinoclase (Aphanese Abichite), — 62 '6 protoxide of copper, 30*3 arsenic acid, and 7"i water. Colour, bluish green to verdigris green.

Olioenite, — 56-5 protoxide of copper, 39*5 arsenic acid, and 4 water, with a proportion of from i to 6 of phosphoric acid. Olive green to black green, with brown and olive green streaks.

Phosphorchalcite {Lunnite), — 70*8 protoxide of copper, 2 1 phosphoric acid, and 8 water.

There are numerous variations of the last family, as AtacamiUy Ehlite Libethenitey Tagilitey Volborthite and Urantte, all uniting phosphoric acid, and the minerals included in the carbonates of copper in slightly different proportions.

Cupriferous Cobalt Ores. — There are also some varieties of copper ores which shade off into cobalt on the one side, and nickel on the other, but they do not require special description here.

Chapter Xv.

COPPER-OHiimted.

The Ores of Copper in Russia — Ural MonntainsWestem Side of the Ural Mountains — Caucasus— South Africa — The Cape — Algiers— Spain — Italy— Austria— Germany: Prussia — Norway — Sweden — France.

Copper is mined in China, Japan, and India, but as yet we have but few particulars concerning the mode of its occurrence, so that in again commencing our westward joiuney we must content ourselves by starting from the eastern side of the Ural Mountains.

Russia, Ural Mountains, — On the eastern side of this chain copper is worked in the Cambro-Silurian rocks, near Nijny Taglish. The strata consist of clayey shales, interstratified with calcareous beds, like our Llandeilo limestone. The ores are chiefly malachite, and the red oxides of copper, which occur in bunches and nests in the strata. The malachite occurs in large solid masses, one of which, a cube of feet diameter, is in the School of Mines at St Petersburg. It was found at a depth of 280 feet, and weighed 580 tons.

The deposits near Bogolowsk are also found in similar limestones, which are interstratified with beds of trap. Between the limestones and the traps are clay deposits, in which the copper ores lie in bunches and nests, together with beautiful crystals of native copper.

Copper mines are also worked on the western side of the Urals, in permeated cupriferous beds, and irregularly stratified deposits in the Permian rocks. Southward, too, in the Caucasus deposits of copper ore are worked that in 1876 yielded 536 tons of copper. We have no particulars of the nature of these

South Africa. Algiers. Ii 9

deposits, but probably they lie in the older locks, like those on the east side of the Urals. The total production of copper in Russia last year may be estimated at 6,500 tons.

South Africa, The Cape. — For the present we must be content to pass the land of Midian above the head of the Gulf of Akaba — from whence Captain Burton has just returned with tons of mineral specimens, copper ore included — and take a run down to the far south-west of Africa, where copper mines are extensively and successfully worked in Namaqualand. The mines, of which there are two, are worked in deposits that are found in the range of mountains that, some 80 to 100 miles inland, run down the western side of South Africa. Here the basement rock is gneiss, overlaid with schists. Interbedded and intrusive felspathic rocks run in a general east and west direction at this point, and the cupriferous ores are distributed throughout portions of the felspar in grains and lumps, from a minute size up to several hundred pounds in weight The felspathic rock is hence called the copper bearer. One of the principal mines is the Okatiep, near Springbok, 90 miles from the coast, and the other is Spectakel, in the Copperbeig, 20 miles nearer Port NoUoth, with which port both mines are connected by a railway. The ore is chiefly purple and peacock ore, and some of the stopes are worth as much as four tons per cubic fathom. The average quality of the ore during the last three years has been 30 per cent The prices obtained during the same period will illustrate the recent depreciation in the value of copper ore. In 1875 the price per unit was i6j., in 1876 141. 7., and in 1877 12. 4. The production has been equal to 12,000 tons a year, on which the profit last year was

Algiers. — Retracing our steps northward, we find that copper ore is obtained in Algiers, near the foot of the Mouzia Pass, and the deposit is interesting as occurring near the summit of the chalk, which is here traversed by veins containing grey copper ore mixed with spathic iron. The total production of copper in Algiers in 1875 was rather over 3,000 tons. In

' Mining Journal voL xlviii. p. 605.

I20 Metalliferous Minerals And Mining.

1878 we importecL copper ore fiom Algiers to the extent of 3,674 tons.

Spain. — Crossing the Mediterranean into Spain we find numerous copper deposits, or, more strictly speaking, deposits of pyrites containing a percentage of copper. These occur as beds, and as fissures filled with metalliferous ores. Fig. 45, adapted firom one given by Mr. S. R. Pattison, F.G.S.,* illustrates one of the former as it occurs in greenstone at the Buitron Mine, in the province of Huelva.

Fig. 45.— Sbctiom of Pyrites Deposit, Huelva, Spain. a a, Fahlband. 3, Decomposed clay slate, c and d. Greenstone.

The deposit, a a, here is. a nearly vertical bed about sixty feet wide. It is made up of fine bedded sand, permeated with an average of 3 per cent of copper, 48 per cent of sulphur, with about two shillings' worth of gold and silver to the ton of ore. For some distance from the surface the orey mass, a a,

S. R. Pattison, *The Pyrites Deposits of Huelva,' Geological Magazittfj No. 2, 1872.

Italy. Austria. Germany. 121

is decomposed. The whole deposit lies between greenstone, ify below, and clay slates, //, above.

The deposits of the Rio Tinto Mines, near Seville, are of a similar nature, the proportion last year being 2,735 *ons of metallic copper to 211,000 tons of pyrites. The metallic copper was extracted from 520,391 t6ns of ore. The water flowing from the mines yields 3J tons of copper weekly by precipitation. The principal deposit is worked as a great open quarry, and it is estimated that there is still on the property some million tons of ore.* The total yearly production of copper in the shape of regulus and concentrated ores in Spain and Portugal combined, may be taken at 26,000 tons.

Italy. — Bending eastward a little, Italy contains contact deposits of copper at Monte Catini, and which so far have retained their value in depth.

Austria, — North-east, in the Banat, whose geological structure has already been described, see figs. 17 and 36, copper ores are contained in the contact deposits that lie between the Cambro-Silurian rocks and the Jurassic limestones.* The ores are poor, seldom exceeding 3 per cent. They consbt chiefly of copper pyrites, associated with arsenic, which are scattered throughout the gangue of the deposits, but are concentrated chiefly near the underlying syenitic rock. Mining for copper is not now carried on to any extent, the deposits being worked principally for the arsenic and sulphur they contain. At Tsiklova, the pyrites are largely mixed with argentiferous mispickel. Occasionally grey copper occurs mixed with blende, iron pyrites, and a small quantity of gold. The mines of Schmollnitz, in Upper Hungary, are of rather more importance. The annual production of copper in Austria is put down at 3,000 tons.

Germany, Prussia, — Passing northward by the Erzgebirge, where copper is to a small extent mixed with the other ores, to the Prussian province of the German Empire, the principal

' Mining youmal 1877, p. 532 ; J. L. Thomas, Mines tf Rio 7tn/o,

Mining- Journal September 1877, et seq.

122 Metalliferous Minerals And Mining.

mining district for this metal is that of Mansfield. Here the ores lie near the junction of the Permian with the New Red Sandstone strata. The deposit is a cupriferous bed, from two to three feet in thickness, which stretches for miles across the country. It consists of a bituminous marly slate, throughout which fine particles of grey copper containing silver are plentifully disseminated. Copper pyrites also occur in regular veins in similar strata near Canisdoif in Lower Silesia.

In the north-west comer of Nassau near Dillenburg, copper mines have been worked for many years. The strata apparently belong to the base of the Devonian group, and consist of an alternation of schaalstein — variable kind of rock ranging fi-om greenstone to slate, and black slates with eruptive rocks. The chief veins run NW. to SK with branches running obliquely to their course. The larger lodes are from six to seven feet wide. They traverse the whole series of strata. They are unproductive in the black shale, are moderately productive in schaalstein containing an admixture of calcareous spar, more productive in the same rock when it is of a green colour through the prevalence of chlorite, and most productive when the schaalstein is impregnated with iron.

The whole German Empire produces about 3,000 toils of copper yearly.

Norway.* — Far to the north-west, in northern Norway, in laL 70°, are the copper mines of Alten. The strata apparently belong to the Lower Cambrian group. They consist of dioritic and homblendic rocks. The copper ore deposits are found in these rocks, and do not extend into the slaty rocks with which they are interstratified. Adjacent to these mines are those of the Rai pas Vara mountain, where a group of veins traverse a half-crystalline limestone in the same geological group. In the upper part of these veins gossan with the arseniates and carbonates of copper prevails, but in depth the ore is the variegated. The lodes cease to be productive when they pass into the slates. The production of copper in Nor'ay and Sweden combined may be taken at about 3,000 tons.

Ann, des Mines (5), iii. ; Whitney's Metallic WeaUh,

Sweden. France. 1 23

Sweden. — The copper deposits of Sweden occur in similai strata to those of Norway, and are found under the similai varying conditions. The important mines of Falun are worked in a great inverted cone of copper ore, as shown in fig. 46.

The containing rock, 1 1, is a grey quartzose mass, divided into little ovoid masses by curving belts of chlorite. The centre of the cone, 2, is made up of iron pyrites, around which, in 3 3, there is an encircling mass of copper ore, which

averages, after sorting, from 3i to 4 per cent, of copper. At Areskuttan and Gustavsberg, the ore is found in ' fahlbands.'as copper pyrites spread throughout crystalline schists, the average yield of the ore being about 4 per cent, of metallic copper. In some of the Swedish copper ores silver to the extent of so to 30 ounces to the ton is found. In some recently discovered deposits in a white limestone in North Norway no less than 3,000 ounces of silver are found to the ton of copper ore. France,' — In France blue and red carbonates, with black

' Caillomc, Mint) mitalliqtits di la France.

124 Metalliferous Minerals And Mining.

oxide and copper pyrites, were formerly obtained near Lyons. They occurred in irregular beds at the junction of the New Red Sandstone with micaceous and talcose slates belonging to a much older group of rocks. The ores became pyritous as they passed into the slates. This district was famous for its beautiful crystals of azurite and red oxide, M. de Cailloux enumerates a great many districts where mines are worked for copper, but it is usually in conjunction with the ores of lead and silver combined, and there does not seem to be anything distinctive enough to require Special attention. The returns of the production of copper for the year 1869 include pyrites, which together gave a total of 92,519 tons, the proportion of copper probably not exceeding 2,000 tons.

Chapter Xvi.

COPPER-canHnued,

British Isles — Cornwall : Geological Structure and Characteristics of the Mining Districts of the county — Special Features of Lodes — Dolcoath Mine — History of Copper Mining in the West of England.

British Isles. — We again cross to the British islands, which, for their size, are the greatest copper-producing countries of the world. The total number of mines making returns of copper in the year 1877 was loi. These gave an aggregate of 79,252 tons of ore, of the value of 317,186/. 7. 7//., or an average of slightly over 4/. per ton. The ore gave 4,694 tons of metallic copper, of the value of 392,300/. This would show an average of about 17 per cent; but there is included in the total of the ores nearly 1,000 tons of regular, deducting which the percentage would be materially reduced.

Of the 10 1 mines, 65 were situated in Cornwall, which coimty contributed 43,016 tons of ore ; the average price for the year being 4/. 17X. per ton, and the average production to the ton of ore per cent The average standard price ot metallic copper was 1 13/. 8j. per ton. At the present time the price is only about three-fifths of that amount In 1879 the production of copper ore in the British Islands was 44,213 tons.

Cornwall, — From its situation on the south-west of Great Britain, from the number and importance of its copper mines, and from the scientific interest attaching to its minend deposits, Cornwall deserves our first and special attention.* The county forms the south-western promontory of England, and it will help

' Hunt, Mineral Statistics of Great Britain and Ireland 1 877.

' Pryce, MinenUogia Comubiensis ; De la BIche, Report on the Geology of Cornwall and Devon ; tnvrofA Metalliferous Deposits ; Cornwall Poly* technic Society Reports ; Moissenet, Etudes riches parties Gisements de la Cornwall (recently translated by Mr. Collins, F.G.S.).

126 Metalliferous Minerals And Mining.

EDgl[>h

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Kun Foway, Coi

Geological Structure Of Cornwall. 12;

US to understand both its copper and tin deposits if we now try to gain a clear idea of its geological structure.

its centre, or thereabouts, from Launceston to Land's End, there are four great bosses of granite. Passing north-east into Devon, the great granitic mass of Dartmoor makes a fifth ; and if we extend the line south-west to the Scilly Isles, these form a sixth.

Following these granitic masses from the north-east to the south-west they occur in the following order : i. Dartmoor ; 2. Between Bodmin and St Austell ; 4. Between Truro, Redruth, and Marazion; 5. The promontory of Penzance and Land's End ; and, 6. The Scilly Isles. The section, fig. 47, from the Bristol Channel to the English Channel, from northwest to south-east, across the second of the above granitic masses, will enable us to understand the geological structure of the country, and to fix the position, stratigraphically, of the different mines. It will be understood that parallel sections carried through the other masses would show the same general results.

Subject to local and minor variations, the structure of these granitic masses is very similar ; it is a mixture of quartz, mica, and felspar, the felspar often prevailing, and when occurring in large 'crystals giving the rock a porphyritic character. Nests of schorl frequently occur which vary greatly in size, and the change from ordinary granite to schorlaceous, is observable by the gradual disappearance first of the mica and then of the felspar, leaving only a mixture of schorl and quartz.

Resting immediately upon the granite, and observable around the outlines of the masses where not covered by the newer rocks, is a series of thick-bedded micaceous and talcose slates, which become in places chloritic Micaceous slate is the prevailing form of rock, and this becomes gneissic here and there by the addition of felspar. In their upper portion these slates become interstratified with, and are finally succeeded by hornblendic rocks, composed chiefly of lustrous hornblende and felspar, and which have not the slaty structure of the group below. These rocks underlie, and gradually pass upwards into serpentine rock, as at the Lizard Point The serpentine, however, as is the case with similar rocks elsewhere, sometimes protrudes through the

128 Metalliferous Minerals And Mining.

homblendic rocks and then overflows them in roughly regular beds, the homblendic rock being greatly changed at the point of contact The change in structure from one rock to the other is usually very gradual.

Above these homblendic rocks, with their emptive and rudely -bedded metamorphic rocks, comes a thick series of grey argillaceous shaly slates, which are in places tinged with red. Where the series is most complete, these slates pass upwards into alterations of slaty with arenaceous and calcareous grits, varied by slates tiversed by quartz veins.

The direction or strike of the beds follows the line of the upheaval of the granites, NE. to SW. ; the dip being, of course, at right angles on both sides of the granitic masses. For the most part, the lower groups of slaty rock are highly metamorphosed, and it is difficult to assign them to their proper geological group. In maps they are all included as Devonian, which is, I think, with all deference to other observers, a mistake. My own interpretation of the ages of the strata I have just described is this : The micaceous and talcose slates belong to the Cambrian ; the homblendic slates with the serpentines and porphyries to the Cambro-Silurian ; the argillaceous slates to the Silurian, passing gradually in their upper portion into the Devonian. In the last formation is comprised the bulk of the grits, slates, and sandstones that in South Devon overlap the older groups of rocks, and rest immediately upon the granitic mass of Dartmoor. The granitic masses, which are probably part of a vast sheet or mass that underlies the whole series, seem to have been protmded through the overlying strata towards the close of the carboniferous period. Compelled as I have felt myself to subdivide these Cornish strata which hitherto have been grouped as Devonian, and to assign to the lower parts of them ages older than the one that has hitherto been accepted, it has given me great satisfaction to find that Mr. J. H. Collins, F.G.S., of Tmro, has in the course of his researches arrived independently at the same conclusion.

Besides the dykes 'elvans* of eruptive matter, mostly granitic, that traverse them, the whole of the strata described, granites included, appear to be traversed by two chief setts of

Epochs Of Disturbance In Cornwall. 1 29

cracks or fissures. One sett, the oldest, ranges within 25 degrees either side of due east and west. The other, which we know to be the newest, because the cracks have cut and displaced those of the older, range 30 degrees on either side of a direct north and south line. The first sett of fissures are those which are most rich in metalliferous ores, especially those of tin and copper, and it has been obser\''ed that their direction coincides generally to that of the elvan dykes. The NE. and SW. lodes also correspond to the strike of the strata ; but as the NW. and SK lodes are equally rich, the wealth of the lode does not appear to have been affected by its coincidence with the strike of the beds.

Altogether five main epochs of intrusion, firacture, or disturbance may be defined in the strata of Cornwall : i. Those formed in the granite either before or at the time of its protrusion through the slates. 2. That of the elvan dykes and courses that traverse both granites and slates. 3. That of the east and west tin and copper lodes. 4. That of the cracks and faults having a general north and south direction ; and, 5. That of the east and west slides which may be of recent date. Each of these groups has its own system of minor fractures, diverging from it at all angles, like cracks firom a central fracture on a window pane. Moissenet, in the work already named, endeavours to solve or determine the directions of these cracks by mathematical problems, but it is doubtful whether, from the extreme intricacy of the rules, the number of the exceptions, and the cumbersomeness of the process, his methods can ever be of practical use to ordinary miners.

The great mining districts of Cornwall and Devon are grouped around the granitic masses, the most productive mines being worked on the north or south flanks of these, along the centre of the line of upheaval extending firom Penzance to Dartmoor, and where of course the oldest strata next to the granite are at or near the surface. The zone of productive mines Extends seven or eight miles on each side this line of upheaval, making a belt about fifteen miles wide.

Generally speaking, the district around each granitic boss

130 Metalliferous Minerals And Mining.

has its own mineral characteristics. Beginning on the northeast, the western side of the Dartmoor mass is cupriferous. Dartmoor itself is stanniferous. Around the little boss of Callington the strata are both cupriferous and stanniferous, while north-east at Sidford, and south at Beer Alston, are the silver lead lodes. The mines around the granitic mass between Launceston and Bodmin are both copper and tin. There are also a few silver lead mines. On the SK of the granite of St. Austell, the deposits are chiefly copper — the Fowey Consols Mine being here. Through the remainder of the circumference the mines are chiefly tin. The next district, that around the Redruth, Gwennap, and Penrhyn mass, is the great locality of the copper mines of Cornwall, although on the NW., near Gwinnear, tin is largely present, and silver ores have at times been profitably worked. The extreme western district, from Marazion to Land's End, produces tin, with a little copper worked at a few of the mines. Taking one of these granitic masses, with the strata described lying in their completeness around it, we find the centre (if the granite be favourable) and the innermost circle or lowest beds of micaceous and talcose slates to be stanniferous. Next, where the slate group passes into the homblendic rocks, a circle of cupriferous mines ; and third, where the clay slates rest upon the homblendic and metamorphic rocks, an outer circle of plombiferous deposits. If, therefore, a well-defined lode could be followed downwards from the surface of this outer circle, we should find, first, in the clay slates deposits of lead ore containing silver ; next, when we got down into the homblendic rocks and portions of the micaceous slates, copper ores ; and, finally, when we approached the contact of these last with the granite, and in the granite itself, the ores of tin. Scarcely any mine is deep enough to show the sequence of the whole three metalliferous deposits, but there are numerous examples of lodes containing copper ores in their upper portion and tin below, as I have described. Before we have finished our inquiries we shall see the accord of this arrangement with the universal stratigraphical arrangement of the various metallic ores.

Copper Mines Of Cornwall. 131

The variations, therefore, in the character of the mines around these successive granitic masses, depend chiefly upon the age and nature of the strata thrown near the surface.

Bearing these considerations in mind, I proceed to observe that, although copper ores are found in all the mining districts described, the chief mining centres for copper in Cornwall and Devon are those near the town of Tavistock on the NE., and Redruth on the SW. Near the former town are the Devon Great Consols and the South Caradon Mines, and near the latter are the Cam Brea, Cremier and Abraham, Crofty, South Huel, East Pool, West Seton Huel, and West Tolgus, the great copper-producing mines of the two counties.

Copper ores prevail in the lodes that have a general east and west direction, and any deflection from the direction of a productive part of a lode influences its productiveness usually for the worse. The usual dip of the lodes is about 70 degrees from the horizon towards the north. They traverse both the granites and the overlying slates. Their average width in the slates is 7 feet, but they open out great widths, as, for example, 20 to 42 feet at the Devon Great Consols, and they contract to an average of 2 feet in the softer granite, and dwindle down to mere threads as they pass through hard felspathic, granitic, and porphyritic rock elvans, in passing through which they are often split up into a number of thin veins. This contraction of the lodes in hard rocks has occasionally led to the abandonment of mines. Thus Cam Brea Mine was abandoned fifty years ago, through the approximation of the walls of the lode to each other. Some more hopeful adventurers subsequently resumed work, and followed the thread of the lode until it expanded, and was found to contain a rich bunch of ore. The produce of this mine in 1876 was 1,174 tons.

The lodes are filled chiefly with the fragments and redeposited grains of the rocks they traverse. A fresh combination of substances has, however, usually taken place, so that they are found in layers following the course and parallel to the walls of the lode. The silica frequently assumes a crystalline

K a

132 Metalliferous Minerals And Mining.

form, the crystals coloured by fluorine pointing across the lode (as shown in figs. 48, 49, 50, adapted from De la £6che), and the clay lying in layers between.

Copper ores do occur in the

basement granitic rock, and in the

newer protruded granitic rocks, but

they are most abundant in the slates

Fio. 4J.— LoD Hu Rbobutm. not far from their point of contact

I. Quart. Bd mujie BoonpH. (he metamorphic rocks and

3, Quani, ith yellow copper ore. granites. In the slates also copper

4, Qurfz mud purple ? , , . . '.

s. Qmra. 6, Qumnz, villi iprigi IS more plentiful m some varieties

"pp" 0"- jijj others. The favourite colour

of the miners is blue, of a light

colour and of a fairly compact

structure, but not too hard. In the

Gwennap district, for example, the

lodes became poor as they passed

into red slate. In the Old Godol-

phin Mine tlie lodes were rich in

pale blue slate, but poor in black.

I suiphidw or copper uiii line A Fowcy Consols Mmc the

' mmboiqam. 3, HudeMdciay. pitch OF dip of the ore follows that

5, Lunge comh d qMiti. wiih cop- ,, , ,

permdbiaideoiieKhBdoofii,* of the bluc beds of slate rock, and

'' " " Pryce ' says that ' of all the killas

' the cinerous or pale blue is the most

desirable as the enclosing stratum

of a copper lode.' Where the strata

is thus favourable the lodes are

productive of copper high up in

the series, some of them yielding

-Fio. so.— Loon KBAB Bbkacui. copper immediately under the fos-

?Ii£" ""h °f """wit ?T sili'rous beds.

<raeMhiLdt.jiu.d ';. suipSide Fig. 5! is 3. reduction of an

of copper mixed wiin&liEileqiuiru. u , e 1

old plan of the workings on a ' SlinerahgUi Camuiunn's.

134 Metalliferous Minerals And Mining.

contra lode at the Dolcoath Mine/ and is interesting as showing the proportion of productive ground in the slaty rock and in the granite, as shown by the amount of stoping done in the two rocks. The lodes are usually poor in the greenstones, or

irestones,* as they are locally called, of Cornwall. It is in soft and easily decomposable granite that the lodes bear ore when they do at all in that rock. They are often productive when approaching an elvan course, and sometimes within it; but this depends upon its particular lithological character, and usually dykes of hard, compact, intractable rock are barren, and the lodes pinched. Ore is usually plentiful where two lodes meet at an acute angle, and poor on the obtuse or broad side of the meeting point

The prevailing ore of copper in the region is the yellow, or bisulphide. Next to this comes the sulphide, or grey and black ore of the miners, and it is in this form that copper is found near the surface and by the cross courses. Usually the yellow ore holds out in depth. The more uncommon ores are the red oxide, the carbonates and silicates, and the arseniates. Phosphate of copper is rarely seen. The common metalliferous associates of the copper are the sulphides of iron and zinc, which occasionally occupy the whole of the lode. Arsenical pyrites are also found, especially in the Tavistock district, and throughout Cornwall they are considered the precursor of copper. Sulphide of lead occurs in small quantities. The figs. 48, 49, and 50 illustrate a frequent arrangement of the metallic ores in Cornish lodes. For some depth from the surface the lodes are made up chiefly of gossan or earthy brown iron ore, containing the black ore of copper — the sulphide having been largely replaced by oxygen. Lower down, beyond the reach of the atmospheric influences, the ore becomes a bisulphide, and it is this yellow ore tliat usually holds out in depth. In the granites and near the surface there are numerous

vughs ' or cavities, which are lined with crystals of quartz often

Etymology : Welsh, dol a meadow ; coch red : Red Meadow, from the soil being tinged red with the ores of iron and copper.

Rise Of Copper Mining In Cornwall. 1 35

coated with native and ruby silver. In slate such cavities, when they occur, are mostly coated with iron and copper pyrites.

Copper raining in the West of England is of comparatively recent origin. Carew, writing about the year 1600, says that copper is found in sundry places, but he could not find that it was profitably worked. At one mine he knew that the ore was shipped to be smelted. For years after this time copper ores were neglected, roads being mended and walls built with them. About 1690-5, a Mr. Coster, of Bristol, with some other persons, went into Cornwall and bought copper ore for from 2/. JOS. to 4/ per toa Competition arose, and contracts were made for the entire produce of mines at 5/. per ton. Some years subsequently, a gentleman from South Wales is heard of buying a lot of 1,400 tons of ore, that had been lying at a mine for a long time, at 6/. 5. per ton, and another lot at Roskean for 7/. per ton.

From about the year 1726 we get regular returns of the quantities of ore and the prices realised. William Pryce, wTiting in 1778,* gives the following particulars, which are interesting for comparison with the present annual yield and price:

Dates

Total yield for the ten years

Average prices

Ten years. 1726 to 1735 1736 to 1745 1746 to 1755 1756 to 1765 1766 to 1775

Tons. 64,800

98,790

169,690

264,273

£ s. d.

7 Is 10 7 8 6 6 14 6

The quantity of copper ore raised in the counties of Devon and Cornwall, in the year 1876, was 59,292 tons, or double the quantity raised a century ago. The average price per ton of ore for the five years ending 1876 was 4/. i is, 4//. The average quality for the same period was per cent of metallic copper, or slightly over 13 '6 per unit ; the average standard for metallic copper for the same years being loiA $s. 2//. per ton.

Chapter Xvii.

COPPER—continued.

Cupreous Sandstones of Cheshire and Salop — The Limestones of Salop and North Wales — The Parys Mines of Anglesea — The Copper Turf of Merioneth — Copper in Carnarvonshire and Cardigan — North- West of England — County Wicklow in Ireland.

Cupreous Sandstones of Cheshire and Salop} — Of a different age and character are the copper deposits in the Lower Keuper beds of the New Red Sandstone of Cheshire and Salop. At Alderley Edge, in Cheshire, a copper mine has been successfully worked for some years. Its production in 1875 was 8,336 tons, and in 1876, 7,328 tons. Through the recent low price of copper, however, the mine has had to be given up. While I write the plant is being sold and the mine abandoned. The deposit consisted of a portion of a sandstone bed impregnated with copper. The dip of the bed was very steep to the SW., the strike being, of course, at right angles to the dip. The ores were the blue and green carbonates, of a poor quality, from to 3 per cent. The ore was associated with earthy cobalt ore, and the bed partook largely, as may be supposed, of the character of the adjoining rocks.

Of a similar character was the deposit that was worked at Eardiston, near West Felton, Salop, about thirty years ago. This also consisted of a cupriferous bed, now showing welldefined boundaries, separating it from the adjacent sandstones, and then graduating into them, being really a mineralised zone of sandstone At its outcrop, it contained a good deal of brown earthy iron ore. It varied in thickness from a few inches to five feet It contained cavities lined with mammillary mala-

See also Kenwood's Metalliferous Deposits,

Copper Deposits Of Cheshire And Salop. 1 37

chite, and was richest in copper ore near its upper and lower boundaries, where it abutted on faults in the sandstones. It was subdivided into four layers, thus —

1. Red sandstone sprinkled with malachite and grey copper ore.

2. Sandstone with grains of malachite.

3. Ferruginous sandstone.

4. Ferruginous sandstone, largely mixed with malachite and with grey copper ore.

The ores yielded '008 to '025 of metal, and the aggregate production from 1841 to 1843 is given at 2,500 tons. The deposit was followed down its dip for sixteen fathoms, when a tough clay filling a line of fault cut it off.

Sandstones of the same age in the Peckforton Hills of Cheshire, that range between the two localities just given and those that overlie the Coal-measures

of Cannock Chase, are m Fig. 5a.— Sectioh of Limkstonb Strata and , Cupreous Shalb Bed at Pamt, near Os-

places similarly impreg- westry, Salop. nated with copper.

Limestones of Salop and North Wales, — The Carboniferous limestones that range from Shropshire to Anglesea have been worked at various times for ores of copper. Old mine works, attributed to the Romans, abound on L.lan3anynech Hill, which is partly in Shropshire, and attempts at mining with varying degrees of success have been made of late years in the same locality.

Fig. 52 illustrates the manner in which the deposits occur at this end of the range : 1 1 are the ordinary pale-coloured limestones of the lower division of the series ; 2 is a considerable thickness of brownish yellow sandy limestone, full of small cavities lined with crystals of quartz and carbonate of lime, beautifully variegated with the sulphides, but chiefly with the

138 Metalliferous Minerals And Mining.

blue and green carbonates of copper ; 3 is a thin shale bed, impregnated with the above ores to the extent of 2 J and occasionally 3 per cent — the ores being richest and most abundant underneath the cracks, 3 3, that run up into the limestones, as

at AAA.

At the NW. end of the range, on the mainland, is the Great Ormes Head. Mines were successfully worked in similar deposits to those just described until within the last twenty years. The same cavitous limestone, impregnated with copper, and the underlying cupriferous shale bed were present there. The accumulations of copper ore were found and worked along the course of a flat fault, known as the Hanging Mawr.' Crossing this fault from NW. to SE. was another sharper fault, called the Cyllell, or Knife, and near the point of the intersection of these two the largest deposit of ore was found. Both at and the Ormes Head the source of the copper appears to have been the overlying cupriferous limestone beds, from which the ore had been carried by the infiltration of water into places favourable for its deposition.

Limestone of Staffordshire and Derbyshire. — An important copper deposit was, at the close of the last century, worked at Ecton, near Hartington, on the borders of these two counties. It occurred as a succession of pockets connected by fissures, which were followed to a depth of 1,320 feet The limestone was of a blackish brown colour, and the beds were much broken and confused. The ore was chiefly sulphide, and was often very rich, yielding, it is said, from 40 to 60 per cent, of copper. The ores were also noted for their great beauty of form and colour. The mine was a productive and profitable one, and it employed at one time about 1,000 work people. The ores were associated with carbonate of lime and bar3rtes.

Anglesea. — Parys Mines, — From the Ormes Head we look across the eastern end of the Menai Straits to the northern comer of Anglesea. Here, in Parys Mountain, near the town of Amlwch, the most important copper mine of Wales has been worked for about a century and a quarter.* Previous to this

Pennant, Tour in North WdUs,

The Parys Copper Mine, Anglesea. 1 39

time there were traces of old mines, the remains of furnaces, and lumps of smelted copper with traces of lead ore lying about, which led Alexander Fraser, a mining adventurer from Scotland, to select the locality as the scene of his explorations. Shafts were sunk and ore discovered, but the operations were stopped by the influx of water.

A lease of the ground was, two years afterwards, included, much against the will of the lessors, Messrs. Roe & Co., in the lease of other mining ground in Carnarvonshire, by the owner of the two grants, Sir Nicholas Bayley. Ore was again reached, but worked for some time at a loss. The lessees gave their agent orders to stop the works, but he, as a final effort, divided his men into ten gangs, and put them to make trial holes near a spring strongly charged with copper. In two days better ore was struck at a depth of only seven feet from the surface. From then until now the mine has been successfully worked, the profits during the interval being estimated at not less than 7,000,000/. The production of ore in 1875 was 2,910 tons, and in 1876, 2,512 tons. At present, with the exception of the precipitation pits and the carrying on of some deeper explorations, the mine is, owing to the very low price of copper, lying' idle. The mountain in which the mine is worked is supposed to take its name from Robert Parys, who was Chamberlain of North Wales in the reign of Henry IV. The adjacent mine to the east is called the Mona, and a recent discovery of ore under the old workings is likely to restore this mine to its old prosperity.

Figs. 53, 54, and 55, reduced to scale from the working plans of the Parys mine, will illustrate the position and nature of this important deposit of copper ore.

Fig. 53 is a section from south to north across the strata, which are tilted up at a high angle from 60 to 70. i is a thick series of clay slates, traversed by veins of quartz and felspar, and contains layers of the same, as well as of greenstone ; 2, a thick mass of rock that varies in composition along its course from slate to huge bodies of quartz, the whole mixed up with chlorite

140 Metalliferous Minerals And Mining.

toid disintegrated felspar, with earthy brown iron ore, and con-

Ncntli IHicoimy

CunE'Y'Dd

Fic SJ.-PAI1YI Mike; SicTioM aches Stbata ahd Dmosits.

t-vining the great copper deposit ; 3 is a thick belt of quartzose

Strata Of Parys And Mona Mines. I41

rock, often cherty in character, that fonns the crest of the

mountain J 4, a series of

beds similar to No. 2 ; and

in 5 we have the series

surmounted by a great

thickness of clay slate.

The whole series belong

to the Cambrian group of

strata, probably the upper

part of the Lower Cambrian. The mineralised

portions are Nos. 2 and 4.

In two there has been a

thick succession of mineralised beds, and in 4 only two such beds. The beds of No. 2 have been worked as an open quarry, of which a cross section is given in fig. 53, and a longitudinal section in fig. 54. A reference to fig. 55, .1-3 which represents the North Discoveiy lode, will illustrate the way in which the copper ores were distributed throughout the thick series of similar beds that have been quarried % from the great open cast The mineralisation of the beds is continued to the east, where, on the other side of the cross course, I which is an upthrow to '

the east, they are worked P'=- uim

. .. i,- - ... OH GaiiT O

mtheMonaMme. It will

142 Metalliferous Minerals And Mining.

be observed that the mineralisation ceases on the west It is, however, renewed in a short distance in another form, as will presently be explained. Whether the ores will continue in depth

FMi jj.— Pahts Mikb: Section of Workincs oh North Discovbbv Lode.

or die out in a wedge form will be proved as the lowest level is brought into the ground under the open shaft. At present there are slight indications of ore. In revising these pages for

Ores Of Morfa Ddu. 1 43

a new edition, I am glad to add that now, April 1880, the yield of the lode in this lowest level is given as from to 4 tons of copper ore per fathom.

The copper ores are distributed throughout the mass, as shown in the section of the North Discovery lode. The ores consisted of nests of earthy black ore near the surface, passing into yellow pyrites in depth. Rarely there are small quantities of native copper, and throughout the mass there are numerous cavities lined with crystals of copper and sulphate of lead. The ores are classified for commercial purposes thus :

Halvans, — Containing per cent of copper, and a good deal of sulphur.

Poor Ore, — 3 to per cent of copper, and much sulphur.

Ordinary Ore, — 6 to 7 per cent of copper, some sulphur.

Good Ore. — 20 per cent of copper.

Precipitate, — This is formed from the water pumped and flowing from the mines, and from the rain water that has percolated through the waste heaps. It is all arrested in a very complete system of long square pits. Waste iron and tin clippings are thrown in these, tlie sulphuric acid that is in the water seizes hold of them, the particles of copper suspended in the water fall to the bottom of the pit, and, mixing with the iron dissolved by the sulphuric acid, form a precipitate ranging in value from 15 to 30 per cent of copper. The spent water also is caused to flow through a long series of tanks, in which the earthy brown iron ore is finally precipitated as ochre, for which it is sold, the water flowing off as pure as is practicable. The ochre is sold at prices ranging from 1 1 j. to 2 1 J. per ton.

About a mile to the west of the Parys Mine, at Morfa Ddu, where what seems a continuation of some of the beds worked in the great open cast are crossed by an east and west course, is a peculiarly mineralised deposit, locally known as bluestone. This bluestone requires special careful chemical operations to extract its contained metals. As proved by Messrs. Hills

144 Metalliferous Minerals And Mining.

& Son, of Amlwch, who have worked it, it is composed as follows :

Copper 2 per cent.

Lead i6 ,,

Zinc 32 II

Silver 7 ozs to the ton.

Sulphur, iron, antimony, and manganese in small proportion.

Copper Bog of Merioneth. — The mention of the coppercharged water at these mines leads to a notice of the copper bog near Moel Hafod Owen, west of Rhobell Fawr, near Dolgelly.

The turf filled a hollow in the hills, the strata of which are talcose schists, felspathic rocks, and greenstones of the Upper Cambrian group, which are dotted and intersected with nests and strings of copper pyrites.

The water passing over and through these copper impregnated rocks, flowed into the bog, the moss of which thus became charged with carbonate of copper. Ore to the value of many thousands of pounds was formerly extracted by burning the turf in kilns, and separating the copper from its ashes. The deposit is interesting as a recent example of the way in which some of the stratified mineral deposits we are considering became saturated with metallic matter.

A considerable attempt has been made, with much skill, and by the aid of excellent machinery, to work one of the copper pyrites lodes of the district at Glasdwr, near Dolgelly, but from the poorness of the ore, about per cent, although by careful dressing it was brought up to 6 per cent, the mine is at present idle. The matrix of this ore is a slaty bluestone, containing numerous ramifications of sulphide of copper and iron pyrites, with which is associated a small quantity of silver, less of gold, and some lead.

Carnarvonshire and Cardigan. — Lodes charged with sulphide and bhie and green carbonate of copper traverse similar strata, and run up into the overlying Llandeilo beds in

Ramsay, dology of North fVaUs,

Copper Mines Of Ireland. 1 45

the country between Drwysycoed, where there is an ancient copper mine, and the region of Moel Hebog, Beddgelert, and Snowdon. Old mines, where considerable work has been done, dot the hillsides. The most important copper mine in Carnarvon at the present time is TanybwlcL Its production of copper ore in 1878 was 595 tons, of the value of 5,500/.

The lodes are about four feet wide, and have usuaUy been worked by adit levels. With the introduction of tramways into the district, some of these lodes in ordinary conditions of trade may yet perhaps be worked to profit Copper is the prevailing metallic mineral of the region, and the lead lodes are charged with it This is also true of a smaU portion of the lead district of the county of Cardigan, as at Esgair Ffraith and South Darren Mines, near Abeiystwith. These two mines produced m 1878, 306 tons 15 cwt of ore, that gave 31 tons 10 cwt of pure copper.

North-West of England.' — The last remark applies to this region. Copper pyrites are found in similar strata, and 1,007 tons were raised at the Coniston Mine, one of the oldest in the north-west of England, in the year i$76. The strata here are green slates and porphyritic rocks, which are traversed by six east and west ore-bearing veins, through which, a quarter of a mile apart, are two great north and south faults, which displace the east and west lodes.

The most productive of the latter is known as the Friddle. At the depth of 100 3rards from the surface a large body of ore was struck, which has been followed downwards for 200 yards. A good deal of the richest ore has been obtained from a similar lode known as the Paddy End vein. The ore is chiefly copper pyrites, with occasionally some of the other forms of ore. Other mines of the district opened for copper have proved more productive of lead.

Ireland: Co. Wicklow. — In 1876 Ireland produced 5,651 tons of copper ore, of the value of 29,213/. Zs. Cd, or about

' Postlethwaite, Metis ami Mining in the Lake District..

146 Metalliferous Minerals And Mining.

5/. los. per ton. In 1878 the production had fallen to i,8io tons, of the value of 9,661/ 17;. lod.

Fig. ISA.— Mom of Occvihci or Duoeiti or Corru ahd Iron PniTO AT

Old Ballvhuitaqh Uihl

i"a lad jnrdi boot.

ti Oujtltla. cc. Colder pjrriie*. IimpTrii**- Great twndi of coppa on.

Althou not now the largest producers of copper ore, the

mines of Ovoca, in Wicklow,' are

interesting as showing us great

I masses of strata, penueated with

t' copper and sulphur, like those

f just described in Anglesea.

/ The basement lock of the

C country is a grey granite, which,

[, where most productive of mine-

k lals, is mixed with green steatite,

p and occasionally there are large

f crystals of felspar that give the

I rocic a homblendic appearance.

Fig. ss.-9mctu. or LoDi at tio- The granite is overlaid by a cou-

oiiT Hois, Otoca. Wicklow. siderable thickness of micaceous

111. CooDflr lode*. V. Inmprntcaii" , i - i - - j

wUc if Bakofdiicnucoiound slate, which in Its turn IS capped

by a great thickness of clay slate,

the series presenting a simibrity to the succession of strata in

' Smyth, JifiiK! af and Wattrjord,

Wicklow Copper Mines. I47

Cornwall The copper has been most plentiful near the junction of the micaceous slates with the granite. The strata range from N£. to SW.y and dip to the SK at an angle of about 50 degrees. Fig. 55A shows a conmion mode of the occurrence of the ores, the deposit though not coinciding with, yet following roughly the dip and course of the bedding. It represents the nature of the copper and sulphur deposits at the Old Bally Murtagh Mine; and fig. 56, from Sm3rth, is a section of a similar deposit at the mines of Tigrony, on the banks of the Ovoca, showing strings of copper ore and a sulphur course running side by side and coinciding generally with the bedding. The whole width of the metalliferous beds here is about 40 yards, and the copper ores range in value from 4 to 8 per cent

CHAPTER XVIir.

COPPES—eantmutd.

Copper Deposits of North-Eastem America— Nova Scotia to Carolina — Mississippi Volley, Wiscon — Lake Superior — Canada.

North-Eastern America.' — Deposits of copper have been

found and worked to some extent in Newfoundland and in

Nova Scotia,* the production of the latter province being, for

1877, 285 tons, an increase of 240 tons on the previous year,

„ J. .. Mines are also in ope-

I J I II la I ration at various points

along both sides of the

Appalachian mountains,

from Maine to the Caro-

I linas. One of the most

I important of these is near

the town of Manchester,

in Connecticut, where a

deposit of malachite has

been worked at times

I since the middle of the

Fin. sj.-SacnoK tub Cohiifdoui Bn> at last centUTy. Other itn-

Doixv HiD Mini. Mabtuhd- portant mines of these

1, JJineiiiHie, with rtiiu, 100 ft. thick. ' r.. . i. l

Eastern States have been opened in Maiyland, and fig. 57, adapted fi-om Whitney, will show the character of the deposit at what was called the Dolly Hide Mine.

There is a band of crystalline limestone 100 feet thick,

' Whitney, Mitidlk Weallk of tht United States.

' Gilpin, ' Recent Discoveries of Copper in Nova Scotia,' Quarlirly yeurnai Gioliigical Sacitly, November 1S77.

Copper Mines Of Tennessee. I49

interstratified in places with slate, the whole of the beds being nearly perpendicular. In the limestone are numerous roughly parallel irregular beds or segregations of copper ore. This is mixed with quartz, coloured brown by iron and manganese. In depth, or along the course of the bed, argentiferous galena takes the place of copper, the galena yielding 45 to 50 ounces of silver to the ton of ore.

Besides deposits in the older Cambro-Silurian rocks and Carboniferous limestone, there are, along these Eastern States, copper deposits associated with the New Red Sandstone. These consist first of contact deposits lying between the Sandstone above and porphyritic rocks below, and secondly of cupriferous beds in the Sandstone itself, like those of Cheshire and Salop. In New Brunswick such deposits are associated with Coalmeasure fossils.

Another important group of mines is successfully worked by the Union Consolidated Mining Company of Tennessee, near Ducktown, in the north-eastern comer of Tennessee, and on the western side of the Alleghanies. About 1,000 men are employed, and the production is about 2,500 tons a year. The ore is black oxide, which was discovered in the year 1849. It yields on an average 25 per cent of metallic copper. In depth it changes to yellow sulphide, with a yield of 6 per cent, of fine copper. The deposit varies in width from 15 to 60 feet, and is probably a mineralised bed of the same age and character — micaceous and homblendic rocks — as those of Anglesea. Similar deposits occur in Alabama.

Dr. Sterry Hunt,* while admitting the general coincidence of these deposits with the strata, regards them, from their internal structure, as true fissure lodes. The massive chalcopyrite and other sulphuretted ores are traversed by larger crystals of hornblende and which are often broken across and the cracks filled with sulphides. There are, however, micaceous beds in the immediate vicinity of these lodes strongly impregnated with copper. So that there are both beds and lodes.

Engineering and Mining ToumalofNew Yorh August 1877, p. 109.

Iso Metalliferous Minerals And Mining.

Passing up the Mississippi Valley, a copper deposit is found at Mineral Point, Wisconsin. The ore occurs in a fissure in Cambro-Silurian limestone. The fissure is about 14 feet wide, and is filled with gossan to the depth of 15 feet In the gossan are found lumps of the sulphide and carbonate of copper of all sizes up to 200 lbs. weight Below that depth the fissiure was filled with clay, with a little copper ore dispersed though it

Lake Superior Copper Region. — Pursuing our journey northward we reach the most important copper region of the North American continent, the southern shore of Lake Superior, about Kewenaw Point and Bay. There are traces of old shallow workings made by the Indians. The deposits of copper were also Imown to the Catholic priests who travelled in the region in the latter half of the sixteenth century. Mining operations by Europeans were commenced near the Forks of Ontonagon,

a 9 5 : ♦ i M 9 ♦

Fig. 58.—SBCT10N OP Strata in the Lake Superior Coppbr Rbcion.

z, Granitic rocks, Gnetssic rocks. 3, Greenstone and homblendic rocks, and coD' glomerates with interstratified slates. 4, Slaty rocks, with traps, &c 5, Potsdam sandstone— Lingula flags, a a, Place of copper depoits. b b, Place of ironstone beds.

in the year 1 771, by Alexander Henry, who does not seem to have been very successful. From this date the country was visited by military and scientific men, and by State officers, who were all surprised at the masses of native copper to be seen there, but who all concurred in the idea that the district was too remote for the ores to be profitably worked, especially considering the hostility of the Indian tribes.

In 1843 the country was ceded by the latter to the United States, and in the same and following years numerous miners, prospectors, and geologists, explored the region. Hundreds of permits or take-notes' were applied for ; the most unlikely localities were taken. The excitement grew. Speculation and Stock Exchange tactics flourished, the whole followed by the usual result — a collapse. Some good mines however remained.

The diagram section, fig. 58, will illustrate the geological

Lake Superior Copper Region. 151

structure of the country, and will show the position of ihe copper deposits, as well as those of iron, which we shall have presently to consider.

The lowest granite, i, passes upwards into gneiss ; 3, 3 are homblendic rocks and greenstones, covered by slates, calcareous in places, and interstiatified by felspathicand homblendic rocks ; s is a great thickness of what by its fossils is proved to be the Potsdam sandstone, the equivalent of our Lingula flags ; 3 B is an upward curve of the lower portion of the Tocks 3 and 4 a 4 a are continuations, in a somewhat altered form, of portions of group 4. They here consist of conglomerates, traps, greenstones, and slates, resting on a central ridge or upward curved mass of choridc and gneissic rock, and contain the copper deposit These consist of both mineralised beds and proper lodes.

The whole region has been grouped into four districts thus :

1. Keweitaw . 3. Ontonagon.

2. Isle RoyHl. 4. Portage Lake.

The section of Waterbury Mine (fig. 59) will show the dated order of the strata in the Kewenaw Point district, and one of the bedded deposits. "

The upper greenstone, i, is a compact crystalline trappean rock like dolerite. It has a thickness of 500 to 600 feet ; under it lies a bed of ash, often chloritic. Between this and the conglomerate 4. there is the Fj_SKTO,KATW.Ti..uyM™.,L*.f. ore deposit 3, containing „ ?I?™.'"- .

, . , , % I, Gthmoiw. s, QkHiic uli. 3, Copper ic-

thm sheets and particles of pou, wiiii tMn urHiu and tpcSi ofcopiW'

4, ConoiscnEft. s. AmyldaJaid it baifi of copper. reck. 6, bnit

The details of the beds yw" cmi™ ™i between the crystalline be. mn from tb duuii Kiwn oc uw EurIu greenstone, i, and the amygdaloidal greenstone, 4, vary in their passage westward

152 Metalliferous Minerals And Mining.

from this point, as the section at the Lake Eureka Mine, fig. 60, will show.

The amygdaloidal beds, 5 of fig. 59 and 8 of fig. 60, alternate with sandstones and shales, and form a group of strata 4,000 to 5,000 feet thick, and constitute the great copperbearing zone of rocks.

They are traversed at right angles to their strike by nearly , perpendicular lodes, which have a usual width of three feet, bnt which open out to ten feet wide or more. There are no cross courses, but as the lodes pass from one kind of rock to another, they are often bent firom a straight course. They

Fig. 6a — Sbction showing details op thb <Gkbbnstonb AND Amygdaloid at Eureka Mine, Lake Superior.

X, Greenstone, 500 feet thick. 3, Veins of quartz. 3, Reddish conglomerate. 4, Greenish conglomerate. 5, Hard clayey matter, with specks of copper. 6, Hard clayey matter. 7, Trappean ash. 8, Amygdaloid.

traverse the whole series of strata from the underlying gneiss and greenstone, 3 b, to the Potsdam sandstone, 5, of the section fig. 58. The gangues of the veins vary in the different rocks. In conglomerate the earthy minerals are chiefly calcareous, in which the copper is concentrated into large masses. In the fine crystalline amygdaloids, which are the most productive ore-bearing rocks, the lodes contain quartzose matters, mixed with variable quantities of calcareous spar and zeolitic minerals. Copper is most abundant when tiie lode-stuff is a crystalline and drusy quartz, intermixed with granular car-

Cliff Mine.

Is3

bonate of lime and prehnite. With the earthy minerals in most of the veins there are cemented brecciated fragments of the adjoining rock.

The veins seem lost when they pass up into the overlying Potsdam sandstone, and are not usually productive in the crystallising greenstone at the top of the sections, figs. 59 and 60, although they are close up to it

The copper is found native, in particles and masses of all sizes, from those of microscopic minuteness up to 200 tons in weight At the Cliff Mine, of which a section, adapted from

N27W

Pic. 61.— Section op thb Cliff Minb. Dark parts show ground sloped.

Whitney, is given in fig. 61, sheet copper often occupies the entire vein. No part of the vein is so poor as not to be worth taking down, the average production of copper per fathom being 761 pounds.

The lode was first discovered at this mine in the crystallme trap or greenstone at the top of the bluff.

Its course down the escarpment was marked by a depression in the greenstone. In this rock the lode was only a few inches wide, and contained native copper and specks of silver beautifully incrustiated with red oxide.

154 Metalliferous Minerals And Mining.

Half Tray down the cliff the lode expanded, and believing that it would increase in width downwards, Mr. Whitney recommended the opening of the lode at as low a point as possible. The dris at the base of the cliff was cleaned away, and the vein traced into the amygdaloid below. A level was driven, and at a distance of 70 feet the first mass of copper was strack, and the productive character of the lodes in the strata below the crystalline trap or greenstone proved. The direction of the lode is N. 27" W., and it underlies to degrees to the east. Its average width is 15 to iS inches, but it widens out in places to 3 or 4 feet Its metallic minerals are exclusively native copper and native silver.

The silver occurs in spots and patches, as if it were soldered in the copper. It is most abundant in the lodes at the points of contact between two dissimilar beds of rock.

The copper is divided : ist, into masses, often weighing many tons ; and, into panel work, consisting of lumps weighing several pounds ; and, 3id, into stamp work, consisting of grains of cover. When a large sheet of copper occurs in the vein, the rode is removed on one side of it, a small tunnel is driven on the other side, which is ehaiged with powder up to lacwt, and the lode blown down. In this way great masses of copper, weighing 60 or 70 tons, are blown down. These are of a tabular shape. They are broken or cut by chisel and hammer in the miiie into sizes convenient for removal, and further broken on the surface so as to be suiirio. 6a,— Shttiok of able for shipment. The mines of the Isle cimmMouNT*!' Royal are very similar to those just described. BrmuCTLu™ Ontonagon the metal seems more DDUD widely dispersed throughout the rock. It oc- FosiTs. curs in beds between the traps and sandstones,

"pifmut dep™!. and in seams and layers parallel with the bedding of the rocks, as shown in fig. 62. s, lu otiaic . ]5Q ju yg vcius, whose direction coincides with that of the strata, but which dip at a different aile. In

Copper Mines Of Canada. 155

one of these lodes at the Minnesota Mine, a mass of copper, weighing six tons, had been lifted from its bed and hammered all over by the Indians.

In the Portage Lake district there are not many regular veins, but the native metal is distributed in small masses, lumps, and grains, through regular metalliferous beds which differ little in other respects from the adjacent rocks. The most productive mine of this region at the present time is the Calumet and Hecla, which produces 900 tons of ingot copper monthly, or 10,800 tons a year. Besides this mine there is the Quincey, with a yearly production of 1,800 tons, of 80 per cent, value. The Osceola producing the same amount The Central Mine, which produces the greatest quantity, and largest masses of native copper in the district Its production of ingot copper is 1,200 tons a year. The Cliff Mine, which I have described, and some of the other old mines have fallen off in value, but it is hoped that explorations now in progress will revive them. The total present yearly production of the region may be taken at 15,000 tons.

Canada. — In Canada, on the north shore of Lake Superior, copper mines have been worked with varying success in similar deposits to those just described on the south shore, except that the amygdaloidal trap (5 of fig. 59, and 8 of fig. 60) has given place to a compact quartzose sandstone, which passes into a jasper conglomerate. A lode worked near Prince's Bay, having a course N. 32® W., was mainly composed of talc, heavy spar, and quartz. It was about 12 feet wide, and contained yellow sulphide and variegated ores. So far the mines on the north of the lake have not been as successfully worked as could have been desired.

Chapter Xix.

COPPER— continued.

Western North America — Colorado, Montana, Nevada, and Arizonar— Wyoming — Cuba — Jamaica — South America — Venezuela and Chili — Australasia — North and South Australia — York Peninsula — Flinders Range — Victoria — New South Wales — Japan — Inferences, and Concluding Remarks.

Western North America. — Copper deposits exist in Western Colorado, Montana, and in Arizona. The remoteness of the localities from railway communication, and the eager concentration of mining enterprise upon gold and silver ores, has hitherto prevented most of these deposits from being worked. During the last two or three years, however, the copper mines of Clifton and Santa Rita, in Arizona, have been rising into importance. These deposits occur as contact beds in the strata of the Yankee and Arizona range of hills, which, resting on a base of granite, consist of quartzite, slaty and homblendic rocks, with intercalated limestone, the whole being highly inclined The deposits occur between the quartzose homblendic rocks and the limestone. They are from ten to fifty feet thick, and consist of nearly pure red oxide of copper, which carries from lo to 50 ounces of silver. Small bunches of copper pyrites and copper glance have been found in depth. At the Longfellow Mine the deposit has been worked to a depth of 230 feet, and at the Gleason to 90 feet, without any diminution in the quantity and quality of the ores.

In Montana the Buttes vein, discovered three years ago, is an important deposit : 1,000 tons of ore 35 per cent, and con-

Enpneerin and Jmuing Journal of New Yorky January 1878, p. 53.

Copper In Cuba. 157

taining 15 ounces of silver to the ton, were raised from it in 1877. The lode occurs in strata of apparently the same age as those of Arizona, and the lodes are productive in homblendic and quartzoze slates above granite. The ores are oxides near the surface, with copper glance below, with small quantities of carbonates.

In the Ewing district, south of Wyoming, and on the line from Colorado to Utah, deposits, consisting chiefly of oxides of copper, occur in contact deposits from 3 to 50 feet thick. There appear to be three principal courses of ore, inclining with the strata at a high angle, and traceable along the surface for thousands of feet. Near the surface the ore occurs in sheets of from 2 to 8 inches wide, very free from earthy matter.' Samples assayed have shown silver as much as 50 ounces to the ton. The deposits lie between beds of slate and limestone.

Farther north, in the Upper Snake River Valley, are the Peacock and Monument Mines, where the deposits of copper are reported to be the most extensive on the Continent There is no doubt that similar deposits will be found, at the same stratigraphical horizons, all the way from the extreme north, southwards through the States named, and those lying to the south. The total yield of copper from the mines west of the Missouri river for the year 1877 amounted in value to about 200,000/., or say 15,000 tons.

Cuba. — As we pass southward we may notice briefly that copper mines were formerly extensively worked in this island. The deposits consisted of beds and masses that lay in the midst of greenstone and serpentine rocks, with their interstratified slates. The ores were the yellow sulphides mixed with iron ores. Near the surface the copper ores were oxidised, and in this portion of the deposits masses of native copper were found. The production of copper in Cuba was, in 1853, 2,200 tons. Similar deposits have been found in Jamaica, where there are also rodeo in which mines have been opened.

Is8 Metalliferous Minerals And Mining.

South America.

Venezuela.— Gaining the southern continent we find the mineral resources of this Republic rising into importance. One mine, the New Quebrada, shipped in 1877 4,446 tons of copper ore, of the percentage of iif, and for the first four months of 1878 2,400 tons of 15 per cent In Peru copper is largely mixed with silver, and both metals occur in veins, and also in beds and segregated deposits. Near Colcamba a segregated mass occurs in a variety of granitic rock.

Chili. — This Republic is the representative copper-producing country of South America, and one of the largest copper-yielding countries of die world Its yearly production of fine copper, for the ten years ending 1866, was 39,433 tons, W E

Fic 6).— Sbction of Copper Deposits near Copiapo, Chili.

a, Veta ; b, Guia ; Manto :— copper deposits, dd, Quartxoce and homUendic

rocks and slates.

and for the ten years ending 1876, 43,055 tons. The quantity raised in 1876 was 50,740 tons.

The deposits lie in the mountain range of the Andes, firom opposite Copiapo to Valparaiso. The strata in which they occur are foliated quartz and homblendic rocks with felspar ; occasionally there is calcareous spar, when the rocks become softer. There are both lodes and irregularly stratified deposits, and both often run roughly along the dip of the beds, which is fi-om to 55® W. The lodes ramify into the adjacent strata, as shown in fig. 63, which represents a deposit near

See Kenwood's Metalliferous Deposits,

Copper Mines Of Chili. I $9

Copiapo. The names of the different deposits are those by which they are locally known.

The lodes are charged with quartz, hornblende, felspar, and carbonate of lime. When they are very wide they contain great masses of quartz. In the upper portion these substances are mixed with iron ore. A lode at Punitaque was worked successfully for iron to a depth of loo yards, and then its metallic contents changed suddenly to copper. Lumps of native copper occur in the midst of the earthy brown ore at the top, which are coated with red oxide, and earthy black carbonate, with which a little gold is associated The ores change to sulphide in depth. The lodes widen out to 1 2 or 15 feet, but are often richest when not so wide. They are usually poorest when the rock becomes calcareous. The average quality of the ores from 1848 to 1853 was 18 per cent of copper. Until of late years ores under 10 per cent, did not pay to work, but through improved machinery and appliances, ores of 5 per cent and upwards are now profitably worked. Similar strata in the eastern half of South America are cupriferous; the production of Brazil for 1875 being estimated at 800 tons, and that of Buenos Ayres at the same quantity, of copper. In the latter coimtiy half the population are said to be engaged in mining.

We cross the Pacific Ocean, and notice lastly the copper deposits of Australaa.

Australasia. — The production of copper on this continent for 1876 stood as follows :

Australia North and South. — 3,276 tons, of the value of 249,978/., or over 75/. per ton.

New South Wales. — 5,225 tons of ore, of the value of 58,271/.

Victoria, — 37 tons.

The production of Australia was only half in 1876 what it was in the previous year.

Deposits of copper are found at various places, and the number will doubtless increase in the mountainous ranges, from Cape York on the north to the Australian Alps in Victoria on the south. The chief deposits hitherto worked are in the

l60 METALLIFEROUS MINERALS AND MINING.

Flinders range of hills, that run northward from near Melbourne, northwards in South Australia ; the two great copperproducing regions being those of York Peninsula and the Flinders Range.

The strata of the latter hills are the same as those of the general section of Victoria, the central ridge being the granite.

The copper ores occur in the overlying schistose, homblendic, and quartzoze rocks. They are found together with gold in places along the range for some hundreds of miles. The principal mines are the Blinman, Nuccaleena, Yudanamutana, and Sliding Rock. The ore seems to occur in irregular beds and lenticular-shaped masses that lie in the hollow of the rocks near the surface, the covering, if there ever were any, having been swept away. There are also irregular ramifications of veins. The Burra Burra Mine, situated about loo mDes due N. of Adelaide, has been of such conmiercial importance that it will form a good example of the ways in which copper ores occur.

Overlying the ancient slaty rocks, but unconformable to them, is a tufaceous limestone that fills up the depressions on the surface and runs down into the cracks and crevices of the underlying rocks. On some hills this tufa is two or three feet thick — in other places so thin as merely to give to the slaty rocks the appearance of having been used in buildings, and having thus acquired a coating of mortar. In fact, this limestone very much resembles old mortar, both in consistence and appearance. When accumulated to any thickness, large fragments of the underlying rocks are imbedded in the limestone. Organic remains have not been observed in the limestone of this district, but this does not prove that there are none, and a further examination of it may reveal some.

In a depression on the eastern slope of a hill so covered with limestone the Burra Burra Mine is situated. This depression is somewhat triangular in shape — the base of the triangle near to, and parallel to, the ridge of the hill ; the other sides much shorter, curved, and terminating below in a rocky creek, by which the waters of the mine are conveyed to the main creek. This depression is about half a mile long, and

BURRA BURRA COPPER MINE. l6l

300 yards wide in its broadest part, and is entirely covered with shafls and machinery for the raising of the ore, and crushing it, and two powerful steam engines for pumping the water from the workings.

In the deeper levels regular lodes are met with, running north and south, and containing very rich ore of malachite, red oxide, and grey sulphuret of copper ; but above the 30 fathom level there is no appearance of lodes, the ores (malachite and blue carbonate) being deposited with the greatest irregularity in the soil, the limestone, and the harder rocks. These last mentioned ores are of great beauty. The blue carbonate often occurs in round nodules, with crystals of the greatest regularity projecting from the surface. There can, I think, be no doubt but that the malachite is an aqueous deposit It is found in the form of stalactite, of slabs incrusting fissius, and of irregular-shaped hollow masses which have been deposited in cavities of the rock.

The Blinman Mine may be taken as another example. There is a mass of calcareous sandstone, which in depth becomes silicious. This sandstone is interspersed throughout with specks, patches, and strings of copper. It is also traversed by numerous veins containing copper ore, which coalesce, diverge, and form floors of ore 6 to 3 inches in width. The ore in the silicious sandstone consists of chrysocolla, malachite, and red oxide; but when, at a depth of about 250 feet, the sandstone becomes more silicious, the ore changes to a high quality copper pyrites. The ore is mixed with much iron. Its quality varies from 10 to 50 per cent, and it contains lumps of native copper assaying as much as 80 per cent

An important lode or deposit of copper is found in dioritic rocks on the Thomson river, about five mDes south of Stringer's Creek. This deposit is described as 30 feet wide, and consists chiefly of pyrites, with some carbonates and sulphurets. These lie in ferruginous quartz. Its direction is N. 15® W., and its underlie is only 20 from the horizon, and it is possible that it is after all a mineralised bed, or series of beds, like others we have noticed.

M

1 62 Metalliferous Minerals And Mining.

In New South Wales the ore raised is chiefly a sulphide, which occurs in lodes, the surface portion of which are filled with gossan. A lode worked at the Snowball Mine, between Gundagar and Adelong, is 8 feet thick, and is traceable on the sur&ce by the gossan for i,ooo feet. The ore stuff of this lode consists of various qualities of poor yellow oxide, assays giving per cent, yellow oxide with little steel grains 19J per . cent., black-coated yellow oxide 22 per cent, and blue and green carbonates 22| per cent

Japan.* — We may complete this journey round the world by observing that there are numerous copper-bearing lodes in Japan. The production is estimated at 3,000 tons yearly, and the number of mines is over 200. The most important mines are worked in the northern part of Nippon, in the province of Rikuchu, and in the island of Shikoku. The common ore is copper pyrites, but the variegated and grey copper ores are also found, native copper and the black oxide being rarely met with. The ores occur associated with iron pyrites and galena in quartz clay and fragments of the adjoining rock, that altogether fill nearly perpendicular lodes that traverse fine-grained porphyritic greenstone and altered slate rocks. The lodes vary from a few inches to three feet wide, one foot being the average. They have a general east and west direction, and are most productive in the porphyritic greenstone, having a tendency to thin out in the slaty rock. Lead is most abundant in the lodes running due east and west

In the province of lyo, at the Besohi Mine, there is a stratified deposit, consisting of massive copper and iron pyrites, with small quantities of quartz; this mineralised bed is from i to 10 feet thick, and occurs in the midst of clay slate, mica, schist, gneissic and quartzose rocks, which range NW. and S£., dipping at to NE. The bed has been worked a length of about 2,400 feet, and to a depth of 1,400 feet A similar deposit is worked at the Tanokuchi Mine, in the province of Tosa, at the junction of clay slate and diorite.

Godfrey, 'Geology of Japan,' Quarterly Geological Society, August 187S.

General Inferences. 1 63

Reviewing the foregoing description of the copper deposits of the worldj, it will be seen that, with trifling exceptions, they lie in three well-deflned stratigraphical zones. First, near the summit of the Lower Cambrian strata, just underneath the Lingula flags; secondly, near the base of the Carboniferous limestone; and, thirdly, in the sandstones of the Upper Permian and lower half of the Triassic strata ; the exceptions being the deposits of the Banat, of whose precise age we are doubtful, not knowing whether they belong most to the older eruptive rocks or to the newer Jurassic strata, and also the deposits of the Mouzia Pass in Algiers, concerning which we need more specific information. The largest and most successful copper mines in the world are worked in the deposits on the first or lowest zone.

It will also have been observed how universally loosegrained dioritic, homblendic, and felspathic rocks, with masses of loose drusy quartz, are associated with productive copper beds, and how seldom the mineral is found in workable form in simple day slate, or in massive compact quartzites or greenstone. In Norway and Sweden important lodes traverse gneissic rocks of average texture, the coarse and fine compact varieties of the rock being unproductive of copper ores. Further, it will be seen how the mineral, which was originally spread throughout a bed or series of beds, is gathered in a concentrated form in the cracks by which the strata have subsequently intersected; and, finally, it will have been noticed how, when such cracks run up into the overlying Arenig and Llandeilo beds, copper ores become more scarce as they ascend, as in the lodes of Carnarvonshire.

Chapter Xx.

Tin.

General Description — Modes of Occarrence — Alluvial Mining in Banca — In the Malay Peninsula — Tin Ore Deposits of Bohemia and Saxony — France and Sweden.

It is difficult to overestimate the value of this metal in the ordinary uses of life. To Britons it has especial interest from its ancient historical associations, carrying us back as it does in thought to the time between four and five hundred years before the Christian era, when traders from the East visited. the ancient Comubia, as Cornwall, from its horn shape, was called, to purchase tin of the natives. The metal is white in colour, malleable, but less so than copper, and is capable of receiving a high polisL

It is an unsettled point whether tin occurs in nature in a native form. It is reported as being found native as grains in the gold washings of the Ural, but some authors question the fact. Its ores are :

Cassiterite {Tin Ore, Oxide of Tin). — Hardness 6 to 7 ; gravity, 6*8 to 7 ; chemical composition : tin, 78*38, oxygen, 2 1 '62, but one or other of these elements is sometimes displaced by iron, manganese, tantalic acid, or silica. Colour white, but usually grey, and sometimes red, yellow, brown, and black, with a resinous, semi-metallic lustre. This ore has a variety named stannite, which has only 36*5 of tin oxide, with alumina and silica.

Tin Pyrites {Sulphide of Tin), — A rare ore, called in Cornwall, where alone it is said to be found, bell metal. Chemical composition : tin, 27, sulphui, 30, copper, 30, iron, 13.

Tin Deposits Of Banca. 1 65

In workable quantities it is iar less universally distributed, geographically, than the metals we have already considered, and hence the localities we shall have to notice will be very much fewer. Like gold it occurs both in rocks and also in alluvial deposits fonned by the wearing down of its containing strata. We will begin our notice of its distribution, and the modes of its occurrence in nature, in the far East

Banca.' — Tin is found to a limited extent in China, and in several of the islands of the Malay Archipelago, but it is worked to the greatest extent in the island of Banca, in the superficial drift of which tin was discovered in the year 1710. So fer the tin has been derived exclusively from these deposits, and the position in which it is found is shown in fig. 64.

. whin, and black

L'nderlyinc . iranil*. i, nod iiieuiiKir|)haKd tluu

The mining, or excavation, is of the simplest kind, and the manner of working will be described further on.

The tin ore is accompanied with fragments of the rock from which it was originally derived. This is granite, with a large admixture of schorl and sandstone. The alluvial tin is very pure, as the following analysis will show :

Tin 99961

Iron 0O'0i9

Lead 00-014

Copper 00-006

Both in Banca and on the island of Billiton the alluvial tin ' Bangia Bitchrtaen in Jieislogm, door P. Vin Diest, Mija-IngcDienr, 1865. (Engliih Tranilation by Dr. C. Le Neve Foster, Truro, 1B67.)

l66 METALLIFEROUS MINERALS AND MINlNt

has been traced to its source in the parent rocks forming the hilly country. The central rock is granite, covered by quartzites, altered sandstones, and slaty rocks. Quartz veins, containing mica, also traverse the granite and the immediately overlying tocks, and these contain varying proportions of tin, wolfram, and manganese. Large lumps of tin ore, averaging 40 per cent, also occm:, weighing from rootoi4olbs. The altered sandstone, just above the granite, is the most productive rock, and it is traversed in all directions by thin veins of tourmaUne, and of clay containing tourmaline. Tin occurs in the granite, and in the locks overlying it, over a large extent of Northern Banca. It occurs in small veins and bunches in the joints and along the planes of bedding. Hitherto no profitable tin mining in the solid rock has been made in the island. In the Malayan

Porphyty Gy GnoiM Fotphyiy

Fig. fis.— Section or Strata with Tin One. ZtNWALO.

Peninsula, tin diggings have been worked by the Chinese since the year 1793. The mines are swampy flats at the base of the hills. The ore seems to follow depressions in the drift for several miles in length, and these are known as streams of ore. The tin derived from this eastern region is known in commerce as Banca," 'Straits,' and 'BiUilon.' The production in 1876, according to the sales in Batavia, was 17,683 tons.

Austria. — little ore has been found in the districts of Penonta and Romilo, in the provinces of Orense and Pondevedra, in Gallicia. The ore occurs near the junction of granite with micaceous and homblendic slates.

Bohemia. — The great deposits of tin lie in the Erzgebirge range of mountains, whose geological structure I have

Tin Stockwerk Of Altenberg. 167

already described One of these, the Zmwald,' id partly in Bohemia.

Fig. 65 is a diagram section through the rocks in which this deposit lies.

The granite, 1, is overlaid on all sides by porphyriticiock, 2. In the granite are Toughty bedded layers, 333, consisting of quartz, mica, and oxide of tin, mixed with other minerals. These layers seem to convene towards the centre of the mass,

Fig. 66.— Sbctiom or Tin STOCKwuot, ALTaiiutc.

and in places, as at a, the mass of the rock is richly imprnated with tin ore.

Germany ; Saxony. — On the Saxon side of the Erebirge, or near the boundary between the two countries, arc other important tin slockwerks, two of which I will describe.

Fig. 66 is a section through the strata, in which the stockwerk of Altenberg ' is worked, i is a mass of poiphyriric granite, in which the crystals of felspar are very lae. 3 a mass of fine porphyridc rock, of a dark grey colour, passing in places to a reddish grey, and more rarely into a clear grey colour. The structure is not the same throughout, quartz being present in places. The mass is about 400 yards long by 300

' Wdssenbach, Merkwirdigt Gattgvtrkaltnini ; D'AnbitMm de Voititu, Traiti dt CUpieiit.

l68 METALLIFEROUS MINERALS AND MINING.

yards wide. 3 is a mass of syenidc porphyry, varying in colour from a light to a brown red, which contains numerous crystals of hornblende, and in places groups of crystals and grains of quartz. 4 is a variety of porphyry that approaches more nearly in composition to the central mass 2.

The whole of these beds are traversed by a network of fine flexuous veins, which vary from one to several feet in width ; and these are cut nearly vertically through by a larger and more recent fissure a (fig. 67), which is partly filled with the tires of the enclosing strata set in a matrix of ferruginous clay.

The network of veins are also filled in like manner, and all, through their course in the rock 2, are more or less charged with tin. Those that have a direct east and west direction are richest The same is true of the points of intersection. The

Fic. 6;.— Tin Stockhbic op Gmx: Section THBaucH it.

tin also penetrates the adjoining rock to a distance of several feet Indeed, the whole mass 2 is impregnated with tin, especially where quartz prevails. This is also true of the rock 4, and to a less extent of the rock 3.

The lodes are productive in the rock 2, but lose theii tin as they enter the porphyritic granite i, on the one side, and the syenitic rock 3 on the other. They regain their metallic contents to some dee in the rock 4, in the parts where quartz enters into its composition.

Another important tin stockwerk of the Erzgebirge is that of Geyer.' It lies on a circular truncated mass of fine-grained ' D'AubissoD de Voisins, Traisidi Ghgnom.

Tin Stockwerk Of Gever. 169

micaceous granite, i, fig. 67, whicK is covered on all sides by a gneissic rock, 3. The granite graduates into the gneiss, and the junction fonns a circular belt of stanniferous rock, z, which forms the stockwerk.

This belt, z, forms a granite different from the centre mass, i. The quartz and felspar are formed of fragments from two to six inches long, and from a quarter of an inch to two inches thick. Red felspar predominates. The quartz is splintery, crystalline, and compact, and sometimes occupies large spaces. Mica is also present in nests and fragments.

The whole mass is traversed by vertical veins and horizontal layers charged with tin. The veins are of variable width, and the thiimest do not extend far, rarely passing beyond the granite. The strongest are most regular and persistent, and pass into the granite, and also into the surrounding gneiss. As a matter of observation it is found that the true east and west veins are richest in

tin, and the points of _vims ih er OitRs suowon:

the intersection of the c-.tbai. v.ih> ad rock oh uthu veins are productive

of the mineral. The granite itself is impregnated with tin, but contains the least where the veins are less fiquent.

In quarrying the mass the veins show for the most part a parallel vertical appearance. Their intimate structure is shown more minutely in fig, 68. The centre of the vein is mostly

I70 Metalliferous Minerals And Mining

filled with quartz, and fragments of the adjoining rock with tin ore. The dark shading shows how the rock has become partly decomposed and recrystallised for some distance on either side, and this portion adjacent to the vein is interspersed with grains of ore. The veins in the figure lie about fifteen inches apart. The deposit has been worked to a depth of between 400 and 500 feet.

The annual production of tin in Austria and Germany is estimated at not more than 200 tons; but the deposits have more scientific than commercial importance.

France. — There are the traces of ancient tin mines and detrital tin works in the neighbourhood of Auvergne, in the southern part of Central France.* Attempts have been recently made to revive this branch of mining industry in the region. These so far have been unsuccessful, but a brief notice of the district will be useful for comparison. There are great masses of granite of two kinds, the oldest of which has its mica all black, the newest has both black and white mica. Against these erupted granites lie, first crystalline schists, next gneiss, and then mica slate. The whole series with the granites is traversed by veins or lodes. Tin ore, when found, usually lies on the sides of the veins, and the granite is oflen, for some distance from the crack, decomposed, the felspar having given place to clay. With the tin ore in the lodes there are associated wolfram, mispickel, native copper, arseniate of iron, fluorspar, sulphate of barytes, more rarely phosphate of lime, and more rarely still grains of gold. Detrital tin has been worked in the gravels overlying the granites.

Sweden. — This country produces about 200 tons of tin ore yearly, but we lack information concerning the character of the deposits, and pass at once to consider the tin mines and deposits of the British Isles.

Ann, da Mines, srie, liv. — Mallard, 'Note sur les Gisements da Limousin et de la Marche.'

Of '0

lES ON THE

Chapter Xxi

TIN-<onHnued.

Tin in the British Isles — Cornwall — Importance and Antiquity of the Industry — Brief History of Tin Mining in the County — The Great Flat Lode — Cligga Point— Remarks on the Depths of Mines, and on the particular Structure of the Tin Lodes of Cornwall.

The British Isles : CornwalL-The raising of tin ore formed one of the earliest of British industries, and helped to fomi the foundation of the commercial character of the country. Diodorus Siculus, 60 b.c, describes the tin trade of these islands ; and St Michael's Mount, Cornwall, is supposed to be the market where it was carried on. The industry belongs to Cornwall, and to a very little extent to the contiguous part of Devon. Up to the eleventh century it is probable that the whole of the tin raised was derived from ' stream works ' and the washing of stanniferous sands and days. About the date named lode mining for tin is believed to have been begun. The tin mines of Cornwall were, in the reign of King John, farmed for 100 marks per annum, which amoimt was increased in the next reign, when we find the Jews engaged in them, from which circumstance it is probable that the industry was then of a lucrative nature. .

The tinners petitioned Edmund, Earl of Cornwall, by the Lords of Blackmore, for a charter that should define their rights. This was granted, and confirmed by Edward I., in the thirty-third year of his reign. This charter conveyed the right of holding a court — the Stannaries Court — for the consideration and settlement of all disputes and matters relative to tin mining. This tinners' parliament was allowed to be convoked at discretion,

Carew, Suruty of Cornwall p. 17.

1/2 Metalliferous Minerals And Mining.

and the charter gave the right to each tinner to sell his own tin, unless the king wished to buy ; also the right of cutting turf on the king's lands for smelting. For these privileges the tinners were to pay a duty of one halfpenny for every pound of tin manufactured. To secure the payment of the duty, all tin was to be brought to certain towns at Midsummer and Michaelmas to be weighed, and kept until the duty was paid

In the reign of Henry VII. his son Arthur made some obnoxious regulations for the Stannaries, which the tinners refused to obey, and which provoked them to breaches of the law. On the death of his son, the king made this conduct an excuse for cancelling the charter, and for taking the mines into his own hands.

Not finding mining profitable, he gave the mines back to the tinners, with the further important concession that no law relating to the tinners should be enacted without the consent of twenty-four gentlemen — tinners — six to be chosen by a mayor and council in each of the four Stannary divisions.

In the time of Elizabeth the production was about 700 tons a year, and the price from 45/. to 50/. per ton. In the reign of James I. the make of block tin in Cornwall amounted to about 1,500 tons a year. The production was about the same in the time of George I. About the year 1742 it had increased to 2,000 tons, and from 1750 to 1778, the production was estimated at 3,000 tons a year.

The total production of tin ore in Cornwall and part of Devon for the year 1877 was 13,995 tons 10 cwt., of the value

The production for the previous year was 14,004 tons

17 cwt. oqrs. 13 lbs., of the value of 700,514/. 5. 2d. It will thus be seen that, while the production in 1876 was only 355 tons less than the year before, the value was, owing to depreciation in price, less by 124,910/.

The ore was derived from 183 mines, inclusive of 27 stream works. Of this number, 174 mines proper were situated in Cornwall, and 9 in Devon. Of the 174 Cornish mines, 100,

William Pryce, Mineralogia Cornubiensis,

Great Flat Lode Of Redruth. 1 73

producing 10,501 tons of ore, were situated in the western half of the county. The mineral results thus agree with the general description of the characteristic mineral features of the county given in the description of its copper deposits. In 1879 the production of tin ore (black tin) was 14,280 tons 8 cwt.

The tin deposits of Cornwall have been described by many able observers,* and all the works mentioned in the note below are full of information concerning them.

One of the latest observers is Dr. Clement Le Neve Foster, F.G.S., one of H.M.'s Inspectors of Mines. In the course of his official duties, Dr. Foster has had many opportunities of studying the characteristics of and acquiring inf6nation concerning the lodes of Cornwall. The observation of these characteristics has accorded with his tastes, and he has brought to the work the ability resulting from culture and practice. I do not think, therefore, that I can do better than avail myself of his generous permission to use his descriptions and illustrations of the tin lodes of Cornwall which have appeared in several of his communications to learned societies.

Let us begin by noticing the structure and character of the Great Flat Lode south of Redruth and Camborne.

This lode extends from the Perseverance Mine on the east to South Tolcame on the west, and runs along the south side of the granite mass of Cam Brea.

Fig. 69, prepared by Dr. Foster* and Mr. Thomas B. Provis, affords a plan of the mines wrought upon it, and a section of their workings.

The dip of the lode is much flatter about 30 to 50° south than the average dip of the tin lodes of Cornwall, which is about from the horizon. It also varies in width, structure, and character, as the following illustrations from observations by Dr. Foster will show :

Pryce, Mineralogia ComubienHs ; De la Beche, Report on Devon and Cornwall; Fox, On Mineral Veins; Henwood, Came, and others, in Transactions of the Royal Geological Society of Cornwall ; Moissenet, On the Lodes of Cornwall; Salmon, in Mining and Smelting Magaane &c.

Quarterly Journal of the Geological Society Aagust 1878.

174 Metalliferous Minerals And Mining.

Fig. 70 is a section of the lode at Wheal Uny Mine, in a stope above the 110 fathoms level

A is the leader, or original crack, from 3 to 10 inches wide, which is filled by fragments of chloride slate, cemented by quartz and iron pyrites, b b is a variable thickness of tine-

FlO. J0.-SBCT10N AT WuUL UmV, AIOVI THB Im FATKOUS

grained or compaot schorl rock, with strings and spots of quartz and tin ore ; h is a clay vein, containing a Htde quartz and iron pyrites ; c is similar to b, and contains 4 inches of tinstone under the leader i. e and e aie capels consisting of compact schorl

rock, the upper one showing the material arranged in layers ; c granite ; y killas, or slaty rock. The lode at this point lay, it will be seen, between the granite below and the killas above, into each of which it gradually passed without any dividing wall from the central leader or crack. Fig. 71 represents the structure

The Flat Lode At Condorrow. I7S

of the lode at West Wheal Basset Mine, at a depth of 104 fathoms.

A is llie leader, 3 to 3 inches thick, filled vith fragments of capel ; B B consists of stanniferous schorl rock of - bluish grey colour, passing into cc, an unproductive schorl rock (capel), A"— fool

with large grains of quartz set in a black matrix, a kind of rock always unproductive. The combined thickness of B and c above the leader is 9 feet, and 6 feet belov it The unpro-

ductive rock passes gradually into the granite c G, which here encloses the lode on both sides. Another variation in the structure of the same lode is seen at South Condurrow Mine, as represented in fig. 71.

A is the leader, filled with clay, much quartz, and oxide of iron,

176 Metalliferous Minerals And Mining.

and fragments of the adjacent rock ; b is the tin-bearing rock, about 5 feet thick, consisting of compact stanniferous schorl rock, black and slaty in colour, traversed by numerous quartz veins of all sizes up to 2 or 3 inches wide, and little cross veins besides vertical joints filled with iron pyrites. This passes into c c, compact schorl rock (capel) ; with veins and spots of quartz, and little or no tin, it fades into the granite g g. At South Cam Brea, at a depth of 175 fathoms, the leader, which there was from 2 to 4 feet wide, was charged with copper ore. Here it lay between the granite below and killas above. In places, as at West Wheal Basset, the whole of the schorlaceous rock, capel included, is stanniferous, and expands to a width of about 50 feet. Fig. 73 shows another variation of the lode at South Condurrow.

The whole of the stanniferous portion of the lode is taken out, and the following figures will show the proportion of tin stuff and clean tin ore produced in 1876 by six of the mines on the lode :

Name of Mine

Tin stuff

Clean tin on

Tons

Tons

Wheal Uny

17,702

South Cam Brea

2,040

West Basset

29,144

West Wheal Frances

6,652

South Condurrow

Wheal Grenville

Total .

8,500

83,452

1,846

The clean tin ore was therefore about 2 J per cent, of the ore raised, and the lode altogether jrielded over one-eighth of the total quantity raised in Cornwall

We will next take a few illustrations of the structure of other tin lodes in the county.

Fig. 74 represents a plan of a pipe of ore at East Wheal Lovell Mine, near Redruth.

A B is the original crack or leader, from a quarter to half an inch thick, filled with quartz and ferruginous clay; c c shows the

Tin Ore In Slates Of St. Colomb.

tinny mass that gradually passes into the granite dd. The granite D contains large crystals of oithodasc. The dnny mass c c is made up of a mixture of quartz, mica, gilbeitite, fluorspar, iron and copper pyrites, and i"-!!**!-

cassette, or tinstone. Sometimes the tin ore inclines more to one side and again to Hie other. This pipe of ore varies in length from i a to 36 feet, and in breadth from 9 to 13 feet It has been followed down from the 40-fathom level to the 1 10 as one continuous pipe. In places, when tin was selling at 80/. per ton, it was worth from 800/. to 1,000/. per fathom, and generally gave from 5 to 6 tons per cubic fathom.

The East Wheal Lovell lode occurs in granite, but the next illustration, fig. 75, shows the occurrence of tin ore along the lines of bedding of slates . at the Park of Mines, south of Sl Columb. The slates lie, however, in proximity to the great granitic mass north of St. AustelL

The slates dip at an angle of 70 degrees to the north, and

numerous lenticular masses 01 loviu. Hihm, rediuth. tin stone occur along the lines t™ lode. cc, Cnuwi impctciuud of bedding. There are also '"

thin veins of one to two inches, containing tinstone crossing these deposits. The bedded tinstones range from one to two inches thick, occasionally expanding to a thickness of one fooL

178 Metalliferous Minerals And Mining.

They nin about 7 fathoms fiom north to south, and about 10 fathoms down the dip. The tin ore is assodated with quaiti, school, and kaolin.

The granitic mass of Cligga Point will furnish us with a C irish equivalent of the stockwerk of Geyer. This mass is about 300 feet hi, and it is traversed by a great number of nearly parallel veins, as shoivn in fig. 76, which also affords a nice illustiation of lodes displaced by a fault.

The veins dip north at

angles from 65 to 80 degrees.

Fig. 77 gives a view of the in-

5 dmatestructureofoneof these

veins.

I r is a vein of quartz three inches wide, in which the ctystals starting from each wall sometimes meet in the middle, and some times leave a vugh or open cavity, containing, as does also the quartz, cassiterite, woUhun, mispickel,and schorl 3 3 is a band of dark rock — ' greisen ' — four inches wide on both sides of the quartz vein. This rock is quartz and mica, or granite without the felspar, and contains schorl, gitbertite, stone, Acicular crystals of schorl frequently fill up the cavities apparently left by the removal of orthockse. This rock graduates into the adjacent granitic rock 3 3. The width of the veins varies from half an inch to six inches wide, and they lie from a few inches and a few feet apart. It may here be observed generally that tin is sometimes in Cornwall mixed up with iron in the gossan overlying a copper lode, when it is considered by the miners a good sign for copper below. Whi mixed up wltli copper in a lode, tin usually pre-

Tin Veins Of Cligga Point. 1 79

vails on the upper side, although it is occasionally found under the copper. When so found the tin and copper are divided

Fm. ;&— Secdoh of Gbakiti, with Vums of Tib Qim, Cucca

Foiht, Oumwau.

from each other by parallel layers of quartz, clay, and other earthy minerals. When tin and copper occur in the same lode

Fn. n.— Ehlaigu) View of Vuki ih Ciuniti at Cugca Point.

on opposite sides an increase of one ore on one side is usually accompanied by an increase of the other on the other side. If

iSO METALLIFEROUS MINERALS AND MINING.

the ore on the foot wall diminishes it is considered an unfavourable sign ; if it increases, it augura welL When lodes traverse beds at right angles to the dip of the latter the ore masses have a shoot or inclination corresponding to die dip of the beds.

A hard black gossan yields some tin, but the mineral is not easily worked to profit in it, nor does it often occur in a satisfactory state in a peachy lode. In pryany lodes tin often occurs in grains of fine quality. These lodes are really detritat deposits, cracks into which materials have been washed : hence the similarity of the ore to stream tin. The best lode is a scovan, BO called because it is composed almost exclusively of tin ore. The rocks in which tin lodes are most profitable are.

fio. jg.— Sbction of Lodi at Olh Hiwa> Uma, Corhwali,

as we nave seen, the half-decomposed schorlaceous granite, and the immediately overlying slaty rocks or killas where these are of a brown or reddish colour.

The depth at which tb may be profitably worked depends chiefly upon the nature and dip of the strata. It is worked to great depths in granitic rock of a favourable kind, and in killas where these dip at a great angle, and where they are overlaid with newer strata. Its stratigraphical place and profitable zone occurs below that of copper, but there is of course, as we have seen, a dovetailing of the two minerals vertically. Thus at Old Huel-Vi vian a tin and copper lode was wholly in granite ; the lode varied from 2 to 40 feet wide, contained large angular masses

OLD HEWAS MINE. l8l

of granite, with yellow copper ore and tin lying between them. It was crossed by eleven cross-courses in 170 fathoms, and the lode was most prolific near the points of intersection. We may take this lode as an example of many other mechanically formed lodes into which both metals were washed from their parent rocks at a date subsequent to that of the origin of most of the true tin lodes we have been considering. Old Hewas Mine gave a good example of richness at the point where the lode was crossed and broken by a cross-course. Fig. 78 is an illustration of this. Tin lodes often increase in productiveness also near their junction with elvan courses or felspathic dykes crossing them.

Chapter Xxil

TIN— continued.

Alluvial Tin Deposits of Cornwall — Tin in Bolivia, Queensland, New South Wales, Victoria, and Tasmania — General Deductions and Concluding Observations.

We may now pass on to notice the alluvial tin or stream tin deposits of Cornwall. These are of two kinds : first, natural deposits, in which detrital tin brought down from its parent rocks on the higher lands has settled down in river streams and valleys ; and, secondly, the deposits where fine tin ore escaping from the dressing-floors of mines has settled down in the bed or on the banks of a stream where conditions were favourable. It is with the former we have chiefly to do now.

In the year 1877 there were 27 stream tin works in Cornwall. Of these 18 were on the Red River, and 9 on the tributary that, running down from Cambrea and Tincroft, joins this river at Tehidy Mill. The amount of tin raised from this source in 1877 was 753 tons 4 cwt. 2 grs., or about one-fifteenth of the total amount raised in Cornwall and Devoa About 800 persons are employed at these stream tin works, whose combined earnings are given at 1,500/. per month*

Formerly alluvial tin works were spread over laige portions of the lowlying lands of Cornwall, along the estuaries of rivers, and on the seashore. The following selected sections will give some idea of the ground enveloping these tin deposits.

' Quoted by De la Beche, Report on the Geology of Cornwall and Devon,

Alluvial Tin Deposits. 1 83

Section of tin ground near the Par estuary, taken by Captain Barratt:

Feet Inches

1. River deposits 16

2. Irregular mass of mud, sand, day, and stones . 7 o

3. Old surface of mud, clay, and vetable matter . 8 o

4. Fine sand, with sea shells, and on the top rolled

pebbles ..40

5. Mud, clay, sand, woodnuts, and other vetable

matter 30

6. Tin ground resting upon an uneven surface of slate o 6 to 6 feet.

Section of the Camon stream works, taken by Mr. Henwood :

Feet Inches

1. Sand and mud, river wash 30

2. Silt and shells — three successive beds . . . o 10

3. Sand and shells, with a stream of firesh water . .20

4. Silt — three beds 12 o

5. Sand and shells 3 feet 10 inches to 4 o

6. Silt largely mixed with shells 12 o

7. Silt in some places containing stones . .18 feet to 22 o

8. Wood, moss, leaves, nuts, &c., a few oyster shells, with the

bones of deer and human remains . .16

9. Tin ground . . . varying from a few inches to 12 o

10. The shelf or rock of dirty white and pale blue slate

The bed 8 sometimes disappears when bed 7 rests immediately upon the tin ground. The latter consisted of rounded masses of tin ore, in places unmixed, and in others contained in a matrix of quartz and quartz and schorl associated with rounded pieces of slate, granite, and quartz.

Other sections show a similar succession of beds, and contain the vegetable bed immediately above the tin ground. The presence of this bed in this position shows the veiy recent date of the overlying driftal matter, and leads to the following theoretical inquiries. Was the detrital tin only deposited just before this recent vegetable deposit, or, as its rounded character would indicate, was it a vastly older deposit ? If the

1 84 Metalliferous Minerals And Mining.

latter, had it remained exposed on the surface for aes, or had it been covered with older drift of glacial times, which had been denuded before the deposition of the recent vegetable bed ? Probably the latter supposition is nearer the truth, in which case the tin deposit belongs to the age of those local preglacial drifts whose place is everywhere in the hollows of the solid rock, and which are in their turn covered usually by the lower boulder clay or some other member of the glacial series. Such inquiries have, however, more interest for the speculative than for the mining geologist, and I pass on.

No discovery of tin ore of any importance has hitherto been made in North America. In South America it has been mined to some extent in Bolivia ; but I now proceed to notice the recently discovered important deposits of the mineral in Australasia.

Queensland. — Beginning on the north with Queensland, the discovery of tin in this colony was reported by the Government in the year 1872.' The stanniferous country lies between the head waters of the Condamine River on the north, and the boundary of New South Wales on the south. It comprises an area of about 550 square miles, of which about onehalf has been proved ground sufficiently rich in ore to pay for working. The higher part of this region consists of an elevated granitic tableland, intersected by ranges of abrupt hills, some of which rise to the height of 3,000 feet above the sea. Several rivers have their rise in this elevated country, and force their way through deep narrow gorges to the open coimtry below. Among these are the Clarence, Condamine, Severn, and Macintyre. It is along the course of the River Severn, from near its source down to Ballandean, a distance of 140 miles, that the principal alluvial tin deposits are found. There are also 30 miles of rich tin ground along the tributaries of Pike's Creek.

The richest deposits lie in the stream bed, and on the flat ground of both banks of the Severn, and they extend to a distance varying from a few to one hundred yards on both sides.

' Gregory, *0n the Discovery of Tin in Queensland,* Quarterly JburfuU Geological Socieiyt voL xxix. p. i.

TIN DEPOSITS OF NEW SOUTH WALES. iSj

These two belts are broken across by rocky ridges, but tin ore has been largely accumulated in the hollows lying in and between these barriers. The quantity of tih ore contained in this river belt reaches as high as 30 tons to the chain in length, and its average yield is estimated at 10 tons per chain (22 yards).

Two principal tin lodes have been discovered in situ near Ballandale Head Station. The rock here is a coarse-grained granite, which soon disintegrates on exposure to the atmosphere. Mixed up with this granite are numerous bands of loosely aggregated granitoid rock, containing much mica, and traversed in all directions by bands and veins of quartz.

In these bands crystals of tin ore, cassUeritiy are abundant. They are generally found imbedded in and along the margin of the quartz veins and bands, and also occasionally in the midst of the mica, which, when such is the case, is invariably white in colour. The strike of these quartz veins and bands is N£. by SW. Other smaller veins have been discovered, but so fsur little or no attention has been paid to mining for tin in the solid rock. The quantity of stream tin raised in the year 1874 is given as 5,585 tons 6 cwt 3 qrs. and 9 lbs.

New South Wales.* — The same geological conditions are continued southward into this colony, near the northern boundary of which, Mr. D. Brown, of Sydney, claims to have first discovered tin ore among the stuff thrown out of an old saw pit. The discovery of tin ore in the colony was first brought into notice in this country by a communication made to the Geological Society in December 1871, by Mr. G. M. Stephen, F.G.S., of Sydney.

The ground on which Mr. Brown's discovery was made afterwards became the property of the Elsmore Tin Mining Co., and it will afford us the best illustration, perhaps, of the mineralogica] conditions in which the ore occurs. The land lies on the north-west side of the Macintyre River. It is intersected by a granitic range, 250 feet high and nearly two

Observations on some of the Recent Tin Ore Discoveries in New South Wales, by G. H. F. Ulrich, Quarterly Journal Gtohgkal Society vol. xxix. p. 5.

1 86 Metalliferous Minerals And Mining.

miles long. The granite is micaceous, and contains crystals of white orthoclase, which are often several inches long. More rarely the orthoclase is bluish grey in colour. This granite is traversed by quartz veins from four to five inches wide, in which, in fine druses, seams, and single crystals, tin ore occurs. The quartz of these veins gives place occasionally to a micaceous greisen-like rock.

Besides these quartz veins, the great mass of granite is traversed by dykes of softer granite, three-fourths of which consists of mica, and the remaining fourth of felspar, without much quartz. In these micaceous dykes, tin ore is plentifully dis. tributed in grains from the size of a pea downwards, and also in irregular veins several inches thick, and in nests and ramifications, which often yield lumps of nearly pure ore in all sizes up to 50 pounds in weight.

One of these dykes, of which there are at least six in the property, forms a regular breccia of mica and partly crystallised tin ore, cemented together by hydrous oxide of iron.

It is fi'om the disintegration of such dykes and stanniferous masses that the rich alluvial deposits of tin, that nese in the lowlying lands and along the banks of the streams, are derived, for with the tin ore in such deposits are found fi:agments and grains more or less worn of the original enclosing rocks. Thus far tin mining has been confined to alluvial workings, the particulars of which for the year 1876 are thus enumerated by the Mining Registrar

Locality

Number of miners

Or

Value

Tingha

Glen Innes Vegetable Creek Tenterfield Tumbanimba . ; . . Tenteifield Tin Ingots .

Total

Tons 2,300 1,000

69,000 30,000 90,261

40,3'J2

22,440

1,654

7,7o6i

252J13

Report of the Department of Mines New South Wales,

Tin Ores Of Victoria And Tasmania. 1 87

Victoria. — Proceeding south into the colony of Victoria, tin is found near the boundaries of the granitic masses of Beechworth and Berwick, in the county of Momington. The Beechworth mass of granite is fine grained and highly felspathic, but it contains portions highly micaceous, like the Saxon and Cornish greisen.' In these portions tin ore is found associated with stanniferous sand.

In the gravels and alluvial deposits surrounding these granitic masses tin ores are found, and they are often associated with gold. The pure ore firom Woolshed Creek contains 78 per cent, of tin and 22 per cent of oxygen. As sold the ore assays about 53 per cent, being mixed with titaniferous iron ore and other substances. In the desire of the mineis to obtain gold it is to be feared that tin ore has been much neglected. The exports of tin for the year 1877 oy 34 tons 9 cwt.

Tasmania. — Farther south, tin ore has more recently been discovered at Mount Bischoff, in the NW. portion of this island. Moimt Bischoif rises from the western side of the basaltic plateau of the Surrey Hills to a height of 2,500 feet above the sea. It is described as a porphyritic rock containing granules and crystals of quartz and felspar. It weathers white, and is honeycombed on the surface from the decay of pyrites, which are abundantly disseminated in it On its western and southern sides it is overlaid by metamorphic and contorted schists. Veins and strings of tin ore — oxide of tin — traverse the rock, and tin ore occurs in the joints.

There are also gossany outcrops of larger lodes, and irregular deposits of great extent in which are minute particles of tin stone. Larger lumps up to 400 and 500 lbs. weight of rich tin stones also occur.

From the disintegration and denudation of these rocks, tin ore fills the troughs and hollows of the mountain side : hence the hill has been called a mountain of tin ore. Similar

Brongh Smyth, GoU Fields, dfc, of Victoria. Gould, 'On a Recent Discovery of Tin Ore in Tasmania,* Quarterly Journal Geological Society , vol xxxi. p. 109.

1 88 Metalliferous Minerals And Mining.

discoveries have still more recently been made farther south, at Mount Heemskerk, on the west coast. The amount of tin exported in 1873 estimated at 7,000/. In 1877, the estimated value of the tin exported is stated at 380,000/.

In reviewing the foregoing description of the tin deposits of the world, we are impressed with the great uniformity of the geological and mineralogical conditions under which it occurs in si/u, as tliese have been described at widely different times by widely different observers.

Its home is in granite, which, imderlying, as it is seen to do in Banca, Germany, France, Britain, and Australia, the oldest known sedimentary rocks, belongs evidently to the Laurentian series, if not to an earlier primitive group.

It abounds most in granite of a peculiar type, from whose composition felspar is largely absent and mica largely present. Everywhere it is accompanied by schorlaceous conditions of the rock. Were these granitic dykes thrust through the older granite with their enclosed minerals ? or do they lie along the lines of ramifying cracks, up which vapours charged with stanniferous matter have come, dissolving the felspar and leaving its mineral burden of tin behind, just as we see has been the case in the stockwerk of Geyer, fig. 68, in the thin lodes of Cligga Point, Cornwall, figs. 70 and 71, and in the ore pipes of East Wheal Lovell, fig. 74 ?

Geologically, the correlation of the granites of Cornwall with the other tin-bearing granites of the world, fixes, I think, the age of the former, and confirms my inference, before stated, that the older and tin-bearing slates and metamorphic rocks of that county are nearer Cambrian than Devonian age.

;

Chapter Xxiil

Lead.

Native Ores of Lead — Lead Ores of Aastro-Hungary—Banat— Carinthian Alps — Bleibeiig — Germany — Erzgebirge — Hartz — Clausthal and Zeller— Nassau — Rhenish Provinces — Spain — Brief History— Andalusia — Sierra de Almagrera — Linares — Homachos — France — Pontgibaud — PouUaouen — Bretagne — Belgium.

Though of less money value, owing to its wider distribution in nature, this metal, whether used alone or in combination with other metals in the shape of alloys, is one of the most useful of all the metals. In colour it is of a bluish grey, it is easily fusible, it is soluble in nitric acid, and is very malleable. The chief forms in which it occurs in nature are the following: Native Lead. — Very rarely the metal occurs in this form, but it has been found native in the mines of Alston Moor, in meteoric iron in Chili, in lava in Madeira, in clay slate at Carthagena, and near Kenmare in Ireland. In this form its hardness is x*5,and its gravity 11*3 to xi'4.

SULPHURET, OR SULPHIDE OP LeaD. — GaLENA. — This is

the most plentiful ore of lead. Chemical composition : 86*55 lead, and 13*45 sulphur. It usually, however, contains, as we have seen, a little silver, with varying small proportions of copper, zinc, or antimony, when of course one or both of the chief constituents are displaced to some extent Gravity, 7*2 to 7*6.

In combination with other substances we have the following varieties of this ore :

Clausthaiitey mixed with selenium in varying proportions, and giving a horse-radish odour when fused. Hartz mountains.

I90 Metalliferous Minerals And Mining.

Cobaltic lead ore, mixed with arsenic, and with a trace of cobalt Hartz.

Cuproplumbite containing 24*5 per cent, of sulphide of copper. Chill

Dufreynoysite with a proportion of arsenic, of a dark steel grey colour. Dolomite of St. Gothard.

Tdluride of lead oli a tin-white colour, and cleavable. Altai Mountains.

Tellurium-Foliaied, — Chem. com. : 32*2 tellurium, lead 54*0, gold 9*0, with silver, copper, and sulphur. Transylvania.

Oxide of Lead. — Minium. — Red Lead of Commerce. — Chem. com.: 907 lead, 9-3 oxygen. Colour, red, streaked with yellow. Occurs in Yorkshire, Anglesea, and Siberia. Its variety is :

Plumbic Ochre,

Sulphate of Lead. — Anglesite. — Chem. com. : 737 of protoxide of lead, 26*3 sulphuric acid, with a little silver. Colour, white, to yellow, grey, and browa Occurs at most mines. Its variety is :

Cupreous Anglesite containing an admixture of copper of an azure blue colour, and possessing a perfect cleavage.

Carbonate of Lead. — Cerussite. — White Lead Ore. — Chem. com.: 83*6 protoxide of lead, and 16*4 carbonic acid. In colour ranging from white to black, fuses easily, and dissolves with effervescence in nitric acid. Its varieties are :

Dioxyliie Leadhillite and CcUedonite. These are distinguished by the presence in larger proportions of carbonic acid.

Phosphate OF Lead.— Pyromorphite. — Chem. com. : 897 phosphate, and 10*3 chromate of lead, varied with o to 9 arseniate of lead, o to 11 phosphate of lime, and o to i fluoride of calcium. A brown variety gave the following composition : 78*58 of oxide of lead, 1*65 of muriatic acid, and 1973 phosphoric acid. Usually of a greenish colour, and occurring in beautiful crystals. Its varieties are :

Hedyphane, containing some arsenic and 2 per cent of chlorine. Found in Sweden.

Mimdine containing also a proportion of arsenic Cornwall

Lead Mines Of Austro-Hungary. I9I

Chromate of Lead. — Crocoisite. — Chrome Yellow. — Chem. com. : protoxide of lead, 68*15 I chromic acid, 31*85. Colour, orange red to yellow. It has the following varieties :

Corneous iead containing some carbonic add, and occurring in white adamantine crystals. Derbyshire and Germany.

Mdanochroite containing only 23'64 of chromic acid, of a dark red colour. Siberia.

Mendipite containing 38*4 of chloride of lead and 61*6 of oxide of lead. Mendip Hills.

MolybdcUe — chem. com. : protoxide of lead, 64*42, molybdic acid, 34*25. Bleiberg.

Plumbo-resinite — contains protoxide of lead, 40*14, alumina,

3 7 'CO, and water, 18*8.

Senate of lead containing selenium, rarely found ; occurs

in small globules.

Tungstate of Uady — chem. com.: lead, 49, and tungstic acid,

5'.

Vanadiniie containing vanadium, and occurs in hexagonal

Omitting the mines of the Altai and Daouri mountains of Siberia, where lead ore is mined chiefly for the silver it contains, we will take as our easternmost starting-point, in our description of the chief lead ore deposits of the world, the mines of Austro- Hungary.

AusTRO-HuNGARY.* — We have already seen that lead ores are associated with the minerals forming the contact deposits of the Banat, and these deposits will not require further description. The same remark applies to the lead associated with the silver ores mined on the Bohemian side of the Erzgebirge ; but in the continuation southward of this mountain chain we find important mines worked at Przibam, and farther south still, near the village of Villach, near the NE. comer of the Tyrol, in the Carinthian Alps, are the lead mines of Bleiberg.

The deposits of Przibam lie between the upper surface of a greenstone rock and the overlying metamorphic schist, and thus form contact deposits. The matrix consists of quartz,

See Whitney's MttaUk WtaUh ; also Ann. <Us Mimts (4) 8 and (4) I.

192 Metalliferous Minerals And Mining.

brown spar, and heavy spar. The ore is galena, which is associated with antimony, blende, grey copper, iron pyrites, and silver ore. These deposits become profitably productive at a depth of about 300 feet Besides the contact deposits, there are also true veins, which traverse sandstones and conglomerates of apparendy the same age as those of our Shropshire and Cardiganshire lead mines. The number of veins of all sorts at this point is thirteen.

The mines that stretch along the valley of the Notsch, between Bleiberg and Kreuth, a distance of about fifteen miles, occur in a light grey limestone, which is traversed by veins and cavities filled with calcspar, in which occur irregular masses of galena associated with carbonate of lead, calamine, and blende. These have been followed down to a depth of about 1,500 feet The annual production of lead in Austro- Hungary is 7,000 tons.

Germany. — Passing by the mines of the Erzgebiige, which have already been described, we find that near Tamowitz, in Silesia, lead mining has been carried on for more than 300 years. A rich and curious deposit lies between the Muschelkalk and a dolomitic limestone. The deposit has been explored for a length of five miles and a breads of one mile. It is about 12 feet thick, and consists chiefly of red calamine, with a bed two or three inches thick of galena in its upper portion. It is probable that the Muschelkalk lies unconformably upon the limestone : still the deposit is one of the highest known in the geological series. Crossing westward we reach about the centre of Northern Germany, and immediately south of the town of Hanover a network of mountains, made up of Cambrian and Silurian strata, that rises up out of the plains composed of the newer secondary deposits. These are the Hartz mountains, which send their spurs southward into the duchy of Nassau and down to Frankfort, while a succession of little, intervening, palaeozoic islands show their connection with the mountain masses of the Erzgebirge already described.

The metalliferous portion of the Hartz mountains stretches WNW. by £S£. a length of sixty miles, with an average

' See page 86.

Lead Mines Of The Hartz. 1 93

breadth of about eighteen miles. Its highest peak is the wellknown Brocken, and it passes through the States of Hanover, Brunswick, and Anhalt Bembexg. The structure of the range is similar to that of the Erzgebirge, and if, refeiring to fig. 37, representing that mountain range, the reader imagines the central granitic mass to be the Brocken, he will have a fair idea of the structure of the country on either side that mountain, except that the strata are very much contorted, broken, and inverted. It is an old and important mining district' The Rammelsberg mines have been worked uninterruptedly since the fifteenth century. The mines of Clausthal and Zellerfield were opened a century later.

In the Upper Hartz in Hanover there are two clusters or groups of veins, those of Andreasberg and Clausthal. Eastward there come the important mines of Rammelsberg, with mines of lesser importance farther east in Anhalt Bemberg.

At Andreasberg a space of about a mile and a quarter long by a mile broad is composed of clayey and sandy slates, which are traversed by a system of metal-bearing veins. The gangue or matrix of these is composed of fi:agments of the surrounding rocks, and contains brown spar, spathic iron, heavy spar, and quartz, the whole of which, with the lead ore, are cemented together by carbonate of lime. Besides the silver which is intimately mixed with the galena, the ordinary ores of silver, light and dark red ores, and antimonial sulphides also occur. One of the veins— the Great Samson — has been followed down to a depth of about 1,000 yards. The richest ores of this vein occur, usually, in courses of about 100 feet square. Some of the richest deposits, and those which have continued in depth, have been struck at a depth of about 360 yards.

The .veins of the vicinity of Clausthal and 211enfield are large and wide. There are six principal lines of fiacttu-e. These fractures course in nearly parallel lines from east to west, as do also the other veins of the region, generally speaking. The filling of the veins is similar to that of those of Andreas-

' See Ann, des Aftna (4) x. xiiL xiv. ; Karsten and Dfchen ArckizM,

O

194 Metalliferous Minerals And Mining.

berg. The lead ore is galena, which contains a good proportion of silver that varies from 12 to 120 ounces to the ton of ore. As a matter of observation the veins are richest where they are split up and divided, and poorest when widest and unbroken. The ramifications of the veins become at times so numerous as to form rich productive stockwerks, as at the Rosentiefe Zug.

The Rammelsberg deposit partakes more of the nature of segregated veins than of that of true lodes.

Fig. 79 represents a section of the principal orey deposit The deposit i lies between the bedding of the clay slates, A A. At a depth of about 400 feet the branch, 2, runs into the overlying slates. This mass of orey matter at its greatest

thickness was 1,900 feet long and 150 feet thick. When followed down, from i to 3 in the figure, at a depth of 800 feet these dimensions had decreased to 750 feet in length and 20 feet in thickness. It may, therefore, be terminated in depth, or it may be connected by strings with a similar large deposit below. There is little admixture of

'Mc'DBpajiT h'ar'*" gangue or earthy minerals in this

mass, nearly the whole of it being made up of metallic minerals, chiefly sulphides of lead, copper, and zinc, all mixed up together.

Nassau.* — Following the continuation of similar strata to those of the Hartz, south wards, we find, where the older Devonian rocks cover them, the lead mines of the rich little duchy of Nassau. The group of mines extends from just above the confluence of the Lahn with the Rhine, passing by the towns of Ems and Nassau. The containing rock is supposed to be of Lower Devonian age — Aeltere Rheirdsche Grauwacke — and the lodes run NE. and SW., following generally the strike of the strata. It is just possible that, as at first interpreted, these strata

' See Odemheimer, Berg umd Huttemiaesen im Nassau,

Lead Mines Of Rhenish Germany. 1 95

may prove to be of Cambro-Silurian age. The veins have welldefined walls, but they are frequently disturbed by cross faults — north and south courses. The matrix is of a quartzy nature, and the lead ore is strongly chaiged with silver. It is also associated with blende, copper pyrites, and spathic iron ore. The veins are also crossed by fissures whose sides are lined with fine crystals. The veins also vary in productiveness as they traverse different strata in depth, being rich in hard and poor in soft beds of rock. In the year 1862 there were 18 lead and silver mines in this limited region in work, which produced 97,676 centners weight of lead and silver ore, to the value of S3,ooo/.

Rhenish Germany. — West of the Nassau lodes, in the region lying north of the Rhine, between Coblentz and Cologne, as well as in the hilly district between the latter town and that of Aix-la-Chapelle, along the western outcrop of the strata containing the Nassau lodes, lie the lead mines of Rhenish Germany. Near Olpe, in Westphalia, are eight principal E. and W. lodes, with many branches, the galena containing 80 ounces of silver to the ton. The total yield of lead in the old Prussian kingdom, in 1 85 1, was 7,195 tons, and of silver 26,493 lbs. troy. The present total annual production of lead in the German Empire may be estimated at 50,000 tons.

Spain. — Before we proceed farther west, we had better take a run southward into this old lead-mining country. The mines of Spain were described by Pliny, and the Romans worked mines of lead, silver, and copper along the southern slopes of the Sierra Nevada. The mines flourished under the rule of the Moors, and declined after their expulsion. In these early workings the appliances were of a rude and ineffective kind, so that much lead was left in the slag after smelting, from which, of late years, it has been profitably extracted.

On the discovery of the rich mineral treasures of Spanish America, a rush was made from Spain to that county, so that the mineral resources of the old country were much neglected. Ot necessity, the mines of mercury, near Almaden, were worked in order to furnish a supply for the reduction of the ores from

o a

196 Metalliferous Minerals And Mining.

America. Mining, together with other branches of industry, languished during the Peninsular War ; and it was not until after the issue of a royal decree by Ferdinand, which opened the mines of the country to all nations, that a revival took place. The effect of this revival may be judged from the facts that in 1826 more than 3,000 mines had been opened in the Sierras of Gado and Laja, and that in the year 1828 the total annual production of lead ore in the country had reached 42,000 tons.

The principal lead-producing districts have been — that of Gado, in Andalusia, just mentioned ; the Sierra of Almagrera ; the country between Carthagena and Almeria; and that of Linares, in the province of Jaen.

The deposits of Andalusia are not true veins, but large amygdaloidal-shaped masses of galena. They are contained in metamorphosed limestones of probably Cambro-Silurian age, answering very likely to the Llandeilo limestone of this country.

The mines of the Sierra de Almagrera are worked in micaceous slate, which is interstratified with beds of trap and porphyry, an horizon a little lower than that of Andalusia, and answering to the position of the Shropshire lead mines. These deposits occur in pockets and bunches along the line of bedding, and die out in depth, but would probably be renewed if they were followed downwards into congenial strata. In the upper portion of these deposits lead takes the form of sulphate, in which silver is most abundant, reaching a proportion of from 130 to 180 ounces to the ton. In depth the sulphate gives place to the sulphide of lead — galena, and the oxide of iron that prevails near the surface is replaced by the carbonate of that metal Generally speaking, the ores of the Carthagena district are of poor quality, and are much mixed with blende and pyrites. Not lying deep they admit of being worked cheaply, and with modem methods of separating the silver at little cost from the lead, and improvements in the construction of furnaces, they may be worked to a profit

Linares is an important lead-mining district, and one that,

Notes on the Lead Mining District ofLinans fav Joseph Lee Thomas.

Lead Mining District Of Linares. I97

judging from the numerous excavations found there, was much worked by the ancients. The mining area is about 14 miles long from east to west, by 12 miles broad from north to south. The town of Linares lies on the south, and the northern boundary is the road leading from Madrid to Seville. The basement rock of this area, and lying in the south-west comer, is a compact granular felspathic rock, slightly micaceous. This is covered by a quartzose ferruginous sandstone, which in its turn is overlaid by a series of clayey slates, the whole being capped with a ferruginous sandstone, like that resting upon the granite. The strata dip to the north-east, and the whole series is traversed by granular felspathic dykes and veins.

The metalliferous veins traverse the whole series. There are about thirty of them, and they range — for the most part parallel to each other, between 40° and 70° east of magnetic north, with an underlie to the north-west, when they do deviate from the perpendicular. Their average width is about 3 feet, but they contract down to one, and open out into lodes 12 feet wide. The earthy filling of the most productive lodes is the decomposed granular felspar, traversed by veins of quartz, and containing in places much sulphate of baryta. At a depth of from forty to fifly fathoms, carbonate of lime and calcareous spar prevail, and are arranged in parallel layers on the walls of the lodes. Of metallic minerals, carbonates of lead, copper pyrites, and the carbonates and oxides of copper prevail near the surface, but in depth these give place to galena. When rich bunches of ore occur in the hard granular rock, they soon cut out, the ore being most plentiful in soft granular rock, where the felspar is laie grained, white in colour, and easily decomposed. In the clay slates the ore is more plentiful in those of a light blue colour of a moderate consistency, than in those of a sandy or flinty character. The ore is more persistent in the perpendicular lodes, and becomes bunchy and . irregular as they incline to a horizontal direction. Sulphate of lead is more common in the sandstone capping, and arsenical pyiites prevail more in the slates than in the granular rock.

The lodes have been followed downwards for over 200

198 Metalliferous Minerals And Mining.

yards ; some of them are worked by English companies, one of which, the Linares, has returned to the shareholders 17/. 3. 10//. for each 3/. share subscribed, and the Alamillos has returned i/. i&r. 3. on each 2/. share.

Numerous old lead mines are found near Hornachos, in the province of Badajoz, in Western Spain. Some of these have been taken by an English company, but as yet they have not reached a successful issue. Samples of lead from these mines of ordinary percentage have assayed 80 to 100 ounces of silver to the ton of ore. In the year 1878 we imported into this country from Spain and Portugal 78,380 tons of pig and sheet lead, and 1881 tons of ore. Taken with the home consumption, therefore, the total annual production of lead ore in these countries may be estimated at 130,000 tons.

Algeria. — The silver lead mines of Kefoun Teboul, near La Calle, raised 12,173 tons of ore in the year ending July 31,

France.* — The lead mining districts of France may be classified thus : Those of Savoy and the High Alps ; the east of France ; the south-east, comprising the Low and Maritime Alps, and the Pyrenees ; the Central Mountains ; and the west of France. The geological position of the mines in the High Alps is similar to that of Isre, described already in the chapters on silver.

The principal lead mines of the country are probably those of Pontgibaud, in the Puy-de-D6me, in Central France. The veins here have a NE. and SW. tendency, and they traverse slates, passing downwards into gneiss and granite. The matrix of the lodes contains a good deal of felspar with courses of sulphate of baryta, especially near the surface. The metallic ores occur in pillars or columns holding, usually, in depth, but separated from each other horizontally.

The mines of Poullaouen and Huelgoat in Vendee were formerly of much importance. There are three principal veins running 22® west of north. One of these has been traced for over a mile in length, and they have all been worked to a depth

Mints MitalUques de la France M. Alfred Caillaux.

Lead Mines Of France And Belgium. I99

of about 350 yards. They are filled with argillaceous rock like that of the couDtry, through which are threaded veins of quartz. The metallic minerals are silver galena with silver and blende. The veins traverse slaty rocks, interstratified with quartzites and porphyries.

Many remains of old silver- lead mines are found in Bretagne.

M. Cailloux estimates the total production of lead from mines spread over the districts enumerated at 14,741 tons a year.

Belgium, — Lead is mined to a small extent in Belgium. At La Nouvelle Montague, near Verviers, the ore occurs in pearshaped masses and cavities, which range over and on a line witli fissures in the Carboniferous limestone. The galena is mixed with blende, which, together with calamine, forms the m6st important ore at the mine ; the deposits will be more fully described in the chapters on zinc ores. About 1 0,000 tons of lead ore, on the average, are raised annually in Belgium ; the production for 1876, however, reaching as high as 12,422 tons.

Norway. — In Susendalen, North Norway, lead ore containing 150 ounces of silver to the ton occurs in clusters of thin veins that traverse a pale-coloured limestone of probably Cambro-SHurian age from NW. to S£.

In the south of the country, on the west side of Christiana Fiord, a great mass of granular felspathic rock is impregnated with lead ore to the proportion of 20 per cent of the mass, and the ore contains 50 ounces of silver to 'the ton. In the same neighbourhood lead ore rich in silver occurs in true lodes that traverse chloritic slaty rocks from NW. to SE.

Of the other countries of Europe the island of Sardinia produces lead annually to the extent of about 23,000 tons, and Greece 8,000 tons.

In the latter coimtry the lead is said to be derived chiefly by the resmelting of old slags, and to contain from 16 to 20 ozs. of silver to the ton.

Chapter Xxiv.

LEA D — continued.

Lead Mines of the British Isles — Statistics — Lead Mines of Shropshire — Montgomeryshire — The Van — Cardiganshire— Brief History of the Lead Mines of Cardiganshire, and Modes of Occurrence of the Ores.

The total annual production of lead ore in Great Britain and Ireland, for the three years ending December 1877, was 79,231 tons. The production for 1877 reached 80,850 tons. In 1879 it was only 66,840 tons. The rocks and strata whence this great quantity of ore was derived belong to three distinct zones, which are, beginning with the lowest : first, the Cambro-Siliuian strata of Shropshire, Cornwall, Wales, Scotland, Ireland, and the Isle of Man ; secondly, the Devonian strata of Devonshire, and possibly of part of Cornwall ; and, thirdly, the Carboniferous limestone of the Pennine chain and of North Wales. I will begin my description of the British lead ore deposits by describing those of tlie Cambro-Silurian strata of Shropshire and North Wales.

Shropshire} — The lead mining district of this county lies in its south-west corner, bordering on Montgomeryshire. It is small in extent, forming a strip of ground about four miles wide, between the range of the Stiper Stone hills on the SE., and the road from Minsterley to Bishop's Castle on the NW., and extending from the former place on the NE. about seven miles towards the latter on the SW.

It is a district of considerable historical importance— the Roman Gravels Lead Mine, at present one of the most pro-

See also Morton, ' Mineral Veins of Shelve,' Proceedings of Lhterpool Geological Society 1868-9 t Roman Mining Operations on the Borders of Wales,* T. Wright, Intellectual Observer, vol. i. 1862.

Lead Mining District Of Shropshire. 201

ductive mines of the district, deriving its name from the old surface workings left by the Romans. These old workings now appear as open trenches, rounded by time, that extend along the hillside following the course of die veins. In some places these trenches are now ao feet deep. Roman mining tools are occasionally found, and a Roman pig of lead was obtained from the bottom of the Roman vein. Another was found at Snailbeach, the chief mine of the district, and another at Snead. All of these bore the mark of the Emperor Hadrian. Those from Snailbeach and Snead are in the museum at Liverpool. The mines seem also to have been worked in the twelfUi and thirteenth centuries. The slag left by these old workers still contains a quantity of lead

t

Iii!

I, Lower Cuabrun mcb of the LaQginyntL 2, Upper CBUnbriui , probablT Ult' fala flag! anil &doc bedL 33, Sriper Stone rocV. rough bedded, uid penny iiH tnuivc.Hnd pnjbablT wowermjc id ine Condon bucofiiieAnniE group. 44, Araiif Uld Lludeilo bed±. Lead-beuioEilTaLa, with btentntified UHnDlnuivt poiphynet,

The geological structure of the district is illustrated by the general section given in fig. So, which stretches across the SW. portion of the mining area. The strata described in the section are the easterly continuation of the great Cambrian and Cambro- Silurian groups of rocks in North Wales— the Stiper Stones probably answering to the Greenstone that lies at the base of the Arenig strata. The whole of the strata are traversed by veins that have a general direction from WNW. to ESE. There are, however, others which have an opposite course, but the direction given is that of the most productive lodes. For the most part the veins are simple fissures in the strata, some

202 Metalliferous Minerals And Mining.

lying, but probably not to any great extent, along lines of dislocation.

The mineral contents of the veins vary as the latter traverse strata of different ages. In the Cambrian rocks of the Long- m3aid, on the SB. of the section, and the strata lying up to the Stiper Stones, they contain copper. In portions of the Arenig and Llandeilo beds, the deposits of lead are found, and in the overlying Bala group they are almost solely charged with baryta, which is largely worked in the district As we pass into the counties of Montgomery and Cardigan we shall see that the lead mines range along the anticlinals, where, as shown in the section, at the point where the Roman Gravels Mine is situated, the Llandeilo beds are thrown up to or near the surface.

The lead-bearing strata, 4 4, are about 5,000 feet thick. They consist of dark slaty beds, sandstones, and shales, which are traversed by greenstone and felspathic dykes, and contain interstratified trap and porphyritic rocks. The veins are most productive of ore in the hardish slates ; they are pinched in very hard strata, and become unproductive when they enter soft shale. There are three principal interstratifications of shale, which thus divide the runs of ore into four portions or floors, as they are locally called.

The veins are chiefly filled with firagments of the rocks through which they pass, cemented .together with sulphate of baryta, carbonate of lime, and quartz. The lodes at the Snailbeach Mine present some massive groups of crystals of the latter, with galena and blende grouped about the base. Fluorspar is also found in the lodes of this mine in suflicient quantity for sale. In most of the lodes, the galena and blende lie in irregular strings, which now and then open out into nests of ore. In their rich portions, some of the veius now yield 3 tons of lead ore to the fathom, but most of them, for long distances, do not average more than 15 cwt.

The richer orey portions of the lodes occur as columns, runs, or pipes of ore, and fig. 81, adapted from Moissenet,'

' Ann. cUs Mines (6), 9, p. 10.

Shoots Of Ore At Snailbeach Lead Mihes. 203

represents a longitudinal section of a lode at Snailbeach, and shows the relative width of these to the unproductive ground. In this case, however, the courses of ore to the floors in mines where the strata lie more horizontally. These courses are really ' floors ' tilted up at a high angle, the dip of thp shoots corresponding to the angle made by the intersection of the lode dipping 6?° &om the horizon southward, and the dip of the strata 50° from the horizon to the south-west These shoots of ore have in this mine been followed downwards to a depth of 500 yards.

In 1876 there were eleven lead mines in this district Of these, seven made returns of lead ore amounting to 7,713 tons.

which yielded 5,955 tons of lead. Two of the mines only, Tankerville and West Tankerville, gave proportions of silver, which in their case amounted to 3,748 ounces from 1,830 tons of ore.

Monlgomiryshire. — In the north-west corner of this county there is a small lead-producing district immediately surrounding the village of Liangynog, The ' Old Mine,' commercially known as the New Liangynog Mine, has been in work about 150 years, and in 1S76 it yielded 176 tons of ore, with 400 ounces of silver. Besides this mine, there is theCraigyMwyn, an old mine now called Ltanrhaiadr, another called Cwm Orog, and several other trials, and for the present abandoned mines.

204 Metalliferous Minerals And Mining.

These mines are all worked in the Arenig and Llandeilo beds of the Cambro-Silurian strata. Fig. 82 is an illustration of the order and position of these beds at this point, and I give it for the purpose of assisting us to understand the structure of the Van district, some thirty miles to SW., along the strike of these beds. The earthy minerals of the Llangynog lodes consist largely of the carbonates and sulphates of baryta, with carbonate of lime, and some quartz. The lodes vary greatly in thickness. I have measured the one formerly worked at Cwm Orog, 12 feet wide, where immediately below it has dwindled down to a thread. At all the mines the lodes have been most productive in the hard rocks, especially in the porphyritic rock, where, occasionally, there has been two feet of solid ore. When the lode passes into slate rock it is not so

Fig. 8a.— Section of Strata at Llangynog, North Wales.

I, Bala Limestone, a a, Bala ash. 3 3. Interstrattfied trap rocks. 444, Slate ro k% (Llandeilo bedsX 66, Arenig beds, a. Lode at New Llangynog. a' Lode at BwKh Creolas (unproductiveX

productive, and when into shale it is impoverished. In the old Rhiwarth mine a good deal of blende and some sulphide of copper are associated with the lead ore which also contains a good proportion of silver, and occurs chiefly in ribs and strings on the heading side of the lodes. As in Shropshire, the lodes are barren when they pass upwards into the Bala beds, and of this the Balch Creolas lode on the SE. of the section is an example.

In their progress southward toward Llanidloes we find the porphyries and greenstones of the Arenig and Llanidloes beds losing their massive and partially igneous character, but it is in the solid massive slaty beds, that there take their place, that the lodes are, as we shall see, most productive of ore.

As late as the beginning of the present century the Rev,

The Van Lead Mine, Montgomeryshire. 205

Walter Davies, in his Report on North Wales/ expressed the opinion that the Plynlimmon or Severn range of hills in all probability contained but few ores of metab, and that it seemed to be the most unpromising of all ranges for mine adventurers. Recent mining operations have shown that, shrewd observer as he was, in relation to a portion of the range he was mistaken in this opinion.

The veins of the Llanidloes district have a general east and west direction, with a dip to the north. The principal lode is now known as the Van, and operations have been made on this lode during the present century. At least six mines have been started, renewed, and abandoned. The Van property was leased from Earl Vane in the year 1850. After two years' unsuccessful search for the lode in a profitable condition it was abandoned. Working was recommenced after two years' idleness, when Captain Williams, of a neighbouring mine, discovered a richer portion of the lode by costeaning. Another three years' operations brought no satisfactory result, and the mine was again near abandonment Two men were, however, kept at work, and in 1862 a winze that was being sunk cut the lode where it showed good spots of ore. This discovery led to the driving of a cross-cut, which, at a distance of 150 yards from day, cut the lode in a productive state, at a depth of 60 yards from the surface. In April of the next year the first parcel of ore of 40 tons was sold, and from that date the mine has been one of the most successful in the kingdom. Its production of lead ore in 1876 was 6,850 tons, which also gave 5,136 ounces of silver.

Fig. 83 is a cross section of the lode, and of the way in which it is approached, as well as of the .strata it traverses. It is a monster lode, varying in width from 12 feet to 80 feet. It is largely filled with the redeposited material of the surrounding rock, which is traversed by veins of calcareous spar, quartz, and baryta. The ore is sometimes distributed throughout the whole mass in small bunches connected by strings, and sometimes it is most abundant near to one or other walls of the lode, chiefly the lower or heading side ; but it is seldom present in

206 METALLIFEROUS MINERALS AND MINING, force cm both ddes at the same time. It will be seen by a

Lodg composed chiefly of

Top bill lode flucu.

Linrtt hair, tad intlriap

and layen on headiu i

throuffhoiit tlic inatm of

reference to the section, fig. 83, that for ao fathoms from the

Lead Mining In Cardiganshire. 20/

surface the lode traverses dark soapy shale, and it is not very productive, the lode being filled with clay and occasional stones of ore. From this point down to 75 fathoms, as the lode traverses blue slaty rock, the upper part of the lode is also filled with clay (flucan), and the lower part is more solid and contains ore. llie flucan thins out like a wedge and dies away, leaving a solid lode. From 75 to 105 fathoms the lode traverses a blue compact slaty rock, a little calcareous in places, and arenaceous in the lower part. Here the lode contains crystals of calcareous spar and quartz, and in this portion of it the lead ore contains most silver. Taking it all through it is not a very rich lode, but there is plenty of it to cut at, and the appliances above ground are very efficient

Another great mine, the Dylefe, lies westward, on the borders of Cardiganshire. Its output in 1876 was 1,000 tons of lead ore.

In 1876 there were 37 lead mines in this county, of which 13 only made returns of ore, amounting in the aggregate to 9,041 tons.

Cardiganshire. — Journeying westward we reach the old and important lead mining district of Cardiganshire.*

The discovery of oval-shaped dressing stones in the old open workings at Cwmystwith Mine point to a high antiquity, and it is probable that some of the mines were worked by the Ancient Britons. It seems pretty certain that they were worked by the Romans. We do not, however, know anything definitely about them until the reign of Queen Elizabeth, who procured from Germany two miners, named Thurland and Hochsetter, to whom she gave great privileges. Subsequently these were extended to the Society of Mines Royal,' who ultimately sublet the mines opened and worked by them to Sir Hugh Myddelton, who worked them with great vigour and success. He accumulated a large fortune, but, like many other men of an engineering turn of mind, he spent it all in the

See Notices of the History of the Lead Mines of Cardiganshire,' by Robert Hunt, Memoirs of the Geological Survey of Great Britain vol.ii. part 2 ; also ' The Mining District of Cardiganshire,* by Warington W. Smyth, in the same volume.

208 Metalliferous Mineiials And Mining.

prosecution of another enterprise, which, in his case, was the bringing of the New River to London. The presence of a large proportion of silver led to the 'establishment of a mint at the silver mills in the district A Mr. Bushell next took the mines, and spent the proceeds in the defence of Charles I. The Esgair Hir and adjacent mines, now known as the Cambrian, were discovered in 1690. For the working of these mines a ' Mine Adventure ' was established in 1698 with a capital of 20,000/. A noticeable feature of this scheme was that onetwelfth of the profits were to be devoted to charitable uses, especially for the building of school in Wales ; but it does not seem that much money could ever be spared for these purposes. This mine adventure attracted much, attention between the years 1710-20, and it appears that the promoters got themselves into difficulty with their 650 shareholders. We next find some adventurers firom Flintshire working the Darren Mine with some others, and then little is known of the Cardiganshire mines until an account of the state of mining in the county in the year 18 lo, with a list of 30 mines, was published by Sir Samuel Rush Meyrick.

The Cardiganshire lead district extends the SW. boundary of Montgomeryshire, where it joins the mineral district of that county, south-westward to the sea in Cardigan Bay. It consists of several roughly parallel mineral zones, running in the same direction, and which correspond to the strike of the Llandeilo strata, as these come in anticlinal curves to the surface in the manner shown and explained in the Shropshire section, fig. 80, at the Roman Gravels Mine : the barren belts of ground between these zones being for the most part troughs or synclinal curves, filled with Bala, Llandovery, and Wenlock strata. These zones may be briefly described thus, beginning on the north-west and coming back eastward: the first belt consists of the range of hills that skirt the south side of the estuary of the Dovey, in which are the mines of Taliesm, Tre'rddol, Bryn yr Arian, Talybont, and others. The bulk of the galena of this zone does not contain much silver. It has a little blende, and some copper pyrites.

Lead Mining In Cardiganshire.

210 Metalliferous Minerals And Mining.

The second belt runs at some little distance along the SE. side of the first, and is the one of most historic wealth and importance, being associated with the labours of Sir Hugh Middleton. It contains a long series of mines, in some of which the proportion of silver reaches 40 ounces to the ton. Fig. 84 illustrates the position of the mines along this belt, and I shall have to refer to it presently in relation to productive depths.

The third zone runs the Devil's Bridge along the course of the RheidoL It contains the Llewemog, Powell, Consols, and other mines. For the most part the lodes here occur in a grey argillaceous rock, and become poor in soft fissile, dark slate. The lodes vary much in character, some being distinguished for silver, others for blende, and others for iron pyrites; manganese is also sometimes present

The fourth zone runs firom the centre of Plynlimon down to Lampeter. It contains the mines of Esgair y Mwyn and Loganlis. Some of the lodes contain calcareous spar and zinc ores. To the S£. is the silver lead lode of Llanfair Clydogan. The higher rocks partly cover this belt

The fifth belt ranges firom the east side of Pl3mlimmon. In its extension N£. into Montgomeryshire are the mines of Llanbrynmair and Dylefe. In the southern part of the belt the slaty rocks have frequent interstratifications of sandy matter. The lodes of this belt contain an appreciable quantity of copper pyrites.

The lodes range firom ENE. to WSW., but this direction is so varied by cross courses and other causes as to assume, especially in the smaller lodes, a zigzag shape. Most of the productive lodes are within a few degrees of this direction. Among the few exceptions are the NW. and SE. lode of the old Taiiesin Mine, the WNW. Comet lode of Cwmystwith together with a few that have a true meridional direction. The lodes, with few exceptions, dip to the north.

The amount of inclination or dip is very great — 60 to 80 degrees from the horizon. The Comet lode at Cwmystwith is

Materials Of The Cardiganshire Lodes. 211

flatter, 30 to 40 degrees, and it is observable that in this cas the lode does not deteriorate, as it assumes a flatter dip, the strata probably being favourable.

The gangue of the lodes consists primarily of quartz of different varieties, with which are intermixed fragments of the adjacent slate rock. Next to quartz, calcareous spar prevails in the lodes — a remarkable lode, consisting chiefly of carbonate of lime, occurring in the bed of the river Ystwith at Pontrhyd- y-Groes. It occurs also in large ribs at and Esgair Hir, where ores of copper and zinc occur with those of lead.

There are the usual disturbances of the lodes by horses, cross courses, ramifications, and the like, and the principal lodes are often accompanied by riders and small adjacent lodes, which are of a subsequent age.

Galena is the most abundant lead ore in the lodes. It occurs occasionally in solid ribs and masses of pure ore, but oflener in network and strings, and intimately mixed up with the non-metallic contents of the lodes.

Lead ore is most abundant where the quartz of the lode is of a cellular, drusy, and friable nature, and is usually poor when the quartz is massive and solid, and also when there is aii absence of quartz and calcareous spar from the lode. When calcareous matter abounds, copper ore, as carbonate, is often found Iron pyrites is also abundant in such conditions, as in some of the Ystumtyn lodes. Copper pyrites is also irregularly sprinkled with galena, espedally near the surface, but it is seldom found in quantities sufficient to pay for extraction. A good mass of it in a pure state was found some years ago in the old Tre'rddol Mine, and several parcels of 50 tons or so have recently been sold from Esgair Ffraith Mine, but there is no example in the district of copper having been persistently profitably worked

Both carbonate and phosphate of lead are occasionally found, the former near the surface, the result probably of the percolation of water charged with carbonic acid The latter occurs as minute crystals, which are the result of the contact of the galena with oiganic matter in a state of decomposition.

P2

212 Metalliferous Minerals And Mining.

The most abundant metallic associate of the galena is black jack or blende. Calamine is also found, but not in merchantable quantities.

Lead ore is most abundant where the lodes traverse compact, thick-bedded, slaty rock of a bluish or greenish grey colour and a soapy feel. They become impoverished when this is exchanged for soft shaly strata or gritty sandy beds. In the softer strata the lodes become indistinct and disordered. This Jact formerly led to the supposition that the lodes of the district did not bear in depth. Gradually, however, these softer beds have been pierced, and harder strata, in which the lodes again became productive, have been found below.

The lodes consisting chiefly of re-formed country rock without much carbonate of lime, are poor in lead ores. They are too ' countryfied,' as the miners say. The presence of carbonate of lime in moderate quantities as sugary spar is favourable for the production of ore.

The ore bodies have a general dip towards the west, and where the strata are favourable they are more continuous vertically than horizontally.

In the year 1877 there were 69 lead mines in Cardiganshire, of which 31 made returns of ore, amounting in the aggregate to 5,850 tons, from which were derived 47,284 ounces of silver, or about an average of 8 ounces to the ton. The mines most productive of silver were. Great Darren 26 ounces, and Goginan and Level Newydd 22 ounces to the ton. As I write I hear that Court Grange has just sold a parcel of ore, the assay of which gives 34 ounces of silver to the ton.

In the year 1878 the mines were 52 in number, of which 32 made returns of ore amounting to 6,801 tons, with 49,028 ounces of silver.

Chapter Xxv.

LEAD—cimtbmtd.

Led Mines of Canurronshire, of the lil of Man, of Conirell — lA'est Chiverton — of Devm, of the North of England— Northumbeilutd, Duibam, Westmoreland, and Cumberland — of Yorkshire, of Derbysbiie — Lead MiDM of the Limestones of Flintshire and Deobigfashire— Lead Mines ji Ireland.

Camarvonihire. — An interestii lead mining district is situated in this county. It forms & triangle, a Ibe stretched from Trefrhiw to Capel Curig forming its base, and the picturesque village of Betlws-y-Coed forming the apex. It is a district

rn. Bj.— SlCTlUK OF TUB LLANRWtT MlMIHG DlSTItCT. SKOWtMC THK COUMIATTT*

Din-Ks or uiviiaAL Mihd, ahd thui bilatior to thi Sti*ta.

I. Blae tlaty rock, t, Grey eriuy rock. lb mdil productitfc of lead vn, a. YeHowiA

fclnaidik lodi, on fcod, tut lodn pinched. 4, Duk iluc. on girly rich, s, Hud

bliR Our rock, villi fins quanz vciia : HOI much on. 5, ! tUlt, kh produciiw.

7, AlMnuioDi of liatir lock, u 4 imd s. wiih Laid ftlipUluc bsdi, loda pincbol in

which has, like many others, foimed the victim of mining gambling : sums of money having been paid for mines which could not possibly pay a reasonable interest in return, but which

214 Metalliferous Minerals And Mining.

nevertheless, if worked economically, would form moderately profitable undertakings.

Fig. 85 is a general section of the strata from Capel Curig to Llanrwst, and it will illustrate the geological position of the mine. The depths attained by the various mines are not great; the approximate depths being : Coed Mawr, 56 yards ; Bettws-y- Coed, or Pencraig, 60 yards ; Cliff, 45 yards ; Llanrwst, 60 yards ; Willoughby, or Pandora, 60 yards ; and Clementina, 100 yards. The most productive rock is a compact greenish grey rock with white spots, and it will be seen that the eastern mines, although some of them are the deepest of the district, have not yet reached this rock.

The lodes have an east and west direction, and dip south about two feet in a fathom. They are from two to four feet wide, and contain quartz and calcareous spar, the latter being most plentiful in the higher strata. The ore occurs in vertical pipes or courses, and it is noticed that these lie opposite each other in the different lodes, probably in the run or strike of the same r,=. 86.-s=:r.o or u, strata. The ore occurs in parallel Olb Pincraio MiKK, Cab- layers, as shown in fig. 86, which is a .. foI,~'[L iDch- wi*. section of a smaU lode in the old Penja, ijoiini, wiihitriigi Md craigMine. Beautiful examples of this

LumiHor lead tm. oyitallued " '

t-thanpngiLde. 33, siwy banded and comby structure maybe seen on the ore heaps at the mines. On the north-east side of the district there is a large north and south lode, which probably lies on a line of dislocation. It is known as the Gors lode. It is from ra to 30 feet wide, and is represented as containing about 4. tons of lead to a fathom high and forward of its whole width. It is now being opened on in the D'Eresby Mountain Mine, and probably before this edition passes through the press we shall know whether it may be worked to profit. The strata are of Cambro-Silurian age, and in the same stra'.a in the Point of Lleyn, near Pwllheli, are some of the most productive mines of the county. In 1878 thoe were 40 lead mines in Carnarvonshire, of which i a yielded 3,144 tons of lead ore, with 4,391 ounces of silver.

Production Of Lead Ore In Cornwall. 21 5

Isle of Man, — This island has eleven lead mines worked in strata similar to those just described. Its production of ore in 1876 was 4,353 tons. Two of the mines produced the greater part of this amount : Great Laxey 3,500 tons, and Foxdale 1,607 tons. The ore is exceedingly rich in silver, reaching as it does a proportion of 40 ounces to the ton of ore.

In 1878 the production from nine mines was 3,920 tons of ore, with 397,471 ounces of silver.

Lead mines similarly situated are worked at Lead Hills in Scotland, in Ireland, in Cumberland, and in several of the

Glubb's Shaft. x'' s 80 fathoms.

Fig. 87.— Sbction op thb Chivbrton Lead Mine.

Welsh counties besides those akeady named, but they do not call for special remarL I must, however, devote a few words to the mines of Cornwall and Devon, before I pass on to notice the lead mines worked in the Carboniferous Limestone. ComwalL—ln 1876 this county had 16 lead mines, producing 2,727 tons of ore. Of this quantity West Chiverton, near Perranzabulo, gave 1,594 tons. Old Treburget, near Camelford, 444 tons, and Herodsfoot, near Lanreath, 296 tons, leaving the remaining 393 tons to be contributed by the remaining 13 mines. The whole of the lead mines occur in the eastern half of the county. The proportion of silver produced is large, about 13 ounces to the ton. The mine most

2l6 METALLIFEROUS MINERALS AND MINING.

productive of silver was the West Chiverton, of which a section is given in fig. 87. Its yield of silver in the quantity of lead ore named was 29,925 ounces.

The lode at this mine has a general east and west direction, with an inclination or dip of two feet in a fathom to the south. It averages six feet in width, and is filled chiefly with quartz day (flucan) and carbonate of lime. The galena occurs principally in layers, although in places it is disseminated generally throughout the lode. An elvan dyke crosses the vein at about 20 fathoms firom the surface, dipping south more rapidly than the lode itself As a matter of experience it is found that in the neighbourhood of these dykes the ore is usually more abundant and richer in silver.

The mine is 160 fathoms deep, and at the 90 fathom level, a junction was formed between two branches and the main lode, and the result was extraordinary mineral riches. The lode was worth 100/. per cubic fathom for lead, and 30/. for blende. The vein here was about nine yards wide, and presented a series of ribs of lead and blende, twelve to sixteen inches in width, with ribs of quartz between. The strata traversed is only described as clay slate, and with the classing of all strata, besides granitic rocks in Cornwall as Devonian, we are left in uncertainty as to its age. One thing is, however, certain, the lead strata lie above the tin and copper-bearing rocks, and hence at a greater distance firom the central bosses of granite. We are only left in doubt as to whether the strata, like all those I have hitherto described, belong to the Cambro-Silurian, or, as shown on geological maps, to the lower part of the Devonian. In the absence of fossils to decide the matter, the strong proba* bility is that they belong to the lower group. It will be observed firom the section of the mine, fig. 87, that the course of ore has a defined width, and a westerly downward direction, which may coincide with the thickness and dip of productive strata.

The lode at Herodsfoot Mine approaches more nearly a north and south direction, its exact bearing being N. 8° to 12° W. It dips ft-om 70" to 80® east ; it varies in width firom a few inches to four feet ; has on one side, usually the heading, a

Lead Mines Of Devonshire. 21/

biecciated quartzy capel, and cavities containing crystals of quartz. Fig. 88, as given by Dr. Le Neve Foster ' from a part of this lode, will illustrate its structure. The lode seems to be the nearest approach to a profitable north and south lode we have, although, as al- g

ready observed, this I I .

also has a bearing W-|_ig:|ai„ I

wards east and west S

this lode are dark blue, —

gTeen,and drab coloured

slates, which are inter-

stratified with felspathic Z

rocks which sometimes

pass into a slaty structure. In the neighbour- — hood of the mines fos - .Z sils have been found -- indicative of a Lower

Devonian age ; but as -

we have no depths or distances given for the Fi horizon of these fossils, and as the lode itself seems to be a line of dislocarion, we are still a little uncertain as to the age of the true lead-bearing strata.

These two mmes, producing as they do the great bulk of the lead raised in the county, will suffice as illustrations of the Cornish lead lodes.

In 1878 thirteen mines yielded 1,349 tons of lead ore, with 16,456 ounces of silver.

.Zww.'— Although historically a lead-mining county of importance, Devon numbered in 1876 only ten lead mines, and of these three only made returns of ore, amountiDg alto-

' On ' The Lode at Muy Ann,' Train. Rental Seeitty tf CtmwaU, ToL ix. part I, 1875.

' See abo De la B&he, Gmlogieal Rtpert oh Ctnaoail and Detvn ; alio G.Cbiwen, Smu Accaiua tf tht Ristaitd ef MinittgiH Divetiskiit.

Middle Devonian

2l8 METALLIFEROUS MINERALS AND MINING.

gether to 437 tons with 5,890 ounces of silver, or about 13 ounces to the ton. The two principal mining districts are Beer Alston on the banks of the Tamar in the south, and Combmartin in the north of the county. Reference is made to mines in these districts in the thirteenth century, and the argentiferous nature of the lead ore was then well understood. The geological position of the lead-bearing strata will be understood from the following table of the order of the Devonian strata :

(I. PUton Slates. — Copper ore in places with galena and blende. 2. Cnccalsea Sandstone. 3. PickweU Sandstone. — Veins of hsematite with oxide of manganese.

4. Northoe Slates. — Quartz veins, but little or no metallic minerals.

5. Ilfracombe Slates and Limestones. — Horizon of the silver lead mines of Combmartin and elsewhere, copper, blende, and some antimony.

6. Martinho Beds. — Containing beds of iron along the strike of the beds.

Lower fy. Lynton Beds. — No metals. Foreland Sandstones. — Iron ores.

At Combmartin Mine the lode traverses a bed of clay slate near its junction with limestone rock ] the galena, which often occurs in courses and masses on the lower side of the lode, is associated with flucan, quartz, and white iron. In the lodes of Beer Alston, which traverse calcareous slates, the matrix consists of fluorspar, and the lead ore is disseminated through the lode in small lumps.

We now approach the consideration of the important and extensive deposits of lead ore contained in the Carboniferous Limestone of England and Wales, beginning with those of the north.

Northumberland Durham and Cumberland. — Lying on the military road known as the Maiden Way, the mining dis-

See also Westgarth Forster on Strata in the of England; Sopwith, Geological Sections of Lead Mines in Alston Moor and Teesdale ; Wallace, on Lead Ore in Veins on Alston Moor ; The Industrial Resources of the Tjme, Wear and Tees, by Armstrong and others.

Structure Of The Pennine Chain. 219

trict fonned by the junction of the three northern counties just named became known to the Romans — traces of whose ancient smelting houses still exist Not much, however, is heard of these northern mines until 1468, when Edward IV. granted to the Earl of Northumberland, with others, all mines north of the Trent Seventy years later were granted to the Earl of Northumberland and the Duke of Gloucester all the mines of Blanchland, the mines of Alston Moor, with others in the north. Several of the mines subsequently passed into the hands of the Governors of Greenwich Hospital, to whose successors they still belong. The royalties of Allendale passed through several owners into the family of the present owner, W. B. Beaumont, M.P. The Weardale mines belong to the Ecclesiastical Commissioners.

The advent of Smeaton into the district in 1775 led to a

Fig. 89.— Gbnbkal Section across thb Pbnninb Chain. England.

I, Carboniferous limestone. 99, Shales and limestones (VoroiaJe Beds). 33, Millstone grit. 4 4, Coal-measures. 5 5, Permian sandstone and limestone (magnesian).

change for the better in the methods of mining. He projected the Nent Force Level, which drains a portion of the mines. Mr. Westgarth was another of the early pioneers, who was also the inventor of hydraulic engines. The great work of the district is the Blacket Level, which was begun in 1855, near Allendale town, by Mr. Beaumont, and which is seven miles long. In 1878 Cumberland produced from 24 mines 2,667 tons of lead ore, containing 11,707 ounces of silver. Durham and Northumberland from 30 mines gave 16,869 of lead ore, containing 58,318 ounces of silver; and Westmoreland from one mine yielded 1,581 tons of lead ore, with 14,075 ounces of silver. A few of these mines are worked in the older rocks, but the bulk of them are worked in the range of hills, of Carboniferous or mountain limestone, which, from Scotland to Derbyshire, form the Pennine chain. The diagram section, fig. 89,

220 Metalliferous Minerals And Mining.

pum illustrates the general structure

luSSIr of these hiUs aU along their

g™™"" course.

. „. . . , , .„ The next section, fig, do.

High uid lov ilate iJls . 1 a V f

gives the details of the various ' , beds composing the limestone

WhiM liule , ,

p, Strata, i, and also shows the

irpmuu ud ctui position in the series occupied

PUw"™ by the lead ore deposits.

RuMaoniU] four well-defined horizons of

Uaic umutoH! lead ore, the whole of which

Sill the Great Whin Sill, and hence

L Gnu limnioiK. with above the great mass of the

J th™ fl, ond or= Sj Limestones. The

Limoiaoe DOB Umestones, 1334, with the

interveningstrata, are traversed

Sin by a vast number of lodes,

I Foor.fiuiiom luneBimc arc productive in the

I ikt™Giui.ic Umestone, but impoverished

i Thne-yud limcBone byvarious degrees in the shales

j siioiiiam hull inj and sandstones, being poorest

j Kwyud limutoiie Where the strata are soft or

FoDT-biiicimariiuyiiuie coaTse. Thcy are also most

j BocioB ot sc perpendicular in the lime

liDeBwio Stones, and incline to the hori-

BiMhic rock or Gnu zontal when passing through

i the shales : an Ulustration of

' „ .. ., this is seen in the cross section

(luia wKi undBona, Ot the JJrowngill vein, fig. t,

boui 9- ft adapted from Wallace.

the shale beds they are often

SSSKi™"?"ry'SS disordered, the ue ill.

bud id nuw, criki.y. present Thus the Dowgang

Materials Of The North Of England Lodes. 221

Nent Head and Guddamgill groups of veins have been worked u various mines in the Quairy Hazte, and down as low as the Slaty Hazle, but without profitable results, although small bodies <tf ore were present; and rich bodies of ore which have been worked on the west side of the Nent, in the four-fathom lime- Stone, have ceased to be productive when followed down into the Nattras Gill Hazle, and when followed down into the Slaty Hazle were pinched, and contained only small pieces of ore. Nearly'the whole of the profitable and moderately productive lodes have a NW. and SE. direction, and a nearly vertical dip

tia. SiCTioH OF Tm BiowmsiLL . A A, Lode.

NK The ordinary veins are intersected by N. and S. cross veins, which arc accompanied by dislocations of the strata, the beds being usually thrown up to the west When these cross veins strike the ordinary lodes at an acute angle, the point of intersection is generally rich in ore.

The minerals associated with galena in the veins vary gready in different parts of the district At the Cowper's Dyke Lead Mines, carbonate of lime and fluoride of calcium fill the veins in the great limestone, the veins presenting the appearance shown in fig. 93.

222 Metalliferous Minerals And Mining.

1 1, Great Limestone, with crack 222 running into the lode ', 3 is a central course of galena, and 3 x are lumps and spots of the same, the remainder of the lode being filled up as just described. At Nent Head fluoride I of calcium is absent, its place I / being taken by quartz. In Alston Moor, sulphate of zinc is common, but it is absent in Weardale and Allen Heads. The lodes as they pass into the sandstones below the limestones contain more silidous and quartzose matter, and

usually sulphate of zinc disap- r,o. ,,.-iu.de.nG,.at uv.,H, A good deal of car-

bonate of lime is also present. The latter also abounds in the Foiu: Fathom Limestone, as well as in veins in the Bottom and Great Scar Limestone, where it occurs in slender six-sided prisms, from three to four inches long. Where the lead ore is most abundant, these prisms are most perfect Quartz crystals are not uncommon in the limestone, as well as those of fluorspar, the whole being associated with iron pyrites. Fluorspar is generally abundant where lead ore is plentiful, although it does occur sometimes without the ore. Generally speaking the vein matter is harder on the east, in Coal Cleugh, Alston Moor, and Teesdale, than on the west, as at Allen Heads, Weardale, and Derwent Again, at Cross Fell, on the east side of the mountain, the lodes are filled with fluoride of calcium, and on the west with sulphate of bar3rta. The associated minerals exist in greater variety in the lodes of the Great Limestone than in any of the other limestones.

This limestone is about twenty yards thick. It is made up of beds of limestone parted by thin layers of shale. Some of the limestone beds have, especially where much intersected by veins, become decomposed by the action of water flowing through and remaining in them, and in the cavities thus formed are found deposits of lead ore. These decomposed parts of

Ore Flats In The Great Limestone. 223

the Great Limestone are known as ' flats/ of which there are three—* High Flat Post,* Middle Flat Post,' and Lower Flat Post' Sometimes these flats ' have not been refilled with redeposited matter, and present the appearance of caverns lined with crystals of carbonate of lime, galena, and blende. These caverns occasionally attain a large size, containing twenty cubic fathoms of space. Both the filled and the unfilled flats ' thin off" into thin layers or strings, which not unfrequently connect them with others and with the veins. They are longer horizontally than vertically, and cover large areas of the beds, those of Small Cleugh and Handsome Mea Cross Vein, shown in figs. 93 and 94 (adapted from Wallace), occupying an area of nine acres. The ore is most abundant, and the workings most extensive, in the Lower Flat

In fig. 93 the light-shaded part shows the extent of the decomposition undeigone by the limestone, and the black portions the orey ground already worked, and the fine lines are the ordinary veins.

These ' flats ' in the Great Limestone, which are of considerable extent, are worked in the Dowgan Mines of Nent Head. Also in Holy Field Mines similar flats lead ofl" fi-om the sides of the lodes. Flats also occur in the Tyne Bottom Limestone under similar conditions, lead being distributed in paying quantities in the altered portion, but they are not much worked. Where 'flats' are not definitely formed, nearly the whole of the limestone cheeks or sides of the lodes are partially decomposed, or altered, for some distance on either side.

Yorkshire, — Passing southward into Yorkshire we find in Swaledale much the same arrangement of the limestone strata as in Northumberland and Durham, as will be seen by a comparison of fig. 95, which shows the arrangement in Yorkshire, with the northern section fig. 90.

The Main Limestone, corresponding to the Great Limestone of the north, is the chief ore-bearing group of strata in

I See also PhiUips's Gwiogy of Yorkshire; Mineral Veins of Swaledale Yorkshire by Lonsdale Bradley, F.G.S.

224 Metalliferous Mikekals And Mining.

'Flats' In The Great Limestone.

i !

rf

F Iw'

226 Metalliferous Minerals And Mining.

the district It is a hard, fine, and close-grained limestone, interbedded with thin shale partings. It contains three principal layers of decomposed limestone or ' flats,' in which are also caverns containing various amounts of lead ore. These are connected by strings and veins variously prolific of ore both in the limestone and in the overlying chert. Higher still the lodes are occasionally very rich in the ' Red ' Limestone, and also in the Under Sett chert and limestone. They are more rarely productive in the underlying 27 fathoms grit, when the lodes are wide. The Third Sett Limestone, corresponding to the Tyne Bottom Limestone, has not been much worked, and, as in the north, it forms the lowest limit hitherto of mining operations. The grits and plates between the beds specified are not usually productive of lead ore.

The mining district of Swaledale, which we may take as a typical one, is about fifteen miles long by six miles broad, extending firom Richmond on the east, to Westmoreland on the west, and Wensleydale on the south, to Teesdale on the north. The lodes are neaily all due east and west, very parallel to each other, and probably continuous between the mines at which they are worked. They occur in groups. Starting on the north there is a group of two lodes runnmg through the mines, then a group of three, followed by another group of two, and at some distance farther south by another group of three.

In the SE. comer of the district, at the Grinton and Ellerton Mines, there are a few NW. and SW. lodes.

The earthy materials filling the lodes are known in York shire as riders.' When these consist simply of firagments of the containing rock-limestone, chert, or grit, it is called a primary rider. When it consists of these in a dissolved and reconstituted condition, as calcareous spar, fluorspar, barytocalcite, and quartz spar, it is called a secondary rider. When, finally, it consists of a loose earthy or clayey matrix, it is called a tertiary rider or lode. The substances mentioned comprise the non-metallic filling of the lodes. With these and the ore, sulphide of lead, are associated the oxides of zinc —

-Productive Strata Of Yorkshire. 22?

black and grey jack and iron pyrites. Most of the lodes have a non-mciallic filling of one of the above kinds, but theie aie productive lodes where metallic ore fills the whole widQi.

228 Metalliferous Minerals And Mining.

The lodes north of the River Swale are mostly true lodes, carrying strong riders, while on the south the ore lies in caverns and flats in the limestone.

Nearly the whole of the lodes are on lines of dislocation of the strata, and it has been found that the amount of the dislocation affects materially the productiveness of the lodes. An illustration of this is given in fig. 95, which is adapted from one of Mr. Lonsdale's series of similar illustrations. Where the dislocation is least, the two walls of the lodes are limestones for the greatest distance ; and as this is the most favourable condition for the production of ore, a greater vertical space of ore-bearing ground is available. When the dislocation throws up a bed of grit against a bed of limestone is the next favourable condition ; when a bed of shale against a bed of limestone is a less favourable condition ; and when shale beds against shale beds is the least favourable condition of all others.

The percentage of ore-bearing surface to the full extent of the lodes thus varies considerably, from 61 per cent, where the dislocation is under a fathom, to 31 per cent where the dislocation amounts to 13 fathoms. Of course, when the strata are in an undisturbed condition, the lodes are only productive, generally speaking, in the beds specified.

In the Top Setts ' 170 points of the lodes have been returned as productive — from the crow, chert, and limestone to the black beds and thin limestone; 148 points have been productive in the Main Setts,' consisting of the Main Limestone and chert, and 40 in the Under Setts, composed of the Under Sett limestone and chert and the 27 fathoms grit In 1876, Yorkshire had 54 lead mines, of which 23 made returns of ore amounting to 4,198 tons, with a proportion of 8,850 ounces of silver, or slightly over 2 ounces per ton.

Derbyshire. — Lead mining in this county is a very ancient industry. It is said that prior to the year 1289 the only lead mines were those of Derbyshire,* and Pryce says that Edward I.

McCuIloch's Commercial Dictionary.

' Afincralogia ComuHensis, See also Mawes' Derbyshire ; and Letters, by J. B. (J. Biden), in Mining Journal, 1877.

Lead Mines Of Derbyshire. 229

brought miners from Derbyshire to work the silver mines of Devon and ComwalL The same monarch also caused an inquisition to be made, in the sixteenth year of his reign, at Ashbum, into the rights and liberties of the Derbyshire miners. The result of this inquiry was embodied in a report, a copy of which, together with a list of the articles and customs of the Wapentake of Wirksworth, with other curious information, is contained in the Miner's Guide, or Complete Miner,' published at Wirksworth in 1810, by J. Cotes, and sold at that time by Crosby & Co., 4 Stationers* Hall Court

The great mining district of the county lies between the towns of Buxton and Castleton on the north,' and Cromford and Wirksworth on the south. It is about thirty miles long by about twelve miles broad ; the eastern half of this width being the most productive mineral ground.

In the year 1876 there were no less than 100 lead mines in the county, 50 of which )rielded ore to the extent of 2,129 tons. A number of mines yielding less than five tons each brought the quantity up to 2,264 tons, concerning which no percentage of silver is recorded. The same general arrangement of the limestone strata is continued southward into this county, and also the disposition of the lead ore and its associated minerals. There are three or four layers or courses of a basaltic-like rock, called toadstone, answering to the whinsill of the North, which run somewhat irregularly through the beds, and which pinch the lodes as they pass through them; and sometimes the lodes are quite cut off through the thickness of the dykes or beds. The various deposits of ore are locally known as 'Pipe* veins, where the ore is contained in an elongated vertical pocket; Rake veins, which are ordinary veins; and Flats, similar to those aheady described. There is nothing in the deposits themselves to require a special description, and I may conclude my description of the lead ore deposits of the whole of the Pennine chain of limestones with the remark that the deposits are, on the whole, richer where the beds form a synclinal trough than where they form an anticlinal ridge.

Flintshire and Denbighshire, — Dipping westward under the

230 Metalliferous Minerals And Mining.

Coal-measures, Permian, and New Red Sandstone strata, the limestone beds we have been considering rise again to the surface in these two counties, where they form the natural boundary between England and North Wales. From Llangollen on the south, to Flint, Holywell, and Prestatyn on the north, portions of the strata are highly mineralised with the ores of lead and zinc. Along this portion of the range there were, in 1876, in the two counties, 84 mines, of which 45 raised 5,963 tons of ore with a proportion of 26,397 ounces of silver. The bulk of the ore was raised from three mines. In Denbighshire the Minera Mine produced 3,081 tons, and in Flintshire the Talargoch Mines gave 950 tons, and the North Hendre 640 tons. In 1878 the production of the two counties w.h 7,845 tons.

The ore-bearing strata occupy two distinct zones in the series : first, and chiefly, in the lower pale-colouied limestones, I and a of fig. 96, which correspond to the Great Scar lime-

Fic. 96.— SrerioK or LiH

3WET pale-colDtiTd liraotoKL

halo. 4. Or

stones of the North ; and, secondly, in a lesser dree, in the grits and limestones, 4, and the uppermost part of 3, which correspond in an attenuated form to the ore-bearing grits and limestones of the northern counties. The strata between are unproductive of lead ore.

The veins are very numerous, and have a general east and west direction ; those profitably worked for any length of time takin that course. There are north and south lodes of great length, which mark dislocations of the strata, but these derive their mineral wealth from the intersection and junction of the east and west lodes. A good example of a true fissure vein is seen at the Talargoch Mines, near Rhyl.

Lead Mines Of Flintshire.

The lode runs through all the beds from the base of No. 4 to the bottom of the lowest limestone. It ranges from £N£. to WSW., dippmg to the north. It varies from 3 feet to 30 feet

N

ctin

Vm:A .J. ?;

Fig. 97.— Sktion or Flat Lodb at Nokth Lxad Mimb, N. Walbx

xB 100 yards.

Drift, a. White limeitoiM. 3, BluUh-blade limestone and shale. 4, Black limestone.

5, limrttonr, Flat lode.

wide, being widest in the beds No. 2, of fig. 96. It has an earthy filling of carbonate of lime, cherty matter, and Augments of the adjacent strata. It contains the sulphides of lead and zinc, the latter most abundantly. The ore is richest in metallic zinc and the lead ore in silver in the beds No. 2. The lode is not productive in the beds No. 3.

There are also 'flats' of the usual kind — those formed at the junction of limestone with sandstone beds, as at Fron Fawnog; those occurring in cavities in the limestone filled with day, with imbedded lumps of pure galena ; and flat lodes like that at North Hendre, of which an illustration is given in fig. 97. In these flats, more especially in the second kind, carbonate of lead is found to a considerable extent, as at the Westminster and Queen of the Mountain Mines, where it lies at the base of the clay in the pocket or flat, filling up the hollows of the limestone beds.

Scotland possesses seven lead mines, of which very little is known mineralogically. In 1877 four of these produced 2,706 tons of lead ore, which yielded 1 1,306 ounces of silver. An

232 Metalliferous Minerals And Mining.

attempt is now being made to resuscitate the Lead Hills Mines in Lanarkshire, which were formerly of considerable importance. Ireland. — In this island, one mine, Luganure, in the county of Wicklow, yielded in 1876 1,825 tons of lead ore, containing 6,840 ounces of silver. The mine is worked in strata of the same age as those of Shropshire, Montgomery, and Cardiganshire, already described As there are no distinctive features to describe, this reference will conclude my description of the lead-ore deposits of the British Isles, and I will pass on to notice those of America.

Chapter Xxvl

LEAD—CotUmued,

Lead Mines of North-Eastem America — Canada — New England States- Wisconsin, Illinois, and Iowa — Carbonate ofLead in Colorado — Sum* mary and Deductions.

Eastern America. — Again crossing the Atlantic, and following the method hitherto pursued, I will first notice the lead mines of the country east of the Appalachian Mountains, beginning on the north and following the mines southward. We will then proceed westward to Wisconsin, Colorado, and farther west

Canada, — In the early part of the year 1878 the Frontenac Lead Smelting Works shipped four truck-loads of lead, said to be of good quality, but we lack at present any information as to the stratigraphical conditions under which the ore was obtained.

New England States, — Lead ore deposits occur frequently in the clay slates and metamorphic rocks south-east of the Appalachian chain of mountains. For the most part these are seated deposits, but sometimes they are found as strong, well defined lodes. The ores are a good deal mixed with inferior substances, and mining has not been very successfiiUy pursued. Often the veins consist of barren quartz, and the segregations lie between intrusive rocks and limestones, probably of Llandeilo age. One of the best examples given by Mr. Whitney was at Middleton, on the right bank of the Connecticut The galena occurs here in a vein 10 to 20 inches wide, traversing micaceous slate, lliis is partly filled

MeiaUU WeaUh of the United States,

234 Metalliferous Minerals And Mining.

with quartz, that occurs in crystallised plates or combs, and is associated with calcspar, crystals of fluorspar, and sulphate of

baryta. Distributed in this matrix is galena,

along with blende, iron pyrites, and, rardy,

yellow copper ore. The vein sends shoots

along the bedding of the strata, as shown in

fig. 98, which are often productive of ore for

in'cacbousSlats some distance from the main lode. The

CoNNBCTicoT. galeua averaged 50 ounces of silver to the

ton, the fine-grained yielding only one-third the quantity given

by the coarse ore.

New York, — The arrangement of the strata continues the same in this State, and lead ore has been obtained since the year 1835 the veins of Ryssie, in St Lawrence county. The principal vein — the Coal Hill Vein — is nearly perpendicular ; it varies in width firom 2 to 4 feet it ranges firom SSE. to NNW., and its gangue is calcareous spar, which often assumes a beautifully cryst£dline form. The galena occurred in a pure state as a rib about 10 inches wide, in the midst of which were fine crystals of the ore. There was not much silver, but at one time the lode was estimated at the value of 25/. per fathom.

Some of the finest crystals of carbonate of lime in the world have been derived fi-om this lode, one, preserved in Yale College, weighing 165 pounds.

A similar arrangement is observed in the Union vein of the same locality, and similar deposits in veins and segregations occur in Lewis and Columbia counties.

Wisconsin Illinois and Iowa} — Proceeding westward we reach an important lead region at the junction of these three States. It is bounded by the river Wisconsin on the north, and the Mississippi on the west, running eastward along the former river for 70 or 80 miles, and northward along the latter for about the same distance. The deposits seem to have been

' Geology of Wisconsin Moses Strong, 1877 ; Engintering and Mining Journal of JSew York vol. ; WhiUiey*s Metallic Wealth,

Lead Ore Deposits Of Western North America. 235

known to the aboriginal inhabitants. Attention was attracted to the district in 1700 by Le Suer. In 1788, Dubugue, a French miner, obtained a grant of land that now includes the town that bears his name. He continued mining until his death, in 1809. Mining operations were carried on under various airangements and with varying success till 1839, when a geological survey of the country was made by Dr. Owen and 139 assistants. In 1847 mines yielded of metallic lead 24,145 tons. In 1853 the yield had decreased to 13,307 tons. In 1876 the production of the whole region only reached 6,812 tons.

The following is the order of the strata, with their English equivalents :

Cambro- Silurian

Bala Limestone

Llandeilo Beds

Cambrian-

Upper Lower

Lingula and Tremadoc Beds

Bangor Beds

Niagara Limestone.

Galena Limestone — Lead-bearing

rock. Trenton Limestone — Fossils, large

orthoceratites, favosites, &c. Sandstones, shales, and calcareous

beds. Lower Magnesian Limestone — , Lower limit of lead-bearing rocks. White Potsdam Sandstone. Fossiliferous Slates. Dolomitic Limestones. Dark Sandstones.

It will be seen that the geological horizon of the leadbearing strata is the same as that of the Llandeilo beds of Great Britain, the difference being that in this American region there is a greater abundance of calcareous matter than there is in the British Isles. The principal mines are worked in the Galena limestone, the productive lodes penetrating at times the underlying Trenton limestone, and occasionally the Lower Magnesian limestone ; but their productiveness ceases when they enter the Potsdam sandstone, corresponding to our Lingula and Tremadoc beds.

The Galena limestone is a yeUowish-grey, hard, compact

236 Metalliferous Minerals And Mining.

crystalline rock. It contains numerous small cavities, filled with a softer material, and somedmes lined with crystals of caldte. It is thick-bedded in its upper portion, and consists of thin layers in its lower part. It contains the usual Llandeilo fisssils. Distributed throughout it, but occurring more abundantly in its middle part, are layers and accumulations of flints coindding with the bedding. The metallic deposits occur, as shown in fig. 99, in vertical cracks or crevices, as they are locally called, I ; in flats or ' flat openings,' i ; and in pockets, 3. The cracks, i, opening out at times into cavities, as shown at A, in %s. 100 and loi.

Fio. SiCTioB or CJU.CHA LiHwTOBt SHOWING Loots, Fl*t, AMD Pocitm, I, Lode, a a, FUu. 3, Pockn.

The workings have been carried down in this limestone to a depth of about no feet

The vertical veias or lodes have an east and west direction. Their usual width is from one to two feet, but they open out into cavities 30 feet across. They arc filled with a dark red ferruginous day, together with calcspar, and fragments of the adjacent rock in which loose lumps of ore are indiscriminately distributed. In the flats the matrix is usually calcspar, in which lumps of galena occur, and which alternates in layers with calamine, blende, and iron pyrites. These flats are connected by irregular cracks with the vertical fissures, i, bearing ore.

Lead Deposits Of Wiscoksin. 237

The ore deposits lie above a group of fossiliferous blue limestones, and it has been suggested that the gases evolved in the decomposition of so much animal matter as must have once existed, may have had a material influence in detennining the precipitation of the lead from the overspreading plombiferous solution.

The detailed section of the limestones at Minetal Point, Wisconsin, is as follows :

f Yellciw Galena Limestone, 75 fel. Chief Lead Deporit j Upper Letd OpenioK, 3 feet to 8 feet.

I Glass Rock or Blue Limesloae, g feet to 13 feet. J Middle Lead Opening, SfecttoSfeet Spongy limestone, 13 feet to 18 feet.

j Lower Lead Opening, 4 feet to 8 feet. white Soft Galena Linettone, I foot to a feet.

Lead deposits are opening out on a large scale around the upper reaches of the Missouri and Madison rivers, buf we

238 Metalliferous Minerals And Mining.

have not as yet many particulars concerning them. The production for 1877 reached the laige amount of 22,000 tons, and it is probable that the conditions under which the ore is found are similar to those just described of the Wisconsin region, the ore lying in cracks and flats of limestones of a magnesian character, with Cambro-Silurian fossils.

The conditions under which the ore is found associated with that of silver in Colorado Nevada Utcth and the Western territories generally, have already been noticed in the description I have given of the Emma Mine, the Comstock lode, and the Ruby Hill deposits. It only remains, therefore, for me to

Fig. xos.— Section op Strata in California Guuch, Colorado, showing PORTION or Carbonate op Lkao Deposits.

r, Porphyritic rock, Z2 to loofeet thick. 3, Thin bed of white clay. 3, Carbonate of lead bied, i to 90 feet thick. 4, Oxide of iron, x to 6 feet thick. Limtone. 6, Clay slates. 7, Quartzites and metamorphic rocks, resting upcm gneiss.

notice the recent discovery of extensive deposits of carbonate of lead in California Gulch, Colorado.

This gulch forms the bed of one of the uppermost tributaries of the Arkansas River. It lies just south of the Park portion of the Rocky Mountains, on the eastern side of the Great Divide. About sixteen years ago it was the busy scene of rich surface gold mining operations, and the miners frequently noticed the great weight of many of the stones and boulders that lay in their way ; but as there was not the usual appearance of lead ore no further notice was taken.

See Engineering and Mining Joumai of New York vol. xxv. p. 4a

Carbonate Of Lead In Colorado. 239

The presence of carbonate of lead in these heavy stones was first recognised about three years ago by Mr. A. B. Wood, of Ann Arbour, Michigan. Further search revealed the mineral in situ. The region was covered with prospectors before a month was out, and the hillsides soon became riddled with shafts and levels. An examination of the majority of these shafts gives the following as the geological position of the ore, fig. 102.

The ore bed has usually been reached within a depth of 100 feet from the surface. It is found in horizontal masses extending some distance in all directions, and having a thickness of firom 6 inches to 20 feet Carbonate and sulphate of lead are the prevailing ores, but lead ore in all oxidised varieties occur. The bed varies in its composition. In places it is a compact heavy grey rock, in others it is soft and tough, but similar in colour to the first, and in places lines of darkerlooking mineral run through it. The character of the ore contained is, in the first variety, 65 per cent of lead, with firom 10 to 20 ounces of silver; in the second, 65 per cent of lead, with from 20 to 40 ounces of silver ; and in the third about the same quantity of lead, with firom 150 to 2,000 ounces of silver to the ton of ore, with the addition occasionally of an ounce or two of gold.

The limestones and underlying schists are for the most part in a metamorphic condition, and there can, I think, be no difficulty, from the presence of the porphyry above and the quartzites and gneiss below, in recognising their position as the equivalent of our Cambro-Silurian Llandeilo bedi. The total production of lead ore in America in the year 1877 is given at 73,000 tons.

I have now enumerated the principal lead ore deposits and regions of the world, and a consideration of the phenomena and conditions described seems to lead to the following conclusions :

The lowest horizon of lead ore in workable quantities lies above that of copper and the other metals before described, being in the Llandeilo and Arenig strata of this country, and

240 Metalliferous Minerals And Mining.

their equivalent elsewhere. That lodes and deposits cease to be productive as soon as they enter the underlying Lingula and Tremadoc schists, and sooner where the Arenig strata are of a soft shaly nature. That the productive zone does not extend into the overlying Bala beds and strata of the Upper Silurians. That a productive zone of limited areas, as in Devonshire, and possibly in some of the Western American mines, lies in the middle limestones and slates of the Devonian group of strata. That the third and highest ordinary horizon is found in the Carboniferous limestone, this horizon being divisible into two zones, one in the pale-coloured massive limestones near the base of the series, and the other in the limestones and grits near the summit, the intervening dark limestones and shales being barren. That the largest proportion of silver is contained in the ore derived from the Cambro-Silurian strata. That both in these older strata and in those of the carboniferous series the lead ores from the lodes containing most plentifully the ores of zinc are richest in silver. That the lodes inclining most to an east and west direction, and most perpendicular in their dip, are the most persistently productive of ore. That the north and south lodes are, with a doubtful exception or two, unprofitable to work, and that the ore in these, which are cracks along lines of disturbances, lies in a rolled drifted form, and is probably in this state of subsequent origin, together with the fissures in which it lies, to that of the east and west lodes of any horizon*

Ml

Chapter Xxvil

General Remarks— Ores of Zinc — Zinc Ores of Siberia, Hungary, Silesia, Sardinia, Algeria, Belgium, Great Britain and Ireland, America, Eastern America — New Jersey — Zinc Ores of the Lead Region of Wisconsin, of the Western St&tes—Concluding Remarks.

The application of this metal to the useful purposes of life has been greatly extended during the last thirty years. The coating of sheet iron with it has alone vastly increased the demand for tlie mineral In Great Britain and Ireland, for example, the production has increased from about i,oootons in 1850, to 24,485 tons in 1877.

Zinc occurs in nature combined with carbonic acid, oxygen, silica, sulphur, sulphuric acid, and more rarely with alumina. Its ores, the specific gravity of which ranges about 4*5, and their hardness 4 to 5, may be thus enumerated :

Carbonate of Zinc— Calamine. — Smithsamte, — Chemical composition : pure zinc, 51*44; oxygen, is'io; carbonic acid, 35*46. These principal constituents are often displaced by protoxide of iron to the extent of 2 to 3 ; manganese, 3 to 7 ; and magnesia, o to 3. In colour it ranges from colourless through dirty white, yellow, and grey, to brown. It is one of the common and most useful ores of zinc. Its varieties are —

Herrerite. — A mixture of the above with nickel oxide.

Kapnite, — The same, with 15 to 37 per cent of protoxide of iron.

Zinc Bloom, — An earthy carbonate of zinc, containing 69 per cent of zinc oxide with 15 per cent of water.

R

242 Metalliferous Minerals And Mining.

Oxide of Zinc— Zincite. — Red Zinc Ore. — Chemical composition : zinc, 80, oxygen, 20, varied by 3 to 12 ot manganese' peroxide. Blood or hyacinth red, with orange yellow streak ; found at Franklin and Sterling in New Jersey in foliated asasses, and laminated flakes or grains. Its variety is —

VoltziU. — Containing a proportion of sulphur, forming a link with sulphide of zinc.

SiucATB OF Zinc. — Electric Calamine. — Galmd, — Chemical composition : zinc oxide, 66*8, silica, 257, and water, 7'S. Colourless or white, to grey, yellow, green, brown, and blue. Occurs as columnar, fibrous, granular, and earthy. A valuable ore of zinc Its varieties are :

Aurkhalate. — Containing some zinc carbonate and copper.

Franklinite, — A mixture of zinc with manganese and iron, forming practically an ore of iron.

Hopeite with a proportion of phosphorus ; a rare mineral. Willemite, oxide of zinc, 72*85, silica, 27 'is.

Sulphate of Zinc. — White Vitriol. — Goslarite. — Chemical composition: zinc oxide, 28*2, sulphuric acid, 27*9, and water, 43*9. Of a stalactitic and incrusting form. Nauseous and astringent taste, and ranging in colour firom white to brown. Used in medicine and dyeing.

Sulphide of Zinc — Blende. — Zinc Blende, — Black yack, — Chemical composition : rinc, 66*8, sulphur, 33*2, varied by iron i to 15, and cadmium o to 3. The most abundant ore of zinc In colour ranging from yellow, green, red, brown, and black ; of a resinous and waxy look, and from opaque to semitransparent in appearance.

Zinc ores, as we have seen, are largely mixed with those of lead, and the mineralogical and stratigraphical conditions under which they are found, have already been pretty fully described in the chapters treating of the ores of lead. I will, therefore, only briefly describe further a few of the principal zinc ore deposits of the world

Zinc Deposits Of Germany. 243

The carbonate of zinc occurs in Siberia, Hungary, and in the mines of Saxony and Bohemia.

North Germany. — In Silesia in the district around Famowitz and Ben then, the Coal-measures are developed, and there are numerous collieries and ironstone mines. Covering the Coal-measures over a considerable tract of country, and extending into Russia, is a limestone supposed to be the equivalent of the Muschelkalk, or middle member of the New Red Sandstone series. This limestone occurs in beds of ordinary thickness, and in its upper portion it frequently assumes the form of dolomite. Beds of calamine occur between the dolomite and the ordinary, limestone following the line of junction. There are red and white deposits, the red being associated with red clay, and the white with white clay. The aggregate thickness of the deposit varies from 3 to 12 feet, with an average of 6 feet. The percentage of metallic zinc in the deposit averaged in 1876, 11-84 per cent, the white variety being the richest The ores are mixed with galena, and contain a quantity of cadmium. The deposit is made up of a succession of thin strata, and the metallic ores seem as if they had been precipitated on the floor of a tranquil sea. There are also irregular deposits of calamine mixed with the ores of iron. There were 64 zinc mines in work in 1876, the production from which is given at 449374 tons of zinc ore, of the value of i/. y. 2d. per ton.

In the Russian portion of the deposit the production in 1874 was about 2,000 tons.

In Sardinia are large deposits of a mixture of the carbonate with the silicate ores of zinc, which occur in Silurian limestones. The lodes or cavities are described as from five to twenty-five fathoms wide, with a north and south direction, coinciding with the strike of the beds, so that probably what are described as lodes are only mineralised beds.

The ore lies in irregular masses, which are sometimes 600

yards long, and these are connected by thin strings of ore. In

places the zinc gives place to lead in depth.

R 2

244 Metalliferous Minerals And Mining.

Some rich lodes occur in the mountains that run across the north of Spain, near the southern shore of the Bay of Biscay, between Santandar and Asturia. The lodes range from six to eigt feet wide. The lodes are well defined, and contain very pure ore — calamine, containing 52 per cent of metallic zinc. At Bien Venido, 35 miles west of Santandar, the lodes cross each other, and form a network of calamine deposits.

In Algeria the zinc mine of Hamman NlDails, on the Bone and Guelma Railway, is equipped for cm output of 10,000 tons a year.

Belgium.' — This is a great zinc-producing country. The principal deposits of the ores lie in the highly mineralised country between Lifege, Aix-la-Chapelle, and Verviers. The geological structure of the country is as shown in fig. 103, but the rocks are greatly disturbed and contorted.

Fic. 103.— Section of Strata Li&gs and Verviers.

I, QuarUoae slates (Devonian), containing layers and veins of haematite and calamine, a, Limestones, some beds dolomitic 3, Quartzose slates and fine-grained sandstones. 4, Limestoaes. with beds, pockets, and ramifications of calamine. 5, Coal-measures. A B, Zinc ore beds.

The oldest of the Belgian zinc mines is the Vielle Montague, at the village of Moresnet, near Aix-la-Chapelle. This mine is said to have been worked by the Spaniards 400 years ago, but the actual records do not reach back beyond the year 1640. The deposit was worked by the State until the year 1806, since which date it has been worked by a public company. It occurs as filling, or as once filling, a space in the midst of limestone strata about 1,500 feet long, fi-om NE. to SW., 700 feet wide, and from 200 to 250 feet deep. It has been worked as an open

Ann, des Mines (4), 5, 165.

Production Of Zinc In Belgium. 245

qtiirry, in steps or galleiies all round, of which an idea is given in lig. 104.

The straU conuining the zinc ores are divided into two parts by tlic bed of limestone, The ore is of two kinds : the red containing 30 to 34 per cent of zinc, together with a deal of ferruginous matter, and the white yielding about 46 per cent of zmc, and which is, of course, the most valuable. The company by which this and neighbouring deposits are successfully worked, own the Sardinian and Algerian mines just referred to, as well as some in Sweden, which are worked in lodes in older strata. The production of sine by this company from all their mines was, in 1877, 68,095 tons, against 54,569 tons in 1876. The average production of zinc in Belgium for the years 1874-5-6 was 70,284 tons.

France. — The production of zinc in this country, as given

FtC lO.— DiAOlAll II

by M. Cailloux, was in 1869 1,000 tons. Possibly it is now double the amount

Great Britain and Ireland. — Turning now to the British Isles, we have already seen that the production of zinc has increased from 1,000 tons in 1850 to 34,485 tons in 1877. The price pa ton of the ore ranged downwards from 4/. 61. 6d. in January, to 3/. i2f. 3*/. in December, the average price being 3/, 17J, 44. The ore was produced by 57 mines, which were also lead mines. The following table' will show the quantity

246 Metalliferous Minerals And Mining.

raised in each district, and the nature of the strata whence it was derived :

Naof Mines

Locality

Cambro- Silurian and Devonian Stntta

Carboniferous Lime* stoae Stnta

s

Cornwall Shropshire Yorkshire

tons . qrs. 4,991 2 0 561 13 0

tons arts. qn. 4 17 0

Derbyshire . Cumberland .

2 14 I 1,731 10 0

Cardiganshire Montgomeryshire . Denbighshire. Flintshire Carnarvonshire

588 3 2 2,714 16 0

3H I 3

2,388 0 0 1,873 4 0

Radnorshire .

87 0 0

—

Isle of Man . Scotland

9,043 H 2 145 0 0

Ireland .

no 00

Total

18, 555 10 3

5,930 5 I

It will thus be seen that only one-fourth of the quantity raised was obtained from the Carboniferous limestone of this country. It is noticeable, however, that the ores from the limestones fetched the highest pnce. The mines producing the largest quantities were in Cornwall, West Chiverton, fig. 87, 3,660 tons ; Shropshire, Roman Gravels, fig. 80, 290 tons; Cumberland, Nenthead, 1,003 tons ; Cardiganshire, Florida, 286 tons; Montgomeryshire, Van, fig. 83, 2,404 tons ; Denbighshire, Minera, 1,971 tons; Flintshire, Talargoch, 1,855 tons; Carnarvonshire, Pandora, 195 tons ; Radnorshire, New Cwm Elan, 87 tons ; and Isle of Man, Great Laxey, 8,645 tons. The Scotch mine was the East Black Craig, Kirkcudbrightshire, and the Irish, Connoree, Wicklow. By referring to the chapters on Silver and Lead, it will also be seen that the lead mines returning the largest quantities of zinc ores are also those yielding the largest proportion of silver, for instance. Great I-axey, West Chiverton, Van, Talargoch, and Minera. In Anglesea, the bluestone deposit, referred to on page 143, is now opened up, and premises to yield

Zinc Ores Of North Wales. 247

a large quantity of zinc, with its associated metals. TVo mmes in Carnarvonshire also — D'Eresby Mountain, which has a wide north and south lode, and Aberllyn, a neighbouring mine, through which the same lode is said to pass — are much spoken of at the present time as likely to be laige producers of blende.

In the older rocks the zinc ores occur in lodes along with galena. In the Carboniferous limestone this is also the case, but, as in Belgium, there are in places large decomposed portions of the limestone and shale, which are partly refilled with the ores of zinc. To some extent this is the case with the Carboniferous limestone of the North Wales border, but nearly the whole of the zinc ores now raised in the district is obtained from the two great lodes worked for both lead and zinc at the Talargoch Mine near Rhyl and the Minera Mine near Wrexham.

Calamine is raised to a good extent at the Park Mines near Minera, but the common ore of zinc in the district is blende. In the lodes the blende is intermixed with galena, usually occupying the highest place, and it is richest in metallic zinc when derived from the beds 2 of fig. 96.

America. — In all the mining districts of Eastern America zinc ores are found, both associated with lead, copper, and iron ores, and also in separate deposits. An example* of the

Fig. 105.— Ssction op Strata nbak Spakta, Niw .

I, Slaty

6, Fettpaihic rock.

rock, with felspathic dykes, a. limestone. 3, FraiiUimt& iroa era, with sine, to 30 feet wide. 4, Red oxide of nac, 3 to 9 et wide. 5, Oyttallioe Hmeatooe.

latter may be taken from a range of hills near Sparta, Sussex County, New Jersey, fig. 105. It occurs in a limestone which

248 Metalliferous Minerals And Mining.

is highly crystalline, probably from its connection with intrusive dykes of quartzose and felspathic ash. Jt is probably of Uandeilo age. The ore is made into a white oxide, which is used instead of white lead for paint

In Pennsylvania, near Friedensville, deposits occur in beds of blue limestone of probably the same range as those just described. There are several parallel beds of an approximate aggregate thickness of 50 feet The ore here is almost entirely a sOicate of zinc of poor quality.

In the lead region of Wisconsin, Illinois, and Iowa, already described at page 235, both calamine and blende are largely associated with lead ores. The production of this region in 1876 is given as 5,000 tons of calamine and 7,000 tons of blende.

American miners are now turning their attention to the utilisation of the ores of zinc contained in the mines of the Western States, along with the ores of silver and lead Enormous and extensive deposits, which have hitherto been neglected, are reported as occurring in dose proximity to the mines of the richer metals at Georgetown and Mount Lincoln, in Colorado and Jefferson City, Montana. The ores are sulphides, and they are associated with galena and pyrites. The metallic composition of these ores is shown as follows :

Silver

100 to 1,000 ounces to the ton.

From the foregoing remarks it follows that zinc ores are closely associated with those of lead ; that frequently a lode containing blende near the surface holds lead in depth, hence the saying of the miner, ' Black Jack rides a good horse ; ' that it has much the same stratigraphical range, general and particular, as lead, running rather higher into the series of rocks, lead ending in the limestones and grits below the Coal-measures,

See Engineering and Mig Jourtud of New Ycrk vol. xxv. p. 53.

Zinc

I.ead

Georgetown

6 per cent.

Mount Lincoln

7 „

Jefferson City

10 „

Summary Of Zinc Deposits. 249

and zinc continuing up to the middle of the New Red Sandstone or Triassic group; that, in addition to occurring in lodes, it occurs in large portions of the strata locally altered, and in stratified beds covering a laige area, and that it was, and is, more abundant in nature than any of the metallic ores previously described.

k

Chapter Xxviii.

Iron,

Wide Distribution- Native Iron — Ores of Iron — StratigTaphical Groups of Iron Ores — Iron Ore Deposits of India — Austria— Germany — Nassau — Other German States— Sweden and Norway— Belgium — France— Spain — Algeria.

The ores of iron are more widely distributed throughout nature than the ores of any other metal. It would be difficult indeed to say where, in one form or other, the metal is not present. We have already seen how largely it is associated with the metals we have been considering. It gives the colouring matter to most rocks, and one can hardly pick up a stone which does not contain a proportion of it I need hardly say that it is as useful as happily it is plentiful and cheap. Nor need I here enumerate the many purposes of life to which it is applicable.

Iron occurs in a native form, and as forming an alloy with nickel, which is usually the case in meteoric iron. It also occurs plentifully in combination with oxygen and sulphur, as well as in a less degree with various acids and other ingredients.

The specific gravity of its ores ranges about 6, that of native iron reaching nearly 8, and that of the most workable ores about 5. In hardness it ranges from 4 to 7. The following are the forms and combinations in which the metal is found :

Native Iron. — Occurs as meteorites, which in some instances have fallen to the earth of great size. One from Texas, which is preserved in Yale College, weighs about fifteen hundredweight. It is made up of from 90 to 92 per cent, of iron, and 8 to 10 of nickel

Ores Of Iron. 25 1

In some meteorites small proportions of cobalt, copper, manganese, and tin, with occasionally a little phosphorus, are found.

Comb In A Tions Of Iron And Sulphur.

Bisulphide of Iron. — Iron Pyrites. — Chemical composition : iron 467, sulphur 53-3. Colour, yellow with a brownish streak. Distinguished from copper pyrites by breaking under a blow, and in being too hard to cut with a knife. The most abundant ore of iron, of little use in iron manufacture, but forming the great source of the sulphur, sulphuric acid, copperas, and to some extent the alum, of commerce. Its varieties, differing chiefly in some particulars of shape or crystallisation, are : Cockscomb pyrites Hepaiic pyrites Radiated pyrites, and Spear pyrites.

Sulphide of Iron. — Magnetic Pyrites.— Chemical composition : iron 60*5, sulphur 39*5, rather redder in colour than the last, not quite so hard, and is slightly attracted by the magnet.

Arsenical Pyrites. — Mispickel. — Chemical composition : iron 34*4, sulphur 19*6, arsenic 46*0. Cobalt to the extent of from 4 to 9 per cent sometimes taking the place of the iron. Silver-white in colour, and hard, striking fire with steel. Its variety is :

SecupyritCy which contains a less proportion of arsenic.

Combinations Of Iron And Oxygen'.

Magnetite. — Magnetic Iron. — Chemical composition : iron 72-4, and oxygen 27*6. The most important ore of iron in the north of Europe. Strongly attracted by the magnet, being itself highly magnetic.

Specular Iron Ore. — H-imatite. — Chemical composition : iron 70*03, and oxygen 29*97, varied by different proportions of titanium, chrome, or silica. Colour, ranging from deep red in the earthy ores, to iron black and steel grey in the purer varieties. The variations of this ore are very numerous, and comprise the following, which are all more or less valuable :

Clay ironstone.

252 Metalliferous Minerals And Mining.

yaspery clay iron, — Compact, and of a brownish jaspery red colour.

Lenticular argillaceous are, — A red ore made up of small flattened grains.

Micaceous iron, — Specular iron, with a foliated structure.

Oligiste iron, or in?n glance, — Varieties of specular iron.

Red chalk. — A compact red mixture of iron and lime.

Red hcemcUiie. — Iron and clay of a deep red colour.

Red ochre,\xotiy with a preponderance of fine clay.

Specular iron, — Of a metallic lustre, and highly crystalline structure.

Brown Iron Ore. — Limonite. — Chemical composition: iron 60 o, oxygen 25*6, and water 14*4, varied by silica, alumina, or phosphoric acid. A valuable and abundant ore of iron. Its varieties are :

Bog iron ore, — Occurring in lakes, bogs, and low grounds, containing from 30 to 50 per cent of impurities, and phosphoric acid up to II per cent

Brown hcemaiite, — The kidney-shaped and stalactitic haematite ores.

Brown ochre, yellow ochre.

Brown and yellow clay ironstones,

Gotheite, — Chemical composition : peroxide of iron, and 10 water, with proportions of silica and manganese.

ThfgitCy Turginsk. — Peroxide of iron 94*15, and 5*85 water.

Franklinite. — Chemical composition : iron 66 to 69, sesquioxide of manganese 15 to 18, and zinc 10 to 17 Its variety is :

Dysluite. — Which contains about 30 per cent of alumina.

Titanic Iron. — Ilmenite. — Chemical composition : peroxide of iron, with from 8 to 53 per cent of blue oxide of titanium. Mencucan, Crichlonite, and Mohrite are other names for the same or similar ore. A notable variety is :

Iserine, or magnetic ironsand, which is probably magnetite, mixed with peroxide of titanium.

Chromate of Iron. — Chromiie, — Chromic iron, — Chemical composition: peroxide of iron 19 to 37, magnesia o to 10,

Ores Of Iron Continued. 253

chrome peroxide 36 to 60, and alumina 9 to 21, with variations of o to 10 of silica. Used in various proportions for paints and dyes.

CoLUMBiTE. —7V//.— Chemical composition : protoxide of iron 14 to 17, protoxide of manganese 37 to 4*8, niobic or culumbic acid 78 to 81, with small quantities of the oxides of tin or copper.

TUNGSTATE OF IrON AND MANGANESE. — WOLFRAM. —

Chemical composition : tungstic acid 76, protoxide of iron 95 to 20, protoxide of manganese 4 to 15, with small proportions of lime and magnesia.

Silicates of Iron. — The compounds of the oxides of iron with silica are very numerous, but they are not of much interest commercially, and I refer the reader who desires to understand them scientifically to books devoted to mineralogy.

Sulphate of Iron. — Copperas.— Chemical composition : protoxide of iron 26, sulphuric acid 28*8, and water 45*2. Formed by the decomposition of iron pyrites.

Carbonate of Iron. — Spathic Iron. — Sparry Iron. — Chalybite. — Chemical composition : protoxide of iron 62*6, carbonic acid 37*4, with small quantities of lime and magnesia, and occasionally manganese up to 25 per cent An impure variety is the clay ironstone of the Black Band seam, which is found near the summit of the Coal measures in Great Britain.

ViviANiTE. — Blue Iron. — Chemical composition, when pure, protoxide of iron 42, phosphoric add 29, and water 29. Occurs occasionally in great masses in the earth under old slaughterhouses, and in indigo coloured crystals at St Agnes in Cornwall, and elsewhere — used as a pigment

Arseniates of Iron. — There is a number of minor combinations of the oxides of iron with arsenic, but the remark made concerning the silicates is applicable to this group of iron ores.

Stratigraphically the deposits of iron ore may be comprised in three great geological groups. The first and oldest containing those from the Laurentian rocks to the Carboniferous limestone, inclusive ; the second the ironstones of the Coal measures ; and the third the strata from the Permian to the most recent

254 Metalliferous Minerals And Mining.

deposits. The whole of the deposits of iron ore belonging to these three groups are so numerous that a desciipdon of them all would be far beyond the limits of this bocL It will be sufficient, I think, if I select for description a few of the more distinctive and typical examples of the ironstone deposits of the worid, and I will begin, as before, in the East, with a brief reference to some of the iron ore beds of India.

India. — Valuable beds of magnetic iron ore are found in the mountain Kunjamullay,' near Salem, on the Madras and Beypoor Railway. Fig. io6 illustrates the structure of this mountiun, which rises 2,000 feet above the sea, and 1,000 feet above the surrounding plain. It is an oval-shaped hill, having its longer axis east and west All around the hill three principal beds of magnetic iron ore crop out These beds are each

about 50 feet thick, and there are some minor ones nearer the summit about zo feet thick. The strata are probably of Laurentian or Cambrian age. The ore is of good quality, resembling those of the deposits of Sweden and Norway.

In the vicinity of Chandywick, in the Nerbudda Valley, in Central India, iron ore is found in iiregular beds that consist of loose lumps of haematite, partly decomposed, that lie In hollows of the surface, and which reach a depth of ten or eleven feet These beds seem to have been derived from veins of the same material that occur in the neighbourhood, only in an undecomposed state. One of these was formerly worked by the

' KingindFoote. 'Geological StnictureofPaitsofMadnw,' Gteltgiral Magtuini, 1865, p. 173.

Tron Ores Of Russia And Austro-Hungary. 255

natives, near Manera It is from two to ten feet thick, of rich specular iron, with very little admixture of earthy matter.

In the Himalayas, and North-West India generally, iron ores occur in day slate, probably of Cambro-Silurian age, and in colour green, glossy blue, and mottled blue and brown. The ores lie in thin interstratified beds, that thicken out occasionally, and also in masses and lumps of ore. The district of Dhuniakote contained formerly seven or eight iron mines, which were rudely worked. The deposits here and elsewhere, as well as those associated with the Coal-measures in India, remain for European energy.

The ores are haematite, compact brown iron ore, and more rarely specular iron ore.

The slaty rocks become calcareous towards the top, and are surmounted by limestone. In both the calcareous slate and the limestone, there are numerous fissures and irregular cavities, which are lined and sometimes led with the varieties of ore just named. At the junction of the rivers Rhuma and Kosila, bands of quartz containing similar deposits are interbedded in the group.

Russia. — Considerable quantities of iron ore are raised in this country ; the production of metallic iron in the year 1874 is given as: Ural, 1,017,000 poods, with 69,000 poods of steel; Moscow, 1,830,000 poods; South Russia, 440,000 poods ; and Poland, 800,000 poods, making a total of 3,813,000 poods, or — the pood being equal to 36 English pounds— 61,284 tons. The total production of iron in Russia in 1878 was given at 320,000 tons a year; but possibly this amount is exaggerated.

AusTRO- Hungary. — We have already seen how largely iron ores are mixed up with other metallic ores in the mines of Hungary and the south-east of the empire, and the total production of iron in the empire is given for 1877 at 554,966 tons. In the north-west spathic iron ore — carbonate of iron — is abundantly mixed up with tlie lead ores of the Erzgebirge and the mountains to the south.

Germany. — The last remark is also true of the silver-lead mines on the Saxon side of the range, and proceeding north-west

256 Metalliferous Minerals And Mining.

we reach the more distinctively iron-mining State of Nassau. The annual production of iron ore in this rich little mining State amounts to nearly 200,000 tons. The iron ore deposits of this State are interesting because much of the ore is found in different geological position to any others. Fig. 107 will show the general position of these ores. They lie in hollows and abraded surfaces of the porphyritic rock, 4, and are somewhat irregular in their occurrence, so that the mining for them must be of the simplest and cheapest kind. Iron ores are also found in irregular deposits, in the limestones, and in stratified beds in the older rocks.

When Devonian limestones rest on the porphyritic rock, as they do in a large portion of the State, accretions of phos-

FiG. X07.— Sbction op Ironstone Minb at Obbrnbissbn, near Dibz, Nassau. X, Gravel and day. a. Red iroDstone. 3, Brown ironstone. 4, Porphyritic rock.

phate of lime' and irregular beds of manganese, which are worked near Staffel, Weilburg, and Heckolshausen, rest similarly near the base of the driftal clay.

Prussia, Brunswick, Hanover, and Wttrtemberg are also iron-producing States ; and the present aggregate annual production of iron in the whole German empire may be taken at about 360,000 tons. The production of iron ore in Prussia in 1879 was 2,955,872 tons ; this quantity being raised from 549 pitSy employing 21,991 hands.

Sweden and Norway. — The strata of these north-west countries of Europe consist of a succession of granitic and gneissic rocks, surmounted by slaty rocks in all stages of metamorphism

Odernheimer, Berg und ffuttenwesen im ffertogthum Nassau. D. C Davies, 'Phosphatic Deposits of the Duchy of Nassan,* GmI. Mag,, 1868.

Iron Ore Deposits Of Sweden And Norway. 257

and contortion. The l&miiue, or thin beds of the gneissic rocks, show numerous variations of the prevailing constituents — quartz, mica, felspar, and hornblende — and the whole series here, as elsewhere, is penetrated and disturbed by intrudve granites and greenstones. The strata belong to die Laurentian and Lower Cambrian groups, possibly to that of the former alone. The iron ores occurring in them may be divided into three classes : i. Deposits of pure magnetic oxide which usually occur in granite and gneiss, and also in the accompanying talcose, chloritic, and micaceous slates, and in the interstratified homblendic rocks ; 3. Specular iron ore, sometimes pure and sometimes mixed with magnetic iron, which occurs in similar rocks to those just described ; and, 3. Magnetic oxide, which is generally found in argillaceous slate higher in the series of strata. We may now select a few examples of particular

The magnetic oxide is found in a very pure state at Kspbeig. It occurs as a lenticular mass, the longest axis td which coinddes with the dip of the slate beds in which it lies.

At Danemora, 55 miles fiom Stockhohn, a similar deposit occurs in a femiginous bed of slate. It extends 7,000 feet long, and 600 feet wide by ao feet thick, and it has been worked downwards about 700 feet. The beds being highly inclined, these and similar deposits assume a roughly flattened cylindrical fis. isb.— ducuh SunroH shape, with their widest """ "

base downwards, as ccr. DapiMiuofiuciiKicirc

shown in Gg. 108.

At Uto the ore is a specular oxide, mixed with magnetite. The deposits take the form just described, fig. to8. They lie in quaitzose and micaceous strata, quartz prevailing close to

358 Metalliferous Minerals And Mining.

the deposit The principal deposit is 150 feet across its widest part Its axis is vertical

Where, owing to denuding forces, the surrounding strata have been broken and washed away, these great masses of ore assume the shape and character of ore mountains. A notable example occurs in the ore mass of Gellivara, Sweden, latitude 67 The mass is between three and four miles long, by half a mile wide, and consists for the most part of masses of specular ore, mixed with magnetic The principal deposit of the hill is zoo to 500 feet thick, and is made up of a central mass of specular ore, surrounded by haematites. The ores from these mines contain the largest amount of phosphorus, 1*62 per cent

Near Gellivara are the Kirunavara and Guossavara Mines, in which is a mass of ore 1 1,000 feet long and 500 feet across.

At Hassel, in Norway, specular ore is interstratified with slaty beds, or rather the latter are impregnated with ore to the extent of 30 or 40 per cent At Taberg, in Smaland, beds of oie have been found in eruptive rock.

The whole of the deposits described, and others of which tbeff are the examples, frequently occur in a series of parallel lenticular masses, as described, which extend over laige belts of country.

The iron ores of Norway and Sweden are for the most part valuable especially for the manufacture of the finer kinds of iron and steeL Analyses made from 28 districts show ores ranging from 30 to 71 per cent of iron, the working average being 50. The amount of alumina in them is very smalL Some of the magnetic ores have enough of lime and magnesia in them to do without a flux, particularly those from Danemora and Grangesberg. Phosphorus is present in small quantities in most of the ores, reaching its maximum of 1*62, as we have seen in the ores of Gellivara. Where calcareous matter is preset in the strata, there is a greater variety of minerals in the iron ore deposits.

The principal deposits worked — Perseberg, Norberg, Giangesbeig and Danemora— extend in a north-easterly direc-

Iron Ores Of Belgium And France. 259

tion from the northern end. of Lake Wener to the Gulf of Bothnia. The important deposits of Gellivara lie, as already described) in the extreme north of the coimtry.

Bog ores, consisting of the hydrated peroxide of iron, are fowid in the southern parts of Sweden* They are found in bed which sometimes reach two feet in thickness. These ores contain much phosphorus, hence they are not adapted for the manu* &cture of malleable iron, but receiving from the phosphoras greater fluidity when smelted, they are well adapted for the finer kind of castings for which they are used. One reason why the iron ore deposits of these countries have not been more extensively worked, is the inaccessibility of many of them ; secondly, the want of cheap means of transportation and of fuel to melt the ores on the spot; and, thirdly, men of limited means have preferred to work their little concerns separately, instead of combining for common expenses

In 1874 the total amount of haematite and magnetic ore raised from 696 mines was 807,887 tons, besides 4,601 tons of bog and lake ore.

Belgium.— Returning southwards, we find a good deal of iron ore raised from the Coal-measures, the coal of which id very good for smelting, and the Belgians try to make the best use of everything.

France.* — In the upper part of the Valley of the Moselle, about Nancy, there is considerable deposit of ironstone as a bed in the upper part of the Lias, or at the base of the Oolitic formation. The bed seems to occupy the horizon of the Northamptonshire ironstones, as shown in fig. 113. The bed is interstratified with marl, and varies in thickness firom a to 36 yards. The ore occurs in small grains, cemented together by lime and clay. The ores are described as oxydated hydrate ores, with occasional traces of pyrites and phosphorus up to I per cent The proportion of metallic iron ranges from ao to

' See Engitueriftg ami Mimng ymmal of New VcrJk, vol. zziy. p. 149 ; Whitney's MtaUfc IVialth.

Cailloux, Mines et Afineraux de la Fnuice; Jordan, Mining Jbumai Septemlcrai, 1878, page 1036.

sa

260 Metalliferous Minerals And Mining.

35 per cent An important bed of red haematite occupies the same geological horizon near the towns of Privas and Voulte, in the department of the Ardche. The ore varies in structure from a shaly and grain-like haematite, with 30 per cent of iron, to a solid, agate-like texture, containing 50 per cent

The bulk of the iron ores used in France are, however, derived from the six great coal districts of the country ; but the ironstone beds do not attain the thickness or importance of the English ironstones from the same source.

Then, in the departments of Isbre, of the Pyrenees Orientales, spathic and magnetic ores and haematites are found in the older strata, like those of Norway and Sweden, although, from the want of means of transit, these have not been worked to any considerable extent

Spain. — The mention of the Pyrenees leads us to the rich deposits of iron ore so extensively wrought in the north-west portion of this country in similar and in oolitic strata. The mines of Biscay lie some 15 or 20 miles from the port of Bilbao, which, as far as trade is concerned, has been created by the iron mines. The port or ports have several piers several hundred feet long, from which vessels up to 1,600 tons burden are loaded. Some idea of the extent of the trade done may be formed from the fact that, in one day of the present year, at one of the piers, 636 trucks of ore, amounting to 3,365 tons, were discharged into the vessels lying alongside. One of the companies, the Galdames, employ 1,150 persons on their railway, pier, and mines. The mines consist of open excavations and of levels driven in the side of a mountain. The ore is red haematite, ranging 50 to 60 per cent The production of this company is now 200,000 tons a year.

Above these mines are those of Orcanera and Triano, which are also huge excavations in beds of ore, as well as excavations undeigroimd. These mines produce about 1,200 tons a day, of about the same percentage as that just given. The mines belonging to Herr Krupp produce 200,000 tons yearly.

See ' The Mines of Biscay/ MimH JourtuU September 21, 1878.

Iron Ore In Algeria. 26 1

The production of the whole of the mines of this region is very great, probably not less than 3,000,000 tons. Some of the mines seem to have been worked from the time of the Romans, but it is only of late years that the works have attained their present great dimensions. Iron ores are also derived to a limited extent from the Coal-measures Worked in Spain.

Algeria — Crossing the Mediterranean into Algeria, we find an important deposit of iron ore in the older rocks of Moktael tiadid, thirty kilometres from Bona, on the borders of Lake Telgara.

The deposit is a bed about five yards thick, the outcrop of which forms a curved line along the face of the hills for a mile and a half in length. It dips at an angle of thirty degrees S£. and lies between a bed of erica schist below and limestone above. It yields 65 per cent of iron. The deposit was begun to be worked in 1840. The overlying rock is taken off, and the bed is worked in steps or galleries. The yield in 1874 was 430,000 tons, which was shipped at Bona.

Chapter Xxix.

IRON—comiinued,

Iitm Ore DqnmtB of the British Isles — Cornwall — Devon — West of Irclanil— -Forest of Dean — Lancashire and Cumberland — Iron Ores of the Coalmeas1es— Divisions of the Coal-measures, and Iron Ores of each Division— Iron Ores of the Liassic and Oolitic Strata— Of Yorkshire, Lincolnshire, and Northamptonshire.

Great Britain and Ireland. — The British Isles are the largest producers of iron ore of any country in the world. The production in 1877 reached a total of 16,693,802 tons. Of this amount about 12,000 tons were from the older rocks of Devon and Cornwall ; and the counties of Antrim, Donegal, and Londonderry, in Ireland, gave about 150,000 tons from the newer rocks of the N£. coast. About 2,500,000 tons were derived from the Carboniferous limestones of Somerset, Gloucester, Lancashire, and Cumberland ; 6,000,000 tons from the Coal-measures, and 7,500,000 tons from the Lias and Oolites of Lincoln, Northampton, and Yorkshire. In 1878 the amount produced from all sources was 26,473,597 tons. I will describe each of the sources whence the iron is derived, beginning with the oldest

Ironstone mining in Cornwall is of recent date. The principal mines, of which there were nine producing ore in 1877, are near the towns of Lostwithiel, Wadebridge, and in the parishes of Roche, St. Stephen's, and Ladoc. The mines of Lostwithiel were first opened in 1829. The ore of the county is a brown haematite, and its value last year was under lox. per ton. The ore occurs in beds, more or less irregular, that lie between the strata of the older rocks.

In Devonshire there are four mines producing iron ore. The

Haytor Iron Mine, Devonshire. 263

two principal ones are Florence, yielding in 1877 3,611 tons of brown hsematite, and Haytor, yielding 2,611 tons of magnetic oxide. This mine is worked on the eastern borders of Dartmoor. It occurs in three distinct beds, as shown in fig. 109 (from Foster), which are interstratified with beds of shale and sandstone, said to be of Carboniferous age, but which, for the reasons I have already adduced, may belong to an older group. Near the beds of iron ore, hornblende enters largely into the composition of the enclosing rock, which is also sometimes made up almost entirely of actinolite. The beds are ochreous near the surface, and they have been worked for ochre. They are traceable & and W. for a distance of three quarters of a mile. They dip at an angle of 30 drees to the north. Dr.

Fig. S09.— Sbcttom in tux Hattos Minb.

Scale i"aB40 feet.

m, SiUdoos date and Actmolite rock. MaiCDetic ma on. c, Gnaite veto.

Foster thinks that these beds were deposited something like the Cleveland beds, and that they have subsequently been altered into magnetite by heat

Forest op Dean. — The Coal-measures of this small insulated coalfield are underlaid here, as elsewhere, by a series of sandstones known as Millstone grit, which is here of great thickness. In its cracks, permeating its softer strata, filling up joints and cavities, and lying in beds, lie the uppermost signs of the ores that have made the Forest of Dean a great iron-producing centre. The principal deposits ' lie below the base of the Millstone grit, and in the upper part of the main mass of the mountain or Carboniferous limestone, and in this position diey crop up around the edge of the coal basin, and in all probability, judging from the distance from the edge to which the

Dr. Foster, Quarterly Jcumal GeologUal Society vol. xxxi. ' See Dr. W. WatioD, Ctoh, 185S.

264 Metailiferous Minerals And Mining.

deposits have been worked, they lie under the whole area of this coalfield. The exact position of the deposits is shown in fig. no.

The Whitehead limestone, i, is 40 yards thick. It consists of red and purple sandy shales, passing upwards into the Millstone grit.

The black rock, 3, is made up of limestone, calcareous shales, and the Foreline, which passes downwards into the Old Red Sandstone.

The grey ironstone formation, 2, in which the principal iron ore deposit occurs, consists of one bed or mass of cavernous limestone, of an average thickness of 25 yards. The ore deposits within it are not evenly continuous, but occur in large masses that fill up cavities or chums ' in the limestone, and which are connected with each other by 'leaders* or strings. The limestone is called crease,' and it is traversed by innumerable small

Fig. xza—DiAGKAM op thb Ironstohb Pockets in the Foxbst op Dsak.

X. Lowest bed of White Head limestone, called lidstone. 9, Mine measiire<( in limestone, yards thick. 3. Top of Foreline or Mountain limestone, wludh contains veins filled witii ore, running NE. and SW.

joints that do not seem to follow any regular order. Leading joints ascend firom the ' chums ' into the overlying Whitehead limestone, and through the rocks above it to the daylight

The ' chums ' are near to each other, so that when the limestone in which they occur is reached, the mining for iron is not uncertain or precarious. One of these chums was 350 yards long, 14 3rards high, and 12 yards broad, and is estimated to have yielded 60,000 tons of ore.

The ores are divided into : first, brash ; ' second, Smith Mine ; ' and third, clod.' The brash ore is a haematite, often yielding 80 per cent, of metallic iron, the compact kidneyshaped ore having a partly metallic lustre and a fibrous stracture. It is fi:equently stalactitical and covered with brilliant black

Varieties Of The Forest Of Dean Iron Ores. 265

oystals of hydious-oxide of iron. The Smith Mine is a. finely powdered peroxide of iron, very free from extraneous matter. It contains from 54 to 58 per cent of iron. The clod is a marl, charged with peroxide of iron and with small fragments of haematite or brush ore.

The roofs of the chums are usually encrusted with stalactitic ore ; concretions of compact tucmatite, coated with shining ciystals of hydrous iron, lie against the walls of the chums, while

Tub DnfiL'i Chahi, Oio Pawc Imn Uinu, huh Buah, Foinr Diah. I, A ludK. I, Vawctkai on. j, A drift. 4, Opauu Bad* on k IeuL

the interior of the latter are filled with powdery hsmatite,' which is held together by a slender framework of harder ore. For the most part the ores yield readily to the pick, so that they are cheaply mined. In the limestone, by which the chums are separated from each other, geodes, or large irregular balls of haematite, are common. So fiir the chums of ore have been found largest and most productive around the maigin of the

266 Hetaixiferous Minerals And Mining.

coalfield. The miners hAve a saving, 'The smaller the leader the larger the chutiL' Fig. iii, adapted from Watson, shows a section of one of the most remarkable of these churns, known as The Devil's Chapel,' at the Old Park Iron Mines, near Bream.

There are some ironstone deposits, known as the ' sandstone vein,' in the Millstone grit, some distance above the deposits just described. Its ore is rich in quality, but the chums are not of great magnitude, the thickness of the bed being only about five feet

In 1877 33 mines yielded 93,974 tons of ore, of the value of 93,361;, or about 13. "jd. per ton.

Latucukire and CvmierlaiuL — Great deposits of ironstone

are found in the Carboniferous Hmestonc of these counties, which partake lately of the character of those just described from the Forest of Dean. The deposits are of irregular dimensions, and fill up cracks, joints, cavities, soft beds, and inequalities in the upper portion of the limestone.'

Fig. 113 illustrates a common mode of the occurrence of the deposits. Sotroidal forms of the ore, accompanied by crystallised calcareous minerals, are also formed in cavities. The ore also occupies cavernous spaces in the limestone, and the fossils of the limestone beds are converted into hsematite, chiefly clayey ore. The ores are kematite of different kinds ; they yield about 60 per cent ef oxide of iron, 5 to 6 per cent ' J. D. KendBll, Q. J. Ctolegical Stciity, No. 136.

HiEMATITE ORES OF THE NORTH Oy ENGLAND. 26/

of silica, with varying proportions of alumina, lime, magnesia, and occasionally manganese. The beds of ironstone, like that in fig. 112, may represent original deposits of feiruginous mud on the sea bottom, while the chums of the Forest of Dean, and the cavities fiUed with iron ore in these northern limestones, seem to point to a subsequent filling by an infiltration of water passing through overlymg ferruginous beds, as the deep red beds of the Permian, or the ironstone beds of the Coal-measures.

The older rocks of the district are largely charged with iron. A great piece of rock on the south side of Ennerdale Lake being called ' Iron Crag.' Ore in small quantities is obtained from these sources.

Then similar deposits to those worked in the Carboniferous limestone also occur, and are worked in the older Silurian limestones, as at Waterblean Mines in Cumberland. Here the strata are vertical, and water charged with iron seems to have penetrated and permeated the soft partings between the limestone beds.

The production of iron ore in the two counties for 1877 was 2,344,454 tons, of the value of 1,616,478/., or about ly. gd, per ton.

Iron Ores of the Coal-measures} — Usually these ores are separated in statistics from those derived from other geological formations. As, however, quite one-third of the total production of the British Isles is derived from this source, this book would not be complete without at least a brief notice of the ironstone deposits of the Goal-measures. The ores lie in regularly stratified beds or layers in the midst of the clays and shales that lie between the coal seams. Usually the iron — which seems to have been held largely in solution in the water in which these beds were deposited — has accumulated itself around some organic substance, or it fills the place once occupied by Carboniferous plants or organisms, the original material of which has perished. I divide the Coal- measures into four chief parts, in descending order, thus :

See Tki Iron Ores of Gnai Briiain: publications of the Geological Survey.

268 Metalliferous Minerals And Mining.

1. The Upper Coal-measures, extending from the Spirorbis limestone down to the sandstones and thin coals represented in South Wales by Pennant grits.

2. The Middle Sandstones and Coals. Pennant sandstones of the South Wales, Forest of Dean, and Bristol coalfields, and their equivalents elsewhere.

3. The Lower and Productive Coal-measures.

4. The Lowest or Gannister series.

Now in the whole series of the Coal-measures there are three productive and well defined horizons of iron ores. These are, in descending order :

1. The Black Band ironstone of Staffordshire, Lancashire, and Scotland, which lies near the summit of group i, or the Upper Coal-measures. Probably its equivalent in Shropshire and South Staffordshire is the Chance Pennystone. Its ores are, where worked, a carbonate of iron, which enclose and take the place of fish and reptilian remains. It is valued as an ore of iron.

2. The clusters of ironstone beds which lie in group 3, the productive Coal-measures below the Thick coal of South Stafford, and its equivalent in the other coalfields. To this series belong the productive and extensively worked New or White mines of Stafford and Warwick, and the seams that in North Wales lie between the Main and Lower yard coals.

3. The series of ironstone beds that lie in group 4, or the Gannister series, and of which the Rosser and Pennant seams of South Wales, the Blue Flats of South Stafford, and the eleven beds that lie above the Halfyard coal in North Wales, may be taken as examples.

The ores firom the two last groups are known as clayey 01 argillaceous ores, the percentage of iron in them ranging from 20 to 35 per cent. The ironstones of the Coal-measures of Ireland are said to be much purer than those of England, and to contain 47 per cent of metallic iron ; but they have not been much worked hitherto.

There are also associated with the coal seams bands of iron pyrites, which, when not found mixed with calcareous matter,

The Iron Ores Of Cleveland. 269

are used for the manufacture of sulphuric acid. The average value of the ores raised in 1877 in Great Britain from the Coalmeasures was as nearly as possible 12s. per ton.

TAe Iron Ores of the Liassic and Oolitic strata, — I now pass on to notice the recently discovered deposits of iron ore in the Jurassic strata, as the two geological formations just named are called, the value and importance of which have so largely increased the iron industry and the wealth of the counties of Yorkshire, Northamptonshire, and Lincolnshire. The section, fig. 113, represents to scale the general order of the Jurassic strata of England, and shows the relative position of the iron ore beds in the three counties I have just named.

The Iron Ores of Cleveland Yorkshire. — I will begin the description of the ore beds represented in the section by a notice of those worked in the Cleveland district, Yorkshire.

This comparatively modem iron ore producing district occupies the north-east portion of the county, having the sea on the east, and the River Tees on its north boundary.

The lowest and principal bed of ironstones occurs, as shown in the section, fig. 1 13, in the marls that divide the Upper from the Lower Lias. The rock underlying it is a fine-grained, dark blue rock.

The ironstone deposits themselves consist of a varying number of seams which are interstratified with shale which is usually of a blue colour. For example : At Skelton there are four seams, which, with the accompanying shale, make up a thickness of 17 feet 7 inches ; at Kildale there are seven, with shales 18 feet inches ; and at Grosmont thirteen, with the shales making up a total thickness of 69 feet 2 indies.

Most of the nodules and fragments of iron ore take the place of the organic matter of fossil remains. Thus the lowest of the seams in the ' Main ' deposit is known as the ' Avicula ' seam, from the abundance in it of the fossil shell of that name. Higher up is the ' Pecten ' seam, in which the workings are chiefly conducted. Above this is the ' Sulphur Band,' which is parted by a thin bed of shale from th overlying

Bewick, Theatise M tAe Cleveiand fromtoftes, 1861.

270 Metalliferous Minerals And Mining.

Dogger Band/ a seam that varies in thickness from 1 1 inches to 3 feet

upper

Sandttones, Yorkshire

Collywestoo slates, NoithampcoBihire

Limestones and clays, Tiincofnshire

Top seam, Yorkshire Northamptonshire ironstones Maristone seam. Tinrolnshire

Dogger and jat rode, Capricomis beds, LanoolnsUre Upper Lias day,

V Main Pectsn

of ironstone, Ckvelaiid , Liaooinshire .

Marls and UmMtones

Place of the Lincohishire ironstones Limestones and days

Pic X13.— Sbction or thb Jurassic Strata op England, showing thb Posmoif OP THB Iron Orbs op Yorksmirb, Northamptokshirb, and Lincolnshirb.

Scale x"szoo feet about.

This Main ' deposit is thickest along the northern boundary of the district. Starting on the north-east coast line the beds

THE IRONSTONE BANDS OF CLEVELAND. 2Jl

are thiimest between the Peak and Whitby. From this point to Boulby there is a great aggregate thiduiess of ironstone beds, but they are widely separated by shale. North of Boulby the seams begin to coalesce ; they present a more compact mass at Skinning Grove, and reach their thickest and best condition about the Eston Hills, where they are i8 feet thick Following the western boundary southward from this point there is a similar decrease of thickness to that observed on the east coast boundary ; until at Kildale the deposits split up by partings of shale, so that the thickest portion is not more than 3 feet thicL The Pecten and Avicula seams, which are sometimes 20 feet apart, come together in the region about Hutton and Grosmont At the latter place they make a combined thickness of about 14 feet, only 6 feet 6 inches of the Pecten seam being workable. Besides the fossil shells just named, numerous terebratula are found, throughout the whole deposit, which are converted into ironstone. At Normanby mines the deposit shows the following section :

ft. in.

1. Top block of ironstoae-Dogger . . 2 6 left to support the roof.

2. Pyrites band 02 „

3. Main block of ironstone, including

Pecten seam 80

4. Bottom block of ironstone, Avicula seam o 9

Total thickness . . .11$

Working beds.

About 200 feet above this Main deposit is the Top Seam. It is situated, as seen in fig. 113, at the top of the Lias, forming a boundary between it and the overlying Oolite. It varies in thickness from i to 20 feet, and, unlike the Main Seam, it generally thickens from north to south, where it attains its maximum thickness. Its general appearance is that of a coarse, hard, silicious ore, of poor quality, ranging from 15 to 20 per cent of iron. Here and there it contains nests of fossil , which are richer in iron, yielding from 30 to 36 per cent Near Rosedale Abbey it passes into a magnetic ore, although the identity of this particular deposit with the Top Seam is sometimes questioned. Successful workings have been carried on in this seam near Henderwell, on the coast, but for

2/2 Metalliferous Minerals And Mining.

the most part the profitable workings are confined to the Main SeanL The ores of the two seams are usually described as argillaceous carbonates, and the following are analyses of medium examples of the ore in each seam :

1. Analyses of twelve samples firom the Top Seam at Beckhole :

Clay . 20*00

Peroxide of iron 51*00

Almnina 6xx>

lime 2*92

Magnesia , 19*00

98*92 Equal to metallic iron SS'OO

2. Analyses of sample firom the midst of the Pecten Seam of the Main Block at the Eston Mines :

Water in combination 4*70

Phosphoric acid 2*49

Carbonic acid . 26*16

Magnesia ,.,. 3*19

Alumina 12*66

Silica 6*00

Peroxide of iron 3 "95

Protoxide of iron 40*85

The amount of ore raised has been nearly the same during the last three years. In 1877 it amounted to 6,284,545 tons, of the value of 1,021,238! iis.y or at the low price of about y, d. per ton. The ore was produced from 33 mines.

Lincolnshire, — More recent is the discovery made some sixteen years ago of the ironstone bed of the NW. comer of Lincolnshire, and its introduction to commerce by Mr. R. Winn, M.P. By a reference to fig. 113 it will be seen that the Lincolnshire ironstone bed lies lower in the series of strata than the Main deposit of Cleveland. It is about 27 feet in thickness, and it abounds in Liassic fossils, — ammonites of the keeled varieties, together with an abundance of cardiums

' Rey. J. Cross, QuarUrly Journal Geological Society vol. xxxi, page 115, eiseq.

The Iron Ore Beds Of Lincolnshire. 273

which are filled with calcite and are beautifully transparent. The base of the bed is a hard limestone band, and similar bands are intercalated with the bed and contain the fossils. Between these limestone beds are soft ferruginous beds of a dark brown* colour and rubbly texture, which also contain a good proportion of brown dust. They contain but little silica, but abound in lime — rather too much so ; but ores containing silica are obtained and mixed with these in the proportion of one part to eight. tons of the ore yield i ton of metallic iron, giving an average of about 28 per cent

It will be seen that above this principal bed there is a thin band of ironstone known as the Pecten bed. ]t is a rocky band, 4 feet thick, crowded with pectens. Higher up still there is another band of ironstone known as marlstone. Although neither of these two are much if at all worked, they are interesting as appearing to be on the horizon of the Main Seam of Cleveland.

The ores are termed hydrated oxides, and last year two mines produced 508,750 tons, of the value of 76,192/., or nearly $s, per ton.

Northamptonshire, — This is an older iron-producing county.

Its ironstones, as will be seen by the section fig. 113, appear to

occupy the place of the top ironstone bed of Cleveland. At

Burghley Park Ironstone Quarry the section of the deposit

stands dius : '

Top, Collyweston slate.

ft. in.

Sand passing downwards into blue clay . 6 6

' Best black ' ironstone, cellular . . . 20

Second black ironstone, less cellular and more sandy 2 o

Calcareous band 06

Bottom ironstone, cellular 20

Green ferruginous stone 16

Thin ferruginous band 09

Upper Lias clay.

' Oolites of Northampton,' S. Sharpe, Quarterly Journal Geological Society vol. xxix.

T

274 Metalliferous Minerals And Mining.

The ironstone beds appear in their thickest and richest condition at Woodford, Cranford, Wellingborough, and the neighbourhood.

In 1877 26 mines produced 1,049,806 tons, of the value of 169,981/., or nearly 3. $d. per ton.

Of an important character commercially are the iron ore deposits of the NE. of Ireland referred to. They occur between a basaltic bed above and altered limestone below, which is taken by some to be of oolitic age and by others as belonging to the older tertiary strata. It skirts the NK coast for a length of 70 miles. The ores are chiefly aluminous ores and haematites, which lie in a bed in the following order :

Name

Thickness

Percentage of metallic iron

Pisolite

2 feet

So

Bole

8 „

fiottom, Lithomarge .

The beds are not always distinct, but merge into each other, and from the whole the ores are made into an average containing 40 per cent of metallic iron. The ores are free from phosphorus, and the presence of alumina acts as a flux. They are largely exported to Lancashire, Cumberland, and South Wales, for admixture with other ores.

27S

Chapter Xxx.

JRON—cotUinuid,

Ores of the Dominion of Canada — Nova Scotia — The United States. Eastern States — Missouri — Michigan and Lake Superior — Of Australasia— General Deductions.

The Dominion of Canada.' — The iron ores of the Dominion, especially those of Nova Scotia, are increasing in importance. Those of Nova Scotia are classified as follows : —

Geological fonnation

Recent

Traps and dykes inf

Triassic sandstones t

Coal-measures

Carboniferous stone

Devonian .

Silurian!

Cambro-Silurian Cambrian

lime-

and f

Nature of otm

Bog ores

Red haematite and magnetite

Clay ironstones .

Clay ironstones with red haematite, spathic iron, and limonite

Specular and magnetic ores .

Red hsematites, specular and magnetic ores

Titaniferous and specular ores

Locality

Bloomfield

I Bay of Fundy

Pictou Coalfield

French Pictou

I Clement's Port, I near Annapolis ) Londonderry, Pic-

iSt. Mar/s Bay, ) Digby

The Bloomfield bog ore occurs in layers of six inches to one foot thick, covered by a few inches of soil. It yields 25 per cent of iron. It is used for mixing with other ores.

Dykes and masses of trap penetrate and are interstratified

' Hartington, in Report of Progress of Geological Survey of Canada, 1873-4; Gilpin, Transactions North of England Mining and Mechanical Engineers, vol. xxvi.

T3

276 Metalliferous Minerals And Mining.

with the Triassic sandstones of the Bay of Fundy, and intersecting these are numerous veins and pockets of red haematite and magnetic ores, not exceeding a foot thick. The magnetite is also finely disseminated throughout the trap, from which, when powdered, it can be separated with a magnet Two analyses of these ores give : metallic iron 69 ; oxygen 25 ; silica 5, with traces of lime and magnesia.

Little attention has hitherto been paid to the clay ironstones of the Coal-measures.

In the Carboniferous limestone of Sutherlands Brook and French River, Pictou, there is a large deposit of spathic ore. It is a sparry carbonate of iron. It consists of three beds, which dip south at an angle of 60°. The lower and upper beds are from 6 to 10 inches thick, and the middle *main' bed is from 6 feet to 10 feet thick. Where protected from the weather, the ore is of a grey colour with a pearly lustre. It contains 20 per cent of sesquioxide, and 57 per cent of carbonate of iron, yielding 42 per cent of metallic iron, and it is free from phosphorus.

In the Silurian strata of Londonderry, at a distance of from 1,200 to 1,500 feet below the Carboniferous strata, is an important bed of limonite, or brown iron ore. It occurs in a mass of dolomitic limestone, 30 to 150 feet thick, which also contains layers of breccia, quartzites, and slates. These are traversed by veins of from 5 to 50 feet wide, in which the ore occurs in compact stalactitic and botryoidal masses, associated sometimes with micaceous haematite.

Titaniferous iron ore is found as sand in irregular beds at St. Mary's Bay, west of Digby. At Bay St Paul, on the north shore of the Gulf of St Lawrence, is a bed of titanic iron ore, about 90 feet thick. The ore consists of 36 per cent of iron and 44 per cent, of titanic acid. It is described as free from manganese, sulphur, and phosphorus.

The geological survey of Canada reveals as it progresses similar deposits of iron ore right away into British Columbia, which, in time, as the country becomes populated and means of transit are provided, will become available for use.

Iron Beds Of Pilot Knob, Missouri. 2/7

United States. — The deposits just described may be taken as examples of similar deposits that occur at intervals all down the eastern side of the United Slates, and which, although very extensively worked, do not require special description here. There is a newer deposit in Connecticut, to which I may just refer. This is the Ore Hill Mine of Salisbury. It is a vast deposit of ochres, clays, and hematites, of Tertiary age. The ore lies in irregular- shaped masses. It is a fibrous, massive haematite, which yields pig iron of the finest quality.

Missouri. — Proceeding north-west into Missouri we find beds of brown haematite abundantly interstratified with the older Cambrian rocks, and which are largely worked.'

The chief interest, however, gathers around the Iron Mountain and Pilot Knob of Missouri. The first of these is a flat-dome- shaped hill that rises about 200 feet. It is made up of red felspathic porphyry, and forms the western end of a ridge of the same character.

The surface of the hill is covered to a depth of about 15 feet with boulders of all sizes, weighing up to many tons, of nearly pure peroxide of iron. These are closely packed together, with a bright red ferruginous clay filling the interstices. Possibly these iron boulders are the sole remains of an igneous rock, which has been disintegrated and washed away, leaving these, its heaviest portions, behind. The source of these boulders had not recently been found.

Pilot Knob is a higher mountain, rising

650 feet above its base. Fkj. .i4.-SKcnoii or pilot Knob. Miuovdi, Its structure is shown Quutiitiilicioiuroclc 1, Htcmuiu inn bedi. in fig. 114. """W .oommuwr. 3,

The iron beds are wide, but not continuous over a very large area. The purest of them have a somewhat slaty structure, which distinguish them from the ores of Iron Mountain. ' Whitney, Maa:iu Wailth.

278 Metalliferous Minerals And Mining.

Iron Ores of Michigan, near Lake Superior. — This is one of the most important rons for iron ore in the Uniied States. The deposits occur as a vast succession of thin beds in the slaty and homblendic rocks — 3 b of the section, fig. 58, Chapter xviii. The intimate relationship of the beds to the adjacent strata is seen in fig. 115.

These ferruginous siates form a belt, varying from six to twenty mDes wide, and stand out as successive cliffs of from 50 to 150 feet high, and which really seem mountains of iron ore. The belt extends from Lake Superior into Wisconsin, a length of about 150 miles. The highly ferruginous deposits are not continuous over the whole of this length, but occur at intervals

in areas extending from a few hundred yards to over a mile long.

Generally speaking, the deposits consist of peroxide of iron, mixed with much silicious matter. They occur as thin alternating beds, the iron at times consolidating and forming beds of great thickness. These beds are traversed by joints that cut the ore into square blocks.

In one mine the deposit shows the varieties of structure enumerated, having in the centre the laminated structure, and passing on each side into compact ore of great purity. In its purest state the ore is a compact specular ore, having profusely disseminated through it crystals of magnetic oxide. Some of the deposits are made up of very thin bands, not exceeding a

Production Of Iron In Australasia. 279

quarter of an inch in thickness, of pure fine-grained peroxide of iron and of jaspery ore. On the Cleveland location the deposit is 1,000 feet thick and one mile in length, and it is said that the supply of iron ore here alone is sufficient for the wants of the world for ages.

The iron seems to have been deposited contemporaneously with the material of the slates, and with it has received a rough sort of cleavage, like the ferruginous slates of the Lingula Flags near Tremadoc, North Wales, to which geological horizon it seems referable. Lingulss are abundant in the overlying sandstone.

The average percentage of iron is from 60 to 70, and the ore is said to contain hardly a trace of sulphur, phosphorus, or titanic acid. The deposits were first worked in the year 1855, when the production was 1,457 tons. In 1864 the production had risen to 235,123 tons. In 1877 production of metallic iron was 1,020,859 tons. The total production of pig iron in the United States in 1875 2,266,581 tons.

Australasia. — The production of iron in the various provinces is steadily increasing, and may, at the present time, be estimated at 5,000 tons, in 1875-6 the production being as follows :

Tasmania, 1875 tons of iron.

New South Wales, 1876 . . 2,680 „ Victoria, 1876 5

4,085 tons.

One deposit may be noticed. This is an important deposit that is found as a bed between the Silurian strata and the Coalmeasures of Wallerawang, 105 miles firom Sydney, on the Westem Railway. The deposit is made up of two beds, that contain two principal kinds of ore — magnetite or magnetic oxide, and brown haematite or hydited oxide. The direction of the beds is NE. by SW, The magnetic oxide bed is from 13 to 23 feet thick, and it yields 40 per cent metallic iron, some parts of the bed giving 70 per cent The brown haematite has not been much worked, but it has been proved to a thickness of 20 feet

280 Metalliferous Minerals And Mining.

Some very thick and good beds of ironstone occur in the Coalmeasures of the same district ; and as the coalfields of the continent are opened out, much iron ore will doubtless be derived from this source.

The foregoing description of iron ore deposits afford us illustrations of the principal ways in which the mineral is found all over the world. It will be seen that, happily for man's needs, the ores of iron have both a wider range in time, and a more profusely rich geographical distribution, than any other metallic ore.

As a rule we find the magnetic and spathose ores prevailing in the older rocks, the compact and crystallised haematites in the Carboniferous limestones, and the more clayey and earthy varieties in the overlying formations.

Chapter Xxxi.

Various Metals.

Mercury Ores and Distribution — Bismuth — Nickel — Platinum — Isidium —

Palladium and Tellurium.

Mercury,

Mercury is found in a native form, in combination with silver, and also with other substances, as chlorine, iodine, and sulphur.

Native Mercury, Quicksilver, is of a tin-white colour, and of a bright metallic lustre ; it occurs in a fluid form as globules ; it is very heavy, its specific gravity being 13 '6. It becomes solid and assumes a crystalline form at a temperature of and below 39° F. It is not very abundant in nature, but occurs in most mines where the ores of the metal are obtained.

Native Ama/gapt, — This is a mixture, when pure, of firom 64 to 72 per cent of mercury, with from 28 to 36 per cent, of silver, and it is of a silver-white colour.

Arguerite is a variety of native amalgam, that contains only 13-5 per cent, of silver.

Sulphide of Mercury. — Cinnabar. — Vermilion. — Chemical composition : mercury 86*2, and sulphur 13-8. It is in colour cochineal red, with a lead grey and scarlet red tarnish, and a scarlet red streak This is the ore from which nearly all the mercury of commerce is derived.

Chloride of Mercury. — Calomel. — Horn. — Quicksilver.— Chemical composition : mercury 85, chlorine 15 ; colour, light yellow and grey, and of an adamantine lustre. The rarer ores of mercury are :

282 Metalliferous Minerals And Mining.

Iodic Mercury from Mexico, of a reddish-brown colour, and Selmide of Mercury y a dark steel-grey ore from San Onofie, in Mexico.

China. — In the far East, the Chinese work mines of cinnabar in Shensi, in a rude manner. Pits are dug in the mercurial strata, in which fires of brushwood are made, and metal derived from the surrounding strata by this process is collected after it becomes condensed in the pits.

Austria. — Near Tobria, some distance NE, of the head of the Gulf of Trieste, deposits of cinnabar were discovered in the year 1497, and they have been worked ever since. The deposits occur in the southward continuation of the Erzgebirge and Bohemian mountains, whose structure and metalliferous character have already been described. The ore seems to be contained in the schists of Cambro-Silurian or Cambrian age. The yearly production is about 250 tons.

Spain. — In Spain the chief mines of mercury are those of Almaden, in the province of La Mancha, on the borders of Estramdura. A considerable belt of strata stretches E. and W. from Chillon to Almadenegos, where there are very ancient mines.

The mines of Almaden are opened in three beds that run parallel to each other, apd that lie something like contact deposits between Cambro-Silurian sandstones and slates above, and a metamorphic rock, locally named Fraylesca, below. This rocky Fraylesca, is a sandstone metamorphosed by contact with masses of diorite that underUe and, to some extent, penetrate it The outcrops of some of these masses are seen on the surface not far from the mines. The three mercurial beds make an aggregate thickness of from 25 to 40 feet, and they conform to the flexuosities and stratification of the enclosing rocks. They appear as a black schist. The mercurial vapours seem to have penetrated these beds from below by sublimation, and the ores are accumulated in great masses within them, and also permeate the intervening spaces. The mines are worked to a depth of about 1,000 feet. At this depth the beds are 40 feet thick. The yield of the ore is 10 per cent, and the whole

Ores Of Mercury In America. 283

thickness pays for taking out* The production during the present century has averaged 800 tons a year.

Italy. — At Ripa, in Tuscany, cinnabar is obtained from a cluster of small veins that range through mica slate.

Germany. — Mercury is obtained from the older rocks of Bavaria, of Hartenstein in Saxony, and of the Rhenish provinces, the combined production being estimated at 350 tons.

Sweden. — Mercury is obtained to a small extent in this country, as native amalgam and sulphide.

North America. — In California the ores of mercury were discovered between the years 1840-5, and in 1845 a company was formed to work a deposit of cinnabar, two or three miles up one of the tributary valleys of the San Jose.*

The strata here consist of alternate beds of clayey shale, and layers of flinty rock. The beds are highly inclined and flexuous. The ore lies in intercalated beds of various thicknesses, and in the intervening strata there are strings and bunches of the sulphide of mercury. The strata and the ore seams are traversed by numerous veins of carbonate of lime. The cavities containing the cinnabar are also lined with carbonate of lime, in which there are small globules of bitumen. The ore is associated in a slight degree with the sulphides of iron, copper, and arsenic. Professor Hoffman gave the analysis of the ore from the mines as follows :

Mercury

Sulphur 1073

Silica, alumina, &c 22*55

100*13

At the New Almaden, the principal mine in the district, the prevailing rock is a greenish talcose slaty rock. The ore is disseminated through the slate In a yellow ochreous matrix

La Play, Observations sur rHistoire NaturelU it sur les Rickesses MirUraUs de FEspagru,

' W. P. Black, SillimatCs American Journal of Science (2), p. 438. ' Dana, Mineralogy p. 288.

284 Metalliferous Minerals And Mining.

which forms a bed 42 feet in thickness. The richest ore is from the upper part of the bed. The rock is a metamorphic rock much tilted and contorted, but its exact age h2ls not been ascertained.

Mexico. — In Mexico the ores of mercury are found in several places. At San Juan de la Chica, cinnabar is found in a vein varying in width from 7 feet to 2 feet. . The vein traverses pitchstone porphyry, which has a spherical structure. At Durasno, cinnabar mixed with globules of native metal is found in a bed resting upon porphyry, and surmounted by beds of shaly clay that contains fossil wood and coal.

South America. — Near the villages of Azoqueand Cuenca, in the province of Quito, in New Grenada cinnabar is contained in a quartzose sandstone of great thickness, which also contains fossil wood and bitumen.

Peru, — The principal deposits in this country are those of the province of Huancavelica. Mercurial ores have been found in between forty and fifty places. The ' Great Mine ' of Santa Barbara has been worked since 1566. Through the system of letting, formerly adopted by the government, the mine has been badly worked, and a large portion of the upper and rich workings has long since caved in. The mine presents a series of underground quarries rising in steps one above the other. The strata consist of a series of shales and sandstones about 350 feet in thickness. They lie between other sandstones and conglomerates, and dip west at an angle of 64. The production is estimated at about 900 tons a year. In the alluvial deposits near the mines, about 600 lbs. of native mercury were taken out of a ditch, one to two yards deep, and the alluvium of the neighbourhood seems penetrated with mercury. Ores of mercury are also found under similar conditions in Chili.

From the foregoing remarks it will be seen that ordinarily the geological horizon of the ores of mercury ranges from tlie summit of the Lower Cambrian rocks to the base of the Llandeilo beds of the Cambro-Silurian strata ; that they occur in the midst of eruptive and metamorphic rocks, being mostly

Ores Of Bismuth. 285

associated with greenstone and and that they are frequently accompanied by bituminous matter. Should the strata of San Jose prove of more recent origin it will be seen how very similar are the stratigraphical and petrological conditions to those in which the ores of mercury are found in the older rocks.

Bismuth,

This metal occurs native, and also associated with carbonic acid, oxygen, silica, sulphur, and tellurium.

Native Bismuth. — Of a reddish silver-white colour, and often with red, brown, or yellow tarnish. Fuses at a temperature of 476° F., and is brittle when cold. Specific gravity 9*6 to 9*8. It is used with tin and mercury to form mosaic gold for ornamental purposes, with lead and tin to make toys that easily dissolve in warm liquids. A small portion is usually put into solder required for lead, pewter, and the softer metals, and it is largely employed in the manufacture of printer's type, to give a sharp, well-defined face and edge to the letters. Its ores, which are rare, are :

StUphide of Bismuth. — Chemical composition : bismuth 81, sulphur 187.

Acicular Bismuth, — A sulphide of bismuth, with portions of lead and copper, with a trace of gold

Teiradymite, — A mixture of bismuth and tellurium.

Silicate of Bismuth or Bismuth Blende.

Cupreous Bismuth Wittichite, — Chemical composition: copper 38-5, bismuth 42, and sulphur 19-5.

Bismuthite, — A carbonate of bismuth, with a little sulphate of bismuth.

The chief source of bismuth is in the mines on both sides of the Erzgebirge, where it is abimdandy associated with the ores of silver and cobalt At Schneeberg, in Austria, it is foimd abundantly, and forms tree-like shapes in jasper. It is found associated with copper ores near Drammen in Norway. About 8 cwt was obtained last year from the East Pool Copper and Tin Mine, lUogan, Cornwall It is also found in America at

286 Metalliferous Minerals And Mining.

Lane's Mine, Monro, and at Brewer's Mine, in Chesterfield district, South Carolina. A lode containing the mineral was also discovered in Tasmania in 1875.

Nickel.

Except as forming from 5 to 10 per cent, of meteoric stones, nickel does not occur in a metallic form in nature, unless some masses of native iron which have been discovered in the province of Santa Catarina, in Brazil, are of terrestrial origin. These were found to contain 38 per cent of nickel The metal is produced artificially from its ores. It is hard and ductile, takes a good polish, and is white in colour, with a shade of light grey. Its ores have a specific gravity ranging from 5 to 8. The following are the principal varieties :

Copper Nickel. — Nickeline. — Arsenical Nickei.—CYit' mical composition: nickel 43*6, arsenic 56*4; of a copper-red colour and a metallic lustre.

White Nickel, — Rammelsbergite. — Cloanthite, — Chemical composition : nickel 28, arsenic 72, but often with small proportions of cobalt.

Emerald Nickel. — A carbonate of nickel containing 28*6 of water. In colour, of a bright emerald green.

There are several varieties of the above ores, but as they only consist of slightly proportions of the constituent minerals, they need not be here enumerated.

The whole of these ores are, as we have seen, largely associated with those of lead, copper, silver, and other ores. It is most largely combined with arsenic, and when with this mineral it is eliminated firom the other metals, it is called speiss. It is subsequently treated by various metallurgical processes in order to separate it from the arsenic.

It is a useful metal. Alloyed in the proportion of 3 parts nickel, 8 of copper, and of zinc, it constitutes German silver, which is whitest and hardest, as it contains the largest proportion, of nickel.

In AusTRO-HuNGARY it is associated with the ores raised in the various mining districts already described. In Germany

Nickel Ores In America And New Caledonia. 28/

it abounds among the ores of the Eizgebirge, the production being about loo tons annually. In SiUsian Poland there is a production of 3 or 4 tons annually.

In Spain a silicate of nickel, free from cobalt, antimony, and arsenic, is found near Malagar, which contains a percentage of 3*96 of nickel.

In Norway a mine was worked at Espectalen formerly, from which, in two years, about 1854, 370 tons of ore were sent to England.

In Great Britain nickel is found associated with iron at Voel Hiradig, Cwm, in Flintshire. Since 1870, 675 tons 14 cwt of nickel iron ore have been raised on this mountain, of the value of 3,691/., or about 5/. lor. per ton. The average proportion of nickel was 2 3.

North America. — Canada, — Nickel is found in a deposit that lies along the bedding between serpentine rock below, and a magnesian limestone above, in the township of Oxford, and province of Quebec, Canada. The strata are referred by Dr. T. Sterry Hunt to the Huronian strata, the equivalent of our Cambrian group. The deposit is about 9 inches thick, and it is filled with calcite containing grains and crystals of the sulphide of nickel. There is also a good deal of chromite and chrome garnets. Grains of the nickel ore cluster on the hanging wall of the deposit, or bed, as it really seems to be. Some of the crystals are of great size and beauty, being an inch long. The proportion of nickel to the mass of the ore is from 3 to 4 per cent

In Connecticut nickel is found near Chatham. The veins in which it occurs traverse mica slate. The proportion of the combined oxides of nickel and cobalt to the bulk of the stuff in the lode is 2-2 per cent, but when washed this percentage is brought up in the marketable mineral to from 13 to 18 per cent

The principal vein is about one foot wide. It is filled chiefly with quartz, garnet, and hornblende. The principal ore is smaltine, an ore of cobalt, and this is accompanied by copper nickel, blende, galena, and copper pyrites.

' Engineering and MifMiji jffmmal of New YorkyoX, xxv. p. 187.

288 METALLIFEROUS MINERALS AND MININa

In South America nickel is found in Brazil along with other ores.

New Caledonia. — Large deposits of nickel have recently been discovered at Mount d'Or, twelve miles from Noumea the capital of New Caledonia. The mountain rises about 1,700 feet above the sea, and is said to be a mass of nickel ore. On examination it will probably be found to consist of slaty strata, impregnated or sprinkled with the ore, and to be traversed by ramifications of veins in which the ore is concentrated. Three samples of the ore gave respectively, on analysis, 6*19, 3*26, and 7*39 of pure nickel. The first shipments of the ore to London, in the year 1875, realised 75/. per ton. About 3,000 tons have been shipped since 1874.

Associated with other ores as it is, the geological horizon of nickel seems to be that of copper, and the lower portions of the strata containing silver lead ores.

Pla Tinum.

Native platinum is a dark grey metal with a shining metallic lustre. It is distinguished both by its extreme infusibility and malleability. It is very heavy, its specific gravity ranging from 16 to 19, and its hardness from 4 to 4*5. It occurs in small grains, and occasionally in lumps weighing several pounds. The largest specimen known weighs 21 lbs. ; it was found in the Urals, and is in the Demidoff Cabinet

Thus far the metal has been obtained from superficial sand and detritus ; but it seems to have been derived originally from the same source as gold, being associated with that metal. It is always found alloyed with other metals, chiefly with the group of rare metals to which it belongs — iriditun, rhodium, osmium, and palladium. The composition of a specimen from Russia showed — platinum 78*9, iridium 5*0, osmiiun and iridium 1*9, rhodium 0*9, palladium 0*3, copper 07, and iron ii'o. It was first noticed in the alluvial deposits of Choco and Barbacoa, in South America, and attention was first directed to it by Ulloa, a Spanish traveller in America, in 1736, when it was brought to this country. On account, how-

Platinum. Iridium. 289

ever, of its extreme infusibility — the quality that now makes it so valuable — it remained for some time nearly useless. It was Wollaston who discovered the process of precipitating the platinum in a solution effected by nitro-chloro-hydric acid by means of chloride of ammonium. From this precipitate the platinum can be reduced to the metallic state by simple ignition. In this state it is a very fine black powder, which is strongly heated, compressed in steel moulds, and then hammered into shape.

In the far East platinum has been found in the alluvial deposits of Borneo, but the greater part of the platinum of commerce is derived from the Ural Mountains, particularly from the localities of Nischne Tagilsk and Goroblagodat. IE is found, like gold, in alluvial beds. These have been traced up Mount La Martiane. This hill consists of crystalline rocks, and is supposed to be the source of the detritus with its contained platinum. The proportion of the metal obtained from 3,700 lbs. of sand is given at from one to three pounds.

The metal has also been found in North Carolina, along with gold ; also in Columbia, St Domingo, and Brazil. It is also obtained in grains from veins in the Keuper sandstones of Harmer Hill, in Shropshire, into which it was possibly drifted from the older oystalline rocks of North Wales, when these sandstones were formed.

The production of Russia is from four to five tons a year, the rest of the world yielding probably another ton, of which a quarter is derived from Borneo.

Iridium,

Iridium is one of the rarer metals. It is tin-white in colour. It is usually associated widi osmium, palladium, and platinum, and also, in California, with gold. It is exceedingly hard and heavy. It has been used for a long time, on account of its hardness, to tip gold pens. Latterly, it has been employed experimentally to point the drills used in rock-boring machines, its having been found of late more plentifully in the gold mines of Western America, permitting it to be used for this purpose.

u

290 Metalliferous Minerals And Mining.

Palladium,

This is another member of the group of rarer metals, to which those just described belong. It was first discovered by Wollaston in 1803. It is of a light steel grey colour. Its specific gravity is 11 'o. Its properties are like those of platinum, but it is hardly so valuable, and it is soluble in nitric add. In Brazil this metal is found in pure grains, associated with native platinum, as well as intimately combined with the latter substance.

Tellurium.

Tellurium is one of the rarer metals. It is found native, mixed with a little gold and iron, at Facebay, in Transylvania.

It is also found in the mines of the same country combined with ochreous matter, in small white or yellowish masses, as telluric ochre. As tiagyfite or black or foliated tellurium it is found both at Nagyag and Offenbanya, in the same country. In this form its composition is : lead 51 to 63, gold 6 to 9, copper and silver i to 13, tellurium 13 to 32, sulphur 3 to 12, and antimony o to 4*5. As graphic tellurium or silvanite, it is found in the same district, its composition being tellurium 59*6, antimony 05 to 8*5, gold 26*5, and silver 13-9, with lead o'2 to 19*5.

Tellurium has lately been found in a new and interesting combination, in the Keystone and Mountain Lion mines of Colorado, Western North America. An analysis by Dr. Genth, who has paid much attention to this class of minerals, gave the following results :

Gold 0*60

Silyer 0*07

Tellurium. , 96-91

Vanadium 0*49

Oxide of iron 078

Mercuxy, oxide of aluminium, and potassium 1*15

100 'Cx>

The mineral is, however, in all its forms, more interesting scientifically than commercially.

Conclusion Of Description. 291

We have now reached the conclusion of the description of the metallic minerals selected for notice, and I pass on to review the principles that should guide, and the considerations that should affect, the search after metallic minerals and the exploration of mines, together with the appliances, mechanical and otherwise, by which the working of mines and the dressing of ores are facilitated.

Chapter Xxxii.

On The Discovery And Proving Of Mines.

Old Superstitions—The Strata containing Metalliferous Minerals--The Stratigraphical Zones of the different Minerals— Discovery of Mines, apparently accidental, not really so — SurJhce Indications — Shoding — Explorers — Prospecting — Contents and Character of Lode — Proving by Trenches, Small Shafts, Adits, Shafts, and Levels along Lode, Sumps.

A CURIOUS chapter might be written on the superstitious and magical means by which, in times past, it has been supposed that minerals might be discovered ; including that belief in the magical power of the divining rod' which even now lingers in the minds of men whom we would suppose should know better.

Our work is more practical, and I at once proceed to notice some considerations which may at least serve to keep us from searching for metallic ores where they are not to be found ; and also prevent our spending money in the prosecution of mining operations in the midst of conditions under which we cannot, ordinarily, hope for success.

This will lead me to recapitulate some of the inferences which I have already drawn at the conclusion of my account of each of the metallic ores already described.

And, first, we have seen that these minerals, with few exceptions, are confined to the older strata of the earth — from the New Red Sandstone downwards. The exceptions are, the ores of iron ; the occurrence of ores where newer strata have been pierced by, or rest immediately upon, rocks of an intrusive nature, as in the deposits of the Banat in Austro-Hungar}' ;

Recapitulation Of Inferences. 293

and where metallic ores have been drifted or otherwise derived from older strata, as in the cupreous deposits of the Triassic rocks, or of the Cretaceous strata, as in Algiers.

These are not important exceptions. Without saying, therefore, that it is an impossibility to find productive deposits of metallic ores in the Liassic, Oolitic, Cretaceous, and Tertiary strata, we may content ourselves with the reflection that, as far as the experience of the past is concerned, the occurrence of the metallic ores in these strata in paying quantities has been the exception and not the rule, and that all the probabilities are against the attainment of success in such a search. The search may consequently be left to ardent explorers who have time, money, and curiosity sufficient for the task.

It is rarely that deposits of copper in the New Red Sandstone have paid for continuous working, so that, with the exception of the ores of iron, or where the newer strata are pierced or interbedded with igneous and metamorphic rocks, it is in the strata that lie from the summit of the Millstone Grit downwards that any hopeful search for metallic minerals must be made.

There is no mistaking the locality of these older rocks. They form the elevated and rugged portions of the globe, and they have, as I have shown, all over the world a general course or direction ranging north-east to south-west

The search for all metallic ores except those of iron is thus practically restricted geographically to hilly regions, and stratigraphically to the rocks lying below the Coal-measures.

Further, the data we have collected from mines and mineral deposits spread over different parts of the world show that certain minerals prevail most in certain well-defined stratigraphical zones or groups of strata. Thus, leaving out of consideration the rarer metals, we find that tin occupies the lowest of these zones — its chief place being in granitic rocks, which are seen to underlie and protrude through Lower Cambrian strata; the known position of these tin-bearing granites in various other countries helping us, combined with

294 Metalliferous Minerals And Mining.

other considerations, to determine the age of the tin-bearing granites of Cornwall

Nor do productive veins of tin ore appear to have been worked profitably, as a rule, in the overlying schists, into the crevices, and it may be into the composition, of which grains of ore were washed from the exposed sm&ces of the older granites, while the schists were in various stages of deposition and shrinkage. We may conclude, I think, that the true home of tin is in these ancient granitic rocks.

The next zone in ascending order must be given to copper, which appears to occur in bulk in the altered Lower Cambrian strata of Anglesea, and in corresponding strata in Cornwall, America, and elsewhere.

Gold in productive quantities lies a little higher up ; its place being near the junction of the Lower with the Upper Cambrian strata, and principally, perhaps, in the lowest beds of the latter. This is its position in the gold-bearing rocks of Merionethshire, North Wales ; and we have seen how it is so widely disseminated throughout the Potsdam sandstone of Western North America, with its associated slates and meta* morphic rocks.

Silver is associated to some extent with copper and gold in their true horizons. Indeed, silver is for the most part an associated metal. Lead and blende also make their appearance early. Thus the whole of the foregoing metals, except tin, are found intimately mixed in the bluestone deposit of Morfa-Ddu, Anglesea, but the true horizons of silver-lead and blende lie higher up in the series of strata.

The lower productive zone of lead is reached in the Llandeilo and Arenig strata. It extends upwards to the base of the Bala group, and downwards to the Tremadoc Slates and Lingula Flags. It is not worked to profit in these older rocks either above or 'below these limits. This, too, is the home of silver, and from this horizon it is most abundantly obtained, cither mixed with lead or in its own rich ores, as in Western America.

Some locally productive lead lodes appear, as we have

Horizons Of The Various Ores. 29$

seen, in the Middle Devonian strata, but the next great plombiferous belt lies near the base of the Carboniferous Limestone as in North Wales. This belt is divided by a great thickness of unproductive ground from the uppermost zone that lies in the cherty and calcareous strata of the Yoredale rocks or basement beds of the Millstone Grit, as in Flintshire, Denbighshire, and the North of England

Zinc, as an associated mineral, is found with copper, silver, and gold in the bluestone deposit of Anglesea, and in similar old rocks elsewhere up to the summit of the Carboniferous Limestone. Its great productive zone lies, however, as in Belgium and North Wales, in the middle beds of the Carboniferous Limestone ; its next productive zone being lower down in the lead deposits of the liandeilo and Arenig strata. To these two well-defined zones we must add the unique deposit in Silesia in the limestone beds of the Muschelkalk, as described on page 243.

Here, then, we have the accumulated results of all past experience guiding us to well-defined stratigraphical horizons, where lie the chief deposits of the different metallic ores. These horizons glide into and are connected with each other vertically, 'but it is evident, I think, that the chances of successful search for any particular mineral lessens as we search up or down away from the belt of strata in which it has been proved to attain its richest condition.

For example, tin disappears upwards as we ascend from its granitic home. Copper gives place to tin in depth, and it has seldom been worked long successfully above its Cambrian horizon. When lead lodes pass downwards into the underlying Lingula Flags they cease to be worked with profit Upwards, as they enter the Bala Beds, they become charged with sulphate of baryta with occasional spots of lead, and this alteration continues up into the overlying Wenlock Shales of the Silurian group of strata, for mines worked in the old-looking shales of North Wales, as near Llangollen and near the Vale of Clwyd, yield much baryta but little lead.

Given, now, a district where, stradgraphically, the conditions

296 Metalliferous Minerals And Mining.

are favourable for the presence of any one of the metallic ores, how may its existence be ascertained, and the places where it lies be discovered ?

As a matter of experience we have seen that many of the richest mines have been discovered by accident The wayfarer resting in the wilds of the Saxon forest, and picking up carelessly a stone ; the muleteer in Brazil scrambling after his mule, and pulling up a tuft of grass with grains of gold about its roots ; the digging of a mill race leading to the race for gold in California ; the laggard pilgrims attracted by the silver ores of Ruby Mountain ; the curiosity excited by the great weight of the stones in California Gulch leading to the discovery of carbonate of lead. These are a few examples of what at first seems to be the accidental discovery of mines. In similar ways, by the shining grains of gold in the rivers along which they fished, were the Indians led to the discovery of gold in South America ; the heavy deposits of stream tin in the rivers of Compl would attract the attention of the Cornish Celts, and the bog impregnated with copper the old Britons of North Wales.

But such discoveries were accidental only by reason of the previous ignorance or indifference of the dwellers in the land, or from the absence of inhabitants if there were none. For in each of the above illustrations there were natural indications which would make it plain to intelligent seekers that valuable minerals were near. Grains of gold in a river-bed, lumps of lead lying in the flats and hollows of a hilly coimtry, springs of water charged with copper or iron, point as clearly as they can to deposits of like metals of more or less value lying near. On the whole, man has in the past been more slow to learn than nature has been to teach him the way to her hidden treasures.

It is the intelligent and persistent following of such indications that has often led to the discovery of' the parent deposits.

Thus, in Brazil the miners have followed the alluvial deposits of gold to the auriferous half-formed rock cemented together with

Shoding. Trenching. Explorers. 297

iron, and beyond this to the real rock with its imbedded gold. The Australian has followed his recent river deposits to the more ancient deposits of the same character, and at last to the quartz reefs themselves. So with the Califomian. The cupreous stream ia Anglesea revealed the spot where the great copper deposit could be struck. Of later years, and only recently comparatively speaking, the Cornish man has folded his stream tin up the streams to its parent granitic rocL

The name given in Cornwall to this following of grains and fragments to Uie source whence they were originally derived is ' shoding,' because the mineral was traced to the point or ridge where it had been shot or shed off from the original deposit It is soon known when this source is passed upwards, by the cessation of the appearance of the minerals sought for in the drift and soil

When such a point is reached, should the rock be covered with driftal matter, trenches have to be cut down to the rock, so as to expose a lode, if there is one, and experience soon teaches the explorers that it is better to cut across, rather than along, the known course or direction taken by the strata of a district

In mountainous districts the strata are already laid bare, and cut through to a great extent, by the streams that run down the hill sides. In such districts, too, there is always at least one man to be found who is a bom explorer. In Wdes he is often a shoemaker who cannot stick to his last; more seldom a blacksmith, and more rarely still, a gamekeeper or a shepherd. Such men are generally possessed of intelligence above the amount required for their ordinary calling in life. They are often men who love nature for her own sake. They love the freedom of outdoor life also, and they spend much time in lonely rambles in mountain regions, exploring the bed of every beck and bum. It does not detract from them to admit that they are often prompted also by the desire of acquiring money and fame, which they could not hope to get at their* own trades. I know several such men. The world owes to them more than it will ever pay. Few things, too, are more enjoyable than a

298 Metalliferous Minerals And Mining.

walk or mountain scramble with such a man to the object of his discovery and enthusiasm and many such walks and scrambles I have had.

These men are the pioneers of mining enterprise. They search along the beds of all the streams within their reach, noting every white vein of quartz or spar of any kind in the rock ; sing out specks of pyrites which may lead to lead or copper, as the case may be, and carefully observing every local change in the structure or composition of the rocks themes. In this way, therefore, by diligent search along mountain streams, lodes and other deposits of metallic ores are intelligently discovered.

In the Western States of America there are now organised bands of such explorers, who make systematic searches during the favourable portions of the year. They are usually experienced miners, and they have a keen eye for anything like a metallic ore. They soon learn also that, as the most persistently productive metalliferous lodes run, roughly, east and west, it is in the river beds and gorges that cross this direction in which they will have the most chances of success.

It will be readily understood from the remarks made in the firsi; half of this chapter that a little geological knowledge, and an acquaintance with the most metalliferous zones of strata, would have saved all such explorers much vain search. For example, there would in our own country have been Uttle need to have searched for lead in the widely spread regions covered with the deposits, many thousands of feet in thickness, that lie between the summit of the Uandeilo Beds and the middle of the Devonian series.

A metalliferous lode having been found in a suitable position, it must next be observed that it seldom shows its contents in their true condition near to the surface. There it is more or less in a decomposed condition. The iron which, in the form of pyrites, is present in most metallic lodes has become an oxide by long exposure to the atmosphere, and it presents the rusty appearance known as gossan. Of course there may be nothhig in the lode below but iron pyrites, but usually there

Indications Of Various Lodes. 299

are associated metals of more value. Hence the German

rhyme —

There is no lode like that, Which has an iron haL

The kind of metallic mineral lying below, if any, may be inferred in two wa3rs : first, from the particular horizon of strata, that is, the geological formation, and the particular part of that formation in which the lode lies ; and, secondly, from the colour of the associated matter— copper being oxidised or carbonised, giving a reddish or greenish hue, tin a blackish, lead a greyish, and blende a yellowish brown colouring to the deposit Following the lode down beyond the action of the atmosphere, the presence of each metal will become better defined, and will assume its true characteristics and proper appearance.

The question of the probability of the productiveness of a lode will be afifected at the outset by some general considerations, as the following examples will show. If it is a tin lode, by the character of the granite in which it occurs — is the granite schorlaceous and partly decomposed, the condition under which, as we have seen, tin is most plentifiil and is most profitably worked ?

If it is a supposed auriferous quartz reef, has the quartz that massive, compact, opaque form in which, as a matter of experience, gold is least plentiful? or is it comby, drusy, sugary, and plentifully sprinkled with pyrites, which have proved the conditions in which gold has been most abundantly found ?

If it is a true silver lode in the older rocks, does it lie in metamorphic rocks either as a true vein running across them, or as a parallel and contact sort of vein, like that of the Cornstock, shown in fig. 39 ?

If copper, is it in ordinary clay slate, where usually copper is not found in payable quantities? or in metamorphic, homblendic, and chloritic slates, like those of Cornwall and Anglesea? and are these associated with igneous rocks, hke those of Africa and of the mines of Lake Superior ?

If it is a lead lode in the older strata, is the lode a hard, compact, quartz lode, with only spots and strings of lead, which

300 Metalliferous Minerals And Mining.

is unfavourable? or a loose, sparry lode, consisting of quartz, carbonate of lime, and other sparry matter, with lead filling the interstices, which is favourable ? Is it an ill-defined lode, filled with fragments hardly distinguishable from the surrounding rock, and containing very lite spar, which is un&vourable ? or well defined, with these fragments cemented together by plenty of quartzy and calcareous spar, and with lead sprinkled throughout, which is more &vourable ? If composed chiefly of blende near the surface, does the blende give place to lead in depth, so as to verify the saying which is more applicable to lead lodes in these old rocks than to those in the Carboniferous Lunestone — ' Black Jack rides a good horse ? '

These, among other considerations, which will be suggested by a perusal of the foregoing pages, will help very materially to determine at the veiy beginning, or nearly so, whether a lode or other deposit is worth much further exploration.

Supposing the general conditions and appearances of a lode to be favourable, the question next arises, ' What are the best ways of proving its capabilities? ' in order to decide the further question, ' Is it worth while to incur the cost of buildings, machinery, and plant ? '

If a lode crosses a comparatively fiat district, where it cannot be struck in depth by means of an adit level, it will be proper to proceed to prove its capabilities in one of the following ways : First, by sinking, with the help of a windlass or horse whim, small shafts along its course. This process is known in Cornwall as ' costeaning.' Secondly, by taking a shaft down the dip or hading of the lode to a depth of lo or 20 fathoms, and at a likely-looking place to carry a tunnel right and left for some distance along die course of the lode, and, if the exploring shaft is taken deeper, by driving a similar level 10 or 15 fathoms below the first In sinking such a shaft it should be observed in which direction the shoots or courses of ore dip. The direction taken by them will influence the driving of the levels, as well as the distance apart at which these levels should be driven. Or, thirdly, if the prospects of the lode are at first pretty good, a perpendicular shaft may be taken down

Preliminary Proving Of Lodes. 30I

SO as to cut the lode at a given depth, like the shaft at the Van Mine, only it need not be so deep, as shown in fig. 83. From the point at which it strikes the lode, levels may be taJcen right and left along the lode in order to prove it, as in the second case. If the prospects are very good, this shaft may be taken down of sufficient size and depth for permanent use, and adapted for pumps and cages as in a coal mine, or as shown in fig. 119. Ordinarily, however, at the commencement of a mining undertaking, it will be more prudent to take it down of a smaller size, but suitable for an air shaft when the mine is worked.

As the sinking of shafts entail the cost of winding and pumping, wherever possible a lode should be proved by means of an adit level, driven so as to cut the lode at as great a depth from the surface as practicable.

Where, as in the Cliff Mine, fig. 61, a lode runs down the face of a hill into a valley, the adit level should be taken along the lode, proving it every fathom it is driven. It is desirable also that sumps, winzes, or small shafts should be sunk at intervals along the floor of the level down the course of the lode to prove it in depth.

Where, however, a lode runs parallel to the face of a mountain, the adit level must be driven as a cross cut to intersect the lode, as in the case of the Van lode, fig. 83, or as in the case of the deep level now being driven with a view of cutting the copper deposit of Anglesea in depth, as shown in fig. 53. When the lode is reached, levels will be driven along it as in the former case.

We have already seen that lodes are more productive, even in mineralised zones of strata, in some beds than in othersL Care must therefore be taken not to drive along the lode in soft strata, where the lode is comparatively unproductive, as is too often done ; nor in those bands of hard rock where the lode is pinched and often poor ; but in the beds which are known as usually the most productive in the district.

It will be seen, therefore, that one of the essential qualifications of a mining engineer or mine captain is a tolerably exact

302 Metalliferous Minerals And Mining.

knowledge of the geological structure of the district in which he works, together with the character, composition, thickness, and the amount of the inclination of the strata traversed by a lode. Otherwise he may be found spending money in vain by driving in the soft or gritty beds that lie between runs of ore like those shown in the diagram of the Snailbeach Mine, fig. 8 1, or in the unproductive shale beds of the Carboniferous Limestone, shown in figs. 90 and 95.

Chapter Xxxiil

On The Working Of Metalliferous Mines.

Shafts : Vertical, Diagonal — Arrangement — Winding Compartment — Pumping Compartment — Ladders— Man-Engines — Cages and Guides — Adit Levels — Working Levels — Winzes — Stopes — Timbering — Ironstone Mining in Coal-measures — In Jurassic Strata.

I WOULD explain at this that it forms no part of the design of this book to enumerate the details of mine carpentry or mechanics, or to give a minute description of mining tools or the way to handle them. I propose to give general principles, with selected illustrations of their application, and I would refer the unprofessional reader who may desire to pursue this part of the subject in greater detail to the excellent lectures and books mentioned below. '

The young professional reader will, in addition to the careful study of such books, learn such details best in actual practice at a mine.

As far as actual excavation goes, metalliferous mines are worked by means of shafts levels winzes and stopes. I have already in the last chapter referred to the two first of these — shafts and levels —but it will be necessary to notice them more particularly in their relation to the .permanent working of the mine.

W. W. Smyth's Lectures on Mining,' Mitting ytmmal, 1875- ; Jefferson, Notes on Clausthall Lectures on Mining,' Mining JoMmal, 1877-8-9 ; J. H. Collins, A First Book of Mining and Quarrying (Crosby LockwoOd & Co.) ; William Morgans' Manual of Mining Took, with Atlas of Engravings (Crosby Lockwood & Co.) ; G. G. Andre, Mining Machinery Tools, df*c. (E. & F. N. Spon).

304 METALLIFEROUS ItflNERALS AND MINING.

As far as practicable the preliminary exploratory work should be planned so as to fit in with the general subsequent woiking of the mine, if the result should prove successful,

IV VlRTICAt ShATT.

and the following considerations would have to be taken into account in fixing the site and position of the works :

Charatier of shafts.— Oat of the first questions to be

Perpendicular And Diagonal Shafts. 30$

decided will be the character of the proposed principal shaft of the mine. Is it to be pcipendicukri or sloping down the dip of the lode?

If the dip or ' hading ' of the tode is steep ; if the known productive ore strata are of great thickness, as in the Van -Mine, &g. 83, or if not thick the dip is very great, and the lode dips in the sau.e direction, as shown in hg. 116, the shaft should be vertical

unUL 313, Lode 4, Fill. s- Codudiu-

The 'hading ' of the lode and the dip of the strata being known, the shaft should be placed so as to command as large a portion of the lode as possible with the smallest amount of cross-cutting. If, for example, it is known that, bairing unknown fiiults, the mine may be worked to a depth, say of a hundred &thoms below adit, the shaft should be arranged so

306 Metalliferous Minerals And Mining.

as to intersect the lode 50 fathoms or half-way below the adit, leaving the latter to provide for the working of the portion of the lode that lies above it If the lode be a flat or gently sloping lode, or if the ore-bearing strata are thin, or dip in a contrary direction to the lode, it will be better to work the mine by a sloping shaft driven down the course of the lode, as shown in fig. 117, to the base of the strata, or continued to productive strata below, where probably there may be floors and coiuses of ore.

In slanting shafts the angle of the incline will be a£fected at times by faults or by variations in the course of the lode as it passes through soft yielding strata. In such cases the good miner, having found tiie lode, will be careful to take the shaft down to it as nearly on one plane of inclination as possible, as illustrated in the figure 117.

These two examples of shafts will afford a clue to determine the course to be pursued in other variations of condition that may occur.

The chief points to be determined are : the amount and the direction of the dip of the strata ; the amount of ' hading ' and the direction of the lode; and the character of the strata in relation to the productiveness or otherwise of the lode.

A good example of a slanting shaft is seen at the Botallack Mine, Cornwall, and another, on a much smaller scale, at the Llanrwst lead mine, Carnarvonshire. Many examples occur in the Erzgebirge mining district of Germany.

The position of both kinds of shafts should also be fixed, if possible, so as to have a fall for the ore from the pit's mouth through the dressing sheds to the ore bin.

Size and arrangement of shafts, — These principal shafts of a mine should be of ample size, for (i) the winding up of the ore ) (2) for pumping ; and (3) for the ingress and egress of the miners. Fig. 118 is a representation of an ordinary vertical shaft. I is the central winding compartment ; 2, the pumping division ; 3, the ladder way; 4, the platform at the junction of the ladders; 5 is an intermediate level or cross-cut; and 6

Internal Arrangement Of Shafts. 307

shows a pordon of the partition by which the ladder way must now be shut off from the rest of the shaft.

Usually, and especially in small mines, the arraiigemeni is less complete, the shafts in limestone mining; districts, for example, often being not more than 4 feet in diameter, with scarcely room for kibbles of the size of large buckets to pass each other. 1 2 feet by 9 feet may be given as the ordinary size of a shaft, such as is shown in fig. 1 1 8. 14 feet by 10 feet would be better wherever it is practicable.

The common winding arrangement is that shown in the figure. The Icibbles being unguided, the winding has to be carefiil, and comparatively slow, lest the Itibbles should come into collision in passing each other, which they sometimes do, a swinging and rotatory motion being almost unavoidable. In this respect metalliferous mines are behind collieries, in most of which now guides of wood or iron are fixed down the shaft for the guidance of cages, which have

been substituted for loose p,o. ,ib._ii,tiinai. swinging bowks or kibbles. "' SH*n.

In some of our principal mines, the Van, for example, this better arrangement has been adopted, with great saving of manual labour and money in the extraction of the ore. It can, of course, be adopted in the case of sloping or diagonal hafts ; and after a mine lias attained a certain depth, or arrived

308 Metalliferous Minerals And Mining.

at a certain stage of development, the adoption of guides and cages should be rendered compulsory.

The chief difficulty in sinking shafts consists in passing through the superficial drift or bog that overlies the solid rock. Ordinarily this is not so thick or troublesome in metalliferous mining districts as in colliery districts. Still a good thickness of loose or boggy matter is sometimes found. The great thing

in such cases is to get a set of good sinkers who know their work, and to furnish them with a plentiful supply of planks and poles. By driving these close together as a piling, and in a sloping direction, away from the centre of the shaft, as shown in fig. 119, the worst ground will be gradually got through. Of course, the looser the ground the more closely and carefully should the planks be fitted and protected from an outward as well as an inward thrust

The shafts I have described are

":"b gU'd'""'"''' used largely for the passage of the

I X, Plank piles, a 2, Square miucrs to and from the workings of

"° the mine, and the mode of this passage

has been chiefly by means of ladders, as shown in fig. ii8.

Formerly these ladders were of great length, and were fixed very steeply, often perpendicular, and overhanging at the top, so that nearly the whole weight of the ascending or descending miner hung upon his hands and arms, by which he had to pull himself up, or let himself down.

By the Metalliferous Mines Regulation Act of 1872, the ladders must now be fixed, as shown in fig. 118, at 'the most convenient angle which the space in which the ladder is fixed allows, and every such ladder shall have substantial platforms {4, fig. 118) at intervals of not more than 20 yards.' The separation of this part of the shaft from the other divisions is adso now rendered compulsory.

Man-Engines.

Still the ascent of men from mines ranging from 100 to aoo fathoms in depth is veiy laborious and exhausting, especially coming as it does at the close of a hard day's work. It takes the strength out of the men, and it has been proved to induce various diseases, and to materially shorten the miner's life.

During the last hundred years mines have attained a depth previously unknown, and attention has been directed towards the discovery of some way or other by which this laborious process may be avoided.

It occurred to a German miner in the Hartz, as he looked at the action of the pump rods,' whether it would not be possible 1 by placing steps on simUar rods opposite to each other to raise a man up the length of the ascendmg rod, and then by his stepping on a platform on rod which had just descended he could be ; raised by the length of another stroke, and so on to the top of I the mine ; time being given between the strokes for the man to step from one platfonn to another. :

This idea resulted in 1 ' Man-Engine,' Fahrekunst, the Germans call it, which was J adopted in the Hartz mines in I the year 1830, and some time ' afterward in the Tresavean Mine j in Cornwall.

In the latter county the ma- I chines are now formed of solid wooden rods, like pump rods. P'g. ho.— sbctiob 01- shah, with The stroke of the rods is la feet, 'man-Emck-

and 5 strokes a minute gives 60 feet in that time, or loo&thoms every ten minutes. The machines, of which fig. 120 will give an idea, are worked by engines placed at some distance from

310 Metalliferous Minerals And Mining.

the shaft, and with which they are connected by means of horizontal rods like pump rods — care being taken to avoid sudden and jerky action.

A very important man-engine is now in course of erection at the Maria Shaft at Przibram, in Bohemia, to replace one made of iron that has been in use since the year 1867. The total depth of the shaft will be over 1,000 yards. The rods for the machine are made of the best steel, so as to combine lightness with strength. The rods are made nearly square in shape, being a little longer in one direction than another. The lowest rods are slightly under i inch square, and the size is increased upwards, until at the top they are nearly inches square. The rods are coupled by having square projecting heads, over which are placed claw-ended coupling plates. In the lower part of the shaft the motion of the rods is protected by guides. The platforms are made of sheet iron about the seventh of an inch thick. They will hold two men, and they are placed eight yards apart The total weight of the machine — both rods, platforms, and all appliances complete — is 77 tons ; with 260 men on it the weight is about 18 tons more. The machine is worked by a steam engine with a 22-inch cylinder and a 3-foot 8-inch-stroke.

Jn some mines the ascent and descent of the miners are now made by cages, working between guides, as in well-appointed collieries. Objections were long entertained against the adoption of this method on the ground of the supposed difficulty of landing the men at the various levels in the mine where their work lay, but as this difficulty has been overcome in collieries, it no longer exists.

The same may be said with reference to another objection, that of the long time that would be required for taking from 200 to 300 men down a mine a few at a time. Those who have seen the same number of men go down a coal mine between five and six o'clock of a morning well know how rapidly two cages, each perfonning its journey in two minutes, and each cage holding six men, will take 300 men into the mine.

The time has now come, I think, when the adoption of

Adit Levels. 311

man-engines, cages, or any other means whereby ladder climbing can be avoided, should be made obligatory at all mines over 50 &thoms deep.

It need hardly be said that the timber and timbering used in shafts should be of the best quality and workmanship. The platforms, as long as they are used, should be firm and good, and the pump trees adequately secured according to their size and weight The whole of the pit arrangements should be firequendy examined.

The price paid for sinking shafts varies greatly according to the nature of the ground and the inflow of water. In ordinary ground a shaft 14 feet by 10 feet should be sunk and

secured for 15/, per yard— carpentry, gearing, and pumps being, of course, extra.

L.EfBLS.—Adit /eveis. — The adit level, as I have already pointed out, is driven at as low a point on the ground as possible. It is intended to serve the double purpose of draining the loose surface ground above it, and for working the upper portion of the mine. Seven feet high and 6 feet mde is a convenient ze, and the price paid for driving it will range from 4/. lor. per fathom, in shale and slaty rock, to 18/. or 20/. in compact felspathic roclc or rolled greenstone. There should be just fall enough outwards for the water to run oS, and the level should have spaces at intervals for the passing of the tram waggons.

As in the case of a shaft, the chief difficulty in driving a level is in the loose ground at its entrance. This should be cut

312 Metalliferous Minerals And Mining.

down as far as practicable, and the level approached by a good open cutting with sloping sides. If further difficulty is found, the roof may be secured by piles driven in, as shown in fig. iji, which should be placed high enough for the permanent roadway to be formed underneath them. When made, the entrance should be well secured, which may be done with poles, as shown in fig. laa, or by masonry, as in fig. 133.

Ordinary working levels. — One of the first things to be determined concerning ordinary levels is the distance at which they should be driven ftm each other. Usually in mines in

this country that distance has hitlierto been 10 fathoms. Latterly, in some important mines, the Van for instance, fig. 83, the distance has been increased to 15 fathoms. The Americans in their larger mines have adopted 20 fathoms as the distance.

If the ore lies in fiat strings or floors, the lesser distance is more likely not to miss any of them. If the courses run down steeply, as at Snailbeach, fig. 81, there is not the same necessity for driving the levels so dose

The distance apart to be adopted must therefore depend upon the character of the mine ; but, wherever practicable, the

Ordinary Working Levels. 313

greater distance should be adopted. It must be remembered that the ore in each square of the lode, bounded on either side by shafts or winzes, and above and below by levels, has to bear the cost of driving one level and one winze, consequently the smaller the square the greater the proportion of cost per ton chargeable on the ore for forming these. '

To take an example. A square, 10 &thoms by 10 fathoms, of a lode, yielding an average of 2 tons of ore to the fathom, contains within it 200 tons of ore. Taking the cost of driving the level with all expenses at 7/. los, per fathom, and the cost of the winze at the same price, the total cost is 150/., which makes a charge of 15. per ton on the ore contained within the square. If the area is enlarged to 15 fathoms square, the cost per ton will be i is. d, ; if to 20 fathoms, the cost will be reduced to 7x. 6d, ; and as cross-cuts have to be made, these figures do not represent the whole of the saving effected. Thus it is clear that tiie farther apart the levels can be kept, compatibly with the effectual working of the mine, the cheaper will be the cost of the extraction of the ore.

The ordinary cross-cuts a shaft to the lode, and the levels along a lode, need not be of such large dimensions as those given for the adit, but little is gained by contracting the size of these.

In the cross-cuts the strata will usually be solid enough to form the roof; but the driving of the ordinary levels along a lode is only the preliminary operation to the cutting of the lode above the level down. When this is done, the top of the level will have to be made strong enough to bear the deads,' or rubbish thrown down from the working of the lode above, or, if all the lode is taken down, to secure the roadway from stones falling firom the working face. This has to be done by timbering, in the following ways, or variations of the same, as special circumstances may indicate : if the workings are narrow, as in fig. 124; or, if they are too wide for a single stretcher, the full length, as in fig. 125.

The timbers should be from 7 to 9 inches in diameter, and placed a yard apart, with a good covering of thinner poles.

314 Metalliferous Minerals And Mining.

Sometimes the roof timber is taken right across a lode to a great width, being supported on the heading side of the level by Strang uprights. In the Botallack Mine, where the lode is 23 feel wide, massive timbers of from i6 to so inches square form the roof, and these are often placed double, the beading side of the level being filled, as in &g. 125, with nibbish.

Winies. — These are small shafts sunk at intervals from one level to another, partly for ventilation, hence the derivation of the name 'winds,' and partly for greater facili in working

Rixdwiy. a, Raarciraben. i, Rulibuh. 4. Working ipue. s. Lod C, Smu ji put of irhidi by the ulc of the lode hu u be taken oowd. ena fornu rabbuta

the slopes. These may be placed the same distance apart as the levels, or a greater or less distance, as the mine may require.

The preliminary sinkings on a lode in order to prove it, referred to in the last chapter, should be arranged so as to form winzes as far as they go.

Slopes. — The working faces on a lode are called 'slopes' or steps. They are of two kinds, underhand and overhand. Underhand slopes may be compared to a man working on a flight of stone steps, and cutting away step by step, and overhand Slopes to the way in which a man may stand, say on the

Stopes And Stoping. 315

cellar steps, and cut down the flight of steps over his head. Up to the last century, underhand stoping alone was practised in this country, when the overhand system was introduced torn GeriDany, where it had been in use for some time. Fig. 196 will afford an idea of overhand stoping.

When the ore has been extracted out of a laige space of a lode, the walls or sides of the latter have to be supported. If enough of rubbish is not left from the working of the lode to do this, it must be accomplished by timbering, and this' has often to be of a very substantial and elaborate nature, like a huge lattice or panel work. If the lode be very wide, like that of the Van, or the Great Comstock, or the vast ore chambers of Ruby Hill, scarcely any amount of timbering will the

strain and pressure caused by the caving in of the surrounding ' rocks. The plan is therefore adopted of taking rubbish from the surface, where it may be easily and cheaply excavated, into the mine, and filling up with it the spaces &om which the ore has been extracted

In ironstone mining, in the seams lying in the Coal-measures,

3l6 METALLIFEROUS MINERALS AND MrNlNO.

about three tons of material have to be removed for one ton ol ironstone. The workups are usually gently sloping, and the rubbish is thrown back to form a goaf, or gob, as shown in fig. 127, which represents long wall workings in the clayband ironstone of Warwickshire.

t. Air uoffiagi. Cootinooui liiKt, Ful idi in cotL DodEd Unci. Ihhukhm wntcoune of ihc >ir. portion Worked ponionofiRKinoneiKfoiC

Fig. ia8 represents a common method of working the Cievehind ironstone bed by the pillar and stall system. After roads have been formed and ventilation secured, a solid square of the bed is attached, as shown at 4. The process goes on until ventilation is obtained in the stall by opening

Ironstone Mining. 31/

throih and taking away part of the pillars, as in 5 ; until all excepting the side supports are left, as in 6. As a part of the mine becomes exhausted, the pillars are removed and die ground allowed to iall in behind the miners. But a good deal

of timber is necessarily used in the temporary support of the roof as the workings proceed

Chapter Xxxiv.

Oat The Working Of Metalliferous Mines—

Omtinued,

Timber — Ventilation — TemperatuFe — Fans— Old Methods of Breaking Rocks down — Drilling — Single Hand — Double Hand — Underhand — Rock Drilling Machines — History — Classes of Drills — Principles of Construction — Detailed Construction — Air Compressors — Receivers Pipes— Hand Boring Machines— Jordan's — Victor's — Faber*s.

Timber. — It will be inferred that a large quantity of timber must be used at a metalliferous mine ; and for the most part this has to be of larger dimensions than the timber used at collieries.

In newly settled countries, like the Western States of North America, the existence of Mumber/ as the wood of the country is called in the neighbourhood of a mining camp, is of great importance. In ch countries, too, the miner is glad to take any kind of timber that comes to his hand. In older settled countries, as in the mining districts of Germany and of this country, a little power of selection may be exercised

Welsh miners like oak, and, for its strength, its durability, and its power of resisting decay in moist, confined places, it cannot be excelled, if it can be got of sufficient length and strength. Next comes larch, which, from its straightness and durability, is a very useful wood. Then follows pine, fir, and deal. Beech and birch, too, where there is plenty of ventilation ; but they soon decay in a damp, confined atmosphere. Ash is tough, but too flexible for timbering the interior of mines. Alder, ebon, maple, poplar, and willow are all more or

The Ventilation Of Mines. 319

less unsuitable. Of course timber is best if it has been felled at the proper season of the year, and if it is used dry. Various chemical preparations have been used for coating and saturating it with a view to its preservation ; but these all seem now to be merging into the plan of creosoting, which answers very well.

Ventilation. — Metalliferous mines are not troubled with such explosive and actively dangerous gases as coal mines are; happily, therefore, they are firee from those sudden outbursts of inflammable gas which unfortunately are so frequently fatally destructive to a dreadful extent at collieries.

Still, there are the facts that the air in a mine is nearly stationary; that by being breathed by a nimiber of men it loses its vital properties ; that it is poisoned to some extent by noisome exhalations ; that it becomes chaiged with the fumes of explosives ; and that there are occasionally outbursts of hydrogen gas where saline water falls on blende ore. Added to these considerations, there is also the natural increase in the temperature of the earth downwards, towards its centre.

Concerning this last remark, I may here notice incidentally, that, from observations made by Mr. Henwood in Cornwall, Professor J. Phillips in the North of England, Mr. Bryham in Lancashire, and Professor Reich in Saxony, as well as from the results obtained by other observers, the temperature of the earth increases downwards at a hite varying from i degree Fahr. for every 45 feet in depth to i degree Fahr. for every 76 feet in depth. It may be taken as the average result that the rate of the increase of heat is i degree Fahr. for every 65 feet in depth.

Ventilation is needed very early in the progress of a mine, before the first level is taken in very far, or the first shaft sunk very deep. In figs. 122 and 123 an airway is shown running under the roadway of the level, which is a good arrangement.

Many mechanical contrivances have been used in different coimtries and at different times for carrying fresh air into mines, but they seem likely now to be superseded by the simple circular fim, of which many varieties are made by mechanical

320 Metalliferous' Minerals And Mining.

engineers. I have found a fan 2 feet 6 inches in diameter, driven by a donkey engine, or by a six or eight feet water wheel, suffice for the preliminary stages of a mine. The air may be sent into confined places within a mine by means of a small fan placed where the air is pure, and turned at intervals by a boy.

Ordinarily, in shallow mines, when two shafts have been sunk, or when the air entering a mine and coursing through its workings can pass out through an upper opening, the ventilation will be sufficient If, however, many men are employed, if blasting be frequent, or if the mine be deep, the ventilation must be aided by mechanical means. Nothing can be better for this purpose than fans, which are now made of all sizes up to 40 or 50 feet in diameter, and which may be used to exhaust the foul air in a mine, so that its place may be occupied by fresh air rushing down the shafts, or by sending into the mine a volume of fresh air, which shall expel the foul, and keep the mine sweet and clear.

Where rock boring machines like those to be next described are used and worked by air, the proper ventilation of the mine will be accomplished without the use of any other means.

Boring or Drilling. — Rock Drilling Machines, — Of course, in the vast majority of instances, the lode and the enclosing strata are too hard and compact to be broken down by pick, or by the hammer and gad, or wedge. In the early days of mining, the rock was heated by lighting huge fires close up to it, and then, by throwing cold water over the heated surface, or by natural quick contraction, the rock was broken down. Quaint illustrations of this process are given in Agricola's old book on mining. This practice lingered until very lately, if it does not continue still, in some of the mines of the Hartz, in Germany.

The invention of gunpowder afforded a more effectual method of breaking down solid rock ; but for the insertion of the explosive holes had, of course, to be made. The making of these holes was and is known as boring or drilling. This operation had to be performed by manual labour, with iron bars

Rock Drilling Machines. 32 1

tipped with steel, and more recently by steel borers, or drills themselves. These are of various lengths, and are about one inch diameter. Hand drilling is called ' single-handed ' when one man holds a drill with one hand and strikes it with a hammer weighing about 4 lbs. with the other. It is double-handed ' when one man holds and turns the drill, while another man strikes it with a heavy hammer weighing about 10 or 1 2 lbs. Or, if the work lie under the miner's feet he may drill a hole by Hfting up a heavy drill and letting it fall. The usual rate of drilling by these means is one foot per hour. It is a slow, laborious process, and we do not wonder that attention was very early directed to the finding out of some means whereby, with the aid of mechanical means, manual labour might do more work, or by the application of other motive power, a better result might be attained, as a greater number of heavier blows were more quickly struck.

Rock Drilling Machines} — It is said that attempts in this direction were made in Cornwall during the last 150 years. In 181 2 Richard Trevethick, whose inventions have been the precursors of many useful appliances, invented a rotary machine for boring, which, with a weight of 500 lbs. placed over the drill, bored i-inch holes in Plymouth limestone, at the rate of one inch per minute. In 1838 two Americans, J. M. and J. N. Singer, used a large drop-drill on a portion of the Illinois Canal, about 30 miles below Chicago. The invention was patented in 1839, and about a dozen machines were put in use. In 1844 Mr. Brunton, known in this country in connection with furnaces, invented a wind-hammer for boring holes and ventilating the working face of mines. In 1853 William Pidding invented a hammer, fitted on a frame, to be worked backwards and forwards

See Darlington on Rock Boring,* Mining Journal August 4, 1877, etseq.; Darlington, ' Lecture on Rock-Boring Machinery,' ibid, December 14, 1878 ; Raymond, Statistics cf Mining West of the Rocky Mountains Washington, 1870 ; Leslie, ObserwUions on Machine Rock- Borings E. & F. N. Spon ; Schiam, The Application of Machine Power to Rock Drilting, G. H. Hill, Westminster Road, 1878 ; also the catalogues and circulars of the various makers as advertised in the Mining and Engineering papers.

Y

322 METALLIFEROUS MINERALS ANp MINING.

by steam power, for the purpose of making holes in the end of a level About the same time Schumann invented a machine, which largely anticipates the present rock drilling machines, for working the Freiberg mines, and a neat model of this machine is preserved in the museum of the School of Mines at Freibeig.

In January 1855, Mr. Fontainmoreau applied for a patent in England for an improved machine for boring rocks, by the use of compressed air in the cylinder for giving the blow to the drill The invention comprised arrangements of valves for getting the air into the compressor, and an arrangement also for giving a rotary and forward motion to the drill. In August 1855, Mr. Bartlett patented a similar invention, and his machine was tried in the driving of the Mont Cenis tunnel In 1861 M. Sommeiller, having made substantial improvements, started his machines successfully in the driving of the same tunnel. Sommeiller*s machines may have the credit of being the first that were successfully and continuously used underground, and driven by compressed air. From that time until now many improvements and alterations have been made, of which I select the following :

In 1862 Edward Crease, who had been experimenting some time previously, patented a boring machine, which was afterwards used at the Clogau Gold Mine, North Wales. Its rate of boring was inch a minute. In 1866 Jordan and Darlington devised plans for turning the boring tool, and for giving a forward movement to it. In 1870 Osterkamp made a machine portable enough to be held by a man when it was doing its work ; but the recoil was found to be too great, and a carriage or frame had to be adopted. The inventions now became very numerous, including the Beaumont, the Burleigh, McKean, and others ; but it will be readily understood how the latest improvements are new applications of the principles embodied in the first attempts.

Rock drilling machines may be grouped into two great classes. First, those that bore by constant pressure and rotation ; and, secondly, those that bore by percussion, combined with a rotary movement.

Classification Of Rock Drilling Machines. 323

The typical example of the first group is the Diamond Rock Boring Machine, constructed firom the patents of Messrs. Beaumont and Appleby. The principle of this machine is a rapidly rotating hollow shaft, on the bottom or boring of which are fixed a number of diamonds. The machine is usually worked by steam, and its speciality is that it brings up, every time the rods are changed, solid cores of the strata passed through.

The machine is, therefore, specially adapted for prospecting, for which purpose it has been largely used, as well as for working in larger tunnels. I believe the inventors have more recently adapted it for working in the more restricted spaces of mines.

The second group may be subdivided into the following lesser groups :

1. The Direct Acting system, including Cederblom's, Darlington's, Osterkamp's, Schram's, and Reynolds' machines.

2. The Duplex system, comprising the machines of Somraeiller and Ferroux.

3. The Lever system, in which are included the Barrow, Brydon, Burleigh, Cranston, Davidson's, Dunn's, Eclipse, Ingersoll, McKean, Schumann, and Warrington drills, with some others.

4. The Ram system, comprising the machines made by Schwarzkopf and by Warsop.

The principle upon which the whole of these percussive drills act is that of the steam cylinder and piston of an ordinary steam engine. The piston is moved rapidly backwards and forwards by compressed air (usually) or steam, as the case may be, and in doing this strikes the blow upon the rock by means of a chisel or drill, which is attached to the piston-rod. Care is taken, in regulating the supply of the air or steam into the cylinder, that a portion of the inflow shall form a cushion that prevents the piston striking against the cylinder.

The variations in the different patents and inventions consist

of special arrangements by which the chief end is accomplished.

as well as for turning the drill around as it works, and in

lengthening the machine, or so altering its position, as to adapt

the blows to the ever-increasing depth of the hole.

Y 2

324 Metalliferous Minerals And Mining.

This being the principle on which the whole of the drilb act, and these the objects of the various arrangements of detail, I may, without expressing a preference for any one of the best known drills, illustrate the mechanism of them by means of Mr, R, Schram's detailed figure (fig. IJ9) of his rock drilling machine, and by Mr. Schram's explanation of the same.

' Schram's machine consists of the following moving parts : i. the main piston ; ii. the slide piston and slide; iii., the rotating movement with its piston. The accompanying fig. IJ9 shows a longitudinal section of the machine.

'When the piston d is in the position shown in tig. 139, air,' on the cock being opened, enters the cylindeT c through the port f>, and pressing on the lower end of the piston d, forces it backwards, causing the backward stroke. As

Fig. ..i).-M™*H oFScHHAii's Rock goon 35 the pistOn d has

TTir machine cnn be worked cither conipres-ed atr or bv st.iin.

Construction Of Rock Drilling Machines. 325

passed the port e, the air rushes through that port into the small cylinder £ (in the slide box). At this moment, when the air presses upon the upper end of the slide piston /, the cylinder k, in the opposite end of the slide box, is in communication with the outlet s through the port /, and the circular hollow in the piston rod r; consequently the slide piston with the slide is moved downwards, so that the passage A is opened for the admission of air from the slide box, whilst the lower end of the cylinder through the port d now communicates with the outlet s. The air now entering the cylinder through the opened port A, presses on the upper end of the piston, forcing it forward, and thus causing the drill, carried in a socket at the extremity of the piston rod, to strike with the impetus of its own weight and all the power of the compressed air against the rock. As soon as the piston d has passed the port /, air enters through it into the cylinder Jk, At this moment the cylinder g communicates with the outlet s through the port e and the circular hollow r in the piston rod, and the slide piston with the slide is moved back into the same position. Meanwhile the piston has completed its stroke ; the cylinder is, through the passage A, in communication with the oudet s ; and compressed air again rushing through the re-opened passage causes the action just described to be repeated so long as the supply of motive power is kept up.

' It is an important feature in this machine that the slide rod /is made in the form of a double spindle valve; by this method of construction it remains in position, without any recoil, until the piston d has made the greater part of its stroke.

' As in some varieties of rock it happens that the drill often sticks fast, there is a reversing rod / to suddenly reverse the slide, and thus pull the drill out of the hole.

'With careless workmen it would frequently happen that the piston would strike against the lower cylinder cover, therefore there is an air cushion at the lower end of the cylinder. In addition to this there are an iron ring and an india-rubber washer (exchanged for one of wrought iron when steam is used), with the object of moderating the violence of the shock such blows, inadvertently permitted, would cause.

326 METALLIFEROUS MINERALS AND MlNINO.

*In order that the hole drilled be perfectly round, it is necessary that the cutting tool should partially rotate at each backward stroke, so that its cutting edge shall every time strike the rock in a fresh place ; but in order not to lose any power, it must always make its forward stroke without rotating. For this purpose a twisted bar o is employed, connected with a grooved disc /, and a brake acted upon by a small piston /. Communicating from the slide box with the cylinder n is sl small port m, by means of which the compressed air exerts a constant pressure upon the upper end of the piston /. When the main piston d makes its backward stroke, the cylinder is in communication with the outlet, and consequently there is no pressure on the lower end of the piston /. The constant pressure on the upper end of this piston, therefore, now presses it upon the brake which presses upon the disc p, preventing it from turning, and thus the main piston //is forced to partially rotate roimd the twisted bar o secured to the disc But when the main piston makes its forward stroke, and steam or compressed air fills the cylinder c, the motive fluid enters through the small ports u and presses on the lower end of the piston /, thus counterbalancicig the constant pressure on the upper end. There being now no pressure on the brake the disc / is free to rotate, and the piston d makes its forward stroke without rotating, partially turning the disc as it proceeds by means of the twisted bar o,'

The machines used underground are worked by means of air, which on the surface is compressed to several times less its own bulk, and equal to a pressure of from 60 to 90 lbs. to the inch. The air is stored in a receiver, from which it is conveyed underground to the drill by means of wrought or cast iron pipes, of sizes suitable to the number of drills worked, pipes inch diameter being equal to the supply of one drill, with which it may be connected by a strong flexible hose, as shown in fig. 130, which represents an Ingersoll drill at work in a mine. The compressors are as various as are the drills, but the object to be attained is the same, whatever shape is adopted or arrangement of valves is used About one third of the power

The Compression Of Air. 327

derived from the compression is lost in the transit, and this loss must always be taken into account in providing the amount of air required.

The power by which the air is compressed on the suriace is generally steam. Ordinarily 50 lbs. pressure of steam will obtain 90 lbs. pressure of dr in the receiver, and it is estimated that a boiler of lo-borse power is equal to driving four or five drills. The amount of heat generated in the effort to compress air is very great, and the compressor has to be kept cool by water chambers, with which it is provided!

The same results may be obtained by the use of water wheels, or turbines, of sufRcient capacity and strength.

The appliances on which the drill is fixed are very varied, from a movable frame on wheels to a simple stretcher screwed horizontally or vertically across a level, as shown in fig. 130.

Drilling by machinery is as yet in its infancy, and it is perhaps too soon to judge of its cost in comparison with hand labour. Miners will have to grow up accustomed to the handling and working of the machines. So far as appears from a comparison of costs which I have made, I think we may at

328 Metalliferous Minerals And Mining.

present depend upon getting the work done at three- fourths of the cost of hand drilling ; while, as the rate of prepress is eight times as fast, a great saving will be effected in costs of management and other fixed expenses. We have not, however, as yet attained the minimum of cost in machine drilling operations.

The specialities of the different drills I have named will be

best learned from the descriptive and illustrated circular issued by th:ir makers. They are all doing good in various parts of the worid in mining and engineering operations, and it is only by a comparison of their respective merits that the .."cader can judge of their adaptation to any particular kind of work.

ROCK-DRILLS IN USE. 32g

In the North Wales and Shropshire mining districts, where I write, an adaptation of Beaumonfs drill is doing good work at the Halkyn Deep Level. Darlington's simple and effective machine and compressor is working well at the Minera Lead Mine. At the New Crickheath Lead Mine an Ingersoll drill is canyiog a level forward at the rate of la yards a week ; and

Fin. tji,— HtcHAHTSu or Joidah's Rornc-Diiu.

at the Roman Gravels Lead Mine an Eclipse drill is workuig satisfactorily in one of the deep levels.

The cost of steam engine, compressor, receiver, pipes, and drill amounts to a large sum, which, while its expenditure is not felt in an established and successful mine, or in a mine starting with a good capital, is a good deal to expend in the

330 Metalijferous Minerals And Mining.

ordinary class of mining operations. Attempts have therefore been made to construct a machine that shall utilise and intensify the strength and labour of two or three men, by the aid of mechanical appliances. One of these is the Hand Power Rock Drill ' of Messrs. Jordan, Son, & Meihe. This drill is shown at work in fig. 131, and the construction and working of the machine will be understood by a reference to the section of it given in fig. 132. c is an air-tight cylinder in which the piston L works by being forced up and down by the action of the fly-wheels upon the cams k k ; when the piston is raised, the air above it in the cylinder is compressed into much less than its ordinary bulk. This compression forces the piston downwards as soon as it is free, and thus strikes the blow. G is the drill bar fixed within the piston, and by a simple arrangement of screws and bevil wheels at d, e, and b, this bar, every time it strikes the rock, is partly turned around, and so lengthened to follow the deepening hole, besides doing its work more effectively.

About 150 blows of from 130 to 160 lbs. each can be struck per minute, the progress made being from 40 to 70 inches per hour, according to the nature of the rock, or quite four times the ordinary rate of progress.

Another hand drill is the Victor, in which the drilling tool is lifted up by cams, as in Jordan's, and is forced back by a spiral spring. A more recent invention by Faber, of Barmen, Prussia, causes the spring to be pulled up as the drill is lifted by the cams, the spring when released quickly pulling the drill down again, and so giving the blow.

We still want a cheaper and more portable machine for working in stopes. It need not do its work so quickly, and yet save a great deal of manual labour and much cost

Chapter Xxxv.

On The Working Of Metalliferous Mines—

Continued,

Explosives — Gunpoiwder — Compositions of Various Kinds — Principle of Explosion from Nitro-glycerine — Dynamite — Lithofracteur — Tonite — Gun-cotton — Patent Gunpowder — Explosion by Detonators — Saying that could be effected often prevented by Miners — Plan adopted in American Mines — Danger — Firing by means of Electricity.

Explosives. — Gunpowder, — The actual discovery of gunpowder is lost in obscurity. The Chinese claim to have used it long before it was known in Western Europe, where its discovery is assigned to Berthold Schwartz. An explosive powder was known in this country and used for heavy cannon in the eleventh century ; but it was not until the thirteenth century that its composition became more accurately defined and its power imderstood. It was not until three centuries later that powder was used in mines as an explosive, when Martin Weigal first proposed its use in the mines of Freiberg in the year 1613 ; but it was not before 1630 that its use became general in the mines of the Hartz and Erzgebirge. Forty years later, or about 1670, it was first used in England at the Ecton mines, on the borders of Stafford and Derby, when it was used not so much to break down the rock underground as to split up great blocks of stone which had been brought down by the old methods of fire and wedges. Early in the eighteenth century it was introduced into the mines of Western Cornwall by two men named Bell and Case, who came from the Eastern coast, and who had learned the secret from the Germans. Since that date its use has become almost universal in mines,

332 Metalliferous Minerals And Mining;

and until very recently it was the only explosive ordinarily used.

The composition of ordinary gunpowder as made in different countries is as follows :

Nitre

Charcoal.

Sulphur

England

France Germany

China

75 -o

lO

12*5

75 -o

lo-o 100*0

lOO'O

100 -o

The power of powder, and indeed of all the explosives to be described to rend asunder the substances in which they are enclosed, depends upon the setting free the moment they are ignited of those enclosed gases, which are increased manytimes the bulk in which they lay in the constituent parts of the powder. The more instantaneous the ignition of the whole mass the greater the rending force ; hence the superiority of explosion by detonators over simple ignition. M. Berthold, a French chemist, estimates the relative explosive force of the different kinds of powder, and of substances which form the base of other explosive compounds, as follows :

Blasting powder

Artillery powder

Powder with a base of nitrate of soda . Powder with a base of chlorate of potash

Gun-cotton

Gun-cotton with chlorate of potash Nitro-glycerine

Berthollet, a French experimenter, endeavoured, towards the close of the last century, to increase the force of blasting powder by the use of chlorate of potash as a base, but the destruction of his works, workmen, and part of his family, with the miraculous escape of himself, by an explosion caused by his striking his cane on a grain of powder lying on the floor, put a stop to his experiments.

Since that time various experiments have been made in the

Nitro-Glycerine. 333

same direction, and compounds have been introduced as safe and powerful, but the extreme danger attending the manufacture, carriage, and storage of such compounds has hitherto prevented these chloratic powders from coming into general use.

There are variations of black blasting powder now in use. For example, Messrs. Curtis and Harvey make a very strong and safe explosive. There is also the powder called /w/Zn?/////, whose properties are at present, however, little known.

Nitro'glycerine, — The discovery of nitro-glycerine by M. mining explosives of the most wonderful power. Nitroglycerine itself is formed by the action of nitric and sulphuric acid upon glycerine. This is a thick, syruplike-looking liquid, with a sweet taste, that is obtained chiefly from the fatty substances used in the manufacture of soap and candles. When, by the action of the acids named, it becomes nitro-glycerine it is an oily liquid like olive-oil, with a sweet and rather aromatic taste, but without smell. It is poisonous when taken into the stomach or absorbed through the pores of the skin. Its vapours when exploded cause violent headache. It explodes at a heat of about 360° with great force, which it also does if struck with a hammer. Even the blows made in unpacking the wooden cases in which tins containing it have been packed have caused terrible explosions.

In exploding, nitro-glycerine gives out twice the amount of heat generated by gunpowder. It has therefore been calculated that if a volume of powder gives 200 volumes of cold gas expanded by heat four times to 800 volumes, a volume of nitro-glycerine gives 1,300 volumes of cold gas, which expanded by heat eight times produces 10,400 volumes. Its explosive power is consequently about thirteen times that of powder.

Practically, it has been found that the use of nitro-glycerine in this unmixed and liquid form was attended with such extreme danger that it could neither be used, carried, or stored with any degree of safety. The attention of scientific men was,

334 Metalliferous Minerals And Mining.

therefore, long directed to the devising of some means wheitby it might be safer to handle and use, without losing much of its explosive force.

Dynamite, — As one of the first outcomes of these efforts was the invention and manufacture of this explosive by Mr. Alfred Nobel m 1867. Dynamite, which is also known and extensively used in America as Giant Powder, is stated to be a mixture of nitro-glycerine with an infusorial earth, that consists principally of the minute porous silicious shells of the Diatomaceae.

It is of a greyish brown colour, and it freezes or congeals at a temperature of 43° Fahr. It is claimed for it that it is as safe as ordinary powder in the handling ; that small portions of it may be exploded by a blow ; but packages containing it may be freely handled. It must be kept dry, but it may be used in wet groimd. An American mining captain thus sums up the advantages of its use as compared with ordinary powder' :

I St. The amount of work which can be performed in a given space in a mine is nearly double.

' 2nd. The consmnption of steel is about one hal£ ' 3rdL The consumption of hammers is about one half. ' 4th. The consumption of candles is about one half. ' 5th. The width of drifts or stopes is only about one half, requiring so much less material to be hoisted from the mine.

6th. The mining timbers required are much shorter.

7th. The ore raised firom the mine is broken by the force of the powder, so as to require less spalling for the mill.

8th. The progress of the work in the mine is expedited at least 40 per cent, and in wet mines the progress is increased fully fifty per cent, if not more.'

The yearly consumption of dynamite is now very large in all mining countries.

Two variations of dynamite have recently been introduced. ]''irst, its explosive power has been increased by issuing it in a

1 Raymond Statistics of Mining West of the Rocky Mountains,

Lithofracteur. Tonite. 335

more liquid stte ; and, secondly, its safety has been increased at the cost of some reduction in its explosive force, by the addition of camphor.

IMhofractmr, — This is the name given to another very valuable adaptation of nitro-glycerine, as invented and patented by Messrs. Krebs Bros., of Cologne, who have agents in the chief mining districts of this country. As far as may be surmised, this explosive differs from dynamite in the use of a less proportion of nitro-glycerine, and the use, as absorbents, of substances which are explosives themselves, instead of a nonexplosive, as infusorial earth. The result is said to be more powerful than that of dynamite ; the use of it to be quite as safe; and the fumes, when exploded, less noxious than those of from the fact that the whole of the nitroglycerine in the compound is consumed. I do not pretend to decide these points, but that it is a most valuable and powerful explosive I have no doubt, as the following examples of work done by it, and witnessed by myself, will show :

The bed of mineral to be won was about one foot wide. It was underlain by several beds of hard limestone, which had to be blown down to a width of about 3 feet before the mineral bed could be blown down. A one-inch hole was drilled in the solid limestone, in the face of one of the stopes. The hole was placed 4 feet 6 inches above the underside of the stope, and it penetrated the limestone 3 feet. This hole was charged with 12 ounces of lithofracteur. The whole mass of the limestone, 3 feet wide, 4 feet 6 inches deep at the face, and from the end of the hole irregularly downwards to a total distance of 6 feet 6 inches, was detached and broken, so that it was worked down with a pick. Another charge of 12 ounces brought down bodily a mass of the limestone on the face of a stope, 4 feet loig 3 feet wide, and 3 feet deep. Two other charges gave similar results.

Tonitey or Cotton Powder is another powerful explosive. It seems to be a mixture of nitric acid, with cellulose substances, cotton woody fibre, hemp paper, and the like. It is held by its makers to be the ' safest, cheapest, and strongest of all explo-

336 Metalliferous Minerals And Mining.

sives/ which is, of course, saying a good deal. In experiments that were made at Messrs. Clayton and Speight's collieries, near Leeds, in June 1877, Mr. Dineen explained that tonite is of a different nature to dynamite or gun-cotton. It contains no glycerine, and it will not explode except by means of a detonator specially prepared.

Gun-cotton closely allied, however, to tonite, is the older explosive gun-cotton, and also the explosive recently manufactured by the Patent Gunpowder Company, at their works in Glyn Ceiriog, North Wales, from woody fibres.

Improvements have lately been made whereby the cellulose by being soaked previously in sulphuric acid, is reduced to a fine impalpable powder, in which it is in the best state possible for the absorption of explosive liquids, and the improvements will affect all those explosive compounds in which cellulose matter is used.

Besides the compounds I have described there are a great number of adaptations of nitro-glycerine and nitric acid, with cellulose and other matters. The science of explosives is probably yet in its infancy, and possibly we may hear before long of explosives safer suid stronger than any yet discovered. Happily the reversal of the judgment given by Mr. Justice Fry in June 1877, which practically gave to Nobel's Explosive Company the exclusive control over nitro-glycerine compounds, leaves the field of discovery and manufacture open, which otherwise it would not have been.

Detonators, — The whole of the nitric acid and nitro-glycerine preparations just described require to be exploded by a detonator, which is usually a cap partly filled with fiilminating powder, which, when the fuze has been fixed in it, is placed in a small cartridge, probably itself more explosive than the bulk of the material. The fiize is hghted in the ordinary way.

Since the above has been in type, Mr. Justice Fry's judgment of 1877 has been confirmed ; consequently, lithofracteur cannot now be sold or used in this country. Practically, and apart from the legal aspects of the case, this is a misfortune to mining, and it is to be feared that improvements in nitro-glycerine explosives will be impossible for some years to come.

Firing By Electricity. 33/

The great danger to the miners lies in unexploded charges, and here the greatest care must be taken. The Government rules are very stringent, and should be implicitly obeyed. The instructions given by the makers of the different explosives should also be closely adhered to.

There is no doubt that the explosives just described are as safe as ordinary powder, and that they will, if the holes are placed with judgment, do several times the work of ordinary blasting powder. But we want a new generation of miners before these explosives will perform all the work they are capable of. It is found, I think, that the men will, if not watched, persist in placing the holes just in the way they did before, and bring no more rock down at a charge than they did with the old powder. They are more intent on saving the powder than of bringing down plenty of ground.

To obviate this, the plan has been adopted in some American mines of appointing one or more intelligent firemen, whose work it is to direct where the holes are to be drilled, and to fire the shots. The men are paid so much per foot for drilling. When the holes are deep enough the depth of them is measured, and the drillers are removed to another part of the mine. The firemaii then charges the holes and fires the fuze. Then the fillers come and remove the stuff, and the process is repeated.

Firing by Electricity, — Efforts have been made, since the days of Franklin in 1757, to supersede the ordinary method of igniting explosives by means of fiize, by the explosion of such charges by means of electricity.

For some time past our Government, as well as others, have, under the advice and by the help principally of Mr. Bell, largely adopted this method in large quarry operations, and in the firing of trains or torpedo-hke machines.

Recent attempts in the application of the tem to quarrying have also been successful ; and the operation is valuable in the sinking of shafts, because it can be performed on the surface after the miners have come out of the pit

The principle is simple. Instead of fuze double wires prepared for the purpose are inserted in the explosive charge,

z

338 Metalliferous Minerals And Mining.

When a number of charges are to be exploded, one wire from one hole is securely attached to one wire in the next hole and so on, the circuit being made complete through all the chaiges. The electricity may be excited by an ordinary electrical machine, although there are now some specially prepared for the purpose. When a sufficient quantity is stored the cu-cuit is completed to the machine, and the whole of the shots are simultaneously fired.

Good illustrations of the method are given in a pamphlet on Bamhardt's Electrical Firing Machine, which is issued by Mr. John Darlington, of 2 Coleman Street Buildings, London, E.C.

Applied to quarries, open workings, large shafts, and work mgs where there is plenty of room, the method will be found advantageous in many respects. But the care required is so great, the risks of failure numerous, and success is so dependent upon delicate and intelligent manipulation, that I fear it will be some time before we have miners sufficiently intelligent, skilful, and patient to manage the process.

Chapter Xxxvi.

On The Working Of Metalliferous Mines

Continued,

]!)rainage and Pumping—Ancient Methods—Barrels — Hand Whims — Horse Whims— Water Wheels— Newcomen's Engine— Watt*s Engine- Saving effected in Fuel — Register of Duty, 18x2, 1844, 1878— Tables of Work done — Improvements, resulting in Increase of Duty, in Boilers, Engines, Shaft Appliances— General Description of Pumping Arrangements in a Shaft— Other Pumps — Hydraulic-power, Windmills— Great Tunnels for Drainage— Blackett, Halkyn, Redruth, Kit Hill, Ernst August Rothshonbergen, Emperor Joseph, Comstoc!:.

Drainage and Pumping.' — One of the first, and usually the chief, difficulty encountered by the miner lies in the presence of water, whidi, finding its way firom the surface through chinks and crevices of the strata, or through strata porous in itself, rapidly accumulates in underground excavations.

The difficulty increases as he passes below the adit, short, driven for the purpose of draining the superficial strata. The old book on mining by Agricola, already referred to, contains many illustrations of the rude contrivances employed up to his time to overcome the inflow of water. 280 years ago few mines in Cornwall were worked at a greater depth than from 30 to 40 fathoms. The drainage machinery then employed was of much the same character as that described by Agricola, for, we are told by Carew,* it consisted of 'pumps and wheels

John Bourne, Treatise on the Steam Engine Longmans ; Warrington W. Smyth, Coal and Coal Minings Croshy Lock wood & Co.; S. HugheSj Water WorJb, 6£-., Crosby Lockwood &. Co.; Husband, 'Lecture on Pumping Machinery,' Mining journal, June 22, 1878, et, seg,

(arew, Survey of Cornwall 1602.

Z2

340 Metalliferous Minerals And Mining.

driven by a streame and interchangeably filling and emptying two buckets, with many such like.' Towards the middle of the last century, a good deal of water was raised by hand and force pumps. For mines of shallow depth, water barrels, worked up and down the shaft by a windlass, and in mines of greater depth by a horse whim, were employed. A common device, and one still practised in the East, was the rag and chain pump, which consisted of a chain, on which was tied at intervals a bundle of rags, working up a pipe, up which the rags brought the water from the bottom to the top.

One of the deepest mines at that time was the Buller Garden Mine, and in 1778 it was 90 fathoms deep, and was unwatered by means of an engine shaft extending to the bottom. In this shaft there were two pmnping fire-engines,' raising the water from the sump to the lower adit, a height of 67 fathoms.

Surface water was early utilised in Cornwall and elsewhere for turning large water wheels, which wore made to work pumps. A wheel at Cook's Kitchen Mine, at the date just given, being 48 feet diameter. It worked tiers of pumps of 9 inches bore, divided into four lifts, and raised water 80 fathoms to the adit Its power was calculated to be equal to a Newcomen's improved fire-engine of 47-inch cylinder. Water wheels still do good service in pumping where the water supply is ample, some of them being of great size ; the drawbacks to their successfiil working being drought in summer, and long-continued first in winter.

Newcomen's fire-engine, which was introduced about the year 17 10, underwent many improvements up to 1780; but about that date the quantity of coal consumed by an engine of good size amounted in value to 3,000/. yearly.

From 1770 the improved engines of Watt gradually came into use ; the terms on which the inventor let them being the payment to him of one-third the value of the coal saved over the amount consumed by the old Newcomen engines.

This was very great, for we find that at Chacewater Mine,

Pryce, Mimralogia Comubiensis.

Pumping Power Of Engines. 34I

the saving in the fuel consumed by three engines amounted to 7,200/. a year.

An ingenious mechanism had to be attached to the beam of the engines to register the number of the strokes made and the length of the strokes ; a record being also kept of the consumption of coaL When Watt's patents died out, this registering of work done fell for a while into disuse ; but about the year 181 2 the practice of registering the duty performed by the engines and the expenditure of fuel was revived, and placed under the charge of the late Captain Lean, and the work, as far as it relates to the best engines, has up to this time been continued by his son.

The duty of an engine is the amount of work done in relation to the amount of fuel consumed. The method adopted in Cornwall has been to find out what weight of water has been lifted one foot high by the consumption of a bushel=:94 lbs. of coal. Of late years the bushel has been exchanged for the hundredweight of 1 12 lbs. This found out, the ascertaining the weight of water lifted out of a mine of a given depth, is simple. Thus, if an engine, by the consumption of 112 lbs. of coal, lifts 60,000,000 lbs. of water i foot high, the amount raised out of a shaft 100 fathoms, or 600 feet deep, would be 100,000 lbs. This being the result of dividing the amount raised i foot high, by the depth of the pit, 600 feet.

The highest duty reached by any of Watt's engines was 24,000,000 lbs., but by frequent improvements in their construction, and in the arrangement of the pumps, the amount gradually increased, until in 1844 the average duty performed by 37 engines was 68,000,000 lbs. of water raised i foot high by the consumption of 112 lbs. of coal, or a consumption of lbs. of coal for every effective horse-power. In March 1878 the average duty had declined to 49,000,000 lbs. or lbs. of coal for every horse-power, or an increase of quite 25 per cent, on the cost. In June of the same year, the duty performed had increased, being as follows :

The number of pumping-engines reported for this month was 16. They consumed 2,116 tons of coal, and lifted 16' j

342 Metalliferous Minerals And Mining.

million tons of water lo fathoms high. The average duty of the whole was, therefore, 52,400,000 lbs. lifted i foot high, by the consumption of 1 12 lbs. of coaL The following engines exceeded the average duty :

Dolcoath— 85 in 58-8

Mellanear — Gnndry's 80 in 56 '2

West Basset — Thomas's 60 in 55*9

West Wheal Frances— 58 in 55-3

West Tolgus— Richard's 70 in 57*0

West Wheal Seton— Harvey's 85 in. . . . 72*1

West Wheal Seton— Rule's 70 in. ... 75-4

Still there is a decline of pumping power compared with 1844, and a variety of reasons have been assigned for the falling off— such as the use of inferior coal, less carefully trained stokers, and working the engines with less expansion of steam than formerly; but perhaps the chief reason lies in the fact that the mines are, on the whole, three times their former depth, or 300 fathoms instead of 100 fathoms. The greater depth, of course, entails a greater length of pump rods, and correspondingly more friction.

The useful table on pp. 338-9, compiled by Mr. J. B. Simpson,* presents in a very complete form the work done by 12 different engines, together with the cost of the same.

Assuming that my readers understand the principle on which a pump acts, fig. 133 will represent the ordinary pumping arrangements in a mine shaft. Fig. 134 is a continuation of the same as in a section at right angles to 133 up to the surface.

It will be seen that the water is drawn first of all from the sump through the suction pipe i by means of a bucket with valves working in the barrel 4, and is forced up from thence 80 yards or so to the plunger arrangement at 6, 7, 8, and 9. From this point upwards, plungers, which consist of a solid piece of iron, 8, working in a barrel or cylinder, 9, are generally

Simpson, Transaciions of North of England InstUnte of Mining and Mechanical Engineers vol. xix. p. 201, et seq.

Improvements In Steam Engines. 343

used in preference to the bucket and valve arrangement at 4, for the reason that the water does not by the adoption of this means need lifting. The weight of the rods 12, 13, or as much of this weight as is necessary, forces the plunger 8 down, which in its turn sends the water up the adjoining pipe, a, to the next plunger, and so on up to the adit level or other point of discharge, a valve placed near the point 10 preventing the retiun of the water downwards. The weight of the column of water in the pipe is thus balanced by the weight of the rods. The extra weight of the rods above what is required for this purpose being balanced by the erection of x bobs in short levels driven at convenient points in the shaft

Compared with what was done sixty or seventy years ago, it will be seen that pumping-engines do now about three times the work they did then. This result has been accomplished by means of improvements (i) in the construction of boilers ; (2) in improvements of the engines, particularly in the arrangements about the cylinder ; and (3) by the superior mechanism of the pumping arrangements in the shaft itself The boilers have been made stronger ; Taylor's boilers, for example, being of an inch thick and equal to 60 lbs. pressure. Then, in Cornish boilers, by the arrangement of flues running through them, a larger surface of water is exposed to the direct action of the fire. The same result is attained in tubular boilers. In the engine there is the expansion of the high-pressure steam, which is effected by cutting off the supply when the stroke is only about a quarter made. There is also the addition of an outer case to the cylinder, which, when filled with steam and cased by a covering of non-heat-conducting materials, preserves the heat of the cylinder itself. Then in the shafts great attention has been paid to the construction of the pump rods, so as to provide strength without the addition of weight or friction. The latter is also avoided by the free use of rollers, especially in inclined parts of the shafts, as well as by the nice adaptation of balance bobs; so that a great engine lifting up a vast quantity of water now does its work easily and smoothly.

Thus far the pre-eminence must be to Cornish

Comparative View Of The

s

z

Kind of engine

.a

"iS"

1S.S

Con,ihEgLD..

ins.

ft. in.

ft. in.

1. Do. (iBucktt

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r 35.o4

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:

Duty Of Pumping Engines.

fi

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d

a

u

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lbs. 22*7 14916 184-5 35*34 80-7

X3'4i

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2fi*8

22*67

ai-47

8x*86

161*65

50'zo

39*34 69*29

58*73 43'65

87*43

202*94

61*76

35 'o

114'a 82*0

70*0 7136 79-98

a

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5*66

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67*42 84*9

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37*4

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10*9

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No. and

description

of boilers

19*69

X3i36a

22*63

9*oz

7*78

8*02

151,694

59,564

53.5*3

32*95 151,959

20*81

X7*22 120,527

a Haystack

4 Common

2 Cornish

2 Common

Juke's patent

fire-bars.

4 Common

Cornish

3 Common

2 Cornish

3 Common

3 Cornish

13 "05 86,953 3 Common

Size of boilers

h a

igs.

' 34 ft by 6 fL 9 in.

tube 4 ft. 3 in.

f X4feet ) I diam. J

f 31ft. )

diam. )

30 ft. lon2,6ft.

diam.

tube , 3 ft. 3 in.'

30 ft. lonk{,6 ft. . diam.

( 30 ft. by )

I 6 ft. [

30 ft. by

6 ft

tube

, 3 ft. 3 in. .

( 30 ft. by

30 ft. lon,6ft.

diam.

tube ,3 ft. 3 in. j

30 ft. ) lon,6ft.

diam. ) 34ft.by 5 ft. 9 m.

tube 3 ft 3 in.

- Ion .',5 ft. [ diam J

a33

34

az43

h

346 Metalliferous Minerals And Mining.

mu

1*1

The Utilisation Of Wind Power. 347

engineers for getting the most work done by their pumping engines for the least money — although great results are attained in the North of England Besides the pumps I have described there are the useful pumps of Tangye, another of Haywood, with the recent invention of Daveys, manufactured by Hathom, of Leeds ; but for deep mines and large inflows of water the old pumping arrangement must remam. Efforts may however be made to increase its power by the use of stronger boilers and more perfect engines and machinery.

Efforts are being made to utilise surface water for pumping and winding by means of hydraulic apparatus, a high thin column of water in a shaft being made to throw up a larger column a lesser height For an interesting account of work done, chiefly in Germany, the reader may consult a paper by Mr. John Darlington, in tfie Report of the Miners' Association of Cornwall and Devon for 1874.'

Dr. Raymond' suggests that for high, dry, and remote districts, like those aboimding along the Sierra Nevada, . windmills may be used with success in mining operations ; and certainly there is room for experiments in this direction. The windmills of Norfolk and Holland, particularly those of the latter country, have done good work in surface draining, and there does not seem any reason why the adaptation of this power might not be applied to the working of mine pumps and the movement of ore stamping and dressing machinery. As a matter of fact, too, windmills have been used for mining a century or two bacL In 1708 they were used at several collieries in Scotland for pumping. On an old map of the Mona Copper Mine in Anglesea, dated 1785, a windmill is shown in use. At the same mine one, constructed by Captain Hughes, is now working well Windmills were also occasionally used half a century ago at some of the Cornish mines. Not long ago one was used at a lead mine in Flintshire, for dressing the ore. Another has been in use several years at the Rosebush Slate Quarries, in Pembrokeshire ; and one has just been erected by Captain Davies, at the Clogau Gold Mine, Merioneth-

StatisHcs of Mining West of the Rocky Jlfonniains,

348 Metalliferous Minerals And Mining.

shire. The great defect of this source of power is its intermittent action; but in some instances this is overcome by utilising the excess of power possessed at times to pump water from a lower to a higher level, where it is stored for use on calm da3rs. At the present time attention is drawn to this question, and the mining papers have numerous references and suggestions relating to the subject

Notwithstanding the immense power of the engines employed, varying as they do from 800 to 1,000 horse-power, it has been found practically impossible to drain some mines, especially those in limestone regions. Thus an 800 horse-power engine was found unable to unwater the Rhosesmor Lead Mine in Flintshire, and an 85 -inch cylinder engine was comparatively powerless at one of the Derbyshire mines in the same formation.

Those of my readers who have seen Holywell, where a river able to work mills and manufactories rushes from underground, may form some idea of the volume of water that has often to be contended with in limestone regions. One consequence of this flow of water is that in Derbyshire it is found impossible to work the lead mines below the level of the old ' soughs,' or adit levels which have been driven, and at this moment some known productive mines are idle in Flintshire from the same cause.

These considerations, with the expense also that is entailed by pumping from deep mines, have led, where the country lies high above the sea, and the contour of the surface is favourable, to the construction, at a great cost, of long capacious district tunnels.

One of these in this country is the Blackett level, commenced by Mr. Beaumont, on his property in East Allendale, in 1850, and whose entire length is nearly seven miles. The Halkyn drainage level, which, under the superintendence of Messrs. John Taylor & Sons, is now progressing at the rate of 80 yards a month, starts from a point between Flint and Halkyn, and will extend to the neighbourhood of Mold. This will be about seven miles long, and it will drain the lead mining

Long Tunnels. 349

region of Halkyn Mountain, including the Rhosesmor Mine just alluded to. In the mining district of Redruth, in Cornwall, there is a tunnel which, including its branches, has a length of nearly forty miles. The Kit Hill tunnel, in the same county, is another similar great work now in course of construction.

In Germany there is the Ernst August tunnel, which was begun in 1850, at a place near Gittelde, in the Duchy of Brunswick, and which extends a distance of fourteen miles to underneath the town of Clausthal in the Hartz, where it drains the mines to a depth of 1,200 feet below the church of that town.

The Rothshonberger Stollen, a tunnel near Freiberg, in the Erzgebirge, is eight miles long, and with its branches much longer; and a tunnel twenty-four miles long is in contemplation in the same district.

The mining district of Schemnitz, too, in Austro-Hungary, has a level, The Emperor Joseph,' more than nine miles in length. The Comstock tunnel, in Nevada, is another great work, just now completed, as far as the main level is concerned, and an idea of the magnitude of this work will be gained by a reference to figs. 39 and 40.

These great works can, however, at the most only drain down to the sea level, and if the metallic ores contained in watery strata below this level, and which hitherto have been deemed unattainable, are to be won, stronger and more effective means than any hitherto known must be conceived and adopted. Here is a field for engineering enterprise, for we must not be beaten. We are bound ultimately to win.

Chapter Xxxvii.

On The Dressing Of Metallic Ores,

Picking and Sorting — Crashing with Hammers— Spoiling — Ore-breaking Machines — Blake's, others — Stamping and Stamps — Old Cornish Stamps — Improved Stamps — Work done by them — Work done by American and Australian Stamps — Recently invented Stamps — terson's Elephant Ore Stamp — SholPs Pneumatic Stamp — Husband's Stamp — Harris's Annular Stamp Head — Cox's Stamping Machine.

When brought out of the mine, metallic ores are usually more or less intermixed with each other, and with the various nonmetallic substances in the midst of which they lay when in the lode or deposit They have therefore to undergo various processes whereby they may become separated and concentrated to as good a marketable quality as possible.

I will now notice these processes in the order in which they occur, together with the principles on which they proceed. In doing this we will assume that we are following the processes employed in the preparation of lead ore, and we can turn aside, as may be required, to notice the variations of the processes as adapted for other metallic minerals.

Picking and sorting. — When lead ore is brought out of a mine, it is tipped over a strong grate, where a stream of water is generally caused to pass over it The purest lumps of ore, which do not require further dressing, are here picked out, as are also stones known to be barren of ore. In the caverns and flats of the Carboniferous Limestone there are often great lumps of pure galena, which only require the clay chipped or washed oflf them before they are ready for sale.

Ore Crushing. Stone Breakers. 351

Crushing, — All the lumps containing ore are placed on one side to be crushed, or otherwise broken into sizes suitable for the next operation.

The means formerly used for this purpose were very simple. The larger lumps were broken by heavy hammers, and still further reduced in size by spalling. This was an operation in which the lumps of ore were laid upon a flat bench of stone or iron, and struck with a large flat piece of iron fixed on the end of a handle of wood. In course of time a pair of rollers turned by the hand were also used in reducing the ore to its requisite fineness, otherwise it could by constant spalling be reduced to the same size. The process is still in use at mines where machinery has not been erected, and I saw it in operation in 1878 at a lead mine in Flintshire, which was returning 40 to 50 tons of ore per month.

More recently at extensive mines this first crushing and breaking of the ore has been better and more expeditiously performed by machines constructed for the purpose ; the one known as Blake's Stonebreaking Machine, the invention of Mr. Blake, of New Haven, and manufactured in this country by Mr. Marsden, of Leeds, is the one in most general use. Latterly there have been modifications of this machine, which are known as the Alden, Archer's, Broadbent's, and Lester's. Blake's may be taken as the t3rpe of the group, and a representation of it is given in fig. 135, and the following description by the maker will enable the reader to understand its mechanism :

' The sectional elevation shows the position of the essential parts of the stone-breaker, a is the main framing, and b a soft cast iron plate interposed between the frame and the fixed jaws and c. In place of the tedious process of running white metal behind the jaws, they have now smooth soft metal strips, which form a perfect bearing; the same mode of securing a good bearing is also adopted for the movable jaws, c' c. The sectional jaws are obviously renewable one by one, and therefore derive the name " Reversible." When any jaw becomes worn, it only requires to be turned, and does not, as formerly,

352 Metalliferous Minerals And Mining.

necessitate an entirely new jaw the upper sections which operate first on the stone "sledge" it, and the lower sections finally reduce it to the size desired. The connecting rod is double, and consists of two cast iron heads, G, with capbolts and wrought iron rods, h, keyed into the heads at the upper end, and looped round the steel pin i' at the lower end. The plates k and j are solid, the pins i' and are likewise of steel, and their ends are secured by caps and bolts-to the movable jaw stock d, and to the piece l respectively. From

Fic. 135-— Bu*K's Machikr.

the diagram It will be observed that the latest improvement consists in a modified anangement of the todies and connecting rod, with the object of diminishing friction; and from the results obtained in practice there can be no doubt that, in addition to a saving of power, a far larger quantity of material is treated. The machine has always been acknowledged to secure vast economy, and the long experience which Mr. Matsden has had in the manufacture of the machines, has naturally enabled him to remedy such trifling defects as required to be removed, in order to render the machine perfect.'

Grinding, Stamps And Stamping.

The work that can be accomplished by the different sized machines is thus given :

Sise of machine

Product per hour to road

Maximum power

mouth

metal nee

required

fords

Cwta.

N.Ilp.

Id X 7 12 X 7

Is X 7

15 X 9

20 X 9

24 X 12

24 X i6

32s

24 X i8

30 X 12

It is found that when the ore is laige it is convenient to use two machines, one for breaking the laige and one for the smaller lumps. Practically, also, it has been found that a given quantity of ore, which haa been broken by a machine, may be stamped, when this further operation is necessary, in seveneighdis of the time required for stamping ore broken by spalling, probably because it is fractured throughout

Grinding. — The ore, after passing from the smaller, or from the stone-breaking machine, has to be still further reduced in size. I have said that this was formerly, and to some extent yet is, done by passing the ore through a pair of hand rolls. Ordinarily, now, these rolls are turned by water or steam. The ore is made to pass through them from the machine, and, when necessary, the process is repeated, the ore being brought up again by a wheel, on the inner side of which is a series of elevators, and the rollers being set closer and closer until the ore is of the requisite fineness.

This is the process mostly employed for lead, copper, and zinc ores, but for gold and tin a greater degree of fineness is required, which is attained by stamping.

Stamping and Stamps, — Stamps have been used in Cornwall from early times. These stamps, 280 years ago, were of a simple but effective kind In general appearance they resembled the

A A

354 Metalliferous Minerals And Mining.

kind shown in Gg. 136, and the same descriptioR is in use at some of the smaller mines in the country. They consisted or an upright beam of wood, A, shod with iron, and weighing about 150 This was raised by a wheel, b, on which there were cog-like projections, which when made larger were called cams. The beam was left to fall by its own weight There were generally three or six of these worked togeer by a water wheel The constant idling of the beams crushed the tin ore to powder, in which state it was at first carried away to be further treated This was the diy method. Gradu-

tia. 136.— Old CoMnu Br/utl.

ally the practice grew of turning a stream of water upon the pulverised ore, which washes it through finely perforated iron plates into pits, where it is deposited according to its specific gravity. This is the wet method. In course of time, but not until recendy, the wood beam was replaced by iron, and the weight increased. The bottom of the stamp was also made movable, so that it could be renewed. With these principal exceptions, this was the kind of stamp introduced into California and Australia, any modifications consisting chiefly in the machinery by which it was worked, and the addition of

Work Performed By Stamp Mills.

the rotary process in which the stamp turns around aa it strikes its blows. The first steam stamping mills in Cornwall are said to have been erected at Wheal Fanny in Camborne and Wheal Vor, Breage.

For some time the utmost work done by these old stamps was the crushing of half a ton of ore per head in twelve hours. A modification of them erected at Wheal Basset Mine in Cornwall crushes 27 cwt per head in the same time. At St Ives Consols Mine, a 26.indi cylinder engine worked 52 heads of stamps of 750 lbs. each, besides working a pulveriser, 20 round buddies, and 4 short pumps. The stamps crushed 1,000 tons of ore per month. Among the old stamps was a round one, of a weight of 900 lbs. and a movement of 80 blows a minute, with a drop of 9 inches at each stroke. The cost of pulverising tin ore by the ordinary Cornish stamps is estimated at i. per ton.

The following particulars' will illustrate the amouikt of work done by ordinary stamp mills in America at the present time :

Work recendy performed by stamping machinery in America:

Stanfori> Mill, at White Pine.

Silver Mill Crushit Dry.

Number of mortals . Dischaxge of mortars Number of stamps to each mortar Total number of stamps . Weight of a stamp in pounds Height of drop in inches . Number of drops per minute Screens made of brass wire Trade number of the screens Tons of rock crushed in 24 hours Tons crushed per stamp per 24 hours Quality of the rock . Formation

Fineness of the bullion

Double

Sa

Hard

Mi$wtg Journal, July 28, 1877.

h K2

356 Metalliferous Minerals And Mining.

Meadow Valley Mill, at Piochb.

Silver Mill, Crushing Wet,

Number of mortars 6

Dischaige of mortars Double

Number of stamps to each mortar . . 5

Total number of stamps 30

Weight of a stamp io pounds 750

Height of drop in inches 9

Number of drops per minute 85 Screens made of Russia iron, punched . —

Trade number of screens 6

Tons of rock crushed in 24 hours ... 67 Tons crushed per stamp per 24 hours . .2*07

Quality of the rock Tough

Formation Quartz

Fineness of the bullion 550

Raymond and Ely at Pioche Silver Mill, Crushing Dry

Number of mortars . Dischaige of mortars . ' Number of stamps to each mortar Total number of stamps . Weight of stamps in pounds Height of drop in indies . Number of drops per minute Screens made of brass wire Trade number of screens . Tons of rock crushed in 24 hours Tons crushed per stamp per 24 hours Quality of rock

formation

Fioess of bullion .

Double

Easy Quartz

St, Lawrence Mill, at Newcastle, Placer Co., Cau

Gold Mill, CrusIUng Wet

Number of mortars i

Number of stamps to each mortar ... 6

Total number of stamps 6

Weight of a stamp in pounds 650

Height of a drop in inches 10

Water Used In Stamping Quartz.

Number of drops per minute . Screens made of Russia iron, punched Trade number of the screens Tons of rock crushed in 24 hours Tons crushed per stamp per 24 hours . Quality of the rock

Formation

Fineness of the bullion

2*85

Brittle

Quartz

Eureka Mill, at Carson River, near Virginia City.

saver Mill, Crushing Wd.

Number of mortars Number of stamps to each mortar Total number of stamps . . Weight of a stamp in pounds . Height of drop in inches . . Number of drops per minute Screens made of Russia iron, punched Trade number of the screens Tons of rock crushed in 24 hours Tons of rock per stamp per 24 hours . Quality of the rock

Formation

Fineness of the bullion

2-6S

Easy

Quartz

'980

Water required in Working Quartz.

Each stamp uses 10 lbs. per minute. Each pan uses 16 lbs. per minute. Each settler uses 9 lbs. per minute. If the water is run from the mill into settling tanks it can be saved with a loss of 20 per cent This will make the actual supply of water required in pounds per minute to be as follows : For one stamp, 2 ; one pan, 3*2 ; one settler, 1*8.

Power required for a 6o-Stamp Mill.

60 stamps, at horse-power . 22 pans, at 4 horse-power 1 1 settlers, at 3 horse-power

3 ooncentraton, at 2 horse-power .

I rock-breaker Friction

Total power required

67 '5 horse-

power.

If

235*0 horse-power.

358 METALLIFEROUS MINERALS AND MINING. Water r&quired for a 6o-Stamp Mill.

225 hone-power will require per minute . 169 lbs.

60 stamps ,, ,, . . 600 lbs.

22 pans „ „ . . 352 lbs.

II settlers .. „ . . 99 lbs.

Total water required

1220 lbs.

Of which 1*051 lbs. used for stamps, pans, and settlers can be re-pumped to the tank at a loss of 20 per cent, and the 169 lbs. for the engine can be condensed at a loss of 50 per cent This will leave the actual amount to be supplied as follows :

2oper cent of 1*051 lbs. 210*2 lbs. 58 per cent, of 169 lbs 84*5 lbs.

Total water per minute . . . 294*7 ls.

In No. 4 screens the holes are th.of an inch in diameter, and there are 144 holes to the square inch. In No. 6 screen the holes are th of an inch in diameter, and there are 324 to the inch.

At Black Hill, on the River Yarra-Yarra, in Victoria, sixty stamps, weighing 700 lbs. each, crush 96 tons of clean hard quartz a day, or a little over tons each. The stamps make about 70 blows a minute and revolve. They are worked by a 100 horse-power double-cylinder engine, 18 inch, which, besides working the stamps, works two 13- inch plunger pumps, with other work besides. The cost of crushing ore is 4J. per ton.

The work of an ordinary stamp may therefore be taken at a maximum of tons of ore crushed in twelve hours.

The attention of Cornish engineers has lately been directed to means whereby this result may be largely increased, by securing a greater number of blows of greater power per minute.

Among the inventions for tliis purpose are the stamps of Patterson, Sholl, and Husband. Patterson's Elephant Ore Stamp is provided with a spring, the action of which is to draw the stamp head back the moment the blow is struck, so that the rock is shattered into grains without being ground into powder. A machine with two heads is at work at Wheal Uny, Cornwall.

Modern Stamping Machines. 359

It is driven by an 8-inch cylinder engine, with la-inch soke and from 10 to 11 horse*power. Each head makes nearly

a Saou.'i PmuHATic S

130 Strokes a minute, and the ore is passed through a very line grating at the rate of 1 ton every 75 minutes, or about 9 tons

36o METALLIFEROUS MINERALS AND MINING.

in I a hours. The cost on ore to the extent of 1,800 tons a month is estimated at 9. per ton.

Fio, ijl-FiOKT Vuw or Shdu.'* Phiuiutic Srutr.

Illustrations of ShoU's Pneumatic Stamp are given in figs. 137 and 138, and may be thus described;

husband's stamping machines. 361

The stamps are either fixed on a suitable foundation, or are self-contained. The direct-acting stamps are driven by steam direct, and compress the air on two sides of a piston in the pneumatic cylinder and stamping stem. It is from this arrangement the cushioning principle is obtained to counteract the violence of the descending blow of the hammers or stampers.

As the piston descends into the air cylinder it compresses the air, and thus provides an elastic agency competent to regulate the blow of the hammer to the required stroke, and thus in effect converting it into a self-regulating action capable of overcoming any danger which may arise from a negligent supply to the hopper. The maximum number of blows per minute are 150, and it is claimed for this stamp that, owing to the peculiar character of its principle, much smaller stamps can be used either for prospecting purposes, or where portability becomes a necessity through bad roads, &c.

One of these stamps is in use at the Botallack Mine, Cornwall, where the tin ore has to be powdered very fine. It passes one ton per hour through No. 36 wire gauge grates, making 145 to 150 blows a minute.

Husband's stamps are somewhat similar, emplo3ring an air cushion or break in the same way. One in use at Smeddle's gold mine, in Nicaragua, has a head weighing, with everything attached, 830 lbs. It reduces 12 tons of quartz ore so that it will pass through fine gratings every 10 hours.

In stamps having a head with a large surface there is a difficulty in getting the powdered ore away from the centre. To obviate this difficulty Messrs. Harris & Rounsivello have contrived a large head, with a round hole through the middle of it, down which the water and ore are supplied; and Mr. S. H. F. Cox has invented a machine to use this head which weighs one ton, and by the aid of two large cams, worked by steam, he proposes that it shall give 200 blows a minute. As far as experience goes, however, a head of moderate weight working quickly is better than a very heavy head which reduces the tin ore to slime, and which in the case of

362 Metalliferous Minerals And Mining,

gold would make the particles so small that they would flow ofif in the waste water. On the other hand if gold quartz ore is not crushed fine enough the grains of gold are lost, embedded in the waste quartz. Each mine, almost, requires its own adaptation of stamping pwer and machinery.

Chapter Xxxviii.

ON THE DRESSING OF METALLIC ORESConiimud.

Jiggii%— The Different Specific Gravity of Different Mineral Substances, a reason why they can be mechanically separated — Table of Rates at which various substances &11 through Water— Introduction of Hand Jigging — Mechanical Jigging — Principle of Jigging— Jigs with Movable Sieves — Jigs with Fixed Sieves — Self-acting Continuous Ore Dressing Machinery— Green's — Rotating Jig or Buddie — Buddies — Ordinary Round Buddies — Slime Pits — Tozing — Machinery for Retreatment of Ores — Dressing Tin, Copper, Silver, Gold — Methods pursued in Brazil and in Victoria.

Jigging. — It will have been observed that the various metallic and non-metallic substances noticed in these pages are of different specific gravities ; and it is this fact which is taken advantage of and utilised in cleansing and separating the metallic ores after they leave the stamps or grinding pans and mills. Being of different weights compared with an equal bulk of water each metallic ore takes a different portion of time in falling through a given space of water. The following German table of these velocities, given by Dr. Raymond,* will illustrate this difference :

Table showing ths Distance in Prussian Inches that Spheres OF various sizes of different substances will fall through Water in one Second of Time :

Diameter in

Gold

Galena

Blende

Quarts

linei

spec gray. 19*9

spec gray. 7*5

spec grav. 4

spec grav. 9*6

29*814

4

21*082

3S73I

17*728

20*412

25*266

Mining Statistics of the WeU

364 Metalliferous Minerals And Mining.

Now, taking galena, as in the last chapter, to start \-ith, we see that it is half as heavy again as blende, and as heavy again as quartz, its two chief associates. The earhest attempts to utilise this different in weight was by hand jigging, which, by means of a sieve in which the combined ores were shaken up and down in water until the lead took the lowest, the blende the middle, and the sand and clay the uppermost place, seems to have been first practised in Bohemia in 15 19. After this the sieve was attached to a frame, and the shaking done by boys or girls by means of a lever handle, both plans being still in operatioa Between 1840 and 1850 the plan was adopted of attaching four or five of the movable sieves to a shaft

Fig. x39.<-JiGGBit, WITH Okb im Plungbk.

Fig. X40.— Jicgbk, WITH Osx IN Fixed Though.

turned by a water wheel, in the manner shown in fig. 139, A being an eccentric turning on a shaft, b the sieve containing the ore, c a box or hutch containing water. At every revolution of the shaft, therefore, the sieve b would be shaken up and down in the water, which, passing through the sieve, would.gradually sort the materials, the lead occupying the lowest place as before described.

More recently the fixed or stationary sieve, as shown in fig. 140, was adopted, a, the eccentric on shaft, b the sieve con* taining ore in box or hutch c, and d, the plunger, which is worked up and down at every turn of the shaft, and in so doing forces the water in the box c up through the ore, by which

Continuous Jigging. 36$

means the ore is washed and arranged in the manner already described This fixed sieve seems to have been first introduced into Hungary in the year 1828, and into Cornwall by Captain Petherwick in 1832. These two processes form the base or principle on which all subsequent elaborate jigging machines and processes are founded.

It should be explained that a layer of clean ore of a larger size than the mesh of the sieve is placed at the bottom of the sieve, and through this, in the process of jigging, all the ore of a smaller sLse than the mesh of the sieve finds its way into the hutch below, firom whence it is taken at the doors or valves e e. When the sieves and hutches are placed in a row, each one is finer than the last, until at last only veiy fine tailings or wash flows off to the next process.

The next step in advance was to make all the operations fi'om the crusher or stamps self-acting, so as to save time and cost of laboinr, A process by which this might be accomplished seems to have been invented simultaneously by two Germans, Vogel of Joachimsthal, and Wimmes of Clausthal, in the year 1850. This object has now been accomplished to great perfection. A variety of very ingenious and complicated processes are adopted at the mines of the Hartz and Erzgebiige, and perhaps one of the best examples of this continuous process may be seen at the Van Mines in Montgomeryshire.

In this country Mr. Geoige Green, of Abexystwith, has paid great attention to the whole question of the dressing of ores, and figs. 141, 142, and 143 represent his patent Self-Acting Dressing Machinery, and they will serve as an illustrative example of this class of ore-dressing machinery.

In fig. 141, A is the crushing mill, with rollers 26 inches in diameter, into which the ore stuff to be treated is put. When these rollers are started, the whole of the machinery is set in motion, and the work goes on regularly without hand-dressing. B is a revolving classifier which receives the crushed stufif firom the rollers. The perforations in this classifier have their size

For dabonte descriptions and Ulustrations see MifUng and Enghuer-' ing Journal of New York 1878,

366 Metalliferous Minerals And Mining.

aded to the kind of ore to be treated — the richer it is in minea the larger the holes, , uid the poorer it is in mineral die smaller the holes. Ijimps not suffidently broken are carried back to the crusher by the elevators A, while all that passes through the holes is delivered into an iron trough B, which conveys it on to the next operation, which is performed by c, D, K, — which are three of Green's Patent Automatic Classifiers and Feeders. Each of these dassifieis is covered with perforated iron plate of a suitably-zed perforation to suit the first dassiher, B, each descending one being I finer than the one I ' above, so that b, the

i I first, is the coarsest,

I and E, the fourth, is I j the finest Perforated

I ; pipes are placed inade

: each classinf; tiom- I mel, from which a suf-

I I ficientquantityofwater

plays on the ore stuif

Pic. [q thrOUgh the

Green'S Jiggers. 367

perforated plates all the slimes and panicles which are finer than the holes — thus all that passes through the perforated plate of one classifying trommel is dischaijed into the next in succession, whilst a sized product is discharged at the end of each into iron troughs or shoots, c, d, e, which convey it into a jigging machine - to suit In succession, then, each classifying trommel discharges a sized product entirely free from sHme, and out of the trough surrounding the last, all the slime and finer particles are dischai into a launder, which carries them to be treated

apart firom the rougher ores in f, g, h, i, k, which are five patent saddle- clasfiers and feeder, and which are made with inclined sides meeting in an inverted pyramidal [>oint at the bottom. A anient of water with the slimes, &c, dehvered by the last riddle in suspension, flows into a classifier at one end, deposits some of its suspended matter, and flows off at the other end into a second classifier, and then onwards to the others. These classifiers are of graduated sizes, the first in order being the smallest, and the current flows through them at diflerent velocities—so that in the first and smallest, the current being the

368 Metalliferous Minerals And Mining.

Strongest, the largest particles are deposited, and smaller ones in the next, and so on. The smaller classifiers are provided with water pipes attached at the bottom to deliver a spray of clean water at a head of 15 or lo feet pressure, and sufficient in volume to cairy forward the dead slimes to the last and laiest classifier, where the current is very slow and weak, and which has no pipes connected for clean water— the current being almost stagnant in this; all pre worth saving is sure lo depodt itself The classified stuff from F, c, H, is delivered by the troughs/ g, A, into ' the jiggers f, g, h, and the stuff from I and K through troughs i, k, into either buddies or trunks.

Fig. i43.-Eliwatioh of Jitwn-> C, D, E, G, H, OTC six Of DaVtes'S

Patent Three Compartment Jiggers, which receive the classified stuff delivered by the classifiers as explained above. The jigger comprises a hoiixontal hutch, constructed of wood 01 iron, which is divided into two three, four, or more compartments, by transverse ends and partitions. A vertical partition extends along the upper part of the compartments ; and on one side thereof there are a set of plunges or pistons to produce the jigging motion of the water, whilst a scries of sieves are placed on the other side. On the top of the partitions there are fixed a numb of standards to carry a longitudinal shaft on which the eccentrics arc fixed, and which being connected by rods to the plunge put the water in motion. The separation is effected by the jigging action of the water with which the hutch is filled, and which is made to work up and down through the sieves by the plungers. A layer of ore is put on the sieves, which has the effect of allowing particles of the same specific gravity as itself

Buddles And Buddling. 369

to pass through, whilst it keeps back any particles of less specific gravity, which last are gradually washed over the end from each compartment to the next lower one — the light waste from the last compartment finally passing away. A suitable appliance for regulating the stroke of each plunger is attached. Buddies, or other efficient slime machines, are attached to the larger classifiers, and the stuff flowing in a perfectly even current from the bottom of such classifiers on to each separate buddle, makes them quite self-acting, and of course more effective. All the labour required is to raise the deposited ore out of the jigger receiving box, and off the beds or buddies, to make room for other deposits. The finest or dead slimes are worked by an ordinary paddle trunk. The whole is complete and continuous, and worked without labour from the roughest prills to the finest slimes — each distinct size having a machine suited in speed and action for its treatment A good many of these machines are now working successfully in this and foreign countries. At some mines, in addition to the „ „

jiggers, a rotatmg buddle or orJiggkk.

jigger, of which a section is given in fig. 144, is used for separating the larger ore. The ore is supplied with a plentiful stream of water at a ; it tries to fall down the concave slope B, but is thrown back repeatedly by plates placed diagonally on a revolving light framework cylinder c The light earthy matter escapes into the trough d, and is taken away for further treatment. The larger ore, cleaned as it travels, is carried along the buddle for about 8 or 10 feet, and is thrown out in a clean state at the other end.

Buddies and huddling, — The slime that flows away from the processes just described has to be further treated by huddling. An ordinary buddle is a circular hole or framework let in the ground, as shown in fig. 145.

A A represents the slime and water flowing from the jiggers.

B B

370 Metalliferous Minerals And Minikc.

This flows over the central boss b, and runs down the sloping floor c c In doing this the particles of lead being heaviest are deposited first, about i i. The blende is next deposited, about . 2 1, and the earthy matter lowest, about 33. d is a piece of cloth attached to a frame B, which turns around the central pipe or stem, and smooths the surface and helps to distribute the materials over the whole floor.

There are long buddies with gently sloping floors, and many adaptations of the principle here illustrated Usually the waste flows from the buddies to the slime pits, where any particles of lead there may remain sink lowest, and are ultimately recovered ; and, passing through a number of such pits, all the mineral matter in the water sees down at last, and the

Fio. 14; — Oksihakv Cikdlak Buddli.

water, but for the colouring matter it has received, flows off comparatively pure.

Latterly, contrivances similar to those just described, but more delicate in their operation, have been adopted for the further treatment of the slime and waste. A series of these has lately been erected at the Van Mines, at a cost of about 6,000/., and profit of some 6,000/. to 7,000/. a year is made by treating over again the waste heaps at the mines. At some mines the fine slime flows into tubs, which when full are beaten with blows all around, like the ' tozbg ' of tin, which process helps the line particles of lead to sink to the bottom, whence they

'J

a

'it

372 Metalliferous Minerals And Mining.

are recovered. Lead ore is usually dressed to a quality of 75 to 76 of metallic lead.

For most copper ores the process of treatment is similar to that described, but the average final proportion of metallic copper in the ores of this coimtiy is, as we have seen, from 6 to 7 per cent.

The process of jigging is dispensed with for the most part in the treatment of tin ore, for, being powdered very fine, it flows at once to conical buddies like those just described. It is further treated sometimes in a concave buddle, known as Borlases, where the heavy tin ore accumulates in the centre. It is also treated in sloping pits and in tubs by tozing, as already described, frequently by roasting in addition, to drive oflf sulphur, until, as black tin, it is fit for the smelter. In 1877, 14,142 tonsf dressed ore produced 9,500 tons of metallic dn, and a similar proportion has prevailed since the year 1872, so that we may regard 100 lbs. of tin ore as equivalent to 70 lbs. of block tin.

Silver is, for the most part, as we have seen, a chemicallyassociated metal, and it is not often that the whole proportion of silver in its ores can be extracted without passing them through the smelting house. Fig. 146, adapted from Dr. Raymond's book, is the representation of an ordinary silver-dressing mill in Western North America.

The last reference shows that mercury is used to some extent to separate the silver.

Gold, — As finely-pulverised ore containing gold flows through the fine gratings from the stamps, many processes are used in order to intercept the precious metal, the principle of which may be summarised in the order followed, thus : — I. Gently sloping troughs, across which are nailed thin boards or riffles, which intercept the heavier particles of gold. 2. Hides with the rough hair upwards, which still further arrest the grains of gold, as the grass formerly did before mining began. 3. Rough blankets, spun on purpose, of a hairy kind, which intercept the finest grains. The natives of Aruba Island, one of the Leeward Islands in the Caribbean Sea, pour the water con-

Process At St. John Del Rey Mine. 3/3

taining the gold upon the woolly head of one or more of their number, which is a very effectual means of arresting the gold. The two last of the foregoing processes are assisted by the use of mercury, between which and gold there is a great affinity* This is spread on the hides and blankets, or upon copper plates laid in the troughs, or poured in with water flowing from the stamps, when the grains and particles of gold and it coalesce and form an amalgam, from which the mercury is afterwards separated, to be used over again. The details of the ordinary process followed at St. John del Rey Mines in Brazil may be briefly stated thus. The pulverised ore and water running from the grates near the stamps is further diluted with clean water, and is conducted over slightly inclined tables or ' strakes,' which are from 27 to 35 feet long and an average of i foot 6 inches wide, with a fall of one inch in a foot Bullocks' hides, tanned with the hair on, are spread over the first sixteen feet of the strakes, and baize cloths are placed below, followed below by another series of overlapping skins. These skins and lengths of baize are washed at regular intervals in separate tanks, and the product amounts to 0*42 of a cubic foot per ton. This sand goes to the amalgamating house. The sand from the middle strakes contains some 6 ounces of gold per ton, and is further enriched by being washed over another system of strakes. The products of the lowest skins are called ' tail sand,' and they are treated over again.

At Mount Egerton, in Victoria, the powdered ore is washed into lockers, where it is received on trays placed one over the other, and which have perforated sides, and contain quicksilver in the bottom. The loose gold is quickly acted upon by the mercury, and an amalgam is formed ; the water carrying away the sand which flows over inclined planes or strakes' covered with blankets containing quicksilver. On these part of the remaining gold is caught But out of the tailings the Chinese, by repeated washings, contrive to earn wages reaching often as high as xo/. a week. At St John del Rey, too, a good proportion of gold is lost, and the same is true at most gold mines.

?74 Metalliferous Minerals And Mining.

Still, if the Chinese, by painstaking, make money out of the

j tailings, the white men ought to do so also.

The details of the processes employed vary in different parts

of the world, but the principles on which they proceed are the

' same everywhere. We shall have to refer again to them in the

next chapter, which treats of hydraulic gold mining.

Chapter Xxxix.

Hydraulic Gold Mining.

The Pan— Cradle— Long Tom— Broad Tom— Artificial Sluice— Natural Sluice — Top improductive Drift — Mining — Hydraulic Excavation — Runs — Cleaning up, &c

This is the name now given to the various processes by which gold is sought for in the superficial alluvial drifts.

The Pan, — The earliest adventurers used simple pans or shallow dishes, in which the auriferous drift was waed by hand. Pans are still used by adventurers and prospectors in new gold fields. They are nicely turned wood bowls, or pans of copper or brass, about i6 inches diameter and nearly 2 inches deep in the middle. By careful manipulation the grains of gold collect in the deepest part of the pan, where they are of course secured.

754 Cradle. — Following the pan came the 'cradle,' which was a wooden box, about 3 feet 6 inches long and i foot 6 inches wide. It was placed in a sloping position, and fixed upon rockers. It had also a movable hopper and slides. The gravel was well shaken and washed in this, the contained gold being secured in the lower part of the cradle.

The Tom. — Following the 'cradle' came the 'torn,' which soon became divided into 4ong toms' and 'broad toms.' The ' long tom' was a wooden trough or box, from 12 to 14 feet long and 18 inches wide. It had a grating in the bottom, at the lowest end, when the tom was placed in a gently sloping position for use. Underneath this grating was placed another wooden trough, across the bottom of which were fixed thin pieces of wood or riffles. The whole apparatus was fixed in a

376 Metalliferous Minerals And Mining.

gently sloping position, near the face of the excavation, over the top of which a stream of water was conveyed to the upper end of the torn. Into the upper trough, with the stream of water running through it, the auriferous earth was shovelled, and if at all stiff it was stirred and worked by a man. The grate at the bottom intercepted the larger stones, which were removed. The smaller stuff containing the gold fell into the lower box, along which the lighter earth was carried off by the water, the gold, from its greater gravity, being intercepted by and resting against the cross bars or riffles.

The broad tom,' or Victoria Jenny Lind,' was the same in principle, but was made only about half the length of the long torn.' It was also made only 12 inches wide at the upper end, but it opened out to a width of 3 feet at the lower end.

The Sluice. — Gradually, and almost universally, the *tom' was superseded by the sluice, which is of two kinds, the natural and the artificial. The natural sluice is a long channel cut in the floor of the excavation, having a slope or inclination wherever possible, of only one in forty or fifly. The bottom of this channel, even if it be on the bed rock of the coimtry, is not of itself hard enough to stand the abrasion of the water and of the drifted matter running over it It is therefore covered with boards or rough planks, or it is paved with hard stones with the grain placed vertically. These are not less than 20 lbs. weight, but they are often swept away by the force of the water. Where the wash-earth is soft and loose either of the two first basements will do ; but where it is tough and hard the pavement of stone has to be adopted.

The Artificial Sluice consists of a series of troughs about 12 feet long, like the upper trough of the Mong tom.' These are made of rough boards, the lower end being made smaller to fit into the end of the next trough, and at the lower end of each trough a bar or grating is usually placed to intercept the coarser stones which are thrown out The troughs are also often provided with a loose bottom, perforated with holes, through which the gold and small dust sink into the bottom of the trough.

Treatment Of Auriferous Drifts. 377

These troughs are fixed on trestles at a slope of one in forty or fifty, the slope depending upon the quantity of water avail able. If this is small the slope must be greater, but if the supply of water is plentiful the sluice is placed as slightly sloping as possible.

In sluices of both kinds the auriferous dirt is placed at the upper end of the sluice, and the particles of gold sink in the interstices of the pavement or other bottom of the natural sluice, and on the lower bottom, or against cross riffles in the artificial sluice. The gold is most effectually saved where the sluice is long and the inclination very gentle. The ground sluice requires six times more water than the artificial sluice, but it wants less manual labour. The adoption of either plan at a mine depends, therefore, upon the relative cost of water and men in the particular district

In the case of the ' long tom ' and the artificial sluice the wash-dirt' has to be lifted into the upper end by manual effort ; but where ground sluices are available the aid of water is employed in the process.

The auriferous drift is, as we have seen, covered with a greater or less depth of other unproductive drift, which has to be got rid of. In Australia, when this covering is only lo feet thick and under, it is removed, and thrown on one side. If it is between lo and 30 feet in thickness, and it is of a hard and compact nature, the underlying auriferous drift is mined, and the top left standing. When the top drift is over 30 feet thick, whatever its nature the underlying gold drift is generally mined.

Supposing the gold drift to be worked in an open excavation it is worked much the same as a railway cutting is carried forward. Then if a good supply of water is available, a stream is turned on to the earth thus obtained, which is thus washed into the ground sluices prepared for it If the process of extraction be mining, the earth is similarly placed under the influence of a stream of water ; and this remark will apply to those older and deeper auriferous drifts which, as we have seen, figs, 30, 3 1, and 32, lie under tertiary basaltic deposits.

3/8 Metalliferous Minerals And Mining.

In both cases the rougher stones are thrown out along the course of the sluice.

In Australia, where the bed rock under the auriferous drift is granite, tin ore is often found in its didntegiated upper portion, and hence sometimes alluvial tin mining becomes the

most profitable of the two. The fonns of the grains of gold are found to differ according to the nature of the underlying rock. If it is slate the grains are cubical, if granite they are

flat plates and scales.

Modern Hydraulic Gold Mining. 379

Hydraulic Excavation. — More recently, and especially in California, water has been employed, instead of men with picks and spades, to tear down the face of the excavation before it is used to convey the drift along the sluices. We thus reach the opposite of the early condition of alluvial mining. At

first the drift was carried in small quantities to the water, now the water is brought iii large quantities to the drift.

Figs. 147 and 148 illustrate these two opposite conditions. Fig. 147 is an adaptation from the old work of Maw, on his

38o METALLIFEROUS MINERALS AND MINING.

'Travels in Brazil,' showing the primitive way of washing for gold and diamonds by the slaves, and one certainly cannot envy the position of the overseers. Fig. 148 illustrates the ordinary method of modem hydraulic gold mining. In the latter case the water is often brought from a great distance, and at a considerable expense, in pipes or flumes,' as seen in the right hand comer of the figure. It is thrown against the face of the excavation from a nozzle, which is of various kinds, and which is attached to the flume by a flexible hose. The force of the water is very great, and the gravel, sand, or mud bank is by this means easily undermined and washed away.

This method of mining is most advantageous where the face of the drift is from 30 to 60 feet in depth. It is safe also for the men, who are in no danger, as in the work of ordinary excavating, of being buried under the falling debris.

In this case the overlying unproductive drift is not first removed, nor has mining to be resorted to, but the whole of the drift is brought down and passed through the sluice.

Hydraulic mining of this kind is not so applicable to Australia, because of the usual flatness of the ground, and the consequent difficulty of finding fall for the water. Australian gold, too, is more flaky and light than Califomian, so that greater care and skill are required in intercepting it, lest it should float off with the water.

The wooden sluice in Califomia is made of half-inch boards rough from the saw. It is 16 or 18 inches wide, and it never exceeds 5 feet Its fall or grade ' is from 8 to 18 inches in 12 feet The stream of water is usually about 2 inches deep over the bottom There is also a false bottom, as in the long tom,' which is perforated with holes, and under this is the true bottom, on which are wedged riffles, which are placed sometimes longitudinally, with the pieces across, so that the bottom is divided into panels or compartments, and sometimes diagonally across the trough. An average number of twelve men are employed to throw the wash dirt into the sluice, and each man will throw in from 2 lo 5 cubic yards a day.

Run. — The riffle ban soon wear out, and the time they last

Cleaning Up. Tail Sluices. 38 1

often determines the length of the run, or period during which the gold is allowed to accumulate in the sluice, otherwise the run generally lasts from six to ten days.

Cleaning up. — At the end of these periods comes the cleaning up. At these times, which last from half a day to a day, the men cease throwing wash-dirt into the sluice. They take up the riffle bars for a length of about 30 feet The water flows on and washes the gold to the top of the remaining riffle bars, where, any dirt remaining having been washed lower down, the gold is scooped up with a spoon into a pan where it is finally washed and separated. Another length of riflEles is then taken up, and the process is repeated until the whole sluice is cleared.

The extraction of the gold from ground sluices that are paved with stone is a more difflcult process, and the gold dirt collected in it has afterwards to be treated in a broad sluice or tom.'

The extraction of the finer particles of gold is assisted by the use of mercury. This metal is allowed to drop into the uppermost end of the sluice, and it usually amalgamates with the gold before these to metals have gone far down the sluice, both of them stopping at the first resting-place.

Sluice troughs are sometimes made double, so that there need be no stoppage while the process of clearing up is going on. The arrangement also permits two companies, when they can agree to do so, working side by side.

Tail sluices. — There are also tail sluices, which are often placed in the bed of a stream, where the ' tailings' from the first sluice are treated over again. Occasionally the water flowing along the floor of a tunnel in a mine is used for the purposes of a sluice. Some comparisons of the costs and results of the various methods of extracting driftal gold just described are given in the next chapter.

Chapter Xk

Sundry Particulars Of Work And Costs.

Gold — Quartz Mining — Alluvial and Hydraulic Mining -Tables of Particulars.— Silver — Altai Mountains —Dry Ore Concentration— Mode of Treatment in Mexico — Copper Cape Mines — Algerian Mines — Parys Mountain Mines — Lake Superior Copper Mines. — Tin — Costs of Work in Cornwall — Percentage of Black Tin to Ore ; of Black to Metallic Tin — Cost of Dressing — Cost of Prepared Ore per Ton — Banca, Australia, Red River, Cornwall, Stream Tin Workings. — Lead — Various Costs — Zinc— Various Costs. — Iron — Various Costs — Deepest Mine Shafts in the Worid.

The following particulars of work and costs derived from various sources will, I hope, be permanently useful for reference, and they will be of interest as showing prices paid and work done up to the present time.

Gold. — Quartz mining, — In Victoria recently seven mines produced a total of 25,783 tons of quartz, which was obtained from depths of between 400 and 500 feet. This quantity gave an average of 6 . 7 grains of gold per ton, or of the value of about i/. $s, per ton of quartz. The lowest amount was 4 ., and the highest 12 . 6 grains.

29,324 tons of quartz taken from five mines, at depths of from 500 to 600 feet, gave an average of 8 ., or one-third of an ounce per ton.

179377 tons of quartz raised from three mines, at depths of from 600 to 700 feet, gave 1 1 . 6 grains per ton, or of the value of about 2/. 2 j. to the ton of quartz.

The foregoing figures do not favour the theory that quartz lodes become less productive of gold in depth, as indeed, if they continue in the same strata, they should not

Cost Of Quartz Mining In Australia. 383

There are also rich discoveries at great depths; thus at Mariner's Reef, 83 tons of quartz gave 5 oz. 3 . of gold per ton.

Again, 32 mines in Victoria, with depths ranging from 180 to 650 feet, yielded on an average 1 1 . 4 grains of gold per ton, the lowest being i dwt 18 grains, and the highest 4 oz. It is considered that a yield of from 2 to 3 . of gold per ton of quartz will pay for crushing.

The lodes or dykes in the above cases varied in width from 4 inches to 120 feet, the mean width being about 8 feet, each lode varying in width in its course downwards and horizontally. The cost of pumping averages 3/. a day. The cost of raising I ton of quartz from a depth of 550 feet was 9J. per ton. The cost of sinking shafts was 10/. per foot.

At Black Hill, on the River Yarra- Yarra, the cost of getting quartz per ton is, in an open quarry 4. 2</., in undeipround mining gs. The cost of crushing was 4. per ton. The average yearly earnings of gold miners have increased from 93/. 16s, 2d, in 1873, to no/, in 1876. At the Little Annie Mine in Colorado, which is interesting as being one of the two highest mines in the world, 382 tons of rock were crushed in the close of the year 1877, at the rate of tons every 24 hours. The value of the gold obtained was ;$!4,58o, and the cost of mining and crushing /i,945, the yield of gold per ton being ;$[i,i99. In the beginning of 1875, tons were crushed, which gave ;Jio,507 ; the cost was JJI8,763. i8c., or a net profit of about 7 J. per ton of ore. The Americans can, generally speaking, quite equal the Australians in making a small proportion of gold pay a profit.

Alluvial and hydraulic mining, — In Australia foiu: men filling a long tom, or raised sluice, will remove and wash 24 cubic yards of ground per day — 6 cubic yards per man. In ground sluicing with a sufficiency of water the results will be more, varying with the skill of the men, the inclination of the sluice, and the density of the ground. A favourable instance is given of operations in the hill overlooking Allan's Flat, Yackandanah. The ground sluiced was a quartzosed gravel

384 Metalliferous Minerals And Mining.

3 feet deep, the quantity of water used was about 500 gallons a minute, the number of men 3, and the ground removed 150 cubic yards a day 50 yards a man.

In hydraulic ox jet mining the results vary according to the quantity of water employed and the height of its source, or its immediate fall above the point of operation, together with the compactness or looseness of the ground. The quantity of earth removed varies from 50 to 200 cubic yards a man. The costs of working a face of drift per day are thus estimated :

Three men, at Zs. each . . .140

360,000 gallons of water, at 0*33. . 10 o

Repairs and renewals 60

In airerage claims f of a grain of gold per cubic yard will cover costs. In favourable hydraulic mining the costs have been defrayed by a less proportion per cubic yard. The two following tables, given by Mr. A. J. Bowie,* will afford very full particulars of work, costs, and results at two of the claims of the La Grange Hydraulic Mining Co. in California.

Silver. — In the Altai Mountains, in the south-east of Siberia, the silver ore is quarried in open excavations, as well as in underground chambers, and after being picked and sorted the silver is obtained by smelting.

The following account by Herr Richter of the processes employed in the reduction of silver in Mexico gives many details of work, and it will supplement the brief reference to the dressing of silver ores given in chapter xxxviii.

The ores raised at the Tajo Mine at Rosario, near Mazatlan, are essentially mixtures of quartz with argentic sulphides, and probably some silver and gold, together with some galena, brown blende, and pyritic minerals ; the average contents of silver being 40 ounces and of gold 2 J ounces per ton, with from 6 to 8 per cent of lead and zinc The reduction is effected by

' Engineering and Mining Jaurtuilf December 15, 1877. Zeitsckrift fur Berg- ffiitten- und Salinenwesen, vol. xxiv. p. 264, as translated in the Proceedings of the Institution of Civil Engineers,

E]

M

K U

A

s

H

fid

Si

m

M

M

Cq M

o

Os

M a O

O o

H

00

1

i

r

z

a.

Treatment Of Silver Ores. 385

\he American method of pan amalgamation wiAoat previous roasting. The ore is partially divided, by hand-picking, into rich and poor classes, without, however, attempting to remove any of the lead or zinc minerals, which are passed by a mill of twenty stamper-heads, with rotating lifters weighing 7 cwt and making sixty 9-inch strokes per minute, through grates having apertures inch in diameter, 24 tons being stamped daily. The slimes pass first into a pit 3*3 feet deep and 9*8 feet in cross section, where the richer material forming the normal ore for the pans is deposited, after which a second collection of poorer stuff is made in a second pit of the same size, and finally the waste, together with that firom the pans, is passed through a series of catch-pits 9*8 feet long, 5 feet broad, and 3*3 feet deep.

The reduction of the richer slimes is effected in pan amalgamators of the improved Vamey pattern,' which perform the three operations of grinding the particles of ore to impalpable mud, mixing the particles with the chloridising agent, and reducing and amalgamating the silver minerals. The pan is essentially a mill, with cast-iron instead of stone grinding surfaces, which is adopted partly firom economy and partly fi-om the property possessed by iron of reducing the mercurial chlorides. These sur&ces are put together in segments, so as to be easily renewable, as they are worn out in forty days when worked at seventy revolutions per minute. The charge of the pans is 800 pounds of ore stuff firom the stamps, which is mixed into a thin mud by adding water and running the pan for half an hour or an hour until the materials are sufficiently ground. During this period a jet of steam is introduced, in order to warm up the contents to 176 F. Chloridising and reducing agents are then added in the following, proportions : sulphate of copper, 4 pounds ; salt, 40 pounds ; and mercury, from 70 to 90 pounds, including pound of zinc amalgam ; or about 13 times as much salt, and 32 times as much mercury, as is used in the Mexican or ' patio ' process of amalgamation.

Vide EUments of Metallurgy, by J. A. Phillips, p. 650 et seq. Also Hague and Kiog's Mina of Nevada aad Raymond's Reports &c.

3S5 Metalliferous Minerals And Mining.

The copper salt is added in somewhat laiger quantity than would be required for the chlorination of the whole of the silver, assuming it to be effected by cupric chloride. The reactions are considered by the author to be substantially the same as those in the patio ' process, and as probably occurring in the following order : amalgamation of metallic silver and gold ; conversion of cupric sulphate into chloride; conversion of silver sulphide by cupric chloride, with the formation of cupreous chloride, into silver chloride ; reduction and amalgamation of the latter by metallic mercury ; and, finally, decomposition of the mercurial chlorides formed by iron of the pan. The zinc amalgam is said to help by the production of electric currents. Like the Mexican process, the method is not well suited for the treatment of minerals containing lead, zinc, or antimony, the working of such ores being attended with a considerable loss of silver and mercury.

The amalgamation process proper requires about four hours, the progress of the operation being controlled by washing out samples of the mud at intervals, and observing the colour and foim of the mercury globule obtained, which should be grey, and ' tail,' or assume an oval form.

The finished charge fcom the pan is received in a cylindrical washing vat, or settler, and allowed to rest for an hour, whereby the bulk of the mercury and amalgam separate firom the mud and fall to the bottom. Afterwards the lighter particles are removed through a hole in the side by a stream of water, which flows for fifty minutes ; lastly, the bulk of the mercury is separated from the remaining heavy mud charged with ore, hy drawing it from a lower opening for ten minutes. As the amalgam is very poor, owing to the large quantity of mercury used, only the excess of the latter introduced at each washing above a laige fixed amount is removed in clearing the settler, the whole quantity being only removed at intervals of eight days.

The waste or tailings of the first operation, consisting laigely of heavy metallic sulphides, with probably some silver sulphide, and containing about 35 per cent, of the original amount of silver

Results Of Dressing Silver Ores. 387

are reworked in four large pans or 'tailing mills/ which take charges of double the weight of those worked in the ore-pans, but are otherwise similarly arranged. An assay of this material gave 28 ounces of silver per ton, and appeared by vanning to consist of of quartz and of heavy sulphides, pyrites, blende, and galena. The reagents used per 1,600-pound charge are : salt 40 pounds, sulphate of copper pounds, and mercury 120 pounds, the latter being about seventy times the weight of the silver in the ore.

The working of the tailings, both in the pans and settlers, is exactly similar to that in the ore mills. The waste from the last washing, containing about i ounce to the ton, is passed through a catch-pit before being allowed to run to waste. A further quantity of so per cent of silver is recovered by the second operation, showing the final loss to be about 15 per cent, of that contained in the ore. Allowing four hours for the filling of the tailing tanks, the extraction of the silver from the ore, counting from the first charging of the ore-pan, is effected in sixteen hours. The amalgam collected is treated at intervals by filtration through canvas, after which it is washed in quantities of a few hundredweights at a time in a pan with water to clear it from mechanical impurities, filtered a second time, and finally heated in retorts holding 1,200 pounds. The time required for distillation is from eight to fifteen hours, on account of the great variability in its composition. The sponge silver for the retorts is melted in blacklead crucibles holding 50 pounds and run into bars.

The great advantages of the pan process, as compared with other metallurgical operations, namely, speed and cheapness of work, together with large production from a small plant, are, in the author's opinion, obtained by a considerable waste of silver, which he calculates at 187 per cent of the total quantity, and as due to the effect of Uie lead and zinc ore. Nearly the whole of the gold is, however, saved The loss of mercury is 2 pounds per 2,000 pounds of ore treated, or 80 per cent of the weight of the silver. The staff required is very small

With twelve workmen of all descriptions about 17 tons of (e

cca

388 Metalliferous Minerals And Mining.

are treated per day. The machinery is driven by steam power, the cost of wood for two engines being about 8/. daily. The total cost of working, including wages, materials, wear of machinery, &c., is about 2/. per ton of ore treated, or about IS, 2d. of silver recovered

The next table, by Mr. A. Trippel,* of New York, affords a view of the results and costs of the dry concentration of silver ore at the Manhattan Silver Mill, Nevada :

Copper. — At the Cape copper mines the costs of extraction and dressing ready for sale during recent years have been as follows :

Costs indnsiTe of all charges, carnage to England

indoded, in 1874 10 9 per unit

„ ,. n 187s 10 2 „

,t .1 If If '876 9 10 M

Or an average of 9. 8. per unit on a yearly output of 12,000 tons of 30 per cent. ore. The cost of raising the ore to the surface is 2d. per unit, or 4/. 15. per ton of ore. In this case it is the high percentage of copper in the ore that enables the mines to be worked at a profit

Professor Ansted ' gives the cost of getting the ore at the mines of Boudendach in Algeria at 52. per ton, dressed to a percentage of 16. The dressing is put at 30X. a ton ; carriage to Port Tened, Ss. ; total, 4/. i&f., which, with freight to Swansea, 12., makes 5/. lor. a ton, to which should be added costs of management, &c. At 12s. per unit the value in Swansea would be 10/. per ton.

At the Parys Mountain Mines in Anglesea, the North Discovery and Carregydol lodes, fig. 55, averaged six to seven tons of copper ore, of about 5 per cent, value per cubic fathom. The groimd was hard, and blunted the tools rapidly. The cost of driving was from 9/. to 10/. per fieithom, and the cost of stoping 5/. to 6/. per cubic fathom. The average cost of getting

Engineering and Mining of New York.

Scenery Science and Art,

Results Of Work At Manhattan Silver Mines. 389

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Charcoal coosumed

m

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390 Metalliferous Minerals And Mining.

the ore out of the mine was from $s. 6d. to 7. per unit The dressing cost from 5. to 6s. per unit, to which, iif we add costs of management and renewals, the ore would cost from los. 6d. to I IX. per unit

At the Lake Superior Copper Mines the cost of raising ' stamp work ' — the middle quality of the ores — at the Hogan Mine, inclusive of all operations necessary for preparing the ore for market, after the mine had been laid open for stoping, was, some years since, as follows :

Sloping

FiUing, landing and wheeling .

Tramming to kilns

Bnrning, including wood and labour

Dressing

Steam engine and labour at stamps Miscellaneous charges, carpenter, smith, &c.

Per ton

02 Go

oo6i

/4 42

The stamp work is reckoned to produce 90 per cent of pure metal.

The production of metallic copper from the whole of the workings of the Hogan and Stourtenburgh Mines was approximately 225 lbs. per fathom.

Tin. — The following particulars of prices paid for general mining work in Cornwall are partly applicable to mining for copper.

The sizes of shafts in the county are from 5 to 15 feet long, by 3 to 5 feet wide. The prices paid for sinking shafts are :

£ £ In soft clay slate, to a depth of 20 fathoms from

surface 2 to 3 per fiuhom

„ „ below this depth 3 to 4

In hard day slate, to a depth of 20 fathoms . 4 to 6

„ „ below this depth 5 to 8

Where powder is used, or in ordinary blasting

ground, to a depth of 20 £sithoms . . 6 to 8

below this depth 10 to 30

In extreme cases of hardness

70 to 80

Proportion Of Metallic Tin To Black Tin. 391

Driving levels, about two-thirds of the preceding prices. Smaller levels in easy ground are driven at from 8x. to 12s, per fathom forward.

Stoping costs about two-fifths of the price of driving levels.

Average cost of breaking and selecting the ore, and sending it to the surface, 4. to Ss, per ton.

The eight mines named below gave, in 1866, the following proportions of black tin to the ton of ore raised :

lbs.

lbs.

Huel Kitty .

. . 84

East Cam Brea

Dolcoath .

Polbeiro Consols

Tin Croft

. . 35

Huel Coates .

Huel Uny

Ilanwil .

At St Ives Consols as much as 1,344 lbs. have been obtained to the ton of ore, but the average was only 45 lbs.

In 1856, of thirty-two of the best mines the highest average was given by Huelvor, which gave 144 lbs. to the ton of ore.

The present percentage of black tin derived from all the tin ore sent through the stamps and dressing floors of Cornwall is estimated at 2 per cent., or nearly 45 lbs. to the ton of ore.

In 1877, 14,142 tons of black tin gave 9,500 tons of metallic tin. It may be taken, therefore, that 100 lbs. of black tin yields about 70 lbs. of metallic or block tin.

The cost of mining and preparing tin ore for the market has decreased during recent years at the best mines from 52/. to 27/. per ton. Possibly 35/. may more nearly represent what at present may be considered the lowest average price as spread over a number of the best mines.

Fifty tons of ore will ordinarily have to be mmed to produce one ton of black tin. If we put the cost of stoping per fathom at 3/., and take four square fathoms of a lode 4 feet wide as equal to 50 tons, this would give 12/. The cost of dressing, from the pif s mouth to the ore bin, varies from 5/. to 12/., but 9/. is taken as the average; this would make 21/. Then come dues, cost of management, pumping, and renewals,

392 Metalliferous Minerals And Mining.

SO that we cannot at present reckon upon a much less cost than 35/. per ton.

At the stockwerk of Altenberg, Saxony, fig. 66, the whole mass is quarried, stamped, and washed; the proportion of black tin being 2 per cent of the whole.

At the alluvial tin mines of Banca, a workman, in a day of nine hours, removes, with the aid of water, from 350 to 530 cubic feet of earth. The top ground is dug off and removed, and then a stream of water turned on. Bowls, launders, and strips or strakes, are used for intercepting the tin, as in alluvial gold mining. The experienced labourers receive i/. per month and their board. The new-comers only receive 13J. 4/. and their board. The quantity of earth removed yearly for each person of all sorts at a mine is estimated at about 12,000 cubic feet ; the yearly yield of metallic tin for each employ of all kinds being 12 cwt

In Australia, in washing for stream tin, a man is said to handle, or pass through his hands, 10 tons of earth a day.

In Cornwall, in 1876, 800 persons of all sorts were employed in alluvial tin mining on the Red River. The production of tin ore amounted in value to 18,460/., and the average earnings to i ox. a week.

Lead. — At the Van Mines at the present time the cost of stoping ranges from 4ar. to 8ar. per fathom. In Cardiganshire and Carnarvonshire the prices range higher, as they also do in lodes in the limestone districts. The cost of driving is nearly double this price. The cost of sinking winzes about the same —of fxriVif, or working a winze or a shaft upwards, about onehalf more.

The paying lead mines contain from 25 cwt. to 3 tons of ore per fisithom, with varying quantities of blende. There is not as yet, I think, an instance of a lead mine paying on an average production of less than 25 cwt per fathom, but there out to be many. In an ordinary mine, in which from onehalf to two-thirds of the area of the lode contains ore, the cost of stoping may be roughly taken at about one-third of the total cost of the ore when prepared ready for sale : one-third being

Costs Of Mining And Dressing Zinc Ores. 393

apportioned to development and exploration, and the other third to pumping, general expenses, and management A rib of lead one indi wide in a lode represents lo to 12 cwt per &thom.

In Carnarvonshire the hand-dressing of lead costs from 1 81. 'to 20s. per ton ; but, by machine-dressing, it is done at an average cost of 13. per ton.

At the Flintshire Lead Mines, worked in lodes, the cost of dressing is put at about i6s. per ton.

At the North Hendre Lead Mine, which is worked in a ' flat ' lode or bed, fig. 97, the prices paid are : for raising lead, 20s. per ton ; for tramming the same a distance of 300 ards, 16s, per 20 tons ; for dressing the ore — most of it being in lumps — ready for sale, 9. per ton ; for driving levels in limestone j/. I Of. per yard.

Zinc. — This metal is, as we have seen, closely associated with lead ores. The cost of dressing the ore at the Flintshire mines is from ii. to i6x. per ton.

Mr. £. Gybbon Spilsburg ' gives the following table of the cost of zinc extraction at the Lancaster County Zinc Mines, Philadelphia :

Cost of mining 40 tons of ore a day at /i 00 . . $40 cx>

Transportation to dressing floors 2 00

Dressing 40 tons, loss in weight "26*63 tons dressed . . . 20 00

Two engineers at /i 50 3 00

Two tons of hard cool at 2 38 4 76

Labour in roasting 26*63 tons at /i coper ton . .2663

Fuel, 26*63 tons at /4 00 106 52

Labour to reduce, say 24 tons calcined ore, say 18 shifts, at /9 00

per shift 162 00

Fuel for reduction in furnaces, 25 tons at /2 38 . . 59 50

Fuel used for reduction in retorts, tons at /i 50 . 1 1 25

Retorts used, 54 at 75c 40 50

Condensers used, i8oat2c 3 60

f479 76 Ten per cent of above for wear and tear and general management. 47 98

Zinc produced would be at lowest possible estimate 9,900 lbs.

Eitgimering and Mining Journal New York, July 1877.

394 Metaluferous Minerals And Mining.

Dividing the above cost by this number of pounds would give under 3 cents as cost of zinc per pound. The following analysis shows the quality of the spelter produced :

Zinc 99*687

Cadmium -034

Lead *262

Copper Tnux

Iron "017

The following account of the zinc mines on the Schneeberg, Tyrol, will also be of interest :

These mines, amongst the most elevated in Europe, were formerly wrought for argentiferous lead ores, having in i486 employed 1,000 men. In 1866 they were reopened, and it was determined to utilise the large discoveries of zinc-blende which, together with some galena and a Uttle copper pyrites, form the bulk of the metallic contents of the lodes. These lodes are from 7 to 56 feet thick, and have been proved in direction for a distance of about mile, and by the outcrops in depth to more than 2,700 feet The chief point of interest is in the great differences of level that have to be overcome in the transport of the mineral from the mines to the dressing floors and smelting works across intervening mountain ridges. The St Martin, or principal working level, lies 7,763 feet above the sea level, and there are numerous workings above and below this point The Kaindl tunnel, by which a principal ridge is crossed, lies at an altitude of 8,262 feet The principal arrangement of the roads in this very broken system of transport are the following : — A lift 1,459 feet long, 623 feet vertical height, rising on the ridge above the Passeyer Valley, connects, by a railway rise, with one end of the Kaindl tunnel. This is 4,211 feet long, and crosses the ridge to the Lazacher Valley. From this

From James Forrest's Abttracts of Papers in Foreign Transactions and Periodicals for the Proceedings of the Institution of Civil Engineers.

Treatment Of Zinc Ores In The Tyrol. 395

point the road is all downhill, commencing with an inclined miles long, on a gradient of i in 11, leading to Meiem, where there is a second inclined plane 846 feet long, and 479 feet fall, at the bottom of which new and large dressing floors are in come of erection. From the new dressing floors a road of 5 miles, on a gradient of i in 135, leads to a third inclined plane, 1,430 and 479 feet fall, to a point on the road Sterzing, about miles distant from the railway station. From this it appears that &e stufi* from the mine travels first uphill about r,ioo feet for about mQe to the summit, thence about 3,240 feet down in 5 miles to the dressing floors. The farther distance to the station is nearly 10 miles.

A portion of the ore, that containing lead, is dressed at the mines ; the works, which from their altitude can only be used during four months of the year, include forty heads of stamps, eight V-channel classifiers (spitzluttm) two spitzkasten, eight percussion and nagging sieves, and ten double Rittinger percussion tables, the power being supplied by an overshot wheel driven by the water of the Schwarzensee, a lake 7,400 feet above the sea level The lower works at Meiem, which are available during nine months in the year, are divided into two parts : that for the coarser mineral, containing Blake crushers, picking tables, sizing drums, and coarse jiggers, is driven by a water-pressure engine, on Mayer's principle; the second, for the finer sizes, driven by a Girard turbine, contains 20 heads of stamps and ten double percussion tables, besides the necessary centrifugal pump elevators and slime pits ; a third portion, containing the crushing rolls, is not yet erected. In their present condition the mines are equal to an annual production of 2,500 to 3,000 tons of blende in lumps, and 4,200 to 4,500 tons in various dressed sizes, averaging 42 to 45 per cent, produce for zinc, and 320 tons of dressed lead ore, but when the machinery and road are completed these quantities will be increased threefold.

Iron. — The costs of working the Clay-Band ironstone of the Warwickshire coalfield in the years 1874-5 was :

39 Metalliferous Minerals And Mining.

s, d.

Getting and filling .

5 3 per ton

Hauling and laying

o 7 „

Overlooking and repairing

o 7 „

6 S

The ore was sold at iis. 6d. per ton delivered in trucks at the colliery.

The costs of working the mainland of the Cleveland ironstone is approximately lo. to ix. yl, per ton, apart from management and outside expenses.

It is said that Spanish haematites of 6o per cent strength can be delivered free in Philadelphia for 33X. per ton.

I conclude this chapter of statistics with a list of the deepest mines in the principal countries of the world, as compiled by Mr. W. Rowley, F.G.S., of Leeds,* which also includes the deepest shafts of coal mines :

Country

Name of mine

District

Mineral worked

Depth, yards

Austria

Adalbert

Birkenberg

Silver and Lead

Belgium

Viviers

GUly

Coal

Saxony

Zwickaw

Coal

Prussia

Samon

St. Andre

SUver

S44

Great Britain

Rosebridge

Wigan

Coal

Norway

Kongsberg

SUver

Hungary

Amalia

Schmeritz

Gold and Silver

Prussia

Camphausen

Saarbruck

Coal

Spain

La Luerti

Canada

Silver

Italy

Monte Masio

Gavarrono

T ignite

Sweden

Bersbo

Copper

Pays-bas (?)

Wbilhelm

Kerkiade

Cokl

Baden

Hagenback

Coal

Portugal

Taylor

Palhal

Copper

Is

Bavana

Max

Stockholm

Coal

Russia

Tuijinsk

Copper

To the above may be added the Snailbeach Lead Mine, Shropshirei which is now 463 yards deep.

1 Mining yimmal, October 28 1876.

Chapter Xll

General Considerations.

Large Proportion of Uninpofitable Mines — Unsuccessful British Mining in America — Causes — Want of Knowledge of First Principles — Insufficient Capital — Excess of Unproductive Capital — Exorbitant Prices paid for Mines — Expensive General Management — Ditto Local Management —Mine Gambling — Rules to Regulate the Sale and Purchase of Mines — Possible Reduction in the Cost of Working Mines— Remedies — Ponible Future of Successful Mining — Concluding Observations.

Admitting, as I think we must, now that we are approaching the end of our inquiries, the great scientific and mechanical interest attaching to metalliferous mines and mining, it is humiliating to have to confess that the majority of mining enterprises are commercial failures.

It is still more humiliating to be obliged to admit that this confession applies with particular force to mining in the British Isles, and the more so, since, for their size, these islands are the most highly mineralised portion of the earth's suiface. A larger proportion of mines pay, as far as can be ascertained, for working, in America and in Germany ; and the worst of it is, that, a rule, the most unsuccessful mines in North- Western America are those worked by English companies and under English management. It is said that of American mines introduced into this county within the last seven years, all but one or two have been Shires, and have entailed a loss of money amounting to 10,000,000/.

Then there are between 500 and 600 lead mines in this country, of whidi scarcely fif are paying a profit There are 104 copper mines, making returns of ore, of which, I do not think, more than a dozen are worked profitably. Indeed, we

398 Metalliferous Minerals And Mining.

may safely assume that the proportion of unprofitable to profitable mines is ten to one.

This is a serious state of things, and one that almost amounts to a national disgrace, and it behoves us to seriously consider whether it arises from unavoidable difficulties, inherent in mining, or whether any part of the cause of failure may be moved

Mining is, at the best, an adventurous business, and, as such, it is a business for energetic and adventurous men, bom explorers, who have time or money, or both, to spare. Happily, there are plenty such.

If my readers have followed this book closely, they must, I think, have come with me to the conclusion that mining need not be such a risky business as it is, and that the disproportionate number of unsuccessful mines may be considerably reduced. For, first, there are a good many such mines that, hitherto from want of knowledge, have been opened in strata where there can be little or no prospect of success. I know of many such — lead mines, for example — whose explorations are now being pushed forward in the soft black Lingula Flags below, and in the unproductive Bala beds above, the Llandeilo lead strata. One case occurs to me, where a ' lead mine ' has been struggling for years in the Wenlock Shale of North Wales, the discovery of an occasional string or bunch of galena enabling the explorers to defy the geologists.

Numbers of mines, too, in limestone districts are being unsuccessfully worked in shale, grit beds, and the unproductive dark limestone beds. Here, then, is a large class of mines which are imsuccessful on account of the ignorance of their promoters and managers of the first principles governing the accumulation of ore deposits.

The same ignorance has, I fear, often led to the loss of much money in unwise explorations in the known productive horizons of ore.

There are mines also that owe their abandonment to want of sufficient capital. The costs and possible requirements of the undertaking had not been carefiilly considered in the first

Classification Of Unsuccessful Mines. 399

distance. It is the old story, oft repeated, of beginning to build, and not bemg able to finish.' The result has been inadequate machinery to cope with the water, the expenditure of what money there was in an endeavour after immediate surface results, an inability to pay the rent, and the lapse of the lease ; and in some mines of real worth a sum of money being paid yearly for bank commission and interest that of itself would pay a moderate dividend on the capital actually necessary for the establishment of the mine. To mining readers more than one Cornish mine will afiford illustrations of this.

Another group of unsuccessful mines owe their failure to a mistake in an opposite direction to the last, which is the overloading of the mine with unnecessary and unproductive capital. Sums of from 10,000/. to 70,000/. are asked and paid for mines which a few moments of ordinary business thought will show could not at the best ever pay a mining profit on more than one-fourth of the sum, to say nothing of the additional capital required for working them. The misfortune is, that the very great success of one or two mines in a country, like the richness of one or two prizes in a lottery, throw a glamour and haze over the minds of the people who invest in such undertakings, and who, unfortunately, are usually people of limited means, who are eager to become rich, or to increase their scanty means.

The last-named group of unsuccessful mines is closely associated with another group, which is ruined by expensive management and working. If we imagine a company formed in London, with a lord for its chairman, and a general and a colonel among its directors, with a managing director, a secretary, and a consulting referee, in order to manage and carry on an ordinary grocery business in a small country town, we have supposed something that is not a whit more ridiculous than are the confederations firequently established to work good little mines which, at the most, cannot yield more than the profits of a grocery business. These mines, and there are numbers of diem, would pay a moderate profit to a limited local partnership, but the little profit is more dian swamped by the remuneration and travelling expenses of directors, secretary, engineers,

400 Metalliferous Minerals And Mining.

and the like. Happily, we find many such mines paying such local partnerships, especially where one of the owners resides or is often at the mine.

The baneful influence of the two last causes extends to the local management of the mines. The mine is worked and the reports are made too often, it is to be feared, with a view to the ' bull ' and ' bear ' operations on the stock market, and often with a view to the money to be made, or the greater share in the mine to be secured by a reconstruction or a refloating of the company, after a preliminary winding-up.

The fact, too, that more money is made in good times by floating such mines than by working them, induces a gambling and reckless spirit among all the officials, and, it may be, among the miners at a mine.

It will also be found that at mines which have been dearly paid for, and are expensively managed, the prices paid for driving, sinking, stoping, and for most work out of sight, average higher under equal conditions than do those paid at mines worked for business profit under careful personal management

Turning to foreign mines worked by Englishmen we see a few which, from their extraordinary riches, do pay. The remainder suffer from the causes already enumerated. They also suffer from others. Most British mines in America, for example, suffer from litigation. ' Jumpers,' as they are called, set up prior claims, and as in the newly settled countries they and their class form the courts, and sometimes supply the judges, the verdict usually goes against the stranger.

Then there are the questions of boundary, which are ever cropping up, for, as the United States mining law allows a lessee to follow the lode downwards wherever it leads, in doing so he often gets into other people's property. And Uien there is the question, What is a lode ? ' An American court, for example, has recently decided in the dispute between the Eureka (an American) and the Richmond (a British company) that the mass of mineralised limestone of Ruby Hill (fig. 41), a mass nearly as thick as the mass of our Northumberland or Denbigh-

The Purchase And Sale Of Mines. 4Oi

shire limestone, is a lode ! Of course, in such an unsatis&c- tory condition of the law, there can be no security for investors.

Then it must be confessed that the English management of mines in Western North America has been &r inferior to that of the Americans of their own mines.

We have often sent abroad mine managers, who, good enough in Cornwall, knew nothing of the different conditions of the ore deposits there. Well-intentioned and intelligent, too, as many of them were, they were under the direction of incompetent men, whose chief qualification for the post of general manager or managing director seems to have been that they had failed in everything else. If to all this we add the essential difficulties of mining, the distances to travel, the cost of carriage of materials, the temptation to agents to be careless and neglectful, and of workmen to skulk and be idle, we gain an idea of the difficulties that lie in the way of successful mining at a great distance from the seat of its direction.

On the purchase and sale of mines, — The reference just made to the extravagant prices paid for mines and mining properties naturally leads to a consideration of the principles that should regulate the purchase and sale of the same. I would here lay down two axioms — ist TTiey who take the risk are entitled to the profits of success; and, 2nd. Where nothing has been discovered that can be profitably worked there is nothing to pay for. The opinions of engineers or other mining authorities, however eminent, or practical, or experienced ; the parallelism or the continuation of a good lode, or the proximity of a property to a successful mine, whose chimneys can be seen — ground of recommendation given in a recent prospectus— are matters which should be duly considered by a man or a company who propose to spend money in exploring further, but they are not things to pay a premium of thousands of pounds for.

Some of the first questions to be asked by an intending purchaser should be — What proportion of the purchase-money will the ore now actually discovered, if it can be worked to a profit, pay ? and, what amount of ore will have to be raised,

D

402 Metalliferous Minerals And Mining.

and number of fathoms of ground cut away, before the amount of the purchase-money can be recouped, less the valuation price of the plant?

Now, supposing a lead lode is discovered that yields on an average 35 . of ore per fathom to the usual proportion of productive groimd, we can hardly, in the present state of mining, calculate upon a greater profit than 2/. per fathom of ground cut, at an average seUing price of 10/. lox. per ton. If a copper lode worth 4 tons of ore of 6 per cent quality is discovered, we cannot reckon upon a larger profit than 2/. per fathom (if we can as much), at a seUing price of i2x. per unit Now, in each of these cases, for every 1,000/. of purchase-money paid, 500 fathoms of the lode will have to be cut down. If the purchase money amounted to 70,000/., as in a recent sale of a copper mine it did, no less than 35,000 fathoms of the lode would have to be extracted before the purchase-money could be repaid. If the profit could be estimated at 3/. per fathom, then 330 fathoms, if at 4/. per fathom, 250 fathoms of the lode would go to pay each 1,000/. of the purchase-money.

An orinal discoverer should, of course, be remunerated for his trouble, intelligence, and expense in making such discovery. The fairest way to do this is by giving him a share in the future success of the mine. If we double the actual cost he has incurred, always supposing the money has been judiciously expended, then whatever proportion this augmented sum bears to the capital actually required for the working of the mine should, I think, determine the amount of share he is entitled to. For example, if he has actually spent 500/., we double it for him on account of the risk he first incurred, making 1,000/. If the capital of the mine is ultimately 5,000/., he is entitled to one-fifth share. This rule, which to me appears £ur, may be readily applied to larger transactions.

But a vendor or vendors should not be allowed to throw their shares on the market, except by special arrangement, until the mine pays its cost

In the case of the transfer of a mine in full work, and paying an annual income, the price to be paid should not, I think.

Essentials Of Successful Mining. 403

exceed five years' purchase, added to the valuation price of the plant Thus, if a mine is returning a clear income of 2,000/. a year, its price should not exceed 10,000/., added to the price of the plant as valued for transfer.

If we look at the mine reports which appear in the mining papers we shall observe a large number of mines whose stopes are worth from 15 to 25 . of lead ore per fathom, with, perhaps, a little blende, a ad which do not pay. I feel little hesitation in saying that they ought to pay a modest profit on the capital actually necessary for their development and working. For example, take an average of one ton of ore per fathom, worth 10/. I ox., taking one time with another ; let there be the ordinary quantity of barren ground; pay 50;. per fathom for stoping; add SOS. more for development; add 50J. for dressing and for management; this makes 7/. lor; put the cost, if we will, at 8/. I Of., and it will be seen that when the mines are opened such mines ought to pay.

The sources of failure I have indicated naturally suggest their remedies. We want a more intelligent class of miners — I mean in their own business. Why should not every elementary school in a mining district have a section of the ground below, with its lodes and mineral zones defined on it, hung on the walls ? Can we not spare some of the general knowledge required in our school standards, or in the special subjects,' for the sake of local technical knowledge ?

We want, also, a more intelligent race of mine captains and engineers. I feel ashamed, sometimes, when I think how German mining engineers may read the reports of some of our mine captains and experts on mineral properties. Still, great advances have been made of late years, and with more field and underground work, added to the teaching of our schools of mines and local mining schools, we should soon take what we ought to aspire to — the firont rank as miners.

Then we want ordinary business principles and honesty applied to the outside management of mines and to their purchase.

These requisites are surely attainable, and they would, as

Dd 2

404 METALLIFEROUS MINERALS AND MININa

we have seen, alter very materially the proportion of profitable to unprofitable mines.

Then a fiuther reduction in the cost of mining may be made by new explosives, by rock drills, and by improved pumping and dressing machinery. Thus, the cost of the production of tin in Cornwall has been reduced by quite onefourth of late years, at the best mines. The same reduction may be made in the cost of lead and copper. If it is made, and it can and must be made if we are to compete with other nations, we have many years of increased mining prosperity before us.

I would emphasise what I have already said, that mining is a business for the strong, the adventurous, and for the men who can spare money, without the possible loss of it hurting them. No one is justified in investing in mines the source of a scanty income, or money that is needed in his own business. If such people lose their money they have themselves alone to blame. For the others, it is a pursuit of pleasurable excitement, of intelligent activity, of ample scope for inventive genius, and of at least ordinary chances of success. It is an honourable pursuit j for he who wins the ' precious things of the everlasting hills ' fiilfils no common part in the economy of the world.

Glossary

Op Words And Terms Used In Mining, And Of Scientific Words

Used In This Book.

Abbreviations. — Am,f American; Aus,, Australian; C, Comisk; D.f Derbyshire; /!, French; G., German; N,, Nh of England ; S., Spanish; IV., Welsh.

Abbruch. G. Ore broken off the lode or deposit

Abendort. G. The end of a mine towards the setting sun,

Abendschicht. G. Afternoon shift or company of miners.

Abendstoss. G. The western end of a mine.

Abfullen. G. To draw off a good body of ore.

Abflanherb. G. a huddle.

Abkomniss. G. The junction of a tributary with a main lode.

Abra. S. a hollow, opening, or fissure on a lode.

Abronziado. S. Yellow copper ore, sulphides.

ACCOMPT. C. Account day, the usual settling day ; the place of

meeting, or account house. AcHiCAR. S. Term expressing the decrease of water in a mine. AcicuLAR. Needle-shaped. Ademar. To timber. Ademador. S. a timberer, or mine carpenter. Adit. A level driven in the side of a hUl, and opening out into

daylight Addlings. N. Earnings. Adulari A. A hard translucent variety of felspar containing much

orthoclase. See ' Orthodase,* also ' Felspar.' Adventure. C. A mining enterprise, a trial. Adventurers. The original promoters or speculators in a mining

trial. Ahondar. S. To sink.

Air Machine. A machine for creating ventilation in mines. Air Pipes. Pipes of metal or wood for the conveyance of air. Air Stack. A chinmey built for ventilation.

406 Glossary.

AiTCH Pipes. The parts of a pump-lift in which the valves are

fixed. ALBAJIL. S. Mason. Albayalde. S. White lead. Alcam. IV. Tin.

Alive. C. The productive part of a lode is said to be alive. Alluvium. The mud, silt, and gravel deposited by rivers and floods. Almadeneta. S, a stamp head. Almagra. S, Red ochre.

Amalgam. The compound of mercury with gold or silver. Ammonia (Muriate o. Chemical composition, ammonium 337,

chlorine 66*3. Amygdaloid. The name given to igneous and metamorphic rocks

having almond-shaped substances distributed throughout them. Anticunal. When strata dip away from each other, as in fig. 89,

they are said to be anticlinal. Arenaceous. Sandy. Argillaceous. Clayey. Arian. IV, Silver. Arrage. N, Sharp point or comer. Arragonite. Needle spar, carbonate of lime mixed with ci to 4

of carbonate of strontia. Arrastrar. S, When veins unite or are drawn together. Arrastre. S. An appliance for arresting the particles of gold

and other ores in the process of washing. Arroba. 5". A Spanish weight "25 lbs. Asbestos. A fine elastic fibrous variety of hornblende, in colour

ranging white, grey, and green. Ash. The name by which igneous, eruptive, and metamorphic

rocks are known when they are of an ashy or cindery nature. ASPIRAIL. P, An opening for ventilation. AsTYLLEN. C A small dam in an adit; a partition between ore

and leads on the grass. Attal, Addle. C Valueless refuse filling old mines ; stony

matter about ores. AUGITE. Chemical composition, silica 56*36, lime 25*46, magnesia

18*18, varied by small portions of the protoxides of iron and

manganese. AuR. JV. Gold. Auriferous. Containing gold. AUSSCHAREN. G. The junction of lodes.

Glossary. 407

AusziMMERN. G. Timbering.

Axis. The central part of an anticlinal, as at figs. 37 and 89.

Back of a lode the portion of a lode lying between a level driven

in a lode and the surface. Backing. The timbers fixed across the top of a level, let into

notches cut in the rock. Back-shift. The second or afternoon set of miners. Bal. C. Commonly a mine. Strictly the outside of a mine)

especially when located on a hill. Balland. D, Finely separated lead ore. Bancos. Rocks crossing a lode, or diverting it from its ordinary course. Bank Claim. Aus. A mining right situated on the bank of a

stream. Bank Right. Aus, The right to divert water to a bank claim. Bar. a band of hard stone or rock crossing a lode. Bargain. A portion of a mine let to a gang of miners to work at

a price agreed upon. Bar Master. D. The Derbyshire name for a mine manager,

agent, and engineer in one. Bar-mote. D. A cotirt where matters relative to mines are tried

or considered. Barranca. A ravine.

Baryto-calcite. a mixture of carbonate of baryta and carbonate of lime — occurs as yellowish white transparent crystals. Basalt. A mixture of augite and felspar with some iron. A dark

green or black stone occurring in large crystals or columns, like

those of the Giant's Causeway. Basset. The outcrop on the surface of a lode or bed. Beat. C To stope or cut away a lode.

Bed-claim. Aus, A mining claim lying on the bed of a stream. Bed-rock. Aus, The strata immediately underlying loose or

drifted matter. Ben. C. Alive. The live or productive part of a lode. Ben-heyl. C, a live stream, where tin is found. Binder. C. The underground carpenter who binds or secures

the mine. BiNG-ORE. D. Lead ore in small lumps or cobbles. Black Jack. An ore of sulphide of zinc, blende— mock lead.

408 Glossary.

Black Sand. Aus, The name given to black tin, iron, manganese, and other ores usually accompanying gold. Black Tin. C. Dressed tin ore. Blanket-table or Strake. Aus, A sloping board or table

covered with green baize for the purpose of intercepting gold. Blind Creek. Aus. A creek dry except in wet weather. Block Claim. Aus, A square mining claim defined by posts. Blocking out. Aus. Washing auriferous drift in square blocks. Blue Elvan. C Greenstone. Blue-John. D. Fluorspar. Boca. S. Mouth of a mine. Bocamma. S. Mine opening. BoLSA. S. Name given to a small bunch of ore. Bonanza. S. (Prosperity). Name given to large deposits of

good ore. Bonze. Undressed lead ore. Borrasca. S. Adversity; name given to a mine when in an

unproductive state. Botryoidal. Rock showing the structure or appearance of that

of a bunch of grapes. Bounder. C. The owner of a small patch of ground called a

' bound.' Brace. C. The ground and buildings around the principal shaft

of a mine. Branch. Small string of ore connected with the main lode. Brazil. N. Iron pyrites. Breccia. Rock composed of angular fragments of rock cemented

together. Brooch. C. A mixture of various ores. Brown Spar. A variety of dolomite made up of carbonate of

lime, carbonate of magnesia, and from lo to 20 per cent of

carbonate of iron. Brylr. Surface indications of a lode, in decomposed mineral

matter. Bucking. Breaking ore — with a flat iron fixed on the end of a

stick— ready for the jiggers. Bunch. A rich deposit of ore. Bunding. A staging of wood over a level or road in a mine on

which rubbish from the stopes is thrown. Bunney. a pocket or considerable mass of ore not lying in a

regular vein.

Glossary. 409

Burrow. A heap of deads or refuse on the surface. BuscoNES. S, Miners who work on tribute explorers for minerals, workers of old mines.

Cal or Gal. C. A hard rusty-coloured stone containing iron, found in poor lodes. (Welsh, ca/edy hard.)

Calcite. Calcareous spar, carbonate of lime ; chemical composition, lime 56*0, carbonic acid, 44*0.

Callys. C. Killas applied to the slaty stratified rocks traversed by lodes.

Cam. a long curved tooth fixed on a shaft for the purpose of raising a stamp. (Welsh, cam crooked.)

Cank. D, Whinstone, or band of hard rock.

Canon. S. A deep valley.

Caple. C. a hard stone lining the sides of tin lodes.

Captain. The overseer or practical manager of a min&

Carat. Term used for denoting the' quality of gold. English standard gold contains 22-24ths of pure gld.

Carbonaceous. Containing carbon in the shape of vegetable remains.

Carbonate of Baryta. Chemical composition, baryta 777, carbonic acid 22*3.

Carbonate of Strontia. Chemical composition, strontium 70*2, carbonic acid 29*8; occurs as resinous fibres with a radiated structure.

Carbonic Acid. Chemical composition, carbon 27-65, oxygen

Carboniferous. Containing carbon, as Carboniferous Limestone.

Carga. S. a mule's load - 380 lbs. Spanish.

Carn. In ancient British a monument, a heap of stones.

Carreg, Cmao. IV, Rock.

Cascahlo. S'. On a mountain applied to stony strata.

Cases. C Fissures through which water runs into a mine.

Cast after Cast. C, Throwing up ore from one stage to another in an excavation.

Catear. S. To search for minerals.

Gaunter. C. Contra, a smaller lode running diagonally across the main lode of a mine.

Caxo. S, a measure of ore containing at Potosi 5,000 lbs.

410 Glossary.

Cefn Ceffyl. W. a hump on one of the walls of a lode, nearly

cutting ofif the ore. Cellular. Containing numerous cells or cavities. Centner. G. The hundredth part of anything. Chapas. Iron blocks holding the ore inside the stamps. Chert. A mixture of fine silica or sand with a portion of lime,

and ocouring in a hardened form. See ' Homstone.' Chlorite. Chemical composition, silica 32*2, alumina 18*3,

magnesia 357, water 13*8, varied with small proportions of iron Clavos. 5". Masses of ore, and of native metals, Cleet. D. a wedge.

Cob. C. To bruise or break ore into ' cobbles ' or small lumps. Cockle. C. A earthy mineral, like tin, but worthless, and disappointing from its resemblance to the true

mineral Coffin. C. Name given to old open excavations. Colorados. .S". Red ores, coloured with oxide of iron, like gossan. Conglomerate. Rock composed of rounded and water-worn

stones cemented together. Coralline. Partaking of the structure of corals ; coralline limestone. Corundum. One of the precious stones, composed of alumina,

with peroxide of iron, or other colouring matter. CORVE. A small waggon used for drawing minerals underground. COSTEAN. C. {cothasy find, stean tin). To costean is to search

for a lode by sinking small pits along its course on the

surface. Country. C, The strata through which the lodes traverse, or

in which ore deposits are found. Course. C, i. Vein or lode. 2. Direction taken. Crab Hole. Bay of Biscay country. Aus, Holes, apparently

water-worn, met with in the bed rock under the drift, which

are often the cause of fatal accidents. Cradle. Aus, A wooden box used in gold washing, as already

described. Cpeazes. C. Name given to portions of ore in buddies. Creek. Aus. Small gully or brook feeding a river. Crop. C Name given to tin ore when dressed. The finest

black tin is called crop, and its value is computed at one half

that of the finest grain tin. Cross Course. A cross vein.

Glossary. 41 1

Crosses and Holes. D, In Derbyshire the discoverer of a lode secures it temporarily by making crosses and holes in the ground.

Cross-cut. A level or tunnel driven towards alone at right angles to its course.

Crystalline. Greek {KrustaHos, ice). The name given (i) to substances when crystallized into definite shapes as described on page 3. (2). As used to describe the internal structure which crystallized substances show on being broken. Loaf sugar, for example, has a crystalline texture.

Cut. To cut a lode is to intersect it at a right angle to its course.

CwLWM. W. A band or pillar of rock, cutting off the lode.

Dam. D, a barrier to keep back bad air or water.

Damp. Bad air — choke damp, fire damp.

Dan. a tub or corve without wheels ; a sledge.

Day. Near the surface, where daylight penetrates.

Dead Ground. Parts of a lode without ore.

Dead Men's Graves. Aus, Humps in the basaltic rock, under the auriferous drift, like graves.

Deads. Earthy materials without ore — rubbish, refuse.

Dean. C. The end of a driving.

Derrick. C. i. Miner. 2. A pulley fixed on poles, over which a horse draws a rope by walking forward.

Desaguador. S. a pipe or drain for conveying water.

Desmonte. S. Clearing away the surface rock ; breaking ore.

Dessue — DizzuE. C. To cut dovm the ground by the side of a thin lode in order to take the latter down whole ; hence DzhUy to undermine a portion of the rock to be blasted whole ; Cornish, Dyshue, to lay bare, to disarm.

Diagonal. Greek, diay through, goniciy comer. From comer to comer.

Dialling. The process of surveying a mine with a dial

DiLLUEiNG. C, To wash small ore in a fine sieve.

Diorite. a greenish granular rock composed of silica, felspar, lime, alumina, magnesia, and iron. A greenstone.

Dip. The slope or inclination of a lode or bed from a horizontal line.

Dippa. C a small pit simk on a lode to catch water ; a pit sunk on a bunch 01 e.

412 Glossary.

Dish. C, A vessel or trough in which the proportion of ore doe to the lord of the manor or owner of the soil is measured. In lead mines a trough 28 inches long, 4 inches deep, and 6 inches wide. A gallon measure.

Disk. The projecting plate on a stamp shaft caught by the cam.

DOL. Welsh and Cornish for meadow. Dolcoch oxDolcoath red meadow.

D6l. a ' dole ' or share in an undertaking or property.

DOLERITE. A variety of basaltic rock ; a compact mixture of augite and felspar, sometimes granular in structure, but often showing no grains.

Dolly. Aus, i. An instrument used for breaking and mixing day in the puddling tub. 2. A log of wood shod with iron, and hung from a tree over a hole ; formerly used for crushing quartz.

Dolomite. Bitter spar. A mixture of carbonate of lime with more than 20 per cent of carbonate of magnesia, and from 10 to 20 per cent of carbonate of iron, forms a compact creamcoloured limestone.

DONK. N. Doughy, clayey, or soft earth, found in cross veins and fiats.

DowsiNG-ROD. A rod, usually of hazel, by which formerly explorers were thought to be able to discover a lode by the tendency of the rod to be inclined by attraction towards it

Dresser, i. The superintendent of persons employed in picking, washing, and dressing ore. 2. Those persons themselves.

Drift. A tunnel driven from one part of a mine to another.

Dropper. A course of ore leaving the lower side of a lode.

Due. The amount of royalty or ore payable to the lord of the manor or owner of the soil

DuMB'D. When the grate or sieve in which the ore is dressed is choked up.

DuRR. G, Barren part of a lode or ground.

DuRGY. C Anything low or short

DURNS. C. Wooden frames like door frames set in drivings where the ground is loose and weak.

Dyke. i. A band of hard tock, usually igneous. 2. In the North of England a fault is called a dyke.

Efydd. W. Copper.

Glossary. 413

Elbow. A sharp bend in the ordinary course of a lode, from which the latter soon recovers.

Elvan, or Elven. C A band or course of hard felstone or porphyritic rock.

EmbonanzAl. S, When a mine is being worked to profit

Emborrascarse. 5. A barren part of the mine.

End. The farthest end of a driving.

Entblossen. G. Uncovering a lode.

Epidote. a mixture of alumina and silica forming a variety of garnet ; often of beautiful colour and shape. Chemical composition : silica 37*0, alumina 26-6, lime protoxide of iron 13-0, protoxide of manganese 0*6, water i*8.

Erbhefste. G. The deepest part of a mine.

Eruptive. The name given to rocks that have burst through other rocks in a molten state, or that have been thrust up bodily.

"ESTANO. S. Tin.

Exempted Ciaim. Aus, A mining daim allowed to stand idle for a time by a certificate firom the registrar, as provided in mining law.

Eye. A. The top of a shaft or pit

Faiscador. S, a gold washer.

False Bottom. Am, Aus. A loose plate put into the stamp

box ; a floor of iron placed in a puddling machine ; a bed of

drift holding auriferous drift, and overlying the bed of the

latter that usually lies on the bed rock. Fan EGA. S. A measure equal to an English busheL Fanegado. S. a land measure 90 £uiegados-iiqp English acres. Fang. C. An air course along the side of an adit or shaft. Farm. C. The fee payable to the lord of the manor or owner of

the soiL Fast. C. The solid rock inmiediately under the sur£Eu:e drift. Fathom. Six feet ; a cubic £5tthom 6 feet n 6 feet x 6 feet is the

measure of work in most mines. Fault. A Une of disturbance or dislocation in strata. Feeder. A branch coming into a lode firom the upper or hanging

side. Feigh. Ore reftise. Felspar. The name given to a common constituent of many

rocks. It is an intimate mixture of fine silica 60 parts, alumina

414 Glossary.

1 8, potash i6, with a little lime and some iron. Most of the clays used to make bricks are decomposed felspar. In colour it is white pinlc> It can hardly be scratched with a knife.

Felstone. a very compact and uniform kind of felspar.

Ferruginous. Charged with iron.

Feuressenarbeit. G. Fire-eating work, working upwards towards the surface.

Flang, C. a pick with two points.

Floating Reef. A us. Loose masses of auriferous rock.

Flookan, or Flucan. C i. A vein filled with dayey matter crossing the main lode. 2. A parallel vein of the same character. 3. A lode containing a preponderance of day is called a flookan lode.

Floor. Where the lode is bent flat in its downward course and appears like a bed.

Floran. C. Very fine tin ore, sometimes called flour tin.

Flour Gold. Aus, The finest drift of gold.

Flouring. Aus. The covering, in the course of using, of the globules of mercury used in gold extraction with a thin film of the sulphide of some other metal, by which the power of the mercury to intercept gold is lost ; also called ' Sickening.'

Fluke. A rod used for cleaning drill holes before they are charged with powder.

Flume. Am. An artificial watercourse at hydraulic gold mines.

Fluoride of Calcium. A mixture of the two simple dements of fluorine and calcium.

Fluthwerk. G. Searching for ore in streams and river beds.

Foot. C. An ancient measure containing 2 gallons, or 60 lbs., of black tin.

FooTWALL. C. The imder or heading side of a lode.

Footway. Shaft with ladders and stages used only for descending and ascending mines.

Force Piece. Timber placed diagonally across a shaft or drift for securing the ground.

FoRCQUE, or Fork. C. The bottom of the sump, in which the water is collected at the bottom of a mine. In Derbyshire a fork is a prop for keeping up soft ground.

FOSSICKER. A sort of mining gleaner who picks the crevices and cavities of the rocks after the miner.

Founder's Shaft. The first shaft sunk at a mine.

Glossary. 41 5

Frame, or Rack. C A gently-sloping board for washing stream

Friable. Easily reduced to powder. Fundamental. A name appUed to the lowest or basement strata

of the earth's crust as far as at present known, as i and 2 in

fig. 37. Furnisher. A man who furnishes money or machinery to a party

of miners, and so becomes entitled to a share of the profits.

Fuse. The prepared tape or cord by which fire is conveyed to the

charge of explosive to be ignited.

Gad. C. A wedge for splitting rocks. Gal. C a hard rusty gossan— (Welsh, hard). Galena. Sulphide of lead — the ordinary lead ore of commerce. Gamela. S, a large wooden bowl used in dressing ore. Gang, or Gangue. G. The non-metallic material filling lodes. Gangway. A roadway through the deads or rubbish in a mine. Garnet. A stone valued for its colour and transparency. It is a

mixture of silica, alumina, and the oxides of iron and manganese. See ' Epidote.' Gatches. C. The final sludge or leavings of tin. Gefarht. G. The course or direction of a lode. Girdle, or Girdle Beds. N, Thin beds of hard close-grained

sandstone separated by shale. Glaucodote. a mixture of sulphur with 11 '9 of iron and 24*8 of

cobalt. Glist. C a dark-coloured ferruginous mineral found in lodes —

micaceous iron ore. Gneiss. A rock composed of quartz, mica, and felspar, in which

the different parts are arranged roughly in layers. Mica

usually prevails. Gonge. Am, The soft clay lying between a body of ore and

the sides of the lode or cavity. Gossan. C The name given to quartz, calcareous spar, and other

substances filling a lode when charged and coloured with iron

ores. Grain Tin. C. i. Tin ore obtained in grains or pebbles. 2.

Finest smelted or block tin. Granite. A rock like gneiss, composed of quartz, mica, and felspar,

but the particles or granules are all mixed up together indis-

4l6 GLOSSARY.

criminately. In colour, white when quartz prevails, red when

there is much red felspar, and green sometimes from the

presence of chlorite. Grant. Land granted to adventurers for mining purposes. Granular. Made up of grains or granules. Granzas. S. Poor ores. Grass. The sur&ce of the mine. Ore brought to grass is ore

brought to surface. Grate. A perforated plate or iron frame with bars used for

separating and washing ores. Greenstone. The name given to a variety of rocks (see Diorite ;

but some greenstones are very close-grained and compact, as

if they had been in a molten state. Grena. S. Undeaned rough ore. Greisen. The conunon Saxon name for grey-coloured granitic

rock. Griddle. A larger form of grate. Grits. Coarse sandstones. Groove. D. A mine. Grouan. C. The conunon Cornish name for granite and granitic

rocks in Cornwall. Ground. Name given to strata bounding a lode, synonymous

with Country.' Grube. G. Mine. GUAG. C. An empty space, or place from which the ore has

been extracted. (From Welsh, gwag - empty.) Guarda. a thin parting between the materials of a lode and the

country. Gulch. Am. A deep ravine. Gully. A us. The feeder of a creek. GULPH. Of ore, a large body of ore. Gunnies. C. Name given to width — one gunnie 3 feet. GURT. C. Chaimel to carry water from dressing floor. Gutter. Aus. The lowest portion of a gold digging, or lead

filled with auriferous drift that rests upon the solid rock.

Hacienda. S. House where ore is smelted. Hade. The dip or underlie of a lode. Haiarn. IV. Iron. Halvanner. C. a dresser of halvans.

Glossary. 417

Halvans, Halvings, Hanaways. C, Poor or refuse ore after the best is taken out, usually applied to refuse copper ores.

Handfarht. G, The descent into a mine by ladders.

Handwhip. Aus, a contrivance for lessening the weight of water lifted out of a digging by means of a lever and weight fixed to a flexible tree.

Hanging Wall. The upper side of a lode.

Harrow. Aus, A pole with teeth fixed on it turned round in a puddling machine to mix auriferous clays water.

Hauling. Bringing stuffto the surface.

Hazle. a tough mixture of sandstone and shale.

Heading-side. The imderside of a lode.

Head Sword. Water discharged through the adit level

Heaves. Faults by which the lode is thrown upwards.

Heavy Gold. Aus. Shotty gold ; particles of gold the size of gun shots.

Heavy Spar. Sulphate of baryta.

Hechado. S, The dip of a lode.

Hilo. S. a thin metalliferous vein.

Hoggan. C The food carried by the miner to the mine.

Hole. To ' hole ' is to make an opening from one part of a mine to another; to pick out the soft underside of a lode or bed preparatory to wedging or blasting the remainder down.

Horizon. The name given to the place occupied stratigraphically by a bed or series of beds of rock.

Hornblende. The name applied to a group of substances, the general composition of which consists of silica 40 to 50, aluminum o to 17, lime o to 50 iron protoxide o to 50, manganese o to 4, potash o to 3, soda o to 8, fluorine o to 1, and a little water. Hornblende varies in colour from white through yellow to green and black. The common varieties are of a greenish cast

HORNSTONE. A hard silicious rock-like flint See ' Chert'

Horse. C. The dead or barren ground by which a lode is sontetimes split into two.

HuEL, or Wheal. C. A mine work.

Hulk. To hulk a lode is to pick out the soft or best part with picks, leaving the hard portion to be blown down with explosives.

Hurdled Ore. Ore passed through a coarse screen, like a mortar screen.

e e

41 8 Glossary.

G, Fumace or smelting house. Hydraxtlic Hose. Am, The flexible hose now used to direct a stream of water against a wall or £aice of drift

Igneous Rocks. Rocks formed or altered by the action of fire.

Inch— Miner's. Am, A miner's inch of water is the quantity of water which will pass through a horizontal sUt one inch wide and twenty-four inches long, with the water in the reservoir standing six inches above the hole. The quantity discharged in twenty-four hours is equal to 2,274 cubic feet.

Intrusive Rocks. Rocks that have been thrust through other strata.

Irestone. C. a hard tough stone, usually greenstone.

Ironstone Casing. Aus The casing of ferruginous matter usually auriferous, found abutting on quartz reefs.

ITABIRITE. S. Micaceous iron ore.

JAOOTINGA, Jacotings. S. Tne various coloured iron ores associated with and often forming the matrix of the gold in the Brazilian mines. So called from their resemblance to the colours of the plumage of the Brazilian bird, Penelope Jaootinga.

f ETTERS. C, TThe horizontal rods or poles connecting the water wheel and the pumps.

Jeweller's Shop. Aus, The name given to a very rich patch of gold drift

J igginGw a method by which the smaller kinds of ore are dressed, either with a sieve turned by the hand with a peculiar rotatory and vertical motion in water, by which the lighter earthy stuff is thrown off the ore; or the same process performed in a variety of ways by machinery.

Joints. The natural divisions or partings of strata.

Judge. A staff used for underground measurements.

Jumper. A drill used by one man by raising and falling.

Junction. The union oftwo veins or lodes.

Kau C Af/'Caland'Gal.' Kann. C. The Cornish name for fluorspar. Kaolin. China or porcelain clay. General composition silica 47'2, alumina 59*1, and 137 water. .

Glossary. 419

Kazen, C. a sieve.

Keeker. An overlooker.

Kerned. C. Copper or mnndic ore hardened by exposure to

the sun. Kernow. C Cornwall

Kevil. D. Spar found m the lead veins of Derbyshire. KiBBAL, or Kibble. The bucket or small barrd used to draw

materials out of a mine. KisvEy or Keeve. C. The tub in which tin ore is finally tossed

or towed. KiLLAS. C The hard shale or slate traversed by lodes, KiNOULLY. C. Loose crumbly ground. Knocking. See ' Cob.'

LAcHB, /% Dross*

Lama. S, Fine ore as mud.

Lander. C. The banksman who receives and empties the kibble

at the top of a shaft. Lappior. C. The old name given to those who formerly dressed

ore with their feet in a buddle— dancers; now applied to

dressers of ore. Launders. C The troughs by which a stream of water is con<

veyed to the water wheel, or to any part of a mine. Lavador. S, a washer of gold after amalgamation* Lavadoros. S. Gold washings. Lavour. F. a buddle for washing ore. Lead. Aus, An undergroimd course of aurifierous drift generally

follows the course or bed of an andent stream A string

or course of ore. Leader. C. The same. Leading. Z>, A small sparry veiiu Learys. C Emptiness. Old mena wot kings. Leat. a water-course for conveyance of water to a mine.. Leavings, See Halvans. Lenticular. Onion-shaped. Name given to masses of different

material found in the midst of rocks. Level. Name given to a driving or adit underground, along the

course of a lode. Levelling. The art of finding the level of one place compared

with that of another.

Se2.

420 Glossary.

Ley de OrO| or De Plata. S, The quantity of gold or silver in

the ore. Limp. An iron tool for separating the refuse from the ore in a

mine. LlNGULiDiC The name given to a family of ancient shell-fish firom

their resemblance in shape to a tongue. Little Winds. A lesser or subsidiary shaft in a mine. Lob of Gold. Aus, A rich deposit of gold within a small area. Loch. IV,&-D. A cavity in a lode ; a vughJ Lode. Anglo-Saxon lead ; to lead ; lode-stone ; a vein or course of

material different from the enclosing rock, as explained in the

text; a fissure or crack filled with matter, which may or may

not be charged with metallic ore. Lode Plot. A horizontal or flat lode, or one nearly so. Lofty Tin. C, Large and rough tin ore. Long Tom. Am.&*Atts. A trough for washing gold, as described

in the text. LOORS. C. The sludge lefi after washing tin ore. Lord. C. Landlord ; the owner of the soil or mineral, to whom

rent or royalty is payable. Lost Slovan, Low Slovan, Lode Slovan. The open trench

leading to an adit Loth. G. A German weight, about half an English ounce.

Macizo. S, An unworked part of a lode.

Mad Water. C. Water that, through nlect, rushes back to the mine.

Magnetism is the name given to the power whereby a magnetic ore of iron, the lodestone, attracts and retains iron and steel ; to iron in its latter form it imparts this same power.

Magnetic Force is the name given to the tendency which magnetic minerals like those just described have to move, or incline or lie with their length pointing towards that portion of the earth known as the Magnetic Pole.'

Magnetic Pole. A point on the earth's surface at present a lite to the west of the North Pole or end of the earth's axis, and towards which magnetic currents ever flow through the mass of the earth. It is a variable point In 1580 this spot was 1 1 degrees to the east, in 1669 it was af the true pole, and in 1835 it was 22 degrees west of the latter.

Glossary. 42 1

Manganese Peroxide. Two parts of manganese combined with

three of oxygen. Manto. S. a single bed or layer of strata. Marco. S. A weight 8 ounces. Maza. S, a stamp head. Mear. D. a measure along the vein of 32 yards. Meat Earth. C The surface soil that may be cultivated. Metamorphosis. From the Greek, denoting a change of substance or structure. Metamorphic, Metamorphosed. Of an altered character ;

changed. MiA-MiA. Aus. A screen of brushwood, supported on poles, and

placed near a shaft to protect the men from the weather. Mica. A conunon constituent of granite and gneiss, composed of

about — silica 48, alumina 39*8, and potash 12*2. Mice-eaten Quartz Ores. Quartz full of holes, once occupied

by sulphides, now decomposed and gone. Mock Lead. C. Name given to blende, also called wild lead.' Montana. S. A mountain. MoNTON. S, A pile of ore, the weight of which varies in the

various mining districts of South America. MORR. C. A gathering of ore in a particular part of a lode. MUESTRAS. S. Samples of ores. MuN. C. A metal or a mine. MUNDIC. Cornish for any pyrites, more correctly applied to

arsenical pyrites ; the common ore of arsenic. MUSCHSLRALK. The name given by the Germans to a limestone

lying in the midst of the New Red Sandstone or Triassic

strata. Supposed to be absent from the ' formation ' in Britain. MwYN. IV. Mine; ore.

Nebengang. G. a side lode.

Needle. A pricker ; a slim piece of round iron used for making

touch-holes for blasting rocks. Nitric Acid. A mixture of nitre with sulphuric acid. NITRO-HVDROCHLORIC AOD. A mixture of nitric acid with ' miuiatic or hydrochloric acid— the latter in its common form

being known as spirits of salts. NiVELS DE Aqua. S. Water levels. NOCKING. C. See ' Knocking,' or ' Cob.'

42Z Glossary.

NoGER. A drill commonly used as a jumper. NoRiA. S. Buckets fixed on an endless chain for lifting water out of amine.

OlTAVO. S, About the eighth part of an English ounce.

OjO. 5*. A bunch or spot of ore.

Old Men. The former workers of a mine. The workings left by

them are the ' Old Men's Workings/ or as in Derbyshire, ' The

Old Man.' Ore. The substance specially containing metaL Ore Plot, Ore Bin. The place where the dressed ore is kept Orpailleur. A gold washer. Oro. S. Gold. Orthoclase. The name given to transparent or translucent

crystals of felspar, of red, yellow, grey, or green colours.

Usual composition, silica 65*4, alumina 18, and potash

with variable quantities of soda, lime, and iron peroxide. Overlapping. When a group of strata passes over one or more

intermediate groups, and finally rests upon one much older, it

is said to overlap. Ovoid. £gg-shaped

Packing. C The final dressing of tin or copper ore in a large

vat or Ideve filled with water. Paoos. S, Mixtures of oxides of iron with ores of silver, usually

of a red colour, near the surface. As Colorados or Gossans. Pair, or Pare. C A gang of miners of indefinite number, often

five. Paleozoic Ancient life. The name applied to the strata containing the remains of the earliest organic beings. Palma. S. Quarter of a vara, or Spanish yard. Pannio. S. The strata traversed by a lode. Parcel. A quantity of ore ready for sale. Pass. An opening or small road left in the ' deads ' of a mine for

communication between the face of the stopes and the level

below. Peach Stone. C. A greenish-coloured soft stone; chloritic schist Pee. D, a piece of lead ore. Pen, or Pednan. C. (Celtic for head, or top.) i. The upper part

of a buddle. 2. A deposit of ore selected from a lode.

Glossary. 423

Pepenado. .S*. Cleaned ore.

Pepenadores. S, Ore cleaners.

Permian. The name given to the strata lying above the Coalmeasures. From the ancient kingdom of Perm, in Russia, where these strata are much developed.

Peroxide of Iron. Tluree parts of oxygen to two of iron. See ' Sesquioxide.'

Pick. i. An ordinary tool 2. To pick good ore out of a heap, hence pickers.'

Pilch. C. A portion of the lode let to miners to raise ore from on tribute.

Pile. i. As parcel 2. A pointed piece of timber. In Australia, a digger who has made money has made his ' pile ' of ore.

Pillar. A part of the lode left standing to support the mine.

Pillion. C, Ore that remains in the slag after smelting.

PiNTA. S. The appearance of a sample of the lode by which the character of the latter is judged.

Pipe. C. A long bunch of ore in a lode.

Pisolite. A rock structure like that of the roe of a fish.

Placer. Am, Name given to gold diggings, or hydraulic mines.

Plata. S. Silver.

Plate. N. Compact shale, separable into thin plates, that divides the limestone beds.

Plomb d'OBuyre. Silvery lead dressed ready for refining.

Plombiferous. Containing lead.

Plot, or Plat. i. A place prepared to receive ore 2. A rough flat bridge over a stream.

Plump. Provincialism for ' pump.'

Plunder. G. Ore refuse.

. IV. Lead.

PocHERZ. G. Poor ore.

PODAR. C An old name*for copper ore.

POLVILLOS. S. Good ores.

POLVOULLA. S. Black silver.

Pol Roz. C a wheel pit.

Pol Stan. C. A tin pit

Porphyry — Porphyra, purple. The name originally given to a red rock, with small white crystals of felspar disseminated in it, derived from Egypt, and now used somewhat vaguely to denote rocks containing felspar, more especially the reddish varieties.

424 Glossary.

Posts. A. i. Fine shale beds separating limestone beds. 2. In

Welsh slate quarries, unproductive portions of rock. Potash. Two parts of potassium to one of oxygen. The potash,

or pearlash, of commerce is an impure carbonate of potassium. Pot Growan. C. Decomposed granite. Powdered Ore. Fine ore disseminated throughout a lode. Predras de Mano. S, Good pieces of ore, sometimes held

sacred. PrS. IV. Copper, or brass. Pricker. A thin rod used for keeping an opening through the

'tamping' in a borehole. Pride of the Country. C Rich bodies of ore near the surface. Prill. C i. A piece of pure metal after smelting. 2. To prill

is to add rich ore to a poorer sample to improve the quality

of the latter. Produce. C The proportion of metal to 100 parts of ore. Prospector's Claim. Aus, A larger mining claim than is

usually granted, and given to a prospector or discoverer of

mineral groimd. Protoxide of Iron. Two parts of iron combined with two

parts of oxygen. Pryan. Cornish for day. PUETAS. S. Strong rock enclosing a lode. Puddling Machine. Am. Aus. A machine used for mixing

auriferous clays water to the proper consistency for the

separation of the ore. PULGADA. S. An inch.

Pulveriser. A machine for grinding ores fine instead of stamping them Puppy. An underground tier or set of pumps. Purser. The accountant and cashier at a mine, or the treasurer

and secretary combined in one person. PUTZEN. G. Small irregularly deposited spots or bunches of ore. Pyroxene. See *Augite.'

QUAJADO. S. Dull lead ore.

Quarry Lode. C. A rocky lode, broken by joints.

Quartz. Pure silica in a crystallised form.

QUARTZITE. Rock with much silica in a partly crystallised fona

QUARTZOSE. Rock with a good deal of quartz in it.

Glossary. 425

QuELSCHWERK. G. Ore to be crushed.

QUEMAZON. S. The bare scorched appearance of the outcrop of a lode standing up above the surface of the adjoining land.

QUERGESTEIN. G. Strata crossed at right angles by a lode.

Quicksilver Cradle. See description in book. Chaps. xxxix and xL

QuiLLATE. iS". Same as carat,' further divided into four granos.

Quintal. S, Four arrobas, or 100 lbs. Spanish loi English lbs.

Quintal Metrique. F, 100 kilogrammes - 217 English lbs.

QuiNTLEiN. G, The of an English ounce.

QuiTA Pepence. S, a man placed at the head of a shaft to see that none of the ore is stolen.

Rabban. C. a dry yellowish gossan.

Race. A watercourse from a stream to a milL

Racking. The process of separating ores by washing on an inclined plane.

Raffain. C, Poor ore.

Rag Pump. C A chain pump.

Rake. C, A vein or lode. D. A fissure as distinguished from a fiat

Ramo. S. a branch from a main lode.

Real. S, i. A mining district. 2. of a dollar.

Rebosadero. S, The crest of a lode.

Red Rab. C. Red killas, or slaty rock.

Reed, Rush, or Spire. C A reed filled with powder to act as a fiise.

Reef. Aus i. The outcrop of strata. 2. Of a quartz bed, or vein. 3. Of a lode generally.

Reef Drive. Aus, i. A cutting through the bed rock in alluvial mining for the purpose of ventilation. 2. For seeking finish underground gullies.

Reef Wash. Aus, The auriferous drift spread over the ground near the junction of two underground leads.

Reuz. S. The wall of a lode.

Remolino. S. a bunch or mass of ore.

Rhomboidal. a rhomboid is a geometrical figure o, which has its opposite sides equal to one another, but all its sides are not equal, nor its angles right angles. It is into this form that rock masses are usually roughly divided by natural joints.

426 Glossary.

Rib. C, a loader, or string of ore in a lode.

Rip, Ridding, or Redding. Cleaning up anything.

RiDD. C A riddle ; a shaft or drift

Riddle, or Griddle. A house sieve.

Rider, j. A thin band, vein, or layer, lying a short distance from a lode or bed. 2. The rock lying between the two. 3. The earthy materials of a lode. 4. The rock or country enclosing a lode.

Ripple, or Riffle. Am,&Aus, A board or table with grooves cut in the bottom for the purpose of intercepting the amalgam of gold and mercury.

Rise. To work from the level upwards.

Rock Salt. The chief source of the salt of commerce. Its general composition is chlorine 60, sodium 40.

Rod Shaft. The shaft containing the pump rods.

Roof. See ' Back' — the part of the lode over a miner's head.

Roughs, or Rows. C, The second quality of cross tin.

R6y. C Awheel.

Rubble. D, Loose stones.

RULLERS. C. Underground workers with wheelbarrows.

Rumba de la Veta. S, The run or course of a vein.

Run. z. Run of a vein or lode. 2. When miners overrun their contract 3. When the sides or roof of a mine run in or foil together.

Sallbr. C I. A chamber in a mine. 2. A stage to work on.

3. A boarded channel for water to run in along the bottom of

an adit 4. The floor or stage on which the ladders rest in

a shaft. Sample. A portion of the ore by which its quality is to be judged. Scal, or Scale. C The falling, in flakes or scales, of the walls

of a lode after the mineral has been taken out Schist. A slaty kind of rock, which splits into thin plates along

the lines of its bedding. Often applied to imperfectly-formed

slate. Schorl. Of an ashy or cindery character. The name formerly

applied to the black tourmaline. Also applied to granitic

rocks with a preponderance of felspar. Scovan Lode. C. A tin lode. ScovE. C Very pure tin that hardly needs dressing.

Glossary. 427

SCUN. Z>. A small vein.

SCROWL. Loose stones of ore at the point where a lode is disturbed by a cross gossany vein.

Seam. C. A horse-load of tin.

Seat. The bottom of a mine or roadway.

Searge, or Serge. C. A sieve.

Sedimentary. Rocks formed by the deposition of sand, mud, clay, &C., in water, are called sedimentary rocks.

Segregation. A form of the law or process of crystallisation by which materials having a liking or affinity for each other segregate, or, separating from other substances, gather together in masses. -

Serpentine. A stone much valued in building decoration. Oi various colours, green predominating, and various shades ; capable of a high polish. Usual composition, silica 42*3, magnesia 44'2, protoxide of iron 0*2, carbonic acid 0*9, and water

12*4.

Serving. C A supply of tin ready for smelting.

Sesquioxide of Iron. Two parts of iron to three parts of oxygen.

Set. I. To set a price upon a share in a mine. 2. To set bargains or work to miners.

Sett. The ground taken by adventurers for mining exploration.

Shaft. A pit simk from the surface.

Shake. C A crack or fissure.

Shale. An imperfectly-formed schist

Shammel. a stage for shovelling ore upon, or for raising water.

Sheet. Aus, A solid body of pure ore filling a crevice.

Shelf. Aus. The uppermost broken surface of the rock under driftal matter.

Shepherding. Aus, Keeping possession of a mining claim by doing the least quantity of work on it allowed by law.

Sickening. See Flouring.'

Side Adits. A side passage sometimes made when the chief passage is choked with rubbish.

SiLlClous. Sandy, containing silica, usually flinty.

Sill. N, A threshold or flat surface ; a face of hard rock, as the Great Whin SilL

Sink. i. A sump, or sink. 2. To work downwards.

Skimpings. C. The skinmiings of waste off the body of ore lying in the kieve or vat

428 Glossary.

Skit. C A small pump for surface use.

Slide. A minor fault or disturbance in a lode.

Slime-ore. Fine ore mixed with fine mud.

Slocking Stone. A promising stone of ore.

.Slotten. C, Slovenly, muddy, sluttish.

Sluice. Am. Aus. A long trough with a loose, rippled bottom, or bottom with holes, for the purpose of catching gold.

Spangle Gold. A us. Smooth flat scales of gold.

Spar Dantygi. iV. Carbonate of lime as dog tooth spar.

Spar Siwcrl IV. Carbonate of lime as sugary spar; the favourite form for lead ore.

Spathic. Of a sparry nature. Carbonates of minerals are usually called spathic ores.

Splintery. Rocks that break up into splinters or long sharp fragments are called splintery.

Stalactite. Hanging encrustations of carbonate of lime, formed by the dropping of water, are called stalactites.

Stalagmite. The pinnacles or colunms of carbonate of lime formed on the floors of caverns by the water dropping from the points of stalactites, are called by this name.

Steatite. A stone, usually soft, with a soapy feel, which con* tains a good deal of talc Usually of a greyish green colour.

Stempel. IV, A wooden stage, on which to work above a lode.

Stope. The workings of a mine between the levels assume the appearance of steps or stopes, and the miners working at these are stoping or stepping. When the steps are overhead, like the underside of a staircase, they are overhand stopes ; when below the miner's feet they are underhand stopes.

Strake. Am, 6r* Aus, A long, slightly-sloping board or table, used for the separation of gold from small quartz, &c

Strek. C, Strake, as above, for washing tin ore.

Strick. C, To let a man down a shaft by a windlass.

Strike, i. The course taken by strata at right angles to their dip or inclination. 2. The course or direction taken by strata along their level line.

String. A thin course of ore.

Struck Out. C, Phrase used when a lode is struck out of its course, or lost

Studdle. Aus, a square piece of timber placed in the comers of a shaft between the horizontal framework.

Glossary. 429

Stulls. Timbers or staging on which rubbish is left in the workings of a mine.

Sturt. a bargain that turns out well for the miners.

Sulphate of Baryta. Chemical composition, baryta 66 sulphuric acid 34.

Sulphate. A of a metal with sulphuric add.

Sulphuric Acid. Contains hydrogen, sulphur, and oxygen.

Sulphide. A combination of a metal with sulphur.

Sumph, or Sump. A pit sunk from the bottom of a mine, either to collect water or to prove the lode to a lower depth.

Sun. N, a sun vein is a south vein.

Swallow. A large cavity in rocks, chiefly in limestonesy useful for draining water from mines.

S wither. Am. A term used in the Wisconsin lead ron to denote a crevice or crack branching from a chief lode.

Syenite. A granitic kind of rock in which hornblende takes the place of mica.

Synclinal. The downward curve of strata, as at 6, fig. 8a

Tailings Machine. Aus, A machine for dressing the tailings,

and for obtaining gold from the detritus brought from the

washing machine. Tail Race. The channel by which the tail or 'used' water flows

from a mill or mine working. Tails. Tin ore thrown behind the stamps to be treated again. Takers. Baigainers, contractors, men who take work in a mine ;

raisers of ore on tribute. Talc. Chemical composition, silica 62*5, magnesia and

water 3*6. Usually of a scaly nature, dividing into thin flexible

transparent plates, which are occasionally tinged green or

yellow ; of a soapy feeL Tamping, Stemming, i. FiUing a hole, in which an explosive

has been placed, with day or other matter, which is rammed

tightly down. 2. The material used is called tamping, and the

bar or rod used is a tamping bar. Teary Ground. Ground that will tear or break up easily. Tepelate. .S". Barren ground; refuse. Testera. S, a dyke interrupting the course of a lode. Ticketing. The purchase of ore at periodical sales by means

of tickets or pieces of paper, on which intending purchasers

write the price they are willing to pay.

430 Glossary.

Tinners. C All Cornish miners.

Tin Stuff. C The name by which tin ore is known in ComwalL

Titanic Acid. A combination of the rare metal titanium (a simple element allied to tin) with oxygen.

TiTANlFEROUS. Containing titanium, or titanic acid.

TOL. C. The portion of ore paid to the 'bounder.'

Toller. C, An inspector of tin bounds, which are usually marked by holes dug in the ground.

TOMALO. C. A big heap of anything. (Welsh, tamefiy a mound.)

Ton of Firewood. Aus. An average of 50 cubic feet of wood.

Topaz. One of the precious stones. Chemical composition, silica 35*52, alumina 53*33, and fluorine 17*49 " 108*33. Colourless, but sometimes tinged pale green, yellow, red, blue, by the presence of other substances.

TORTA. S. A great heap of silver ready for amalgamation.

Tormentor. Aus. A wooden axle studded with iron spikes and turned round in a trough, for the purpose of puddling auriferous clay.

Tourmaline. A rock substance, in some varieties forming one of the precious stones. Chemical composition very varied and complex, its base being about 40 silica, with 8 boracic acid, and varying proportions of alumina, phosphoric acid, manganese, iron, lime, potash, lithia, lime, and soda.

ToziNG, or Tossing. Shaking or tossing the wet tin in a kieve or vat ; the final operation in the dressing of tin ore, in which, by knocking the sides of the vat, the heavy tin ore sinks to the bottom, leaving the refuse on the top.

Trace. To follow the lode on the surfjaice, and to lay it open by long pits.

Trachyte. A variety of felspathic rock, which breaks with a rough surface. It usually contains crystals of hornblende, mica, or felspar.

Trappean. a name given to felspathic rocks, including basalt, dolerite, diorite, greenstone, felstone, porphyry, and the like, from the step or stair-like nature of their escarpments or outcrops. German, treppe a. staircase, or flight of steps.

Treloobing. C, Stirring the looks' or slime tin in water, so that the lighter mud may run off.

Tribute. A sum payable to the original adventurers by miners who take a portion of a mine to work ' on tribute,' the stuff got being their own when the tribute is paid.

Glossary. 43 1

Troiu C a miners' feast or merry-makmg.

Tucker. Aus. Work by which a man can hardly live.

Tucker Ground. Aus, Poor ore gromid.

Tufa. A light soft rock, deposited from water containing carbonate of lime and often found near the base of limestone rocks.

TuRNHOUSE. C The point where the miner turn sfrom a cross cut along the course of a lode.

Tut. C Tut work, dead-work, working in barren ground ; work not yielding profit ; tut-bargain wofk, work taken at a fixed lump price.

Tye, C. I. a small frame like a strake. 2. An adit or drain.

Van. Dressing a small quantity of ore by hand for the purpose

of testing the quality of the ore and the capacity of die lode

beforehand. Vara. S. A Spanish yard 33 English inches. Vale, or Val. The plae where the reserve of tin ore is placed to

dry before it is put into the smelting furnace. Velado. S. a mine watchman. Vena, or Veta 5*. A lode or vein, as Vena Madre, the Mother

Vein. Vesicular. Containing numerous vesicles or cavities. Vinewed, or Vinney. Copper ore, with a green efflorescence like

verdigris. Vitreous. Of a flinty or glassy nature. Voladoras. S. The grinding stones of one kind of arrastres. VUGH. C A hollow or cavity in the rock.

Wall of a lode. The boundaries of a lode. See Hanging side'

and ' Heading side.' Wash Dirt. Am, &*Aus. The name given to the beds of drift

in which the gold is usually found. Washing Off. (Washing up, Am, Aus,) The periodical final

cleaning out of all the gutters and appliances used in alluvial

and rock gold mining. Water Barrel. A barrel used to wind water at a mine. Water Boss. Am, &*Aus, The owner or holder of water or

water rights, who sells the same for mining purposes.

432 Glossary.

Water Men. Men employed in the extraction of water, especially

with the rag and chain pump. Weeldon. Name given in the Forest of Dean to old ironstone

workings. Whele, Wheal, Huel. C. A mine.

Whim. A drum with a vertical axis (see fig. 6), with rope attached, worked by a horse, for winding purposes from shallow

depths. Whip and Derry. A bucket or kibble drawn up a shaft by means

of a rope over a pulley, the rope being attached to a horse

who moves straight forward. Winds or Winze. A small shaft sunk from one level to another

underground. Work. G. werk, A mine. Working Barrel of a pump. The part the clack valve or*

bucket works in. Working Big. When the lode in working admits of a space 2(

feet wide, so that the miner need not break down any of the

adjacent rock. Wythern. W. Vein, or lode.

Zigher. C, a small stream of water running slowly undeiground. Zone. Name given to a belt or band of strata, and to groups of

strala distinguished by similarity of organic remains or mineral

chanu:teristics.

Index

Apr

A FRICA, copper deposits of, izg ;

gold drifts of, 77

Algeria, copper mines of, 119; iron ores of, S161 ; lead mines, ; zinc mines of, 244

Altai Mountains, silver mines of, 83

America, Central, gold in, 55

America, N.E., bismuth in, 983 ; copper deposits of, 148 ; gold of, 45 ; lead, 23 ; nickel, 287 ; platinum, 288 ; silver, 94 ; zinc ores of, 247

America, N.W., copper deposits of, 155 ; iridium in, 289 ; gold of, 48 ;

' laid, 235 ; mercury, 282 ; iron ores of. 275 ; silver, 94 ; tellurium, 290 ; zinc ores of, 247

America, S., copper deposits of, 158 ; gold, 55-62 ; mercury, 284 ; nickel, 288 ; paTladinm, 285 ; platinum, 288 ; silver, 108-10

Andes, the, 7, zio

Anglesea, copper mines of, 138

Appalachian Mountains, 7, 45

Arizona, silver ores of, 107

Australasia, copper mines of, copper production of, 159 ; deposits of, 63 ; iron ores of, 279

Austro-Hungary, bismuth ores of, 285 ; copper, i2z ; gold, 38 ; iron, 25 ; lui, z8 ; mercury, 282 ; nickel, 286 ; alver, 83, 85 ; tellurium, 90 ; zinc, 242

BALLARAT, gold deposits of, 73 Beds of mineral, 35 Bel£[iimi, iron ores of, 29 ; lead mines of, 199 ; zinc deposits of, 244 Bismuth, ores of, 28 ; m Cornwall, 285 ; the EnbiigCi Germany,

159: firold

goi

Chi

285 ; Schneeberg, Austria, 285 ;

South Carolina, 286 ; Tasmania, 286 Bohemia, silver mines of, 85 Bolivia, silver mines of, zio Bonanzas, 29 Boring by hand, 32Z ; by machinery,

3az Boring machines, air or steam, 321 ;

hand power, ditto, 328 Borneo, platinum of, 389 Branches in veins, Z2 Brazil, gold mines of, 55 ; nickel in.

288 ; palladium in, 990 Buddies and huddling, 369

CALIFORNIA, alluvial gold mining in, 48 ; discovery of gold in, 48 ; gold production of, 49 ; geological structure of, 52 ; quartz gold mining, 54 ; silver production

Canada, copper deposits of, Z55 ;

gold, 47 ; iron, 27Z ; lead, 233 ;

nickel, 287 Cardiganshire, copper ores of, Z44 ;

lead ditto, 21 z ; lodes of, 210 ;

mines and mining in, 207 ; zinc

production of, 246 Carnarvonshire, copper ores of, Z38,

Z44 ; lead mines of. 2Z3 Carolinas, N. and S.. bismuth in,

286 ; gold mining in, 46 ; pUtinum

in, 289 Carpathian Mountains, 6 Cheshire, cupreous sandslooes of, Z36 Chili, copper deposits of. Z58 ; mining

districts of, ZIO ; silver mines of, 1 1 1 China, gold deposits of, 79 ; mercurial deposits of, 28a

F F

Index,

Cle

Cleveland iron ores, deposits of, 369

Coal-measures, iron ores of, 267

Colorado, copper deposits of, 156 ; sold productions of, 49 ; lead carbonate deposits of, 238 ; silver production of, 95

-Columbia, British, gold deposits of, 49

Comstock lode, 99

Connecticut, copper deposits of, 147 ; nickel deposits of, 287

Contact deposits, 26, 30

Copper mining, 388

Copper, ores 01, 114; Africa, S., 118; Algiers, 119; America, 147; Anglesea, 138 ; Australasia, 159 ; Austria, 121 ; Britain, 125 ; Canada, 154 ; Cardiganshire, 145 ; Carnarvonshire, 138, 144 ; Cheshire, 136 ; Cornwall, 131 ; Cuba, 157 ; Cumberland, T45 ; Derbyshire, 138 ; France, 123 ; Germany, 121 ; Ireland, 145 ; Italy, 120 ; Japan, 160 ; Lake Superior, 149 ; Maryland, 147 ; Merionethshire, 144 ; Mississippi Valley, 150 ; Russia, 118 ; Newfoundland, 147 ; Norway, 122 ; Shropshire, 136 ; Spain, 120 ; Staffordshire, 138 ; Tennessee, 149 ; Sweden, 123 ; Venezuela, 158

Cornwall bismuth in, 285 ; copper deposits of, 135 ; epochs of disturbance in, 129 ; geological structure of, 127 ; great flat lode of, Z73 ; history of copper mining in, IQ4 ; of tin mining, 171 ; iron ores of, 262 ; lead ditto, 215 ; lodes of, 131 ; mining districts of, 129 ; silver in, 93 ; tin mines of, 172 ; zinc production of, 246

Crystallography, 3

Cuba, copper in, 157

Cumberland, copper mines of, 145 ; lead mines of, 2x8

DEAN, FOREST OF. iron ores of, 263 Denbighshire, lead mines of, 230 Derbyshire, copper mines of, 138;

lead mines of, 228 Devon, iron ores of, 263 ; lead mines

of. 2X8 Devonian strata, order of, 218 Disseminated ores. 30 Dolgelly. gold mines of, 40 Drainage of mines, 339

Gol

Durham, lead mines of, 218

Duty of piunping engines, 341, 344

ELECTRICITY affecting the deposition of metallic ores, 23; use in mining, 337

Elements, simple, chief distinctions of, 2 ; list of names of, i ; scale of hardness of, 2 ; shapes of, 3 ; specific gravity of, 2 ; variations of, i

Erzgebirge, geological structure of, 86 ; Ities of, 87

Eiqplosives used in mining, 331

FISSURES of displacement, zo ; simple, 8

Flats, ore, 27, 223, 231, 236

Flintshire, lead mines of, 230 ; limestone of, 230 ; nickeliferous iron ore of, 287 ; geological structure of, 9 ; zinc production, 246

France, copper ores of, 123 ; gold in, 39 ; iron ores of, 259 ; lead, 198 ; silver, 89 ; tin, 170

Freiburg, metalliferous lodes of, 87

GERMANY, copper deposits of, 121 ; iron ores of, 256 ; lead mines of, 192 ; mercurial deposits of, 283 ; nickel in, 286 ; silver mines of, 89; tin deposits of, X67; zinc ditto, 243

Gold, analyses of, 33, 62 ; characterisation and mode of occurrence, 33 ; driftal gold, 33 ; formation of nuggets of, 34

Gold, deposits of, in Africa, 76 ; America, N.E., 45 : America, N.W., 48 ; America, S. 55; Aruba Island. 79 ; Austro-Hungary, 38 ; British Columbia, 51 ; British Isles. 40 ; Brazil,, 55 ; California, 48 ; Cardiganshire, 40 ; Central Europe, 38 ; China, 79 ; France, 39 ; Georgia. 45 ; India, 79 ; Ireland, 43 ; Italy, 39 ; Lake Superior, 47 ; Merionethshire, 40 ; New England States, 45 ; New South Wales, 63 ; New Zealand, 75 ; Nova Scotia, 47 ; Persia, 77 ; Philippine Islands, 79 ; Queensland, 64 ; Rhine, 39 ; Scotland, 43 ; Spain, 39 ; Tasmania, 64 ; Venezuela, 55 ; Victoria, 64

Index,

Gol

Gold mining, hydraulic. 375, 383

Gold mining, quartz, 383

Gold reefs, structure of, 66-69

Gossan, 15

Gravity, specific, a, 36

Great &itain, bismuth m, 385 ; copper

deposits of, 125 ; gold ditto, 40 ;

iron ditto, 36a ; lead ditto, soo ;

nickd, 387 ; platinum, 389 ; silver,

93 ; tin, 171 ; zinc, 345 Gtcat flat lode of Cornwall, 173 Great Ormes Head, copper deposits

of. 138

HANOVER, lead mines of, 193 ; silver in, 89 Hartz Mountains, mines of, 193 ;

structure of, 193 Heat of mines, 3x9 Hydraulic gold mining, 375

ILLINOIS, lead mines of, 334 India, gold deposits of, 79 ; iron ores of, 354

Iowa, lead mines of, 334

Ireland, copper deposits of, 145 ; gold ditto. 44 ; iion ditto, 363-74 ! ditto, 333

Iridium, 389

Iron ores, 350 ; in Algeria, 361 ; Australasia, 379 ; Austria, 355 ; Belgium, 39 ; Canada, 275; Cleveland (Yorkshire), 369 ; Coal-measures, 367 ; Connecticut, 377 ; Cornwall, 362 ; Ctunberland, 366 ; Dean Forest, 263 ; Devon, 263 ; France, 359; Germany, 356: India, 354; Ireland, 374 ; LAncashire, 366 ; Lake Superior, 378 ; Lincolnshire, 373 ; Michigan, 378 ; Missouri, 377 ; Nassau, 356 ; Northamptonshire, 373 ; Norway, 356 ; Russia, 355 ; Spain, 360 ; Syreden, 356

Ironstone mining, 395

Irregular mineral deposits 39

Isre (France), lodes of, 89

Isle ot Man, lead mines of, 3x5 ; silver production of, 93 ; zinc production of, 346

Italy, copper deposits of, lai ; gold ditto. 39

JAPAN, copper mines of, 163 Jiggers and jigging, 363

Met

KONGSBERG. silver lahlbands of, 91

LADDERS, 308 Lake Superior, copper ron of, X50 ; gold in lodes of, 47 ; iron ores of, 378 Lead mining, particulars of costs of,

39a Lead ores, 189 ; in Algeria, 198 ;

Austro-Hungary, 191 ; Belgium. 199; Canada, 333; Cardiganshire. 307; Carnarvonshire, 313; Colorado, 338 ; Cornwall, 3x5 ; Cumberland, 3x8 ; Denbighshire, 330 ; Derbyshire, 338 ; Devonshire, 317 ; Durham, 318 ; Flintshire, 330 ; France, 198 ; Germany — Erzgebirs, 85 ; Hartz, 193 ; Nassau, 194 ; Silesia, 193 ; Illmois, 334 ; Iowa, 334 ; Ireland, 333 ; Isle of Man, 3x5 ; Missouri, 337 ; Montgomeryshire, 303 ; New England States, 333 ; New York, 334 ; Northumberland, 3x8 ; Spain, 195 ; Westmoreland, 3x8 ; Wisconsin, 334 ; Yorkshire, 333

Levels, adit, qxx ; ordinary working. 3x3 ; cost ca, 313-9X ; timbering of, 311, 31a, 3x4

Limestone, strata of, Denbighshire, 330 ; Flintshire, 330 ; Northumber' land, 3x8 ; Yorkshire, 325

Linares, mining district of, 90, 196

T Jncolnshire, iron ores of, 373

Lizard Point, tin ore of, 138

Uangynog, structure of mining district of, 304

Uanrwst, ditto, ditto, 2x3

Llanymynech Hill, old mines of. 137

Lodes, 8 ; classification of, ; earthy constituents of. 15; metallic contents of. 17 ; varieties of, 15. 16

MAN ENGINES, 309 Mercury, ores of, a6x ; in Austria, 383 ; California, 383 ; China. 383 ; Germany, 383 ; Italy, 383 ; Mexico, 384 ; New Grenada. 384 ; Peru. 384 ; Spain, a8a ; Sweden, 383

Merionetlishire, copper deposits of. X44 ; gold ditto, 40

Metallic ores, classification of the deposits of, 8 ; deposition of, affected

Index.

Met

by electricity. 23 ; by condenaatioii, 21 ; infiltration, ao ; sublimation, 22 ; stratifuraphical position of, 26

Metals, chief modes of occurrence of, 4 ; noble. 4 ; useful, 4

Mexico, mercurial deposits of, 284; silver mines of, 107

Michigan, iron ores of, 278

Mine explorers, 297

Mines, chief mines and deposits referred to— AlderleyEdge, 136; Altenberg, 167 ; Besohi, 162 ; Blinman, I2Z ; Bultron, Z2z ; Burghley Park,

, 273 ; Surra Burnt, 160 ; Calumet and Heda, 155 ; ChanaradUo, iii ; Cliff (America), 153 ; Cligga, 179 ; Comstock, of the, 95 ; Condurrow, 175 ; Coniston, 145 ; Comb Martin, 2x8 ; Danemora, 257 ; Dolcoath, 132 ; Dolly Hide, 148 ; Eardiston, 136 ; Ecton, 138; Emma, 103; Foxdale, 92 ; Geyer, 168 ; Congo Soco, of,

f7 ; Great Laxey, 92 ; Haytor, 263 ; lerods Foot, 2x5 ; Homachos, 91 ; Little Aimie, 54 ; Morfa Ddu, 143 ; Neugluck, IX ; New Llangynog, 203 ; New Quebreda, 158 ; Norm Hendre, 231 ; Nouvelle Montague, 109 ; Old Ballymurtagh, 146 ; Old Ilewas, x8o ; Old Park, 265 ; Old Pencraig, 214 ; Old Wheal Agnes, 12 ; Oravicsa, of, 36 ; Ore Hill, 277 ; Ovoca, of, 145 ; Paxys Mountain, 138 ; Pasco, X08 ; Pontgibaud, 198 ; Rammelsbeig, X93 ; Rio Tinto, 121; Roman gravels, 201 ; Ruby Hill, of, xoi ; Simon Judas, 85 ; Snailbeach, 203; Snowball, 162; Sormanosk, 36 ; St. John del Rey, 59 ; Van, 206 ; VieUe Montague, 244 ; Vigra and Clogau, 41 ; West Chiverton, 215; Wheal Basset, West, 174; Wheal Lovdl, East, 177 ; Wheal Mary Ann, 2x7 ; Wheal Uny, 174 ; Zinwald, 166 Mines. (Uscovcry of, 296 ; drainage of, 339 ; heat of, 3x9 ; management of, 399 ; purchase and sale of, 40X ; timber used in, 3x8 ; ventilation of, 3x9 ; working of, 303 M*nin, electricity used in, 337 ; explosives used in, 331 ; particulars of work and cost relating to copper, 388 ; gold hydraulic. 383 ; gold quartz, 382 ; iron, 395 ; lead, 392 ; silver, 384 ; tin. 390 ; zinc, 393

Par

Missouri, iron ores of, 377

MountainsAndes, 7, xio ; Appalachian, 7, 45 ; Australian, 7 ; Carpathian, 6 ; Erzgebirge, 85 ; Harti, 6, 192 ; Himalayas, 79 ; Pennine, 6, 217 ; Rocky, 48 ; Ural, 6, 35, 118 ; Wahsatch, IQ3

NASSAU, iron deposits of, 256; lead ditto, X94 ; silver in, 89 Network of veins, 30 Nevada, silver mines of, 100 New Brunswick, gold of, 47 New Caledonia, nickel ores of, 288 New England States, 234 New Grenada, mercurial deposits oC

New South Wales, gold deposits oC

47 ; tin deposits of, X85 New York, 234

New Zealand, gold deposits of, 75 Nickd, ores of, 286 ; in America, 287 ; America, South, 288 ; Austro- Hungaiy, aS6 ; Germany, 286; Great Britain, 287 ; New Caledonia, 288 ; Norway, 287 ; Spain, Northamptonshire, iron ores of, 273 Northumberland, lead mines of, 2x8 Norway, copper mines of, X22 ; iron

ores of, 256 ; nickd ores of, 287 Nova Scotia, gold in, 47 ; iron ores of, 27s

ORES of bismuth. 285 ; copper, 1x4 ; gold, 02 ; iridium, ; 246 ; lead, X87 ; mercury, 28X ; nickd, 286 ; palladium, 290 ;

288 ; silver, 81 ; telurium, 290 ; tin, X64 ; zinc, 24X Ores, dressing of, gold, 372 ; lead, 350; silver, 372; tin, 372; huddling, 369 ; crushing, 35X ; grind-

inST. 354 1 jigging. 33 5 picking and sorting, 350 ; stamping and stamps,

Ores, stratigraphical zones of the

various, 295

PALLADIUM. 990 Particuhirs of mining work and costs, 382 Pairs Mountain copper mine. 138

Index.

Pen

Pennine Chain, the, strncture of, 919 Feru, mercurial deposits of, 284;

silver ditto, 108 Pickini; and sorting of orei, 350 Platinuna, aSS ; ores of, in America,

N., 389 ; America, S., 289 ; Borneo,

289 ; Russia, 989 ; Shropshire, 289 Pumping engines, 340 ; arrangements

of, in a shaft, 346; duty of, 341, 345 Purchase and sale of minei, 40Z

QUEENSLAND, gold deposiU of, 64 ; tm ditto, 184

RHINE, gold washings of, 39 Rocky Mountains, 48 Rothsch5nberg Tunnel, 89 Ruby Hill, mines of, 100 Russia, copper deposits of, 82 ; gold ditto, 36 ; iron, 259 ; platinum, 289 ; silver, 82 ; zinc, 243

SARDINIA, zinc deposits of, 243 Saxony, silver mines of, 85

Scotland, gold deposits of, 43 ; lead mines of, 231

Sjegated masses of ore, 26

Shafts, mine, arrangement of, 301 ; cost of, 387 : ladders in, 308 ; perpendicular, 304 ; sinking of, 308 ; size of, 307 ; slanting. 305

Shropshire, copper deposits of, 137 ; lead mines of, 200; platinum in,

Siena Nevada, geological structure of, 52

Silesia, zinc deposits of, 243

Silver, ores of, 79 ; in America, N.E., 94 : America, N. W., 94 ; America, S.. 108 ; Arizona, 107 ; Austro- Hungary, 83 ; Bohemia, 85 ; Bolivia, zio ; Chili, 1x0 ; Ftance, 89 ; Germany, 85 ; Brmuwick, 2 ; Hanover, 85 ; Nassau, 89 ; Saxony, 85 ; Great Britain; 92 ; Mexico, 107 ; Norway, 91 ; rem, 108 ; Russia, 82 ; Spain, 90

Spain, copper deposits of, 120 ; gold ditto, 39 ; iron, 260 ; lead, 195 ; mcrcuiT, 282 ; silver, 90

Staffordshire, copper deposits of, 138

Stockwerk, Z2 ; of Altenbei, 167 ; Cligga, 179; Geyer, z68

Wah

Stopes, OTorhind, 315; underhand.

Strata, affecting earthy contents ol lodes, 14; ditto metallic contents, 15 ; ditto width of lodes, 14 ; das sSoation of, 5 Stratified minenil deposits, 25 Stream tin of Banca, 165 ; Cornwall,

Summary of facts relating to the conditions under which is found copper, 163 ; gold, 79 ; iron, 280 ; lead, 239 ; mercury, 284 ; nickel, 288 ; silver. 1x3 ; tin, x88 ; zinc, 218 Sutters Mill, discovery or gold at, 49 Swaledale, mining district of. 226 Sweden, copper deposits of, 122 ; iron, ores of, 256 ; mercurial deposits of,

TASMANIA, bismuth in, 286; gold production of, 64 ; tin deposits of, 187

Tellurium, 290; in America, N.W., 990 ; Austro-Hungary, 290 ; Transylvania, 290

Tennessee, copper ores of, 149

Timber used m mines, 318

Timbering in mines, methods of, 308, 311, 3x2, 3x4

Tin mining, particulars of cost of, 390

Tin ores, X64 ; of Banca, 165 ; Bmeton, X65 ; Bohemia, x66 ; Bolivia, 184 ; Cornwall, 171 ; France, 170 ; Malay Peninsula, X65 ; New South Wales, 185 ; Queensland, X84 ; Saxony, X67 ; Sweden, X70 ; Tasmania, 187 ; Victoria, 187

UNITED STATES OF AMERI- CA, gold production of, 54 Ural Mountains, 6, 35, x8, 289 Utah, geological structure 01, 104 ; silver deposits of, X03

T7EINS, gash, 11 ; network of, 30 V Venezuela, copper deposits of,

158 ; Jfold in, Ventilation of mmes, 319 Victoria, geological structure of, 65 ;

gold deposits of, 65 ; tin deposits

of, 187

Wahsatch Mountains*

Index.

Wal

Wales, North, copper deposits of,

137 i ditto, 41 ; lead ditto, 903 Wales, South, copper in, 145 ; gold

in, 41 ; lead in, 907 Water-wheels, use of, 340 Wicklow, copper in, 145 ; gold, 44 ;

lead, 332 Windmills used in mining, 347 Winzes, 308 Wisconsin, copper deposits of, 150;

lead mines oif, 234

Zin

YORKSHIRE, iron ores of, 069; lead mines of, 223

ZINC MINING, pardculais of work and costs, 39 Zinc ores, 241 ; in Algeria, 244 ; America, N.E., 247; America, N. W., 948 ; Bdlgium, 244 ; France, 245 ; Great Britain, 245 ; Russia, 243 ; Sardinia, 243 ; Silesia, 243

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Barlow's Strength of Materials, enlarged.

A TREATISE ON THE STRENGTH OF MATERIALS; with Rules for Application in Architecture, the Construction of Suspension Bridges, Railways, &c. By Peter Barlow* F.R.S. A New Edition, resist d by his Sons. P. W. Barlow, F.R.S., and W. H. Barlow, F.R.S. ; to which are added, Experiments by Hodgkinson, Fairbaikn, and Kirkaldy ; and Formule for Calculating Girders, &c. Arranged and Edited by W. Humbrr, A-M. Inst. C.E. Demy 8vo, 400 pp., with 19 large Plates and numerous Woodcuts, x8s. cloth.

" Valuable alike to the student, tyro, and the experienced practitioner it wHI aHays rank in future as it has hitherto done, as the standard treatise on that panlcular subject t "--J,ftjuetr.

" A book which no engineer of any kind can afford to be 'mxhovil."-C*Uterjt Guatatait.

There is no greater authority tlan Barlow."— AVntf. The Imok is worthy of the highest commendation. and of an honourable pLice In the library of every engineer."— A/</nf yoummi,

"... Ai scientific work ot the fir cUi% It deserves a foremost f" ht 'wok'h-li'

4 Crosby Lockwood Co: S Catalogub

Survey JPractice.

AID TO SURVEY PRACTICE, for Refirtna in Surveying, LeviU lingt Sitting-out and in Routt Surveys of TravMtrs by Land and Sea, With Tablet, lUustrations, and Records. By Lows D'A. Jackson, A.M.I.C.E., Author of " Hydraulic Manual," " Modern Metrology, ' ' ac. Large crown 8vo, i.6i. cloth.

Mr. Jadcson hu prodoced a raliubla vaJg-mecum for the surreyor. We can raconunend this book as containing an admirable supplement to the teaching of the accompluhed surreyor."—

" cannot racooiniend to the student who knows something of the mathematical principles of the subject a better course than to fortify his practice in the Mid under a competent surreyor with a study of Mr. Jackson's u&eful mwDtuL"—BuiltHfte News.

The author brings to his work a fortunate union of theory and practical experience which, aided by a clear and ludd style of writing, tenders the book a very useful one."— aniiBfr.

A TREATISE ON THE PRINCIPLES AND PRACTICE OF LEVELLING. Showing its Application to purposes of Railway and Civil Eiigineering, in the Construction of Roads: with M r.TBLTOKo's Rules for the same. By Frbdbricx W. Simms, F.G. S., M. Inst. C.B. Seventh Edition, with the addition of Law's Practical Examples for Setting-out Railway Curves, and Tkautwinb's Field Practice of Laying-out Circular Curves. With 7 Plates and numerous Woodcuts, 8vo, 8. 6d. cloth. Trautwimb on Curves, separate, 55.

The test-book on lerdllog In most of our engineering schools and college i.'*~£w,fwef r.

The publishers have rendered a substantial service to the profession, especially to the younger members, by bringing out the present edition of Mr. Sinuns' useful work."— J?|fMMruf'.

PR A CTICAL TUNNELLING. Explaining in detail the Settingout of the works, Shaft-sinkingand Heading-driving, Raneing the Lines and Levelling underground, Sub-£zcavating, Timbering, ana the Construction of the Brickwork of Tunnels, with the amount of Labour required for, and the Cost of, the various portions of Uie work. By Frbdbrick W. Simms, F.G.S., M. Inst C.B. Third Edition, Revised and Extended by D. Kinnrar Clark, M. Inst. C.B. Imp. 8vo, with az Folding Plates and numerous Wood Engravings, 30s. doth. 'The estimation In which Mr. Sfanms* book on tnnndling has been held for over thirty years

cannot be more truly ezpraased than In the words of the late Professor Rankine The best source of information on tne subject of tunnels Is Mr. F. W. Sinuns' work on Practical Tunnelling.' AreMUet.

It has been regarded from die first at a of the subject. Mr. Clarichas added immensely to the value of the book."— £|fwiMr.

" The addltkmal chapters by Mr. Clark, containing as tiiey do Bumarons eimples of modem practice, bring the book well up to date fiyiMMrMtf'.

Statics, Graphic and Analytic,

GRAPHIC AND ANALYTIC STATICS,in Theory and Companion: Their Practical Application to the Treatment of Stresses in Roofs, Solid Girders, Lattice, Bowstrmg and Suspension Bridges, Braced Iron Arches and Piers, and other Frameworks. To which is added a Chapter on Wind Pres< sures. By R. Hudson Graham, C.E. With numerous Examples, many taken from existing Structures. 8vo, 16s, cloth.

" Mr. Graham's book will find place wherever graphic and analytic statics aroused or studied." JiH£tnetr,

"This exhaustive treatise Is admirably adapted for the architect and engineer, and will tend to wean the professloo from a tedious and laboured mode of calculation. To prove the accuracy of the BTaphicsl demonstrations, the author compares them with the analytic formulae given by Ranyii£r-'BnildlMr News.

work is excellent from a practical p< of view, and has evidently been prepared with much care. The directions for working are ample, and are illustrated by an abundance of wellselected examples. It is an excellent text-book for the practical draughtsman."— yfMMrjrMr.

Strains, FormtUoR and IHagramsfor Calculation of.

A HANDY BOOK FOR THE CALCULATION OF STRAINS IN GIRDBSS AND SIMILAR STRUCTURBSt AND THEIR STRENGTH. Consisting of Formulss and Corresponding Diagrams, with numerous details for Practical Application, &c. Bv William Humbbr, A-M. Inst. CB.. &c. Third Edition. Crown 8vo, nearly 100 Woodcuts and 3 Plates, 7$. 6d, cloth. The fiMmnlae are neatly expressed, and the diagtama good."—AtMetunim.

We heartOy commend this really hantfy book to our engineer and architect readaa."— J?Mh UthMecMtmie,

Hydraulic ToMes.

HYDRAULIC TABLES, CO-EFFICIENTS, and FORMULAS for finding the Discharge of Water from Orifices, Notches, Weirs, Pipes, and Rivers. With New FormolaB, Tables and General Information on Rainfall, Catchment- Basins, Drainage, Sewerage, Water Supply for Towns and Mill Power. B7 JoHM Nevillb, Civil Engmeer, M.R.I.A. Third Edition, carefully revised, with considerable Additions. Numerous Illustrations. Crown 8vo, Z4J. doth.

Alike valnable to stndeutB and anglnMn In practice ; Its ittidjr will prerent the annoyance of ▼oldabJe foilurei and angst them to select the readiest means of successfuUy canylag out any given work connected with hydraulic engitMoriag.''—JHftiH£3*urtiai.

" It is, of all Enfflish books on the subject, the one nearest to completion. . . . From the Kood arrangement of the matter, the dear eapunations, and abundance of formabe, the careftiOy calculated tables, and, above all, the thorough acquaintance with both theory and construction, which is displayed from 6rst to laist, the book will be found to be an acquisition.— rckntec/.

River Engineering.

RIVER BARS : The Causes of their Formation, and their Treatment by Induced Tidal Scour. " With a Description of the Sncoessfnl Reduction by this Method of the Bar at Dublin. By I. J. Mann, Assist. Bng. to the Dublin Port and Docks Board. Royal 8vo, 7s. 6d. cloth.

" AVe recommend all Interested in harbor works— and, indeed, those ooooemed In the ImproTement of rlrers generally— to read Mr. Mann's interesting work on the treatment of rirer bars.' — Engineer,

" The author's discussion on waTO-action, currents, and scour Is Intelligent and Interesting. . . a most valuable contribution to the history of this branch of engineering.*'— fytfiwMriii and MiHing ypurnal,

HYDRA ULIC MANUAL. Consistiog of Working Tables and Explanatory Text. Intended as a Guide in Hydraulic Calculations and Field Operations. By Lowis D'A. Jackson. Fourth Edition, Rewritten and Enlarged. Large crown Svo, x6f . cloth.

The author has had a wide experience In hydraulic engineering, both In South America and In India, and has been a careful observer of the facts which nave come under his notice, as wcU as a painstaking collector and critic of the results of the experiments of othen ; and from the great mass of material at his command he has constructed a manual which may be accepted as a trustworthy guide to this branch of the engineer's profrssioii. We can heartDy recommend this volume to all who desira to be acquainted with the latest derbopment of this unpoctant sobJecL"- Jinrififtt'ifte''

" The most nscftil fate of thb work Is Its freedom from what to superannuated, and its thorough adoption of recent experiments; the text is, la fact, la great part a short account of the great modern experiments."— yvat/terv.

Tramways and their Working.

TRAMWAYS: THEIR CONSTRUCTION AND WORKING. Embracing a Comprehensive History of the System : with an exhaustive Analysis of the various Modes of Traction, including Horse-Power, Steam, Heated Water, and Compressed Air ; a Description otthe Varieties of Rolling Stock: and ample Details of Cost and Wbricing Expenses: the Progress recently made in Tramway Construction, &c. Ac. By D. Kinkxak Clark, M. Inst. C.E. With over aoo Wood Engravings, and 23 Folding Plates. Two Vols., large crown Svo, 301. cloth. " An interested In tramways must rate to It, as all eaUway engin— ts have turned totbeanUwrli

work KaOway Machinery.'"— £ir*Mfr.

" An exhaustive and practical work on tramways. In which the hbtoiy of dib Uod of locomo>

tton. and a deaaription and ooet of the varloua modes of laying tramways, are to be found. '—

Builtlitijr Neaa.

" The best form of rails, the best mode of construction, and the best mechanical appHaaoaa

are so fairly indicated In the work under review that any engineer about to construct a tramway

will be maflrfl at once to obtain the practical information which wil be of moat lervke to him."—

Oblique Arches.

A PRACTICAL TREATISE ON THE CONSTRUCTION OF OBLIQUE ARCHES, By John Hart. Third Edition, with Plates. Imperial Bvo, 85. cloth.

Strength of Oirders.

GRAPHIC TABLE FOR FACILFTATING THE COMPUTA- TIOS OP THB WEIGHTS OP WROUGHT IRON AND STEEL GIRDERS, &c., for Parliamentary and other Estimates. By J. H. Watson BuoK, M. Inst. CE. On a Sheet, 9s.6d.

Crosby Lockwood &- Cos Catalogue.

Tables for Setting-out Curves.

TABLES OF TANGENTIAL ANGLES AND MULTIPLES for SettiHf['OtU Curves from s to 200 Radius. Bv Alexander Beazkley, M. Inst. C.E. Third Edition. Printed on 48 Cards, and sold in a cloth box, waistcoat-pocket size, 3s. 6d.

" Rch Ubie is printed on a small card, kich, bcini; placed on the theodolite, cares the hands free to uunipulate tne Instrument— no null .-idvants as thcnpUhty of work.'— tngiturr

" Very liandy ; a man may know tttat all his day's work must fall on two of these cards, which fc puts into his own and leaves the rest behind."— ItAtuettm.

Engineering FieUUvork,

THE PRACTICE OF ENGINEERING FIELD WORK, aHJied to fand and Hydraulic, Hydrographic, and Submarine Surveying and LeviUing. Second Edition, Revised, with considerable Additions, and a Supplement on Waterworks, Sewers, Sewage, and Irrigation. By W. Davis Haskoll, C.£> Numerous Folding Plates. In One Volume, demy 8vo, £1 5s. cloth.

LiCwge Tunnel Shafts.

THE CONSTRUCTION OF LARGE TUNNEL SHAFTS: A Practical and Theoretical Essay. By J. H. Watson Buck, M. Inst. C.E., Resident Engineer, London and North- Western Railway. Illustrated with Folding Plates, royal 8vo, las. cloth.

" Many of the methods given are of extreme practical value to the mason ; and the observations on tlie form of ardi. the rules for ordering the stone, and the construction of the templates will be found of considerable use. We commend the book to the engineering profession."— i7i7</rM AVw/.

" WiO be regarded by civil cneineers as of the utmost Talae, and calculated to save much time and obviate many mistakes."— CW/(£rr> Cnantiati,

Field'Book ftyr Etigineers.

THE ENGINEER'S, MINING SURVEYOR'S, AND CON- TRA C TOR 'S FIELD-BOOK. Consisting of a Series of Tables, with Rules. Explanations of Systems, and use of Theodolite for Traverse Surveying and Plotting the Work with minute accuracy by means of Straight Edge and Set Square only ; Levelling with the Theodolite, Casting-out and Reducing Levels to Datum, and Plotting Sections in the ordinary manner ; Curves with the Theodolite by Tangential Angles and Multiples, with Right and Left-hand Readings of the Instrument: Setting-out Curves without Theodolite, on the System of Tangential Angles by sets of Tangents and Offsets : and Earthwork Tables to 80 feet deep, calculated for every 6 inches in depth. By W. Davis Haskoll, C.E. With numerous Woodcuts. Fourth Eaition, Enlarged. Crown 8vo, 125. cloth.

*'The book Is very handy, and the author might have added that the separate tables of sines and tangents to every minute will make it useful for many other purposes, the genus:te traverMS tables existing all the w.vM."—AtA€attm.

"E\-ery person engaged in engineering field operations will estimate the Importance of such a work and the amount of valuable tunc which will be saved by reference to a set of reliable tables prepared with the accuracy and fulness of those given ui this volume."— A'ak/w News.

Earthwork Measurement and CcUculation of,

I A MANUAL ON EARTHWORK. By Alex. J. S. Graham, I C.E. With numerous Diagrams. x8mo, zs. 6d. cloth.

A great amount of practical information, very admirably arranged, and available for routrh evlliitnics, ns well Ab for the tuoro exact calculations required in the engineer's and contractors offi CCS, "— /f rti€tn.

Strains.

THE STRAINS ON STRUCTURES OF IRONWORK; with Practical Remarks on Iron Construction. By F. W. Shsilds, M. Inst. C.E. Second Edition, with 5 Plates. Royal 8vo, 5s. cloth. The student cannot find a better little book on this subject"— fnfi'iMvr.

Strength of Cast Iron, etc.

A PRACTICAL ESSAY ON THE STRENGTH OF CAST IRON AND OTHER METALS. By Thomas Tredoold, C.E. Fifth Edition, inclading Hodokiksom's Bxperiraental Researches. 8vo, las. cloth.

Mechanics 6- Mechanical Engineering. 7

Mechanics & Mechanical Engineering.

Mechanic's Workshop Companion,

THE OPERATIVE MECHANICS WORKSHOP COM PANION, AND SCIENTIFIC GENTLEMAN'S PRACTICAL ASSIST- ANT, Comprisiiif) a great variety of the most useful Ruls io Mechanical Science ; with numerous Tables of Practical Data and Calculated Results. By W. Templstom, Author of "The Engineer's Practical Assistant." Thirteenth Edition. With Tables for Operative Smiths, Millwrights, Engineers, &c., and Useful and Practical Rules in Hydraulics and Hydrodynamics, a variety of Experimental Results, and an extensive Table of Powers and Roots, xz Plates, xamo, 5s. bound.

"Asa text-book of refsre&ce, in which mechanical and commercial demands aie Judiciously met, 'Tcmpleton's Companion' stands A/anssine.

" It has met with snreat success in the engineering workshop, as we can testify ; and there are a STcat many men who, in a gmat mcoiiure, owe their rise iu life to this little -ifiiiA/i a" A'eHfs.

Engineer's and Machinist's Assistant.

THE ENGINEER'S, MILLWRIGHT'S, and MACHINIST'S PRACTICAL ASSISTANT, Comprising a collection of Useful Tables, Rules and Data. Codipiled and Arranged, with Original Matter, by William Tbmpleton. Seventh Edition. Carefully revised, with Additions. x8mo, 25. 6J. cloth. [Jmt puhliihed.

" With the utmost ccmfidence wa commend this book to the attention of our renders."—

MechanUs Magauint,

"A more suitable present to an apprentice to any of the mechanical trades could not possibly

Mechanics.

THE HANDBOOK OF MECHANICS, ByDiONYSiusLARDNER, D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. New Edition, Edited and considerably Enlarged by Benjamin Loewy, F.R.A.S., &c. 378 Illustrations, post 8vo, 6s. cloth.

" The explanations throufout are studiously popular, and care has been taken to show the application or the rarious branches of physics to the industrial arts, and to the practical btisiness of

Turning.

LATHE-WORK : A Practical Treatise on the Tools, Appliances, and Processes employed in the Art of Turning. By Paul N. Hasluck. Second Edition, thoroughly Revised, with a New Chapter on the Screw* cutting Lathe. Crown 8vo, 55. cloth.

" Written by a man who knows, not only how work ought to be done, but who also knows how to do and how to coUTey his knowlcdfe to others. To all turners this book would be valuable.*— JittgiMeeriner,

' We can safely recommend the work to younir engineers. To the amateur it will simply bo invaluable. To the student it will convey a great deal of use Ail information."—

"A compact; soccinct; and handy guide to Iathework did not exist in our language until Mr. Hasluck, the publication of this treatise, gave the turner a true vatfe-/nfcutn."-'j/auM Decoratci;

Metal Turning.

THE METAL TURNER'S HANDBOOK, By Paul N. Hasluck. With over xoo Cuts. Crown 8vo, is. cloth.

Iron and Steel.

IRON AND STEEL '' : A Work for the Forge, Foundry, Factory y and Office, Containing ready, useful, and trustworthy Information for Ironmasters and their Stock-takers; Managers of Bar, Rail. PUite, and Sheet Rolling Mills: Iron and Metal Founders; Iron Ship and Bridge Builders; Mechcal, Mining, and Consulting Engineers ; Architects, Contractors, Builders, and Professional Draughtsmen. By Charles Hoarb, Author of " The Shde Rule," &c. Eighth Edition, Revised throughout and considerably Enlarged. With folding Scales of "Foreign Measures compared with the Ensn Foot.*' and " Fixed Scales of Squares, Cubes, ana Roots, Areas, Decimal Equvalenta, &c." Oblong same, leather, elastic band, 6s. "For comprehensiveness the book has not its equal."— /nm.

" One of the best of the pocket books, and a useful companion in other branches of work than iron and steeL"— fvirA Mechanic,

g CROSBY LOCKWOOD S- CO.- S CATALOgOE.

Stone-tvorkinff Machinerff.

STONE-WORKING MACHINERY, and Iki Rapid and Ecamimi. cat CiMviniim of Sfcnu. With Hint! on Ibe AmuigeiiigDl uid MuhhidsdI o[ SIODB WorkL fifM. PoviiBiLi. M.I.M.B.,A.a.I.CE. Witb nuniarDiii Illoilnlioni. Lugs erom Sro, gi. clolb.

Engineer'B Reference Book.

THE WORKS' MANAGERS HANDBOOK OF MODERN KULES. TABLES, AND DATA. For F-ngiaetn. MUlirrightu, and Boiler HHken; Tool Miken, MichialitL uid Melil Worken; Iran ud Bran

Engineerinff Congtrtiction,

PATTERN-MAKING : A Practieal Treatise,

, Miching Pana, Pumps and Cockt, Ibe MDiildiag of PatleniT'm Loan and Gramuad, &c.. logettaer oilb the melbodi of Bitinutisg the

Reference. Bj a'PoniMAB Paitmii Mami. With opwai of' HDndndaadSevenlrmusuatiam. Crown 9vo, 71. U. clottL (Jiuf uilukf d.

Siitlth'B Tables for SFechanicB, etc.

TABLES. MEMORANDA, AND CALCULATED RESULTS FOR UECHANICS. ENGINEERS, ARCHITECTS, BUILDERS tie Seledsd uid Arruged br Fmhcii Skith, Third £ditiog. Revised asd Enlarged, tjo pp.. waiitCMI-pocket aiu, ii. Cd, limp leather. [Jwl publiiliti'

pwkal CDllail mty bfl loofc

Tfte -Preagiire Steam Engine.

THE HIGH-PRESSURE STEAM-ENGINE : Exbotitam

of ill Comparalivi Mcrili and an Essay loatrdtmIntriiv£iISrilt '— , Bybr.EaNST ALBiii. Tt.nsl.led f™ --

r, P0L11.M. Insi.C.E., Ac. WittaiePliK

ilh Noles, by

he Mp-jrmuu n

'SV-WCAmnlnit.

Steatn BoUers.

A TREATISE ON STEAM BOILERS: Their Strength, Construction and Economical Working, By Robert Wilsom, C.£., late In* spector, Manchester Steam Users* Association. Fifth Edition, xamo, 6s. cloth.

The best treatise that has ever been published on steam \)vials.''—Sft£ttuer, "The author shows himself perfect master of his subject, and we heartily recommend all ea ployinf steam power to possess theaaselves of the work,'— -Jta/and's Ircn Trad* Circular.

BoUer Making.

THE BOILER-MAKER'S READY RECKONER, With Examples of Practical Geometry and Templating, for the Use of Platers, Smiths and Riveters. By John Courtnby, Edited by D. K. Claxx, M.I.C.E. Second Edition, revised, with Additions, xamo, 5s. half-bound. A reliable pride to the working boUeraakert*'— /rm.

" Boiler-makers will readily recognise the Taioe of tills rolume. . . . The tables are clearly Ttrinted, and so arranged that they be referred to with the greatest facility, so that it cannot be : they wiU be generally appreciated and much nseo."— Afto<>v yM

doubted ttut ''

Steam Engine.

TEXT-BOOK ON THE STEAM ENGINE, By T. M. GooDRVz, M.A., Barrister-at-Law, Author of "The Elements of Mechanism," &c. Sixth Edition. With numerous Illustrations. Crown 8vo, 6s. cloth.

"Professor Goodere has glen us a treatise on the steam engine which win bear comparison with anything written Huxley or Maxwell, and we can award it no higher praise."— £>tfmMr.

Steam.

THE SAFE USE OF STEAM. Containing Rules for Uc-

Steam-users. By an Enginbbr. Fifth Edition. Sewed, 6d.

" If steam-users would but learn this little book by heart, boiler exploons would become sen cations by tlieir nrity."— English Mechanic,

Coal and Speed Tables.

A POCKET BOOK OF COAL AND SPEED TABLES, for Engineers and Steam-users. By Nelson Foley, Author of " Boiler Construction." Pocket-size, is, 6d. cloth ; 4s. leather.

Contents :

Table t. Decimals of Tons In .. qrs lbs.— a. Consumption pcrDay perI.H.P. —Table 3. Consumption per Hour per I.H.P. —Table 4. Consumpfiion per Day per sq. ft. grate. — TaUe jc Consumption per Hour per sq. ft. grate.— Table 6. Stowage of Coal and Compoaition.— 7. Knots per Hour <Measured Mile).— Table 8. Knots per Hour (Cloch

and Cumbrac).— Table 9. Decimal EquhnOents of Time.— Table 10. Knots per Hour in ft. per min.- Table ii. Constants Tor I. H. P.— Table n. Decimals of . in lbs.— Table i*. Mea> sures of Weight also Misoellaneoos Results — Combustion, Air required. Stoking, &c.— ' Time and Speed Examples.

Fire Engineering.

FIRES, FIRE-ENGINES, AND FIRE-BRIGADES. With a History of Fire-Engines, their Construction, Use, and Management: Remarks on Fire-Proof Buildings, and the Preservation of Life from Fire; Statistics of the Fire Appliances in English Towns ; Foreign Fire Systems ; Hints on Fire Brigades, &c. dec. By Charles F. T. Youno, CE. With numerous Illustrations, 544 demy 8vo, £1 45. cloth. To such of our readers as are interested In tiie subject of fires and fire apparatus we can most

heartily commend this book. It is really the only English work we now have upon the sulecL"—

Hnitucrinf.

"It displays much evidence of careful research; and Mr. Young has put his facts neatly

together. It is evident enough that his acquaintance with the practical details of the construction of

steam fire engines, old and new. and the conditions with whica it Is necessary they should comply.

IS accurate and fuD."— mutOmct.

Oas Lighting.

COMMON SENSE FOR GAS-USERS : A Catechism of Gas- Lighting for Householders, Gasjiiters, Millowners, A rehiteets, Engineers, etc. By Robert Wilson, C.B., Author of "A Treatise on Steam Boilers." Second Edition. Crown 8vo, sewed, with Folding Plates and Wood Engravings, 25. 6d.

" All gas-ttsers wiD decidedly benefit both fai podiet and comfort If they wiD avaO themtehet of Mr. lson's eowaadM,"— engineering.

io CROSBY LOCkWOOb CO.'S CAtALOcVE.

The Popular Works Of Michael Reynolds.

{Known "The Engine Diuvbr's FitXBifD")i

LOCOMOTIVE-ENGINE DRIVING : A Practical Manual for Engtneers in charge of Locomotivt Engines. By Michael Reynolds, Member of the Societyof Engineers formerly Locomotive Inspector L. B.and S.C. R. Sixth Edition. Including a Key to the Locomotive Engine. With Illustrations and Portrait of Author. Crown 8vo, 4s. 6d. cloth.

"Mr. Reynolds bas supfed a want, and has supplied it wclL We can confidently recommend the not only to the practical driver, but to everyone who tajces an interest in the pcribnnance of locomotive

" Mr. Reynolds has opened a new chapter in the literature of the day. Of the practical utility of Mr. Reynolds's book have to speak in terms nf warm commendation."— ./Arwtfwm.

" Evidently the worit of one who knows his subject thorougWy."— i?tfiiwv Service GoMettt. " Were the cautions and rules given In the book to become part of the every-day working of our enjpne-drivcrs; we misht have fewer dlttressing accidents to

The Engineer f Fireman, and EngineBoy.

THE MODEL LOCOMOTIVE ENGINEER, FIREMAN, and ENGINE-BOY. Comprising a Historical Notice of the Pioneer Locomotive Engines and their Inventors, with a project for the establishment of Certificates of Qualification in the Running Service of Railways. By Michael Reynolds, Author of " Locomotive-Engine Driving." With numerous Illustrations and a fine Portrait of George Stephenson. Crown 8vo, 4s. 6d. cloth.

" From the technical knowledge of the author it will appeal to the railwav man of to-<lay more forcibly than anythiTiE' written by Dr. Smiles. . . . The volume contains information of a technical kuid, and facts that every driver should be fiimiUar wlthu"— i:'jC'A MecAattic.

" We shouM glad to see this book in the possession of everyone ia the kingdom who has eTcr laid, or is to lay, hands on a locomotive engine."— /mm.

" Replete with information and graphic deUil for the railway naiu'—Kai/war Strvice Ca:tette,

Stationarjf Engine Driving.

STATIONARY ENGINE DRIVING : A Practical Manual for Enfincers in charge of Stationary Engines. By Michael Reynolds. Second Edition, Enlarged. With Plates and Woodcuts. Crown 8vo, 4s. 6d. cloth.

"The author Is thoroughly acquainted with his subjects, and his advice en the various points treated is clear and practicaL ... He has produced a manual which is aa exceedingly useful one for the class for whom it is specially intended."— Bnitueriftg'.

" Our author leaves no stone unturned. He is determined that his readers shall not only know something about the stationary engine, but all about It."— .

" An engineraan who has mastered the contents of Mr. Reynolds's book will require but little actu.!! cxpterience with boilers and engines before he can be trusted to look after thenu'-ifn/urA A/erAn/tiCm

" The book shoukl be possessed by every intelBgent and ambitions enginexnan."— j9Mtf</r.

Continuous Eailway Brakesi

CONTINUOUS RAILWAY BRAKES: A Practical Treatise on the several Systems in Use in the United Kingdom; their Construction and Performance. With copious Illustrations and numerous Tables. By Michael Reynolds. Large crown 8vo, 95. cloth.

" A popular explanation of the dilTerent brakes. It will be of great assistance in forming puKlic optiiion. and will be studied with benefit by those who take an intcrrst in the brake. . . . It is a ck-.tr exposition of the brake question as it relates to the rival syXcms."— Eti£Ush Meehanir.

" Written with snfBdent technical detail to enable the principle and relative connection of the t.irioas parts of eodi particular brake to be readily grasped."— ArrAa/itnt/ ff'tfrU.

" .May be recommended to all who desire to study the subject of continuous brakes."— /ri?/*.

EngineJDriving Life.

ENGINE-DRIVING LIFE: or. Stirring Adventures and Incidents in the Lives of Locomotive-Engine Drivers, By Michabi. Reynolds. Eighth Thousand. Crown 8vo, 2s. cloth.

"The book from first to last Is perfectly fascinating. Wilkie CoDins' most thrilling conceptions tin thrown into the shade by Uue Incidents, endless in their variety, related in every page."— AV'X* BrUish Mail.

" Anyone who wislMS to get a real insight into railway life cannot do better dian read ' Engine- Driving Life ' for himself I and if he once takes it up he will find that the author's enthusiasm and tpal love o( the engine-driving profession will carry him on till he has read every %S9."--iMturdty Jinierc.

Architecture, building, eu. li

ARCHITECTURE, BUILDING, etc.

Construction*

THE SCIENCE OF BUILDING : An EUmentary Treatist on

the Principles of Construction. By E. Wyndham Tarm, M.A., Architect. Second Edition, Revised, with 58 Engravings. Crown 8vo, 75. 6d. cloth. A very valuable book, which we strongly recommend to all students."— BuiUfer.

" No architectural student should be without this handbook of constructional knowledge. ytrcMUect.

Villa

A HANDY BOOK OF VILLA ARCHITECTURE: Being a Series 0/ Designs for Villa Residences in various Styles. With Outline Specifications and Estimates. By C. Wickbs, Architect, Aathor of "The Spires and Towers of England," &c. 30 Plates, 4to, half-morocco, £1 is, Also an Enlarged Edition of the above. 6z Plates, with Outline Specifications, Estimates, &c. £2 25. half-morocco.

" The whole of the designs bear evidence of their being the work of an artistic architect, and tiicy will prove rcry valuable and suggestive."— J?ui/</t/a! News.

Useful Text'Book for Architects.

THE ARCHITECTS GUIDE: Being a Text-Book of Useful Information for Architects, Engineers Surveyors, Contractors, Clerks of VVorks, &c. &c. By Frederick Rogers, Architect, Author of " Specificacions for Practical Architecture," &c. Second Edition, Revised and Enlarged. With numerous Illustrations. Crown Svo, 6s. cloth.

" As a text'book of useful Information for architects, engineers surveyors, ice. It would hard to find a handier or more complete little volume." — Statutard.

"A young architect could hardly have a better guide-book."— r/ziirr Trades yumal.

Taylor and Cresys Monte.

THE ARCHITECTURAL ANTIQUITIES OF ROME. By the late G. L. Taylor, Esq., F.R.I.B.A., and Edward Cresy, Esq. New Edition, thoroughly revised by the Rev. Alexander Taylor, M.A. (son of the late G. L. Taylor, Esq.), Fellow of Queen's College, Oxford, and Chaplain of Gray's Inn. Large folio, with 130 Plates, half-bound, £3 3s.

N.B.--Thi8 is the only book which gives on a large scale, and with the precision of architectural measurement, the principal Moanments of Ancient Rome in plan, elevation, and detail.

" Taylor and Cresy 's work has from Its first publication been ranked among those professional which cannot be bettered. ... It would be difficult to find examples of drawings, even atnong those of the most painstaking students of Gothic, more thoroughly worked out than are the uiie hundred and thirty states in this volume.".— ncAtVircf.

Drawing for Builders and Students in Architecture.

PRACTICAL RULES ON DRAWING, for the Operative Builder and Young Student in Architecture. By Gborob Pynb. With J4 Plates, 4to, ys. 6d. boards.

Specifications for Practical Architecture.

SPECIFICATIONS FOR PRACTICAL ARCHITECTURE : A Guide to the Architect, Engineer, Surveor, and Builder; with an Essay on the Structure and Science of Modern Buildmgs. By Fredbricr Rogers, Architect. With numerous Illustrations, demy Svo, 155. cloth,

A volume of specifications of a practical character being greatly required, and the old si.-iiulard work of Alfred Bartholomew being out of print, the author, on the oasis of that work, hits produced the above.— it.aar/v<-/y >viw Pre/uct.

The House-Owners Estimator.

THE HOUSE-OWNER*S ESTIMATOR ; or. What will it Cost to Build, Alter, or Repair? A Price Book adapted to the Use of Unprofessional People, as well as for the Architectural Surveyor and Builder. Bv the late Jambs D. Simon, A.R.I.B.A. Edited and Revised by Francis T. W. MiLLBR, A.R.I.B.A. With numerous Illustrations. Third Edition, Revised. Crown 8vo, 3s. 6d. cloth.

In two years it will repay its cost a handled times orer,*''Fifid,

A very handy hook,"— Stviiah Aftckanic,

li CROSB V LOCK WOOD iS CO.'S CA fA LdG

Civil Architecture.

THE DECORATIVE PART OF CIVIL ARCHITECTURE. By Sir William Chambers, F.R.S. With lUustratioDS, Notes, and an Examination of Grecian Architecture, by Joseph Gwilt, F.S.A. Edited by W. H. Leeds. 66 Plates, 4to, sis. clotii.

Designing, Measuring, and Valuing.

THE STUDENTS GUIDE to the PRACTICE of MEASUR- ING AND VALUING ARTIFICERS' WORKS. Containing Directions for taking Dimensions, Abstracting the same, and bringing the Quantities into Bill, with Tables of Constants, and copious Memoranda for the Valuation of Labour and Materials in the respective Trades of Bricklayer and Slater, Carpenter and Joiner, Painter and Glacier, Paperbanger, &c With 8 Plates and 63 Woodcuts. OriginalW edited bv Edward Dobson, Architect. Fifth Edition, Revised, with considerable Additions on Mensuration and Construction, and a New Chapter on Dilapidations, Repairs, and Contracts, by E. Wymdham Tarn, M.A. Crown 8vo, 95.

Well fulfils the promise of Its title-page, and we can thorooffhly recommend It to the class for whose use it has been compiled. Mr. Tarn's additions and revisions have much increased the usefulness of the work, and have espedaDy augmented its value to students."—

"The work has been carefully revised and edited by Mr. E. Wvndhara Tarn, M.A., and comprises several valuable additions on construction, mensnration, dilapidations and repairs, and other matters. . . . This edition will be found the most complete treatise on the principles of measur. ing and valuing artificers' work that has yet been published."— Mt/t/iVtf'AVvtf.

"Might be read and studied with advantage by almost everyone having any cgnnectf on with building operations, from the architect dovnwaxdtr—BuiUliHg JFarltU

Pocket Estimator.

THE POCKET ESTIMATOR for the BUILDING TRADES., Being an Easy Method of Estimating the various parts of a Building coUec* tively, more especially applied to Carpenters' and Joiners' work. By A. C. Beaton, Author of Quantities and Measurements." Third Bdiition, carefully revised, 33 Woodcuts, leather, waistcoat-pocket size, is. 6d.

" Contains a good deal of Information not easily to be obtained from the ordinary price books. The prices given are accurate, and up to date."— Bui/ding' News.

" This book b as complete as it is possible to make it."— BMildOtf and Eni$uerittg Times.

Builder's and Surveyor's Pocket Technical Guide.

THE POCKET TECHNICAL GUIDE AND MEASURER FOR BUILDERS AND SURVEYORS. Containing a Complete Explana. tion of the Terms used in Building Construction, Memoranda for Reference, Technical Directions for Measuring Work in all the Building Trades, with a Treatise on the Measurement of Timber, Complete Specifications, &c., &c. By A. C. Beaton. Second Edition, with 19 Woodcuts, leather, waistcoatpocket size, is. td. "An exceedingly handy pocket companion, thoroughly reliable."- iwtitfrr'x ffeeJtfy Refprter,

" This neat little compendium contains aU that is requisite in canryiog out contracts for excavating, tiling, bricklaying, paving, ecc"— British Trade

Handbook of Specifications.

THE HANDBOOK OF SPECIFICATIONS; or. Practical Guide to the Architect, Engineer, Surveyor, and Builder, in drawing up Specifications and Contracts for Works and Constructions. IllnstratM by Precedents of Buildings actually executed by eminent Architects and Engineers. Bv Professor T. L. Donaldson, P.R.I.B.A., &c. New Edition, in One large vol., 8vo, with upwards of 1,000 pages of Text, and 33 Plates, £1 lu. 6d, doth.

" In this work forty-four specifications of executed works are Eivei Inclndiag the fpir'fiTfitions for parts of the new Houses of Parliament, by Sir Cliarlea Barry, and for the new Royal Exchange, by Mr. Tite M.P. The latter, in particular, is a very complete and remarkaola document, ft embodies, to a great extend as Mr. Donaldson mentions, 'the bill of quantities with the description of the works.' ... It b valuable as a record, and more valuable still as a book of precedents. . . . Suffice it to say that Donaldson's 'Handbook of Spedficatlons' must be bought by all architects."— iM/iSifrr.

Boiler and Factory Chimneys.

BOILER AND FACTORY CHIMNEYS: Their Draught-power and Stabilitv : with a Chapter on Lightning-Conductors. By Robert Wix SON, C.E., Author of "Treatise on Steam Boilers." Cr. 8vo, 3s. 64. cloth. A most valuable book of Its kind, full of useful infotmatJon.*— JLmo/ Government CMrenide,

DECORATIVE ARTS, tie. 13

DECORATIVE AKTB, etc

Woods and Marbles (Imitation of).

SCHOOL OF PAINTING FOR THE IMITA TION OF WOODS AND MARBLES, u Tiaitht ind Practised byAR- Van pii Buna aod P.

i9t br iiliB.Jl'luwntedwTihufaJl'ieColaiired'pIiteii'iiFliinPlaiH cempritiDi 154 Flfurei, prk* £t lu. CiJ.

Lilt 0/ Conlmlt lnlTVdKlOfT — Tooli rwiolrtd ID

—irfiu

IVKHl-Adi ; PalBOH at Aib-Brecto iBn -

[iilMirbla: Bnchi Vloklle : Inc-Miilki ! FIOCM or Wsiklne— Tlw diTttuI unctcs al Mlibli : MnUdl of Working :

Colour.

A GRAMMAR OP COLOURING. Applied to Decorativo Painting lad Iha Aita. BrGioioi Fiau). NawEdllion, adapted la iba iiH oftbaOrnamanUlFalaleraiidDMigncc. BjEu-isA. Datidsdn, With New Coloured Diafirama and BaKrariagi. lamo, s>' cLolh boards.

Olasa Painting,

GLASS STAINING AND THE ART OF PAINTING ON CLASS. PiointbeGermaDof Dr.GiesiiiTand Euihuil Otto PaouBtno With an Appendix OB Tita Ait of Ehakelliho. lamo, u. td. doth limp

Xtecoration.

DoelliDg Hoosea, ftc Bj Jauu W. Full, Jan. WithesCule. I

cloth limp.

Aa '-fc-ii fDld*4ooL 10 tlto dACDrUlrt palBtAt U wniba ttound it:itHa.'—3Hatiiijf'twL

House Fainting, etc.

House Painting, Graining, Marbling, And Sign

WRITING. A Practical Uan With CDlonred pun

id Wood EngraviDgi,

14 Crosby Lock Wood S- Co,*S Catalogue,

DELAMOTTE'S WORKS on ILLUMINA TION & ALPHABETS.

A PRIMER OF THE ART OF ILLUMINATION, for the Use of Beginners : with a Rudimentary Treatise on the Art, Practical Directions for its exercise, and numerous Examples taken from Illuminated MSS., printed in Gold and Colours. By F. Delauottb. Small 4to, 9s. elegantly bound, cloth antique.

" . . . . The examples of ancient MSS. recommended to the student, which, with much eood sense, tite author chooses Trom collections accessible to al are selected with judgment and Knowledge, as well as taste.'—A/Ae/taum,

ORNAMENTAL ALPHABETS, Ancient and Mediaval from the Eighth Century, with Numerals; including Gothic, Church-Text, large and small, German, Italian, Arabesque, Initials for Illumination, Monogratus, Crosses, &c., &c., for the use of Architectural and Engineering Draughtsmen, Missal Painters, Masons, Decorative Painters, Liinographers, Engravers, Carvers, &c., &c. Collected and Engraved by F. Delamottb, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, 2S. 6d. ornamental boards.

"For those who Insert enamelled sentences round gilded chalices who blazon shop legends ovr shop-doors, who letter church walls with pithy sentences from the Decalogue, this book will bo use* ful. — AtJuiurunt.

EXAMPLES OF MODERN ALPHABETS, Plain and Ornamental; including German, Old English, Saxon, Italic, Perspective, Greek, Hebrew, Court Hand, Enossing, Tuscan, Riband, Gothic, Rustic, and Arabesque; with several Original Designs, and an Analysis of the Roman and Old English Alphabets, large and small, and Numerals, for the use of Draughtsmen, Surveyors, Masons, Decorative Painters, Lithographers, Engravers, Carvers, &c. Collected and En{;raved by F. Delamottb, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, 25. 6d, ornamental boards.

" There is comprised in it trrtry possible shape into which the letters of the alphabet and numerals can be formed, and the talent which has been expended in tlie conception of the various plain and ornamental letters is wonderful."— Au/an/.

"This volume has borne the test of practical use, and is Invariably oken ircU of by those who possess \t.''—y€W€ and MeUU-vtmrker*

MEDimVAL ALPHABETS AND INITIALS FOR ILLUMI- NA TORS. By F. Delamotte, Illuminator. Designer, and Engraver on Wood. Containing 21 Plates and Illuminated Title, printed in Gold and Colours. With an Introduction by J. Willis Brooks. Small 4to, 6s. cloth gilt.

" A volume in which the letters of the alphabet come forth glorified ingildjag ahdall the colours of the prism interwoven and inttwined and intermingled. "-nSmm.

THE EMBROIDERER'S BOOK OF DESIGN. Containing Initials, Emblems, Cyphers, Monograms, Ornamental Borders, Ecclesiastical Devices, Mediaeval and Modem Alphabets, and National Emblems. Collected by F. Delamottb, and printed in Colours. Oblong royal 8vo, is. td., ornamental wrapper.

" The designs are practical—not designs that cannot be done In embroidery ; and the book will no doubt found exceedingly useful in tne lady's work-room and in Coiirant.

" The book will be of great assistance to ladies and voung children who are endowed wi'h the art of plying the needle in this most ornamental and osenil pretty work."— Jb'ox/ Anglian Times.

Wood Carving.

INSTRUCTIONS IN WOOD-CARVING, for Amateurs; with Hints on Design. By A Lady. With Ten large Plates, 25. 6d. in emblematic wrapper.

"The handicraft of the wood-carver, so well as a book can impart it, may be learnt from ' A Tody's ' publication." — AtJunaum.

" The directions given are plain and easily understood."— ir/tjA .fechatiU.

Letter Painting.

THE ART OF LETTER PAINTING MADE EASY, By

JAMB8 Grbiq Badenoch. With 12 fall-page Engravings ot Examples, is. cloth imp. , " The system Is a simple one. but quite original, and well worth the careful attention of Initer It can easily mastered and remembered. "—i/rTr/Ov AVn f,

CARPENTRY, TIMBER, etc. 15

CARPENTRY, TIMBER, etc.

TredffoUVs Carpentry, Enlarged by E. !F, Tarn,

THE ELEMENTARY PRINCIPLES OF CARPENTRY. A Treatise on the Pressoro and Equilibrium of Timber Framing, the Resist* ance of Timber, and the Construction of Floors, Arches, Brioges, Koois, Uniting Iron and Stone with Timber, ftc. To which is added an Essay on the Nature and Properties of Timber, &c., with Descriptions of the kinds of Wood used in Building ; also numerous Tables of the Scantlings ot Tim* ber for different purposes, the Specific Gravities of Materials, &c. By Thomas Trbdgold, C.E. With an Appendix of Specimens of Various Roots of Iron and Stone, Illustrated. Sixtn Edition, thoroughly revised and considerably enlarged bv E. Wvndham Takn, M.A., Author of "The Science of Building," Ac. With 6z Plates. Portrait of the Author, and several Woodcuts. In one large vol., 4to, price £i 5s. cloth. CJfsf published,

Ought to ba in erery architect's aiul every Dander's library.'*— J9n//.

"Tredfold's Elementarr Principles ff Carpentry' is without doubt, the standard English authority upon the subiect. Mr. Tarn, b3r supptementing the text of the author, adds much to tlie work, and nakes it an indispensable addition to the the student, the architect, and tie engineer. "— if ii ildittg .

Woodtvorking Machinery,

WOODWORKING MACHINERY : Its Rise, Progress, and ConstmctioH. With Hints on the Management o( Saw Mills and the Economical Conversion of Timber. Illastrated with Examples of Recent Designs by leading Eziglish, French, and American Engineers. Bv M. Powis Balk, A.M. Inst. C.B., M.I.M.E. Large crown 8vo, 135. 6d. cloth.

" Mr. Bale is evidently an expert on the subject, and he has collected so much infonnstion (hat his book is aU-suffideat for builders and others engaged in the conTersion of tunbcr."— W rchitert.

"The most comprehensive compendium of wood'Working machinery we have seen. The uthor is a thorough master ef bis saoloct,"— Building News.

" Converters of timber, wholesale Joiners, the members generally of the Duilding trades, architects, andowaers of and dealers in timber, owe Mr. Bale tribute to the value of the cost of Lis book. It is sound from end to end, well designed and well cxocuted."— /ro/i.

" The appearance of this book at the present time will, wo should think, give a considerable impetus to the onward march of the machinist enijaKod in the designing and manuracture uf wood-working machines. It should be in tlte office oi' every wood-worlung factory ;//j-A

Haw Mills,

SAW MILLS: Their Arrangement and Mancgemenf, and the Economical Conversion of Timber. (Being a Companion Volume to " Wooc<- working Machinery.") By M. Powis Bale, A.M. Inst. C.E., M.I.M.E. With numerous Illustrations. Crown Svo, los. dd. cloth.

" The author is favourably known by his former work on Woodworking Machinery, of which we were able to speak approvingly. This is a companion vulnmc, tn the attoti ol a Ltrge drawing estabKshment is discussed, and the subject examined frtmi a fmancial st.niKlpiMiit. HcBCc the sixe, shape, order, and dispo<>ition of saw-mills and the like arc cone into in rict.ii , and the course of the timber is traced from its reception to its delivery in Its convettc-d s.atc. We could not desire a more complete or practical treatise."—

"We highly recommend Mr. Bale's work to the attention and peniul of all those who are engaged in the art of wood conversion, or who are about building or reuiodelHng siw-mills on proved principles."'— News.

"Will be found of much value by that special class of readers for whose inforin.-itinn it Is do* signed. We recommend the book to those about to construct or to manage saw-miUs."— W/A/ia'Hw.

Undertvood and Woodland Tables,

TABLES FOR PLANTING AND VALUING UNDER- WOOD AND WOODLAND ; also Lineal, Superficial, Cubical, Waf:cs, Marketing, and Decimal Tables. Together with Tables for Convertirg Landmeasure from one denomination to another, n.ud Instructions ior Measuring Round Timber. By Richard Horton. i2me, 25. strongly bound in leather.

Cn rpenterin g,

THE CARPENTER'S NEW GUIDE ; or, Book of Lines for Carpenters: comprising all the Elcmentarv Principles essential for acquiring a knowledge of Carpentry. Founded on the late Petrr Nicholson's Standard Work. A New Edition, revised by Arthur Ashpitel, F.S.A. Together with Practical Rules on Drawing, by Ceorce . With 74 Platcft. 4to, IS. cloth.

i6 CROSBY LOCKWOOD & CO,' S CATALOGUE.

Thnher Merchant's Companion,

THE TIMBER MERCHANTS AND BUILDER'S COM- PA NION. Containing New and Copioas Tables of the Reduced Weight and Measurement of Deals and Battens, of all sides, from One to a Thousand Pieces, and the relative Price that each size bears per Lineal Foot to any Riven Price per Petersburg Standard Hundred ; the Price per Cube Foot en Square Timoer to any given Price per Load of 50 Feet; tne proportionate Value of Deals and Battens by th6 Standard, to Square Timber by the Load of 50 Feet ; the readiest mooe of ascertainmg the Price of Scauatling per Lineal Foot of an3r size, to any given Figure per Cube Foot. Also a variety of other valuable information. By William Dowsing, Timber Merchant. Third Edition, Revised and Corrected. Crown 8vo, 3s., cloth.

" Everythinflf Is as concise and clear as it can poasibly be made. There can be no doubt that every timber merchant and builder ought to possess it."— //m/ Advertiser,

" We are gaul to see a third edition of these admirable tables, which for correctness and simplicity of artangenwnt leave nothing to be desired."— TiMr Trades jfoumcU.

I*racticaZ Timber Merchant,

THE PRACTICAL TIMBER MERCHANT. Being a Guide for the nse of Building Contractors, Surveyors. Builders, Ac, comprising useful Tables for all purposes connected with the Timber Trade, Marks of Wood, Essay on the Strength of Timber, Remarks on the Growth of Timber, &c. By W. Richardson. Fcap. 8vo, 3s. Od. clQth.

" This handy manual contains much valuable Information for the use of timber merchant* builders, foresters and all others connected with the sfrowth, saK and manufacture of timi;er.' — yournml Forestry.

"To timber merchants or users this compact treatise will be fbuad very vaeivl."—IUustrated Carpenter.

Timber Freight Book.

THE TIMBER MERCHANTS, SAW MILLER'S, AND IMPORTER'S FREIGHT BOOK AND ASSISTANT. Comprising Rules, Tables, and Memoranda relating to the Timber Trade. By William Richardson, Timber Broker; together with a Chapter on "Speeds of Saw Mill Machinery,'' by M. Powis Bale, M.I.M.E., etc, zsmo, ss. 6d, doth.

Tables for Packing-Case Makers.

PACKING-CASE TABLES ; showing the number of Superficial Feet in Boxes or Packlng'Cases, from six inches square and upwards. By W. Richardson, Timber Broker. Second Edition. Oblong 4to, 3s. 6d,

Win save much hibour and calculation to makers and users of pacldnff*cases."— . Invaluable labour-saviaff tables.'— /rvniMMVvr

Superficial Measurement.

THE TRADESMAN'S GUIDE TO SUPERFICIAL MEA- SUREMENT. Tables calculated from z to aoo inches in lena, by 1 to 108 inches in breadth. For the use of Architects, Surveyors, Engineers, Timber Merchants, Builders, &c By Jambs Hawxinos. Third Edition. Fcap., 3s. 6d. cloth.

Forestry.

THE ELEMENTS OF FORESTRY. Designed to afford Information concerning the Planting and Care of Forest Trees for Ornament or Profit, with Suggestions upon the Creation and Care of Woodlands. By F. B. Hough. Large crown 8vo, los. cloth.

Timber Importer's Guide*

THE TIMBER IMPORTER'S, TIMBER MERCHANTS AND BUILDER'S STANDARD GUIDE. By Richard E. Grandy. Comprising an Analys of Deal Standards, Home and Foreign, with Comparative Values and Tabular Arrangements for fixing Nett Landed Cost on Baltic and North American Deals, including all intermediate Expenses, Freight, Insurance, &c., &c. ; together with copious Information tor the Retailer and Builder. Second Edition, carefully revised and corrected, xamo, 35. 6d, cloth boards.

Everythinfr it pretends to be : built up gradually, It leads one from a forest to a treenail, and throws in, as a makeweight, a host of material concerning bricks, columns, cistern ttc—Engiish Mechanic,

titNtNG AUD iiWllJG INDUSTRIES. '7

Miming And Mininq Indttstbies.

Mining in the United Kingdom,

BRITISH MINING: A Jnatiu oa tht Hutory.Diseettty.Practieet DnilopmnI, and Fulute Pnitult 0/ Uttattijtnui Uaa in thi Uniltd Kinf dam. Bj Roniv Kukt, F.R.S., of MioiDg Rscordi; Editor of Un Diclionai? of Ani, MiDuficlurei, ud UiD,''&c Upwudi of gju pp., with 130 llluitnitiont. Suptr-coriil aro, 31. cloth.

[>cnipittoB. — III. HIidAf n Uia

fiA Coapcr 10 tha End at entiin..-V. MUw Kit iMit. SilM, tt~, 10 iba Esd or tht ElilinaiiihCwun.— VL <;oJd, Plumhan lioa Oev, Uk) SuildHH tO tba End of (ho CvHuir

JBPOSnS--Cli.(i.I.Tli.Kocti

8MbL Dinrica, ud tin DiKHInjlIni of

Co€il and Iron.

THE COAL AND IRON INDUSTRIES OF THE UNITED KISCDOM. Compriiing DeKtlplion of tho Corf Fields. nd of Ibe Principal Seami of Coal, with Relumi of their Pioduci and ill Dinribullon. and Aiialj9ci of Special Varieiiei. Alio an Aecoont of (he occniranca of Iron Ores io Veini or Seami; Analrasi of ch Vaiiely ; ud Hiiloir of th> RiH and Pisgreu of Pi lion Mannfactiua uica the Tear 1740, sibiUdng tha niSB RicHAW m'Ld A? "™""' " nan mo ™.

Mapa of tha Coal Fieldi and Ir Sn, £1 Si. cloUi.

i8 CROSDV LOCKlVOOl:) CO,'S CATALOGUE,

phate of Lfme. PART IIT. Carbon and Coinpounds of Carbon — Sulphur. Part IV. Arsenic — Cobalt — Molybdenum — Antimony and Manganese — Classified List of Mineral Substances.

Metalliferous Minerals and Mining,

TREATISE ON METALLIFEROUS MINERALS AND MINING. By D. C. Davies, F.G.S., Minins; Engineer, &c., Author of " A Treatise on Slate and Slate Quarrving." Illustrated with numerous Wood Engravings. Second Edition, carefully Revised. Crown 8vo, 12s. 6d. cloth. " Neither the practical miner nor the general reader interested In mines, can have a better bouk

for his companion and his guide."— .min youmal

" A boolc that will not only be aseftil to the geologist; the practical miner, and the metallurgist ;

but also very interesting to the general public." — IrH,

" As a history of the present state of mining throughout the world this book has a real tsIu,

and it supplies an actual want, for no such information nas hitherto brought together within

limited space." — jitheuceum.

Earthy Minerals and Mining.

A TREATISE ON EARTHY AND OTHER MINERALS AND MINING. By D. C. Davies, F.G.S. Uniform with, and forming a Companion Volume to, the same Author's " Metalliferous Minerals and Mining." With 76 Wood Engravings. Crown 8vo, izs. 6d. cloth.

Summary of Contents :

Part I. SIHcftAIunilna— Lime— Magnet — Glucina — Zircon!* — Thoria— -ith some of their combinations. PART II. Chloride of Sodium (Common Salt) — Nitrate of Soda— Borax— Baryta— Gypsum— Alum Shade— Phos-

" It is essentially a practical work. Intended primarily for the use of practical men. . . . We do not remember to have met with any English work on mining matters that contains the same amount of information packed In equally convenient (oxm."— Academy.

Underground JPumping Machinery.

MINE DRAINAGE. Being a Complete and Practical Treatise on Direct-Acting Unde;roujid Steam Pumping Machinery, with a Description of a large number of the best known Engines, their General Utility aud the Special Sphere of their Action, the Mode of their Application, and their merits compared with other forms of Pumping Machinery. By Stephen MiCHELL. 8vo, 155. cloth.

"Wa be highly esteemed bv colliery owners and lessees; mining engineers, and students fteneratly who require to be scquamted with the best means of secnrinf the drainage of mines. Ic IS a most valuable work, and stands almost alone in the literature of steam pumping machinery."— CoUicry Guardian,

Mining Tools.

A MANUAL OF MINING TOOLS. For the Use of Mine Managers, Agents, Students, &c. By William Morgans, Lecturer on Practical Mining at the Bristol School of Mines. x2mo, 3s. cloth boards.

ATLAS OF ENGRAVINGS to Illustrate the above, containing 83s Illustrations of Mining Tools, drawn to scale. 4to, 65. cloth boards.

Students in the science of mining; and overmen, captains, managers, and viewers may gain practical knowledge and useful hints by the study of Mr. Morgans' manual." — Collitry Guardian.

Coal Mining.

COAL AND COAL MINING: A Rudimentary Treatise on. By Warington W. Smyth, M.A., F.R.S., &c., Chief Inspector of the Mines of the Crown. New Edition, Revised and Corrected. With numerous Illustrations. 1 2mo, 4s. cloth -boards.

" As an outline is given of every known in this and other countries, as well as of the prindpal methods of working, Uie book will doubtless interest a very large number of readers."— Mininff youmal.

Mining Surveying.

The Mineral Surveyor And Valuer'S Complete

GUIDE. By William Lintern, Mining and Civil Engineer. With Four

Plates of Diagrams, Plans, &c. lamo, 45. cloth boards.

" Contains much valuable information given in a small compass, and which, as far as we have tested it, is thoroughly trustworthy."— /ro/i and Coal Trades Review.

Subtet'raneous Stirveying.

SUBTERRANEOUS SURVEYING, Elementary and Practical Treatise on; with and without the Magnetic Needle. By Thomas Fen wick, Surveyor of Mines, and Thomas Baker, C.E. Illustrated, lamo, 3s. cloth.

NAVAL AkCltMCTURE, NAVIGATION, eh. NAVAL ARCHITECTURE, NAVIGATION, etc. Bochet-Bookfor Naval Architects and Shipbuilders,

THE NAVAL ARCHITECT'S AND SHIPBUILDER'S POCKET-BOOK of Formula, Rules, and Tables and Marine Engineer' i and Surveyor's Handy Booh of Reference. By Macxrow, Member of the Institution of Naval Architects, Naval Draughtsman. Third Edition, Revised. With numerous Diagrams, &c. Fcap., 12s. 6d. strongly bound in leather.

" Should be used by all who arc cnofacd in the constnictlon or design of vessel. . . . "WW be round to contain the most useful tables and formuke required by sliipbuilders. carefully collected from the best authorities, and put together in a popular and simple fona."-'iittgiue*r.

"The professional shipbuilder has now, in a convenient and accessible form, reliable data for fcolving many of the numerous problems that present themselves in the course of his work."— /r(.

" There is scarcely a subject on which a naval architect or shipbuilder can require to \slt 11 !s memory which will not be found within the covers of Mr. Madcrow'sboolc"— Zi/tf/irA J/rr/rdi( .

JPocket'Book for Marine Engineers.

A Pocket-Book Of Useful Tables And For

MVLM FOR MARINE ENGINEERS, By Frank Proctor, A.I.N.A.

Third Edition. Royal 32mo, leather, gilt edges, with strap, 45.

" We recommend it to our readers as going to supply a long-felt want."— Ainw/Sror. "A most useful companion to all marine engineers."— Mi/Mf Strvice (ioMette.

Qranthams Iron Shipbuilding.

ON IRON SHIPBUILDING, With Practical Examples and Details. By John Grantham, M. Inst. C.E.. &c. Fifth Edition. Imp. 4to, boards, enlarged to 40 Plates, including the latest Examples. Together with separate Text, also considerably enlarged, xamo, cloth limp, price £z as.

complete.

" Mr. Graatham's work is of great interest. . . . It Is also valuable as a record of the progress of iron shipbuilding. ... It will, we are confident, command an extensive circulation amoxig shipbuilaers in general. . . . The text-book on which the examination in Iron shipbuilding of candidates Tor promotion in the dockyards will be mainly based."— it MjriJMrrfMyr*

Lighthouses.

EUROPEAN LIGHTHOUSE SYSTEMS. Being a Report of a Tour of Inspection made in 1873. By Major Georgb H. Elliot, Corps of Engineers, U.S.A. Illustrated by si Engravings and 31 Woodcuts. 8vo, 215. cloth.

Navigation (JPractical) with Tables.

PRACTICAL NA VIGATION. ConsistiDg of the Sailor's Sea- Book, by James Greenwood and W. H. Rosser ; together with the requisite Mathematical and Nautical Tables for the Working of the Problems, by Hbnry Law. C.E., and Professor J. R. Young. Illustrated. i2mo, ys. strongly half-found.

Stomis.

STORMS : Their Nature, Classification and Laws; with the Means of Predictinc; them by their Embodiments, the Clouds. By William Blasius. With Colotired Plates and numerous Wood Engravings. Crown 8vo, xos. 6d. cloth.

"A very readaMa book. . . The fresh facts contained In its pai;:c\ collcctrd witti evident care; form a useful repository to meteorologists in the study of atmosplicrical dlsturUiuc . . . The book will repay perusalas being the production of one who gives evidence of acute ebsaTvalion,"— Nature,

The following books on Naval Architecture, etc., are published in Weals's

Rudimentary Series.

MASTING, MAST-MAKING, AND RIGGING OF SHIPS, By Robert Kipping, N.A. Fourteenth Edition. z2mo, 2s. 6d. cloth boards.

SAILS AND SAIL-MAKING. Tenth Edition, Enlarged, with an Appendix. By Rodrkt Kipping, N.A. Illustrated, izmo, 3s. cloth boarch

NAVAL ARCHITECTURE. By Tames Peaks. Fourth Edition, with Plates and Diagrams. z2mo, 45. cloth boards.

io cHosbV Lockwoob S- CO.'S CATaLOCU, NATURAL PHILOSOPHY AND SCIENCE.

JElectricity*

A MANUAL OF ELECTRICITY : Including Galvanism, Mag-

netisMf Dia-Magnetism, Electro-Dynamics, MagtuhEUctricity, and ths Kleftnc

Telemph. By M. Noad, Ph.D., F.R.S F.C.S. Fourth Editioa.

With 500 WooNicuts. 8vo, £1 4s. cloth.

"The accounts given of dectriclty and galvanism are not only completo b a scientific sense, but, which is a rarer thing, are popular and interestinfif.''— Motf.

" Among the numerous writers on the attractive and fascinating subject of electricity, the author of the present volume has occupied our best attention. It is worthy of a pbice in the library of every public institution, and we have no doubt it will be deservedly patronised by the scientific community.'*— //vti/' yumaL

Text Book of Electricity.

THE STUDENTS TEXT-BOOK OF ELECTRICITY. By M. Noad, Ph.D., F.R.S., F.C.S. New Edition, carefully Revised. With an Introduction and Additional Chapters, by H. , M.I.C.E., Vice-President of the Society of Telegraph Engineers, &c. With 470 Illnstrations. Crown 8vo, 12s. 6d. cloth.

" The original plan of this book has been carefully adhered to so as to make it a reflex of the existinfif state of electrical science, adapted for students. . . . Discovery seems to have pro* grossed with marvellous strides ; nevertheless it has now apparently ceased, and practical ammcations have commenced their career : and it is to give a faithful account of these that this fresh edition of Dr. Noad's valuable text-book is launched forth."— SjnCrtter/rMw ItUroimctttn ky H. Pect, Esq.

We can recommend Dr. Noad's book for dear style, great range of subject a good indei and a plethora of woodcuts. Stich collections as the present are hidispensable.*— Mmmrmpi.

"An admirable teat-book for every student— beginner or advanced— of electrldty."— BngOuering,

"AfflostdatKXBtacompOatian of the fiicts of clectrid and magnetism."— /VMiktr SdicMca Rgoitw,

" Dr. Noad's text-book has earned for itself the reputation of a truly scientific manual for the student of electridty, and we gladly hail this new amended edition, which brings it once more to the front. Mr. Preece as reviser, with the assistance of Mr. H. R. Kempe and Mr. J. P. Edwards, has added all the practical results of recent invention and research to the adminSle theoretical expositions of the author, so that the book is about as complete and advanced as it is possible foe any book to bo within the Umitt of a text-book."— rr/<raJUc Jvumal,

Ihr. Lardnera School Handbooks.

NATURAL PHILOSOPHY FOB SCHOOLS. By Dr. Lardnbr.

328 Illustrations. Sixth Edition. One Vol., 3s. 6d. cloth.

" A very convenient class-book for junior students in private schools. It is Intended to convey. In dear and prcdse terms, general notions of all the pnndpal divisions of Physical Science."— British Qnartiriy Review.

ANIMAL PHYSIOLOGY FOR SCHOOLS. By Dr. Lardner. With X90 Illustrations. Second Edition. One Vol., 3s. 6d. cloth. " Clearly written, well arranged, and exceOeutly illustrated."— an&fMr'f ChrotiicU,

lAirdner'8 Electric Telegrajyh.

THE ELECTRIC TELEGRAPH. By Dr. Lardner. New Edition. Revised and Re-written by E. B. Bright, F.R.A.S. 140 lUustra* tions. Small 8vo, 25. 6d. cloth. " One of the most readable books extant on the Electric Telegraph."- iffiy/A Meckanie.

Field Fortification.

A TREATISE ON FIELD FORTIFICATION, THE ATTACK OF FORTRESSES, MILITARY MINING, AND RECONNOITRING. By Colonel I. S. Macaulay, late Professor of Fortification in the R.M.A., Woolwich. Sixth Edition, crown 8vo, cloth, with separate Atlas of 12 Plates, zu. complete.

Idghtning.

THE ACTION OF LIGHTNING, and the Means of Defending Life and Property from iU Effects. By Major A. Parnell. R,E. iimo, ys. 6d, cloth.

hasp tube

Major ParneD has written an original work on a sdentiiic subject of unusual interest : and pre&ced hw aivuinents by a,patient and almost exhausUva station of the best writers on tha [ect In the English language."— v</AtfyurKM

Natural Philosophy And Science. 21

Oeoloffy and Genesis.

THE TWIN RECORDS OF CREATION; or, Geology and Genesis : their Perfect Harmony and Wonderful Concord. Bv Georob W, Victor lb Vaux. Numerous Illustrations. Fcap. 8vo, 5s. doth. "A valuable contribution to the evidences of revelioion, and disposes very conclusively of th

arguments of those who would set Cod's Works against God's Word. No nai difficulty b shirked.

aud no sophistry is left unexposed."— r/tf A'acJt.

"The remarkable peculiarity of this author Is that ho combines an unbounded adairatkm of dence with an uubouaded admiration of the Written Record. Tlie impulses are balanced to a nicety ; and the consequence is that dtfficultlea which to minds less evenly poised would be serious find immediate solutions of the happiest kHais,"— London Radrw,

The Blowpipe.

The Blowpipe In Chemistry, Mineralogy, And

3s. 6d. cloth.

Contents :

phte Reactkms of Metals and AOogrtd— XX. On

CHAP. I. Maoufhcture of Blowliw Apparatus. II. Construction of Pyroloeical Lamps.— II. Supports and Aoparatus.— IV. On Auxiliary Apparatus.— V. On the Structure and Manag> tnent of Pyrocones.— VI. On Pvrolosical Re> agents.— Vfl. On Reasfentsand Shnple Mineral Aiulyses.— VIII. Fint Operations : Aluminlum-

Pyrological Mineralogy and a New Spedfic Gravitometer. — X. Inner Caldum-pnoboiate Balls. "Chemical Water." &c.— XI. Rationale of Outer and Inner Ball Formation in Boric Add before the Blowpipe. — XII. Frieberg Qualitative Examples.

"The student who goes conscientiously through the coune of experlmentatioa here laid down w'll gain a Indght into inorganic chemistry and than if he bad 'got up' any of the best text-books of the day, and passed any number of examinations In their contents.*-CAMi ca/ AVatf.

The Military Sciences.

AIDE-MEMOIRE TO THE MILITARY SCIENCES. Framed from Contributions of Officers iind others connected with the diffarant Services. Originally, edited by a Committee of the Corps of Royal Engineers. Second Edition, most carefully revised an Officer of the Corps, with many Additions; containing nearly 350 Engravmgs and many hundred Woodcuts. Three Vols., royal 8vo, extra cloth boards, and lettered, £4 xoc.

"A compendious encyclopaedia of military kaowledga to which we are gntOj Indebtod." bdtnbMrph RtvUw.

" The most comprefaendve work of lefiarenoe to tiie mllltnry and coOatacal idences.*— >Vflwi. tKr Service Gatutte,

Astronomy.

ASTRONOMY. By the late Rev. Robert Main, M.A., F.R.S., formerly Raddiffe Obserrer at Oxford. Third Edition, Reviaed and Corrected to the present time, by William Thymnb , B.A., F.R.A.S., formerly of the Rojral Observatory, Greenwich, zamo, as. cloth limp. A KMmd and simple treatise, veiycarefliDy edited, anda capital book for beginnan.*— Arnatv*

"The pretent edition seems to have been carefully and aceuntdy brought down to the requirements (MT tne present time by Mr. Lyva."— Educational Times,

Oedogy.

GEOLOGY, Physical and Historical. Consisting of "Physical Geology," which sets forth the leading Principles of the Science and " Hiatoricai Geology," which treats of the Mineral and Conditiona of the Earth at each successive epoch, especial reference being made to the British Series of Rocks. By Ralph Tatb. A.L.S., F.G.S., &c., &c With over 230 Illustrations. lamo, 5s. doth boards.

The flihiess of the matter has elevated the book into a maauaL Its Infonnatlaii Is eslmustlve and well arranged."-ScA0/ Board Ckronide,

Conehology.

MANUAL OF THE MOLLUSCA : A TreaHsi on Recent and Fossil Shells, By Dr. S. P. Woodward, A.L.S. With Appendix by Ralph Tate. A.L.S.. F.CS. With numerous Plates and 300 Woodcnts. Handsomely bound in cloth boards, 7s, 6d,

"A moct vahmble storehouse of conchologlcal and geofaglcsl infocnatloii.''— /fa'i''f Scienct Gosii/.

22 Crosby Lockivood & Co.' S Catalogue.

Dr. LARDNER'S HANDBOOKS of NATURAL PHILOSOPHY.

Tiu following five volumes though each is complete in itself, and to be purchased separately, form A Complstb CToursb of Natural Philosophy. The style is studiously popular. It has been the author's aim to supply Manuals for the Student, the Engineer, the Artisan, and the superior classes in Schools.

THE HANDBOOK OF MECHANICS. Enlarged and almost rewritten by Benjamin Loewy, F.R.A.S. With 378 Illustrations. Post 8vo, 6s. cloth.

" The perspicuity of the original has been retained, and chapters which had become obsolete hare been replaced by others of more modem character. The explanations throughout are s:uiHously popular, and care has been taken to show the application of the various branches of physics to the industrial arts, and to the practical business of life."— yottnial.

" Mr. Loewy has carefully revised the book, and brought it up to modem requirements. Nature.

" Natural philosophy has had few exponents more able or better skilled In the art of popu

lariiting the suDject tlian Dr. Lardnrr ; and Mr. Loewy is doin? fiTood service in fitting this treatise and tli others of the series, for um: at tlie present time." — Scotsman.

The Handbook Of Hydrostatics And Pneumatics.

New Edition, Revised and Enlarged by Benjamin Lobwy, F.R.A.S. With

236 Illustrations. Post 8vo, 55. cloth.

"For those 'who desire to attain an accurate knowledge of physical science without the profound methods of mathematical invesUcatioo.' this work is not merely intended, but well adapted." — CIutHiial News.

The volume before us has been carefully edited, auraented to nearly twice the buDc of the former edition, and ail the most recent matter has been added. . . . It is a valuable —Aature.

" Candidates for pass examinations will find it, we think, specially suited to their requirements." liUflish Atechanic.

THE HANDBOOK OF HEAT. Edited and almost entirely re

written by Benjamin Loewy, F.R.A.S., &c. 1x7 lUtistrationa. Post 8vo, Gs.

cloth.

"The style h always clear and precise, and conveys Instruction wUbout leavlniany cloudiness or lurking doubts behind." — Eneineerinff.

" A most exhaustive book on the subject on which it treats, and is so arranged that it can be

understood by &U who desire to attain an accurate knowl<.-d(!e of physical science Mr.

Loewy has included all the latest discoveries in the varied laws and effects oiyxvA."— Standard.

" ▲ compleja and handy text-book for the me of students and general readers."— Jk'i/rA JifecManic,

THE HANDBOOK OF OPTICS. ByDiONYSius Lardner,D.C.L., formerly Professor of Natural Philosophy and Astronomy in UniTersiiy College, London. New Edition. Edited by T. Olver Harding, B.A. Lond., of University College, London. With 298 Illustrations. Small 8vo, 448 pages, 55. cloth.

" Written by one of the abk;st English scientific writers beautifully and elaborately {Dustrated." '—Mechanics' Magazine.

THE HANDBOOK OF ELECTRICITY, MAGNETISM, AND ACOUSTICS. By Dr. Lardner. New Edition. Edited by George Carey Foster, B.A., F.C S. With 400 Ilustrations. Small 8vo, 5s. cloth.

" The book could not have been entrusted to anyone better calculated to preserve tlic teisc and lucid style of Lardner, while correcting his errors and bringing up his work to the present state of cientinc knowledge."— yV/M/or Science Review.

Dr. Lfardner'8 Handbook of Astronomy.

THE HANDBOOK OF ASTRONOMY, Forming a Companion to the " Handbook of Natural Philosophy. By Dionysius Lardner, D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. Fourth Edition. Revised and Edited by Edwin Dunkin, F.R.A.S., Royal Observatory, Greenwich. With 38 Plates and upwards of zoo Woodcuts. In One Vol., small 8vo, 550 pages, 9s. 6d. cloth.

" Probably no other book contains the same amount of information in so compendious and - arranged a form— certainly nono at the price at which this is offered to the pubUc.'—j4tJuH€ti4m.

"We can do no other than pronounce this work a most valuable manual of astronomy, and wo strongly recommend it to all who wish to acquire a general— but at the same time correct— acquaint* ance with this sublime science."— <arfrr/y yournai Science.

"One 01 the most deservedly popukir books on the subject . . . We would recommend not only the student of the elementary principles of the science, but he who aims at mastering the hi;ncr and mathematical branches of astronomy, not to be witliout this work beside him."— /ractf cai .fajfOJiinf,

Natural Philosophy And Science.

Dr. Lardner'S Museum Of Scienge And Art.

THE MUSEUM OF SCIENCE AND ART. Edited by DiON'Ysius Lardnbr, D.C.Lm formerly Professor of Natural Philosophy and Astronomy in University College, London. With upwards of 1,200 Engravings on Wood. In 6 Double Volumes, £1 is., in a new and elegant cloth binding ; or handsomely bound in half-morocco, 3x5. 6d.

Contents :

The Planets: Are they Inhabited Worlds T— Weather Piwnostics — Popular Fallacies in Questions of Physical Science— Latitudes and Longitudes — Lunar Influences — Meteoric Stones and ShootincStars— Railway Accidents —Liifht— Common Things : Air— Locomotion in the United States— Cometary Influences- Common Things: Water— The Potter's Art— Common Tilings: Fire — Locomotion and Transport, their Influence and Progress— Th Moon — Common Things: The Earth— The Electric Telegraph — Terrestrial Heat — The Sun— Earthquakes and Volcanoes— Barometer, Safety Lamp, and Whitworth's Micrometric Apparatus— Steam— The Steam Engine— The Eye — The Atmosphere — Time — Common Tnings : Pumps — Common Things : Spectacle the Kaleidoscope — Clocks and Watches — Microscopic Drawing and Engraving- Loco-

motive — Theimometer — New Planets: Le- Terrier and Adams's Planet— Magnitude and Minuteness— Common Things: The Almanack —Optical Imafes— How to observe the Heavens — Common Things: The Looking-glass — Stellar Univcrso— The Tides— Colour— Common Thines: Man— Magnifying Glares- Instinct and IntelUgence— The Solar Microscope —The Camera Lucida— The Magic L.antcm— The Camera Obscura— The Microscope— The White Ants: Their Manners and Habits— The Surface of the Earth, er First Notions of Geography— Science and Poetry— The Bee — Steam Naviution — Electro-Motive Power — Thunder. Lightning, and the Aurora Borealis —The Printing Press— The Crust of the Earth —Comets— The Stereoscope— The Pre-Adamite Earth— Eclipses— Sound.

Opinions of the Press

" This scries, besides affording popular sound instruction on scientific subjects, with which the humblest man in the country ought to be acquainted, also undertakes that teaching of ' Common Things ' which every well-wisher of his kind is anxious to promote. Many thousand copies of this serviceable publication havo been printed, in the belief and hope that the desire for instruction ajul improvement widely prevails ; and we have no fear that such enlightened faith will meet with disappointment."— 7Ym/j.

" A cheap and interesting publ cation, alike informing and attractive. The papers combine subjects of importance and groat scientific knowledge consSderatile inductive powers* and a popular style of treatment."— /leetar.

"The 'Museum of Science and Art' Is the most valuable contribution that has ever been made to the Scientific Instruction of every class of society."— Sir DAVID BRUWSTBR, in the Aorth British RevUw.

" Whether we consider the liberality and beauty of the Illustrations, the charm of the writing, or the durable interest of the matter, wo must express our belief that there Is hardly to be foimd the new books one that would be welcomed by people of so many ages ana classes as a \uluable present."—

Separate books formed from the above, suitable for Workmen's Libraries,

Science Classes, &c.

Comm&n Things Explained, Containing Air, Earth, Fire, Water, Time, Man, the Eye, Locomotion, Colour, Clocks and Watches, ecc. 233 Illustrations, cloth gilt, 55.

The Mieroeeope* Containing Optical Images, Magnifying Glasses, Origin and Description of the Microscope, Microscopic Objects, the Solsu- Microscope, Microscopic Drawing and Engraving, ftc. 147 Illustrations, cloth gilt, 2S.

JPopular Geology. Containing Earthquakes and Volcanoes, the Crust of the Earth, &c. 201 Illustrations, cloth gilt, 2s. 6d.

Popular Bhyaic. Containing Magnitude and Minuteness, the Atmosphere, Meteoric Stones, Popular fallacies, Weather Prognostics, the Thermometer, the Barometer, Sound, &c. 85 Illustrations, clown gilt, %s. 6d,

Steam and its Usee. Including the Steam Engine, the Locomotive, and Steam Navigation. 89 Illustrations, cloth gilt, 25.

Pojndar Astronomjt* Containing How to observe the Heavens — The Earth, Sun, Moon, Planets, Light, Comets, Eclipses, Astronomicai Influences, &c. 182 Illustrations, 4s. 6d.

The Bee and White Ants : Their Manners and Habits. With Illustrations of Animsd Instinct and Intelligence. 135 Illustrations, cloth ilt, as.

TJte Electric Telegraph Popularised To render intelligible fo all who can Read, irrespective of any previous Scientific Acauirements, the various forms of Telegraphy in Actual Operation, xoo illustrations, cloth gilt, is.Gd,

14 Crosby Lockwood Co.'S Catalogue.

MATHEMATICS, QEOMBTRT, TABLES, etc.

Br€&ethical MathenuMcs.

MATHEMATICS FOR PRACTICAL MEN. Being a Common-place Book of Pnre and Mixed Mathematica. Designed chiefly for the Uie of Civil Engineers, Architecta, and Surveyors. Part I. Purs math- MATics : comprising Arithmetic, Algebra, Geometry, Mensuration, Trigonometry, Conic Sections, Properties of Curves. Part II. MixBD Mathxm ATXC8 : comprising Mechanics in general Statics, Dynamica, Hydrostatics, Hydrodynamics, Pneumatica Mechanical Agents, Streneth of Materials. Wim an Appendix of copious Logarithmic and other Tables. By Olintrus Grbo- ORY, LL.D.. F.R.A.S., Enlarged by Henry Law, C.E. 4th Edition, carefullT Revised by J. R. YouMO, formerly Professor of Mathematics, Belfast College. With 13 Plates, 8vo, £1 u. cloth.

"TlMcmeinMrorarcUtactiHIl hara tod ready to his hand fslet for MMng oMtly ewy mathamaticardUloilty that maj aria hi his pnctloe. The niles are in all cases ezplauiad by means of eTample in which araiy itep of tlw proceM is daily woilDad oaW—BuUtUr.

"One of the moat sanFlceabia books tot pncdcal mwrhanics. . . . Pntkmor Yoaag has moderebed the notadoa tlutmghoat; intvodttoea a Cbw paFSgiaphs here and there, and corrected the numerous trpofraphioai errors which liad escaped the eyes of tlie fonner Editor. The book it now as complete as it Is pomlMe to make it. It h an instinctive book for the student, and a Text-book for him who liaTinff once mastered the subjects it treats o4 needs occasionally to refresh his memory upon them—BuiicUtte New*,

"As a standard work on mathematics it has not bean exceOed."— rMnsM.

Metrical Units and SystemSf etc.

MODERN METROLOGY : A Manual of ths Mitncal Units and Systems of ths Present Century. With an Appendix containing a proposed English System. Bv Lowis D'A. Jackson, A.M. Inst. C.E., Author of Aid to survey Practice,' &c. Large crown 8vo, xss. 6i. doth.

The antlior lias brought togetlier much valuable and Interesting infbimatioa. . . . The main object of the work appears to be the dlscHssioa of a remedy for tlM evils of Uie complex systems of weigfats and mea wires width are nnfoctunately still in use in this countty. To provide such a remedy IS a serious taslc. and one wM worthy of the attention of a great statesman such as Mr. Gladstone to wluua the work is inscribed. . . . We cannot but recommend tlie work to the consideration of afl interested in the pnctical refoan of our weights and meesues."— isAtrv.

" For tlie paige collection of measures brought together, the uthor supplies the Frsncfa scientific equivalent in tenns of tlie melxical qrston. Hie also gives througliottt a double set of Engltsh equivalents the first of hldi he calls the 'Commercial Measurev end the second the ' Saentific Vahie.' . . . There is no doubt as to the great amount of labour that must have been devoted to the calculation ; and the Juxtaposition of the two vahaes aifords an ea means of checking the work by comparison."— /f/iAmsMfw.

For exhaosdve tables of equivalent welghta and measures of all sorts, and for dear demonstrations of the effects of the various systems uat have been proposed or adopted, Mr. Jacloon'a treatise is without a tinL'*-cad€>ny.

The Metric System.

A SERIES OF METRIC TABLES, in which ih$ British Standi ard Measures and Weights are compared with those of the Metric System at present in Use on the Continent. Bv C. H. Dowling, C.E. Second Edition, Revised and Enlarged. 8vo, los. 6a. strongly bound.

" Their accuracy has been certified by Professor Airy, the Astronomer-ReyaL"— Mr. Dowling's Tables, which are well put together, come Just in time as a ready-reckoner for the cooveision oiooe system into the —AtheHttum

Geometry for the Architect, Engineer, etc.

PRACTICAL GEOMETRY, for ths Architect, Enginar and Mechanic. Giving Rules for the Delineation and Application of various Geometrical Lines, Figures and Curves. Bv E. W. Tarn, M.A., Architect, Author of "The Science of Building," &c. Second Edition. With Appendices on Diagrams ot Strains and Isometrical Projection. With 172 Illustrations, demy 8vo, 95. cloth.

No book with the same objects in view has ever been published in whldi die denmess of the rnies laid down and the inustiatlve diagrams have been so satisftctofy.'*—

" This b a manual for the practical man, whether architect, engineer, or mechanic. . . . The object of the author being to avoid all abstruse formulse or complicated methods, #nd to enable persons with but a moderate knowledge of geometry to work out the problems required."— i?Mr/irA

MATHEMATICS, GEOMETRY, TABLES, $tc. 25

Comprehensive Weight Calculator.

THE WEIGHT CALCULATOR. Being a Series of Tables upon a New and Comprehensive Plan, exhibiting at One Reference the exact Value of any Weight from z lb. to z; tons* at 300 Progressive Rates, from id, to i68s. per cwt, and containing 286,000 Direct Answers, which, with their Combinations, consisting of a single addition (mostly to be performed at sight), will afford an aggregate of 10,266,000 Answers ; the whole being calculated and designed to ensure correctness and promote despatch. Bv Hbnry Harbbn, Accountant, Sheffield, Author of The Discount Guide.*' An entirely New Edition, carefully revised. Royal 8vo, strckngly half-bound, £1 su

"A ptscdcal and usefiil work of raferenoo for meii of buainen generally; It is the best of the kind we nave seea. WehaTe iireauently been asked if inch a work as this could be obtaine< therefore refer to It with pleasure. —/nmjiMn/Kr.

"Of prtoelew Talne to bnsiiiea mea. Its accmacy and complatenaM haye secured fbr It reputadoB which renders It quite unnecessary for us to say one word in its praise. It Is a neceanry took in aU mercantile oOe.'—SfiaUid ImdmdetU.

" An enoRBOus amount of labour must hafe been bestowed upon the preparation of the taUe but the result is a series which gives tlio answers sought more readily than any of its predecessors.

Comprehensive IHscount Ouide.

THE DISCOUNT GUIDE. Comprising several Series of Tables for the use of Merchants, Manufacturers. Ironmongers, and others, byr which may be ascertained the exact Profit arising from any mode of using Discounts, either in the Purchase or Sale of Goods, and the method of either Altering a Rate of Discount or Advancing a Price, so as to produce, by one operation, a sum that will realise any required profit after allowing one or more Discounts : to which are added Tables of Profit or Advance from to 90 per cent. Tables of Discount from to 9SI per cent., and Tables of Commission, ftc. from to zo per cent. By Hbnry Harbbn, Accountant, Author of " The Weight Calculator." New Edition, carefully Revised and Corrected. Demy 8vo, 544 pp. half-bound, £t 5s.

" AU these tables are well arranged and dearly printed ; and the collection will be found of great value in those businesses for which the book has been especially compOed."— J?ivbMrHU'

" A txMk such as this can only be appreciated by business men, to whom the saying of time means saving of money. We have the mgh authority of Professor T. R. Young that the tables throughout the work are constiuded upon strictly accurate prlndplea. The work Is a model of typographical clearness, and must prove of great vahie to merchants, manufacture, and general Inden, —BHHsM Tradt yumai,

"Much time and labour will be saved by the use of this bodk--<ien to the most expert arlthuaHdan. The great practical utility of the ' Discount Guide ' will no doubt make it a sundard work of reference."— /iMiuAm Comrtureial Rteord.

Iron and MetaZ Trades' Calculator,

THE IRON AND METAL TRADES* COMPANION. Being

a Calculator, containing a Series of Tables upon a New and Comprehensive

Plan, for expeditiously ascertaining the Value of any Goods bought or sold

by Weight, from is. per cwt. to xxas. per cwt., and from one fiulhing per

pound to one shilling per pound. Eacn Table extends from one pound to

200 tons. To which are appended Rules on Decimals, Square and Cube Root.

Mensuration of Superficies and Solids, Ac; also Tables of Weights ot

Materials, and other Useful Memoranda. By Tbouab Dowmijb. Strongly

bound in leather, 396 pp., 9s.

" A most useAil set of tables; and will supply a vraat for nothing Uke tfaani befora existed."' SniUing A'ews.

" Will save the possessor the trouble of making numerous Intricate cakulations. Although specially adapted to tho iron mad metal trades, the tables contained In this handy little companion wi I be found useful In every other business In which merchandise is bought and sold fcy weight."-' RaUvMy Newt,

JPractical Oeofnetry,

THE GEOMETRY OF COMPASSES; or, Problems Resolved

fy the mere Dncriptum Circles and the use of Coloured Diagrams and

Symbols. By Oliver . Coloured Plates. Crown 8vo, 3s. 64. cloth.

" A very useful work, which will be valued by afl who ai coming the useAd and study of geometry."— /riff.

"The treatise is a good one; and remarkable— Uke all Mr. Byrne's contributions to the science of geometry— for the lucid character of its teaching."— v/Af/v* .

" The problems in this usefttl book are cleverly worked out by beautifully coloured and uncoloured diagrams. It will no doubt be extensively circulated. We nhly recommend it."— CamtrUt

26 Crosby Lockwood Co.* S Catalogue

Industrial And Useful Arts.

Soap'fnakinff,

THE ART OF SOAP-MAKING : A Practical Handbook of the Manufacture of Hard and Soft Soaps, Toilet Soaps, &c. iDcludine many New Processes, and a Chapter on the Recovery of Glycerine from Waste Leys, By Alexander Watt. Author of " Electro- Metallurgy Practically Treated," &c. With numerous Illustrations. Crown 8vo, gs. cloth. " The work will prove vety useful not merely to the technological student but to the pnctscal

coapboilcr who wishes to understand the theory of his urt."—CAtmieai News.

" It is really an exceOent example of a technical manual, entering, as it does, thorooffhly and

exhaustively both into the theory and practice of soap manufacture. The book is well and noncstly

Uoue, and deserves the considerable orculation with which it will doubtless meet."— AfMw/apr. "Mr. Watt's book is a thorousrhly practical treatise on an art which lias almost no literature in

our lania. We conratuhite the author on the success of his ondeavour to fill a void in Englisli

te hnical hterature."— A a/Mf.

". . . . Clearly and concisely written, and appears to be comprehensive and complete"—

Leather Manufacture,

THE ART OF LEATHER MANUFACTURE, Being a Practical Handbook, in which the Operations of Tanning, Currying, and Leather Dressing are fully Described, and the Principles of Tanning Explained, and many Recent Processes introduced; as also Methods for the Estimation of Tannin, and a Description of the Arts of Glue Boiliog, Gut Dressing, &c. By Alexander Watt, Author of " Soap-Making.*' " Electro- Mctallurgy," &c. With numerous Illustrations. Crown 8vo, 125. bd. cloth.

\Jua published.

"Every item of use and interest to the leather trade has been touched upon, and descrii: and explanations of the various processes are exhaustively given."-— TanM/rx' attd Curriers

"A most lucid and readable book upon difficult and intricate subjects. Every known process tanning, from the most primitive to the most recent, is fully and accurately described."— ikvt/iji/i Leathtr Trader.

JBoot and Shoe Making*

THE ART OP BOOT AND SHOE-MAKING. A Practical Handbook, including Measurement, Last-Pitting, Cutting-Out, Closing and Making, with a Description of the most approved Machinery employed. By John B. Leno, late Editor of St. Crispin, and The Boot and Shoe-Maker. With numerous Illustrations. Crown 8vo, 5s. cloth. [Jms< published.

" A very complete account of the art and sdoicc of bootmaking, which includes all that need be said about leathers and other materials, as well as about hand-tools and the various machines tliat have latterly been introduced to supplement or supersede the old-fashioned handiwork."— Dis/a/Jk.

Dentistry*

MECHANICAL DENTISTRY: A Practical Treatise on the Construction of the various kinds of Artificial Dentures. Comprising also Useful Formula), Tables and Receipts for Gold Plate. Clasps, Solders, &c. &c. By Charles Hunter. Second Edition, Revisea. With upwards of 100 Wood Engravings. Crown 8vo, 7s. 6d. cloth. "The work is very practical."— Afdfi/Ay Revitw Denial Surgery.

" An authoritative treatise. . . . Wo can strongly recommend Mr. Hunter's treatise to all s preparing for the profession of dentistry, as well a yiturnal Medical Science.

students preparing for the profession of dentistry, as well as to every mechanical dentist. — Dublin

" A work in a concise form that few could read without gaining information from."— ri;ri;rA Journal nf Dental Science.

"The book on the subject with which we are acquainted."— J/ira/ Press and Circular.

live wing.

A HANDBOOK FOR YOUNG BREWERS. By Herbert

Edwards Wright, B.A. Crown 8vo, 3s. 6d. cloth.

" Thi little volume, containing such a large amount of food sense in so small a compd< ought to recommend itself to every brewery pupU, and many wno have passed that stage."— /-rri/rj,-' iinardiaH.

" The book is very clearly written, and the author has successfully brought his scientific know. ledge to bear upon the various processes and details of growing. To the young student of brewing the reading of such a book as this is calculated to do good, for it will lead him to inquire not on what is to be done, but why it should be done "—Brewer*

Industrial And Useful Arts. 27

Electroplating, etc,

ELECTROPLA TING : A Practical Handbook. By J. W. Urqu- HART, C.E. With numerous Illustrations. Crown 8vo, 55. cloth.

"The volume is withcnit a rJTal In Its particular sphere, and the lucid stvlo in which it is written couunends it to those amateurs and experimental electrotypers who have out slight. if any, knowledire of the oroecsses of the art to which they turn attention."— a$tdH'ork.

" The information given appears to be based on direct personal knowledge. ... Its science Is sound and the style is always <!cax'—Athen€eum.

Electrotyping etc.

ELECTROTYPING : Th$ Reproduction and Multiplication of Prints ing Surfaces and Works of Art by the Electro-deposition of Metals. By J. W. Urquhart, C.£. Crown 8vo, 5s. cloth.

" The book is so ihorouehly practical that it assumes to start with an entire i£norance on the reader's part of electricity. He is, therefore conducted through its leading laws, then through the inctals used by clectrotypera. the apparatus, and the depositing processes, up to the final preparation of the work."— yotirnal.

"In this work tlie author enters systeraaticany and thoroughly Into every department of the process, in the style of one who combines theory with practice, we can recommend this treatise, not merely to amateurs, but to those actually engaged m iho trade." — Chemical I\'rws.

Electric lAghting.

ELECTRIC LIGHT : Its Production and Use. Embodying Plain Directions for the Treatment of Voltaic Batteries, Electric Lamps, and Dynamo-Electric Machines. By J. W. Urquhart, C.E., Author of " Electroplating : A Practical Handbook.' Edited by F. C. Webb, M.I.C.E., M.S.T.E. Second Edition, revised, with large Additions and 128 litusts. 75. 6d. cloth.

" The book is by &r the best that we have yet met with on the subject."— w/AirMm.

"It is the only work at present available which gives, in language Intelligible for tlic roost part to the ordinary reader, a general but concise history of the means which stave been adopted up to the present time in producing the electric light. ... A chapter on the comparative cost of the electric light and gas contains much valuable and interesting infonnaiion.*— tow .

" The book contains a general account of the means adopted in producing the electric light, not only as obtained from voltaic or galvanic batteries, but treats at length of the dynamo-electric iiuichino in several of its forms. ... An addition to the literature of the electric, hfirht. Students of the subject should not fail to read W—CoUiery Guardian,

ELECTRO-METALLURGY : Practically TreaUd. By Alexander Watt, F.R,S.S.A. Eighth Edition, Revised, with Additional Matter and Illustrations, including the most recent Processes, izmo, 3s. 6d. cloth boards.

"From this book both amateur and artisan may learn evorytbinir nscettaiy for the successful prosecution of electroplating."— /rvw.

" A practical treatise for the use of those who admire to work in the art of electro- deposltioo as a hvsauasi.''— English Meckanic

Silveramiths' Work,

THE SILVERSMITH'S HANDBOOK. Containing full Instructions for the Alloying and Working of Silver, including the different modes of Refining and Melting the Metal, its Solders, the Preparation of Imitation Alloys, Methods of Manipulation, Prevention of Waste, Instructions for Improvmg and Finishing the Surface of the Work, together with other useful Information and Memoranda. By Gborob B. Gbe, Jeweller, &c. Second Edition, Revised, with numerous Illustrations, xamo, 35. 6d. cloth boards. { published.

"The chief merit of the work is its practical character. . . The workers Ut the trade will speedily discover its merits when they sit down to study it*'— English Afeckanic.

"This work forms a valuable sequel to the author's 'Goldanith's Handbook,' and supplies a want long felt in the silver Xxvid.'— Silversmith Trade Jountal,

Cldsmitlis' Work.

THE GOLDSMITH'S HANDBOOK. Containing full Instruc tions in the Art of Alloying, Melting, Reducing, Colouring, Collecting and Refining. The of Manipulation, Recovery of Waste, Chemical and Physical Properties of Gold, with a New System of Mixing its Alloys ; Solders, Enamels, and other useful Rules and Recipes, &c. By Gborob B. Gek. Second Edition, considerably enlarged. lamo, 35. td. cloth boards.

"A good, sound, technical educator, and will be generally accepted as an authority. It full particulars for mixing alloys and enamels, is essentially a book for the workshop, and exactly fulfils the purpose Intended."— //yvAvw*' y&umaL

"The work yet printed on tts subject for a reasonable price. We have no doubt that it will speedily become a standard book which fow wtU care to bo withoat."— yrwA'cr and Mttal yorker.

Crosby Lock Wood Co/S Catalogue.

Chemical Manufactures A Commerce.

Alkali TradBf Manufachi/te of StUphttrie Add, etc.

A MANUAL OF THE ALKALI TRADE, including the Manafactnre of Snlphnric Acid, Sulphate of Soda, and Eleachins Powdtf. Bt John Lomas, Alkali Manafacturer, Newcaatle-npon-Tyne ana London. With 233 lUnstrations and Workine Drawings, and containing 386 pages of Text. Saperoyai 8vo £z 12s, 6d. cloth.

Sulpni

This work provides (x) a Complete Handbook for intending Alkali and pnnric Acid Manufacturers, and fcM* those already in the field who desire to improve their plant, or to become practical] v acquainted with the latest processes anddevelopmentsof the trade: (a) a Handy Volume which Manufacturers can put into the hands of their Managers and Foremen as a useful guide in their daily rounds of duty.

Synopsit of CoMiets :

Chap. I. Choloe of Site ttid Ganenl Fba of Works.— II. Sulphuric Add.— III. Recoirery of the Nitrogen Compounds* md Treatment of Small Pyrttes.lV. Th6 Salt Cake Process.— V. Lceislation upon the Noxious Vapoun Question.—VI. The Uanmaves' and Jones' Processes.—VII. The BaDinff Process.— VIII. Lixlviaiion and Salting Down.— IX. Carbonating or

Finishing.— X. Soda Refined Alkali.— XII. Caustic SodaXIII. Biartxmate of Soda.-OCIV. Bleaching Powder.— XV. Utilisation of Tank Waste.— SCVl. Geneial Remarks—Four Appendices treating of Yields. Sulphuric Add Caiculatioo& Anemometers, and Forei LegUatioo upon the NoxioDS Vaponts Question*

" The author has given the ftiDest; moet practical, and. to all ooncemed in the aOcaB trade, most valuable mass of faiformation that, to our knowledge has been pubilsbed in any language."— irfif$eer.

"This book is written by a manufacturer for mannikcturan. The woricing delalli of the most approved forms of apparatus are given, and these are accompanied byno less than sm wood engravings, all of which may be used for the purposes of construction. Every step in tAe manufac lerc is very fully described in this manual, ana each bnprovement explained. Everything which tends to introduce economy ihto the technical details of this trade receives the fullest attention.*—

The author Is not one of those clever compiled who, on sheet notloei, wiU ' read op ' any coacdvable subject, ttut a practical man in the best senae of the word. We find here not merely a sound

aud luminous explanation of the chemical prindples of the trade, but a notice of numerous matters which have a most important bearing on the successful conduct of alkali woric but which are generally overlooked by even the most experienced technotoglcal authors."— CAtfmilai/ lUvtew.

Comtnercial Chemical Analysis.

THE COMMERCIAL HANDBOOK OF CHEMICAL AN- ALYSIS; or, Practical Instructions for the determination of the Intrinsic or Commercial Value of Substances used in Manufactures, in Trades, aod in the Arts. By A. Normandy. Author of "Practical Introduction to Rose's Chemistry," and Editor ot Rose's "Treatise on Chemical Analysis.*' New Edition, Enlarged and to a great extent re-written, by Hbnry M. Noad, Ph.D., F.R.S. With numerous Illustrations. Crown 8vo, 12s. 6d. cloth.

" We recommend this book to the careful perusal of everyone ; It may be truly affirmed to be of universal interest, and we strongly recommend it to our readers as guide alike indispensable to the housewife as to the pharmaceutical practitioner." — Mtdieat Times.

" Essential to the analysts appcted under the new Act. The most recent resolts are g1vel and the work is well edited and carefully written."— Abftnr.

lyyeWares and Colowrs.

THE MANUAL OF COLOURS AND DYE-WARES : Their Properties Applicationsaluationf Impurities, and Sophistications. For the ufe of Dyers, Printers, Drysalters, Brokers, &c. By J. W. Slatrr. Second Edition, Revised and greatly Enlarged. Crown 8vo, fOk 64. cloth.

This book contains a description of about Six Hundred Colours, Chemicals, and Drugs used in the Tinctorial Arts, and their Sources, Applications, and possible Impurities.

" A complete eacydopsdla of the materia titutaria. The information given respecting each article is full and precise, and the methods of determining the value of articles such as these, so lutblc to sophistication, are given with deamess, and are practical as well as valuable."— Olcm</

" Practical dyers, &C., will welcome the work in its improved form. There is no other work in the language which covers precisely the same ground. To technological students preparing for examinations bi dyeing sad printing u wO) prove exceedhigiy uaeltil."— CAMftaf/ Nnn, -

AdklCULTURE, LAND MANAGEMENt, etc. ig

AORIOULTURE, LAND MANAGEMENT, etc.

Youatt and Burn's Complete Oraaier.

THE COMPLETE GRAZIER, and FARMER'S and CATTLE- BREEDER'S ASSISTANT, A Compendiam of Husbandry; especially in the departments connected with the Breeding, Rearing, Feeding, and General Management of Stock ; the Management of tne Dairy, &c. With Direction for the Culture and Management of Grass Land, of Grain and Root Crops, the Arrangement of Farm Ofiices, the use of Implements and Machines, and on Draining, Irrigation. Warping, &c. ; and the Application and Relative Value of Manures. By William Youatt, Esq., V.S. Twelfth Edition, very considerably enlarged and brought up to the present requirements of Agricultural Practice by Robert Scott Burn, Author of " Outlines of Modern Farming," Landed Estates Management," "Farm Management," "The Lessons of My Farm," &c. One large 8vo Volume, 860 pp., with 244 Illustrations, £1 IS. half-bound. " The standard and text-book with the fanner and giazler."— AfrMwrj* MagoMine.

" A treatise which will remain standard work on the subject as Vaag as British affricujlure endures."— A/ar4 Latu Express (First Notice).

" The book deals with al departments of aericulture, and contains an Immense amount of valuable information. It is, in fact, an eacyclopseaia of agriculture put into readable ferui, and it is the only woric equally compreheosiTe brought down to present date. It is excellently printed ou thicic paper, and strongly txMind, and deserves a place in the library of ever>' agricultunst."— Ixuu Eatress (Second Notice).

Of great Taloe to the former, more especially to the y oong cattle breeder and feeder. . . . This esteemed work Is well worthy of a place In the libraries of agriculturists."— British AgricuUurisi.

"A valuable repertory of Intelligence for all who make agriculture a pursuit, and especially for thoee who aim at keeping pace with the improvements of the age. . . . The new matter is of so valuable a nature Uutt tne volume Is now almost entitled to be considered as a distinct work. '— BtU V Messatgvr,

Modem Famiinffm

OUTLINES OF MODERN FARMING. By R. Scott Burn. Soils, Manures, and Crops — Farming and Farming Economy — Cattle, Sheep, and Horses— Management of the Dairy, Piga and Poultry — Utilisation of Town-Sewage, Irrigation, &c. Sixth Eaition. In One Vol., 1,050 pp., halfbound, profusely Illustrated, 125.

"Theaimoftheaudiorhasbeento make his work at once comprehensive and trustworthy, and in this aim he has succeeded to a degree which entitles him to much cmUt,"— -Morning' Athftrtistrm

"Eminently calculated to enlighten the agricultural community on the varied subjects of it treati and hence it should find a place in every farmer's library."— Ciicx Press,

" No farmer should be without this book."— AMvnr Snardiem,

AgricultwriU Engineering*

The Complete Text-Book Of Farm Engineeb4Ng,

Comprising Practical Treatises on Draining and Embanking ; Irrigation and

Water Supply; Farm Roads, Fences, and Gates: Farm Buildings, Barn

Implements, and Machines ; Field Implements and Machines ; and Agziaul-

tural Surveying, Levelling, &c. By Prof. John Scott, Editor of the

Farmers* GaxetUf late Professor of Agricukure and Rural Economy at the

Royal Agricultural College, Cirencester, &c., Ac In One Vol., 1,150 pages,

wih 600 Illustrations, zas. half-bound. [yust published.

"Acopyof this work should be treasured up In every llbraiy where the owner thereof b in any way connected with land."— ,arm and Home.

" Written with great care, as well as with knowledge and ability. The author has done his work well ; we have found him a very trustworthy guide wherever we have tested hts statements. Tlie volume will of great value to agricultural students, and we have much pleasure in recomiiiCiKling it."— AforA Lane Express.

" For a young agriculturist we know of no handy volome so likely to be more usefully studied.* Be/rs tVeUly Musengtr.

Ainateur Farming*

THE LESSONS OF MY FARM: A Book for Amateur Agriculturists. Being an Introduction to Farm Practice. By Robert Scoct BuKK. With numerous Illustrations.

[A New and Enlarged Edition in preparation*

r

30 Crosby Lockwood Co/S Catalo6Vb.

A Text'Book of English Agriculture,

THE FIELDS OF GREAT BRITAIN : A Text-Book at

Agriculture, adapted to the Syllabus of the Science and Art Department.

For Elementary and Advanceid Students. By Hcoh Clbuknts (Board dt

Trade). x8mo, 25. 6d. cloth.

A most comprehensira Tolunie, glMnfr a mass of inromutioa."— .HltW/Mnt/ Eamvmist. " It Is a long Hme sinc we have seen a book which has pleased us more or which contains uch a rast and useftil fund of knowledge."— fdTiraxrna/ Times.

Agricultural Data*

NOTE BOOK of AGRICULTURAL FACTS and FIGURES, for Farmen and Farm Students, By Primrose McConnell, Fellow of the Highland and Agricultural Society* late Professor of Agriculture, Glasgow Veterinary College. Royal 33mo oolong, leather, with strap, 4s.

" It is full of very valuable Infennation. Fanners' sons and ether youths who wish to become farmers at home or abroad, miffht, even before their school education is completed, become familiar with the facts and figures furnished in this interesting and valuable little book."— herdten Free Press.

Hudson's Land Valuer's JPocket-Book,

THE LAND VALUER'S BEST ASSISTANT: Being Tables on a very much Improved Plan, for Calcnlatin|; die Value of Estates. With Tables for reducing Scotch, Irish, and Provincial Customary Acres to Statute Measure, &c. By K. Hudson, C.B. New Edition. Royal 32mo, leather, gilt edges, elastic band, 45.

"This new edition includes tables for ascertaining the value of leases for any tern of years ; and for showing how to lay out plots of ground of certain acres In forms, square, round. &c., with valuable rules for ascertaining the probable worth of standing timber to any amount ; and Is of incalculable value to the country gentleman and professional maa."—iFarmers l/aura/,

JBkvart's Land Improver's JPocketBook,

THE LAND IMPROVER'S POCKET-BOOK OF FORMULA, TABLES and MEMORANDA required in any Computation relating to the Permanent Improvement 0/ Landed Property. Bv John Ewart, Land Surveyor and Agricultural Engineer. Royal szmo, oblong, leather, gilt edges, with elastiis band, 45. A compendious and handy little volume."—

Complete Agricultural Surveyor's Bocket-Book*

THE LAND VALUER'S AND LAND IMPROVEIS COM- PLETE POCKET-BOOK. Consisting of the above Two Works bound together. Leather, gilt edges, with strap, 73. 6d.

" We consider Hudson's book to be the best on matters refaiting to the valua> tion of land and crops we have ever sees, and its combination with Mr. Ewait's work greatly enhances the value and usefulness of the latter-mentioned. ... It is most useful as a manual for reference." — North <ff England Farmer.

Potato Culture.

POTATOES : How to Grow and Show them, A Practical Guide to

the Cultivation and General Treatment of the Potato. By James Pink.

With Illustrations. Second Edition. Crown 8vo, as. cloth.

"A well- written little volume. The author gives good practical instructions under both diviuoiis of bis subiczW—jIgrun/tural Gaette.

QARDENING, FLORICULTURE, etc.

Early Fruits Flowers and Vegetables.

THE FORCING GARDEN : or, How to Grow Early Fruits, Flowers, and Vegetables. With Plans, and Estimates for Building Glass* houses. Pits and Frames. Containing also Original Plans for Double Glazing, a New Method of Growing the Gooseberry under Glass, &c.. &c., and on Ventilation, Protecting Vine Borders, &c. With Illustrations. By Samuel Wood. Crown 8vo, 35. 6a. cloth.

" A good book, and fairly fills a place that was in some degree vacant. The book Is written iih great care, and contains a great aeal of valuable teaching." — Gardeners' Maaxine,

" Mr. Wood's book is an original and exhaustive answer to the question 'How to Grow Early Fruits, Mowers and Vegetables?'"— /.tfrfiT/irf IVater.

GARDENING, FLORICULTURE, etc. 31

Good Garilening*

A PLAIN GUIDE TO GOOD GARDENING or. How to Grow Vegetables, Fruits, and Flowers. With Practical Notes on Soils, Manures, Seeds, Planting. Layin|;-out of Gardens and Grounds, &c. By S. Wood. With numerous Illustrations. Third Edition. Crown 8vo, 5s. cloth.

" A rery stood book, and one to be highly recommended as a practical guide. The practical directions are excellent." — AtJutueum,

" May be recommended to young gardeners, cottagers, and specially to amateurs, for the plain, rimple, and trustworthy jofonnation it gires on common matters too often neglected."—

Gainful Gardening.

MULTUM-IN-PARVO GARDENING; or, How to make One Acre of Land produce £620 a-;ear by the Cultivation of Fruits and Vegetables ; also. How to Grow Flowers m Three Glass Houses, so as to realise £176 per annum clear Profit. By Samuel Wood, Author of Good Gardening," <Kc. Fourth Edition, revised. With Wood Engravings. Crown 8vo, 2s. cloth.

" We are bound to recommend It as not only suited to the case of the amateur and gentluuin's gardener, but to the market grower.''—Card*' Afagturitu.

" Of all the practical guides to the amateur, as well as betnglnTahiable to most gardeners, Mr Wood's book is the most accurate and condsc'—HprtiatifuradJitconl,

Gardening for Ixidies.

THE LADIES' MULTUM-IN-PARVO FLOWER GARDEN, and Amateur's Complete Guide, With Illustrations. By Samusl Wood. Crown 8vo, 35. 6d, cloth.

" This volume contains a good deal of sound, common-sense Instruction."— Fififr///. Fun of shrewd hints and useful instructions, based on a lifetime of experience."— 5a>/jma//. ]

Receipts for Gardeners*

GARDEN RECEIPTS. Edited by Charles W. Quin. i2mo, IS. 6d cloth limp. "A useful and handy book, containing a good deal of valuable Information."— /f£A;iarf/m.

Kitchen Gardening.

THE KITCHEN AND MARKET GARDEN, By Contributors to " The Garden.** Compiled by C. W. Shaw, Editor of Gardening 111 us* trated." xamo, 3s. Gd. clown boards. " The most valuable compendium of kitchen and market-garden work published."— Farwrr.

Cottage Gardening.

COTTAGE GARDENING; or. Flowers, Fruits, and VegetabUs for Small Gardens. By E. Hobday, xamo, is. 6d, cloth limp. " Definite instructions as to the cultivation of small gardens."— Atfrma. "Contains much useful information at a small charge."— Herald,

AUCTIONEERING, ESTATIC AGENCY, eto. Auctioneer's Assistant.

THE APPRAISER, A UCTIONEER, BROKER, HOUSE AND ESTATE AGENT AND VALUER'S POCKET ASSISTANT, for the Valuation for Purchase, Sale, or Renewal of Leases, Annuities and Reversions, and of property generally; with Prices for Inventories, &c. By Johm Whbbler, Valuer, &c. Fifth Edition, R&> written and greatly Extended by C. NoRRib, Surveyor, Valuer, &c Royal 3amo, 5s. cloth.

" A neat and concise book of reference, containing an admirable and dearly-arranged Hsl of prices for inventories, and averypracticalguidetodeterminethe value of furniture, &c." — ittamtani

" Cram full of valuable information of practical value. It is a trustworthy and comiwndious tpiide to all sorts of valuation."— jljent.

Auctioneering.

AUCTIONEERS: Their Duties and Liabilities, By Robert Squibbs, Auctioneer. Demy 8vo, xos. 6d. cloth.

The position and duties of auctioneets are treated compendiously and dearly."— A'iy.frr. Every auctioneer ought to possess a copy of this excellent work."— /rwuMwivvr. Of great value to the profession. ... We readily welcome this book."— fiAiAx GucMfc

ri

32 CkdsB LOCkiVoot) cs* C6.*s CatalogV,

House Property.

HANDBOOK OF HOUSE PROPERTY : A Popular and Practical Guide to tfu Purchaut Mortgage, Tenancy , and Compulsory Sale of Houses and Land, By B. L. Tarbuck, Architect and Surveyor. Third Edition, xzmo, 35. 6d. cloth.

" The advice b thoroughly pnctlcaL*— Zow ytumaL

" This b a well-written and thoafirhtftd work. We conunend the work to the caiefitl stir of all interested fn questions airM:ting houses and land £aM/ Agait HecortL

Inwood's Estate Tables*

TABLES FOR THE PURCHASING OF ESTATES, Freehold, CopyMldor Leasehold; Annuities, A dvowsons,&c., Bad for the Renewing of Leases held under Cathedral Churches, Colleges, or other Corporate bodies, for Terms of Years certain, and for Lives : also for Valuing Reversionary Estates, Deferred Annuities, Next Presentations, Sec: together with Smart's Five Tables of Compound Interest, and an Extension of the same to Lower and Intermediate Rates. By W. Imwood. 22nd Edition, with considerable Additions, and new and valuable Tables of Logarithms for the more Difficult Computations of the Interest of Mone;y, Discount, Annuities, Ac., by M. Fbdor Thouan, of the Socitft Cridit Mobiher of Paris, xamo, 85. cloth.

"Those Interested In the purchase and sale of estate and In the adjustment of compensation cases, as well as in transactions in annuities, life insttcanceik Acc wUl find the present edition of eminent senrice."— fiVMrrt/i.

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