The geology of the South Wales Coal-field (Memoirs of the Geological Survey. England and Wales)

E.G Radley · 1908 · Historical

PREPARATIONS for this Memoir on the Coals ot South Wales were commenced in 1901, when Sir Archibald Geikie was Director-General of the Geological Survey

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Memoirs Of The Geological Survey

England And Wales.

The Coals Of South Wales

With Special Reference To

The Origin And Distribution Of Anthracite.

By AUBREY STRAHAN, M.A., Sc.D., F.RS., F.GS., ann W. POLLARD, M.A, DSe., F.G.S.

Assistep By E. G. RADLEY.

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Preface,

PREPARATIONS for this Memoir on the Coals ot South Wales were commenced in 1901, when Sir Archibald Geikie was Director-General of the Geological Survey, and the collection of material has proceeded since that date, as circumstances allowed. Though obviously incomplete, in the sense that analyses might be multiplied indefinitely, the work had so far progressed in 1907 as to lead to a more or less definite opinion as to the relative distribution of anthracitic and bituminous coals, and as to the origin of the difference between them, The time appeared, therefore, to have arrived for publication of the results, though admittedly a larger number of analyses would add precision to the generalisations, and illustrate more fully certain seams and certain parts of the coalfield.

Necessarily there was much doubt at its inception what form the investigation should take. That each seam should be examined separately, and its modifications traced step by step from the bituminous into the anthracitic region, was clear. It was desirable also that all analyses should be made ona uniform system. Jor various reasons, explained in the following pages, it was impossible to follow fully so ideal a scheme. Samples of coal were not always procurable from the desired seam or locality, while a large number of analyses, the accuracy of which there was no reason to doubt, would have been inadmissible. Eventually it was decided that while special attention was being devoted to certain seams, opportunities ought not to be lost of getting specimens of others which happened to be accessible.

Difficulty arose also from the natural reluctance of the colliery proprietors to consent to the publication of coal-analyses over which they had had no control. This was overcome by the assistance kindly rendered by the South Wales Institute of Engineers. Not only was an arrangement made with the proprietors under which specimens could be collected and analyses published, but through Mr. Jones Price, Secretary to the Institute, we were kept informed where specimens could be procured.

This volume, which is the outcome of the investigation, has been written by Dr, Strahan and Dr, Pollard. The latter, with

the assistance of Mr. E, G. Radley, has carried out all the chemical work, except some analyses which were made for the Geological Survey by Mr. C. A. Seyler. To Dr. Pollard also are due the chapters dealing with the methods of analysis, possible causes of error in analysis, and the classification of coals. The relation of carbon to hydrogen having proved to be the most reliable factor for expressing the character of the coal as regards anthracitism, the series of maps (forming Plates 3-7) were prepared to illustrate the distribution of anthracite on this basis. So far as we are aware, this is the first attempt to define the distribution of anthracite on purely experimental data.

Our thanks are due to Mr. Seyler for much assistance. He has not only furnished us with a large number of analyses, made independently of this investigation, but has given advice of great value in deciding on the method of analysis. We have also had the benefit of his comments on this volume during its passage through the press.

J. J. H. TEALL, Director. Geological Survey Office, 28, Jermyn Street, London, 17th February, 1908,

CONTENTS. PAGE PREFACE by the Direcror... ae hie ie a iil. CuaprTer |.—Historical and Tueroduetory y oe ae a Eas 1 CHAPTER II.—Sequence of the Coal-seams ... a 4 Cuarter ITI.—Analytical Methods and Table of Evnlpsess: ae 6 Cuaprer [V.—Accuracy of Coal Analyses... 28 CuHaAptTerR V.—Comparison of different bands of the same ee and Comparison of different Samples from the same Seam in the same Locality we 38 Cuapter VI.—Comparison of different Seams in ne same Teele 43 Cuaprer VII.—Classification of Coals . a 48 CuaptTer VITI.—Explanation of the Tso" nathincitic Char te. (Plates 3 to 7) eee wee eee tee eee eee 55 CHAPTER [X.— Origin of (eceeen ade st si a ne 63 INDEX... ne ae ine Ste ss me a ae me is ILLUSTRATIONS.

Plate 1.—-Map of the South Wales Coalfleld, showing Railways and Positions of Analyses.

Plate 2.—Comparative Sections of the Coal Measures of South Wales, showing the Position and Correlation of Coal-seams.

Plate 3.—Map of the South Wales Coalfield, showing Iso-anthracitic Lines in the Seams below the Ras-las Vein.

Plate 4—Map of the South Wales Coalfield, showing Iso-anthracitic Lines in the Ras-las, Nine Feet or Stanllyd Vein.

Plate 5.—Map of the South Wales Coalfield, showing Iso-anthracitic Lines in the Veins between the Ras-las and the No. 2 Rhondda Veins.

Plate 6.—Map of the South Wales Coalfield, showing Iso- anthracitic Lines in the No. 2 Rhondda and Hughes Veins.

Plate 7.—Map of the South Wales Coalfield, showing Iso-anthracitic Lines in the Mynyddislwyn, Swansea Four Feet, and Swansea Six Feet (Graigola) Veins.

Plate 8.—To show the rate of the change in anthracitic character from South to North in the Swansea Five Feet Vein.

Plate 9.—To show the percentage of ash increasing with the bituminous constituent.

Plate 10.—Map of the South Wales Coalfield, showing Positions of Measurements of Strata.

10163, 750 Wt.—22073 5.08 Wy. &S.

The Coals Of South Wales

With Special Reference To

The Origin And Distribution Of Anthracite.

Chapter I.

HisroricaL AND InrRopucTory, By A. Srranan.

THE existence of anthracite in the South Wales coalfield was well known to the earliest miners of whom records exist, and the part of the coalfield to which anthracite was limited was roughly defined, so far as regards the small depths they were able to attain. Leland, for example, mentions that the coals of the Gwendraeth-fawr are anthracite (stone coals), while those of Llanelly are bituminous (ring coals).* The development of the coalfield, however, during the last 100 years has added much to the superficial observations first made, and has shown that the gradation into anthracite proceeds in accordance with certain general laws, the investigation of which seems likely to lead to results of both scientific and economic value.

The changes undergone by the coal present certain stages, which, though recognised commercially, are not capable of exact definition: from house-coal, or the most bituminous, the change is gradual into steam-coal, and from steam-coal into anthracite. The facts reported with respect to the changes are as follows :—

1st.—The anthracitic regions lie in the north-western corner of the Carmarthenshire, Brecknock, and Glamorganshire field, and in Pembrokeshire. In the former, which we may call the main coalfield, the seams become gradually less bituminous in approaching the anthracitic region. The change takes place

*"At LLanelthle, a Village of Kidwelli Lordship, a. vi. miles from Kidwell, th Inhabitans digge Coles, elles scant in Kidwelly Land, Ther be ii. Maner of thes Coles. Ring Coles for Smith be blowid and waterid. Stones Cole be sumtime waterid, but never blown. For blowing extinguishit them. So that Vendwith Vaur Coles be Stone Coles ; LLanethle Coles Ring Colis."

("The Itinerary of John Leland the Antiquary," vol. 5. Published from the original Ms. in the Bodleian Library, by Thomas Hearne, M.A., Oxford, 1744.)

2 The Coals Of South Wales.

from east to west along the north crop in the eastern end of the coalfield, from south-east to north-west nearer to Cardiff, and from south to north near Swansea and in the western art of the main coalfierd. In other words, lines of equal anthracitisation circle round an area which extends from Kidwelly to Glyn Neath. In Pembrokeshire all the coal is anthracitie.

2nd.—The seams all show the change on approaching the anthracitic region, but the higher seams. show it later than the lower. Thus No. 2 Rhondda Coal keeps its character as a house-coal to within about 25 miles of the anthracite centre, and then becomes a steam-coal. The house-coals, about 400 yards below, become steam-coals about 30 or 40 miles from the anthracitic centre, and then occur as anthracite for a distance of about 25 miles. It follows that in any one deep shaft the shallower seams should be more bituminous than the deeper, which as a fact has been proved to be generally the case.

3rdly.—The loss of bituminous matter takes place at a more rapid rate in a south-to-north direction than in an east-to-west direction, This fact, taken in connection with the general form of the anthracitic region, so far as it has survived denudation, indicates that the original area of anthracitic coal was elongated in an east-and-west direction. It is obvious, moreover, that that area did not even approximately coincide with the existing coalfield, but lay, for the most part, outside it to the north and north-west.

There have been many speculations on the reasons for the diminution in bituminous matter. But while it was easy to find serious objection to every theory that has been advanced, the facts were not sufficiently definite to enable any fresh hypothesis to be put forward with confidence. A large number of analyses had been made, partly in connection with an official report written in 1848 by De la Beche and Playfair on "Coals suited to the Steam Navy," and partly for Dr. Percy for the purposes of his work on " Metallurgy." Of later years man aiateee had been arried out by Mr. C, A. Seyler, to whom is due the credit of having taken the first steps towards a systematic classification of South Wales coals. Many others also had been furnished to colliery-proprietors by various analysts, but of these several were useless for the present purpose, some because the name of the seam was not given, tHe inasmuch as they were only proximate. Finally, a large series of analyses, including many of South Wales, had been collected in a useful publication by the Colliery Guardian Corpany.

_[t was clearly desirable, however, for the special purpose in view, that not only should all available artist ses be collected and compared, but that all should be referred to their proper horizons in the Coal Measures, and that the series should be supplemented when necessary for the investigation of the change in character of any particular seam, Arrangements were commenced for the collecting and analysing of such further samples

Introductory. 33

as might be required in January, 1901, by the sanction of Sir A. Geikie, at that time Director-General of the Geological Survey.

In view of the difficulty of knowing where a seam of which a specimen was required was at the moment being worked, and of obtaining the consent of the colliery-proprietors to fresh analyses being published, the advice of the South Wales Institute of Engineers was sought, with the result that on the 14th of January the Council appointed a Committee of the following gentlemen as being representative of every part of the coalfield :—The President (Mr. Thomas Evens), Messrs. Archibald Hood, H. K. Jordan, H. W. Martin, W. D. Wight, John Roberts, Hugh Bramwell, Fox Tallis, W. Stewart, W. Forster Brown, James Barrow. Eventually the task of ascertaining in what. localities specimens could be obtained, and of communicating with the Prins: prietors, fell to the Secretary of the Institute, Mr. T. Jones Price, whose cordial co-operation in the work proved to be invaluable. It was arranged with the colliery-proprietors that the analyses might be published, but that the localities from which the samples were obtained should be indicated by numbers only on a

eneral map of the coalfield, and that the names of the collieries should not be mentioned. These conditions have been complied with.

In selecting specimens with the special object in view of illustrating the progress of the change in the composition of the coal, it was obviously advisable to deal with each seam separately. It was useless, for example, to compare a seam high up in the Coal Measures in one locality with a seam near the base of the Coal Measures elsewhere. Specimens from the same seam, on the other hand, would be comparable in different localities, though they might be obtained from different depths below the surface. It seemed to be advisable, therefore, to select for the investigation a few of the more important seams, and especially those which could be recognised over wide areas. Subsequently difficulties arose in consequence of the selected seams not being accessible in regions from which specimens were desired, and from other causes, while at the same time, from a rigid adherence to this scheme, opportunities of getting specimens from other seams would have been lost. The bulk of the published analyses, moreover, could not have been utilised. hile, therefore, the desirability of obtaining a series ef analyses illustrative of the changes in any one seam was not lost ae of, analyses of other coals of local importance have been included in the lists.

The collecting was commenced in 1901. It was arranged that the collector should be conducted, at every colliery he visited, to a working face where a typical development of the seam was exhibited, and that coal should be cut by an official of the colliery from all parts of the face, except those partings which are separated out i the miners. The coal thus cut was sampled by the collector in the usual manner, and the sample was enclosed in a box with a printed form filled in by the colliery-manager, on which were given the name and section of the seam, depth from surface, and other particulars.

Chapter Ji.

SEQUENCE OF THE SEAMS. By A. STRAHAN.

In view of the importance of considering the analyses of each seam separately, it becomes necessary to correlate, as far as possible, the seams of one part of the coalfield with those of another. In Plate 2 a series of vertical sections ranging from the east to the west end of the coaltield, is arranged with the principal seam of the most productive belt of the measures as a datum-line. Above and below the datum-line the various seams referred to in the table of analyses are inserted in their proper respective positions, but the table does not profess to give a complete list of all the seams known to occur in South Vales.

The recognition of the seam selected as a datum-line may be regarded as fairly certain from Pontypool westwards so far as the Neath Valley along the North Crop. Its identification as the Nine Foot near Aberavan in the South Crop, and as the Stanllyd or Big Vein in the more western sections, is open to doubt. But though individual seams are difficult to ic entify, the productive belt as a whole is easily recognised. The identifjcation of the principal seam in this belt as one and the same seam, while aaimsitiadly unproved, is put forward as the most probable, and as being certainly not far from the truth. The analyses of the seam thus selected are inserted on the map forming Plate 4,

No individual correlation of the seams below the datum-line has been attempted. Local y some of them are valuable, but no one of them can be traced continuously over more than a small part of the coalfield. The analyses of these coals are grouped together in the map forming Plate 3.

The group of veins shown close above the datum-line in the four right-hand columns of Plate 2 yield the bulk of the best smokeless steam-coal of Glamorganshire, From Pontypool to the Neath Valle they are individually recognisable along the northern and central parts of the coalfield. West of that valley and in the South Crop the seams in a corresponding position change greatly in number and thickness, and no correlation of individual seams has been attempted. The analyses of the veins belonging to this horizon are presented in the map forming Plate 5. .

The identification of the seam known as the Tillery Vein in Monmouthshire, with that known as the No. 2 Rhendds Seam

Sequence Of The Seams. 5

in Glamorganshire, and by other names in various parts of the coalfield, has been discussed in every succeeding Part of the Memoir on the South Wales Coalfield, and needs no further comment here. The analyses are shown on Plate 6.

The correlation of the Mynyddislwyn Vein with the Llantwit No. 3, the Wernffraith or Swansea Four Feet and the Box Bio of Llanelly, is less capable of proof. Its correlation with the Llantwit No. 3 has been adopted in accordance with arguments brought forward by Mr. H. K. Jordan* in preference to the correlation with Llantwit No. 1 which was originally selected. The reasons for identifying Llantwit No. 3 with the Wernffraith or Swansea Four Feet vein are explained in "The Country around Swansea" (Mem. Geol. Survey), 1907, pp. 33-35, but by some authorities the Graigola Vein of Swansea is reyarded ag the equivalent of the Mynyddislwyn. That the Wernftraith., Swansea Four Feet and Box Big are one and the game vein is generally admitted. The analyses of the Mynyddislwyn Vein and its supposed equivalents are inserted in Plate 7, together with those of some of the veins which occur between it and the "No. 2 Rhondda seam.

Two facts are illustrated by the series of sections forming Plate 2. Firstly, that the measures expand rapidly from east to west, the thickness intervening between the Mynyddislwyn and the lowest seam at Pontypool being little more than a quarter of the thickness between the Box Big and the lowest seam near Llanelly. Secondly, that an expansion takes place also from north to south, the thickness near Aberavan in the South Crop being considerably greater than that in the North Crop on the same line of longitude. One exception to this rule is to be observed: locally, near Pontypool, there is a southerly and easterly attenuation, the smallest thickness known in any part of the coalfield being found near Cwm Bran. The greatest thickness on the other hand is reached in the south-west part of the coalfield, where no less than 5,700 feet intervene between the Box Big and the datum-line. Whether there is any connection between the varying thickness of the measures and the anthracitic character of the coal will be discussed in Chapter IX.

Proc. S. Wales Inst. Eng., vol. xxiii (1903), pp. 190-204, 323-337.

CHAPTER ITI. ANALYTICAL MeTHops AND TABLE OF ANALYSES. By W. Poutarp.

Tue methods of analysis employed for those analyses made in the Geological Survey Laboratory are given rather fully, as it is well known that variation in method in coal-analysis (especially in the determination of volatile matter) may produce variation in results. For the most part the methods are practically the same as those recommended by the Commission on Coal-analysis of the American Chemical Society.*

Sampling.—The samples as received at the laboratory are packed in large biscuit-tins enclosed in wooden boxes. The weight of the sample is 20 to 30 lbs. Usually it contains no large pieces, but all larger than a small orange are broken ae the whole sample passed through a 1-in. sieve. After eee mixing it is quartered in the usual way, the rejected half being at once replaced in the tin, whilst the other half is passed through a small Marsden-Blake crusher, and reduced by quartering to about 1 Ib. This is then ground in a coffee-mill, set fine, halved and transferred to two-stoppered bottles, the one for analysis, the other being tied down and sealed, in case it be required for future reference, The sample obtained by grinding in the coffee-muill is used for moisture and volatile matter estimations. For all other estimations a portion of this is further ground to pass the 50-hole sieve, the moisture is separately estimated in this sample also, so that all estimations can be calculated on coal as received. When coal-analysis was first started in this laboratory volatile matter was determined on both samples, but as in no case were any great differences found, the determination on the fine (50-hole) sample was discontinued.

For the estimation of specific gravity a special sample is taken from the tin, and that portion only is used which passes an 8-hole and is retained on a 16-hole sieve. Moisture and ash are separately estimated on this sample in order to get the density of the dry coal, and an approximation to that of the pure coal.

Moistwre.—This is estimated in all three samples. One rramme of coal is heated in a Victor-Meyer toluene bath for one 1our exactly, The coal is weighed off between clipped watchglasses, heated uncovered, covered immediately on removal from the toluene bath, and allowed to cool in a desiccator. It is weighed half an hour after removal from the bath. This method has been used in preference to that of drying in vacuo with sulphuric acid in a Hempel desiccator, as it 1s believed to be

Jown. Am. Chem. Soc., 1899, vol. xxi, p. 1,116.

ANALYTICAL METHODS. ik

the more generally in use in other laboratories, althoueh in many cases less moisture is found by this method. A discusdion on this point is to be found in the Jowrn. Am. Chem, Soe. (loc. ert.).

Duplicate estimations should agree within '1 per cent.

Volatile Matier—One gramme of coal is heated for seven minutes exactly in a platinum-crucible with well-fitting cover supported on a platinum-triangle over a bunsen giving a flame 20 cm. high. The bottom of the crucible should be 8 em. above the mouth of the burner; gas-pressure should be 50 mm. of water. The particulars of the crucible used are :—Height, 40 mm. ; diam. at base 24 mm., at top 834 mm. Capsule cover. A cylinder of clay or asbestos-board (of about 12 cm. diam.) should be used to prevent draughts from influencing the flame during the operation.

Loss in weight minus moisture gives volatile matter,

Duplicates should agree within '15 per cent. on coals, with 15 per cent. volatile matter and under, and '30 per cent. on coals with over 15 per cent.

The value found for volatile matter depends to some extent on the size of crucible, tightness of cover, strength of flame, &c.; it is of importance therefore to work under as constant conditions as possible. With some coals at times a small explosion occurs after about one minute's heating, in which case the experiment should be discarded, otherwise too much volatile matter will be found. The cover of the crucible should fit so as to allow the egress of the volatile matter as easily as possible, but prevent the air from getting at the coke more than can be prevented. Meade and Attix* suggested heating a second time under identical conditions and subtracting the second loss from the first. This was tried in several cases, but did not appear to offer any distinct advantage over the other method.

Ash.—(See also under "Combustion.") The ash left in the platinum-boat after combustion has invariably been taken as representing the ash in the coal. Of all the constituents ash is probably the least accurately determinable (and hence oxygen also), a point that is gone into under "Accuracy of Coal Analyses" on page 29.

Duplicates should agree within '1 per cent. on coals with less than 4 per cent. ash, and '2 per cent. on coals with more than 4 per cent. ash.

Fixed Carbonaceous Residue.—tThis is obtained by subtracting the sum of the percentages of ash, moisture, and volatile matter from 100.

Jownn. Am, Chem. Soc., 1899, vol. xxi, p. 1,137,

8 The Coals Of South Wales.

Total Sulphur.—The method of-M. W. & J. Atkinson has been used with only slight modification. The following description of the method is taken from the report of the Commission on Coal Analysis of the American Chemical Society.*

"One gramme of finely-ground coke or coal is mixed thoroughly with 5 grammes of dry sodium carbonate, spread evenly over the bottom of a flat or shallow platinum dish, and the latter placed on a rectangular rest made of clay pipe-stems inside a muftle, which though hot is still black. The temperature of the muftle should be raised gradually during half an hour to clear cherry-redness, and then kept at the latter temperature for 10 to 15 minutes. The sodium carbonate should not sinter or fuse. The mass should not be stirred. When the carbon is burned, usually in about 45 minutes in all, cool, digest with 100 to 200 c.c, of warm water, allow to settle, decant through a filter and wash twice by decantation, and then on the tilter, adding a few drops of a solution of sodium chloride if the residue tends to pass through the filter. The filtrate is acidified with 12 cc. concentrated hydrochloric acid, and precipitated with barium chloride."

To aveid any possibility of all the sulphur not being oxidised to sulphate before acidifying, a little (about 10 ¢@c.) bromine water bie always been peek after filtering and before acidifying. It is usually necessary to heat for longer than the 45 minutes to burn off all the carbon. With these slight differences the method has been adhered to with most satisfactory results. The muftes used have been Fletcher gas-muties, Nos. 461 and 661. Blind experiments have always been made simultaneously with and separately from determinations of sulphur in coal, and in no case has any appreciable amount of sulphur been obtained from the gas. As it is almost invariably necessary to correct for traces of sulphur contained in the sodium carbonate used, it is always as well to make a blind experiment with each batch of sulphur-estimations.

Duplicates should agree within per cent,

Sulphur in Ash —This is obtained from the ash from the combustion. The ash is transferred to a dish, hydrochlorie acid added, evaporated to dryness, taken up with hydrochloric acid and hot water, filtered, and the sulphur in the filtrate precipitated with barium chloride. The amount of sulphur obtained here, subtracted from the total sulphur, gives the Combustible Sulphur,

Nitrogen.—Kstimated by Kjeldahl's method. 1 gramme of coal is heated with 20 ce. strong sulphuric acid, 8 grammes dry potassium sulphate and a bead of mercury, till colourless. Allow to cool, pour into a flask of about 1,000 ¢.c. capacity containing about 200 c.c. water, rinse out, ete, and add 80 ce. of a 50 per cent. sodium hydrate solution and 20 ee. of a 5 per cent,

Analytical Metiiods, 9

potassium sulphide solution. Distil (using a good splash-head),

'ion, Tite. ee sn ph: collecting in 20 c.c. 10 acid. Titrate back with jo wkali, using methyl orange as indicator,

The mercury, and hence the potassium sulphide, may be dispensed with,* the only difference apparently being that with the mercury shorter heating is needed. Blind experiments should be made and the correction apphed. Duplicates should agree within '1 per cent,

Combustion.—(Carbon, hydrogen and ash.) Jena-glass combustion-tubes, about 110 em. long and 12-15 mm. internal diameter, are best used. They are filled as follows -—

10 cm. space at each end.

6 to 8 cm. copper-oxide roll. 16 to 20 cm, space for boat. 45 cm. copper-oxide.

8 cm. lead-chromate pumice. 10 cm. silver spiral.

The furnace should be about 36 inches long; that used in this laboratory is a Fletcher combustion-furnace No, 2. The boat is of platinum, 10 cm. long. The purifying train (one for air and one for oxygen with a three-way tap so that the gas can be changed at once) consists of an Emmerling's absorption-tube and a washbottle with 1 in 2 potash, one washbottle with concentrated sulphuric acid, followed by two U-tubes filled with pumice saturated with concentrated sulphuric acid.t Between the three-way tap and the combustion-tube a small sulphuric acid washbottle is placed (so that the rapidity of the gas-current, can be easily watched), followed by a small mercury-trap. For the collection of the water a U-tube filled with pumice saturated with sulphuric acid is used. Before each combustion this is filled with acid overnight, the acid being drained oft just before weighing. Geissler bulbs, with an 8 em. drying-tube filled with freshly-crushed potash, are used to absorb the carbonic acid, followed by a small sulphuric acid U-tube to absorb the last traces of moisture, and finally a protecting tube of sulphuric acid pumice. It is hardly necessary to state that bulbs and tubes are refilled before each combustion.

The following points may be of use, although it is unnecessary to describe the combustion in detail. The weight of dry coal is as near '5 gramme as possible, this having been found the most convenient amount to work with for accuracy. The finely powdered coal (50-hole sample) should be used, and spread in as thin a layer as possible in the boat. The boat and coal should be dried for one hour exactly in the toluene bath immediately before required. When the boat, after final weighing before

Lunge. "Chem. Techn. Untersuchungsmethoden," 4th ed., vol. i, p. 228.

+ The pumice should be ignited with sulphuric acid before use to expel chlorides, ete, ;

10 The Coals Of South Wales.

combustion, is placed in the combustion-tube, it should rest on a strip of platinum-foil; this prevents any chance of its sticking to the tube, and diminishes the chance of any copper oxide adhering to it. Before commencing to heat the boat the oxygen is turned on in a gentle current. The copper oxide and silver spiral should be at a bright-red heat, and the copper oxide roll and lead chromate pumice at a dull red heat. When these are at the required temperature the boat is gradually heated and the combustion carried out in the usual way.

Duplicates should agree within :—

Hydrogen - - - '1 per cent. Carbon - - - me Se

It is important for the ete: oxide to be hot enough before the coal is heated, as possibly methane is amongst the first of the volatile products to come off, and it is well known that this gas requires a high temperature for combustion. In two of the earlier combustions made in this laboratory there seemed some reason to suspect that some methane had escaped combustion, as the difference between the carbon and hydrogen of the lower to the higher results gave the ratios of

Cen : 35 Be Oana i : 38 whilst in each case the ash agreed. On repeating these combustions concordant results with the higher values were obtained in each case. Another possible source of error, when duplicates agree in the hydrogen but not in the carbon and ash, may be due to neon ae combustion of the carbon. This was found to have occurred on more than one occasion, in each case the coal containing over 5 per cent. of ash, and having a high caking-power. It was, indeed, owing to this that a boat 10 em. long has since been used instead of one of the usual size, as the half gram of coal can be spread out into a thin layer, thus reducing the chance of incomplete combustion. The followin example illustrates this point. A boat 5 cm. long was used, aoe the caking-power of the coal was about 45.

=o. Fr G. 79°72 79°97 80°13 H. - 4°75 4°76 4°82 Ash - : 8°38 8°12 798

The hydrogens allagree within the lirnit of +1 per cent., but the carbons vary. Nos, 2 and 3 are within the -2 limit, but No. 1 is low. On looking at the ashes, however, it will be seen that the sum of ashand carbon is in each case the same.

It has been suggested that one cause of low carbon-results

ANALYTICAL METHODS. inl

might be due to some carbon monoxide escaping complete combustion to dioxide. At Mr. Seyler's suggestion a small washbottle, containing dilute sodium. palladium chloride solution, was placed behind the protecting U-tube, so that all gases from the combustion-tube, not previously absorbed by the U-tube and potash-bulbs, must pass through the solution, and thus render it possible to detect monoxide. On no occasion has there been any indication whatever of its presence, in spite of one or two low carbons which could not be accounted for, except by assuming a oe between U-tube and potash-bulbs, though none could be detected.

Caking Power.—This determination is not capable of any great accuracy, but is sometimes of use for comparative purposes. The coal is powdered to pass the 50-hole sieve, and is mixed with varying proportions of dry sand, which passes the 40-hole and stops on the 50-hole sieve: the weight of the two together is 25 grams for each experiment. The charge is plano in a platinum-crucible, and heated exactly as for an estimation of volatile matter. After cooling, the cake is carefully removed from the crucible, placed on a flat surface, and a 500-gram weight carefully placed on it. When the cake just crushes the cakingpower is reached. The caking-power is expressed as the weight of sand per unit weight of coal, thus :—

Sand. Coal. Caking Power. 20'0 50 4 22°5 2°5 9 24°0 1:0 24 etc.

It is important that the coal be as fresh from the pit as ae as in many cases the caking-power has been found to decrease by keeping.

Specific Gravity—Estimated in a specitic-gravity bottle, on about 5 grams of the special sample already described. Air is removed by boiling. Moisture- and ash-determinations are specially made on this sample, so as to give data for calculating approximately the density of the dry ash-free coal.

To correct for ash, either '01 may be deducted from the specific gravity for each per cent. of ash, or the specific gravit of the ash may be specially estimated and correction applied. In either case, the final result of correcting can only be regarded as approximate.

As an example of a possible error in the correction, where the specific gravity of the ash has been determined :—If the specific gravity of a coal containing 95 per cent. of pure coal and 5 per cent. pyrites (moisture and. other ash-constituents are omitted

B

12 The Coals Of South Wales.

for the sake of simplicity) be 1300, taking the specific gravity of pyrites as 5°0, the specific gravity of the pure coal would be 1251, But as 5 per cent. pyrites would become on ashing (assuming the reaction to be quantitative) 3°33 per cent. Fe,O,, and taking the specific gravity of Fe,O, as 5:1, the specific gravity of the pure coal as found would be 1268. As it happens, in this case the deduction of '01 for each per cent. of ash would be the nearer, but in the case where the ash as obtained by analysis is the same as that really contained in the coal, the direct method would probably give the more accurate figure.

ee

ANALYSES, 139-f

ANALYSES OF THE Coats or Sourm WALES, FROM ALL SouRCEs.

Abbreviations,

Geol. Surv.—Samples collected and analysed by the Geological Survey in the years 1901-7. '

GS. (C_ A. 8.)—Samples collected by the Geological Survey, but analysed by Mr. C. A. Seyler in the year 1905.

Adm. Rep.—" Report on the Coals suited to the Steam Navy," by Sir H. T. de la Beche and Dr. Lyon Playfair. 1st Rep., dated 1848 ; 2nd Rep., 1849; 3rd Rep., 1851. The First Report was printed in Mem. Geol. Survey, vol. ii, Part 2, pp. 539-630, 1848.

- Perey, 37, p. 325.—' Metallurgy," by John Percy, M.D., E-RS., F.G.S.,

d. 1875. The first number refers to the number of the analysis, the second to the page.

S.W. Inst. E.—Transactions and Proceedings of the South Wales Institute of Engineers.

C.G.—Colliery Guardian.

A.B.C. and C.—" Analyses of British Coals and Cokes collected and compared." Reprinted from the Colliery Guardian. (First issue in parts, not dated ; 2nd issue in 1907.)

Inst. M.E.—Transactions of the Federated Institution of Mining Engineers. Inst. C.E.—Proceedings of the Institution of Civil Engineers.

C.A.S.—Analyses made and communicated to the Geological Survey by Mr. C. A. Seyler.

Per C.A.B,—Analyses communicated to the Geological Survey, by Mr. Capel A. Branfill.

The carbon, hydrogen, oxygen and nitrogen are expressed in percentages calculated for the "pure coal," 7.e. for the coal after deduction for moisture, ash, and combustible sulphur. Thus in analysis 1, C. 88°66 + -H. 4°89 + O. 4:90 + N. 1°55 100.

wf

The — ratio is the relation of carbon to hydrogen. Thus in Analysis 1,

ee e113,

The percentage of volatile matter is calculated on the coal exclusive of moisture and ash. The fuel-ratio is the relay;on of fixed carbonaceous residue to volatile

; : : 100—30°80 matter. Th Analysis te —— 2°95, Thus in Analysis 1, ee The specific gravity is determined on the coal as received from the

colliery.

The ash is expressed in percentage of the dry coal, 7.e. coal dried at 1052 C,

The Coals Of

ape Re Local manent Plates 1-inch ocal Name o 1 Land Map. Ven. Colliery. 3-7, 7) 249 3 232 'Top Ngee Rock 4 249 ack - 2 5 248 Nine Foot- - - 6 231 Nine Foot- - - 3 232 Ras-las" - - 8 232 Rock or Horn - 9 248 Ni ine Foot i0 299 Big ' - ii 230 "Stanllyd - 12 229 lg - - 13 229 "Stanllyd ; 14 231 1g - - 5 247 Four Foot - 167 230 1s - 17 230 Stanllyd 18 248 Cribbwr - 19 231 Nine Foot- 20 249 Cwm Frood Rock Near Var teg Iron Co.'s Works 21 231 Gadley Nine Foot) One-third mile 22(1)} 231 Ras-las_ - Dowlais - - 23 248 Nine Foot - Llynfi - - 24 231 Nine Foot - Bute Pit, Hirwain 25 231 Nine Foot - Pwllfaron, Glyn Neath 26 231 Big - : - Gwaunclawdd -

Py 247 Nine Foot Morfa - -

28 249 Black Aberearn - - 29 230 Big 30 230 ° Big : 32 230 Big - 33 230 Stanllyd Big : 34. 230 'Big or Nine I Foot, Pontyberem — - 35 249 Black on panty ys Coal 36 232 Black Li lanhilleth -

37 231 Big - Ynyscedwyn— - 38 230 Middle Ve ein, Lower °Btanial 39 232 sie - - - Blaina . : 40 231 Big Abererat. -

(1) See notes at end of Table.

Og,

South Wales.

Authority.

Geological Survey — -

Adm. Rept. i, DP. 33, 62

'Adm. Rept. ii, pp. 35, 54

Percy, 37, p. 325 - -

Percy, 73, p. 332 - Percy, 83, p. 382 -

Percy, 95, p. 333 -

S.W. Inst. E., xxi,

p.

SW. Inst. E., xxi, p.

519, No. 422 S.W. Inst. E., xxi,

p. 519, Eby 224° CAS

"

" i. % a

bee P. 1 Lal, and

Ixxxiv, po

ap C. é (1907),

a BC. & ©. (1907), p. 129

Inst. M.E., xx (1900-1), p. 159

Cas. -

Percy, 8, p. 322

A.B.C. & C. (1st Ed.), p. 126

Analyses,

ze 7 (|Volatile) Fuel- Sp.

0 N. H Matter.| ratio qr.

ratio.

i 4°89] 4:90 1°55 1813 30°80 9°95 1:38 524] 4:99 1°60 16°84 34:41 (Qi) — aes 545 4°83 1°42 16°20 36°10 LT 11533 4°30] 92°74 1°32 21°31 16°65 5°00 1°365 3°49 98 116 27:04] 5:42 17:46 1-440 Sooo O7 28:36) S30 irsd 1494 343] 18 1:20 2761 5°30 LaSan 1°431 6291 3:36 1:20 14:09 33:20 201 1°255 4°65 3°03 1°45 19°54 — a 4°93 3°70 18°53 20°05 3°99 A411 2°27 22°78 10°02 8°98 3°86 2°35 24°30 625 15°00 — 3°43 3°20 97°22 5:40 17°52 5'34 8°35 16°16 30°40 2°29 5°41 8°40 15°93 31°40 2°18 3°55 2°53 26°49 5:00 19°00 3°63 2°67 25°81 517 18:34 3°83 2°31 24°51 576 16°36 3°74 2°30 25:12 550 17°18 3°75 2°04 25:12 5°75 16°39 3°47 1°20 QT 47 — --- 4:84] 3°48 99 18°73 em 1°34 477 7°28 110 18°21 :

: 3°57 3°22 26°11 850 10°76 3°81 2°37 24°62 5°83 16°15 xe

649} 4°81 Gee lel eon a ia 3°70 2°39 25°38 608 |*15°44 Sa

He tO O9 HERD RO ND OY OH LO DAIAD OWwode PTE WOTHHMOMWE

eee

Caos Sie

or w

2°0

The Coals Of South Wales.

No. on Plates| 1-inch Local Name of aire : land| map. Tein. Colliery. Authority. 41 231 Big - Ystradgynlais A.B.C. & C. (ist Ed.), p. 123 — 42 248 Yard - - Aberaman - |C.G., Lxxi., p. 641 43 247 Averageof Four Llanmorlais — - - p- 1,015_ - and Six Foot k 44 230 Stanllyd Park and Blaina A B.C. & C. (Ed. 1907), p. 367 45 spe lM @ leh - - - - Geological Survey — - 46 232 Old or Lower Nant-y-glo and Percy, 122, p. 569 - Four Foot Blaina 47 231 Peacock - - - - C.A.S. - - - 48 230 Little [Brass] - - - ha : - - 49 230 Peacock - - . - Das - . - 50 230 Brass - Cwmllynfell - Adm. Rept., i, pp. 34 & 58 51 230 Peacock - - - - C.A.S. - - - 52 231 |Peacock - - Gwaunclawdd - A.B.C. & GC. (Ist Ed.), p. 123 53 230 Peacock - - a CAS e " : 54 248 No. 2 Rhondda : S.W. Inst. E., xxi, p 55 248 Rock Vawr ~-!|Bronbil - Adm. Rept., ii, pp. 21 & 51 56 248 No. 2 Rhondda CAS. - : : 57 249 Rock - Machen - Adm. Rept., iii, pp. 39 & 51 58 248 No. 2 Rhondda - 7 CAS. : c : 59 248 Rock Fawr -!Bronbil - Adm. Rept. iii, pp. 43 & 52 60 230 Upper or Pen-y- Cwm Clie - - Percy, 130, p. 569 - iraig 61 248 No. 2 Rhondda- Glyn Corwg - Perey, [the mean of} 118-120, p, 569 62 247 Penlan Gas-coal| Penlan — - A.B.C. & C. (1st Ed.), p. 82 63 232 Meadow -— - - - . Geological Survey — - 64 232 Mynydd Black-! Blaenserchan - A.B.C. & C. (Ed. 1907), 9, 129 65 232 Meadow - - : P Geitouuas Survey - 66 247 Cribbwr - - Morfa Z -|§.W. Inst. E., xxi, p. " ; 516 67 231 Four Foot or Abercraf - -|A.BC. & OC. (Ist Ed.) Cornish p. 126 : 68 231 Cornish — - - Pwllfaron - Percy, 121, p. 569 - 69 247 Four Foot Morfa - -/S.W. Inst. E,, xxi, p. : 519 70 230 Wernffraith -! Primrose. - OG, tezi, p.2,015_-

Analyses.

BS 0, on lates — |Volatile] Fuel-| §S land C H O N. H Matter. ratio. Gr.

41 93°88 3°65] 1°85 62 2b2 -—— — 42 — — — ak —- 10°73 8°32 — 44 94°32 3°68 2°00 25°63 5°15 18°42 — 45 87°93 5°30] 5°50 EO 16°59 31°48 2°18 1°320 eS eee 46 90°74. O23 4°03 17°35 29°72 3°40 — 47 94°02 3°96 2°30 93°74 7°20 12°88 48 94°19 3°58 DPB: 26°31 5°12 18°53 49 93°67 ent feo) 2°60 2ouLt 5°84 16°12 —— Si ce a: 51 93°39 3°66 2°95 2ba2, H25 18°04 — bz 93°70 3°90 2°40 24°03 6°34 14°76 — 53 94°02 3°66 2°32 25°69 5°76 16°36 — 54 89°74 5°67 4°59 15°83 27°60 2°62 — 55 85°23 4°80| 9°35 62 17°76 40°56 1°47 1°292 2 ee 56 91°78 bl3 3°19 17°89 18°31 4°47 — Le ee 57 75°00] 5°15] 18°85 1:00 14°56 36°19 176 1°297 58 92°64 4°74 EG 19°54 17°33 Ant — ee 59 84°78 5°57| 8°94 "7a 15°22 43°26 13 1°301 ei RTs 60 93°58 4°05 Droit Zan 7°62 ne — 61 91°66 4°85 3°49 18°91 19°55 AN — SN ae 62 — eee — — 33°50 2°13 1°257 63 87°97 DO oe 2o Us 16°72 34°34 1°91 1°330 64 87°52 5°16| 6°26 1°06 16°96 —- — — 65 87°16 5°42)| 5°83 1°59 16°08 33°84 1°95 1°326 Se pees Ee 66 87°50 bulb aso 16°99 28°90 2°46 — 67 93°69 3°74 obi 25°05 6°73 13°85 — 68 93°83 3°95 222, 23°75 6°78 STi — 69 85°20 5°40 9°40 15°78 30°60 Dai} — 70 92°45 4°80 2°75 19°26 — — —

Ash,

1s THE COALS OF SOUTH WALES. No. on h lets ' Plates 1-ine socal Name o Aol Anthorit land map. Vein. / cet ' : 71 247 Four Foot Near Morriston — Rept. i, pp. 32 & 60 72 249 Mynyddislwyn - - - Geological Survey — - 73 249 3edwas Vein Bedwas - : Rept. i, pp. 40 & 63 74 247 Five Foot - |Mynydd-Newydd} S.W. Inst. 4; Xz 75 247 Penyfilia or Five Mynydd-Newydd) Adm. Rept., i, pp. 29 & Foot 61 76 247 Clyndie [Clyn-| Llangyfelach Adm. Rept., i, pp. 24 du] or Five 61 Foot hd is 231 Six Foot - - Glyncastle - Inst. M.E., xii, p. 238 ; also A.B.C. & C. (Ed. 1907), p. 386 78 248 Two-foot-nine - Blaen Rhondda Percy, 98, p. 333 79 248 Two foot-nine - Dunraven- - Perey, 101, p. 333 - 80(2)| 231 |Gadley Four! 1-3rd mile w. of Adm. Rept., ii, p. 35 Foot Aberdare & 53 - 81 248 UpperFourFoot Ffaldau - -|S.W. Inst. E., xxi, p. 508 ; C.G., Ixx, p. 639 82 248 UpperFourFoot Ynysyfaio - CG, Ixxv, p. 570, and Ixxxiv, p. 1,081 83 248 UpperFourFoot Dunraven- - Perey, 102, p. 333 - 84 248 UpperFourFoot Blaen Rhondda Perey, 99, Pp. 333 - - 85(3)| 231 UpperFourFoot Dowlais - - Perey, 36, p. 325 - . 86 248 — Foot of Aberdare Valley Adm. Rept., i, pp. 25 & yitryn 61 87 232 Four Foot - Ebbw ValeTron- Adm. Rept., i, pp. 42 works & 64 88 231 Four Foot - Hill's Plymouth Adm. Rept., ii, pp. 42 Merthyr & 65 '89 248 UpperFourFoot Aberaman Adm. Rept. iii, pp. 26 & 49 90 232 Ell - . Blaina- - Percy, 6, p. 322 - 91 230 Graigola - Primrose - +) O. Golem aos 3 92 232 Three Quarter Blaina — - - Perey, 7; p. 322 - 93 232 Three Quarter N antyglo and Perey, 123, p. 569 ¥ my (COP Vein) Blaina 94 249 Three Quarter - - - Geol. Sury, - - - 95 232 /'Three Quarter Ny. Varteg Iron Adm, Rept., i, pp. 30 & iy tock Co's Works 62 96 232 Three Quarter - - - Geol. Sury, - - : 97 232 Three Quarter - - - Geol. Sury, p Ss 98 230 Six Feet - Craigola Mer- C. G. Ixxi, p. 1015 thyr woe 1 al . e ; oY Six Foot - Primrose S.W. Inst. E., xxi, p. 508

Six Feet (partof) M ynydd-newydd

(2) and (3) See note at end of Table. ae

S.W. Inst. E

SREY hb.

ANALYSES, 19 No; on C Plates} — |Volatile| Fuel- Sp. land C. H. O N. H Matter.| ratio, Gr. Ash, 3-7, ratio. Al 91°81 4°66| 3°34 "19 19°70 18°10 4'53 Pel 34 72 86°94) 5°64] 5°84 1°58 15°41 37°52 1°66 S36 R73 Tis} 90°01 6°71 1°67 1°61 13°41 30°41 2°29 132 69 74 91°66] 4°87 3°47 18°82 18°80 4°32 64 en 75 88°66] 6°03] 3°68 1°63 14°70 26°04 2°84 eel oe 76 91°18) 3°97 4°85 trace 29°97 15°97 5°26 1°358 6'1 TT 93°63} 4°01 On 45 93°35: — — — 1193; SS 78 94°11 4°19 1°70 22°46 11°03 8°06 — 2°8 79 93°35 4°15 2°50 22°49 11°16 7°96 — 1°4 re 81 91°31 4°95 374 ifeheefosy| saltshargs) 4°33 1°29 9 ae 82 — — — — 12°02 (ay — 1°0 83 91.86] 3°93 421 93°37 10°61 8°42 — 3°8 84 92°74| 3°96 3°30 93°42 10°26 8°75 — 4'8 85 90°92) 4:51] 3°31 126 20°16 iy 86 92°93} 4°91 63 1°53 18°93 16°23 516 326) 32 87 92°10} 5°28 40 2°22 17°44 29°84 3°38 1275 1:5 88 91°44) 4°13) 3°95 48 29°14 18°19 4°50 1°359 2°4 89 93°40} 4°39 97 1°24 DOTA 15°22 way WeBOS Males 90 84°42] 5:48] 8°41 169 15°41 — — — 15 ee eg maa 91 92°73| 4°64 2°63 19°98 47 ee eras : 92 86°25 5:90} 6°13 ewe 14°62 -- oo Dio) eee tee 93 89°81 faye LIM 5°08 17°58 25°03 2°99 — ANS) 94 87°81] 5°09] 5°64 1°46 17°25 32°39 2°09 1314 62 95 87°19} 5°72) 5°85 194 152 42°12 isd 134 110 96 86°63} 513] 6°85 1°39 16°89 33°92 1°95 1°307 4°6 97 87°20} 510) 6°36 1°34 L710: 32°78 9°05 MSO erie ie) 98 ah et ee ei 12636 1 G:98s Ves [1-7 SS 99 91°70] 4°80 3°50 19°10 15°70 5°37 46 100 90°75) 4°73 4°52 19°19 20°30 3°93 — 60

20 THE COALS OF SOUTH WALES, No. on| gic ; Plates 1-inch ocal Name o ' ; {nd map Voie Colliery. Authority. 101 247 BineaorLoughor| Binea Farm — - lene Rept. i, pp. 28 & Fiery 102 247 Brynddwey Neath Abbey - Adm. Rept., li, pp. 13 103 230 Graigola - Ynysymond — - Rept., i, pp. 31 & 104(4)} 247 Ward's Fiery 14 miles E. of Adin Rept., i, pp. 27 & Llanelly 58 105 246 Fiery : Old Castle - Adm. Rept., i, pp. 26 & 106 247 |Graigola - — Birchgrove err Rept., ii, pp. 21 107 247 Brynddwey -/Neath~ - - Inst. C.E., viii, p. 101 108 230 |Graigola - - Waun-y-coed Percy, 89, p. 333 - - 109 232 Red - F e . E Geol. Surv. - 4 . 110 232 Big - - ) - Geol. Surv. - 111 249 Big - - Tirpentwys - A. B.C.&C. (Ed. 1907), § p. 132 112 230 Tregloin - - - - CAS. 4 - 113(5)| 230 |Tregloin - - CALS. a 114 247 |Cadoxton- - Cadoxton - Adm. Rept., iii, pp. 16 115 247 |Hughes - 2 - - CASS Ge - E 116 247 |Slatog - Weigfawr - S.W. Inst. E., xxi, p. 117 247 Rotten or Bodor Weigfawr - S.W. Inst. E., xxi, p. 118 247 Curly - - Weigfawr -|S.W. Inst. E., xxi, p. 119 247 Hedley's - - Cwrt-y-bettws - S.W. Inst. E., XXi, 'p. 120 247 Hughes - - Cwrt-y-Bettws - C.G., Lxxi, p. 1015 121 247 Hughes - - Weigfawr -|S.W. Inst. E., xxi, p. 122 247 |'Three Foot — - Mynydd-newydd! S.W. Inst. E., xxi, p. 123(6)| 249 Charcoal - - Abercarn - Adm. 2 Nalies lil, pp. 33 & 5 124 230 Lower or Welsh Cwm Clic - P me, 131, p. 569 125 248 No. 3 Rhondda! Penrhiw - — A.B.C. & C. (Ed. 1907), : 392 126 248 Graig - Dunraven - Phiey 4 100, p. 333 - 127 248 Graig - - Blaen Rhondda Perey, 97, p. 333 - 48(7)} 220 Red - Pwllbach - S.W. Inst. E., xxi, p.506 129 231 Xed : Dillwyn - es

(4) to (7)—see notes at end of Table.

A.B.C. & C. (Ed. 1907), p. 390)

ANALYSES, Did! Plates / — Volatile! Fuel- Sp. land C. H. 0. N. H Matter. ratio, Gr, 'Ash,

104° 94°68] 4:93; 1:09 22:38 — j.1:344 7-9 108 93°08] 4:47 2°45 20°82 1/1396 -4. GG js! To 111 90°58] 5:39] 3°39 64 16°81 as PRION BO a eo 112 9416] 3°66 2°18 2578 Vb 20 as23 1 90

SS 116 83°63] 5°28 11°09 P54. SHAG 2) 4eS0 ahi) Ad 117 85°69] 5°81 8°50 14°75 33°60 1°97 a es 118 85°93] 5:92 8°15 PAPE. 8770: 66 We ah BS 120 91°52] 4°71 pap) 19°43 ot aa Wd ae Se

124 93°71] 3.69 2°60 25M CAA 194A le oe Re ; 1 ee 129 93°56] 3:48] 2°91 '75 1 26°89 — —) 3o yee

22 TITK COALS OF SOUTH WALES. No. on lar: - Plates 1-inch Local Name of eave : Vand an, Vaan Colliery. Authority. 130 230 Red . - - : C.A.S. - . - 131 230 Red . - Cwm Gors A.B.C. & C. (Ed. 1907), p. 403 132 230 Red : : - C.A.S. é Z 133 230 Red - Cawdor - - SW, Inst. E., xxi, p.506 134 230 Red - Ynysygeinon §.W. Inst. E., xxi, p. 506 135 230 Red Boe ts - |CAS.-— setae 136 230 Pontyberem No. Pontyberem - A.B.C. & C, (Ist Ed.), 1 [Gras-uchaf ] p. 58 137 230 Clynhebog Pontyberem - A.B.C. & C. (Ist Ed.), [Lower Pump- p. 58 quart] 138 230 Middle' - - - C.AS. 139 230 Lower - . C.AS. - 4 140 230 Lower Tri- - : CASS. : - - 141 230 ew Cross New Cross A.B.C. & C. (1st E Hands [Lower| Hands p. 83 ( 4), Pumpquart] 142 230 |Lower Pump- CAS: E : quart 143 230 Lower Pump- CAS: % 2 e quart 144 229 Big - - - - C.A.S. - - 145 229 Drap : : - C.A.S. ae 146 229 |Green~ - sj 'C.AS - 147 248 Cae David - Ty-chwyth Percy, 73 399 : 148 248 Six Foot - : Dunraven : faa as i 149 248 /Six Foot - -|Llynfi - -! Percy. 74 Pp. 332 ; 150 248 Duffryn - Livni e Perey, 75, Dp: 332 : 151 248 Yard - -|Llynfis- - Perey, 77, p. 332 152 247 Five Foot (top)- 7 Geol. Surv 153 247 a (middle) : x Raping took i Z 154 247 (bottom) : 4 tS " : r 155 247 (top) - : : 2 ' 156 247 (middle) ae . '1 157 247 (bottom) 2 ei ' 158 Q47 (top) - i: r 159 247 (niddle) "a ? ' ; " 161 230 Peacock Brynhenllys Per 162 230 Big - Ynyscedwyn a et . : ; 164 231 Red - Dillwyn - "3 : k : 165 230 Big - - 'Gwauncaegurw 166 230 Peacock - — - Se ee ee 167 230 |Big - - -/Garnant - . i i 3

ANALYSES. 93 ates —— Volatile) Fuel- Sp. land| © ut 0. N. Matter.) ratio. Gr. ah, 3-7. ratio. 130 93°03| 3°51 3°46 26°50 Pig o4) ) 3°6

131 94:08] 3°79 2°13 24°85 Ge ied) 27 133 93°42) 4:02 2°56 23°24. 650h-/1438 — 28 134 92°58] 3°91 3°50 23°68 770° 4] 11°98 3°0 136 fos 5°39 17°54 — (ley 137 ee 554 17°04) — '9 138 94'31| 3°64 2°05 25°91 5°24 18:08 ee es hy; 139 94°09] 3°58 2°33 26'28 5112 18°53 a 17 140 94°1 3°6 23 26°14 5°10 18°61 — 2°6 141 93°87| 3°41 2°72 27°53 3°83 25°1 8 142 93°00| 3°68 3°32 25°27 5°20 18:28 ch 143 94°38] 3:14] 1°16 87 30°06 5:17 1819 '8 SS ee ——. 145 92°59} 4°54] 1°30 be 20°39 — — 14 146 93°98] 3°88 2°14 24°22 671 13°90 — 24 147 87°99] 5°64 6'37 15°60 34°35 191 — 42 148 92°73] 3°95 3°32 23°48 12°03 73 — |3°0 150 89°75| 4°92 5°33 18°24 23°33 3°29 39 154 91°49] 4°45] 2°49 1°57 20°58 ie 4°63 UBB Beil 158 92°40) 4°38] 2°04 118 21°10 16°47 5°07 1°369 5°9

161 92°13] 3°76 4°11 94°54 — eg 162 92°46] 3°20 4:34 28°87 -- — 16 163 93°92| 3°57 Qi 26°26 — '0 ae ae: 164 93°42] 3°39] 1°65 1:54 27°54 9:00 101i Soar nl —— 165 94:49] 3°67 1°84 25°77 oa ayy 166 93°80} 3:16 3°04 29°64 ma oa — 9 167 93:17] 2°12 4°71 43°85 oe bs '4

See footnote on p. 53.

No. ol

The Coals Of South Wales.

Plates 1-inch Local Name of

land - map.

Vein. Colliery. Authority. Peacock - International - 5 - . Big - F 7 " " . Stanllyd - - Caerbryn - : Big - -|Onllwyn - " : 3 Big - - Abereraf - ali Eighteen Foot Pwllfaron - - Perey, a 333 -

ack " Glyn - A.B.C, & C. (Ed. 1907), p. 124 Big - : Blaencaegurwen Per C.A.B. - - - Four Foot Ystradgynlais - 3 - - - Lower Level and Bonville's Court Per C.A.B. and A.B.C. Kilgetty and Kilgetty & C.(Ed. 1907), p. 404 ig - -|Carway - - A.B.C. & C. (Ed. 1907), p. 369 Ha Se eae . - Geol. Surv. Mynyddislwyn " " 4h fliers - Red Ash - . - - - - Five Foot (top) - : C.A. - 2 - (middle) ee r £ (bottom) - - " 3 Four Foot (top) - sorte, 2 (bottom) - a - - - Black - - Celynen A.B.C.& C, (Ed. 1907), Three-Quarter Tirpentwys A RG & C. (Ed. 1907), Green Vein Cae Pontbren alice. & C. (Ed. 1907), Peacock - -|Qarnant - -/ABC&@. (2d. 1907), pp. 369 & 370 Stanllyd and/ Emlyn - A.B.C. & C. (Ed. 1907) Pumpquart 371 : Yankee - -|Clyne Valley A.B.G.& C (Ed. 1907), ). 382 Three Foot Clyne Valley - rwitel & C. "Ed. 1907), ). 384 Z [Box Big] - Glan Mwrwg - Aho. & C. (Ed. 1907), , oy Forest — - Penrhiw - - a oo C. (Ed. 1907), Lynch Lynch 4 A. B. c . C. (Ed. 1907), Timber - Hill Pit, Hook -

'i

Nie. -&C. (Ba. 1907),

/ ANALYSES, D5 ates 'Volatile! Fuel- Sp. land ¢. H. 0 N. Matter. ratio, Gh. Ash: 168 O3 70 oe 3°05 29°12 1:8 169 95°15) 211 2°74 ADOT — 2:3 170 93°20) 3712) 9°74 94 29°90 — 7 171 ped — 5°48 17°26 1'2 ee ape 93°16} 3°52 Shor 26°43 1°4 ilegs, Co} $9 8 aa 4°70 42'97° — als 7 176 91°81] 3°99 4°20 23°00 — 17 eee Soon ee 177 95°68] 3°04] '51 77 31:50 a ibyp (a 178 93°72} 3°68 2°60 95°54 5'89 15°97 eG 179 89°73} 5°71] 2°88 1°68 ilisyvAl 28°69 2°49 P3t |LOS 180 87°66} 6°09} 4°38 1°87 14°39 30°14 2°02 1°334 5°2 181 87°87] 601) 4°67 1°45 14°62 36°25 1°84 1346 |533 182 88'°33| 5°79] 4°27 161 15°26 32°79 2°05 E313 1 35 — 183 92°55} 4°88 257 18°95 14°82 5°75 zene 79 184 91°26| 4°56 4°18 20°0 16°26 Sl) a 79, 185 92°70| 4°44 2°86 20°9 12°96 6°72 — 57 186 91'°54| 4°62 3°84 19°8 14°96 5°69 — 29, 187 92°52] 4°78 2°70 19°4 Lora 5°51 — |12°3 a 188 89°27) 5°60] 3°44 1°69 15°93 25°84 2°87 —— 4°3 189 89°64| 4°37] 4°99 1°00 20°51 —s a 5:0 190 94°37} 3°69 1°94 QorbG — a 1'4 191 93°94| 3°77 2°29 24°93 6°10 15°38 —— 1°8 ASS eee Oe eee 192 93°31| 3°02] 2°52 Lets 1590-011 wee ete a Fi ee ee 193 88°12} 5°57 6°31 15°82 30°81 O94. — 2'3 195 ae, as — a 143 5'48 ae 4°4 196 86°38} 5:37| 6°97 1°28 16°07 — 1'8 197 he ues — — — 26'93 271 — 2°4 198~ 94°72] 3°25 2°03 29°12 4°74. 2071 — '8

See footnote on p. 53.

26 The Coals Of South Wales.

No. on hase a ; Plates 1-inch ocal Name o . at land} map. Vein. Colliery. ah

199 228 Bonville's Court -" . C.A.S. 200 228 . Reynaiton - A.B.C. & C. (Ed. 1907), p- 404

201 230 Little Vein - LittleVeinSlant, A.B.C. & C. (Ed. 1907), Ammanford p. 367

202 248 Cae David - Llynfi . - Percy, 76, p. 332. ;

203 247 Four Foot - Clyne Valley A.B.C. & C. (Ed. 1907), p. 383

re essnnsansnsemmmnatinuees onsen oon sa ene

(1) No. 22.—The figures for Pure Coal, as given in Percy, are incorrect. The figures here given have been obtained by recalculating from " Composition per cent., exclusive of water only."

(2) No. 80.—The analysis here quoted is recalculated from the figures of "Gadly Four-Feet Seam," as given on p. 57 of the second Adm, Rep. oe en: 1, Analysis 2 adds up to 100°97, thus giving no oxygen in the coal,

(3) No. 85.—See Note to No. 22.

(4) No. 104.—The N, as given on p. 12 of Adm. Rep. 1, should read 1°02 (as on p. 59). The analysis adds up to 100°69, but a note on p. 58 states "The pure coal contained only 3°82 per cent. ash." There is obviously something wrong with the oxygen and ash, but this would

nee ANALYSES, on

a 0, on C

ates| 4 — Volatile] Fuel- Sp.

land C. i. O. N. |Matter.) ratio. Gr. Ash, 3-7, ratio. 199 93°26| 3°28 3°46 28°43 — 200 — oe — os 5°89 15°99 ita 201 94°36| 3°63 2°01 26°02 — M5 202, 90°78 5°13 4°09 17°69 24°74. 3°04 — 5°4. 203 88°80) 5°36 5°84 16°55 30°30 231 — 2°6

not affect the C/H ratio, though rendering the analysis as calculated to " Pure Coal" doubtful.

(5) No. 113.—The figures given represent the mean of two different specimens. The greatest difference on the Pure Coal was '01 in the C and '08 in the H. The percentage of ash in both specimens is, however, given.

(6) No. 123.—The analyses as given on pp, 5 and 55 differ in O (9°76 and 9°96). In both cases the analyses add up to over 100 (102°00 and 102°20). As the O is obtained by difference, the figure should read 7°76. This value, therefore, has been taken.

(7) No. 128.—A similar case to No. 118—see note (5).

CHAPTER IV: ACCURACY OF CoAL ANALYSES. By W. Potiarp.

ALTHOUGH practically every author on the subject of coals and coal-analysis has discussed, or, at any rate, alluded to the question of errors in coal-analysis, it will probably be of assistance if a few examples of possible errors are given before examining the table of analyses. These examples may be thought to be exaggerated, but probably all, and possibly some others not mentioned, will be met with sooner or later whenever a large amount of coal-analysis is done.

1.—Proximate Analysis.

In the proximate analysis of a coal it is important to work as much as possible under constant conditions, and so long as this is done duplicate estimations agree fairly well. If, however, the strength of flame, time of heating, size of crucible, &c., be altered, the results will almost invariably differ, and, unless these details are looked after, will be unreliable. Muck* points out that the addition of powdered quartz to a coal increases the coke, and consequently lowers the volatile matter, so that if two coals are being dealt with whose composition is identical as regards combustible constituents, but which differ in the amount of ash, the proximate analysis will be to some extent misleading.

From some experiments carried out in this laboratory it was found that an increase of water. gave an increase in the volatile matter. The following figures illustrate this point. In the tirst column is the analysis of the original coal,in the second the coal plus an addition of 5 per cent. water, in the third with an addition of 12 per cent. water. The results are calculated to the pure coal (i.e., less moisture and ash).

Volatile IGDUON: deverseaubvec ee 37°02 oF 37°86 ae 38°44 Fixed carbonaceous residue 62°98 ee 62°14 ua 61°56

The presence in the coal of carbonates also affects the results. In a coal which contained 12 per cent. carbonic acid (present in the coal as carbonate of lime and magnesia), recently analysed in this laboratory, the amount of carbonic acid left in the coke after the estimation of volatile matter was only '9 per cent., hence 111 per cent, had gone off as volatile matter. Further, it is not possible to say to what extent the reaction CO, + C 200 goes on but this must have a considerable effect on the result. ;

Pyrites in the coal must also have some effect, but it is not

"Chemie d, Steinkohlen," Bonn, 1876, p. 16,

Accuracy Of Analyses, 29

easy to Judge to what extent. It will be readily seen from the above remarks that the proximate analysis is not sufficiently reliable as a basis for purposes of classification,

2.—Ultimate Analysis.

The way in which moisture is estimated may affect the percentage of practically all the constituents when expressed in ieee of the pure coal. In the following example the

difference between moisture obtained by drying in the toluene bath and over sulphuric acid in vacuo for 24 hours was '3 per cent., which would give (according to which is the true figure) the following alternatives :—

: Value of moisture Value of moisture det ate : by sulphuric acid in toluene-bath. Hae EN Carbon - - - - 81°00 81°00 Hydrogen - - - - - 4°59 4°56 Oxygen - - - . - 5°48 5°19 Nitrogen - - - - - ieee. 1:23 ' Combustible sulphur - - - 2°18 2°18 Ash - - - - 3°35 Jal Moisture - - - - Dalia 2°47 Or calculated to pure coal :— Carbon - - - - 87°76 88°07 Hydrogen - - - . - 4°97 4°96 Oxygen - - - - 5°94 5°64 Nitrogen - - - - - 1:33 SB

It is exceptional to find as big a difference as '3 per cent. in moisture by the two methods, but where coals rich in moisture are being dealt with it is better to estimate by both methods, as an idea of the possible error in composition is obtained. As already stated, in all coals analysed in this laboratory the figures obtained in the toluene bath have been taken, as that is believed to be the method more generally employed.

Ash.—By ash is meant all non-combustible matter in the coal. The value obtained depends to some extent on how the ash is estimated. For instance, the value for the ash left in "the combustion-tube is almost invariably higher than that obtained by ashing in the muffle. The reason appears to be that in the combustion-tube, where the coal is burned in oxygen, more of the sulphur is converted to sulphuric anhydride, which combines with any lime in the ash, whilst in the mufile the atmosphere is less highly oxidising, so that more of the sulphur goes off as a lower oxide, instead of combining with the lime in the ash. The following case supports this view :—

A coal gave 480 per cent ash in the muftle and 5:26 in the

30 The Coals Of South Wales.

combustion-tube. The sulphur in the lower ash was '11 per cent. in the higher 30 per cent. If the difference of the two sulphurs (19 per cent.) be calculated as SO,, 47 is obtained, whilst the difference in the two ashes is '46 per cent.

In every case where the ash has been estimated in both ways the muftle has given the lower result both in ash and sulphurin-ash. Should minerals containing ferrous compounds be contained in the coal, these will, on combusting the coal in oxygen, become (to a great extent, at any rate) ferric. Hence the ash as found by analysis will be greater than the original ash in the coal, and the oxygen which is obtained by difference will, consequently, be too low. To take a possible case: the composition of a coal as found by analysis is :—

LV Sy ee ot te Moisture - - - -

' MV ee ay SS ae ee ee

oe

Supposing that the ash as here found contains 2 per cent. of Fe,O; which was present in the original coal as FeO, the real ash would be represented by 86—20 + FeO, equivalent to 2:0 Fe,O,, which is 18. Hence true ash is 8-4 instead or 8°6, and the oxygen 1:4 instead of 12. Recalculating both to the pure coal (ie. coal free of water, ash and combustible sulphur), the following figures are obtained :—

Uncorrected. Corrected. Difference. C - - 92°69 92°48 "21 H 4°43 4°43 O . - - 1°33 154 20 N - - - 155 1°55 — fejsak © - - 21°40 21°36 'O4

(The above 2 per cent. of Fe,O, represents 23 per cent. of the ash. Cases are given by Percy where 44 per cent. of the ash of a Welsh coal was composed of Fe,O,, but it is not possible to say if any of it was present as FeO in the original coal. This error is hardly ever likely to be of serious importance except in coals abnormally rich in ash.)

Pyrites—We ref takenextthe effect of pyrites. When coal containing this mineral is burned in ox gen, the pyrites is converted into ferric oxide and oxides of ae Gs ; the latter are absorbed by the lead chromate in the combustion-tube, while the former remains in the boat and is weighed with the rest of the ash,

Accuracy Of Analyses. 31

The pyrites cannot be regarded as part of the organic combustible constituents of the coal any more than the rest of the ash and the moisture, but for every 240 parts of weight of pyrites present in the coal 160 parts of ferric oxide and 128 of sulphur are being counted. 'The effect of this is that the oxygen, which is obtained by difference, is too low. The following example illustrates this error :—

(All the combustible sulphur has been assumed to be present as pyrites.)

All § taken as FeSs, and the equivalent Fes O; deducted from

Composition as obtained by

analysis. 'owe

C - 83°65 83°65

H - - - 4°02 4°02

O - - - Heyy 2°01

N - - - 1°45 45

S. combustible - 2°93 FeS AT Vee

ee MLE ear!" Ach leas For; Lemar ee equiv.to 4°17 FeS: 3°53 8 :

Moisture : veny, 117

Recalculated on to ' Pure Coal.' Difference.

C - - 2 92°65 91°80 *85

H Bee SAT, 2 4°45 4°41 04

O - 1°30 2°20 '90

N - - - 1°60 1°59 Ol

C/H ratio -— - 20°8 20'8 —

Carbonates.*—Carbonates in a coal are more or less decomosed during analysis and give off carbonic acid gas. This is absorbed by the potash-bulbs and is weighed with the carbonic acid formed by the combustion of the carbon of the coal, the result being that the carbon is too high, the true ash too low, and the oxygen too high, When the results of the analysis are calculated on the pure coal all constituents will be affected. In the following example the 6-2 per cent. of ash is assumed to contain 2 per cent. of calcium oxide which was originally present as calcium carbonate. Hence ash less CaO is 42 per cent., and CO, equivalent to the CaO, 157. This makes the ash, plus nonorganic constituents, 7°77 instead of 6:2 As in combusting the coal all the CO, is assumed to be driven off, the percentage of carbon will be too high by C/CO,, or 3/11 of 1°57, or '43 per cent.,

Of, Alix and Bay. C.R., vol. exxxix (1904), p. 215.

82 The Coals Of South Wales.

and the ash too low by 157 ea cent., the difference falling on the oxygen. The effect would thus be :—

Uncorrected. Corrected. Difference. C - - 85°23 84°80 — H : - 3°64 3°64 -- O - - 1°83 69 — N - - 1°29 1°29 S combustible 1°81 1°81 sh - - 6°20 rer as or calculated on to pure coal :—

C - - 92°65 93°79 1°14 H - - 3°96 4°03 'O7 O . 1°98 '76 1°22 N . - 1°41 1°42 '01 C/H ratio - 23°4 23°3 l

(No notice has been taken of the sulphur in this example, which is only to illustrate the error causec by carbonates).

In practice it has been found that the amount of CO, left in the ash varies considerably with each estimation, so that to make the necessary correction the CO, has to be estimated gs ecially in the ash left after each combustion. When this is done duplicates agree well,

he next analysis is quoted as showing how the type of coal may be mistaken unless correction is made. It is an extreme case, but one that has actually occurred in the course of coalanalysis in this laboratory. The coal in question was one that had been baked by a whin-sill. It contained 25-2 per cent. of ash and 122 per cent. of CO,, so the true ash (the inorganic or incombustible portion) was 37-4 per cent. The figures give the composition of the pure coal (ie. free from ash, moisture and aa eee sulphur), the first column uncorrected, the second the true composition :—

Uncorrected, Corrected. Difference, C - - 88°69 93°13 4°44 H - 2°80 301 21 O - 18 2°44 4°74 N - - 1°33 1°42 '09 C/H ratio - 31°7 30°9 "8

not possible,

Where both carbonates and naturally be complie

with the lime or ma combustible sulphu

pyrites are

ations, as the oxides of su gnesia of the carbonates, r and increasing the sul however, to correct for this,

resent there will phur will combine thus lowering the phur-in-ash. It is

Accuracy Of Analyses. 33

Hydrous Minerals—A possible source of error affecting the hydrogen would be the presence in the ash of minerals containing water of constitution not driven off at 105° C.* As an example (and probably an extreme one) were 5 per cent. of kaolin (which contains about 14 per cent. of water) to be contained in a coal, and were all the water (-7 per cent. on the sample of coal plus ash) driven off and isontied in the U-tube, the Pe asdhan would be too high by 1/9th of -7 per cent. or '08 per cent. This would give a difference of °3 to 5 on the C/H ratio, according to the class of coal. It is hardly likely, however, that a coal would be met with containing so great an amount of hydrous minerals, :

Deterioration on Keeping.—The fact that many coals deteriorate, and some are liable to spontaneous cornbustion when stored has been the subject of a large number of papers. Percy (. 289-300) goes into this question, quoting the researches of

einitz Fleck and Hartig,t E. Richterst and others, pointing out the fact that it is something besides the pyrites which produces the change. From more recent observations it may even be doubted whether pyrites, except when present in large amount, produces spontaneous combustion, From the discussion on a paper entitled 'On the Prevention of Bee au Combustion of Coal at Sea, § opinions appear divided, though it seems that whilst pyrites does not fire when pure, it is lable to heat and take fire 1f mixed with organic inatter, as in coal.

Prof. Fischer|| has published a paper going fully into the question and giving a résumé of the older investigations. He tried the effect of bromine on coals and found that both addition and substitution products were formed, the addition products showing the presence of unsaturated compounds. When moist air was passed over powdered coal carbonic acid and water were formed, the coal increasing in weight. If then heated to 120° or 150°C. a loss in weight occurred due to more or less of the carbonic acid and water being driven off. It was found that powdered coal absorbed oxygen more rapidly than lumps, as was to be expected. After a coal had been subjected to this slow oxidation in moist air, it was found to absorb far less bromine than the same sample before oxidation, an additional proof that change in composition had occurred. A test, based on the bromine reaction, is suggested for finding out whether a coal is liable to spontaneous combustion or not. If this test is really satisfactory it should be of considerable value to those who store or transport large quantities of coal.

*Cf. C. von John. Verh. d. KK. Geol. Reichsanstalt, 1904, p. 104.

+ "Die Steinkohlen Deutschlands u. a. Laender," 1865, vol. ii, p, 221.

+ Dingler, Polyt. J., vol. excv, 1870, p. 315 and 449, vol. exevi, p. 317. Also Wagner's Jahresber. 1870, vol. xvi, pp. 758-778.

§T. W. Bunning. Trans, N. of England Inst. M.E., vol. xxv, 1876 p. 107. : -

Z. Angew Ch., 1899, pp. 564, 764, 787.

34 The Coals Of South Wales.

The following are, briefly, the conclusions drawn from this paper. Coals contain varying quantities of unsaturated comdaly which rapidly absorb oxygen, thereby pecs weight

ut deteriorating in coking properties and calorific value. Another series of compounds also occurs which take u oxygen, but give off carbonic acid and water in the process. The latter process, which is usually slow, produces a loss in both the weight and value of the coal. A coal on storing therefore may gain, lose, or remain constant in weight, according to the quantities and relative proportions of the two classes of compounds present, but will almost invariably deteriorate in value. When coals are stored in a cool dry place the alteration is, in most cases, inconsiderable. Moisture certainly assists in the oxidation of the coal. The effect of pyrites on spontaneous combustion is undoubtedly overestimated. The value of ventilating stored coals is doubtful, as although ventilation will help in cooling, it will supply the oxygen necessary to produce combustion.

n connection with the absorption of bromine by coals, it should be mentioned that F. Hart has recently published the results of an investigation on the absorption of iodine, and on the action of sulphuric acid and alcoholic potash or coals. Alcoholic potash extracts a dark substance from caking coals which readily cokes, whilst the coal after this treatment loses its coking properties.*

In order to see to what extent the composition of coals would be affected by keeping, four of the samples stored in this museum were recently re-sampled and analysed afresh, with the following results.

In each case the first column gives the composition of the fresh coal, sampled and analysed soon after it was sent from the pit, the second after it had been stored in a tin-box, the length of time stored being in each case stated. The coals have been stored in the basement of the Jermyn Street Museum, where they were not subjected to great changes of temperature,

Nine-Foot Vein. Anthracite. Stored Four Years.

Analysis in 1903. Analysis in 1907,

Caw ee So 93°15 93°13 Ee \aLe 3°59 3°52

OP. - - . 1°89 1°99 a 1°37 . 1:36

Sp. Gr. (pure coal)+ - 1°396 1403

C/H ratio . . 25°9 26°5

ae r snamememmmenen ee ee

In this case the change may be taken as nil, all variation being within experimental error

® Chem. Zty., vol. xxx p. 1204 ; and vol, xxxi, p, 640. + See Footnote on next page," pin

Accuracy Of Analyses,

Nine-Foot Vein. Steam Coal. Stored Four Years.

Analysis in 1907.

Analysis in 1903. OSs - - - 91°58 hee - - 4°51 Oe - - 2°36 kt. ae 1°55 Sp. Gr. (pure coal)* - 1316 C/H ratio - 20°38

91°34 4°42 2°67 1°57

The variation here is almost within experimental error, but the change, slight as it is, is in the direction to be expected.

Mynyddislwyn Vein. A Bituminous Coal. Stored Four Yeurs.

Analysis in 1903. Oe - - - 86°94 ie sade 7% Y 5°64 @y - - - 5°84 N - - - - 158 Sp. Gr. (pure coal)* - 1:290 C/H ratio - - 15°4

Analysis in 1907.

bt Or Or

THOR ot Cunt w Or

15°8

Top Coal of Rock

Vein. A Bituminous Coal. Years Seven Months.

Stored Five

Zohq

Sp. Gr. (pure coal)* -

C/H ratio

Analysis in 1901,

5°45 4°83 - ' 1°42

- 16°2

Analysis in 1907,

87°11 5°94 1°55

16°1

Analysis in 1907,

87°34 5°34 5°78 1°54

16°3

First column, original analysis; second, original fine-ground sample, stored in a bottle all the time; third, original sample stored in a tin box and resampled after the years.

The ap obtained

case. (See under Specific Gravity, page 11.)

ecific gravity of the "pure coal" in the above cases has been y Pivetuae tty the specific gravity of the ash as found in each

36 The Coals Of South Wales,

The difference between the two stored samples may well be only due to experimental error, but with both the bituminous coals the difference between the fresh and the stored samples is marked.

It is noticeable that the anthracite has altered least (if at all), the steam-coal only slightly, whilst the bituminous coals have changed considerably. In each case the change is in the same direction, and though, as already stated, no great accuracy can be claimed for the specific gravity of the pure coal, owing to the possible sources of error discussed on pp. 11 and 29 (to say nothing of the pyrites having partially decomposed in the stored specimen), yet the general indication is that the greater the alteration in the composition the greater the alteration in the specific gravity. The differences are :—

Loss of carbon - - ('02) "24 1°39 96 Gain in specific gravity (007) 013 026 020

The change, at any rate in the bituminous coals, is greater than can be reasonably put down to experimental error.

The alteration is similar to that observed by Richters, Fleck Bischoff, and others, and quoted by Percy (p. 289-298), possibly with the exception of specific gravity, as the variation in specific gravity in the examples given by Fleck (Die Steinkonhlen Deutsehlands wu. andere Laender, vol. ii., p. 219) 1s only -011 in one case and less than '01 in the rest, although the variation in carbon is greater, and in the cases quoted by Richters,* where some coals showed an increase and some a decrease in specitic gravity. Unluckily the specific gravity of the ash is not given, so it 1s not possible to calculate the results for the pure coal. The great difficulty in commenting on results of this kind is that it 1s Impossible to say whether any constituent remains the same, with possibly the a of ash, and, as has already been shown, the estimation of ash is at the best of times unsatisfactory, Were the alteration of coals by storage to be at any time reinvestigated, it would be well to take a pound or two of the finely ground sample and thoroughly mix with it, say, 1 per cent. of some inert and easily and accurately estimated substance (e.g. gold-dust), then divide up into lots to be periodically examined. here would then be one constant from which to éalculate the changes that had occurred.

mv ed ee : The following is a summary of the approximate errors so far considered :—

Dinglers Polyt. J., vol. exevi (1870), p. 321.

Accuracy Of Analyses. 37

C H O N C/H. per cent. per cent. per cent. per cent.| ratio Ferrous minerals in ash - ) — 2) — 1 Pyrites - - - - 85 'Ob '90 'Ol nex Carbonates - 2 B 114 '07 1°22 'Ol "if Ditto in extreme case - 474 2 Ary sil °8 Hydrous minerals - - — "af -— — 1 4 Maxinum observed alter- 1°39 21 1°43 ity 'bl ation in four Welsh coals after storage

No great accuracy is claimed for these figures, they are only intended to show in what direction, and approximately to what extent, the composition of a coal may be attected.

The Coals Of South Wales.

Chapter V.

COMPARISON OF DIFFERENT BANDS OF THE SAME SEAM AND CoMPARISON OF DIFFERENT SAMPLES FROM THE SAME SEAM

IN THE SAME LOCALITY. By W. Pouuarp.

After considering the possible analytical errors the following questions arise:—What variation is met with in the composi-

tion of— 1, Coal in different parts of the same seam (ie., top, middle, and bottom coals). 2. Different samples from the same seam and pit.

Po Analysis No. C °F, H°/, j|jO&N °%/o fate 61. (Nos. 118, 119, 120 of Percy)

TopCoal - - - 91°63 4:98 3°39 18'4 Middle Coal - - 92°45 4°89 2°66 18°9 Bottom Coal - - - 91°30 4°72 3°98 19°3

152. Top Coal - - - 92°65 4°45 2°90 20°8 153. Middle Coal - - 90°58 4°33 5°09 20°9 154. Bottom Coal - - - 91°49 4°45 4°06 20°6 156. Middle Coal . - 88°64 4°72 6°64 18°8 157. Bottom Coal - - - 89°98 4°82 5°20 18°7 158. Top Coal —- - - 92°40 4°38 3°22 S11 159. Middle Coal - - - 91°36 4°32 4°32 21°2 160. Bottom Coal - - - - 90°48 4°34 5°18 20°9 183. Top Coal . - . 92°55 4°88 2°57 18°9 184. Middle Coal - - - 91°26 4°56 4°18 20°0 185. Bottom Coal- - - 92°70 4°44 2°86 20°9 186. Top Coal — - - - 91°54 4°62 3°84 19°8 187. Bottom Coal - - - 92°52 4°78 2°70 19°4

Under the second heading twenty cases occur, in some of which there are more than two analyses from the same locality available. These are given in the pollawi pages.

Different Samples From The Same Seam, 39

Vein, Q Q s C/H Fuel- Ons Ho [O&N®/o ratio. ratio, Black [or Ras-las] - - 88°66 4°89 6°45 181 2°25 " " 86°85 4°77 8°38 18°2 Difference - - 1°81 12 1°93 el — — a Eee a " " 3 & 90°74 4°84 4°42 18°7 — . " " a 90°45 5°28 4°97 i a e , : — Maximum difference 2°50* *44 2°25" 19 — Black [or Ras-las] - - 87:49 5°33 718 164 1°74 " " 89°27 5°60. 5°13 15°9 2°87 Difference - - 178 "OT 2°05 5 Tels Big [probably above the 93°77 3°74 2°49 25'1 14°46 Ras-las] % x - 93°63 3°70 2°67 25°3 ss "p - 93°99 3°76 2°25 25°0 — : sf - 93°87 3°76 2°37 25°0 13°87 Maximum difference "36 '06 "42 3 69 Big for Ras-las] —- - 93°56 3°57 2°87 26'2 15°95 a e 933i 3°57 3:22 261 10°76 i. . 9946 3°20 434 28'9 oe Maximum difference 110 '37 1°47 2°8 5°19 Four Foot[of Clyne Valley]| 88°80 5°36 5°84 16°6 88°51 5°02 6:47 17°6 2°56 Difference - - 29 "34 63 1:0 25 Big [or Ras-las] - 93°87 3°59 2°54 26°2 22'8 i 2 s 2 93°97 3°50 2°53 26°9 16°2 Fs e - - 94°49 3°67 1°84 25'8 a Maximum difference "62 pikes '70 i? 66

Greatest difference observed in this Table,

40 The Coals Of South Wales.

é Cc Fuel- Vein. C°/,5 H°/, 0 & N/a AS ratio. Big [or Ras-las] - 93°91 3°70 2°39 25'4 15"4 Difference - "75 18 93 10 "Se Little [or Brass] - - 94°19 3°58 2°23 26°3 18°5 Difference - - '17 05 22 2: — Peacock [or Brass] - - 93°39 3°66 2°95 25°5 18°0 os Difference - - "41 50 "09 21% Rock Vawr / [No. 2 Rhondda] - 85°23 480 997 17°8 1°46 Difference i "45 77 / 32 26 15 / No.2 Rhondda - 91°78 513 319 79 4°47 91°66 4°85 349 18°9 412 ee eee Misano are: : Difference - ad "13 28 30 10 35 Three Quarter {of Monmouthshire] - 87:81 5°09 710 v3 2°09 e ft 89°64 4°37 5:99 20°5 — Difference - : 1°83 "72 i Be 3°2 — Graigola - - . - 92°73 4°64 2°63 200 — "am is Gg 91°70 4°80 35 1971 5°37 , Difference - - 1°03 16 97 9 — E ssi

Greatest difference observed in this Table,

Se ee Ne

Different Samples From Tiite Same Seam, 41

Vein "Ge He : Ne C/H Fuel

lo |O&N°/. ratio, ratio. Big [of Monmouthshire] 89°65 4:37 5°98 20°5 ap + - 90°58 5°39 4°03 16°8 —

Difference - - 93 iIG Opa 195 oil

Tregloin - - - 93°79 3°67 254 25°6 17°8

. St AD, Koil BBITB 3°59 2°63 26'1 171 Difference - - 'Ol '08 '09 9) a7 Red [of the Neath Valley] 93-26 3°89 2°85 24'0 12°6 -S 92°74 3:96 330 23:4 12°9 2 % - 92°48 4:03 3:49 23-0 15°6 Maximum difference "78 14 64 10 30

Red [of the Neath Valley] 93°56 3°48 2°96 26°9 " " - 93°42 3°39 319 27°5 10°1

Difference - - 14 09 28} 6 —

Red [of the Neath Valley] 93°32 3°84 2°84 24°3 14'6

Difference - - "76 05 "api 6 2

Red [of the Neath Valley] 93°02 4:27 iat fl 21'8 12°7 ; j 3°50

" "

Difference - "44 36 '79 19 a7

Greatest difference observed in this Table.

The greatest differences observed in the two cases are therefore :—

(1) Different parts of the same vein :—

C 2/5 TE iseeOce,N "5 C/H ratio

Maximum difference - - 2°97 44 9°34 20 Mean of max, differences e 1°67 19 1:76 oF

42 The Coals Of South Wales.

(2) In same vein and pit but different samples and sometimes different analysts :—

C °/5 H°%, O& N°. C/H ratio

Maximum difference - 2 2°50 1°02 2°25 41 Mean of max. differences - 81 "31 "89 1°46

From the above data it will be seen that it is impossible to lay down on a map the composition of the coals with minute accuracy, and that the exact limits of anthracite, steam-, and house-coals is still indefinite, from a chemical point of view. It is quite possible that some of the early analyses may be inaccurate, for when charcoal-furnaces only were available for making combustions, the labour and difficulties must have been great. It should also be borne in mind that, in many cases, no details as to the collection of the samples are available, so that it is possible that the analyses in some cases represent a part of the vein only, and not the average composition of the whole thickness,

Chapter Vi.

Comparison oF Dirrerenr Seams in THE Same Locarrty. By W. Potrarp.

It is frequently the case that the lower the vein, in geological sequence, the more anthracitic it is. This rule, if proved to be universally correct, would be a point in favour of anthracitisation having been due to a cause operating from beneath. Also it should be possible, if the composition of the upper veins were known, to predict what the approximate eae of the lower veins would be. To test these points

the following table of analyses of different veins from the same

pits has been prepared, giving the approximate distance between veins, composition of the pure coal, C/H ratio, and fuel-ratio.

Distance Ts between xen Secs Nel ere i inels Vein. veins in C/o H/o ais ratio. ratio yards, Charcoal - -) 8£56 657 887 .19°9 2°10 Black - 87°49 poo eke O4 174 89°27 5°60 5:13 15°9 2°87 47 ) 93°91 3°70 2°39 Q5°4 15°4 21 Peacock 2 a 94°02 3°96 2°30 23°7 12°9 Four Foot - - 93°77 4°64 1°59 20'2 7°92 Peadiyiirya; - 92°93 491 2°16 18'9 5°16 54 to 70 : Nine Foot - - 91°89 4°59 3°54 20°0 6°03 Red — - B77 497 7°26 uly 2°22 Three Quarter - 86°63 5°13 8°24 169 1:95 page= apn 88°30 5°45 6°25 16°2 77 ; 88°61 5°29 6°10 16°8 2-3 50 Oldie 87°93 5°30 677 16°6 2°18 Graig - - - 92°57 4°72 271 19°6 512 151 to 210 " Two Foot Nine - 94°11 4°19 170 29°5 8'06 12 to 22 Four Foot - 92°74 3:96 3°30 23°4 8°75

The Coals Of South Wales.

"Distance O&N C/A Fuet oa between v uel~ Vein, veins in C°/o H®/o °/, ratio. ratio. yards, /

Big or Stanllyd — 94°21 3°75 2°04 25'1 16°4 93°82 3°81 237 246 16°2 48 / Middle an 94°31 3°64 205 25°9 18°1 ! Elled - - 84°42 5°48 =10°10 15'4 5 to 11 P Big? ee cer. ve 87°14 6°49 6°37 134 — 8 to 12 (Top of) Three 89°81 511 5°08 17°6 2°99 Quarter Three Quarter - 86°25 5°90 7°85 46 — 83 to 99 6) h bee xe lope a 90°74 5°23 4°03 174 3°40

No. 2 Rhondda - 93°58 4°05 2°37 23°1 12°1 Lower - - 93°71 3°69 2°60 25'4 12°4

Four Foot - - 88°51 5°02 6°47 17°6 2°56 88°80 5°36 5°84 16°6 2°30 Yankee - - ; 8812 5°57 6°31 158 2°24 ) Yard - - - 87°22 5°49 7°29 15°9 2°20 ] : Upper Four Foot - 90°92 4°51 457 202 — Ras-las - - 90°87 465 448 195 — Sane ae Graig. - a1 4 91°66 4°71 3°63 19°5 410 . 151 to 210 Two Foot Nine - 93°35 4°15 2°50 22.5 796 12 to 22 Four Foot - 9186 3°93 421 23°4 842 ie 23 to 35 Bix Foot 9. "s 92°73 3°95 3°32 23°5 7°31 Big? sf we oe 93°17 2°12 471 43°9° — a) Peacock . 5 93°94 3°77 2°29 249 15°4

See Note on p. 53.

a

rN NS ee a a ale eT

oe

DIFFERENT SEAMS IN THE SAME LOCALITY. A5 so rei etween ce He O&N C/H Fuelveins in Fr °/s ratio, ratio. yards. Six Foot - : 93°63 4:01 2°36 23°4 ' 49 Nine Foot - - 92°65 3°96 3°39 23'4 10°7 Red - 2 z 93°03 3°51 3°46 26'5 119 Bee (es - 93°92 3°55 2°53 26'5 19°0 94°49 3°67 1°84. 25'8 20 to 35 Brass. - - - 93°39 3°66 2°95 25°5 18°0 93°80 3°16 3°04 29°6 Big - : 93°37 3°43 3°20 27°2 17°5 Brass - e 93°70 3°90 2°40 24°0 14'8 Big 4 - 87°81 5°12 707 17°2 2:03 5 to 14 Three Quarter - 87°20 510 7°70 Van 2°05 54 to 59 Meadow - - 87°16 5°42 742 161 1°95 ae Yard - 2 90°53 4°98 4°49 18'2 3°32 39 g Cae David - : 87°99 5°64 6°37 15°6 1°91 90°78 5°13 4:09 Wey 3°04 Duffryn - - 89°75 4°92 5°33 18°2 3°29 Lower Six Foot - 91°25 4°84 3°91 18°9 3°96 38 to 43 Nine Foot - 91°37 4'93 3°70 18°5 3°99 Four Foot - Z 85°20 5°40 9°40 15'8 2°27 Nine Foot - a 86°30 5°34 8°35 16°2 2°29 59 Cribbwr : 87°50 5°15 Wea WO 2°46

Penyfilia or Five 91°66 4°87 347 18°8 439 Foot 2 88°66 6°03 5°31 ea 2°84 Six Foot - 90°75 4°73 A°5Q 19°2 3°93 : 13 Three Foot. - e 91°46 5°02 3°49 18°92 4-08 9:

46 THE COALS OF SOUTH WALES. Distance O/H Fuel ae between 4. 1 O&N / "ue Vein. veins in C/o H°/o Head ratio. ratio, yards. Forest - - 86°38 5137) 58/25 16°1 a a Graigola — - / 92°73 4°64 2°63 20°0 91°70 480 350 1911 5°37 hy Red z 92°48 4:03 3°49 23°0 15°6 333 ) Big - 93°96 3°74 2°30 25'1 17°2 Eighteen Foot 93°52 3°82 2°62 245 13'3 Cornish - 93°83 3°95 339 23°8 13'8 ; 30 to 35 Nine Foot - 93°79 3°86 2°35 24°3 15°0 Big - - 90°58 5°39 403 168 Three Quarter 87°81 5°09 710 Wy 2°09 89°64 4°37 5°99 20°5 Black - - 8824 24 6°52 16°8 191 90°74 4°84 4°42 187 Lower Trichwart - 94°1 36 2°3 26°1 18°6 about 17 Lower Pumpquart 93°00 3°68 3°32 25°3 183 poe —— ss x ' Drap 92°59 4°54 2°87 20°4 83 Green - - 93°98 3°88 214 24°9 13'9 — 9B 77 3°74 249 951 14°5 Blatog 2. 83°63 528 11°09 15'8 180 36 to 38 Curly - - 85°93 5°92 815 145 165 14'to 17 Bodor - : fee ' 85°69 581 850 14°7 1'97 Hughes - 77°40 467 17°93 166 '94

Different Seams In The Same Locality, 47

On going through this Table it : mately in about half the cases the lower the vein the hig

Distance ith between (/ oj, O&N C/H Fuel veins in CP /o H°/o Hee ratio, ratio, yards, Big - 95°15 211 2°74. 45'1* Peacock - : 93°73 3°29 3°05 29°] Ward's Fiery 94°68 4°23 1°09 99-4 Graigola — - - 90°14 503 4°83 17°9 3°82 Four Foot - 92°03 4°70 3°27 19°6 5°60 Five Foot — - - 92°17 4°63 3°20) 20°0 5°87 Four Foot - — - 91°81 399 4:20 23°0 Big : d 3 93°88 3°65 2°47 257 See Note on p. 53.

will be seen that ee er the

carbon. Of the remainder several show the reverse, while in others the carbon varies irregularly. The same result approximately is observed in the carbon-hydrogen ratio,

The only chance of ascertaining exactly how far the rule holds good, and what the rate of variation is, would be to have a larger number of specimens analysed than have been available up to

the present.

48 : wrt

CHAPTER VII. CLASSIFICATION OF COALS. By W. Pouvarp.

'The more recent papers on this subject are :—

C. A. Seyler, 'Chemical Classification of Coal, Proc. S. Wales Inst. Eng., Vol. XX, p- 483, and Vol. XXII, p. 112.

'Report on the Operation of the Coal Testing Plant of the US. Geol. Survey," Professional Papers, No, 48, Part I, p. 156.

heal

S. W. Parr, ' The Classification of Coals,' J. Am. Chem. Soc., Vol. XXVIII, 1906, p. 1425, and Colliery Guardian, Vol. XCIT, 1906, p. 1209.

F. F. Grout, 'The Composition of Coals, Economic Geology, Vol. II, 1907, p. 225.

The Pennsylvania System (F uel Ratio) will be found in Report M.M. of the second geological survey of Pennsylvania.

In Mr. Seyler's paper, on pp. 483-491, a good résumé of the older classifications is given. is own classification, though not verfect, is one of the best, if not the best, so far available. It is fans on the percentage of hydrogen and carbon, calculated on the pure coal. The hydrogen determines the genus and the carbon the species. The following table, taken from ' Analyses of British Coals and Coke' (p. XV), gives the system :—

(snourungiq (snourmny1q (snouTUIngIq "'que0 ed -e.red-qug) -0Y}10-qng) ~849Ul-qnug) (snosovmo0qao-qng) eyloviyjue F Japun ussoipAP Si sPOVIIUB-Opnesg oloBv1yQUR-opnesg 9}lOBIYAQUe-Opnasq oqlovIyyuR-opnesg "0710, snue+) d1Z1IovlyqUy (snourum91q (shoatuingiq (shout 41q 'queso red ~ered-qng) -04910-qnq) ~BJauI-qng) (snosovu0g.1Rd-049.10) 'sotoads snosovuo0gies-opnesg

(ou919) (ezepq) SNOMIMDIT-qng

(snourwmngiq -ered-qug) snourum4yiq-qug

(04940) (eqezy) "SROIIUST]

snourwmngiq-eile g

SROT}IUSI[-19q

Sl—08

(snourumngtg -ered-19q) SnOUTUINITq -19g

shosdvu0gIBd-Opnesg

snosdvuoqieo-opnesg

(snourmin}1q -04}.10-qng) SnoulUIngiq-qug

(snoutungiq "BJoul-qus) SNOUTUINGIG-qng

SNOULWIN}Lq -O44IO

Snoutuingtg-B{0T

(snourumngiq

-OY}.10-107) snourMin4ytgq-18q

(snourwmin4iq -BY9UI-19q ) snouluingtq-19q

satoeds snosoruoqieg

OIFTOVAYAUR-1MEg

(snouruinytq "TULES-OY JIC) sotoeds SNOUTTINAIG-TuTag

G.F — 0. wosor1pATT Snus+) snOsoVUOgIVD

'que0 red 0.G6—¢.7 uoso1pAH snus) SNOUIUUINIG -THag

(sotoads SNOUTHINIIq-Gpnesq )

'que0 13d

8-G—0.¢ uasorpsTT snuex) snoulmngig

'que0 rod §.G¢ I9A0 UasoIpATT snug) SNOULUIN}Iq-18q

'quo Jed ¢.¢6 08—F¥8 0-78—0- L8 0-L8—0:68 0-68— 6-16 - 16—€-86 I ERS -OUJIO -BIIT -CIB -ouIO -B9IN 'NOdUVD "SNOLLINODI'T "SQONIWOALIG 'SNODOVNOdUVD "'OILIOVUHING

'wog fo wornoyissnng s waphag

N.B.—The various genera are ar

to the hydrogen.

ing

d horizontally

Column 1 vertically accord

in

h genus are arrange

ranged

The species in eac

according to the carbon,

50 Tite Coals Of South. Wales.

The United States Geological Survey have recently dealt with methods of classification of coals, but do not mention Mr, Seyler's paper. The classification finally adopted by them is founded on the proportion of carbon to hydrogen, and the limits proposed for the different classes of coal are as follows* :—

C.H ratio. A Graphite - - : : 2 - © to? B) one P 2 to 130 Cs Anthracite ' 2 2 i 130 to 126 D Semi-anthracite - . - %s : 126 to 723 E Semi-bituminous - - - 123 to 20 20 to 17 meh, FA Hele 17 to 14°4 H Bituminous - . é - 2 144 to 12°5 B/S ae 125 to 112 4) Lignite - - - - - - : 1l2to %9°3 K Peat - - - - - - - 99°3to 7 L Wood (cellulose) — - s z J 5 9

*This system has also been discussed by B. Renault, 'Sur quelques Micro-organisms des Combustibles fossiles. Bulletin de la Soc. de Uludustrie Minévale, Sér. 3, t. xiii, 1899, and t. xiv, 1900. Also separately published.

The classification founded on the fuel-ratio, that is, on the relation of coke to volatile matter on coal free from water and ash, as adopted by the Pennsylvania Geological Survey, may be summarised as follows :— i

Fuel-ratio,

Anthracite - - : - - - . 12 and over

1. M it .7 se mi-anthrax ite : - : . - 8 to 12 Semi-bituminous " - - - - 5to 8 Bituminous - . : Oto 5

ry 4 fe . . his sy stem has been found to be unsatisfactory, except for thesanthracitic and semi-anthracitic coals,

Prof. Parr has recently proposed a classification, based on the

factor VC x TE. where VC represents the volatile carbon unassociated with hydrogen, and C the total carbon in the coal. In the bituminous and lignitious classes " inert volatile" (volatile matter less volatile carbon) is made use of for the

purpose of further discrimination, In the following table the proposed limits are given ;—

CLASSIFICATION OF COATS. on

t 0 VO x Inert Volatile,

Anthracite # - 4 and under' Semi-anthracite Z ° 4to 8 Semi-bituminous : 10 to 15 a Bituminous A - : 2 20 to 32 5 to 10

Bi ak - : 20 to 27 LO to 15

Cee : : 32 to 44 5 to 10

Die z - 27 to 44 10 to 15 Black Lignite - - - 27 and over 16 to 20 Brown Lignite - - - 27 and over 20 to 30

A further suggestion is made to express " Intrinsic Value" or "Relative Merit" of coals as fuel, assuming the true fuel-value of a coal to depend on the total carbon, available hydrogen and sulphur. The method is best shown by an example, for a coal composed of

Carbon - - - - - 78°31 per cent.

Hydrogen - - - - : 4°31

Salph ues. baat - os ON 3. 83°52

eee LOO ; Hence the " Gross Coal Index " is or 120. This means

that with this coal 120 lbs. will be required to make 100 lbs, of actual fuel.

Apparently the most recent classification is that of Professor Grout. It may be briefly stated to be based on fixed carbon for the anthracites to semi-bituminous, and on fixed earbon and total carbon for the bituminous and lignitious coals, Apart from a suggested diagrammatic representation of coals, the Biowite table shows the classification proposed, All data aro calculated on coal free from ash and water :—

Fixed Carbon, Total Carbon, Graphite. 4) vines re over 99 Anthracite - - - over 93 -- Semi-anthracite - - - 83 to 98 Semi-bituminous - - - 73 to 83 High grade bituminous - - 48 to 73 82 to 88 Low grade bituminous - : 48 to 73 76'2 to 82 Cannel - - - - - 35 to 48 76°2 to 88 Black Lignite - - - - 35 to 60 73°6 to 76°2 Brown Lignite - - - 30 to 55 65 to 73°6 Peat and Turf - - - 2 below 55 below 65 Wood - - S ; — —

52 The Coals Of South Wales.

The data on which the various classifications here mentioned are based are therefore :— (1) Percentage of carbon and hydrogen, calculated on pure coal, (2) The relative proportion of carbon to hydrogen—that is, the C/H

ratio. (3) The relative proportion of coke to volatile matter—that is, the fuel-

ratio, ; 100 : a 4 . (4) Volatile carbon x — ea: ith due consideration of " inert volatile." total carbon (5) Fixed carbon with due consideration of total carbon in pure coal.

Before comparing the value of these olassifications for the present purpose 1t should be stated that the following remarks apply only from the anthracite to the bituminous or er-bituminous coals, as lignites do not occur in this coalfield, a though in one or two cases coals nearing the lignitious class have been met with.

The volatile matter and fixed carbon estimations have already been shown to be liable to considerable errors, so neither of these figures should be taken for purposes of classification if better are available. Mr. Seyler has shown also that the hydrogen and volatile matter are closely connected, so that any system in which volatile matter, and hence coke,are made use of,together with total carbon, practically amounts to classifying on carbon and hydrogen. And as carbon and hydrogen can be estimated with great accuracy, it seems more rational to use them asa basis in classification, although the proximate analysis of a coal is, in most cases, sufficient to discriminate between anthracite, semi-anthracite, and semi-bituminous coals,

The choice of classification for the present purpose therefore lies between Mr. Seyler's and the carbon-hydrogen ratio. As the object in view is to show the progressive change in character of the coal in this coal-field, and as this is most obviously shown by figures on a map, the preference falls to the C/H ratio. This ratio has the disadvantage that there is necessarily a certain amount of overlapping in the various groups and species, but it has the advantage of combining the two constituents, which can be simultaneously and directly estimated with a considerable degree of accuracy, and of avoiding the necessity of recalculating on to the pure coal, when, as has been shown, considerable errors may be introduced through the oxygen having to be taken as the difference of the sum of all other constituents and 100. The only serious causes of error likely to occur in the C/H ratio are the presence of carbonates or rae minerals in the coal, both of ae would probably be observed and the carbonate, at any rate, corrected tor. The C/H limits as proposed by the United States Geological Survey would require to be modified for this coal-field, as there are, for example, many good anthracites with a C/H ratio of less than 26. The limits 'as marked on the maps do not designate a hard and fast line, and are not intended to imply, for instance, that all coals on one side of, say, a line marked 23 are anthracites, whilst all those on the other are semi-anthracites, &e., but are only intended to illustrate the general distribution of the different classes of coal.

Classification Of Coals. 53

In the following table the C/H limits theoretically possible for the various coals of Mr. Seyler's classification are given, also the limits observed for the various analyses here published, arranged on the sime classification.

All available ultimate analyses have been made use of, provided locality and vein could be identified, as it appeared fairer to do this than to select analyses. In a few cases where an ultimate analysis was not available the proximate has been given. Where there appears reason to think an analysis is doubtful or does not represent a fair sample of the vein, attention is drawn to the fact in a footnote.

Anthracitic Genus.

Species. aes oe Observed limits. cae Ortho-anthracite - - - 23°3 and over} 23°7 & over 54 Sub-carbonaceous - 22°8 and over, 23 to 29:9 17 Sub-metabituminous- 22°25 and over; None observed Pseudo- / Sub-orthobituminous 21°75 and over) 29°08 1 Anthracite Sub-parabituminous - 21'0 and over Sub-metaligmition - 20°0 and over} None observed Sub-ortholignitious - 18°75 and over

Carbonaceous Genus.

Semi-anthracitic - : : a 2077 at 21°3 to 23°35 9 Ortho-carbonaceous 2X0} — Ose 20°6 to 23°0 10 Sub-metabituminous - : 19°7 —— 22°8 20°5 to 20°9 3 Sub-orthobituminous. - : 19°3 — 22°2 20°31 1 Sub-parabituminous— - - 18°7 — 21°75

Sub-metalignitious - - 21:0 — 178 None observed Sub-ortholignitious — - - 16°6 — 20°0

Semi-bituminous Genus.

(Anthracitic)- + - 187— 212%) 20:2 1 Ortho-semibituminous- - -, 182— 207 18°4 to 20°4 25 Sub-metabituminous - -° - 178— 203 18°2 to 20°2 8 Sub-orthobituminous - — - 174— 19°7 17°7 to 18°8 3 Sub-parabituminous - - -, 16'8—- 19°3 17°8 to 18'2 2 Sub-metalignitious - -/] 160—187 None observed

Sub-ortholignitious - - 150 —17°8 16°6 1

Two cases are not included here (Nos. 167 and 175) as the hydrogen appears abnormally low, namely 2°12 and 2°17 per cent. With the exception of Ne. 169, in which the percentage of hydrogen is 2°11, no other coals, even in Pembrokeshire, show less than 3°0 per cent. of hydrogen. The C/H ratios are respectively, 43°8, 43°0 and 451. Had they contained 3 per cent. of hydrogen the C/H ratios would have been 31°0, 31:0 and 31°7. They were communicated in MS., so it is possible a copying mistake was made, or they may have been selected for some purpose or investigation unknown.

54 Tite Coals Of Soutit Wales.

Bituminous Genus.

(Anthracitic) - - - - 16°1 — 19°0 ? 17°6 1 Pseudo-bituminous : -|157—186 17:4to 182 3 Meta-bituminous - - 15°3 — 18°2 15°7 to 17°9 8 Ortho-bituminous - Z - 1150 — 178 15°2 to 17°6 21 Para-bituminous - - : 1145 174. 19" 154 fo 16'9 8 Meta-lignitious — - - - -/ 1383 —168 152to 15'8 2 Ortho-lignitious - . - -1/129—160 14°6 1

ncn a ee

Per-bituminous Genus.

(Anthracitic)- — - - - - 13°99 1— 16°22 k

(Carbonaceous) - - - - 161 and less None observed Per-metabituminous — - - -|15°7 and less 13°4 1 Per-orthobituminous - - - 15°3 and less 13°4 to 14°7 5 Per-parabituminous — - - - 15°0 and 12'9 to 14°7 ° 4 Per-metalignitious . - - 5 andless I w Per-ortholignitious - : - 13°8 and less § None observed

Summary of observed limits for the various Genera.

Anthracitic genus - - - - 22 and over

Overlap 1°35° Carbonaceous genus - - - 20°3 — 93°35

Overlap '1

Semi-bituminous genns_ - - - 166 — 204

Overlap 1°6 Bituminous genus - . - - 146—182 .;

Overlap '1 Per-bituminous genus —- - - 19°9 — 14-7 é

For example, a coal with C/H ratio between 22 and 23°35 might belong to either the anthracitie or carbonaceous genus.

Out of the 203 analyses available 12 are only proximate analyses, so it is impossible to name these on Seyler's or the C/H classifications. Of the 191 where it is possible to name on these classifications, the C/H ratio shows, on the limits adopted by the United States Geological Survey :—

Anthracites rs F ; s ' 33 Semi-anthracites : : : : - 42 Semi-bituminous : . - og ite - 29 Bituminous I, - - 3 - : 44. Bituminous IT. ' . - - 38

Bituminous IIT. - + ib

ee ee

CHAPTER VIII. EXPLANATION OF THE IsO-ANTHRACITIC CHARTS (PLATES 8 To 7), By A. STRAHAN.

The object of these charts is to show areas of equal anthracitism in each seain or group of seams. The positions of the samples on the analyses of which the charts are founded are indicated by numbers corresponding to those in the table on pp. 14-27,

The degree of anthracitism of each sample is expressed by the factor representing the relation of carbon to hydrogen, i.e. the C/H ratio, that factor being more suitable for the purpose than any other, for the reasons explained on p. 52. The figures in the table which give that relation range from 13 to more than 31, and for convenience the lines corres ponding to the numbers 14, 17, 20, 23, 26, and 29 have been Sluciett for illustration of the iso-anthracitic areas on the charts. The iso-anthracitic line 17, for example, is drawn through all those localities in which it is calculated that the C/H ratio would equal 17.

The space between lines 14 and 17, in any one seam, may be tiniest as corresponding to the area in which that seam has the character of house-coal, but begins to assume that of steamcoal, that is belongs to the Bituminous Genus of the Table on p. 54; while that between lines 17 and 20 includes the passage into steam-coal, and steam-coal, that is the Semi-bituininous Genus of the Table. Lines 20 to 23 include steam-coal of the Carbonaceous Genus. Line 23 marks the oncoming of anthracites, and from line 24 (not shown on the charts) upwards the coals may be regarded as true anthracites.

The iso-anthracitic lines have, of course, no relation to the outcrops of the seams. In fact, a line is sometimes continued a little beyond the area in which the seam to which it relates exists, or even beyond the margin of the coal-field, where the evidence obtainable in the coal-field suftices to indicate the position it occupied before the coal-field was reduced to its present dimensions by denudation.

Plate 8.

The chart forming this plate is founded upon analyses of the lowest veins, namely, those which occur below the datumline of Plate 2. Taken from east to west, the group includes the following seams :—

Old Coal. Middle Vein.

Meadow Vein. Lower Vein.

Cribbwr Vein, Trigloin Vein.

Four Feet Vein (Morfa), Lower Pumpquart Vein. Four Feet Vein (Clyne Valley). Lower Trichwart Vein. Yankee Vein. Lower Level Vein.

Three Feet Vein (Clyne Valley). Timber Vein. Brass or Peacock Vein,

56 The Coals Of South Wales.

The samples for analysis were obtainable from the margin only of the coal-field, none of the veins being accessible at present in the interior. The seams as a group lie on the same horizon, near the base of the Coal Measures, and are included in a thickness of about 500 feet of measures. The Timber Vein nay correspond to the Stanllyd, which is taken as the datum-line in Plate 2,

The iso-anthracitic line 17 is determined by the analyses of the Old Coal and Meadow Vein towards' the east, and by analyses of the Cribbwr Vein and the Clyne Valley coals in the South Crop. The direction in which the anthracitic character develops is foreshadowed by the analyses of both the Old and the Meadow seams, but evidence of the position of line 20 is wanting. The position of line 23 is indicated by analyses of the Brass Vein, and those of lines 26 and 29 are fixed by a series of analyses of the Brass, Trigloin, Middle, Lower, Lower Trichwart, and Lower Pumpquart Veins. The Pembrokeshire analyses lie near, or on the higher side of, line 29, and correspond to, or slightly surpass, the highest stage of anthracitism reached in Carmarthenshire.

Plate 4.

This chart is founded on analyses of the vein which, in different arts of the coal-field, passes under the following names :— he Black or Rock (eastern part), Ras-las or Nine Feet (East

Glamorganshire), Nine Feet or Big (North Crop on the borders of Glamorganshire and Brecknock), probably the Stanllyd and Carway Big (Carmarthenshire), note possibly the Timber Vein (Pembrokeshire). This coal-seam being more widely recognisable than most others, has been selected as the datum-line in Plate 2, and is more fully illustrated than the rest. in the analyses.

The iso-anthracitic line 17 is well determined in Monmouthshire, but, so far as regards the South Crop, is founded only on an analysis of the Nine Feet at Morfa (No. 27), of the Nine eet at Llynfi (No, 23), and of the Nine Feet at locality No. 9. It coincides approximately with the line 17 in the underlying seams (Plate 3).

The iso-anthracitic line 20 follows a parallel course, but is bent north-westwards to accommodate an analysis of the Ras-las at Dowlais (No. 22), quoted by Dr. Perey, Not improbably this bend would disappear, or be modified, if further analyses east of locality 22 were available. a

Line 23, so far as it is determined by analyses of the Nine Feet at Hirwain (No. 24) and the Nine Feet of ocality 19, follows a normal course, but its westward continuation is not proved,

Line 26 is founded on a series of analyses of the Big, Nine Feet, or Stanllyd Vein of the anthracitic region, The bend in it may be due partly to experimental error in analysis, and have little significance.

Line 29 is not reached in the Big or Stanllyd in Carmarthenshire, but its position is indiana by analysis No. 13, and it is

——

EXPLANATION OF PLATES. bY

touched at Hook (No. 198) in the Timber Vein, which may correspond to the Stanilyd.

The Green and Drap Veins, which lie 25 and 107 yards respectively above the Big Vein, are also shown upon this chart. In the Green Vein the positions of lines 23 es 26 are determined at localities 190 and 146, and that of line 20 in the Drap Vein at locality 145. The lines 20 in the Drap, 23 in the Green, and 25 in the Big Vein (Nos. 12, 144) approximately coincide, while line 26 in the Green lies a mile north of line 26 in the Big Vein. This, of course, means that in any one vertical section the Drap would be more bituminous than the Green and the Green than the Big, in accordance with the rule mentioned on p. 2. But, on the other hand, on comparing Plate 4 with Plate 3, we find that the line 23 in the Big or Nine Feet Vein lies six miles south of the line 23 in the Brass Vein, which is about 20 yards below, and again that the line 26 in the Big or Nine Feet lies distinctly south of the line 26 in the lower veins. This means that the Big in any one vertical section would be more anthracitic than some of the seams below it. The rule referred to is therefore not universally true.

Plate 5.

A group of veins which lies not far above the datum-line of Plate 2, and includes the Red, Elled, Big and Three Quarters of Monmouthshire, is illustrated in Plate 5.

In the Three Quarters, or lowest vein of the group, the isoanthracitic line 17 is founded on several analyses, and is not far from coinciding with the line 17 in the Black or Ras-las Vein, thirty yards below (Plate 4). An analysis, however, at Blaina (No. 92), on the authority of Dr. Percy, gives a carbon-hydrogen factor of 14'6, which indicates that the coal becomes more bituminous in a north-westerly direction. Taken by itself, this exception to the rule that the seams become more anthracitic towards the north-west might not have had much significance, but it acquires importance when taken in connection with the analyses of the Red, Elled and Big, the overlying members of this same group of seams.

The Red, Elled and Big Veins are illustrated on the same plate. In these veins the position of the line 14 is determined by two analyses, both quoted from Dr. Percy, one being the Big Vein of Blaina (No. 29) and the other the Elled Vein of Blaina (No. 90). The line 17 as determined in those veins coincides approximately with the line 17 in the Three Quarters, and though the lines 14 do not coincide they agree in showing that the upper as well as the lower vein of the group becomes more anthracitic eastwards and southwards. This exception to the rule appears to be local and confined to this group of seams.

Plate 5 also illustrates what is sometimes known as the Aberdare series of seams. This series includes the Two Feet Nine, the Upper Four Feet and the Six Feet. Further west some seams well known in the Vale of Neath occupy about the same horizon. As shown in Plate 2 these Aberdare and Vale of Neath coals

58 The Coals Of South Wales.

correspond collectively to the Monmouthshire group illustrated

in Plate 5, though the correlation of individual seas is open to

doubt. The iso-anthracitic line 17 in the Aberdare Four Feet

seam is determined by an analysis (No. 87) of a sample from

the Ebbw Vale Iron Works, quoted from the Admiralty Report.

It lies a short distance only from the line 14 in the Elled and

Big Veins as shown on the same plate. The anthracitic character,

however, increases westwards in the Upper Four Feet, for a- nuinber of analyses extending from Dowlais to near Maesteg - fixes the position of line 20 at a distance of about 8 miles west

of line 17. The loop in the line 20 is drawn to accommodate a

single analysis (No. 88) of coal from Hill's Plymouth Merthyr

quoted in the Admiralty Report and giving a carbon -hydrogen

ratio of 22:1,

The Aberdare Six Feet Vein lies below the Four Feet and should, at any one spot, be more anthracitic; accordingly the line 20 in the Six Feet runs about 2 miles south and west of the line 20 in the Four Feet. The lines 23 in the two seams coincide, but in the Two Feet Nine seam, which lies above the Four Feet, we have to travel a mile and a half further on before we reach the anthracitic degree represented by line 23. These facts are in accordance with the rule that the lower seams are the first to become anthracitic.

Three lines are shown in the Vale of Neath seams. They are founded on analyses of the Four Feet and of the Eighteen Feet, which lies 10 to 14 yards above the Four Feet seam. Both coals are placed on the market as anthracites, this part of the Vale of Neath being commonly regarded as lying on the margin of the anthracitic region.

The evidence furnished independently by these seams indicates that the iso-anthracitic lines trend north-westwards, as though there were a local anthracitic centre near Glyn Neath. This trend is not observable in the underlying seams (Plates 3 and 4), but is maintained in an overlying seam, the Red Vein, which is uso shown on Plate 5. Though there is no doubt that further analyses would show that the lines soon resume their normal westerly trend, yet this agreement in an unusual direction in so many veins, taken as they were independently, is too pronounced to be ignored. 'It indicates that there are local peculiarities in the distribution of the anthracitie character in certain seams or groups of seams, which are difficult to explain on the supposition that the seams were originally alike, but were subsequently anthracitised by one common cause,

The Red Vein here referred to is not to be confused with the Red Vein of Ebbw Vale (compare Sections 7 and 10 in Plate 2). It is recognised as a workable seam from the Dulais, a tributary of the Neath, to near Ainmanford, and is regarded as an anthracite, but as approaching a steam-coal in places. The analyses enable the iso-anthracitie lines 23 and 26 to be fixed with some precision from Dillwyn in the Dulais valley to Cawdor Cwmamman. ;

On comparing the Red Vein with those below it, it will be

Explanation Of Plates. 59

seen that the line 26 in the Red Vein approximately coincides with the line 23 in the Eighteen Feet Vein, and is south of the line 23 in the Cornish Vein. This indicates that the Red Vein becon.es anthracitic in a region where the veins several hundred feet below it have not yet assumed that character. Here again we have an exception to the rule that the lower seams are the earlier to become anthracitic, and a further illustration of the fact that some seams have a certain individuality in their behaviour as regards their assumption of the anthracitic character.

A single analysis (No, 124) of the Lower or Welsh Vein of Cwm Clic, quoted from Percy, has been inserted in this chart. The carbon-hydrogen ratio is 254, which indicates that the seam is more anthracitic than the Red Vein, though it lies above it. Confirmation of this is desirable.

The Drap and Green Veins lie above the supposed equivalent of the Nine Feet, and therefore correspond approximately in position to the Vale of Neath and Aberdare seams illustrated in the plate. Their composition confirms the supposition os mentioned, that the normal trend of the iso-anthracitic Ines 1s soon resumed west of the Vale of Neath.

Plate 6.

Plate 6 shows the iso-anthracitic lines in the seam known in different areas as the Tillery or Red Ash, the Rock-fawr, the Brithdir, the Pen-y-graig or No. 2 Rhondda. It may be compared with the chart of the Ras-las Vein in Plate 4. In both the anthracitic character develops steadily north-westwards, and, except for irregularities in the curves, which are drawn to suit certain analyses, and which might be modified if the series of analyses were more complete, there is a fairly close coincidence of lines 14, 17 and 20 in the higher seam with lines 17, 20 and 28 in the lower seam. This relation of the lines gives data for calculating the vertical rate of decrease of anthracitisation for certain localities. Thus in Monmouthshire a decrease of 3 (from 20 to 17) in the carbon-hydrogen ratio oceurs in a vertical distance of $52 feet, giving a rate of 1 in 284 feet. But near locality No. 179 in the Brithdir, and locality No. 7 in the Ras-las Vein, the vertical distance is 1,850 feet, and the decrease of 3 (from 23 to 20) in that distance gives a rate of 1 in 450 feet. Again at Bronbil (locality Nos. 55 and 59) the mean of two Admiralty analyses gives a carbon-hydrogen ratio of 169 in the higher vein, while at Morfa (locality No. 27) the ratio is 16°2 in the Nine Feet Vein, about 2,600 feet below the Bronbil seam. Here, therefore, the higher and the lower seams are about equally bituminous, a state of affairs which probably prevails throughout the extreme southern margin of the coal-field.

The analysis of the No, 2 Rhondda Vein which lies nearest to E

60 Tiie Coals Of South Wales.

the anthracitic region is quoted from Perey, who gives the seam as the Upper or Pen-y-graig Vein of Cwm Clic. It fixes one point on ae line 23, but leaves us in doubt whether that line takes the north-westward trend which is observable in the Red and other veins of Plate 5. It proves, however, that the No. 2 Rhondda seam reaches the anthracitic degree indicated by the line 23 further south than do either the Red or the Cornish Four Feet Veins, and thus furnishes another exception to the rule that the lower seams are the more anthracitic. So far as this locality is concerned the rule is generally reversed.

On Plate 6 an analysis of No. 3 Rhondda Seam also is entered. It indicates that at Penrhiw (localities Nos. 125, 196) that seam is slightly less bituminous than the Forest Vein which lies about 77 yards above it. In the Graig Seam, of which we have two analyses, the line 20 agrees closely with the line 20 in the No. 2 Rhondda Seam, although the Graig Seam lies upwards of 150 yards below the No. 2 seam,

The Hughes Vein, which is also illustrated on Plate 6, forms the lowest and most important member of a group which includes also the Slatog, Curly, and Rotten or Bodwr Veins, and has been extensively worked from near Glyn Corwg to the western end of Gower. It lies from 450 to 500 yards above the No. 2 Rhondda Seam or its local equivalent.

A comparison of the lines in the Hughes Vein with thos2 of the No, 2 Rhondda Seam shows that the line 20 in the Hughes would, if prolonged, join line 20 in the No. 2 Rhondda, but that line 17 lies much closer to line 20 in the Hughes group than it does in the No. 2 Seam farther east. This implies that the change in character is more rapid in the west, a conclusion of which we shall obtain further evidence.

Plate 7.

The Mynyddislwyn, or Bedwas Vein, is well known as a house coal in Monmouthshire, but the analyses are too few to admit of more than an approximate determination of line 14. That line lies generally nearer the anthracitic region than does line 14 in the No. 2 Rhondda Vein (Plate 6), as was to be expected but apparently a local reversal of the rule occurs at locality 72, There the carbon-hydrogen ratio in the Mynyddislwyn Vein is 15°4, whereas in locality No. 123 the ratio in the Charcoal Vein, the Hae equivalent of No, 2 Rhondda, is only 12.9, according to the Admiralty Report. a1

As already explained, the Wernffraith, or Swansea Four Feet Vein, is taken to be the equivalent of the Mynyddislwyn Vein in Say Ha to the Graigola, or Six Feet Vein, which lies 250 yards below the Four Feet. The analyses enable us to trace the line 20 for some miles. It follows the same general direction as line 20 in the Six Feet Vein, but runs into it, and crosses it to the

Explanation Of Plates. Ol

west, the evidence for this being an analysis of Ward's Fiery Vein* (No. 104) quoted in the Admiralty Report,

That analysis gives a carbon-hydrogen ratio of 22°4, as compared with 17-9 in the Llanelly Fiery (No. 105) to the west of it, and with 191 in that vein (No. 101) to the east of it, although Ward's Fiery Vein lies 218 yards above the Llanelly Fiery Vein. The exact position, however, of line 20° towards the west must in any case be regarded as doubtful, inasmuch as it is founded on one analysis only.

The Graigola, or Six Feet Vein, is 270 to 350 yards above the Hughes Vein. The iso-anthracitic line 20, as determined by several analyses of the Graigola Vein, runs slightly north of the 'line 20 in the Hughes Vein for part of its course, and turns northwards towards the east so as to suggest the existence of a local anthracitic centre between Swansea Vale and Pontardulais, Combining this chart with that of the Aberdare Four Feet (Plate 5), we obtain the relative positions of two local anthracitic centres with a comparatively bituminous area extending northwards between them. Our information does not suffice to prove that either vein would show both centres, but it is likely that the Aberdare Four Feet would do so, for the north-westerly trend of the lines shown in Plate 5 is certainly replaced by a westerly or south-westerly trend a little further west.

An analysis (No. 122} of the Swansea Three Feet Vein is entered on this same chart. That vein lies 13 yards below the Six Feet, but appears to be slightly more bituminous than it, on comparison ot analyses Nos. 100 and 122.

The Swansea Five Feet lies between the Four Feet and Graigola (Six Feet) Veins, and 140 yards above the latter. The analyses are limited to a small area: two from the same colliery give a carbon-hydrogen ratio of 18°8 in the Five Feet Vein (No. 74) as compared with 1918 in the Graigola (No. 100), which gives a vertical decrease of °38 in 140 yards in the carbonhydrogen ratio, or 1 in about 1,000 feet. The position of line 23 is indicated by one analysis only (No. 76). The iso-anthracitic lines in the Five Feet Vein are not inserted on the plate for want of space.

The rate at which the bituminous character decreases northwards has been determined with great accuracy in one locality in this vein. Three sets of samples (Nos. 152—160) were collected with this object in view from three spots situated in a line running nearly north and south. Locality A (Plate 8), which yielded the samples 158, 159, and 160, was 520 yards

The Fiery Vein of Llanelly is well known to correspond to the Graigola or Swansea Six Feet, but "Ward's Fiery Vein" is the name given on old plans to the Llanelly, or Box Big Vein, which corresponds to the re Four Feet. The Fiery Vein of Oldcastle (Analysis No. 105), on the other hand, must be the Llanelly Fiery, inasmuch as the Llanelly Six Feet, or Box Big Vein, is *in the wind" at that colliery. ae:

G2. The Coals Of South Wales.

N. 11° W. of Locality B, which yielded the samples 152, 153, 154; Locality B was 1,310 yards N. 22° E. of Locality C which vieldod aie samples 155,156,157. The results are shown in the following table and in Plate 8 :—

Swansea Five Feet Vein.

Locality A. Locality B. Locality C. Carbon-hydrogen Carbon-hydrogen Carbon-hydrogen. ratio. ratio. ratio. Yop Coal - 21°10 20°81 18°98 Middle Coal - 21°15 20°89 18°77 Bottom Coal - 20°85 20°58 18°67 Mean - 21°03 20°76 18°807

These figures show that the change becomes more gradual as true anthracite is approached. Thus from C to B the rate on the mean values is one unit of the carbon-hydrogen ratio gained in 604 yards, while from B to A the rate is one unit in 1,813

ards, : The change in the part of the coal-tield from which these samples (Nos. 152—160) are taken is certainly more rapid than it is in the eastern part, but data for an exact comparison are lacking, no other opportunity having occurred of obtaining samples from the same vein at a series of suitable spots.

GHAPTER, IX. ORIGIN OF ANTHRACITE, By A. STRAHAN.

MusaeEr was the first to attempt an explanation of the variations in the composition of Welsh coals. He pointed out that coals of different qualities are associated with similar strata, that the coal only, and not the accompanying measures, is changed, and that there is no contact of trap-rocks to account for the phenomena. He found difficulty in the supposed growth of a wide variety of plants in a limited space, and concluded that " fermentation and the degree of temperature thereby excited during the period of transition—but not that of submersion—from wood or vegetable matter into coal,may . . . furnish the most rational clue to the mystery."*

De la Beche also sketched generally the distribution of anthracite, and wrote: "Taking the coal measures of South Wales and Monmouthshire, we have a series of accumulations in which the coal beds become not only more anthracitic towards the west, but also exhibit this change in a plane which may be considered as dipping to the S.S.E. at a moderate angie, the amount of which is not yet clearly ascertained, so that in the natural section afforded we have bituminous coals in the high grounds and anthracitic coals beneath."

He found nothing to lead him to infer that there was any original ditference in the coal, and attributed the anthracitisation to subsequent change. The change he believed to be due to the volatile compounds formed by decomposition ces carried off relatively greater proportions of the hydrogen an oxygen than of the carbon. The view that it was due to disturbance of the strata was, in his opinion, untenable, inasmuch as the Coal Measures at Merthyr Tydfil were not more disturbed than they were at Pontypool, nor at Hirwain than they were at Pyle. The bituminous coal of Vobster, moreover, near the Mendip Hills, was far more contorted than a great proportion of the anthracitic coal of South Wales. He concludes by referring to long-continued high temperature as capable of effecting the change, and points out that if a portion of the coal-area was depressed below the other parts, and thus brought more within the influence of internal heat, decomposition in that part might have proceeded faster than in other parts. The fact that the lower beds were more anthracitic than the upper beds pointed to an influence acting from beneath and

not from above.t

**Papers on Iron and Steel,' London, 1840. + Memoirs of the Geol. Survey, vol. i., pp. 217 to 221, 1846.

64 The Coals Of South Wales.

In 1859 Dr. J. P. Bevan* described the distribution of anthracitic and bituminous coals, and attributed the anthracitisation to " trap-rocks far below the surface, which have never appeared." The alteration was believed by him to have been ettected before the "Upper Measure Coals" were deposited,

Mr, Thomas Joseph,+ in 1870, classified the coals according to their behaviour when burning, and showed on a map the distribution of the various classes in the eastern part of the coal-field. The gradual progress of the change from east to west was clearly recognised, but, in addition, certain faults were credited with throwing in a higher stage of anthracitisation. Mr. Joseph noted also "the regular gradation of change upwards from the lowest to the highest seams." He concluded that the coals had originally been bituminous or " dark-smoky,' and-had been subsequently altered, the measure for the change being marked by the progressive development of " slip cleavage " in the coal-seams. The change was attributed to magnetic or galvano-magnetic action, and was considered to have been long posterior to "the occurrence of faults."

In 1877 Mr. E. T. Hardman? attributed the anthracitisation to internal heat, caused by intrusion of plutonic rocks. Prof. Galloway,§ in 1884, classed the coals as " long-flaming dry coal above; the caking coals in the middle; and the dry steam, or anthracitic, coals at the bottom." The loss of bituminous matter was attributed to the seams having been covered by a greater thickness of strata, and consequently exposed to a higher temperature in the anthracitic region than elsewhere,

In 1900 Mr. C. A. Seyler published the results of a large number of analyses and discussed in great detail the classification of coals, but did not touch upon the causes of anthracitisation. Tn 1908 Mr. John Roberts**, in evidence given before the Royal Commission on Coal Supplies, described the distribution of bituminous, semi-bituminous, and anthracitic coals in South Wales, and estimated the area occupied by each class. Mr. David Burns}+ discusses various objections to the theories in which anthracite is Supposed to have resulted from the loss of volatile matter in a bituminous coul, and comments on the fact that in going from coking coal to anthracite there is a diminution of ash. He suggests that chlorine disengaged by volcanic

The Geologist, vol, ll, p. 75, 1859, t Trans. S. Wales Inst. Eng., vol. vii, p. 137, 1872. t Journ. Roy. Geol. Soe. Lreland, New Series, vol. iv, p. 200, 1877.

, y Trans. brine Nat. Soe., vol. xvi, p. 20, 1885 ; and 'Course of cetures on Mining. Pub. by the §. Wales Inst. Eng., Cardiff, 1900, Proe, S. Wales Znst. Hngq., vol. XXl, Pp. 483 1898-1900, and vol. XXH, Pp, 112. See also Analyses of British Coals and Coke,' Introduction,

1907, Guardian, 1907, and ' Practical Coal Mining,' vol. i, p. 67, London,

oa at Com. on Coal Supplies, 2nd Rep., 1904, p. 302, and Plates 21,

tt Trans. WV. of England Inst. ME, vol, liv, 1904, Appendix 40.1.

—— ae

Origin Of Anthracite. 65

action combined with the hydrogen of the bituminous coal, while oh of the hydrogen combined with the oxygen of the coal to orm water. The free hydrochloric acid thus formed carried with it some portion of the ash as chlorides. This hypothesis is not well supported by evidence.

There was thus a general agreement that the anthracitic character had resulted from a change effected upon coals which had been originally bituminous. Three explanations of the change had been put forward, namely, that the anthracitic seams had been more deeply buried and consequently exposed to a higher temperature, that they had been altered by the neighbourhood of plutonic rocks, and lastly, that they were more affected by slip-cleavage.

To all of these theories serious objections present themselves, In the part of the coal-field where the measures are thickest, and where the seams were most deeply buried in Carboniferous times, the coals are bituminous. The same remark applies also to the covering of Secondary rocks which was subsequently spread over them. That covering was thickest in the southern and bituminous region where part of it still survives, and thinnest, if indeed it extended at all, over the northern and anthracitic part.

The trap-rocks of Pembrokeshire, which were ete to as showing the probability of similar molten masses aving penetrated under parts of the coal-field, are of pre-Carboniferous age, and therefore can have had no effect upon the Coal Measures. Moreover, coals, where whin-sills have come into contact. with them in other coal-fields, have been coked and not anthracitised, while at the same time the percentage of ash has largely increased. 8

Slip-cleavage is not developed in anthracitic seams, nor does the theory that anthracitisation is due to the escape of volatile matter accord with the fact that the lower seams are generally the more anthracitic. ;

The hypothesis that the anthracitisation was due to disturbance of the strata was put aside in consideration of the facts mentioned by De la Beche, and in view also of the distribution of anthracite in Ireland and elsewhere. a

In taking the view that the differences between the anthracitic and bituminous coals of South Wales are mainly due to original differences in composition we are guided by the following considerations :—

1. While the charts confirm the general conclusions which have long been held on the distribution of the various classes of coal, they show further that some seams, or some groups of seams, possess a certain individuality. In some there are local anthracitic areas of which no evidence appears in others; the rate also at which the change to anthracite takes place differs in different seams. From a combination of these causes the rule that every seam is more anthracitic than the one above it 1s by no means universally true. Again, not only do certain stains differ from those above and below them, but bands in the same

66 THE COALS OF SOUrH WALES.

seam may show considerable differences in composition. These characters lend no support to a theory of the seams having been altered by one common cause acting subsequently to their deposition, such, for example, as regional metamorphism.

2. The iso-anthracitic lines show no definite connection with the faults and disturbances. The dislocations of the strata in South Wales fall into three systems :—

(a) The nearly east and-west disturbances which traverse Somerset, Devon, and the south of Ireland, involving within their northern margin the Vale of Glamorgan, Gower, and South Pembrokeshire.

(4) The west-south-west system which runs for the most part north of the coal-field, but branches of which traverse the Vale of Neath, the valley of the Tawe and part of the anthracitic region.

(c) The faults which range across the coal-field with directions ranging from south to south-south-east,

Of these three systems the east-and-west (a) and the westsouth-west (b) are similiar in their characters. Both attect broad belts of country, and are accompanied by sharp folding and overthrusting, yet one of them (a) traverses part of the coal-field where the seams are bituminous, though they may be vertical or even inverted, and sharply folded, as in Gower. That the other (b) traverses the anthracitic region appears therefore to be an accidental coincidence, though the fact that the most easterly appearance of a west-south-west disturbance in the Vale of

eath agrees in position with the on-coming of the anthracitic character, was at first sight strongly suggestive of a connection between the two.

The north-and-south faults (c) have a local effect upon the quality of the coal. The nature of the alteration is not brought out in any of the analyses quoted in this volume, the object. of which is to show the ied quality of the coal, but is reported to consist in the loss of bituminous matter, The fact, however, that the iso-anthracitic lines ran approximately at right angles to the faults sufticiently disproves any connection between the two. Moreover, the north-and-south faults are neither so large hor sO numerous in the anthracitiec parts as in some of the bituminous parts of the coal-field.

The north-and-south faults sometimes throw into opposition coals of different degrees of anthracitisation. The vertical displacement effected by these faults often amounts to 200 yards, and in exceptional cases to 800 yards. The seams now brought face to face were, therefore, originally separated by a thickness of strata equal to the throw of the fault, and differ in accordance with the general rule that the lower seams are the more anthracitic. No example has come to light of the same seam permanently changing in degree of anthracitisation on the opposite sides of a fault. It is to be inferred from these facts that the anthracitisation was prior to the faulting,

3. The anthracitisation jis obviously not connected with the

existing outlines of the coal-field, as determined by denudation, The anthracitic region appears to have lain principally outside

os

Origin Of Anthracite. 67

the north-western margin of the main coal-field and to the west of it, in Pembrokeshire. Most of it has been removed by denudation, but so far as the surviving part of it enables us to judge it must have extended in a direction slightly south of west. The form of the iso-anthracitic lines suggest that it never extended eastwards beyond Monmouthshire, if so far; its westward limit is, of course, unknown. Again, there is no connection between anthracitisation and depth from the present surface. Slight changes in the quality of the coals are observable at their outcrops, but it has not been proved that these changes are in the direction of anthracitisation. On the other hand, in the bituminous region the coals continues to be bituminous so far down as they have been followed, while in the anthracitic region the coals are anthracitic up to their outcrops.

It appears, therefore, that the coals had assumed their present character before either the outlines or the surface-configuration of the coal-field had been determined by denudation.

4. A feature in the anthracites which is brought out by the collation of analyses consists in their freedom from ash as compared with the bituminous coals. The fact is important from the point of view of the origin of anthracite, for obviously the alteration of a bituminous coal into an anthracite by the loss of bituminous matter from any cause would increase the percentage of ash.

The comparative freedom of anthracite from ash has Jong been known, and has been alluded to by several writers. The fact is brought out by Mushet's analyses,* and is commented on by Richardson.+ Mushet's analyses are proximate only, and . therefore do not yield data for the C/H ratio. On classifying them according to the fuel-ratio, we find that the average percentage of ash ranges from 3°43 in 96 analyses of bituminous coals, to 3°66 in 56 analyses of semi-bituminous, 2°61 in 25 analyses of semi-anthracite, and 2°50 in 16 analyses of anthracite. That fuel-ratio is not the best basis of classification has already been shown (p. 50), but it suffices to distinguish roughly the four classes named. Melly? gives as one of the distinctive featuresof anthracite a low percentage of sulphur and ash. Mr. David Burns also calls special attention to the small proportion of ash in anthracite§

By ash is meant all the incombustible residue. This includes not only any slaty films which are too thin to be picked out from the coal, but all pyrites, sulphates, and carbonates which line cracks in the coal, or are disseminated through the coal, as well as the inorganic material contained in the tissues of the plants which formed the coal. In the analyses quoted on pages 14-16 no attempt has been made to discriminate between these different sources of ash, and it is questionable whether much

'Papers on Iron and Steel,' by David Mushet. London, 1840.

+ Proc. Inst. C.E., vol. viii, 1849, p. 98.

t Trans. N. of England Inst. M.E., vol. xxx, 1882, p. 175.

§ Trans. N. of England Inst. M.E., vol. liv, 1904, Appendix 4, p. 1.

68 The Coals Of South Wales.

would be gained by doing so. The minerals which line cracks in the coal are as likely as not to have been derived from the coal itself, and, at any rate, to separate them out before analysis would give a wrong idea of the coal as it is put on the raps be The sulphur, moreover, could never be completely eliminated, as was shewn by Percy in 1875+. The presence of alumina in the ash would seem at first sight to prove that the ash was partly of sedimentary origin. But it has been shown to be "a Rinicibletts and abundant constituent of the ash of many, if not of all, the species of terrestrial Lycopodia; . . . that it is present in notable quantity in at least one species of treefern though practically absent in others; and that it occurs in insignificant amount ... in almost every plant in which its presence has been carefully sought for.'* "For these reasons we will take the analyses in their original forms in considering the distribution of ash, remarking merely that the great differences of ash in some of the coals, and especially in those of the bituminous part of the coal-field, may be partly due to other causes than difference in the original composition of the coals themselves. Our conclusions must be formed on averages rather than on individual samples.

For the purposes of this inquiry we can use only those seams or groups of seams which can be traced through both the bituminous and the anthracitic areas. Of these the most prominent is the Ras-las and its supposed equivalents. The seams below the Ras-las persist as a group, though they are not traceable individually. The following diagrams (Plate 9) show the result of plotting a curve to represent the percentage of ash in the Ras-las and underlying seams, the analyses being arranged in the order of the carbon-hydrogen ratio. The anthracites occupy about the left half of the table, the right half showine the steam- and house-coals. In the third diagram the curve has been partly smoothed by taking the mean of all analyses which fall between two adjoining units in the carbon-hydrogen ratio, Thus the mean in the column 25-24 is obtained by combining analyses Nos. 31, 25, 191, 161,52. On the other hand, in each of the columns 24, 23 and 22, 21, only one analysis was available, The violent zigzags in this part of the line may be due therefore, to the approximation to the truth being' less close than where the mean could be taken of a number of analyses The same remarks apply to the column 15-14.

Kxcept for these see de proved parts, the line of means in diagram 3 forms a fairly steady gradient from about 1 per cent. of ash at the anthracitie end, to about 4 per cent. or more at the bituminous end of the scale. A larger number of analyses would probably still further smooth the gradient, but even as it stands it proves the general rule that ash diminishes with anthracitisation. In connection with this may be taken the fact that the anthracitic coals are more often " solid" than the

t+' Metallurgy,' p. 568. A. H. Church, Proe. Roy. Soe., vol. xliv, 1€83, p. 127,

Origin Of Anthracite. 69

bituminous seams. Figures for an exact comparison are not easy to obtain, but probably the comparison of a large number of average sections of seams in the two ends of the coal-field would show that the bituminous coals are more apt to be split up by partings of sedimentary material than the anthracitie. Freedom from partings and, to the eye, an almost perfect homogeneity are familiar characters in anthracitic seams. The seams themselves also are probably on the average rather thinner.

Tn order to ascertain what percentage of ash is contained in a mass of miscellaneous plants, and what is the nature of the alteration effected by spontaneous heat, two samples of meadow hay from the same rick were obtained through the kindness of Messrs. Dumbelton, the one coming from near the outside. where comparatively little heating had gone on, the other from the centre of the rick, where the hay had been much heated and had become almost black. As the difference in moisture in the two samples was considerable, both were dried at 105° ©. before analysis. The analyses were carried out exactly as for a coal, and the results obtained were :—

Provimate Analysis.

Light (outside) Dark (heated) sample. sample, Volatile matter - "pt 76°69 69°41 Fixed carbonaceous residue Bayer 0) 2 lesiI} Ash: - - - - - - - 761 9°28

Ultimate Analysis.

Carbon - - - - - - A528 46°82 Hydrogen - - - - - - 5°85 5°33 Oxygen - - - - - zt 39°18 36°75 Nitrogen - - - . - - 2713 1°82 Ash - - 761 9°28

or calculated on "ash-free " sample :—

Proximate Analysis,

Volatile matter - SF eee - 83°00 "6°51 Fixed carbonaceous residue : - 17°00 23°49

Ultumate Analysis.

Carbon - - - - - - 48°96 51°61 Hydrogen - - - - - - 6°33 5°88 Oxyeen 0 E'S 42°41 40°50

Nitrogen - - - - 2°30 201

It will be noted that the percentage of ash in the light (outside) sample is 7°61 and in the dark (heated) sample 9-28. Presumably the greater part of this ash was contained in the

70 THE COALS OF SOUTH WALEs.

plants. Further, the net result of the alteration by heating was to diminish the percentage of hydrogen, oxygen, and nitrogen, and thereby increase the percentage of carbon and ash.

The foregoing statements may be summed up as follows :—

The seams are not all similarly anthracitic, and though each seam is generally more anthracitic than the one above it, there are many exceptions

to this rule. ; 2. The anthracitic character was not due to faults, but existed before the

faults were formed. 3. The anthracite existed as such before the coal-field was reduced by

denudation to its present dimensions. ; ; 4. The percentage of ash diminishes par passu with the decrease of

bituminous matter.

These conclusions point to the variations in the composition of the coals having been either original or at least of very early date. For the disturbances of the strata and the denudation which brought the coal-field to its present shape, were both in the main accomplished before Triassic times. The differences between the coals therefore already existed before any of the Secondary rocks were laid down. Further than this the evidence derived from the distribution of anthracite does not carry us, but the remaining arguments point to the date of anthracitisa. tion having been contemporaneous with the deposition of the Coal Measures—the strongest being that which is derived from the variation in the percentage of ash, for it is obvious that the variation cannot be due to su sequent alteration.

A' further argument may be derived from the existence of pebbles or fragments of coal in some of the conglomeratic bands which occur not infrequently in the Penpant Grit of South Wales and in other coal-fields, As pointed out by M. Renault,* these coal-fragments are enclosed in bands of sandstone or argillaceous sandstone. They sometimes have the fracture of ordinary coal, with alternate bright and dull layers, and are angular ; or again, some have been rounded into true pebbles. They have not been deformed by the pressure of the sandstone which envelops them, nor have they shrunk since they were enveloped. It is to be inferred, therefore, that they were derived from some pre-existing coal-seam, and had already acquired their hardness and definite volume when they were buried in the sand—that is to say, they had passed into the condition of coal while the Coal Measures were still in process of nspem a

n seeking to account for an original difference in the composition of coals, it seemed worth while to inquire whether there was any connection between it and the distribution of the Coal Measures before they were curtailed by denudation. No part of the original margin of the Coal Measures has survived, except possibly in parts of Pembrokeshire, but there is sufficient evidence to enable us to sketch its position approximately,

The evidence commences in the Lower Carboniferous rocks.

quelques Micro-organisms des Combustibles Fossiles,' Bull, de la Soe. ce UIndustrie Minérale, sér. 3, t. xii, 1899, and t, xiv, 1900. Also separately published.

Si ee al

Origin Of Antiiracite. 71

The limestone-series is well developed in South Pembrokeshire, but dwindles away rapidly and is actually overlapped by Millstone Grit towards the north. Throughout the main coal-field the northward attenuation is no less marked, as is proved not only by a comparison of the relative thicknesses on the north and south crops, bat by the poor development in the outlier of Pen Cerig-catch. Lastly, at the north-east corner of the coal-field the whole limestone-series does not exceed 100 feet in thickness, as nS with about 500 feet further south. Traced in an east-and-west direction the thicknesses are relatively more constant, with a general tendency, however, towards expansion in the south-westerly region of the coal-field.

Assuming that the northward attenuation continued in the tract from which the Carboniferous rocks have been denuded, the original margin of these rocks must have lain not far away from, and appears to have run approximately parallel to, the present margin of the coal-field.

The position of the original Soe of the Coal Measures is more problematical, for by analogy with other regions they may be assumed to have overlapped the Lower Carboniferous rocks, and to have extended still farther north. Moreover, their margin probably occupied positions successively farther north as the subsidence which led to the deposition of so huge a mass of sediment progressed. The reasoning, however, which has been applied in the case of the underlying rocks gives a somewhat similar result.

The varying thicknesses of the Lower Coal Series, which alone of the subdivisions of the Coal Measures has a sutticiently wide distribution for our present purpose, is shown in Plate 9. The Lower Coal Series extends from the No. 2 Rhondda Seam (or its equivalents) down to the Farewell Rock or ae of the Millstone Grit. Most of the measurements are taken from shaft-sections published in Vert. Sects. of the Geological Survey, Sheets 80, 81, 83, 84, and 85. But few, if any, of the shafts have reached the Farewell Rock, and several have not been carried down to the lowest coals; in such cases an addition has been made for the estimated thickness of the unproved strata.

The smallest development is found at the east end of the coalfield, where the Lower Coal Series is 625 feet thick. The maximum increase takes place thence in a direction rather north of west, a thickness of 1,710 feet and 1,747 feet being reached in a distance of 12 miles. In the next 4 or 5 miles, however, there is a considerable drop, for in the Rhondda valleys the thickness averages about 1,430 feet. West of these valleys expansion sets in again and continues to the end of the coal-field.

The expansion, however, is more rapid along the South Crop than along the North Crop, so that a considerable difference between the two sides of the coal-field develops westward. The greater thickness of the measures of the South Crop is partly illustrated in Plate 2, in which Sections 3,4, and 7 represent the North Crop, while Sections 2,5, and 6 represent the South Crop. The direction of maximum thickening is somewhat west of south

72 The Coals Of South Wales.

in the western part of the coal-field as compared with somewhat north of west in the eastern part.

Assuming as before that attenuation marks an approach to an original shore-line, this map suggests that the original margin of the Coal Measures also may have been roughly parallel to the present margin of the coal-field, but that it curved southwards at the eastern end. There appears to have been an area of least subsidence somewhere to the east of the coal-field, possibly in the neighbourhood of the post-Carboniferous anticline which brings up Silurian rocks in the Usk inlier.

A comparison of this map with the charts showing the isoanthracitic lines lends no support to the suggestion that the distribution of anthracite had any connection with the osition of the shore-line, Itis true that in the western end of the coal. field the anthracitic character increases as the thickness of measures (decreases, and again in the eastern end the group of seams illustrated on Plate 5 loses bituminous matter towards the region were the measures are thinnest. But, on the other hand, itis obvious that the anthracitic area is far trom coinciding with the region of smallest thickness. On the contrary, the smallest thickness in the south-east and the greatest thickness in the south-west are both associated with bituminous coals.

Moreover, it is not the case in other parts of the kingdom that anthracite is associated with marginal deposits, South Staffordshire and the Forest of Wyre being notable examples. It appears, therefore, that though the anthracitic region of South Wales may have been nearer the original margin than much of the bituminous region, that circumstance does not account for the difference in the coals,

Though we can offer no explanation of the distribution of the anthracite, we may point out that coals are known to vary in character both according to the kind of vegetable remains, and according to the parts of the plants of which they are formed. That, again, the preservation of the vegetable mass varied according to the local circumstances, such as the distance it was drifted, the depth of water in which it was submerged, the length of time that elapsed before it was buried, and the nature of the sediment. which covered it.t Not only do neighbouring veins show variations due to one or other of these causes, but even parts of the same vein may differ considerably. As an extreme case, the band of cannel which is associated with the No, 2 Rhondda Seam may be mentioned.*

t On these points reference should be made to the exhaustive researches on the origin of coal contained in the following works :—Grand Eur F.O., 'Flore Carbonifére du Département de Ja Loire et du Centre de A France,' Paris, 1877, Fayol, H., and others, ' Etudes sur le terrain houiller du Commentry,' Soe. de U Industrie minérale, St. Etienne, 1887-93. Renault, B. 'Sur quelques Micro-organisms des Combustible Fossiles,' 0), 1899-1900, and separately published. Barrois, ©, 'Le Mode de Formation de la Houille," Ann. Noe. Géol. du Nord, t. XXXiii., 1904. De Lapparent, A., 'Traité de Géologie,' Ed. 5, 1906, pp. 976-990. Potonié Vale ane antatehung Bay Ricinkohle, Berlin, Ea. 4, 1907, ;

Country around Pontypridd and Maestég' (Aj yur epee y YI nd Maestég' (Jem, Geol. Sur vey),

ee

a te

Origin Of Anthracite. 13

It is a fact, moreover, that most coals consist of lamin: of different appearance, the two kinds most commonly distinguished being dull coal and bright coal. Though it has not been shown, so far as we are aware, that any bituminous coal contains lamin: of true anthracite, it is certain that the dull and bright coal differ in the amount of bituminous matter they contain, the dull coal being described as "mineral charcoal."* The dull coal, moreover, can frequently be seen to be formed of fragmentary flattened stems, while the bright coal seldom shows organic structure. In all these variations between seams, and between parts or laminze of the same seam, we see differences that can only be due to original deposition.

While, however, giving due weight to the evidence that the anthracitic character of the coals in part of South Wales is due to original conditions of deposition, we do not lose sight of the changes to which coals are liable in the process of time. It is a gerreral rule that, other things being equal, coals associated with older formations approximate more closely to the anthracitic condition than those of later date. The rule is subject to many exceptions, for local circumstances, such as intrusion of igneous material, regional metamorpbism, dislocation of strata, and the thickness and nature of the superimposed material, all produce some effect. The older the formation the greater is the chance of it having undergone one or other of these vicissitudes, while, apart from this, the lapse of time alone tends to effect changes in the character. So far as regards South Wales, it might be argued that the general rule that the older seams are the more anthracitic is due in part to one of these causes, namely, the fact that they were more deeply buried and exposed

See analyses given in 'Coal, its History and Uses,' by Professors Green, Miall, Thorpe, Ricker, and Marshall. 8vo., London, 1878. To prove this point in a Welsh coal, a block of Three Quarter Coal from Monmouthshire was split along some dull layers, which presented a characteristic appearance. The dull material was scraped off and readily reduced to a powder not unlike charcoal. Another portion consisting wholly of bright coal was taken from the same block. The dull powder and the bright portion were then analysed with the following result :—

Proximate analysis of two samples of coal from the same block of the Three Quarter Vein.

; Dull charcoal- Bright Coal. like Powder.

Moisture - - E 2 2 75 1°68 Volatile matter - - - 31°63 14:71 Fixed carbonaceous residue 63°96 arene Ash 5 é - 2°66 6°44

Fuel-Ratio - - - 2°02 524

74 The Coals Of South Wales.

to a higher temperature than the newer seams.* There is, however, no evidence that the coals in the synclines in South Wales are more anthracitic than those in the anticlines, though the difference in level sometimes amounts to several thousand feet. It would apparently be easy to over-estimate the effect due to this cause. Of all the suggested causes of alteration subsequent to deposition, none appear to have been adequate to produce more than a slight modification of the differences due

to original composition.

The same rule holds good in the coal-field of the Pas de Calais, where it is known as the Loi de Wilt. There it is attributed to metamorphism subsequent to deposition,

Tae ee

man INDEX. 75

Index.

Aberaman, 16, 18. beravan, 4, 5.

Abercarn, 14, 20.

Abercraf, 14, 16, 24,

Aberdare, 14,18; Series, 4, 57—61.

eli M.S, ot.

Alteration of coal, 64, 73, 74; by whin-sill, 32.

Alumina in ash of plants, 68.

Ammanford, 26.

Analyses, methods of, 6—12 ;accuracy of, 28—37,

Anthracite, distribution of, 1, 2 ; effect of storing on, 34, 36 ; later appearance of in newer seams, 2; 43—47, 57, 58, 59, 63 ; defined, 49, 50, 51, 58, 54; carbon-hydrogen factor of, 53—55 ; origin of, 63—74.

Ash, determination of, 7, 29—31 ; diminution of in anthracite, 64, 67—70 ; in meadow-hay, 69.

Atkinson, Messrs. M. W. and J., 8.

Attix, Messrs. J.C.and R. K. Meade,7.

Barrois, Dr. C., 72.

Barrow, Mr. J., 3.

Bay, M. L., 31.

Bedwas Vein, 60 ; analysis of, 18,

Bevan, Dr. J. P., 64.

Big Vein (of Monmouthshire), 39, 41, 4446, 57, 58; analyses of, 14, 20.

Big Vein (Swansea Vale and Cwmamman), 4, 40, 43—47, 56, 57 ; analyses of, 14, 16, 22, 24,

Big Vein (Carmarthenshire), 44, 46 ; analyses of, 22, 24.

Binea Vein, analysis of, 20.

Birchgrove, 20.

Bischoff, Prof. G., 36.

Bituminous coal, defined, 1, 49—51, 54, 55.

Bituminous matter, decrease of in older seams, 2, 43—47, 57, 59, 60, 65, 70 ; decrease north-westwards, 1, 2, 55—62.

Black Vein (Monmouthshire), 39, 46, 56, 57 ; analyses of, 14, 16, 24, 43.

Blaencaegurwen, 24. ,

Blaen Rhondda, 18, 20.

Blaenserchan, 16.

Blaina, 14, 16, 18, 57.

Bodwr (or Bodor) Vein, 46, 60 ; analysis of, 20.

Bonville's Court Colliery, 24, 26.

Box Big Vein, 5, 61; analysis of, 24,

Bramwell, Mr. H., 3.

Branfill, Mr. C. A., 22—24,

Brass Vein, 40, 45, 55, 56 3 analyses of, 16.

" Bright Coal," analysis Oe By

Brithdir Vein, 59 ; analysis of, 24,

Bronbil, 16, 59.

Brynddwey Vein, analysis of, 20.

Brynhenllys, 22.

Bunning, Mr. T. W., 33.

Burns, Mr. D., 64, 67,

Bute Pit, 14.

Cadoxton Vein, analysis of, 20

Cae David Vein, 45 ; analyses of, 22,

Cae Pontbren, 24.

Caerbryn, 24.

Caking power, determination of, 11,

Cannel, 51, 72.

Carbonaceous genus defined, 49, 53,

Carbon, estimation of, 9.

Carbonates in coal, 31, 32, 37.

Carbon-hydrogen ratio, 13—24, 52,

Carboniferous Limestone overlapped, 71.

Carway Big Vein, 56; analysis of, 24,

Cawdor, 22, 58.

Celynen Colliery, 24.

Charcoal Vein, 43, 60 ; analysis of, 20.

Church, Prof. A. H., 68.

Classification of coals, 1, 48—54, 64.

Clyndu Vein, analysis of, 18.

Clyne Valley Colliery, 24, 26.

Clynhebog Vein, analysis of, 22.

Coal-pebbles, 70.

Coking by whin-sills, 65.

Collection, methods of, 3.

Colliery Guardian Co., 2, 13—27.

Combustion, method of, 9—11.

Composition of different parts of seams compared, 38, 42. ;

Corrie Vein, 46, 59, 60; analysis OL) 16.

Cribbwr Vein, 45, 55, 56; analyses of, 14) iG.

Curly Vein, 46, 60; analysis of, 20.

Cwm Bran, 5.

Cwm Clic, 16, 20, 59, 60.

Cwm Gors, 22.

De la Beche, Sir H. T,, 2, 13—27, 63, EF

76 Index.

De Lapparent, M. A., 72. roms,

Denudation, subsequent to anthracitisation, 66, 67, 70.

Depth from surface not a cause of anthracite, 67, 74.

Deterioration of coal, 33 —37.

Dillwyn Colliery, 20, 22, 58.

Disturbances of strata, 63, 65, 66.

Dowlais, 14, 18, 56, 58.

Drap Vein, 46, 57, 59 ; analysis of,

Duffryn Vein (see Dyftryn.)

Dulais Valiey, 58.

Dumbelton, Meiers! 69,

Dunraven, 18, 20, 22.

Dyffryn Vein (Aberdare), analysis of, 18, 43 ; (Llynfi Valley), analysis of, 22, 45.

Ebbw Vale, 18, 58.

Kighteen Foot Vein, 46, 58, 59 ; analysis of, 24.

Elled Vein, 44, 57, 58.

Ell Vein, analysis of, 18.

Emlyn Colliery, 24,

Evens, Mr. 'l., 3.

Faults, effect of on anthracitisation, 66, 70.

Fayol, M. H., 72.

Fermentation, effect of, 63.

Ferrous mineral, effect of on analysis, 30, 31, 37.

Ffaldau, 18.

Fiery Vein, 61 ; analysis of, 20.

Fischer, Prot bees.

Five Foot Vein, 45, 61, 62 ; analyses of, 18, 22, 24.

'Fixed — carbonaceous estimation of, 7, 52. Fick, Prof.' H., 33; 36. Forest Vein, 46, 60 ; analysis of, 24,

Forster Brown, Mr. T., 3.

Four Foot Vein (Aberdare Series), 43 ; analyses of, 18.

Four Foot Vein (Gower), 39, 44, 55, 56 ; analyses of, 14, 16, 26.

Four Foot Vein (Morfa), 45, 55; analysis of 16.

Four Foot Vein (Swansea), 5, 47, GO ; analyses of 18, 24,

our Foot Vein (Ystradgynlais) 24, 43, 47, 58 ; analysis of, 16.

Fuel-ratio, 13—24, 50, 52.

residue,'

Gadley Four Foot Vein, 43 ; analysis of, 18,

Galloway, Prof. W., 64.

Garnant, 12, 24,

Geikie, Sir A., 3.

Geinitz, Prof. H. B., 33.

Gilfach, 22. .

Glan Mwrweg Colliery, 24,

ilyneastle Colliery, 18.

Glyn Colliery, 24."

Glyn Corwg, 16, 60.

Glyn Neath, 14, 58.

'Gower, 60, 66.

Graigola Merthyr Colliery, 18.

Graigola Vein, 5, 40, 46, 47, 60, 61; analyses of, 18, 20. f

Graig Vein, 43, 44, 60; analysis of, 20.

Grand'Eury, M. F. C., 72.

Graphite, 50, 51.

Gras-uchaf Vein, analysis of, 22.

Green, Prof. A. H., 73

Green Vein, 46, 57, 59 ; analyses of, 22, 24.

'Gross Coal Index,' 51.

Grout, Prof. F. F., 48, 51.

Gwauncaegurwen, 22.

Gwaunclawdd, 14, 16.

Gwendraeth-fawr, 1.

Hardman, Mr. E. T., 64.

Hart, Mr. F., 34.

Hartig, Prof. E., 33.

Hedley's Vein, analysis of, 20.

Hill Pit, 24. '

Hill's Plymouth Merthyr Colliery, 18, 58.

Hirwain, 14, 56.

Hood, Mr. A., 3.

Hook, 24, 57.

Horn Vein, analysis of, 14.

Hughes Vein, 46, 60, 61 ; analysis of,

Hydrogen, estimation of, 9, 29, 33.

Hydrous minerals, effect of in analysis, 33, 37.

'Inert volatile, 50, 52.

International Colliery, 24.

"Intrinsic value' of coal, 51.

Treland, anthracite in, 65.

Iso-anthracitic charts, explanation of, 55—62.

John, C. v., 33.

Jones Price, Mr. T., 3. Jordan, Mr. H. K., 3, 5. Joseph, Mr. T., 64.

Kilgetty Vein, analysis of, 24.

Leland, 1.

Lignitious coal, 49—51.

Little (Brass) Vein, 40 ; analyses of, 16, 26.

Llanelly, 1, 5, 20.

Llangyfelach, 18.

Llanhilleth, 14.

Llanmorlais, 16.

Llantwit No. 3 Vein, 5.

Llynfi, 14, 22, 26, 56.

'Loi de Hilt,' 74.

Loughor Fiery Vein, analysis of,

Cacti

Ao

at i.

a

a

:

INDEX. nie

Lower Coal Series, thicknesses of, ba715.79: a Four Foot Vein, analysis of,

es Level Vein, 55 ; analyses of,

4, 26.

Lower Pumpquart Vein, 46, 55, 56; analysis of, 22.

Lower Trichwart Vein, 46, 55, 56 ; analysis of, 22.

Lower Vein, 44, 55, 56; analysis of,

Lower (Welsh) Vein, 59 ; analysis of,

Lunge, Prof. G., 9. ynch Vein, analysis of, 24.

Machen, 16.

Maesteg, 58.

Marginal deposits, 70, 72.

Marshall, Prof., 73.

Martin, Mr. H. W., 3.

Meade, Messrs. R. K., and J. C. Attix, 7.

Meadow-hay, analysis of, 69.

Meadow Vein, 45, 55, 56; analysis

hots 16.

Melly, Mr. E. F., 67.

Meta-bituminous coal, 49, 54.

Meta-lignitious coal, 54.

'Metamorphic theories of anthracite, 63—67, 73, 74.

Miall, Prof. L. C., 73.

Middle Vein, 44, 55, 56 ; analyses of, 14, 22.

'Mineral charcoal,' analysis of, 73.

Moisture, estimation of, 6, 7;

effect in analysis, 28, 29 ; effect on stored coal, 34.

'Morfa, 14, 16, 56, 59.

RVG a erot Hee 29,

Mushet, Mr. D., 63, 67.

Mynydd Black Vein, analysis of, 16.

Mynyddislwyn Vein, 5, 60 ; analyses

of, 18, 24 ; after storing, 35, 36. Mynydd Newydd, 18, 20.

Nantyglo, 16, 18.

Neath, 20,

en Cross Hands Vein, analysis of, 22.

Nine Foot Vein (Aberdare Series), 4, 43, 45, 56, 57, 59; analyses of, 14 ; after storing, 35.

Nine Foot Vein (Morfa), 45.

Nine Foot Vein (Ystradgynlais), 46 ; analysis after storing, 34.

Nitrogen, estimation of, 8, 9.

Old Castle Colliery, 20, 61.

Old Coal, 43, 44, 55, 56 ; analysis of,

Onllwyn Colliery, 24.

Ortho-anthracite, 53.

Ortho-bituminous coal, 49, 54. Ortho-lignitious coal, 54. Oxygen, estimation of, 30, 31.

Para-bituminous coal, 49, 54.

Park and Blaina Colliery, 16.

Parr, Prof. 8. W., 48, 50.

Pas de Calais, 74.

Peacock Vein, 40, 43, 44, 47, 553 analyses of, 16, 22, 24.

Peat, 50, 51.

Pebbles of coal, 70.

Pembrokeshire, 1, 2, 56, 67, 70, 71.

Penlan Vein, analysis of, 16.

Penrhiw, 20, 24, 60.

Pen-y-filia Vein, 45 ; analysis of, 18.

Pony graig Vein, 59, 60; analysis. of, 16

Per-bituminous coal, 49, 53, 54.

Percy, Dr. J., 2, 13—27, 33, 36, 68.

Playfair, Dr. Lyon, 2, 13—27.

Pontardulais, 61.

Pontyberem, 14, 22.

Pontyberem No. 1 Vein, analysis of,.

Pontypool, 5.

Potonié, Prof. H., 72.

Primrose Colliery, 16, 18.

Proximate analysis, 7; defects of, 28, 29.

Pseudo-anthracite, 49, 53.

Pseudo-bituminous coal, 54.

Pumpquart Vein, analysis of, 24.

Pwllfaron, 14, 16, 24.

Pyrites, effect of in analysis, 30—32, 37; on spontaneous combustion, 33, 34.

Ras-las Vein, 39, 40, 48, 44, 56, 57, 59, 68; analysis of, 14; after storing, 35.

Red Ash Vein, 59 ; analysis of, 24.

Red Vein (Monmouthshire), 43, 57 ;. analysis of, 20.

Red Vein (Ystradgynlais), 41, 45, 46, 58, 59, 60 ; analyses of, 20, 22.

Renault, M. B., 50, 70, 72.

Reynalton Colliery, 26.

Rhondda No. 3 Vein, 46, 60 ; analysis of, 20.

Rhondda No. 2 Vein, 2, 4, 40, 44, 59, 60, 73 ; analysis of, 16.

Richardson, Mr. J., 67.

Richters, Prof. E., 33, 36.

' Ring coal,' 1.

Roberts, Mr. J., 3,.64. ;

Rock-fawr Vein, 40, 59 ; analysis of,

Rock Vein (Pontypool) (see Ras-las Vein). Rock Vein (Machen), analysis of, 16. Rotten Vein, 46, 60 ; analysis of, 20. Riicker, Prot. A. W., 73.

Sampling of coal, 6.

Semi-anthracite, 50, 51, 53.

Semi-bituminous coal, 49—51, 53, 55.

Sequence of seams, 4.

Seyler, Mr. C. A., 2,11, 13—27, 4g— 50, 52, 64.

Six Foot Vein (Aberdare Series), 45, 57, 58 ; analyses of, 18, 22.

Six Foot (Graigola) Vein, 5, 40, 45, 47, 60, 61 ; analyses of, 18, 20.

Six Foot Vein (Llanmorlais), analysis of, 16.

Slatog Vein, 46, 60 ; analysis of, 20.

'Slip-cleavage,' 64, 65.

South Staffordshire com ared, 72.

South Wales Institute of engineers,3.

Specific gravity, estimation of, 6,

, 12.

Spontaneous combustion, 33. Stanllyd Vein, 4, 44, 56, analyses of, 14, 16,24. - Steam coal, 4; analysis after storing,

Bis

Stewart, Mr. W., 3.

'Stone-coal,' 1.

Sub-bituminous coal, 49.

Sulpbur in coal ; estimation of, 8 ; effect of in analysis, 30, 31, 32, 68.

Swansea Five Foot Vein, 45, 47, 61, 62 ; analyses of, 18, 22, 24.

Swansea Four Foot Vein, 5, 47, 60; analysis of, 18, 24.

Swansea Six Foot Vein (see Six Foot or Graigola Vein).

Swansea Three Foot Vein, 45, 61 ; analysis of, 20. wansea Vale, 61.

Tallis, Mr. Fox, 3.

Temperature, effect of, 63, 64.

Whisknédeos of measures, 5, 71, 72.

Thorpe, Prof. T. E., 73.

Three Quarter Rock Vein, analysis of, 18.

Three Quarter Vein, 40, 43—46, 57; analyses of, 18, 24.

Three Foot Vein (Clyne Valley), 55, 56 ; analysis of, 24.

Three Foot Vein (Swansea) (see under Swansea).

Index.

Tillery Vein, 4, 59; analysis of, 24.

Timber Vein, 55—57; analysis of, 24. :

Tirpentwys, 14, 20, 24.

Trap-rocks, 64, 65. .

Tregloin (Trigloin) Vein, 41, 55, 56 ; analysis of, 20.

Two-foot-nine Vein, 43, 44, 57, 58; analysis of, 18.

Ty-chwyth, 22.

Ultimate analysis, 9, 29—37.

Upper Four Foot Vein, 44, 57, 58, 61 ; analysis of, 18. '

Upper (or Pen-y-graig) Vein, 60; analysis of, 16.

Vale of Neath, 57—59 ; Disturbance,

Variations in seams, 39—42.

Varteg, 14, 18.

Ventilation of coal, 34.

Vobster, 63.

Volatile matter, estimation of, ay A affected by moisture, 28.

Ward's Fiery Vein, 47, 61; analysis of, 20.

Weig-fawr, 20.

Welsh Vein, 59 ; analysis of, 20.

Shee ers Vein, 5, 46, 60 ; analysis of, 16.

Whin-sill, effect of on coal, 32.

Wight, Mr. W. D., 3.

Wood, 50, 51.

Wyre Forest, 72.

Yankee Vein, 44, 55; analysis of,

Yard Vein (Clyne Valley), 44; analysis of, 24.

Yard Vein (Aberaman), analysis of,

Yard Vein (Llynfi), 45 : analysis of,

Ynyscedwyn, 14, 22. Ynysfaio, 18. Ynysygeinon, 22. Ynysymond, 20. Ystradgynlais, 16, 24.

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