The geology and ore deposits of Hedley mining district, British Columbia [microform]

Camsell, Charles · 1910 · Historical

"IR,—I beg to submit the following memoir on the geology, and ore deposits of Hedley Mining District, with an appendix on the adjacent districts of Henry

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

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Canada Department Of Mines

Geological Survey Branch

Hon. W. TemPLeman, Minister; A. P. low, Depvry MInister; R. W. Brock, Director.

MEMOIR No, 2 GEOLOGY, AND ORE DEPOSITS

Hedley Mining District

British Columbia

By

Charles Camsell

Teme. .

Ottawa Government Printing Bureau

Mo. 109%

ee) ees ee eT

41\ 1] Ules Ll

Canada Department Of Mines Geological Survey Branch

Hon. W. Temriemyy, Misistex; A, Pp, Low, Deputy Mixtsrer ; R. W. Brock, Dinecror,

MEMOIR No, 2

Thr: Geology, And Ore Deposits

Of

Hedley Mining District

Britisit Columbia

Ky

Charles Camsell

9185—]

Letter Of Trans\ Ittal.

ro R. W. Brock, Ese, Director Geological Survey, Department of M nes,

"IR,—I beg to submit the following memoir on the geology, and ore deposits of Hedley Mining District, with an appendix on the adjacent districts of Henry creek and Golden Zone,

I have the honour to be, sir,

Your obedient servant,

(Signed) Crarnes CAMSELL.

June, 1909,

9185—i4

Contents.

Introduction— General Statement... .. .. .. .. ., Reh Selgin eee Peaihn'a Csteu eee enigma TT Field work and acknowledgments; 5. feo. ee Cony urs mane 2 Situation and means of COMMUINGAtION nats versa ee ee +7 oes oko History of developmentiais. ss os .0 gfe 4 Rt Oe acces Cceine. 001s: Previous work and LUCENE es Be By ne van pee seilee wae ee apnes, 28 Bibliography... ., PPE CMe NRIse eee et hed AP Lee Meena, oe ae. PAO

Summary and Conclusions General Geology.. .. .. .. SiS siesits 8 Keio ates canta e ouae eee SiRrerey oe Wiaightee oak OD ORerdenositan aera aan ee COMETS S LUE eer ran Aen

General Character of the District—

RopogrAnhy dee meinen ee Si fncds bol Rea Ath 9 tea st oA Pecos esos ake taz ee aO

General account.. .. .. UEMECSO ce oti: oko ae ats encase one AOL Regionaliawseccee on wee Side SPIELE MENGE yioie Cie Siete site Peretti Ale OG Lotalitn cates Sele CU SSG HG. On PA et rd shy a ee tee,

Detailed account.. .. ., TEMES ONO OF oes cid GK eee tag OT: Drainage.. .. .. .. Satin Bh ciate seer Heasielietee meme eae COT Crrades= Scythe oe SOM me met uk rien iturin cing ecriya ee REO eves ee So hsin t's Se Alea reouined mene, oc, USB

Climate and agriculture.. Sei alert stb nceusyeim Antu tay Reh ee Aa eevee: ee BR

General Geology—

General statement... .. .. .. GUN RO NOE ARCS MAS CG. eS eOih ors Goenees C4 MUGwiCnialsnwya erie see ee aieai al wal Misiae.ineiteg ad. gels. SE LQG aliost ake e vow es suete ane AS RMR ee Nesp Wiehehu ee Otel el Ge

Table of formations.. .. .. ., COP Oia 405) (SONGS AGENT RCO Eee gaen

Summary description of formations—

Cache Creek group.. .. .. .. GORGES SO RODE Pa eae creta ich cee ake Redtop formation... .. .. . KERR Sy CEs: cee beta ee. en 4S Nickel Plate formaiion,, .. Ls SR echo salen os ane tate eigh rem ee, © Ui Red Mountain formation.. .. ORO ica tee oon eriianhaet~ Meer fe Aberdeen formation.. .. ., .. Sb peitis evs vibe ray SSA NY Pe ate a Generalized tabular section.. .. .. SUES ue tag Seu aad ieee el ee Columnar seetion.. .. .. .. ., Me Beem e Iomeead eye win fried ORT

Agheousrockss ales oe. Sess Leite enw alt Me cleo aaercuy eats heel OAR

Quaternary deposits... .. .. 0... 0... Bad Fd) Paro aie Wale Meret ae Se ee AD.

Detailed description of formations.. .. .. .. .. .. Peo Reece talk oi ee Redtop formation.. .. .. ., SH Dta et ote Gis gis cies tier ude eel

Dratributions; sac. oO RS ikea a asinine nie 140 SEHIGKMERR oe gen ean Gem CeeRGas hy Ce Ooerscas erherrverese male! Lithology.. pee REX RAL Dar cain Ae Artery Sar eM

or

6 Geological Survey, Canada

General Geology—Continued.

Nickel Plate formation.. SPE ODO iaihtaci LOO Oper se yee one Distribution.. .. .. .. .. sir Ge Eh (ee ae aly ghee ieties te otek Thickness.. .. .. .. .. POROUS rio errmerin rw mrrvereres dt Lithology.. .. ., ., efecto, CMC (a mar Hoe Moreen ee. AL

Red Mountain fortiation...):. 0... wees bs) Wales cee, once. VET Distribution.. .. ., EINE EA! TU LOR C CMCC INCH Fit usr oe yey ot} Thickness.. .. .. .. ., C8) Oe eM witive lee) wal ee tos cailiel ena A OD Lithology.. .. .. .. .. OAD Leah eel ean Nas aie aer Nie BETS Oe 2

Aberdeen formation., OR SOTE SNOW U S ireciOy Eero nan Reece Distribution.. .. .. ., Eee GOA CRs Sorgen pce pk eee Thickness., .. .. ,, SUES MERLE tne nats iach romney eet Ree. tive Lithology.. .. .. 2... eraeqNtane neat ee

Correlation and age of the Cache Creek PROUD Fic cay sate ee ee Diorite-gabbro COMplOx usa eta aeet eee Sema, rere

General statement.. Chea Ret i te crane Dat Wee,

Distribution.. .. .. .. MMB BI ASIF Mesiet Roti nrtsale ean sic Haeuce vale,

Lithological characters. .

Macroscopic.. ., Microseopic.. .. ., ., rae Metamorphism.. ., .. TOSS eh Gir) Riess; Teie. lara es eratetvaiey fares eae

Structural relations.. .. PRG A Eee COL Ay. ode sees peru 7 Interngl.2 205. SUSE Rees al) ee else earn, cares Rely ere Ponce ee PS Certhalesn ease CO SOC MO SEDO ite A cactet Fly he 75

Mode of origin.. .. .. SSEn a) Let tba belah Gneinaits te siolon Grea iedi eee cess CDP

Age and correlation.. ., ., GEICO DAEs Be. sto Am crits tee eee fs

Granodiorite:, ..).. ..).. PAID OE AI Mie Sd eat or ae ICY!

Distribution.. .. .. ., .. OR COAG ACCA Gn. vine eee Bev kei gil

Hithologyes ase oe ge UGS OCOD ACU emtann ral Soom ce TN Macroscopic.. .. .. .. .. Pe ICM pa COED ERR Scena uth amere art: Microscopic.. .. .. ., ECE CARI ED ISOM neta Syn ee, Metamorphism.. .. .. ., PRs Re cence. Pad ile gata tee yet, MSO

Structural relations.. Satie nis Che luasol Foil te earareite etic ep ee EGS Unternalease essere oo qcaBitisiavecercersur'yi8) eit lnsclrhny Test iem bets) Ree ee Oe LORACS TAT oe. oS cote voy ee NG Geeta cen rct Mainans. ici vee tur, es. TIT:

Mode of origin., .. PEAMS BIDIOG BS OE BGO we ee ue Shh ERS:

Age and correlation.. POURS Slelsrt we Ts (on seheH is(irnce, eacntalnes fie teviis O neem a TOL

Dike rocks.. .. .. ESOS fe Fes AN o Jnah ieee oleae sla Nake snyearreel poet Ae, ATOR

Lai.prophyre,. .. .. a POS EO aE Ss ric eaipae ears ery ai Lil

Keratophyre.. .. ., SPOR ETERS OSR seats. feey genie tea) ths rhs whom DAE OG

Aplite and rhyolite.. .. .. ROPER RE NESD OO GU GS ac. Gh Otte nue ee, ONhila

Andesite.. .. ., is I SRS tae cs SiaceLeal se Noa stnierel es Gel teed ele er een OO

Surface deposits... .. ., BOURNE ES SE SOO SSS whet Soe sorte creas he ee ART Glacial deposits.. .. .. TRUDI ALEC ore ey aie SMeAT ENT" Stream deposits.. .. ., PIO eI TI OG Wg Cy Can eee ARE Nea Gy

Structural Beolopye. oo re ater arsnsinty tle) angst sevenestival tt are cigmneorat cL tO

Ute) G fay aye SE ie PETE ick isand ecrt meet weds eee Bi Sine Lie,

BAUS 5 oo. aso Oe Soho Chew tle Bae BO NAO Gat tobe Mr ere, een hie Character and distribution... ., .. Bib Ce Ee Gore Sa Te

OW -3 -3 +3 43 by

iQ -' oot 4

Topographic OXPEGSSION sacs saek eae ta oe 2S) SF) ena orve a DES \ge and cause of EOL GUN rie ge ene 26a ee ee aig aaa SEE

CONTENTS ae

General Geology—Continued. BiSAnYeS i. aise on S$ AW Feehieinn Ge se 7a oe SEA TH 4et wees, PTAe ARE ELY Veen Me ban ee Ke CLM ANS a THAI La Gani AMC Ree ygied hh: Geologic history sec ere ee ee EEE eey cob waar cer eeisargae een MEER Introductory SALOMON c5 ge Nahe ene ws $6, tage 208 Cache Creek sedimentation... .. .. .. .. .. .. Bory ert weed 00 Intrusion and geformationsamoe sec ee eat rhe a by Glaciation and development of present topography... .. .. .. 124 Summary of geologic history.. .. .. .. .. ee sees ww san Loe

Economie Geology—

General character of ore DeDOwite yas acneae eet ee 130 Distribution.. .. .. .. .. Oi TICES RR Aree Crtertrs tr parce Peseete to Mineralogy.. .. .. .. Bren ee hestirensemsersines esis Pert ss teet cin tas List of minerals.. .. .. Misi Seb ener restael sere sh ere cianaeuianee ALAS Goldie vee see avEDMaro7 (OeUN sal is! cop Lae ecm aie ruieeiny anol IG SUV GT es wie en SED Ss io ean aatevas ete crete Deiter reee ALE Platinum... 5. 40+. CUMa Are pre REEto TT wicks nee Gaby? INIGKGL: cte3i Peed Opie yep teed se carers nnn iy F) Cohaltis ie. 2 ete PROG a eeNoe rare: elem we eae) "ar eo oe TSR etradymitess 4. 2000 sit, iScw Atlas Catal Sate eae e's) seein come 198

Pyrite.. uae Arsenopyrite.. .. .. HONS US CREA Gay ee I ree Molybdenite.. .. 6... 0... Sh ORRIN een bys erer ronan weet Galena ven. s oy Ae i cP ea neon sicilemetad Cane taecnscse ace tam TAL Chalcopyriters .. CEM Ifinecerrg Bon Geena ae nil Sphaleritescs 25, 0. on Sot slsonsien ay Patsy cs eecate trees ce esoe. foe, MLET Pynrhotitests ne ne EN EY ra ORE Is) Sein OE Pe eeti ded 1 UU te Sriseaererer te orem MUU A SI ROR Serine. are wane eee ULES Tin onite: My 6y.2 0 cere STs ou ws vente EA ios, oweinea hee AGL Magnetite,aecre a ee he EOE es (Gy toc ern aE Anny yh Oe aye Caloitesciy assy sae see oe ROC OMCH ac a SENT Ary errr 3 PELGANI CGS uhin tac ntiece eee Op Cy Seta Se rey Gen ye rae kn 114 Dleldenariemes pee eee EDEL Orne s Ri verge cry Moen eee 1,1 PYTOXENES oe faci So Ween ee Nei Cele oes ated slau atennscey easreeivew ents CLES Wiotlnstoni tamara are PO IGRCE UG CURE ES tis ext mawen, OLN: Amphiboles.) cron s sheen cate ok SSlie tie aiusielveeuvele. se cat ce eh aan eae Garnct.=; on. eee 1S Ci Cha hee Ns Ger tare al ei he wee dE 7 DIA Gte enna omereee ee SePce Ml surgeon ien Arietta eset atone dae AINIEGS oe meee ee Salhelv.otvd Sia} fersble, te dhe) oura seve tate LAR ADOtitOcceis et ae He tel 60E 1 e. cage rnalee gee or 1a Binythrateees sue, (seas Tai ieier ie: dustentete tom? Gy eter ee ota O NADICICG ani eelee ie eee CON Oca eae On aa nee WEL Gillorites wn caves ee i Wa They cela chic Ges ea eer ya em ve 4S Character of deposits and relation to country rocks— EUR BOSC es YOR eee et Manette tee amtie Pateet Ore and gangue minerals and their paragenesis,. .. .. ., cs, O00 Dinensigns 0s a eee Dantes, create aie VEsis Aste wis Ween se de ie oT ed Boundaries. s0usest ooo. ate A GEG Ch ees oie an MA Pereistenceryctn ae wt me PEI eMC aes tment (Sri Antyy saw ee BGS: Relation to bedding... .. .. .. .. SUedaastuiiia nie Masta he wc ee oats pL ee

8 Geological Survey, Canada

Economic Geology—Continued,

Character of deposits and relation to country rocks—Continued. Relation to fissures.. .. .. ,. REPE STS aNeey er cae w ence Megan recy SEED Distribution of FRINGES ntti Speke carr ancae an Relation to igneous rocks.. .. ., .. totals Fee EUS eter aaret tie ce, LOE Relation to sedimentary rocks.. .. ., SUAS HET Sve ce pea te TOS

Genesis—

Evidence., .. .. ., op fg PDC MC Oana ryan, Ree giro eee Theoretical considerations.. .. .. ., ., SMa eaTARN. sik eis Oe 1

Conclusions and classification... .. ., Sle COSC IC CRD A eter amen A

Age of the ore deposits. . wen eteevaeiyrs 1

Mining, milling, and metallurgy... .. 0.0... SUR Cuts PCC errs seas 1:71

General status and future possibilities... , oa) 48) sigh ner ae tae eee SIRE

Description of mines and properties.. ., ,, SK Gurr oriewes S11 Nickel Plate mine.. PS BESS ODE UST CIO ens eee TT

Hocation se oe a Wiese eee ease tse hh Stvouhvin- comb OO GeGlogy. 3; os ee. Ae EOS OR. EAS Oe ESca ate pil gislete nat Character of the Gepostte. cg, SW sre lene semnventsrye ee AUT General development... RARER WE SS een hie kaa Veh rites on TO Sunnyside mine,, oe Rea Gata eee tetsu Karey tc cere oc eet aa 398 Location.. .. ., ,, PP Scent ty NEUTRAN wees eects cron Teel Caita ine Uae AGS Geology cece ac TO a. PD RAD SACI Sn Dee IES OGMcn omens oy aE Character of the depositsyco ow ati ear buat sce eens ga Om General development., BES ESTOS! Cts Mey arin dan, wh eereeda [. Production.. .. .. HE OSS EPs eas omnivores heen STS Kingston SRN SD ees are eet pe tired oe A EN OSS teris eee ek le: POcatione.. 0, sere SO CAS IDOE Cetp OG Snes eye Yee BT Geology. ves.) Fearn get hah aso Monmnautene at ee OG Character of the u DOSE ee ota en ree: Wai Sees Sines ea se OOD General development.. .. .. SNS Os i waeors sletivege sees tok, (OU Florence BEOUD scicosinste tan Serena 4) SOS a meat eie, ce garda gu ee OOO Humming Bird UPS Se Scat caar ie ory pre era oe ee SO ee TPE: Appendix— i

Golden Zone TE) RECN SEC) te ee yee MEAS Sistemas. -eraqua sees OI Loca traz s,s Sp ates MOC LASSER Carnac roy ty Sy acre Bee 204 Gedo lary n tee RPO Conc Merri Ar Pome eel 204 Character of the deposit.. .. PEGE OG 3G Ct et Be nota ae Pie General development... ., eg eae Eee Or cern eet ys

Henry Creek district... 40 © ee ie eI Os me CTT eOCAtiOn anne ee Er Reha Wie ear omnes tag Sheed 7 oe BOF Geology... eS ER ED OCI. Creare hye gy le so os 207 Character of the depogitvsm see a SOLES BOSE aoe tt hile e BGO; General development., Be Sie SAA Sacie US ey sees cx a etn ee ee 208

Illustrations,

Photographs,

Plate T. Hedley and the valley of Twentymile creek,, -- Frontispiece, in II. Similkameen valley looking west toward Princeton., ,. 34 - ITT. Similkameen valley below Hedley... ,, Si? Sree elie tee eae es IV. Talus slopes on Twentymile CPE cee sorte is Serr 603

CONTENTS Jv

Page. Plate V. Open southern slope of Lookout mountain.. .. .. .. .. 40 a VI. Banding in the Redtop formation.. .. .. .. .. 32 f VII. Cliffs fornied by rocks of the Nickel Plate formation. 56 VIIL. Alternating beds of Limestone and Quartzite in the Nickel Plate formation.. .. ,, Te rita ets oe. st IX. Massive beds of the Red Mountain formation., ., . 64 " X. Banding in the Aberdeen FORMANON gina eaten Oe aS XI. Banding of the Sedimentary rocks due to injected sheets of Diorite POPPY EN. Severin oe Se 80 oh XII. Talus of Granodiorite DIGGS ae acuy il ile ee ae ae 98 s XIII. Exposed section of streain deposits on 'Twentymile ORCO i sreccairaces susan oe oe me a) oe eee oe aa ARO us XIV. The Bradshaw Fault line in Twentymile creek and Bradshaw caiion.. .. .. .. ., weuew tse Sen eimes oe LES ae XV. The effect of Glaciation on the shape of the Similka- Meenev alleyecs rte cu Ne chy ae eee Sees, ieee carn? CARD ve XVI. Polished surface of ore from Sunnyside mine, No. 3.. 152 XVII. Polished surface of typical Nickel Plate ore.. .. .. 154 "XVIII. Banded structure in polished surface of Nickel Plate ore... GON SS cium ornate tice Ore yer Ue oe XIX. Gravity trum-line, lower section., anes st WAL este aot MESO ee XX. Stamp mill and Cyanide plant of the Daly Reduction

Gompanyc atte Aree ee ee eherera Pre

Drawings,

'igure 1, Generalized Columnar section of the rocks of the Hedley GREG acre ne se oe ee Sito: Met MIG Cer eer aT $7 # 2. Natural section across the base of Nickel Plate mountain. 101 ss 3. Section along No. 3 Tunnel, Nickel Plate BING) cevainn ee ena s 4. Diamond drill sections, showing distribution of values.. 168 2 5. East to west section through top of Nickel Plate mountain 168 se 6. Plan of Yale Mining Company's mines.. .. 2. 2... eth iee LOE i 7. Section along No. 4 Tunnel, Nickel Plate mine.. .. oe 28

8. Geological structure sections along the lines A—A and B—B of the Hedley Ltt) SSE COMCOMI. CPeI yA te Me ay

Maps,

No. 1096. Geological map of Hedley Mining distric*., Crred Waal aee) vee, COG "1095. Topographical map of Hedley Mining distriet.. .. eck "1106. Geological map of Henry Creekcdistrictym, in es "1105. Geological map of Golden Zone Mining camp..

The

Geology, And Ore Deposits

Hedley Mining District, British Columbia

By

Charles Camsell. Chapter I.

Introduction. General Statement,

The Hedley district js one which has proved to be of considerable interest to students of economic geology, on account of the unique character of the ore deposits, which apparently have no known parallel in North America; but to Canadians this scientific interest is supplemented by the importance of the region as a produce" of gold. The object of the survey, herewith reported on, was to make a detailed geological study of the whole area, and to investigate the nature, occurrence, and probable extent of the ore bodies, so that some assistance might be rendered to future operators in the district, in the discovery aad working of new ore bodies. The purely geological results have proved to be very interesting and satisfactory, and it is believed that something of interest has been added to the literature of economie geology. The object of the present report is to present in as complete a manner as possible, both the stratigraphical and economic results that have been obtained by this study. From the limited number and variety of ore deposits being developed, and the consequent necessity of drawing conclusions from only a

few of suc. deposits, the chapter on economic geology is not as

13 Geological Survey, Canada

complete as it may be made at some time in the future, but it will Le found to contain Virtually all that is known of these deposits at the present time, and it is believed that much of the information contained herein will be found of some usefulness to prospectors and operators in the district. It is the opinion of the author that all the ore bodies that can be worked to a profit have not yet been discovered in this district, and it is only to be expected that when others become known, variations will be found in the nature and occurrence of these, which may necessitate some modification of the views and conclusions here expressed,

FIELD WORK AND ACKNOWLEDGMENTs.

The following report on Hedley is based on field work carried out in two successive seasons—in 1907, from May to September, and in 1908, from June to the end of August. The topographie harvey of the camp was begun in May, 1907, and carried on thre ughcut that season, mainly by Messrs, <A. O. Hayes and J. A. Allan, under the writer's Supervision. In 1908, about one-third of the map remained unfinished, and this work was undertaken and completed by Mr. Leopuld Reinecke, assisted by Mr. S. A. Woolzey,

Though the area covered by the map is not great, being only about 16 square miles, the time consumed in the topographic work was much longer than might seem adequate for a map of such size, This is accounted for by the physical conditions encountered in surveying, the ruggedness of the ground, and the inaccessibility of some of its parts.

The camp lies largely in the deep and narrow cafion of Twenty. mile creek, where it enters the Sunilkameen river. This caiion is from 2,500 to 4,000 feet deep, and its sides slope downward at angles of about 40°, These sides are gashed by many deep and narrow box canons, so that it was impossible to get into many parts of the area, and others were reached only at considerable risk,

An accurately measured base line, 2,600 feet in length, was laid out in the valley of the river, and a triangulation from this formed the main control for the sheet. Transit and stadia traverses were run between triangulation points, and over all the wagon roads, tramways, and main trails. ° between these traverse lines the detail was put in entirely by work with the plane-table and stadia, or by sketching and triangulation with the plane-

HEDLEY MINING DISTRICT: ORE DEPOsITS Li)

table. All elevations are referred to mean sea-level, and were taken from a bench mark of the Canadian Pacifie railway at the mouth of Twentymile ereek, Mr, Q. I. Cartwright, divisional engineer tor that Company, kindly put ail available data with regard to eleva tions at our disposal, and the necessayy corrections were made.

In the geological work, able assistance was rendered by Mr. J. A. Allan, now assistant to Prof, T. A. Jaggar the Massachusetts Institute of Technology. The historical succession of the rocks, and th: relation of these to the ore bodies, was studied and roughly marked out in the field season of 1907, and samples collected for petrographic study. This left, for the summer of 1908, the delineation of the geological boundaries on the map, and the completion of such other details relating to contact metamorphism ard the ore bodies as were not worked out in 1907.

By August 20, the field work of ifedley was virtually completed, and the remaining portion of the field season was devoted to the examination of certain groups of claims adjoining the Hedley camp, with a view to determining what similarity, if any, there might be hetween ore bodies in different portions of the same district, It wa found that, while in places the geological conditions were somewhat similar, yet as a rule the conditions under which ore hodies were found to occur were totally dissimilar—that is to say, tne Hedley ores are to be considered as being unique, the area throughout Which they occur is a restricted one, and they have no known counterpart in districts outside this area.

Development of the mineral claims of Camp Hedley has not yet reached an advanced stage, a).:! indeed, serious mining operations have been carried on upon onky two of these claims, the greatest depth reached being not more than 250 feet. It is not unreasonable to expect that with the further prospecting and development of other claims in the camp, new ore bodies will be discovered, and in the opinion of the writer, it would indeed be surprising if, as some suppose, the above-mentioned two claims contain all the ore of any economic importance in the whole camp Under these circumstances, and with the probability of further development and discoveries, it would be presumptuous on the part of the writer to assume that this report contains the final word on the geology and ore deposits of the camp; and it is quite possible that when, in the future, a more detailed study is made of these rocks, and particularly of the ore

14 Geological Survey, Canada

hodies, these conclisions may be moditied, or other cone, usiong arrived at, Nevertheless, the present report is presented, witn the belief that in its main features it is Correct, and will require no change, and that any changes that are found necessary at any future time, will ouly be of minor importance, and wil] hot atfeet the value of the report as a whole,

While the geology of the camp is, in meny respects, rather eomplicated, the rocks themselves are, as a rt.., well exposed, and onls on the eastern portion of the sheet are they covered with much drift. Contacts between different types of rock were generally found by a little search, and this simplified to a great extent the working out of geologiea] relations,

With regard to the ore bodies, it was unfortunate that so little work was being done on the great majority of the claims, as it was impossible, without the aid of the owners, to discover places where cuts had been made, or shafts sunk. To this is due, in a great measure, the lack of mention in this report of any Ciaims outside of those owned by two companies and three or four individuals, Every effort, howe ver was made bv the people of Hedley to assist us in carrying out the work. The Yale Mining Co., and the Daly Reduction (, . through their officers, gave us unstinted support, ond saved the party a great deal of time and hard work. The almost daiiy use of the gravity tram-line to ascend the 4,000 feet to the Nickel Plate mine, often when it Was not convenient to curry passengers, was a very great convenience; free access to all the Sunnyside and Nickel] Plate mine workings was accorded at all times, and it is Principally from a study of the occurrence of the ore bodies en these two Properties that deductions are drawn as to the origin and history of the ores of the whole camp.

In almost every case, the owners of claims who lived jn Hedley were willing and eager to lend assistance in examining the ground in which they were interested; but in eases Where owners could not be found, the examination of their claims had to be made alone, and much of interest may have been missed. Altogether, we have to thank the people of Camp Hedley for generous assistance.

In the petrographic study of the rocks and ores, and in the other work incident to the compilation of this report, the writer is pleased to acknowledge the fenerous assistance and advice rendered by all the members of the geological department of the Massachusetts Insti-

Hedley Mining District: Ore Deposits 15

tute of Technology. To Prof, C. EH. Warren, in particu or, ar acknowledgments due for much assistance in the petrograph: study of the different rock species met with, and of the ores; to Poof. R A. Daly, also, for many helpful suggestions in the discussion of magmatic problems,

SITUATION AND MEANS oF COMMUNICATION,

Camp Hedley is to-day the most important mining camp in Che whole Similkameen district of southern British Colu, hia, and ex tains one of the largest gold mines in Conad Osoyoos Mining division, and lies on the S nh iver the mouth of Tw ntymile creek, about 20 rtli International Boundary line, and the same d vest of ¢t 'kanagan valley. In extent the mining locatior am Ver not more than 16 square miles, and aggregate hou Virtually al' of Which are surveyed and Crown

When the first mining claims were locat: im only means of access from the outside world the ney trail, which followed the valley of the Siz wer ning from Hlope, on the Fraser river, throug ta the country. This trail, built in 1860 by Moberly and been used for many years, first by the I[y vs B traders, and later by prospectors, ranchers, an: i t ho thought was ever entertained by any of th of th in the 'mountain at the mouth of Twent ere Nickel Plate mine began to show evidence econ ducer of gold, Wagon-roads were built fron nticto in lake, both to the mine on top of the mountain, and ¢ f Hedley, where the rr ition works are situated. Thi the mine to Penticton is only 28 miles by this road. I inery, equipment, and supplies had to be transpo: ted and much is still brought in this way. From Hedley rtie is 56 miles by the road which follows the Similkameen ley, and until the winter of 1907-8, this was the easiest and most convenient means of entry. The Great Northern Railway Company has recent], completed a branch line inte Keremeos, which is only 20 miles from Hedley, and probably this will soon be extended farther up the river to the latter point. Surveys have been made for the extension of this railway line through the Hope mountains tc the Pacitie

16 Geological Survey, Canada

Coust, so that it will not be long before Hedley will be one of the tations of a transcontinental line. The country on both sides el the Similkameen valley is to a very large extent still unexplored, and is accessible only by means of a few hunting and prospecting

trails, known only to the natives and a few of the older prospectors,

History Of Development,

Unlike the majority of mining camp, or even some others in the Similkameen and adjeining districts, the Listory of Camp Hedley has not been eventful, At no time in the ten or twelve years of its existence bas it beer troubled with a boom; a feature so characteristic of many modern mining camps, and, as a rule, so detrimental to the best interests of the mining industry,

In the years immediately following the discovery of the rich placers of the Cariboo distriet in 1859, great crowds of prospectors and miners from the California gold fields took their way north by Various routes. The principal route followed by these fold seekers was by sea to Victoria, and thence up the Fraser river to the gold fie'ds, An alternative route followed by many was up the Columbia and Okanagan rivers, passing by the mouth of the Similkameen river, and thence overland by Kamloops and the Carihoo trail. Some of the overflow and stragglers, from the latter route, branched off the main route toward the west, and followed the valley of the Similkameen river, prospecting as they went. The travels of this Stream, and some of its tributaries, were fou to carry the metal they were in search of, and pay varying in amov 1 from $4 to #20 5 day per man was struck on the bars and bencl

Placer mining of the gravels in the vicinity of the mouth of Twentymile creek was prosecuted in the early 'sixties, but this class of mining is always of a temporary character; and the exhaustion of the pay gravel is a matter of a very short time, after which the place is desested. This, the first period in the mining history of Hedley, is relatively unimportant. It was of short duration, and is now almost entirely forgotten.

Following the logical sequence, the period of placer mining was only the antecedent of the more important and lasting period of lode mining. This period, beginning from the time that the first mineral claims were staked in the year 1896, has been one of slow but successful industrial development, until to-day the camp ranks

HEDLEY MINING DISTREOT + otee DE POSETs 17

as the most iinportant in the Whole Similkameen district: contains the largest gold mine in all Canada, and gives protnise of still greater development when transportation is improved and mining facilities cheapened,

The first reeord of a mineral elaim in Camp Hedley was in TSE, when C, Allison and J. teardon staked three claims for the Hfon. E, Dewdney and others, on ground that ix now covered by the Climax, Windfall, Winchester, Lookout, and part ot the Nickel Plate mineral claims. Mr. Coulthard also had a claim on what is now the Kingston mineral claim. These four claims were recorded at Granite creek, but they were not considered worth the annual assessment duty and were allowed to lapse,

In 1897, Peter Seott located the Rollo claim, and in the followitu vear, after doing the necessary assessment work on this claim, he located the Princeton, Warhorse, and King. The Mound and Copper Cleft were staked about the same time hy two Swedes, and in August of this year, Wollaston and Arundel located the Horsetly, Sunnyside, Nickel Plate, and Copperfield. Colours could be obtained by panning the red dirt in many of these prospects, and the unoxidized arsenieg} ore was in places exposed, but the owners did not yet thoroughly realize the value of their discoveries, Samples of the surface ore from the Nickel Plate were taken by Wollaston and Arundel to the Provineial Fair at New Westminster and exhibited there. It Was here that Mr. M. K. Rodgers, who is more directly connected with the history and development of the camp than any other person, first saw the ore. He was travelling through the country in the interests of the late Marcus Daly, and Was so impressed by appearance of the ore samples that he immediately started on a trip to the Nickel Plate to make a closer examination and obtain samples, At that time there were no wagon roads in the country, and it took several days of arduous travel by rail, stage, and on horseback, to reach the district from the Pacitie coast. The examination proved satisfactory to Mr. Rodgers, and a bond was taken, in November, on the four claim, Nickel Plate, Bulldog, Sunnyside, and Copperfield, Permanent work on these claims was started in January, 1899, and within a year the bond was taken up by Mr. Rode and the balance of the purchase money paid to Wollaston and Arundel, The claims heeame the property of Mareus Daly, and since then development work has heen continuous.

1s GEOLOGICAL SURVEY, CANADA

For over two years Mr. Rodgers confined all his attention to the preliminary development of the claims, and did not, as so many do, 'ssume that he had a mine before the ground had been thoroughly prospected by tunnels, drifts, and surface cuts. In the meantime, a wagon road had been built from the Nickel Plate to Penticton, and supplies and machinery were brought in by this route.

In October, 1902, the properties having been thoroughly prospected, and proved to be worthy the expenditure of more money, the construction of a tramway to transport the ore from the mine to the valley of the Similkameen river was begun. The erection of a stamp mill and cyanide plant was also commenced, together with a flume 83 miles in length, to bring water for power purposes from Twentymile creek to the mill. These works were completed in May, 1904, and the milling of ore began.

In the meantime, other claims had been taken up, Companies formed, and development work undertaken; but no actual shipments have vet been made, nor has any of the ore been treated by anyone outside the Daly Reduction Company.

The Great Northern railway now being built up the Similkameen valley to Hedley, will probably be the means of renewing interest in the camp, and stimulating claim owners to more thorough prospecting of their claims.

The town of Hedley, named after R. R. Hedley, formerly manager of the Tall Mines smelter at Nelson, B.C., was surveyed and laid out into lots in 1900, The town is built on the dry gravel bed to Twentymile creek, but is protected from floods by a strong embankment built to confine the stream to a restricted channel. Electric light is supplied from the power plant of the Daly Reduction Company, and a system of waterworks has been installed. Including the men emploved in the mines, the population of the town is in the neigh-

bourhood of 250 persons,

PREVIOUS WorK AND LITERATURE,

The literature of previous work in Hedley is neither long nor varied. While the town itself only dates from the vear 1900, the first recorded mention ot the rocks is found in the Report of Proeress of the Geological Survey for 1877-78. by G. M. Dawson. What is now known as the Nickel Plate mountain was referred to then hy

Dawson as the Striped mountain, a name suggested by the distinetly

Hedley Mining District: Ore Deposits Ey

banded appearance of the outcropping edges of the beds exposed, overlooking the Similkameen river. This Striped mountain is the hill on the east side of Twentymile, and not as some suppose thet on the west side. Both are striped and the name might refer to cither. While Dr. Dawson rightly attributes the banded appearance to the alternation of dark and light siliceous and argillaceous bands, this is only in a measure true, for the intrusion between the bedding planes of sheets of igneous rock which Weather to a rusty brown has accentuated this feature, and contributed more to the banded appearance than the mere alternation of dark and light sedimentary beds,

Dawson also mentions the vicinity of Twentymile creek as one of the earliest places at which placer gold was mined in British Columbia.

During the years 1859, 1860, and 1861, the International Boundary commission was engaged in delineating the line ef the 49th parallel, and Mr, Bauerman was connected with this commission as British geologist. [is notes on the geology of the Similkameen river, as well as the rest of the mountain section, were compiled by G. M. Dawson and published asa part of the Geological Survey report for the years 1882-3-4, Bauerman followed the old trail which leads directly past the place where the town of Hedley now stands, and he makes mention of the very striking character of the rocks there exposed.

The Annual Reports of the Minister of Mines for British Columbia, from the year 1898 up to the present, contain references to the Nickel Plate mine and Camp Hedley. The majority of these simply contain a statement of the amount of work dune annually, without any reference to the geology or the mode of oceurrence of the ore bodics. In 1901, however, a visit was paid to the camp by Mr. W. F. Roberts: 5 Provincial Mineralogist, and the annual report for that year is interesting as containing the first official and reliable account of the conditions obtaining here. In the report for the year 19°5, there will also be found a detailed account, by a reliable authority, of the mill and methods used by the Daly Reduction Company in the extraction of the gold from some of the ores of Camp Tledley.

After the discovery of the Nickel Plate mine, and up to the Present time, Hedley has been Visited hy many mining engineers, and some geologists, who were attracted thither by the unique

ISs—24

20 Geological Survey, Canada

character and peculiarities of the ore bodies. Little, however, has been written for publication by any of these men.

Three articles in popular style, by H. F. Evans, were published in the Mining World, of Chicago, but as the examination of the geology and ore deposits by this gentleman was confessedly hurried, some of the statements have not been borne out by our more extended survey.

A paper by R. A. Daly, in Vol. 17 of the Geological Society of America, entitled 'The Okanagan Composite Batholith of the Cascade Mountain System,' contains much interesting information on the history and method of intrusion of the igneous rocks of the 49th parallel. The distance from Hedley is only about 25 miles, and much that Dr. Daly has written has a bearing on the igneous hist. y of the Hedley district,

For a general history of geologie and physiographic events in the Cordillera of British Columbia no better Synopsis can be found than that of G. M. Dawson, given as the presidential address to the Geological Society of America, in the year 1901.

Besides these, which have a more immediate connexion with the geology of the Hedley district, some bulletins and professional papers by Smith, Willis, R issell, and Calkins on the geology of the State of Washington, and published by the United States Geological Survey, contain much that has a bearing on events on the Canadian side of the International Boundary line,

BIBLIOGRAPHY, The following is a list of references which haye been consulted in the preparation of this report. It contains Virtually everything that has been written on this district :— G. M. Dawsoy, Geological Survey of Canada. Report of Progress, 1817-78. Part B, pp. 84 and 156,

G. Gipss. Jour, Am. Geog. Soe. Vol. 4, 1874.

H. BaverMan. Geol. Surv. of Can. Annual Report 1882-3-4, Part B, p. 18.

W. F. Ropertsox. Annual Reports of the Minister of Mines, B.C. 1898-1907,

W. J. Watermax, B. C. Min. Record, November, 1900, p. 44,

W. TW. Weed. Trans. A. T. M. E. Vol. 33, p. 734.

HEDLEY MINING DISTRICT: ORE DEPOSITS yg

IH. F. Evays. Min. World, Chicago. Vol. 25, p. 662. Vol. 27 pp. 885, 1015, 1057,

C. A. Alphonson. Min. World, Chicago, May 30, 1908,

R. A. Daty. Geol. Soe. A-n., Vol. 17, p. 829, 1906.

C. CAMSELL. Summary Rep. Geol. Surv., Can., 1907, p. 24; 1908, De Gi:

Report on the Mining and Metallurgical Industries of Canada, Mines Branch, Dept. of Mines, 1908, pp. 123, 131, and 244.

G. M. Dawson. Geol. Soc. Am., Vol. 12, 1901, p. 59.

3AILEY Wittis. U.S. G.S. Bull. 40, 1887.

I. C. Russerc. U.S. G, S, 20th Annual Report.

Siti and Carkins. U.S. G. 8. 3ulletin 235, 1904,

G. O. Surin and Baitey Wins. U.S. G.S. Prof. paper No. 19,

23 GKOLOGICAL suRvry, CANADA

Chapter Iti.

Summary And Conclusions. General Ghology,

The oldest rocks of the Hedley district are sedimentary pocks, These alj belong to one conformable Series, and have been referred to the Céeche Creek group of Dawson's classification. No determinable fossifs have been found in them, and their correlation with the Cache Creek rocks of the Kamloops map-sheet to the north has heen made purely from lithological evidence. Until further palwontological evidence js obtained, they are called Carboniferous in age.

These rocks comprise a total thickness of at least 6,300 feet. This estimate is a minimum ore, and covers only those rocks found within the limits of the map. Sedimentary rocks lying conformably above these, cover a large area outside the map, to the west, and may repre- Sent a continuous series extending through Carboniferous into Triassic times,

The sedimentary rocks of the district have been divided for convenience into four formations, the division lines of which are taken arbitrarily at some well-defined horizon. The lowest of these js the Redtop formation, consisting of massiye limestone, cut off by intrusive granodiorite at the base, above which is a series of interbanded limestones, quartzites, and siliezous argillites, with some voleanic tufts and breccias. Above this is the Nickel Plate formation, which is made up of sassive limestone beds at the top and bottom, with interbedded impure limestones and quartzites between. Overlving the Nicke] Plate formation is the Red Mountain formation, which is essentially voleanie and consists of andesitie tps and breecias of varying coarseness. The Aberdeen formation lies at the top of the whole series, and is represented by thin bedded limestones, quartzites, argillites, and voleaniec materials,

Sedimentation was terminated by uplift of the whole region, whereby the rocks were elevated into a broad anticline. the crest of which lies over Eighteenmile creek, its axis running north and south. Dips in the centre of thi. arch are low, becoming almost vertical toward the west in the Aberdeen rocks,

Hedley Mining District! Ore Deposits 23>

Immediately following this uplift, or coincident with it, batholithic intrusion of igneous rocks began. Masses of diorite and gabbro were first intruded in the form of stocks, dikes, and sheets, anid highly metamorphosed the older sedimentary rocks, forming at the same time the primary ore deposits. This took place some time during the Mesozoie period and was accompanied and followed by considerable faulting.

During Tertiary times, a second period of batholithie intrusion was instituted by the eruption of granodiorite on an enormous scale. Consequently, when this was finished, the Carboniferous rocks cf the Hedley district were cut off on almost all sides by igneous rocks, and now remain only as a large roof pendant in the batholithie mass. This eruption was accompanied by considerably less contact metamorphism of the sedimentary rocks in the Hedley district than the previous eruptions, and apparently by little mineraiization.

Erosion has sculptured the rock masses of the Hedley district

ince the uplift following the Carboniferous sedimentation, and :e amount of waste has been enormous. Renewed power of erosion was obtained by uplifts both in post-Laramie and in Pliocene times. To the erosion period following the post-Laramie uplift is due the uniformity of level of the upper surfaces of the region, while the cafioning of the deep valleys is attributed to the post-Pliocene erosion period. It has been estimated that the uplift during this last period was at least 2,500 feet.

Although the whole district was covered by ice during the glacial period, the action of this on the upper surface levels is not marked. The erosion here was slight, and the chief evidence of oceupaney by ice is the thin mantle of glacial debris, and the boulder erratics. In the main valley, however, there is much evidence of concentrated action, indicating that the valley was occupied by a glacier long after the upper levels were virtually free, its concentration in the valley being accompanied by greater velocity of movement, resulting in the scouring out of many hundreds of feet of material from the hottom of the Similkameen valley, giving the characteristic U shape now seen.

The final act in the creative history of the district was the deposition of thick deposits of washed gravels in the main valley, by waters overladen with glacial material derived from the vanishing

24 Geological Survey, Canada

glaciers of the Cascade mountains. These again are being destroyed, terraced, or carried away by the action of the streams, ORE DEPOSITS.

Up to the present time, gold has been che only product of the mines of the Hedley district, and only two mines, namely, the Sunnyside and the Nickel Plate, are producing. The ore deposits were first discovered in the year 1596, but in the years immediately: following, their development was slow, on account of the distance from established lines of communication, and the lack of any road better than a mere pack trail. After the entrance of the Yule Mining Company, however, in the year 1899, progress was more rapid, end this Company, after spending a great deal of time and money in demonstrating the value of their properties, building wagon roads and tramways, and opening up the country, detivered the first ton of ore to be treated in the stamp-mill, in the spring of 1904, Since then, operations have been continuous, save in exceptional years when the severity of the winter necessitated the closing down of the mill for a short time. The total tonnage of ore treated since 1904,

up to the close of 1908, was 153,013 tons. From this, over $2,250,000

worth of gold has been obtained, at approximately $15 to the ton. The formation of the primary ores of the district dates back to the intrusion of the gabbro-diorite rocks, This event is the first in the intrusive igneous history of the region, and is referred to a part of the Mesozoic period, some time after the deposition of the Carboniferous sediments. The intrusion of the diorite and gabbro rocks was exceedingly important, and as they were introduced very widel: into the overlying sedimentary rocks in the form of stocks, dikes, and sheets, they exerted a Strong and widespread influence on them. Wherever the gabbro-diorite rocks are in contact with these sedimentary rocks, extensive contact-metamorphism js apparent, resulting in the development of large masses of garnet, epidote, and diopside. The alteration is greatest where the igneous rocks are most abundantly intruded inte the sediments, that is to say, within a radius of 1 mile from Climax bluff, which js about the centre of the contact metamorphic zone. The whole series of sedimentary rocks is more or less affected by these igneous intrusions, but in some the alteration is more extreme than in others. Quartzites, argillites, and voleanic tuffs have suffered relatively little. The massive limestone beds have suffered more, resulting in the erystal-

Hedley Mining Distrie T? Ore Deposits 20

lization of caleite, or more rarely in the metasomatic development of some of the lime silicates, particularly garnet and diopside. The most intense alteration has been in the impure limestone beds of the middle portion of the Nickel Plate formation, where the beds ure not thick, and are interstratitied with some quartzite strata. The result here has been the complete elimination of the carbonates, and a replacement by silicates, so that the rock is now a@ mass of rarnet, epidote, diopside, and quartz, with occasionally some uxinite. This metamorphism appears not only on the main contacts of diorite and gabbro, but also on the dozens of apophyses, laree and small, which have been given off from the stocks. Most of these apophyses outerop on the eastern side of the Nickel Plate mountain, as well as on the south, and are exposed there beeause of the uniform dip of the strata to the westward into the stocks of gabbro and diorite, 'which lie on the western 'ope of the mountain,

Wherever contact meumorphism has been effected in the sedimentary rocks, more or Jess mineralization has accompanied it. Like the contact metamorphism, mineralization has not been marked on the granodiorite contacts. It is much more notable on the diorite contacts, aud greatest of all, on contacts of gabbro. The result of this mineralization has been the formation of arsenopyrite, pyrrhotite, chalcopyrite, pyrite, and sphalerite, and these minerals accompany the lime silicate minerals in such a way that their contactmetamorphic origin appears beyond a doubt. The origin of these ores is believed to be due to the emanations of water and metallic substances originally contained in the igneous magma, bu released from it by a decrease of pressure on its reaching higher levels in the earth's crust. The deposits are, therefore, of contact metamorphie origin, and contemporaneous with the intrusion of the rocks of the gabbro-diorite complex.

The gabbro-diorite complex is made up of two main types of rocks, of which gabbro is the basie type. This rock is also very slightly younger in age. All the known ore bodies of the district are associated with intrusions of the gabbro, and it appears clear that this phase of the complex is genetically connected with the origin of the ores,

The ore deposits are irregular in outline, and with ill-defined "boundaries on all sides but the foot-wall. This foot-wall is generally

the gabbro intrusive sheet that has been responsible for the meta-

26 Geological Survey, Canada

morphism and mineralization, On all other boundaries the values in the ore body gradually fade out into low-grade rock. The strike of the ore bodies on the Sunnyside and Nickel Plate mines is generally about N 70° W, and the dip is rarely more than 30°, and is dependent on the dip of the gabbro intrusive, which forms the footwall, The ore bodies have no apparent connexion with fissures, and ure not always governed by the stratifieation of the se limentary rocka,

From analysis ot the different sulphides occurring in the ore bodies, it was found, that while all have some gold, as well as a little silver, the highest values lie ia the arsenopyrite. 'Vhile all the workable ore bodies must Contain arsenopyrite, and the richest ore bodies carry more arsenopyrite than the poorer, it is certain that much arsenopyrite oceurs throughout the district, that carries little or no gold. When, however, arsenopyrite occurs in the metamor- 'phosed limestones on a gabbro contact, some yulues in gold are always found. The nature of the association of mold w ith the arsenopyrite has not been ascertained. On the surface, much of it was found free, and in quantities visible to the eye, but below the zone of oxidation the association with the arsenopyrite is much more intimate, and little of the gold is seen. It is believed that in the 'lower portions of the ore body the gold occurs either sparingly disseminated jn the cleavage planes of the ursenopyrite, or else it is in actual solid solution in this mineral,

The zone of oxidation in this region is very shallow, never mor than a few feet in depth. Secondary enrichment has, however, #pparently taken place, below the zone of oxidation, by descending meteoric waters. It has been found that in ore bodies having a low angle of dip, there is 4 concentration of values on the foot-wall, The gabbro foot-wall is a dense close-grained rock, and relatively impervious to solutions, but even this is often enriched for a few inches on its upper surface by gold values. In the case of the Nicke] Plate ore body, -which lies on a gabbro foot-wall, and has a pitch of xhout 25° W, an impervious trough has been formed by the conjunetion of the gabbro with a cross-cutting dike of so-called quartz porphyry; and in this trough a concentration of values has taken place at a depth of about 200 feet below the surface.

A careful study of the nature and occurrence of the ores can, in the opinion of the writer, lead to only one conclusion as to genesis. Contact metamorphism by the intrusion of igneous rocks into lime-

IEDLEY MINING pIstTree CP) ORE DFPOSTTs at

stones, during which the primary ores were f rimed, followed

Sitti

secondary enrichment by descending meteorite waters. wall torily explain every cceurrence of workable ore jn the listrict

The association of the ore bodies with the recks of the gabby diovite complex, and particularly with the gabbro phase, is well proven, To this intrusion it is believed the ores are primarily du It is believed that the contact metamorphisin, whereby the calcareous sedimentary rocks were changed to a mass of lime silicate minerals, was due to the heat of the molten magma thrust into them, This metamorphism was aided to a very large extent by the action of water and other materials, which were given off by the molten magma and transferred to the intruded rocks. That there was a transfer of material is shown by the presence of substances—particularly arsenopyrite and axinite—in the contact metamorphie zone, which are not native to the sedimentary rocks, and are not found elsewhere in them. These substances, therefore, could only have been derived from the gabbro magma. Among thes. substances are iron, zine, copper, arsenic, sulphur, boron, and silica. Gold, also, is believed to have been present in the magma, for assays of the gabbro generally reveal traces of gold. The intimate association, also, of gold with arsenopyrite denotes a common origin for both.

This gabbro magma, which gives evidence of having had a eonsiderable amount of superheat, or of containing substances which greatly reduced its viscosity, carrying the above-mentioned substances in solution, forced its way upward through the overlying sedimentary rocks. As it reached the higher levels, the pressure gradually diminished, and the dissolyed substances, including the gold, were released and passed off into the adjoining rocks, there to assist in the work of contact metamorphism, and to do the mineralizing. Those strata of limestone which were more porous and thinbedded, and afforded the easiest and most numerous channels for the emanations, were the most highly altered, and received the greatest addition of material, while quartzites, argillites, and the more compact limestones suffered less. In this way, the primary ore deposits were found at and near the contact the gabbro intrusives.

That the ore deposits in this district a.. more generally associated with the dikes and apophyses of gabbro, rather than with the main stocks, is a phenomenon common to many other contact metamorphic deposits. It is believed that this is to be explained by the supposi-

28 Geological Survey, Canada

tion that the dikes and apophyses are more highhy charged with magmatic waters and volatile substaness than the main stocks,

The depth at whieh the ore forming substances were released from the molten magma must have been considerable, so that the present outcrops were originally deep-seated, and have only been exposed by erosion. The typieal Bangue minerals, garnet, epidote, diopside, and tre molite, are characteristic of the deeper zones, and are not readily formed under conditions of medium or low. presure and temperature, Their presence, therefore, indicates considerable depth of formation, 'The fact, also, that this region ha been subject to erosion ever sinee the uplift of the sedimentary rocks, which must have been in early or middle Mesozoie times, leads to the inference that hundreds, and perhaps thousands of feet of rock which onee overlaid the present surface have been eroded away,

After the formation of the primary ores by the intrusion of the gabbro, there was little, though some, later enrichment from the same Magmatic source, Few fractures or fissures were formed hy the cooling and contraction of the igneous rocks, and of the contact zone, but those that did form became channels for the introduction of some of the enriching sulphides. Subsequent to this, ore deposition from the same source was entirely at an end. Later fractures were formed, but no new i ditions were received through them from a deep-seated source, On the surface, erosion and oxidation advanced deeper and deeper, and concentration of the gold values went on, Not, however, until these ore bodies eame within the zone of in fluence of surface waters, was any change effected in them, Then the fissures, previously formed, permitted a free circulation of water, and the gold, leached out from its associated sulphides near the surface, was carried downward to enrich the ore body blow, In this process concentration of values Was greatest when dams had been

formed by impervious cross-cutting strata.

HEDLEY MINING DISTEetre fr) ORK DrPostrs ze

Chapter Iti.

General Character Of The District. Topography, General Account,

Regional.—Extending northward through the State of Washing: ton, the Caseade Mountain svstem gradually diminishes in height on approaching the International Boundary line. In this latitude it is made up of two distinet branches, which are merged into one large block of mountains to the south in Washington. The western branch, which contains both the Skagit and Tozameen ranges, js the stronger and more persistent one, and continues northward along the eastern side of the Fraser river, until it finally dies out in the Interior Plateau, or is cut of hy the Thompson river when it bends to the east.

The eastern branch of this range continues northward, geross the boundary line, as far as the Similkameen river at Keremeos, Where it is abruptls interrupted by the deep valley of that stream, Northward of the Similkameen river the range is continuous in th same trend as before, but it here goes by the name of the Okanagan mountains, The crest line of these mountains is a gently sloping one to the north, and is characterized by a succession of broad] rounded summits, rising little more than 7.000 feet above sea-level, This range is neither long nor strong, and in the country about the head of Twentymile ereek soon dips down to the rolling eountry of the Interior Plateau, where elevations barely reach 6,0 et shove sea-level, The transition from the Okanagan range to the Interior Plateau is not so abrupt as many observers would have us helieve. When viewed from the west, ata point on the Similkameen river between Hedley and Princeton, the gently sloping crest line is well brought out. The highest points of the Okanagan range at the boundary line are about 8,000 feet. The upper level of the Interior Platean, at the head of Twentymile ereek. is almost 6.909

feet above sea-level. Between these two points. which are 25

eh GhLOLOGICAL SURVEY, CANADA

Hiiles apart, the Okanagan range dips down into the Intersor Plateau, and, omitting 4 valley of the Similkameen river, nowhere in that distance along the range is there any very abrupt change from hountain range to plateau, but there is an even slope throughout This is the more natural way for a mountain range to die out along its longitudinal axis, and the Okanagan range being simply due to a Warping of the surface along a definite line, follows the normal order and dies out by a flattening of the Warped surface,

Drainage from the Okanagan range js principally toward the east and west. On the east, the streams flow either directly into Okanagan Jake, or by way of Keremevs creek into the Similkameen river, On the Western flank are four small but steep-graded streams flowing directly into the Similkameen river. These are Fifteenmile, Sixteenmile, Fighteenmile, and Twentymile creeks, so named by the early travellers from their respective distances above Keremeos, which was then the most important place in the valley. The largest and most important of these streams is Twentymile ereek,

Between the two main forks of the Cascade range—that is to say, the Okanagan mountains on the east, and the Hozameen and Skagit mountains on the west—lies the southern end of the great Interior Plateau revion of southern British Columbia. This, in the latitude

o-r 1

of the He wey srea. op about 49° 95' has a width of about 50 m 'les, quickly increasing, however, to the north, Almost exactly half way between these two ranges, in this latitude, lies the Princeton depression, toward which al] slopes from the east, south, and west converge downward. In this depression the two main streams of the district unite, the Similkameen river flowing in from the south, and the Tulameen river from the west. The united streams then turn eastward and slightly southward toward the Okanagan mountains, flowing on a rather steep down-grade against what is, on the higher surtace level, an up-grade, and cutting a deeper and deeper valley through these mountains until they join the Okanagan river just at the International Boundary line.

Northward of the Similkameen river and the Princeton depression, the Interior Plateau region stretches away for hundreds of miles into the northern part of British Columbia, entirely unbroken by any notable mountain ranges,

HEEPLEY MINING DISTRIOLS ont DEPOstts oe

Local.—The Hedley area lies on the western flank of the Okuna ean range, and only about 6 or 7 miles from its crest line. Its topography is neither that Which is characteristic of a mountain region, nor is it typical of the plateau region as a whole, but unites features which are found in both. Its higher levels are sone what above the average of the plateau region, yet these upper levels simulate in a general way the upper levels of the plateau. The streams, however, cut so deeply into this surface, giving a vertical! relief of about 5,000 feet, that, from the valley bottoms, an imy res: sion of mountain topography is conveyed.

The Similkameen viyer flows through the southwest corner of the Hedley area, and only two of its tributaries are here ineluded, namely, Twentymile ereek, and Eighteenmile creek. All other creeks or gulches in the area are merely tributary to the above mentioned streams.

DETAILED ACCOL NSN Tr.

Drainage.—The general slope of the whole country in and adjacent to the Hedley district is toward the west, that is to say, toward the Princeton depression, and away from the crest line of the Okanagan range. In spite of this, the Similkameen river flows in an exactly opposite diveetion, or toward the east, and cuts directly through the whole Okanagan range. If one follows down the course ot the stream eastward from the basin-like depression at Princeton, it is noticed that the banks of the valley rise higher and higher, and become proportionately steeper, until the axis of the range is passed through; then there is a sharp descent of the uplands, to the valley of the Okanagan river,

There is no reason to believe that the origin of the Okanagan range is different from that of the rest of the Caseade system, and it is very probable that the Separate ranges which make up the Cascade system acted as a unit, and have a like history. The last uplift of the Caseade mountains in Washington is placed by Smith and Willis! at ¢! close of the Pliocene, and though we have no direct evidence bearing on this point in the neighbour-

hood of the Hedley district, there is no reason to Suppose that the 'US.G.S. Prof. paper No. 19, Contributions to the Geology of Wash-

ligton.

Oe GEOLOGICAL SURVI ¥, CANADA

Okanagan range was uplifted at a different period. Accepting this date as reasonably certain, we can draw some conclusions as to the history of the Similkaeioes v: Lat.

It appears clear, . ; the writer's nid, that there must have been a valley existing on i, resent dine f the Similkameen valley, previous to the Upitt Oo! tie Okunagay range, otherwise it is diffeult fo account for the Way in winch the stream now flows castwa'rd through this ranee out of the low-lying Princeton depression, and izainst what is. on the higher levels of the country, a strong uperade, The Soneral level of the Princeton depression is not nore than 3,000 feet above sea-level, while the notches in the Okanagan range are generally somewhat over 6,000 feet. It 1s believed, therefore, that the Similkameen valley existed in its present course previous to the uplift of the Okanagan mange, and that this uplift was of such a slow and gradi al nature that the erosive force of the stream was strong enough te keep pace with it, and never at any time rapid enough te dam back the stream or affect its course. There ix no evidence to prove that the uplift was so rapid as to materials change the course OL pre-existing streams, except, perhaps, those of stat] volume. Tf sneh were the case, the waters of the Similkameen and Tulameen rivers could readily have found an outlet horth from the Prineeton basin into the Nieola River system, for the divides here are very much lower than those of the Okanagan range. It js

coneluded, therefore, that the formation of the Similkameen Valley

aitedates the Pliocene uplift of the Okanagan ranve, and the stream

is consequently an untecedent stream, "avontymnle ds ane f the largest tributaries , P the Similksanne en

river between Princeton and Keremeos, a dj since of 45 miles, Tt

has a total length of only about 15 mil sand heads in a number of

small branches in the plateau region along the Western slope of the

Okanagan ranee. Its volume is neve! VOry great, and on account of the aridity of the climate, it is winost dry jn the late Sum ner,

Twentymile creek furnishes all the Water-power for milling, hand. age, and eleetrie lighting that is used in the distriet, and dy the conservation of its water in a small lake at the head of its east branch, sutlieient js saved to tide over the dry season.

Riehter nmile, ; it 2 miles to the eust of Twentymile creek

is smaller in Volume, and shorter, Like Tweutymile ereek, it flows

into the Simil! ameen river from the south. It rises on the western

Liedley Alining District? Ore Deposits

flank of the Okanagan range, and is only about To miles in length, Its water is used entirely for the irrigation of lands lying in the bottom of the Similkameen valley. These two streams, with the Similkeeneen river, carry all the running water of the district, all the other streams being merely intermittent.

Springs are to be found in half a dozen places in the district, hut the outtow of water is very small, and these also vanish in a dry season. The fall of rain and snow is always very light, averag-

top of Nickel Plate mountain, Much of this water runs off

ing about 11 inches annually at Hedley, and about 22 inches on the Immediately, owing to the high grades, but some is absorbed by the soil and rock, to slowly trickle out in springs durine the remainder of the year. The quantity of underground water is not great, and never of much inconvenience in mining operation In the early spring, owing to melting snows, there is somewhat more than in the late summer; and as the mines are nowhere timbered, some care has to be exercised at that time in the chambers and glory-holes

te avoid falling of blocks that become detached from the walls and

roof by seeping water and the jar of blasts.

(grades,—The erade of the Similkameen river is fairly uniform throughout the portion of its length in and adjoining the Hedley distriet. The difference in elevation of the bed of the stream between Tfedley and Princeton is #40 feet. 'This for a distance of 25 miles vives an average erade of almost 19 feet to the mile. Below Tedley, if there is any variation in this grade, it is not noticeable to the eve,

A characteristic of all the tributaries of the Similkameen river in the me ighbourhood of Hedley is the sudden steepening of their grades, shortly before entering the main valley. This feature was referred to in a previous report,' and was then attribute lL entirely to glacial causes, On the south side of the Similkameen valley, Henry creek, Jameson. Susanne, and Paul creeks all show this characteristie. In the ease of Twentymile ereck, it is not so marked as in the ease of the smaller streams, which have not. the same power of erosion; but even here it js noticeable. In the last ' miles of its course the stream falls at the rate of 150 feet to the mile, and flows through a narrow Veshaped eafion, in places 1.000 feet deep.

Stunmary Report, Geological Survey ef Cay Va, THAT.

ot GEOLOGICAL SURVE Y, CANADA

Fightoe: le creek shows this characteristic much more strongly. In the last one and a half miles of its course before reaching the bottom of the Similkameen valley it falls 2.500 feet, or at the rate of 1,666 feet to the mile. For 2 miles above this—or from the 4.000 ft. cont. ur—the stream occupies a broadly flaring valley, and has an average grade of 500 feet to the mile. This grade ig then virtually constant, up to the headwaters of the stream, on the summit*of the plateau. These figures indicate that Kighteenmile creek is occupying a hanging valley, the original grade of which was about 500 feet to the mile. This grade is preserved in the upper portion of its course, from a point 2.500 feet above the bed of the Similkameen river, This figure indicates the elevation at Wuich the valley hangs, Approximately similar figures can be obtained from *treams on the opposite side of the Similkameen river, near Lighteenmile creek,

The steepening of grades, and the development of hanging valleys in the tributary streams, are not of equal magnitude in streams entering the Similkameen valley at different points. The accompanying photographs, Plates IT] and IV, illustrate this point. In the valley above Hedley the sides #re seen to slope easily and regularly downward from the level of the plateau to the bed of the Stream. Below Hedley, where the valley passes into the Okanagan range, there is

at first a gradual s}- townward from the highlands, as jin the case above Hedley, fo "a sudden change of grade, a rounded shoulder marking , ming of a much steeper grade down to

the stream bed.

In a previous report! it was stated that the cause of these haneing valleys was attributed entirely to glacial action. Differential erosion by the great ice sheet which covered the whole region would have its greatest effects where the ice was thickest, that is to say, over the deep valleys. Concentration of ice in the main valley, after it had left the highlands, with & consequent increase in velocity of movement, would also tend to deepen this valley, while the adjacent country escaped. It was recognized that glacial erosion had had a very marked influence in modifvine the topography of the Similkameen valley, and its present form is the typical U-shape, so characteristic a result of glacial scouring. The spurs and shoulders, also,

projecting into the main valley, had all been truncated and rounded

Summary Report, Geol gical Survey, Canada, 1907, p26:

Ul

NOVOUL Spare Ison

Mp

Me Aln

o

ASA Alsetiaiebaenge lL

HEDLEY MINING DISTRICT: ORE DEPOSITS oO by the same action, and there are no remnants of the older river erosion remaining in the bed of the stream, all these having been removed or covered by the post-glacia! deposition of sediments.

The hanging valleys may, however, have been brought about by totally different causes. The uplift of the Okanagan range, and the adjacent plateau region, may have been so gradual that the erosive force of the Similkameen river was able to keep pace with it by cutting down its bed at the same rate as the uplift. In the case of tributary streams, however, the volume of water of which was small, and erosive force correspondingly weak, the same rate of uplift would be too rapid to allow them to acquire a uniform grade throughout, and sufficient time has not yet elapsed to bring about this result. Consequently, these streams have a sharp break in their grade.

If this theory is correct, it follows that the difference in elevation between the bottom of the Similkameen valley and the point where the change in grade occurs on each stream, represents the minimum amount of uplift that has taken place at each of these points in the late Pliocene times, This difference on Eighteenmile creek, which is about 4 miles from the crest of the Okanagan range, is about 2,500 feet. Evidence in support of this theory of warping, as the cause of the hanging valleys, is furnished by the accompanying illustrations, Plates II and III. These show that hanging valleys are not so high or well marked in the region above Hedley to the west, as they are in the part of the valley below Hedley. The former is in the plateau region where the uplift was relatively lower, while the latter is in the Okanagan range where the uplift was at its maximum.

After carefully considering the ovidence, the present shape of the Similkameen valley and the tributary hanging valleys is believed to be due partly to differential warping, and partly to unequal glacial erosion, each of which has had its effect on the physiographic history of the region. In the development of this topography, the first cause was the rapid cutting down by the Similkameen river of its own bed, concurrently with the uplift of the Okanagan range, and the formation of a narrow V-shaped cajion, as a result. The tributary streams, with their small volume, could not erode their beds fast enough to produce a uniform grade throughout, and a broken grade resulted, with a steepening of the lower portion to approximately the present gradient. On the occupation of this region

9185—3L

og GEOLOGICAL SURVEY, CANADA

bs glacial ice, the V shaped valley of the Similkameen river was used as an outlet for the accumulated ice in the northern plateau

zion, and modification of its shape at once began. 'I'he valley may have been deepened somewhat, and it was probably also widened at the bottom, and projecting shoulders were rounded off. This action would alse tend to accentuate the hanging valley effeet of the tributary streams. Finally, on the melting and recession of the glacial ice, streams overladen with debris carried down and deposited the gravels which help to pive the valley its present shape. 'To thoroughly appr cia toe uction of glacial ice on the topography of the Similkameen valk ¥, one should attempt to recall the conditions 23 they existed at different stages of the glacial period. If we follow DP tee ak. Daly, who has estimated the maximun, elevation of ice in the Boundary section at the height of the glacial period, as 7,500 leet above se a-level, we would get a thickness of about 6,000 feet of ive in the Similkameen valley, while the Leghbouring uplands would only have from 1,060 to 1,500 feet. Differential erosion would naturally result, with the greatest amount in the parts over which there was the greatest load. If, however, we consider the conditions existing both before and after the glacial period was at its height, When the ice only filled the main valley without covering the adjoining uplands, we ean understand the tendency to concentrated erosive action in the deeper valley, while the uplands suffered comparatively little in this respect,

The figures given above for the grade of the Similkameen river indicate swiftly moving water, and strong erosive force. The transporting power of the stream under this grade is such that only boulders, gravel, and coarse sands remain in the bed. The finer sands and suspended aterial are all carried far below this district before they come to rest. Very much heavier grades obtain in the

utaries of the Similkameen riy, r, so that they flow for much of

their courses over bed-rock, In the smaller gulehes, tributary to

Twentymile creek, the grades are - 'Ligh that only a small amount of water is necessary to transport ti2 rock waste doy to the Jarger stream, and in many cases the degre of slope is just about equal to the angle of rest of the rock Was. 2,

Relief.—In general aspect, the higher levels of the ITedley district are almost flat, or gently rounded in outline, The district lies in

a& more cleyated portion of the Interior Plateau region, the genera]

Hedley Mining District! Orf Depostts

features of which have been well deseribed by Dawson, Daly, other geologists. In a broad survey of this plateau region from any one of the higher points, one would hardly suspect the presence ot such deep valleys as those of the Similkameen river, and Twentymil creek. In the general uniformity of level of the plateau, these deep irenches give no evidence of their presence, and consequently con as a great surprise. The elevation of the highest point of the Ifedley district is 6,660 feet above sea-level, that of the lowest point is 1.560 feet, so that there is a total vertical relief of 5,100 feet. The rounded outline of the higher levels represents an older cycle of erosion, antedating the late Pliocene uplift and probably to be referred to the Eocene peneplanation; while the lower levels are the result of a second eyele, when increased pov r of erosion had been given to the stream by uplift of the Interior Plateau region, and a warping of the Okanagan range. The narrow V-shaped cafion of Twentymile creek is the result of 'this second eyele, aided and exaggerated, it is true, by selection by the stream of certain lines of weakness in the rocks. The portion of the valley lving within the limits of the map is very strongly V-shaped, and from 2,000 to 1,000 feet in depth. Its slopes on either side are very steep (about 85°), and characterized by broken rock talus and precipitous bluffs. The tributary gulehes entering the eafion are often nothing more than desp gashes in the mountain side, and though deep, are, on account of their narrowness, almost imperceptible from the opposite side of the valley.

The action of erosion in Twentymile ecafion is very strong, and is equal if not in advance of the decomposition of the rocks by oxidation. Every shower of rain throughout the summer washes down the cafion sides quantities of rock waste. and dislodged masses of rock, to such an extene that it is unsafe to be in the caution at such times.

In a general way, the steepness of the slope is dependent on the solubility of the recks and their debris. The igneous rocks of the district are generally quite as resistant to atmospheric weathering as the sedimentary, or even more so. The granodiorite and gabbrodiorite rocks form the larger proportion of the cliffs; while sedimentary rocks, particularly where they are calcareous, generally show easier grades, In many portions of the eastern side of Twentymile creek the degree of slope is determined entirely by the dip of the

rocks, the one coinciding with the other.

Os GPOLOGICAL SURV ¥, CANADa

Phe upper levels of the district have a totalls different kind ef topography to that found in th canons, and represent an older evel f erosion previous to the Pliocene uplift. IHlere we have forma which are characteristic of the plateau region as a Whole The surmiits are almost flat, of broadly rounded, and the s. Jes of th Vallevs flare out widely Ihe slopes are so gradual that drift will easily rest on them, an ] euterops only secur in the ense ot the more resistant rocks, The more aoluble limestone bands ean generally be ihe lititied, even under the o vering of drift, by slight le pressions or

more graded slopes, while the harder roeks are marked by slight

ldges, The mature re lief of these higher levels ha heen to some extent brought about by glacial action, more particularly that of deposition, The tops of the hills have no doubt been mewhat rounded by glacial erosion, but deposition of debris in the depres:

sions has contributed far more te u reduction of the relief

Climate And 4 Ricultey

The climate ¢ f that Portion of the Sin iTarmer n district in wh I Hedley is sit lated is a very pleasant one. As the yr mn, how 18 one of rather strong relief, the riations of temperature and pre

Ciptation between thy bottoms of the valleys and the higher por tions are yer marked, even at po:nts not far separated from each other. As an illu tration of this, a comparison between observations taken at Hedley and those ¢ tken at the Nickel Plate mine is interesting, These two points, though only 8 miles apart, have a difference in elevation of 1,000 feet. The #eeompanying table gives the average precipitation in inches for each month at thes two points for

the last four years, up to August, 1008:

Hedley. Ni, kel Plate

Inches, Inches, January ,, Sylt> AMRESA re Ten eariG en eee February, , ; ' nm st. oe ee Marolo oo. 5 we 84 ae an, ORF LDS A nae oe , es wo ee 861998 PUR Give: tase sade, Ona err rer Pee fl) EY os Pre aG tad Lae 1:19 August 4 aoa oe : ; 0-89 September, a varies the tee' oo. 1300 October, 8 ; : ve OtBa November Ree ay ; Se eee 1-16 December, Pe FNS a ine i gti ' O-sd

MINING DEISTRIOT © opt DEPOSETS ene es Chis table Wa the average annual precipitation at Led! ! i be 10-79 inches, while that at Nickel Plate is 21-82 inches, or aa ive as much, It also shows that the krenfest precipitation

in the months of May and June, while no particular month ean be

said to be markedly drier than any other, Very little snow

in the bottom of the Similkameen valley from Hedley down-

e ward, so that the total precipitation there must be el irged to rain © At the Nickel Plate, however, snow is known to fall every month of r the year. The climate of Hedley is a distinetls dry one, amd the t camp must be considered to form part of the dry belt of Briti<h ; Columbia, which lies along the eastern Hank of the Coast range of

mountains. The cause of this dry character js found in the faet

that the high and wide Coast range inte reepts all the moisture ear-

ried eastward from the Pacific ocean by the prevailing easterly winds, This dryness is a factor which has to be reckoned with by eom-

panies who contemplate the erection of stump mills in the distriet

for the treatment of the Hedley ores. The supply of water in

Twentymile creck is not even sufheient. to provide power for the

Daly Reduction Company's mill, and they are compelled to conserve

the season's rainfall in a lake at the head of the creek, for use during the dry season. The Similkameen river, however, carries

siderable volume of water the whole year round,

a con-

and this would

undoubtedly be available for the development of power, if mining

operations demanded it. The grade of the Stream is steep, and the

volume of water that comes down in June and July, during the

melting of snows in the mountains,

is very much g.eater than that flowing during the rest of the year,

so that means would have to he devised to meet both conditions.

Temperatures at Hedley have a wide range, thoug

h the mean for the whole year is about 45° F,

The summer mean is about 60° RF. The months of July and August are very hot, and the temperature oceasionally goes up to 100° in the shade. The winters are never very cold, though it sometimes reaches 15° below zero. The average barometric pressure for the year for the elevation of 1,600 feet al sea-level is about 29.95,

ove

Taken as a whole, the country is well wooded, though not thickly. The southern slopes of the hills are frequentl'y

quite open and grass" (See Plate V), and when wooded, have ¢

in open park-like appearance.

410 Geological Survey, Canada

The northern slopes are always timbered, and the eastern and western generally so. The common trees are the vellow pine, fir, black pine, uspen, spruce, and balsam, with some cedar and birch, On account of the dryness of the climate, much of the timber has been destroyed hy forest fires; much, however, js Yet available for use in mining operations,

There are great areas of excellent pasturage for horses and cattle, and buneh grass (Agropyron spicalum ) and pine grass (Koeleria cristata) are the commou grasses, with wild peas and vetches jn certain places,

In the immediate vicinity of Hedley, land available for agriculture is confined to the bottom of the Similkameen River valley. This is also true of the region Iving 20 miles east and west of Hedlev. The valley bottom is from one-half to three-quarters of a mile Wide, and at IIedley has an elevation above sea-level of about 1.600 feet. On either side there is a steep and unbroken rise for at least 3,000 feet higher before the lower levels of the plateau region are reached, and at this level, cultivation of the ground ean be suecessfully earried on only to a very limited extent. on account of the prevalence of frosts throughout. the summer. All agricultural pursuits, therefore, are confined to the main valley, for the tributary valleys are nothing more than V-shaped notehes in which very little soil is found

Farms a seattered all the way through the valley from one end to the other, and are quite sufficient to supply the present needs of the district in vegetables and garden produce. There js room for many more yet; but much of the land is held in trust by the government for the Indians, and if they do not cultivate it. no one else is allowed to.

Various kinds of fruit are successfully grown as high up the valley as Princeton, 95 miles above Hedley. At Tledley itself, apples, plums, and peaches all do well, though only a small number of trees are yet bearing, Pears and grapes are grown a few miles below Hedley. and at Keremeos, Although the area of land available for agriculture js small, its quality is good, and as the population increases, more and more will undoubtedly devote their energies to fruit raising, until this hecomes an important industry in the district.

O15

7

Pe

southern slope

Open

be

Hedley Mining District? Ore Deposits $1

Chapter Iv. General Geology. General Statement,

Regional.

The geolo y of the whole region, of which Hedley forms a part, is very little known as yet. The only geological map of the region, namely, that of Dawson in 1877, is correct only as far as the routes traversed by him are concerned. The region on either side of these routes was then and is still almost unexplored, and little is known of its geology. It is not to be expected, therefore, that the geological formations as defined on that map will be found in all instances to be correct. In a general way, the geology of the region may be outlined as follows: lying some distance to the east of the Hedley quadrangle, and exposed on the eastern side of Okanagan lake, is a series of old crystalline rocks, called the Shuswap series, and representing the old Pre-Cambrian axis of British Columbia. Overlying these rocks on the west 1s a thick series of sedimentary rocks, presumably of Carboniferous age, called the Cache Creek group, and represented by limestones, cherty quartzites, siliceous argillites and voleanic materials. These sedimentary rocks have everywhere been intruded by igneous rocks to such an extent that tittle of them now yemains, and this very often only as isolated patches in the batholithie rocks, completely separated from each other. These igneous rocks appear to cover a much larger area than any of the earlier or later sedimentary rocks, and they represent periods of eruptive activity, extending through a great part of Mesozoic times, and into Tertiary. It is in an area of Cache Creek rocks that the greater part of the Hedley district lies. How large this particular area may be is not yet known, but it is certain that it is completely cut off on the north, west, and south by granitic rocks, and its greatest areal extent s toward the east. In this direction it extends for perhaps 10 or 12 miles, or more, until covered by voleanic rocks of Tertiary age.

Overlying the Cache Creek rocks, as well as the granitic rocks, are small areas of Oligocene sediments containing lignite beds,

42 Geological Survey, Canada

ocenrring in isolated depressions in the older rocks. The best known of these lignite basins is the Princeton sasin, about 20 miles west of Hedley. Other similar areas are known to oceur, which have not yet been studied or mapped. Volcanic effusive rocks of post-Oligocene age overlie the lignite beds, and have a very wide distribution throughout the whole region.

These are the only rocks known to exist within a radius of 25 miles of the Hedley quadrangle.

Loca.

The oldest rocks of the Hedley area are sedimentary rocks, presumably of Carboniferous age, and correlated with the Cache Creek group of Dawson's Kamloops map sheet. These are the only consolidated sediments in the area, and they include, besides the true sedimentary rocks, a great thickness of contemporaneous voleanie materials, generally of explosive voleanic origin. They have been tilted in a general direction toward the west, and they now dip at ancies varying from 15° to 90°,

Eruptive rocks have been intruded through these rocks in the following order: (1) quartz diorite and gabbro; (2) granodiorite. These igneous rocks have been accompanied or followed by many dikes of different compositions, porphyries, lamprophyres, andesites, and rhyolites.

The last and most recent group of rocks in the sequence are the unconsolidated deposits of sand, gravel and silt, of glacial and postglacial origin, which are generally found lying as a thin mantle over the older rocks, or forming the floors of the valleys,

Table Of Formations.

In the accompanying table the different geological formations are arranged in descending order, according to age, and it includes the igneous as well as the sedimentary bodies.

QUATERNARY.—Stream deposits and glacial drift.

TERTIARY.—Granodiorite.

Mesozo1c.—Diorite and gabbro.

CARBONIFEROUS.—Cache Creek group.

(4.) Aberdeen formation.

(3.) Red Mountain formation. (2.) Nickel Plate formation. (1.) Redtop formation.

Metis,

MEDLEY MINING DISTRICT: ORE DEPOSI? Ss 4°

SUMMARY DESCRIPTION OF FORMATIONS. Cacnte Creek Grove.

The sedimentary rocks of the Hedley quadrangle have been correlated by Dr. Dawson with the lower Cache Creek group of the Kamloops map sheet, in which Carboniferous fossila are found. In the entire absence of any determinable fossils here, this correlation has been based entirely on lithological features. It is certain, however, that there is a very marked resemblance between these rocks and those of the original Cache Creek group, and it is altogether likely that if any palwontological evidence is ever obtained, this correlation will be confirmed, Neither a top nor a bottom has been discovered to the series in the neighbourhood of Hedley, for granitic intrusions have cut off the beds at both ends. The various turmatidns which together make up the whole group are conformable with each other. There is, however, an approach in certain portions to littoral conditions, even to the development in them of a small area of fine-grained limestone conglomerate, but even here there is no evidence of an unconformity.

For the purpose of mapping and description, the group has been divided into four separate formations. Although these formations fre generally, though not jn every vase, well-individualized units. the precise horizons of division planes that separate them from each other are matters of arbitrary selection. Without exception, contiguous formations grade one into another, and they all succeed each other conformably. The lines separating the different formations will be described as clearly as possible, later on. A brief characterization of the different formations will first be given, in order to indicate the grounds for an attempted correlation with the typical Cache Creek rocks of the Kamloops map sheet.

Redtop Formation.—The name Redtop, like all the others here given to the divisions of the Cache Creek group, is a local one, applied to the lowest beds of sedimentary rocks occurring within the limits of the sheet. These are best exposed on the north slope of the Similkameen river in Redtop gulch. They consist largely ef siliceous rocks, occurring generally in thin beds, intercalated with bands of limestone at the top and bottom, and with argillaceous and voleanie bands toward the middle of the series. They are seen

Co

Geological Survey, Canada

in the eastern part cf the area to have as a base a massive limestone, called for the sake of convenience in describing it, the Stevenson limestone. This limestone is cut off by the eruptive granodiorite, and only a relatively small exposure of it appears.

The Redtop formation is strikingly banded. due to the rapid alternation of light and dark bands of rock. ':he light bands are generally white or greyish quartzite, while the dark bands are either black argillaceous quartzites or limestone, or beds of black voleanie material. The Redtop formation is characterized in general by shallow water conditions and rapid changes in sedimentation, with many outbursts of voleanic activity.

Nickel Plate Formation—The Nickel Plate formation is so named from the Nickel Plate mine, which occurs in it. In this formation are found all the most important ore bodies yet discovered. In contrast to the preceding formation, which is essentially quartzite, the Nickel Plate formation is eminently caleareous. The base of the formation is represented by the Sunnyside limestone—a greyish blue or dark blue massive limestone. about 800 feet thick, forming a continuous band, which ean be traced without interruption through a large portion of the area. At the top and bottom of the Sunnyside limestone bed there is a gradual transition, by an increase in the quantity of intercalated quartzite bands into the Reltop formation below, and into the middle beds of the Nickel Plate formation above.

The middle of the Nickel Plate formation consists essentially ¢f interbedded limestones, and some quartzites. They are all so much metamorphosed by contact igneous action that it is difficult to obtain a correct idea of their original lithologie character. Many of the beds, now highly siliceous, were undoubtedly originally limestones. Quartzites increase toward the top of the formation, but the topmost bed of all is again a massive limestone coarsely erystalline, and light grey in colour, and ec: ed the Kingston limestone. The voleanic materials of the Red Mountain formation overlie the Kingston limestone; but in places local accumulations of these voleanic beds have been interealated between the Kingston limestone and the remainder of the Nickel Plate formation. cutting off the limestone altogether. When it is separated from the roast of the formation the Kingston limestone is breeciated.

Hedley Mining District? Ore Deposits 15

The top and the bottom members of the Nickel Plate formation represent two of the longest periods of quiet, stable conditions thet

we have in the whole of the Cache Creek group of JIedley,

Red Mountain Hormation,—This formation is made up entirels cf voleanie materials, is not continuous throughout, nor does everywhere overlie the preceding formation. It is found, rather, as local developments and wide lenses, between the Nickel Plate and Aberdeen formations. The rocks consist essentially of fravmental voleanie materials, making up a succession of beds which appear to have been deposited in water, The materials of whieh the beds are made up are of very variable fineness, from microscopic particles to large, coarse blocks, In contrast to the banded appearance of the other formations, these rocks are characteristically massive. They contain a great deal of iron sulphides, and, in consequence, weather easily to a dark reddish colour.

This formation attains its maximum development on Red mountain, where on account of its great resistance to erosion, it forms

steep conspicuous bluffs and precipices,

Aberdeen Formation. ~The \berdeen formation is so named because the beds are best seen in the neighbourhood of the Aberdeen ridge and below it to the bed I'wentymile creek. This is made up of a very thick accumulation of true sediments, and some volcanic materials, the former consisting of bands of dark blue and white limestone, light coloured quartzite, and dark siliceous argillites, These separate beds are usually thin, and the frequent change from dark to light gives the exposures a beautifully striped and banded appearanee. The light coloured bands are usually quartzites or white limestones, while the dari bands are either dark blue limestones, siliceous argillites, or fine-grained black voleanie tufts, The metamorphism of some of the limestone bands to garnet or epidote often introduces shades of green, brown, or dark red in the exposures, The thickness of these bands js generally very little more or Jess than 1 foot, and the banded character of the whole series is well brought out in the steep cliffs of Stemwinder hill, overtesking the town of Hedley, and particularly when the rocks have been washed clean by recent rains. The attitude of the Aberdeen formation js general), steep, and the rocks all dip at very high angles to the west, or are vertical,

46 Geological Survey, Canada

The succession in descending order, general lithological character, and approximate thickness of the different formations, are summarize tin the following generalized table ;—

Generalized Tabuiar Seetion of the Cache Creek Group at Hedley.

a Feet. +). Aberdeen Formation.—Consisting ot interbanded cherty

quartzites, limestones, siliceous argillite, and voleanic materials, ail in thin beds, indicating rapid changes in sedimentation, and frequent outbursts of voleanic activity 3000+

(3). Red Mountain Formation.— Consisting essentially of beds of voleanie materials, tine tufts to coarse breccias, regularly bedded, and indicating deposition in water. Essentially local and quickly pinching out between true sedi-

MCUtS: -MIOMIM Uttsig. des de oes ca BCH Grnctrme reysrs N09

(2). Nickel Plate Formation,—( 'onsisting of massive limestones at the top and bottom, with interbanded quartzites and siliceous limestone in the middle.. .. a ReMatie ares ulna tee OOO

(1), Redtop F ormation.—Consisting of interbanded limestones, cherty quartzites, siliceous argillites, tuffs, and some breecia, resting on a massive limestone, the base of which is cut off by granitic intrusion .. prenkimiem: be he ere on heise) ak OMS

Hedley Mining District: Ore Deposit 4 47

Generalize? Columnar Section of the Rocks of the Hedley Sh,

Aherdeen Formation. Interbanded limestones,

Guartzites, argillites, and voleanie materials,

Red Mountain Formation Voleanic materials, tuffs, bre

Clas

Kingston Limestone,

Massive limestone and banded limestone ites, thin-bedded,

inter Nickel Plate Formation -— and quartz-

Sunnyside Limestone,

Redtop Formation -— 4 uartzites, argillites, vok ante

Mhhit- (terials, and some lithestone,

Stevenson Limestone,

ts GEOLOGICAL SURVEY, CANADA

Igseols Rocks,

With the exception of the pyroclastic rocks associated with the Paleozoic sediments, all the igneous rocks of the district are in trusive in origin. According to form or method of intrusion, they might be classed as batholith, stocks, apophyses, and dikes and rheots. All are found in intrusive relation to the Cache Creek sediments, and all were intruded after deposition had ceased. The order of intrusion of the larger bodies has been marked out in detail, but the relation of some of these bodies to the dikes is yet in doubt, as they have not been found in contact with each other,

The oldest of these igneous rocks is considered to be of Mesozvie age; the reasons for placing them here will be discussed later. This is the diorite-gabbro complex, and its rocks occur in thin, distinct, stock-like masses, and jn several intrusive bodies of irregular form, besides in large numbers as apophyses from those. The most common rock of this composite formation is a diorite, which, with the addition of quartz, becomes a quartz diorite. Its constituents are plagioclase feldspar, and green hornblende, with a smaller proportion of orthoclase and quartz. With this is associated a gabbro which is intrusive into the diorite, but only very slightly younger in time of intrusion. The gabbro is of uniform texture and composition, and is white, or very pale greenish in colour. It is composed of plagioclase feldspar, and very pale greenish pyroxene, which proves to be diallage. There is a close consanguinity between the diorite and the gabbro, and it is difficult to separate them on account of transitions between them. This transition is more apparent in the apophyses from the main bodies. In the massive forms, while a transition is sometimes seen, it is more common to find a contact, This contact is of such an indefinite nature that the conclusion was drawn that the galbro was intruded into the diorite before the latter had quite solidified, and while it was still in a plastic condition, The whole formation is considered to have been at one time one homogeneous magma. which by differentiation separated into different parts, of which the quartz diorite is one extreme, and gabbro the other. These rocks cover a large area in the district, and are of great economie importance as being concerned in the formation of the ere hodies.

An igneous reck cf leter dete than the dioriu -gabbro formation

is a granodiorite, which as been referred to Tertiary age. Though

HEDLE MINING DISTRICT! ORE DEPOSITS a)

in many places concealed by drift and gravel deposits, this probally covers a much larger area than any of the other igneous bodies. It appears in this district as part of a great batholith, whieh has a wid areal distribution to the south and west. It is a rather basie granodiorite, and is more nearly related to diorite than to granite. It js a uniform rock of coarse Sranitie texture, and even grain, and is made up of orthoclase and Plagioclase feldspar, the latter in excess, and quartz, hornblende, and biotite.

The dike rocks of the district are of various kinds, and of different ages, some being cut by the ranodiorite batholith, and others intrusive into it. Lamprophyre dikes belong to a period earlier than the granodiorite, but later than the diorite-gabbro, Aplites and quartz porphyries apperr to be connected with the granodiorite intrusion, while some soft greey sndesites are later than this event. No uniformity of trend in all the dikes can be made out, but in the younger ones there is a tendency to parallelism in a north and south direction of strike.

Quaternary,

The Quaternary deposits of the Hedley area consist entirely of

unconsolidated materials of glacial and post g'acial origin. The former are found as a thin mantle overlying the older rocks and are seen everywhere on the higher levels, The deposits of post-glacial origin are found as stream deposits in the bottom of the valleys, These form a very thick deposit, into which the present streams are incising their channels, forming well marked benches to denote the different levels at which the ater formerly stood, They are not of much economie importance, and consequently have not been very closely studied.

Detailed Description Of Pormations, Redtop Formation,

Distribution.—The Redtop formation includes all the sediment.cv rocks inside the sheet lying below the base of the Sunnyside lim, stone. The contact with the Sunnyside limestone is a fairly welldcfined line, which ean generally be identified when exposed. The

lower boundary of the formation, however, is arbitrarily fixed at the 9185 —4

a0 GEOLOGICAL SURVEY, CANADA

Contaet of the eruptive granodiorite, and it ds impossible to say how great a thickness of these beds originally Jay below the lowest bed now en,

'The Redtop beds are most exten vely developed in the southeastern portion of the sheet. They direetly underlie the Sunnyside limestone, but in the western part of the sheet the base of the Sunnyside limestone is not exposed, so that the Redtop beds are not seen. Along the eastern border, also, where this occurrence would he expected, they are largely covered by drift; but here, one or two smal' outcrops of igneous rock indicate that they may be cut off in place almost up to the base of the Sunnyside limestones,

The best exposures are seen in the Redtop gulch and on the face

Striped mountain, overlooking the Similkameen river, where their banded appearance, accentuated somewhat by sheets of igneous material, suggested to Dr. Dawson the name Striped mountain.

The Redtop beds have not yet yielded anything of economie

rortunce in the way of ores, but there is no reason to believe that

ider favourable cond¥tions of igneous intrusion the formation should always be barren.

Thickness.—The best estimate of the thickness of the Redtop formation is obtained from an east and west section across from Striped mountain to Eighteenmile creck. The thickness obtained here, however, can only be an approximation, as for a great part of the distance the beds are covered by drift, and it has to be assumed that the dip in this part is constant throughout. This assumption might probably be borne out by the facts; but there is also some close folding to be seen in Redtop guleh, which may indicate a repetition of beds in the part that is covered by drift. The minimum

value obtained for these beds is 1.200 feet.

Lithology.—Owing to the lack of any continuous exposure, the succession of strata cannot be worked out in detail. The lowest bed ot this formation is a massive limestone, which is truncated by the eranodiorite intrusion. This limestone is light grey in colour, eranular, and in places crumbles easily. It is best seen on the west side of Eighteenmile creek, overlooking the Similkameen river.

Above the limestone the strata are covered for some distance, but when again exposed, they are seen to have changed from ealeareous to highly siliceous rocks, The bulk of this middk portion

ef the formation consists of very fine-grained che rty quartzites,

HEDLEY MINING DISTRICTS ORE DEPOstts rf

with which are interbedded layers of voleanie material, and

heeous argillites, The cherty quartzites vary in colour from te dark erev, and Sone afe light reer, ] if leds, i rule, aie heavy, generally only a few mencs or even a fraction of ath at thiek, and show rapid changes in sedimentation. On account the readiness with whieh they break up, they give rise to talus slope mode up of very small fragments,

The voleaniec beds interealated with these echerty quartzites are themselves very siliceous, of varjable thiekness as @ rule, not contintious over large areas. In the Redtop gulek, some thin red dish bands, often less than 1 inch in thickness, re thought to be ef voleanie origin, and it is considered that they ar mply local aecumulations of astematerial, aid down under water contempor rneously with the enclosing quartzites, Afterwards, these ash-beds were compacted, and later still, altered hy metamorphie action, eon neeted with igneous intrusions, which alse affected the adjoining

beds,

If conti these middle quartzitie beds should again be found on the we dge of the map below Sunnyside No, 1 rv-hol

and near the rks of Eighteenmile creek. Nearly all of this part, however, is covered with drift, and the fey exposures of rock whieh appear, only tend to make the study of them confusing, Outerops of a very hard siliceous breccia, too small to give ans idea of its stratigraphic relations, have been exposed by miners in their prospecting operations in this portion of the district. This breccia may be a bedded voleunie deposit, having its counterpart jn the thin hands of voleanic material in Redtop gulch. Betwee the

forks of Eighteenmile creek, however, where it is again exposed,

though outside of the shect, the attitude of the breeeia is almost Vertical, and it here suggests a formation by intrusive contact with igneous rocks. In other portions of the district, particularly at Cercral station, on the gravity tram-line, and north of the Nick Plate mine, breeeias of undoubtedly explosive voleanie origin, but ' vhich are interbedded with true sedimentary rocks as if laid down f in water, are well exposed: so that it is probable the breccia above referred to is of similar origi Above the essentially quartzite heds of the middle portion of the Redtop formation, there is a gr leney to a change sedjmentation to clearwater eond to The transition was not si; 9185 —44

52 Geological Survey, Canada

limestone, but rather a series of rapid changes in sedimentation, during which there was an alternation of siliceous and culeareous beds, with each time a stronger tendency toward the formation of calcareous beds, until a point was reached when the changes ceased, and conditions remained stable for a long period of time, to allow the deposition of the Sunnyside limestone. As a result of these changes in sedimentation, we have bands of limestone from 6 inches to 1 foot thick, interbedded with the other rocks.

This period was not without its intervals of vuleanism, and we find beds of fine-grained black tuffs, and some breecia intercalated with the limestone and quartzite, denoting outbursts of voleanic activity. Interbedded 'vith all of these are other black layers, which 'ire now very siliceous, but which may originally have been largely argillaceous in composition.

The uppermost bed of the Redtop formation on Striped mountain is seen to be a breccia, in places about 2 feet thick, which contains fiagments apparently of 'the lower bed, much metamorphosed and cemented together with a caleareous cement. Even in some of the small limesteae bands, one occasionally secs small fragments of foreign material, apparently voleanie ejectamenta, embedded in the limestone, indicating that e in the quiescent periods of limestone formation there was voleanic activity going on at no great distance.

The alternation of beds, and the consequer* banded ppearance of the upper Redtop beds, are well shown on Plate VI.

A peculiarity of some of the upper limestone beds of the Redtop formation, as well as of some of those of the Nickel Plate formation above it, is their emission of a futid odour of sulphuretted hydrogen, when struck with the hammer.

The attitude of the whole formation in general shows a fairly uniform dip of about 85° to the W N W. When examined in detail, however, one notices a few examples of complete folds of small magnitude, particularly in subsidiary cations on the west side of Redtop gulch. Here also are some minor faults, with throws of a few feet, which strike almost north and south. The whole formation has suffered considerable metamorphism as a result of orogenic movements, but a great deal more contact igneous action.

Microseopie Characters,—When studied microscopically, the rocks

of the Redtop formation furnish little information that is not already chtuined from a field study of them. This is especially true of the

ion,

Ous

yn

Puate

HEDLEY MINING DISTRICT! ORE DEPOSITS ayes

caleareous members of the formaticn. In the case of the siliceous and volcanic members, it is practically impossible to get away from the effects of metamorphism by contact igneous action, so that the microscope simply reveals what the characters of the beds now are, without giving much hint of what they originally were, before metamorphism. Sections of the light-coloured cherty quartzites show a rock of exceedingly fine grain, made up of quartz, epidote, and iron sulphides. The epidote occurs either in small isolated individual grains, or in irregular areas made up of an aggrezation of small grains. Some garnet is occasionally associated with the epidote. The bulk of the sections, however, appears to be made up of silica, either as small angular grains of quartz, or as an almost isotropic mass of chaleedonic silica, forming the ground-mass in which the epidote and quartz are embedded. The chalcedonie silica is probably of secondary origin, and may have replaced se of the original constituents of the rock. It is difficult to s-5 what the original composition of these rocks may have been, but it is certain that they were to some extent calcareous, and also somewhat siliceous. They were undoubtedly rocks that lent themselves very readily to alteration by contact metamorphism, for metamorphism has extended farther into these rocks than into the limestones that are jnterstratified with them. This may have been due to greater poresity, and it is quite possible that the original rock was a loose tine-grained voleanic tuff, that wis later silicified and compacted.

A characteristic feature of these cherty quartzites is the oceurrence in them of very small fissures, which are, as a rule, filled with guartz, but which often contain some calcite in addition. Oceasionally these fissures are filled with well erystallized laths of feldspar.

Fine-grained reddish rocks, with a harsh feel, interstretined with the cherty quartzites, are taken to be metamorphosed tu#s, T!.e thin section shows them ta be very fine-grained, and made up small angular grains of quartz and feldspar, and lath shaped erystais of brown mica. Some of the grains are almost isotropic, and might be glass, more or less devitrified. Tron ores—both pyrite and magnetite —are very abundant.

The argillaceous rocks interstratified with te above are scen under the microscope to be very siliceous, and contain erystals of feldspar. An opaque and probably carbonaceous substaice js abundant. showing a tendeney to flow structure. by curving around the quartz and feldspar grains.

od

Gleologicat, Survey, Canada

The massive limestone at the base of this formation is only

ven though it is cut by the large mass of

base of the hill!' The siliceous and tufaceous beds, on the other hand, which make up the bulk of the highly metamorphosed, the ever practically the whole of these

slightly metamorphosed, e

franodiorite forming the

centre of the formation, are

metamorphisin extending

beds seen.

Nickel Plate Formation,

Distribuiion.~

-The Nickel Plate formation is much better de than the unde

rlying Redtop formation, bers are two fairly

tined Its top and bottom mem-

distinet and individualized beds ot

Nassive limestone, the lower being

known as the Sunnyside limestone, and the upper as the Kingston limestone, The complete section from the base of the Sunnyside limestone to the top of the Kingston lime-

ep bluff overlooking the town of Hedley,

on the eastern slope of Twentymile creek, Over a great part of the area to the east

of this the upper limestone bed has either eroded away, or has been so chan to be unrecognizable,

stone is only seen in a ste

een ged by contact metamorphism as In the northern part of the ton limestone is completely separ Nickel Plate formation by loeal © material, und appears, after an interval on Red mountain of several hundred feet, as a brecciated bed. Overlying the Kingston limestone at this materials.

sheet, the Kingsated from the remainder of the accumulations of yoleani

place are more voleanic sheet the Nickel Plate

deen formation above,

In the northwestern part of the 'ormation passes conformably into the Aber-

without the intervention of tha

voleanic materials of Red mountain

Which here pinch out.

The Nickel Plate formation, while not be the Redtop or Aberdeen, attains a muel than cither of these,

ing as thick as either 1 sTeater areal development It forms a broad band entering the sheet at the northeast corner, and passing diagonally across it to the southwest, where it is cut off by the granodiorite at the junction of the Similkameen and Twentymile valleys.

Economically this has proved to be the most important form:

it are the important ore bodie Nickel Plate and Sunnyside mines,

ition in the whole camp, for in

3 of the and other promising prospects Twentymile creek, import nee are to be looked for in the r

on the eastern slope of Other discoveries of

ocks of this formation,

nly s of tuthe i0r-

HEOLEY MINING DISTRICTS ORE DEPOS[ TS oe

Uhickness—The work of making an estimate of the thic

of this formation ia complicated by the great number of intrusive sheets of igneous rock which are found in it. Loeal aceumulations of volcanic materials are also wedged into the upper members, ani unless all these are eliminated from the total obtained, the result is a figure to which the formation js by no means entitled, A. seotion east and west through the steep bluff overlooking the town on the east side of Twentymile creek gives a result that is, perhaps, more nearly correct than can be obtained elsewhere in the eamp, for here voleanie beds are entirely wanting, and intrusive sheets are so few and well exposed that their thickness can be estimated with reasonable accuracy. This section gives a total thickness for the Nickel formation of about 900 feet, of which about 300 feet must be credited to the massive Sunnyside limestone member.

Lithology.—The Nickel Plate formation shows lithologically much greater homogeneity than either of the other two strictly sedimcntary formations. Voleanie materials as interealations ane noticeably wanting, and the whole formation is essentially calcareous.

On account of erosion of the upper members—or truncation of these by igneous intrusions—it is almost impossible to get a complete section. On the eastern slope of the Nickel Plate mountain, where one might expect to get the best section, both on account of the dip, and on aceount of the smaller number of igne. ts intrusions, the Leds are generally covered by drift, and exposures are rare. On the western slope of the mountain, going down to Twentymile creek, the dip of the rocks almost coincides with the slope of the surface, so that only the upperm.st beds ean be seen. A sharp break in the regularity of this slope, however, occurs about 1,300 feet above the led of Twentymile creek, end a ste p precipitous bluff is formed which gives an excellent exposure of a great part of the Nickel Plate formation. (See Plate VII).

A three-fold separation of the whole Niekel Plate formation might easily be made on lithologie:] grounds. 'These divisions would consist, first, and in the lower part, of the massive limestone called the Sunnyside limestone; seeond, a middle division of alternating bands of limestone and quartzite, with the limestone greatly preponderating, and at the top a third division, consisting again of a massive limestone known as the Kingston limestone. These

divisions are not separated from one another by any well-defined

on GEOLOGICAL SURVEY, CANADA

lines, but there is rather a gradual transition by increase or decrease of quartzite bands from one to the other, so that different observers might not select the same division plane,

The lowest member of the formation is the Sunnyside limestone, which has a thickness of about 300 feet, The physical appearance of the limestone varies from a light grey coarsely erystalline rock, which crumbles readily, to a more compact dark blue variety, the latter predominating in the upper portion of the bed. Some very thin, irregular, and not continuous layers of cherty rock are occasionally interbedded with it, and these are rarely more than an inch or two in thickness, Toward the top, the Sunnyside limestone is white and coarsely crystalline in bands. This limestone is one of the most distinctive bands in the whole camp, and was very useful in tracing out the horizons adjoining it. It forms bold cliffs on the face of Striped mountain: but on the eastern slope of the mountain its outline is only marked by a gentle even slope, contrasting with the holder topography of the more resistant rocks,

The Sunnyside limestone represents one of the few periods— and probably the longest—ot quiescence in the whole history of the Cache Creek group of Hedley; and whether the cherty layers represent a change in sedimentation or voleanic disturbance, or merely metasomatie replacement, the length of time required for the formtion of these bands is relatively short.

The middle division of the Nickel Plate formation has an approximate thickness of 500 feet up to the base of the Kingston limestone. This portion of the formation lends itself much more readily to contact metamorphism than either of the adjoining diyisions, and its mine ral composition has been so changed thereby, that it is impossible to obtain a correct idea of its original character. It forms the upper portion of the Nickel Plate mountain above the Sunnyside limestone, and holds the Ja rge ore bodies here being worked. It is, however, greatly intruded by dikes and sheets of igneous rock, which have doubtless induced some change in Composition, as wel] as to some extent destroyed the original structure, Following these beds toward the south and west, past the Yale Mining Co.'s tipple and Central station, and down to the steep bluff on Twentymile creek overlooking the town, frequent outcrops are obtained, many of which are only slightly altered by contact metamorphism, and from these some idea of their original character may be derived.

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Dortication,

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te

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Nickel P

thie

ot

Clitfs formed by rocks

dele

MEDLEY MINING DISTRICT; ORE Dy} POSITS ws

In general, the division is caleareous throughout, but is divided by bands of quartzite, which vary jn thickness from 1. or 2 inches up to 8 or 4 feet. These quartzite bands are yt always continuous, and are thicker in certain places than in others. As an example, the que 'ite bands are noticeably thicker on the top of the Nickel Plate mountain than they are below the Kingston mineral claim, but in this case it is not absolutely certain whether these are true quartzites or criginally calcareous beds which have been replaced by silica derived from a stock of dioriie thrust through the beds. When these alternating bands of limestone and quartzite have not been subjected to contact metamorphism, and the bedding planes destroyed, they resemble portions of the Aberdeen formation directly below the Sunnyside limestone.

A characteristic exposure of this phase of the formation is shown in the accompanying photograph, Plate VIII, when bands of dark blue limestone about 6 inches thick 'alternate with white quartzites of about the same thickness. In the upper portion of this division, both the quartzite and limestone bands are much thicker, showing a longer period of stability between the times of change in sedimentation,

The middle division of the Nickel Plate formation is overlaid, hoth at the Central station and in Murray caiion, and on Red mountain, by local beds of voleanie material which separate it from the uppermost member of the formation—the Kingston limestone. The normal sequence of sedimentation is seen in Red Eagle gulch, where there are few voleanie beds, and the Kingston limestone directly succeeds the banded rocks of the middle division. Going northward, however, across into Horsefly gulch, not more than 2,000 feet away, thin, dark, reddish layers, presumably voleanie ash material, begin to appear, intercalated in the strata below the Kingston limestone. These layers are taken to be the thinned out edges of the voleanic beds which are so highly developed in Red mountain below the Kingston limestone. It is not possible to trace these beds out continuously to verify this, because a large intrusive stock of diorite intervenes; but if these beds'are of the same horizon, it would locate the souree of these voleanie materials somewhere to the north of Red mountain.

A. satisfactory description of the Kingston limestone is hardly

possible, on account of the lack of good exposures, and from the fact that there is no portion of the whole Cache Creek group of the Tledley

os GEOLOGICAL SURVEY, CANADA

"istrict that has suffered so much alte ration and deformation as this limestone. Over a great part of the area covered by the Nickel Plate formation, it has been completely eroded away, and, where it still remains, it has been folded, faulted, breeciated, or thoroughly silicitied, so that its recognition di pends almost wholly on its position relative to the other rocks. Perhaps the best exposure is seen in the le guleh; but here, again, it has suffered

Upper portion of Red Bag

-o much metamorphism from igneous rusions that only a general idea of its thickness and Original lithologieal charaeter ean be obtained. On its lower side, it has no well-detined bounding plane, and it is only distinguished from the upper members of the middle division of the Nickel Plate formation by its greater thickness,

Megascopieally, it is a light grey to dark blue rock, frequently coarsely crystalline, and in places of a loose texture, so that it crumbles readily to a coarse sand, It has not a uniform composition throughout, but contains some thin bands of cherty rock, and others of fine black tuffs. These cherty bands are interbedded with the limestone itself, and were probably formed with it; and are not to be confused with' certain irregular cherty masses which occur in the limestone near the contact of diorite, and which are probably due to an introduction of siliea from the ignoous rock at the time of intrusion,

Like all the rest of the sedimentary rocks, this limestone hus a general dip to the west, of from 12° to 30°, On account of its texture and solubility, it has a tendency to form smooth and even slopes and rounded shoulders,

As stated above, it was found impossible to follow out the Kingston limestone in the direetion of its strike, because in one direction it has been eroded away, and in the other it has been cut off by eruptive rocks. Northward of Iforsefly gulch, diorite has interrupted its continuance for some distance, and when the sedimentary rocks again appear there is diffieulty in identifying the Kingston limestone, on aceount of the metamorphism which it has suffered.

A few hundred feet to the south of Climax bluff a very highly altered band of rock occupies the hi rizon equivalent to the Kingston limestone. This rock was undoubtedly originally a limestone, but has been metamorphosed and silicified hy contact with the igneous rock to the west of it. The metamorphism has taken the form of a recrystallization, and the formation of large crystals of quartz, cal-

+ this ickel re it ighly icon n the fered neral n be lane,

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ae

EDLEV MINING DISTRIOT: ORE Pb it

cite, garnet, epidote, and some tourmaline ind aninit Wher hax been much weathe ring, the harder mineral stitids tint relief to the softer, Large prismatic evystals of quartz forte a work embedded in the eak ite. Garnets are well indevidualized, stand out very prominently, while the epidote occurs in bunely green radiating fibres, On large outerops, there js strong evider of breeeintion, This breeeiation probably took place before the alter ation by contaet metamorphism, and js consequently now somewhat obscured by it

Continuing northward from Climax bluff alone a hurrow ridge ealled Windfall ridge, we tind a peculiar breeeiated limestone, and this, on measuring its he ight above the well-detined Sunnyside lime stone, is found to oceupy the horizon equivalent to tne Kingston limestone, Where first sven, directly north of the Nieke! Plate gloryhole, the breceija bed is made up of angular limestone fragments, varying in size from a few inches to several feet in diameter, These are cemented together with an igneous cement, which, how: ever, forms a very small Proportion of the whole rock, but which stands out in marked relief to the limestone. The breeeia bed has cistinetly stratified appearance, when viewed from a distanee, but

vuien examined in detail, the stratification is not so apparent, boVowing the breeeia bed along the ridge to the north, thi # material changes from andesitie to calcareous, and we 'ants of a small band of fine-grained conglomerate interwith it. This conglomerate js made up of simul] rouided F Martz in a caleareous cement, In weathering, these 'od out in marked relief, but a fracture often breaks )s 's3 the pebbles, as well as the cement. In places, merate appears as narrow streaks not more than 2 ineh: ?aicuer wide in the limestone, generally, though not aly ays, paralle] to the bedding planes of the limestone. The whole occurrence is peculiar and difficult to account for; hut, if not due to a met somatic replacement hy siliea, may re+resent an approach to shore line conditions at the time of the formation of the limestey ©, but before the breeciation occurred, From Windfall ridge, the limestone breecia forms a well marked bed, lying on top and below beds of voleanic material, which ean Ix traced right aercss Red mountain into Bradshaw eaion. Th,

Voleanie beds both above and below it are not brecciated, and it

60 Geological Survey, Canada

probable that the brecciation of the limestone was effected by hot volcanic rocks alongside it, or the compression and sinking of the loose voleanie tuffs on which it rests.

Leyond, end to the west of Bradshaw canon, the whole formation is faulted down, and when the Kingston limestone again appears, it is seen to have resumed its normal massive character, and no brecciation is apparent in it. The overlying voleanic materials have also pinched out, and the limestone is directly overlaid by the rocks of the Aberdeen formation. On account of the absence of brecciation to the west of Bradshaw caiion, the belief is strengthened that the breecia-

tion was due to the presence of the accompanying voleanie rocks.

Microscopic Features.—Sections of the massive dark blue Sunnyside limestone show the rock to be made up almost entirely of small vrains of calcite. Dark, opaque, probably carbonaceous matter, is distributed through it in such a way as to give an appearance of flow Structure to the section, A few quartz grains, hornblende crystals, and seme chlorite, as well as some iron oxide, complete the constituents of the section.

The white crystalline limestone which forms the top of the Sunnyside limestone member is seen te be composed of large ealeite crystals, with quite a large proportion of quartz grains, showing that the clearwater conditions which prevailed during the deposition of the Sunnyside limestone were gradually changing to the conditions which prevailed during the middle of the Nickel Plate formation, when altermating bands of quartzite and limestone were laid down. Pyrite, pyrrhotite, and iron oxides are sparingly seen in sections of the white limestone,

Unaltered sections of the banded rocks of the middie portion of the Nickel Plate formation are difticult to obtain, and those that we have give little additional information. The siliceous bands, however, are shown by the sections to be of two kinds. One is a typical quartzite made up of small rounded grains of quartz; while the other, which is also found as thin bands in the massive limestone members, is a very fine-grained reek, composed of almost isotropie silice, with a distinetly banded appearance. Associated with this silica are small grains and aggregates of epidote, and a few sinail crystals of arsenopyrite.

The question of the metamorphism of the Nickel Plate formation

is one which is intimately connected with a study of the ore bodies,

Hedley Mining District! Ore Deposits 61

and as all the known ore-bodies lie in this formation, a detailed description of the metamorphism it has undergone will be deferred to the chapter on economic geology. It will be sufficient to say at this time that, contrary to the findings of some other geologists, it is certain that the impure limestones, and those interbanded with quartzites, have suffered more intense and widespread metamorphisi than the purer massive limestone members of the top and bottom of the formation.

Red Mountain Formation,

Distribution.—The Red Mountain forination embraces a consid>r- tble thickness of volcanic materials lying in and ai the top o1 the Nickel Plate formation. These attain their greatest development in the long steep ridge locally called Red mountain, which forms a shoulder between Murray ecafon and Bradshaw cafjon. A smaller detached area of volcanic rocks corresponding to the lower beds of the Red Mountain formation is also found a short distance: to the south of Central station. These may originally have been connected with the main body, and later separated by erosion of the connecting portions of the beds, but this is not necessarily so, for the voleanic formation is always a local development, and the rocks of the Central station may have been derived from an entirely different source. The lithological resemblance of the rocks of the two areas, however, points to derivation from a common source. These rocks do not represent a single period of continuous uninterrupted deposition of voleanie materials, but rather two periods, since there is a break about half-way, when the voleanie activity which produced these rocks vas arrested, and normal conditions of aqueous sedimentation held for a time. During this period, the Kingston limestone of the Nickel Plate formation was deposited, sometimes on top of the earlier volcanic beds, or where these wedge out, directly on top of the underlying members of the Nickel Plate formation. Consequently, there are in reality two distinct periods of vuleanism represented in the voleanies of the Red mountain and separated by the Kingston lime- Stone. It was thought best, however, to group all these voleanic rocks formed during these two periods under one name, because they are made up of rocks of very similar composition, and were deposited under apparently identical conditions.

There are many other voleanie beds interstratified with the sedi-

mentary rocks, formed at various periods in the history of the Cache

eoeae si

GEOLOGICAL SURVEY, CANADA Creek rocks, but they are generally of small vertical extent, and pinch

The rocks of the Red Mountain of much greater thicl:ness than any them, are only of lo J

zontal direction,

out quickly in a horizontal direction, formation are of these, but like 'mportance, and do not extend far in a horiyut wedge out quickly in the true sediment

ary rocks, -\s an instance of this, we finc

lin Red mountain a thickne

35 of about 1,000 feet of voleanic rocks: but on following them out to the west

und southwest, they quickly dee

or 2

rease in thickness, until, at about 14 miles, they die out altogether.

Thickness.—From the foregoing it will be seen that the thicka: obtained for this formation will de which they are measured.

pend entirely on the section across On the upper part of Red mountain, where they attain their greatest development, it has been estimated that they reach a thickness of at least 1,000 feet. Of this about 400 feet lie below the Kingston limestone, : above. Toward the west and southwest the .. ckness quickly decreases, until the rocks pinch out altogether. Toward the northeast they appear to inere¢g

the remainder

ase, but here they have been removed by erosion, or cut off by later igneous intrusions. At Central station the voleanie 'eds below the Kingston limestone

thickness of these which now rem

Lithology.—The

are alone represented. end the ain is about 250 feet.

Red Mountain formation j and is consequently clearly disting aqueous sediments of the other formations, with the true sedimentary formations, because it is believed that the ereat bulk of the beds is made un deposited under water in the

essentially of yolexnie origin, wished from the true

it is, however, treated

of voleanic materials that were

form of ash or other explosive ejectamenta. Some undoubtedly true

calated in these beds, but thes

vole anie aqueous sediments are inter- e are of relatively small extent.

The lower portion of the Red Mo

untain formation, which is most easily studied in

the area near Central station,

consists essentially of tuffs and breccias, evenly

and distinctly bedded and

occasionally interstratified with cherty quartzites,

A section across these heds shows at the base, beds of breccia of variable thickness and perthe upper portion of the Nickel Plate formation. The breccias are comp

sisteney resting on the quartzites of

sed cf angular fragments

ks, interbedded in a tuff matrix, but

sometimes cemented together by a caleareous cement. Above these

are fine-grained, black and reddish tuffs

of siliceous and caleareous roc

: With which are interstratified

Hedley Mining District: Ore Deposits 63

some thin bands of quartzites and argillite, though the voleanic beds greatly prepondcrate. The reddish tuffs are frequently coarse-grained enough to pass into breccias, and are always highly mineralized ith write and arsenopyrite, which are seen in crystals or in small veins, ihe tufts are also ent by small siliceous stringers. Higter up the reddish tuffs are replaced by very fine-grained glistening black tuffs, whieh break with a eonchoidal fracture. Above these are porphyritie igneous rocks, conformable with the bedding of the tuffs, dark reddish in colour and difficult +o distinguish from the red tuff beds. On the tep are more breccias, interbedded with tutis. The breccias are again made uy of angular fragments of limestone, quartzite, and reddish tuffs. embedded in an apparently tui? cement; and these beds are sometimes seen to pass hy a gradual! traasition, by decrease in sive and number ot fragments, into tho fine-grained reddish tuffs. vt Red Mountain area the ower beds are very similar to those of the Central station. and consist essentially of roaddis!, tuffs and breccias, and fine-zrained black tuffs, interstratified with very thin silicgous bands. These beds are very regularly bedded, and have a thickness of from 15 to 30 feet each. Above the brecciated Kingston limestone, the Red Mountain formation is composed of very hard siliccous fine-grained tufts, varying in colour from dark to light grey and pale green These show distinet evidence of Stratification, and from the fact that they are : terbedded with some quartzite and limestone, were very probably laid down in w ater. They have been somewhat metamorphosed, with deveiopient of slaty cleavage in places. The eoarser varieties have a very harsh fee] on the fresh fracture, and sore of the finer-grained siliceous varieties break with a conchoidal fracture. These rocks contain a great deal of pyrite and arsenopyrite, as well as prrrhotite, and nsequently weather red from the oxidation of the iron. Interbedded with thes: distinet!y clastic rocks are others the mode of origin ef whieh js

totally different These are ery stalline igneous rocks of a diesritie

t l grey in colour, They are dis-

composition, tine-grained and di

tinetly bedded with the volcanic tuffs, and may be intrusive sheets injected along the bedding planes of thy tuffs, or they may be con-

solidated lava flows, that have ber n compressed and metamorphosed.

They carry an abundant peculiar bluish green hornblende . Which is peculiar to these reeks alone, and is net found in any others. Besides hornblende they contain iastioelase, xene, some quartz

and much pyrrhotite,

Geological Surve Y, Canada

The upper portion of this formation passes sition into the true sediments of the Aberdeen formation above, where the tuffs become much finer in grain, and the beds become gradually thinner and thinner until they are entirely re the quartzite and limestones of the

The upper beds develcped slaty cleay

YY a gradual tran-

placed by overlying formation. of the Red Mountain formation h:ve a well

age, which is not found in the more m Leds of the lower part of the formation.

explainable entirely on lithologie more uniformly of a tuf are finer in grain,

assive This fact appears to be al grounds, the lower beds being aceous voleanic nature, while the upper beds and the voleanic materials are leavened with a

siliceous or argillaceous mixture, which makes them much better adapted to the development of cleavage.

A natural concomitant of this is the f

act that the lower beds form steep vertical cliffs (see Plate IX), while the upper beds break dow ments, and form no prominent to

While the whole formation ferent sulphides, it has yet to

n readily into small fragpographiec features, is very highly mineralized with dif-

e proved that any of its members are productive in valuable economic deposits.

Structure.—The present attitude of the

Red Mountain formation shows little change

from its original position, whie horizontal or nearly so. There is a fairly to the west as far

h must have been

uniform dip of about 20° as Bradshaw caiion, where the

tocks are faulted. When they appear ag:

gain in the west side of the fault, the dip has increased until the beds are nearly vertical, Beyond this,

they quickly die out, though the overlying rocks of the Aberdeen formation preserve this increased dip, far to the we stward, Microscopie Characters,—While the field proves the stratified nature of the brings out their fragmental orig

study of these rocks beds, the miecroseopie examination in. The breccias arn up of angular fragments of different kin embx dded in

een to be made Is of rocks of variou sizes, a very fine-grained ground-mass,

Fragments of glass are very common, which have

'en somewhat devitrified. Other fragaggregation of small quartz grains, indefinite hrown biotitie mass. Large erystals of plagioclase as some orthoclase feldspars, with y

common, as also clear glassy

ments are made up of an or an , as well

rague indefinite boundaries, are

quartz, with rounded or corroded borlight coloured pyroxene in eeecurring in small grains in

ders, There is mueh some sections,

Segregated areas, Frequently, brown

tranibove, come

d by c

well ssive , oO be eing beds th a otter t of (see

rag-

dif-

are

"tNe Teds of the Ree Mountain tormation.

M..

HEDLEY MINING DISTRICT: ORE DEPOSITS iy

Liotite of secondary origin has been developed out of the ground. mass, as a result of metamorphism, and some Silicifiecation has also taken place. Some samples are cut by many small stringers Containing feldspar. Pyrrhotite is everywhere very abundant, and especially in the small stringers. Some arsenopyrite is also present.

The very fine-grained reddish rocks which form such a large proportion of the rocks of this formation are more difficult of study on account of the smallness of the grains of which they are made up. These are made up of three constituents in approximately equal proportions—quartz, feldspar, and biotite. The grains are very small, generally angular in shape, and of a fairly uniform size throughout. The biotite is undoubtedly of secondary origin, and occurs in smal] crystals or incipient brownish grains, and is so abundant as to control the colour of the whole rock. The quartz and feldspar are difficult to separate from each other, on account of their microscopic size, but are in approximately equal proportion. The feldspars show no twinning, except an occasional Carlsbad twin. Iron ores are rare, and their iron contents may all have gone into the biotite. The rock has undoubtedly been altered by contact metamorphism, but it probably was originally a yery fine-grained volcanic ash. It shows no evidence of silicitication, except in the case of narrow cherty bands, alongside of which the rock is altered to a very fine-grained compact phase of the normal rock.

Coarser grained varietics of this reddish tutf contain, besides orthoclase and greenish hornblende, some glass fragments somewhat devitrified, all embedded in a very fine-grained ground-mass of g light brownish colour, containing much secondary biotite.

All these rocks give evidence of contact-metamorphism, and of some silicification, so that their original structure and composition is cbscured. In general, they vary between rhyolitie and andesitie tuifs.

Conditions of Deposition. —The rocks of the Red Mountain formation are thought to have been deposited under water, and there are several reasons for such a belief. In the first place, the separate beds of voleanic material are evenly and distinctly stratified, though they gradually wedge out toward the west, Again, they are often interstratified with true aqueous sediments, either siliceous or calcareous, and in the case of some of the breccias, the cementing material js a limestone. It would seem as if the whole formation represented

uo GLOLOGICAL SURVEY, CANADA

# long ani almost continuous perio! of voleanic activity, during Which veieanic ash and other materials were blown out from an active vent and deposited in Water, interrupting the normal order of "queous sedimentation, Where there were short periods of quiescence, the normal conditions of sedimentation held, and we find bands of quartzite, limestone or argillite, as indications of these periods, Under such conditions, we should expect to find all gradations between a pure tuff and a pure limestone or quartzite, and such is actually the case. Analogous deposits of this nature are being formed at the present day in the neighbourhood of voleanie islands, and these often abound in organic remains, as in the Solomon islands, the Tonga group, and Torres strait. The absence of organic remains in the Red Mountain voleanic formation does not disprove its deposition in water, Leeause the whole Cache Creck group of rocks is characteristically lacking in fossils.

Aberdeen Formation,

Distiibulion.—The Aberdeen forination is a distinctly sedimentary formation, embracing all the sedimentary rocks within the limits of the sheet above the upper portion of the Red Mountain formation. Where these volcanic rocks are not represented, this formation rests directly on top of the Kingston limestone. The boundary between the Red Mountain voleanic rocks and the Aberdeen formation is a fairly sharp line, but that between the Kingston limestone and the Aberdeen formation is not so easily identitied, on account of the transitional character of the two formations. The upper boundary of the formation is arbitrarily taken as the v estern boundary of the map, but as rocks of the same character as these extend for a considerable distance outside the map, the term Aberdeen formation is not as restricted as the two preceding formations, and is not intended to be used other than as a local name, and for convenience in describing them. The formation is not a distinct individualized unit, and, therefore, should not be used for purposes of wide correlation.

The Aberdeen formation is the highest portion of the ¢ ache Creek group, found inside the limits ot the sheet. It is very extensively developed in the northwestern part of the sheet, on both gives of Twentymile creek, but on account of the attitude in which the rocks

stand, the areal 'Tibution is not as large in proportion to its

during om an rder of scence, nds of eriods, ns beuch is ormed 3, the ins in sition acter-

imenimits ition. rests ween is a dary the contion not eniual-

vide

'cek vely of ae its

Hedley Mining District: Ore Deposits 67

thickness as some of the other formations. Its extent is also largely reduced by several intrusions of igneous rock,

Thickness.—It has been found quite impossible to obtain even an approximation to the thickness of the Aberdeen formation, both on account of the deformation which the rocks have suffered, and thi igneous rocks that have intruded them. The beds all stand at high angles, and'in the Aberdeen cafion there are exhibited some very close folds, so that in an east and west section across the strike there may be a repetition of strata. Although the formation is made up of beds of different composition, there is a sameness about the way in which these beds are interstratified with each other, which, in conjunction with a change of the same beds by contact metamorphism, makes it difficult to identify any single beds that might occur on either limb of a fold. It is certain that there are at least 3,000 feet of these rocks represented in the map, and if there is no repetition of beds, then twice that amount would not be too much to cover the whole formation.

Lithology.—The lithological characters of the Aberdeen formation have not been studied in great detail, but except that there is not such a relatively large proportion of siliceous beds, the main characteristics are very similar to those of the Redtop formation. In the lower portion of the formation there is a somewhat larger proportion of voleanie beds than is found higher up, due probably to the gradual diminution of the voleaniec activity, which was at its height during the deposition of the Red Mountain formation. In this lower portion we tind white quartzites interbanded with fine-grained black tuffs. Above this are interbanded limestones and tuffs, in bands of a few inches in thickness. Higher still we find the tuffs to have almost disappeared, and Liue limestones and white quartzites are interstratified together in bands which gradually increase jn thickness. In ascending the strata, these last mentioned conditions hold for many hundreds of feet in beds that dip at very high angles,

Nearly 3,000 feet up in the formation these conditions still hold, and in Aberdeen caiion, thin bands of blue limestone are interstratified with white quartzite, with the limestone preponderating. Occasionally, intercalated with them, are found thin bands of fine black tuffs or beds of volcanic breccia, generally only a few inches in thickness. The smaller of these bands are in many places seen to continue only for a short distance, and then to die out between the

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68 Geological Survey, Canada

layers of quartzite or limestone. These volcanic beds indieate that occasional outbursts of voleanie activity were still taking place, but that the effects were not far-reaching, and their limits are frequently recorded in the exposed beds of this formation. These tuffs weather to a rusty brown or red from the iron content, and they are very hard and siliceous, breaking with a conchoidal fracture. They contain a great dex! of mica in fine scales, which are well-developed along Cleavage or joint planes. The breccia beds contain only small fragments 1 inch or less in diameter, and indicate a greater distance from ihe source than the breecia beds of the Red Mountain formation. ,

With regard to the microscopic characters of these rocks, there is little to be said in addition to what has already been said of similar rocks in either the Redtop or Nickel Plate formation. On the whole, the quartzites and argillites show somewhat less_silicification by secondary actions than was evinced by the rocks of the Redtop formation. Except near eruptive igneous masses, where contact-metamorphism has been at work. the argillites are less siliceous, and the quartzites less cherty, and probably not so abundant. The voleanie rocks also are finer in grain.

The whole formation does not contain any large beds of quartzite, limestone, or other rocks, but is made up of alternating beds of different rocks, rarely more than a foot or two in thickness, and generally somewhat less than that. The characteristic appearance of the formation is well shown on the face of Stemwinder hill, overlooking the town of Hedley, where the rocks have a beautifully banded appearance, due to alternating shades of black and dark blue, to light green and white, the darker shades being produced by tufts, argillites, or limestones, while the cherty quartzites give the lighter.

Rapid and sudden changes in deposition is the characteristic feature of the rocks of the Aberdeen formation. Occasionally a change in the beds might indicate an oscillation of level, and a change from deep sea to nearly shore-line conditions; but often the change is from a true aqueous sediment to a volcanic rock, denoting an explosive outburst of voleanic activity, and the rapid deposition of voleanic materials from this source,

Structure.—The present attitude of the rocks of the Aberdeen formation shows a much greater tilting and deformation than any of the underlying formations. The whole formation Stands either in a

that

but tly ther ard in a long ragince ma-

ere ilar ole,

by naor- the nie

ite, if-

Hedley Mining District: Ore Deposits 69

vertical attitude, or is very highly inclined, and while there is little to indicate any large folds, so as to give a repetition of beds, many minor folds, closely compressed, are exposed in parts of Aberdeen cation. This is characteristic of all the upper portion of the Cache Creek group for several miles outside the map to the west. The compression which these rocks have undergone has not developed any well marked <laty cleavage, except in the argillaceous rocks in isolated portions outside the map, and here the cleavage developed is parallel to the bedding plane.

The topographie forms dependent on these rocks show nothing characteristic or prominent. In places, however, where they have been altered and silicitied by contact metamorphism, some prominent bluffs are formed.

While these rocks occasionally show some mineralization, no productive ore bodies have yet been discovered in them within the limits of the map. Outside and to the west, mining development shows some indications of silver ores occurring, and particularly where these rocks become much more argillaceous.

Correlation And Age Of The Cache Creek Group.

In the subjoined table, an attempt is made + compare the portion of the Cache Creek group of the Hedley area with the typical rocks of this age described by Dawson in the Kamloops map sheet. It must be borne in mind, however,, that the total thickness of 6,300 feet found in the Hedley district, does not ~-present the total thickness of Cache Creek rocks in this region. The base of the Cache Creek group in the Hedley sheet is not exposed, ag the lowest member is here seen to be a massive limestone, which is truncated by a batholithic intrusion of granodiorite. In the same Way, the uppermost beds, which are called in the table the Aberdeen formation, of which the minimum thickness is given as 3,000 feet, simply represent the amount of these beds that appears within the limits of the map. It is known that beds conformably overlying these extend for some 3 miles to the west, outside the sheet, when they are also truncated by a batholithic intrusion of granodiorite. The attitude of these beds outside the shect is, as a rule, about vertical. and it is very probable that a section across them would not represent their total thiexness, but something more, for the same beds may be many times repeated in closely folded anticlincs and synclines. It is impossible, therefore, to get even an approximation to the total thickness of

these rocks as originally represented in this portion of the Similka-

70 Geological Survey, Canada

meen district. The figures given in the table as the total thickness, then, merely represent the amount of Cache Creek rocks occurring within the limits of the Hedley map.

In placing these sedimentary rocks in the Cache Creek group, it must be confessed that the author is simply accepting Dr. Dawson's conclusion of over thirty years ago. In his report of explorations made in 1877, in referring to these rocks at Hedley, he says, !' They may be taken as representing the Cache Creek group, and are referred by analogy to the same age '—that is, the Carboniferous. He also makes mention of finding fossils in the rocks, a short distance above the mouth of Ashnola river, 8 miles below Hedley. These fossils were minute, branching tabulate corals, and the rocks in which they occur, precisely resemble lithologically those elsewhere found in association with quartzites, which hold Carboniferous fossils, The rocks to which he here refers lie about 6 miles to the southeast of the Hedley sheet, but are not found inside th's sheet. They probably represent, however, higher beds which are conformably above those of the Hedley sheet, and which at one time covered them, but have since been removed by erosion.

No new paleontological evidence to substantiate Dr. Dawson's conclusions has been obtained in the field work of the last two years. The only fossil found has been that of a badly crushed and quite indeterminable brachiopod in a bed of breccia. The correlation, then, of these rocks, is based entirely on lithological characters, tut the similarity to proven Cache Creek rocks no farther away than in the Kamloops map sheet, is so striking that correlation on these grounds alone must bear some weight.

The massive limestones of the upper part of Dawson's Kamloops section have no counterpart within the Hedley sheet, or even in the country immediately adjoining. His middle division, consisting essentially of volcanic materials with lesser quantities of limestones, argillites, and cherty quartzites, with a minimum tnickness of 2,000 feet, might well be represented by the two upper series of the Hedley column. There is a considerable difference in the relative thickness, but that can readily be accounted for—and indeed is to be expected—by local accumulation of voleanic material in certain sections. On the other hand, his description of the sedimentary beds intercalated between the volcanic materials, could be applied almost

Report of Progress, 1877-78, p. 87 B.

ots 2 eb a eat

an

HEDLEY MINING DISTRICT! ORE DEPOSITS el

without change t) those occurring in that part of the Hedley column. This portion of the column in both regions is characterized by a great preponderance of volcanic materials over the true sedimentary rocks.

Dawson's lowest division, which was originally called Lower Cache creek, consists of cherty quartzites, argillites, voleanic materials, and limestones, in about the relative order of importance in which these are nained. The corresponding beds in the Hedley map, while containing all the different kinds of sediments mentioned, with the exception of serpentine, perhaps vary somewhat in the relative importance of these components. Cherty quartzites are the most abundant members in the Kamloops section, whereas in theHedley section, limestones appear to preponderate in the upper parts; while lower down, the Redtop formation is characterized by a much greater development of quartzites, accompanied by siliceous argillites and voleanic materials—the latter locally. The minimum thickness of this part of the Kamloops section is given as 4,500 feet, whereas not more than 2,100 feet of the beds supposed to correspc . to these are found in the Hedley sheet. The disparity, however, is readily accounted for by the fact that the bottom of the Hedley section does not appear, having been truncated by eruptive rocks of a batholithic nature,

The data for correlation of these rocks is undoubtedly meagre. The use of parallel columns, however, serves to bring out the striking lithological resemblance between them, and suggests a similarity of cond' 'ons prevailing at the time of deposition of the beds. Both columns indicate many, and sometimes long continued periods of voleanic disturbance, and frequent changes in sedimentation on the sea floor. These features appear to be characteristic of Cache Creek tocks wherever found in central and southern British Columbia.

Rocks which have the lithologic characteristics of the Cache Creek group have been described by G. O. Smith, as occurring on the south side of the International Boundary line in the lower part of the Similkameen river. These are not now connected with the Hedley rocks, being separated by eruptive rocks, but they may represent contemporaneous sedimentation in Carboniferous times along 'the western side of the British Columbia Pre-Cambrian axis. :

"9

ts GEOLOGICAL SURVE Y, CANADA HEDLEY Seerjos, KaMLoops Srerioy, 3. Massive limestones with minor imtercalations of — vol anic rocks, quartzites, and argillites hee . 3,000 ft, 4, 'orme artz- : ' sto egy Form AO aLOATS 2. V oleanic materials, limestone, ites, limestones, siliceous ar : with some argillites and gillites and voleanie ma- sherty quartvites 2.000 ft META ere calyecat tay is O00 Te eherty quartz ees. : 3% Ded Vountain Formation os. sentially volcanic Materials, with some limestone and quartzite, . : 1,200 ft. +or 2. Micka Plate Formation : essen: 1, Cherty quartzites, voleanie tially limestone, with some materials, argillite, serpentine, ' quartzite bands 100 fr, and limestone 7, 00... - +. 4,500 ft.

1 Redtop Formation cherty quartzites, siliceous argillites, Volcanic materials, with some limestone bands.. 1,200 ft.

Base not seen,

Diorite Gabbro, Genera Statement,

This is a composite formation made up of a Variety of rocks ranging in mineralogical Composition between a quartz diorite at one end and a gabbro at the other. The quartz diorite, however, and the gabbro make up the bull: of the formazion; while the other varieties are relatively much less abundant, and are merely differentiates from one or the other, or transitional between them. These two main types are not exactly contemporaneous in age, but the difference between them js so slight that the older quartz diorite was not thoroughly solidified before the gabbro Was erupted through it, They are, consequently, very intimately associated with cach other, and for this reason, and on account of their evident consanguinity, they are classed together under one head. An attempt

Bias PD aL ike o8 5 tai

HEDLEY MINING DISTRICT! ORE DEPOS! ys 7

made in the colour scheme of the geological map to indivete the ery graphical distribution of these two main types, but the result js not very satisfactory, on account of the indefinite Nature of the contacts,

Distribu Tion,

The distribution of the rocks of the formation is indicated on the geological mip, and a glance at this will show that they lie mainly in the northwest quarter of the area, and on either side of the deep narrow cafion of Twentymile creek. They ove ir in three distinet stock-like masses, and in several intrusive. bodies of very irregular form, as well as in a grert number of apophyses from these larger bodies, The two large areas te the west are simple stocks, each due to a single intrusion of the diorite, while that on the east of Twentymile creek, on account of its being made up of separate intrusions of the two main types, is more correctly designated a composite stock. A smaller elongated body of gabbro, having some of the characteristics of a stock, as well as that of an injected body, makes up the prominent knob called Climax bluff, and forms the steep cliffs running northeastward from there.

All of these bodies are very irregular in outline, but the contacts with the older sedimentary rocks are generally well exposed, and can be accurately delineated wherever the topography will allow access to them. These contacts are often exposed deep enough to suggest a downward enlargement of each of the separate stocks, and as the distances by which they are separated from each other on the surface is not great, it is not unlikely that they would be found to unite below into one large stock; and that the portions now exposed are merely the unroofed portions of the upper surface. Further erosion would, therefore, tend to increase the areal extent of this formation.

In their intrusion through the older sedimentary formations. the rocks of the Hedley diorite-gabbro cut across the Strata, and send off 4 great number of apophyses, parallel to bedding planes of the sediments, as well as across them. The tilting of the sedimentary formations upwards toward the east, and subsequent erosion of the upturned edges, has exposed a large number of these apophyses on the eastern slope of Nickel Plate mountain. For the same reason, much fewer of these apophyses are seen on the western slope. Many of the apophyses from the diorite gabbro bodies were mapped, but many more occur which are not shown on the geological map. partly be-

eause they are small and irregular, and partly 01 a22711t of the

74 Geological Survey, Canada

impossibility of tracing them out in the very rugged portion of the region in which they eeceur

The distribution within the stocks themselves, of the Various types of rock which together make up the whole complex. is not easy to State very specitically, Quartz-diorite has the greatest areal distribution of all the ty pes represented, It forms the main central portions of the three Jarve stocks lying in the northwestern portion of the district, and is also found jn some of the larger irregular bodies in this section. It does not occur in the apophyses from these stocks, except to a very limited extent in the larger ones where they join the stocks,

Diorite is, as a rule, found to be a border phase of the quartz diorite, that js to say, it appears on the outer border ot the quartz diorite where tnis is in contact with the older rocks. It also makes up some of the smaller irregular projections from the stocks, such as that which runs off to the north by Aberdeen station. An elongated dike-like body which lies to the west of Bradshaw canon, near the top of Aberdeen ridge, is made up of a quartz mica diorite,

In apophyses whieh have been given off from the diorite stocks, and which are very abundant in the vicinity of these stocks, the rock is a diorite porphyry. This Phase of the complex is contined to the apophyses, and to only those apophyses which originated from the diorite portions of the stocks. These apophyses are most abundant in the region about the head of the gravity tram-line, but they are also found peripheral to all of the other stocks of diorite in the district.

Gabbro has not a wide areal distribution, and is almost entirely contined to the central portion of the district or the region centreing about Climex bluff. In the southernmost of the three stocks, namely, that into which the Horsetly gulch is cut, cores of gabbro: are surrounded bh. quartz diorite. Larger bodies of gabbro lie on the northern border of this stock. The most important area, however, is the elongated body which makes up Climax bluff and the steep cliffs running northeast from here for about 2,200 feet.

Porphyritic forms of the gabbro make up the apophyses which have been given off from the larger bodies, and these are most abundant on the Nickel Plate mountain about the Sunnyside mine, They are. however, not confined to the periphery of the plutonic gabbro masses, but are also sometimes found far away, in which cases they are always closely associated with the diorite phases of the complex.

the

ypes y to striions disthis 'ept oks, irtz irtz

kes

bh

oar Sanat

MEDLEY MINING DISTRICT! ORE DI POSsTpS rs

In a general way it may be said that gabbro and gabbro por only form about one-tenth of the total area covered the doorin gabbro complex Quartz diorite covers perhaps seven-ter th whi the remainder is oecupied by diorite, diorite porphyry, or transitions between diorite and gabbro.,

Lithological Characters,

Macroscopic.—The various kinds of rocks which together make iy) the diorite-gabbro complex, show considerable differences in appear: ances, as well as in mineralogical composition. When studied in tho field, it was found impracticable to differentiate sharply between the various types on account of the transitions between th m, and the lack of clearly defined contacts. There are, however, two main types which form the extremes in composition of this complex, and when these alone are compared, without the transitional forms, the contrast is marked; but when these transitional forms are included, a complete series is formed, which has no sharp "ne of division. At one end of this series is a quartz diorite, which 3ses easily into a normal looking diorite having no quartz at all. At he other end is a pale greenish white gabbro. The quartz diorite and the gabbro have the greatest areal distribution, while the intermodliate for.as are relatively less abundant.

The distinction between the two main types, that was made in the field, depends partly on colour and partly on mineralogical composition. The one is a medium (millimetre grained), light grey to dark coloured rock, generally normal looking quartz diorite, but with a variable proportion of the dark constituents in different areas. It contains two kinds of feldspar, black hornblende, and some quartz. In the field, and in a previous summary report, it was called a monzonite, but more detailed chemical and microscopic study proves that quartz diorite is a more appropriate name.

A basic phase of the quartz diorite is found, to a limited extent, in certain portions of the stocks, and more particularly on the outer borders. Such a rock shows a lack of quartz and a very marked increase in the pr >rtion of hornblende present, becoming thereby a typical hornblena. diorite. At times the hornblende becomes 30 abundant that it controls the colour of the rock, The accompanying plagioclase is correspondingly decreased, and the result is an almost

Ls sryeteaeiert!

6 "Lologicat Si Rvey, Canada

black pra; iteid reek, This eeeurs either in if} jy fined areas on the cuter border of the quartz diorite, op else jt forms streaks cr 'sehlieren' jy the quartz diorite.

The seeond main type of the complex je the gabbro, which oeey. res small areas in or alongsicdk the quartz dic rite. Itisa very pale greenish to almost ite roek, of equigranular texture and medium Courseness, Jt congiats essentially of Plagioclase, and very pale Freenish pyroxene (diallage), Its Seneral appearance js Suggestive of a much more acid composition than it actually proves to be. In the hand specimen, its chief points of difference from the quartz diorite lie in' its light colour, the absence of quartz and hornblende, and the presence of pyroxene, It frequently forms ill-detined contacts with the quartz diorite, as jf intrusive into it, sending off at the same time many narrow tongues into the quartz diorite. There 1s also a slight blending of the two rocks on these contacts, but only over a very narrow zone. In this zone are found minerals in association with each other, which aro peculiar to both types of rocks, It 'requeatly happens that on the contact of the quartz diorite with the older sedimentary rocks, not only is a normal hornblende diorite formed, but a rock which appears to be transitional between quartz ciorite and gabbro. This is a rock of lighter colour than the diorite, hut slightly darker than the gubbro, and the hand specimen show an abundance of light green Pyroxene, and some black hornblende,

Apophyses from the stocks, both from the diorite and gabbro bortions of them, have everywhere thrust themselves into the older "€cmentary rocks, and generally along the bedding planes as being the lines of least resistance. In these, while it is common to find a development of porphyritie Structure, this is not always an essential feature, In general, diorite Apophyses have ag Porphyritie structure developed in them by an enlargement of thy hornblende crystals, but on approaching the stocks this structure is lost and they take on the franitoid structure characteristi- of the stocks, The diorite apophyses are more basic than the quartz diorite in that they contain no quartz whatever. They correspond in mineral composition more nearly to the hornblende diorite phase of the stocks, than the quartz diorite,

As in the granitoid forms, there is a gradual transition from diorite to gabbro in the porphyritje forms. Tn the gabbro apophyses, porphyritic structure js nos so commonly seen; but the rock takes

H rd

on a ier grain, and the two main constituents—plagioclase

n the

'Ss OF

CCU. pale lium pale 'tive In artz OTlned t at ere nly ia- It ith ite tz te, un

ICEDLEY MINING DisTEte TP) ORK Db post. as

PS rOXer tre not se sharply differs ntiated, The transition ty 4 diorite porphyry js tharked by the appearance of large phenverys black hornblende embedded in the gabbro mass, These become rn nhundant us one foes toward ureas of typieal cdiorite porpu

until the gabbro characteristics are lost altogether,

The mica diorite of Bradshaw eaion is an isolated type, and not found in any but this one intrusion. In the hand specimen, j: has charactoristies Which appear to associate it with the Young: a special differentiate o: th iorite-gabbro magma. [t differ, from the quartz diorite in h

granodiorite, but it js more likely d avin quartz, bu' contains biotite as Wer. as hornblende, as an essentia!

constituent. These two minerals, with plagioclase, make up the eo.

ponents of the rock. Its structure is not eminently porphyritic, nor is it typical ranitoid, but while all the crystals are of Visible size, the three essential constituents tend to develop as phenocrysts ground-mass, whieh js made up of small grains of the erals,

Sune

Microscopic.—In discussing the petrography of thi divrite-gabbro

ury to avoid confusion or repetition, A six-fold division Suggests itself as the most Convenient and natural method of treatment. and all the important variations will b cluded in one or the other of these gix heads. These therefore: (1) quartz diorite; (2) diorite;

rocks, some method is necess

inwill be, (3) diorite porphy ries: (4) gabbro; (5) gabbro porphyries; (6) transition forms.

Quartz Divrite. ~This rock occurs only in platonie form in the stocks, and occasionally in the largest apophyses near the stocks, typical specimen, such as the one obtained from the base of Steminder hill, and the one whose chemical analysis is given farther on, ows tock of light to dark grey colour and medium grained ranitic texture. 'The dominant feldspar is plagioclase, with the Positic ©! andesine, and determined as Abss Anas. Zonary

is characteristic of it, showing tha' here is variation in

'on in different zones of the same crystal. The crystals sj. jy tendency to idiomorphic out''ne, and some exhibit a slight

and bending, which give a wavy extinction to the crystal. alteration of the plagioclase is not great, but small flakes of developed in it. Orthoclase is present as an essential con-

triable proportions. [t is less idiomorphie than the

2 hit

eer ae

fi. GEOLOGICAL SURVEY, CANADA

plagioclase, and slightly more d npose rim of orthoclase 'round a core of plagioclas: is oecusionally seen, Quartz is always Mnterstitial, and in clear glassy irregular grains it forms sometimes a8 much aa 15 per cent of the w hole rock, but usually less.

Green hornblende is the most bundant colou,-d constituent, and is always greatly in excess of the biotite, which is never more than "n accessory mineral. There is, however, a mutual relation between the two, and ve biotite generally occurs included in or adjacent to the hornblende, A tendenes to parallel arrangement of the hornblendes seen in the hand specimen is not evident in the thin section

The hornblende. js idiomorphie toward the othe istituents, and was the first of the essential constituents to ery- . out. It shows no evidence of being secondary in origin, nor an, dency to altera-

tion to other minerals, The flakes of brown mica, however, frequently exhibit a rim of secondary magnetite,

Of the accessory constituents, titanite is the most abundant, in characteristic wedge-shaped crystals. Calcite, which appears sparingly in the fresh rock, js apparently a primary constituent, and has been reckoned as such in calculating the norm of the rock. Other accessories are magnetite, arsenopyrite, epidote, and zireon.

A chemical analysis of the quartz diorite from the Stemwinder hill has heen made by M. F. Connor in the laboratory of the Mines Branch, Department of Mines. The following is the result :—

Oe riaaer ese peers eas he ae ee taUUe Tee. whine en oe Se RE OSH Se aa Sonu mrtiocniunr enrmricpe mn sn sae amar Be eet en eee Poncho ite Herat Gee Me ee Ped... 5:30 Mg 2-60 CaO. 7-20 Na,O. 3°15 K,O.. 1-98 H,04 . . 0-80 H,0- 0:10 CO,, ; : 0-18 TiO, ' 0-54 P,0,.. 0:12 MnO. 0-14 Sro.. , trace BaO.. 0-10

EY fENENE ISTHE ORE DEPOS|; rh By caleuiatic hey f thi according to t Inethod of C'poas ldding- 1 hit th (hiartz 10 és per Cert Orthoelane 11 ts Albite ie YO Sal Anorthite 08 Dhicpmmicte AM pee cent Hypersthene 13 S09 Hnenite oo "3b Magne tite 0 70 Ms etn Apatite. 031 Caleite 0 30 Sal ' : ee Clam 11 ticks aii Fem 1 if ' a , , Order 2 Nustrare H K,ONao l Ry 2 Ikali cahey CaQ 14 sang . C0) K,¢ ! Sulvrang 3 So ipeitanmac Na,O- 1 50

This rock, therefore, is harzose.

For the purpose of comparison

with the norm, the mode or a ual mineralogical composition was recalculated from the chemical analysis, and with the help of son microscopic determinations. The proportion of albite to anorthite in the plagioclase molecule was first determined from the thin section, and, from a large number of measurements, the ratio of Ab to An was found to be 55 to 45. The percentage of biotite was then determined by the Rosiwal method, and found to be 2-26. Enough K20 and other constituents were taken out to make up this percentage of a biotite with average chemical composition, and after allotting the proper number of molecules to make up the minerals known to oceur, the remainder was calculated as hornblende, with the excess of silica as quartz) The following result obtained by this method is fairly close to the average mineralogical composition, and is checked by the Rosiwal method :---

Quartz.. .. ° 48 Orthoclase, , 10-56 Plagioclase.. .. ,, 48:40 (andesine) Hornblende.. .. , 26°51 itenites iy cre : 0:98 MOGheHtS. co.cc .. 0°46 BDOUHOs eects 0°31 Calcite, . 0-30 'a ae

&0 Geological Survey, Canada

This mineral composition shows the rock to be a quartz diorite of a normal kind.

Diorite.—The quartz diorite rock is the most common and constant variety in the stocks, Variations, however, are noted in different portions of the same stock, and these variations depend on the relative proportions of the different constituents. Quartz is a very variable constituent, and to a certain extent the proportion of erthoclase varies with it. Occasionally the quartz disappears altogether, but some orthoclase always remains, and the rock becomes a normal diorite. Biotite is fairly constant, but merely as an accessory, the proportions of which seldom exceed] 2 per cent of the rock. Hornblende and plagioclase are always essential, the former varying in amount in different parts of the district and of the same stock.

The most basic form of the dioritie rocks is found in the extreme northwest portion of the district, at the western end of Aberdeen ridge. This, in the hand specimen, is a very dark, almost black rock. Under the microscope it shows no quartz whatever, and only a small amount of orthoclase. Plagioclase is abundantly present, but the amount of hornblende is very greatly increased over the amount present in the quartz diorite. The structure is distinetly poikilitic, with idiomorphic laths of plagioclase feldspar entirely enclosed in large crystals of dark green hornblende, the portions of which fill the spaces between the feldspars, but are all parts of one large crystal and extinguish together. Magnetite is more abundant than in the quartz diorite, and as before, often occurs as a secondary rim about the small flakes of biotite that are present. Some arsenopyrite is present az an accessory constituent.

Diorite Porphyries.—Apophyses from the dioritie portions of these stocks have penetrated widely the older sedimantary rocks. These are more of the nature of sheets injected into the bedding planes of the strata, but cross-cutting apophyses are also common. As might be expected from the position of the stocks, and the way in which the strata dip into them from the east, the greatest number of these apophyses are on the east of the stocks. and on the eastern and southern slopes of Nickel Plate mountain. From their iron content these apophyses always weather to a dark red colour, and often form prominent ridges. Different dikes of this rock vary considerably in size, and are found up to 50 feet in thickness; but individual

dikes are remarkably uniform in size. and are very persistent. In

Pts. tiered

PO Np Sou Maat pos 7"

In Alwil

Steg RFPER efor ea RR RR

Hedley Mining District: Ore Deposits 8]

typical examples of these, the structure is porphyritic except where they approach the parent stock, and here the structure becomes gradually more granitic. The phenocrysts are invariably long black hornblendes and plagioclase feldspars. These feldspars are basic andesine in composition and frequently show zonal structure. They are always idiomorphiec, and of variable size, passing gradually into the feldspars of the ground-mass. They show some alteration due to decomposition, and are irregularly fractured, anc in the Vicinity of the granodiorite contact there is metamorphism, due to this contact. The hornblendes are long and lath shaped, and show no transition in size to the hornblendes of the ground-mass, They are generally fresh, but occasionally show some alteration to chlorite. The ground-mass is hoto-crystalline, and made up of small laths of feldspar and hornblende, and shreds of brown mica. Some orthoclase is present in the ground-mass. Accessory minerals are titanite, arsenopyrite, pyrrhotite, and some quartz, the sulphides being usually quite abundant. The titanite is in small grains or wedge-shaped crystals associated with the hornblende. Pyroxene is entirely wanting. From this undoubted genetic connexion and mineralogical similarity to the diorite of the stocks, these apophyses are properly termed diorite porphyries,

An isolated phase of the dike forms of the diorite is a porphyritie mica diorite found cutting sedimentary rocks to the west of Bradshaw cajion. It cannot be connected directly with the diorite of the stocks, but it has characteristics which associate it with the diorite. In the thin section, it shows three essential constituents—plagioclase, hornblende, and biotite. The plagioclase is andesine, occurring in large crystals with rounded outlines, frequently strained and sometimes broken. Biotite is in brown crystals also strained and bent, while the hornblende is green in colour and in large crystals less abundant than the biotite. The structure is slightly porphyritic, with a ground-mass composed of grains of Plagioclase, orthoclase, biotite, and hornblende, enclosing the three larger constituents. The ground-mass appears to have suffered considerable deformation, and by the crushing and granulation of its constituents during intrusion, 8 protocle stie structure has been developed.

Gabbro.—The later phase of the diorite-gabbro composite stocks is a gabbro which is thought to be merely a product of the

same magma as the diorite, but erupted after differentiation has 9185-—6

&2 Geological Survey, Canada

taken place. The rock in the hand specimen is alinost white in colour, and of .:ranitoid texture. Typical examples of this rock are obtained from the western face of Climax bluff, and from the upper porticn of the composite stock to the north of the KXingston mineral claim. From the latter place, samples were taken for petrographic study, as well as for chemical analysis.

The thin section of the gabbio shows the rock to be made up of cnly two essential constituents—plagioclase feldspar, and pyroxene. The plagioclase has been determined as labradorite of the composition Ab,An,, and forms about 56 per cent of the whole rock. It shows a slight zonary banding, with a more acid feldspar on the outer border. The crystals are well developed, and show a peculiar irregular fracturing. They also exhibit a slight tendency to parallel arrangement of their longer axes. They are slightly turbid, indicating a certain degree of alteration. Their whole structure is hypidiomorphic.

The pyroxene is almost colourless, or has a pale greenish colour, und forms about 39 per cent of the whole rock. It appears in large tabular crystals of typical augitic habit, giving extinction angles in the neighbourhood of 45°. The crystals all have good prismatic cleavage, with occasionally a parting dividing the angle of cleavage. They are always fresh, and show no decomposition or alteration to other minerals. In spite of its strongly augitic habit, its chemical composition, as determined from the chemical analysis of the rock, is very similar to the chemical composition of a diallage described by Dana as occurring in gabbro at Ehrsberg.!

The Hedley pyroxene, as shown by the rock analysis, is marked by a total absence of F,0, and a fairly high per cent of A1,0,, and from this composition it can only be called a diallage, but one 4 augitie habit. The chemical composition as computed. is as follows :—

SIO pseu elas r wnat Pe an eal ea eae aan CRM WE BD SRR LON Pee ore te ress eee gah senate Meieue buat oalorarg te rece IGA Be BOO iis ose se eed von eiasl ee ae Vtow aa ahs ee OR 30 Gpke a nue et nto itil We rchs WA wei eesa iene creer Cares ea BEE eas NOD ula sa Saleh oe ee eee 21-09

Of the other constituents of the gabbro, orthoclase is sparingly present, and quartz is absent. Titanite is very abundant as an acces-

*Dana's Svstem of Mineralogy, p. 360, No. 55.

ns

'4 fa HEDLFY MINING DISTRICT: ORE DEPOSITS 83 in ts sory in small wedge-shaped crystals and grains. Apatite forms large are ie thick crystals, and some primary calcite is found in some sections. per The following chemical analysis of the gabbro was made by M. ral F. Connor in the laboratory of the Mines Branck of the Department hic of Mines :— ' SiO, 51-08 of Fa Bho 19-77 be Fe,0, trace ne. i FeO. 3-60 ; k MgO 4:57 S1- f CaO. 16-03 Na,O 2-56 It K,O O28 the H,0+ 065 . H.O 015 lar co, mai 0-99 TiO. 0-45 lel P.O 0-14 at- MnO ss SS (OS : BYO pos oe, Recents A ete get ede ee es 10- BOO: pescinars tome eee (ie OOM aA Me mG at Pe ur, : rge Calculation of the norm, according to the method of Cross, Iddin ings, Washington, and Pirsson, gives the following percentages of the tic different constituents :— ane Quartz. 0°06 per cent. . Orthoclase.. 1°67 Me oasis Pere ey, Albite 2148 0, 117) 64°91 Salic. al Anorthite. Al20: Gs. aes. k Divpside 28°37 ' bid Hypersthene 3°7: " me tate ed Apatite 0°31 " t+ see. 33'86 Femic, {Imenite ... 0°76 " a hanaeh Calcite 0°70 ' ed Sal. 1°91 ae Sa CMMBBE RS Wc eeet ete flaunt ey eee ene Dosalane. Of Fem. J a: se rates ne QL. a 'e ; as F. Ord ety Ore ne ducan ay rats oe cyt ves Pata Germanare, K,0+Na,O 1 a wt oo ae Rang $8... oo oo cccccesceeclccces, Devaleie. Gad 5-99 Rang 4 De-alcic KO 1 aT Na,O 9147 SHO-PANG Bae ere ee ee vseese. Presodic,

According to the above classification, the rock is, therefore, a ly : hessose.

ee Owing to the simplicity of its mineral composition as s. i under : E , ; ; Rees ; the microscope, a recalculation of the mode or actual mineralogiva!

; composition is a simple matter. after tho pr of -hite to

84 Geological Survey, Canada

anorthite in the plagioclase has been accurately determined. This proportion is found by a number of measurements ty be 40 to bu. All the Na,O is then allotted to the albite. and a suttcient amount of CaO to the anorthite, to make the above proportion, After taking out the apatite, titanite, and calcite, all of whieh are known t: occur in the rock, the remainder is caleulated as pyroxene, the proportion of RO to SiO, being almost exactly 1 to 1. The actual

mineral composition as computed by this method, is as follows:—

Orthoclase 5 4, 54.736 °° I CAL CT CTE C Prone Ap Siaeamrne saeatall PL cig Oe ae wel DETER aCe aaa AA ata cr pitk he caw niuen Aen eS Shab! EL DLC) aera SOR Sea Mee on aie oe pare mins ROMY oes : dt Pitanitecctars: css $e tne len aw adhe ee alae ) 8 LOD TUT c Sie ay Steyr ae aA ee eee Meta Penlas Gn ong ive 7h

Plagioclase and pyroxene together make up about 96 per cent of the whole rock. Though of such simple mineral Compdsitinir, mo rocks of exactly similar chemical composition could be foil iu Washington's compilation of superior analyses. Both the high percentage of CaO and the absence of Fe,O, make it rather abnormal. The nearest approach in composition to it is a gabbro described by H. W. Fairbanks, from Point Sal, Santa Barbara county, California.* G. O. Smith has also described a gabbro from Beverle:

creek, Kittitas county, Washington, which is somewhat similar in composition.2 The analyses of each of these rocks, however, show a lower percentage of SiO, and CaO, but a higher percentage of MgO and total iron. The megaseopie characters of the Beverley Creek rock are also somewhat similar to the Hedley gabbro.4| Smith describes it as a rock of light g-ey to greenish or purplish colour, and composed of basic labradorite and diallage, with some hornblend> and magnetite.

Gabbro Porphyries.—The dike forms of the gabbro are, like those of the diorite, apophyses from the parent st- and they appear both as sheets in the bedding planes of the se rents and as erosscutting bodies. In distribution they are less abundant than the diorite rocks, and are more restricted in area. They are found most abundantly on the Nickel Plate and Sunnyside mines. where some

*U.S.G.S. Prof. paper 14.

Bull. Dept. of Geol., Univ. Cal., p. 50, 1896. °U.S.G.S., folio No. 106, p. 6.

"Thid

EPLEY MINING DISTRICT! ORE DEPOs! Ts Ss)

attain a thickness of 100 feet or more. They are always clos ly associated with the ore deposits, and are, therefore, of great economic importance,

Mineralogically, the gabbro apophyses are identical with the rock ct the stocks, with often the development of a porphyritie structure. In the hand specimen the rock is white, and often tine-grained, and from its hardness forms bold outeropping ridges between the bands of sedimentary rocks. The thin section shows generally a porphyritic structure, with phenocrysts of feldspar and pyroxene in a finegrained but erystalline ground-mass. The feldspars are labradorite with the characteristic zonal structure. The pyroxene is white or very pale greenish, and is in broad tabular idio.n yephic crystals identical with the pyroxene of the stocks, which is a diallage. These pyroxenes are often crushed and fractured, and are at times, in the neighbourhood of the ore bodies, entirely replaced by potash-feldspar, or by calcite. In the case of replacement by feldspar, the resultant mineral is made up of a number of small grains which toeither form. a pseudomorph after the pyroxene, The gvround-mas is fine-grained, and made up of small crystals of plagioclase and grains of light coloured pyroxene, with some titanite, and much sulphide mineral, which is generally arsenopyrite. Most of ihe thin sections studied show a notable amount of metamorphism, particularly of the pyroxene. Some silicitication is also evident near the ore

bodies, but no primary quartz is ever seen,

ition Forms,—Transitions between 4 diorite and a gabbro, both in the plutenie and porphyritie forms, were noticed in the tield. and iicroseopie study confirms the conclusions there formed. In the plutonic forms, this transition was noticed particularly on thi cuter border of ihe diorite stocks, where differentiation by basitication had taken place. Thin sections of these show a slightly finer grain, with the femic materials more highly developed than the sale. The feldspar is labradorite in long lath-shaped erystals, idiomorphie toward the other salic minerals. Orthoclase is present in a small and variable proportion. Quartz varies with the orthoclase. and may be present or not. If present it is in small irre gular crystals filling interstices between the other minerals. Among the femice minerals, horniJende is the more abundant, but occasionally pyroxene forms the larger proportion. When in the ascendan., hornblende forms large elongated crystals, while the pyroxene is in small tabular

86 Geological Survey, Canada

grains. When the pyroxene is more abundant, it oceurs in broad tabular crystals of a white or very pale green colour, without sensible pleochroism, Biotite is generally present as an accessory, and When most abundant is found moulded onto the hornblende. When pyroxene increases the biotite decreases, like the quartz, The usual accessory minerals are present here also, and there is much sulphide mineral, either pyrite or arsenopyrite.

In the porphyritic forms, transition types intermediate between gabbro and diorite are occasionally found. Those types which are more nearly related to the gabbro show a ground-mass identical with that of the typical gabbro porphyry; but besides the labradorite and pyroxene phenocrysts, there are large elongated phenocrysts of black hornblende, seattered sparingly through the rock, generally inches apart from each other. As the type approaches the composition of the diorite porphyry, the hornblendes increase in quantity, and thin sections of these show phenoerysts of both hornblende and pyroxene, with the labradorite embedded in a fine-grained ground-mass, composed of feldspar and pyroxene grains. Quartz as a primary constituent is entirely wanting in all the sections. Arsenopyrite is often

very abundant as an accessory constituent in well formed crystals.

Metamorphism.—From external agencies, the rocks of the dioritegabbro formation have suffered little metamorphism. The effects produced on its internal structure by regional orogenic movements have not been very markedl, and are disecrissed in a later section. The contact metamorphism which has been induced in it by the intrusion of the grancdiorite through it is also very light, and not to be compared with that which this rock had induced in the stratitied rocks. A good contact between the granodiorite and the diorite ean be seen on the Metropolitan mineral claim on the eastern slope of the valley of Twentymile creek. Here the contact is a sharp line, and what metamorphism the.e is in the diorite is very slight, and not apparent to the unaided eye.

The contact metamorvhism which it has sutfere:

lin its own body by reason of intrusion through older rocks has :

already been referred to, and need only be brietly mentioned here. The effect on the diorite

has been a slight basifieation along the contact. and the formation

of pyroxene in addition to hornblende, with the complete elimination of quartz, 'The presence also of some lime silicate at the immediate

contact might indicate the absorption of sone material from the

Nene OS TIENT eR em nR.

(hOLEY MINING DISTRICT! ORE DEPOSITS s7

sedimentary rocks. In the case of the gabbro, no such basitioution Was noticed, but a very evident. silicitication on the contac: of quartzite by the absorption of some of the quartz is a phenomenon Very noticeuble in thin sections of the contact rock.

The most marked metamorphism is seen in the gabbro apophis where the have been intruded into the sedimentary rocks, and where ore bodies have been formed. This metamorphism takes the form of a replacer at of the pyroxene of the gabbro by secondary feldspar and by calcite. The secondary feldspar is here an unstriated potash feldspar, always clear and fresh. It occurs in small grains, replacing the pyroxene crystals by attacking them from the outer border and projecting inward. In the early stages of this process there is often seen a core of pyroxene surrounded by a ring of small feldspar crystals, all pointing inward toward the centre of the pyroxene. When this process has been completed the result is a pseudomorph after pyroxene composed of an aggregation of feldspar grains. In other instances the secondary feldspar develops irregu- Jnrly through the pyroxene crystals, so that a sort of poikilitie strueture is developed. The same feldspar fills fissures which traverse the gabbro. These are always minute, and are not apparent except under the microscope.

In the same manner as the feldspar replaceinent, calcite atso replaces pyroxene and fills sp all fissures in the xabbro. The source of the calcite is appavent, and is undoubtedly in the sedimentary rocks into which the gabbro has been intruded. The presence of the alkali feldspar, however, is not so easy of explanation, but it is probably connected! with certain phenomena following the intrusion of the gaubro apophyses.

Structural Relations.

Infernal.—The internal structure, so far as it can be referred to differentiation, or the relation of one type to the other, has been partly discussed under a previous heading, but it will be as well to state all the evidence here, even at the risk of repetition.

As previously stated, there are two main types of rocks in the complex—a quartz diorite and a gabbro. The fe mer composes the bulk of the complex, and occupies the main central portions of all three stocks, while the latter is in smaller yolume, eit or in the same stock with the quartz diorite, or alone. Where the two occur in the

GEOLOGICAL Bt RVEY, CANADA

Same stock, and are in contact with each other, a great number of

harrow tongues of gabbro are found projecting into the quartz

diorite, and ramifying through it. The contacts, however, are not

sharp, but show a decided biending of one rock with the other, giviag

Just such an etfect as might be expected if the gabbro were intruded

into the quartz diorite before the latter had thoroughly solidified.

Such 'acts indicate an intrusion of the gabbro, slightly later

than the quartz diorite.

Within its own mass the quartz diorite shows considerable variation in mineral composition in different parts of the same stock, This is not s much a difference of kind as a difference in the relative proportions of the same minerals, Such differences never result in the formation of a more acid rock than the quartz dic site,

rut they always tend to produce

a rock slightly more basic, an yp. Toaching the composition of the sabbro. Such differences are

most marked, also, on the older

contacts of the quartz diorite, and in the apophyses which have originated from the stocks, While the con-

tacts of the quartz dicrite show a thorough transition to galbro

over a distance of an inch, or

a few inches, there is also a longer, but just as complete a transition throug:

. their apophyses, which Zives the same result,

Starting with the quartz diorite of the the east side of Twentymile creek, we find that. southern border of this body, one of the apophyses, the

stock on on approaching the quartz diminishes in quantity, Entering quartz disappears altogether, and the rock

has become a diorite porphyry. Numbers of these porphyry dikes -an

be found crossing the electric and eravity tram-lines near the upper cre bin, and many of them can

traced directly by their outcrops into the parent stock.

Passing next along the electric tram-line northward from the head of the gravity tram-line to the Nickel Plate mine, a complete transition dikes crossed from diorite porphyry ition is not continuous by one dike

can be marked in the different to gabbro porphyry. This transalone, but is apparent in passing from one dike to the other. The change js effected by a gradual disappearance of the hornblende of the diorite porp' ry, and the appearance of pyroxene in its place, both in the Phenoerysts and in the ground-mass, until the rocks of the Nickel Plate mine have the mineral composition of the gabbro without any hornblende whatever. These last rocks are apophyses from the stock of gabby

o which forms Climax bluff.

Zz

Trpley Minen Strict Orf

DEPOs} is Sa)

The gabbro itself, where it

ppears as cores in the quartz or as 'isolated bodies, js gen

lly uniform throughout, ani no tendency to differentiate to more basic to be itself the final femie prov rites cabbro magma, of which the qu rte diorite is the sale pole. That the progress of differentiation wos from

the fact that the gabbro is intrusive into the quartz diorite, and js, therefore, a later rock

. Again, in the dike forms of these rocks, the

rite, "hows forms, It appears rather 'et of differentiation of the di.

acid to basie, is shown by

gabbro porphyrics sre not always confined to the borders of the cabbro stocks, te. fou ong distances away, In such cases, however, t wave elo ssociated with diorite ThASs8es, In contrast to 1 ire the geobro, the dike forms of the diorite are alwa Yo as soelate th the mas.ive forms or stocks of this rev ver spear or the periphery of the gabbro as differentiati: f tl 'bro. ~The conclusion one might draw is that the sa cater differentiation product of the original magma ¢ 7 s¢ dier

It is very es that he two mai; es of this complex arc closely related, rm: aly it wieal combosition, but in mode

of origin. The relation the other app2ar to show

tee Magra, and one probably

eel The two reeks, Also, that after

that they wer th der intermediate in © ompositii

the processes ef rm egma chamber had advanced to such a stage that th sore or less stratified into a quartz dior f ow, the top layer cooled some what more dly ai lif Before complete sulidifica-

tion, however the low: igtua was forced up through the

pasty crust of quartz

e the conditions as we now have them.

The internal structs rite-gabbro complex, so far as

it is dependent on exte ies such as mountain building, is an easier study, and of a ss theoretical nature. The apophyses of these rocks generally lie parallel to t sedimentary rocks into which they ha: show folding and crumpling. the igne

ture. Either the igneous 1

bedding planes of the old been thrust, and where these

rocks show a similar strueks were thrust into the sediments when they were lying in a horizontal undisturbed position, and afterwards elevated and folded together; or it is possible that the sedimentary rocks were first folded. and the igneous rocks were

afterwards thrust

90 Geological Survey, Canada

inte them, following alone the bedding planes of the folded sedimen tary rocks as the lines of least resistance, The evidenee at hand is not sufficient te solve the problem, but it is more than likely that the folding may have had a geuetic connexion with the igneous intrusion, and that the two events are not separated by any great length of time.

It is ortain that these rocks have been subjeeted to all of the faulting that is now evident in the rocks of this distriet. No faulting appears to have affected the Carboniferous sediments without affecting the diorite-gabbro rocks, but much of this has not affected the later granodiorite, Fissuring is also apparent in the ttumber of small stringers of feldspar that traverse these rocks everywhere. These are always small, and are oceasionally mineralized with arsenopyrite, but the mineralization is never enough to form ore bodies of even doubtful value. Evidence of deformation is also to be obtained from a study of the thin sections. In these, a slight straining and bending of the feldspar erystals, accompanied by granulation of the ground-mass, is frequently seen. No schistosity, however, has been developed, though there is occasionally a tendeney toward it in the parallel arrangement of some of the hornblendes. Some shearing is seen, and altogether these rocks have undoubtedly passed through

some rather severe orogenic disturbances.

External —(a) Relation to Older Formations.—vidence illustrative of the relation ef the dicrite-gabbro complex to other formations is never lacking, and contacts are very common. Partieularly appurenc is its relation to the Cae Creek sediments. These contacts show the intrusive relation of tue complex, and the way in which dozens of sheets and dikes from it have penetrated into and across their bedding planes. At the same time the metamorphism that has been induced in these sediments is extreme, and they show striking evidence of alteration pt and near the contacts. The limestones have been most altered, and by the expulsion of the CO, and the substitution of SiO, the carbonates have been altered to silicates, with the formation of sueh minerals as garnet, epidot, diopside, tremolite, wollastonite, and axinite. The impure limestones show much more contact metamorphism than the pure massive forms. The contact in the massive forms is rarely a clean-cut line. and there is evidence, hy the inclusion of some of these lime silieates in

the diorite-gabbro near the contact, that there has been some assimi-

HEDLEY MINING DISTRIOT: ORE DRPOsETSs He lation of the sedimentary rocks. The eontaet Metamorphisey in the sediments, besides showing alteration to lime silieatas, sory

often takes the form of dense grey siliceous masses of irregular out line and variable size.

Often, also, the silicitication has contined itself to certain bands, and in these the resultant rock is fine grained and cherty, and com posed largely of chaleedonie silica.

Accompanying the formation of lime silicates in the contact metamorphic zone, there has been at the same time an introduction vf sulphides from the diorite-gabbro complex. These sulphides ary arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, and pyrite, and their intergrowth with each other, and with the lime silieates, shows an almost contemporaneous formation. Contrary to what might be expected, the gabbro has apparently been more effective in indueing contact metamorphism, and in mineralization, than the diorite

While the gabbro shows, as a rule, much the same kind oo indefinite contact with the sediments as ths quarts diovite, it also forms, in some places, a brecciated eontaet. In such cases there is & narrow zone of breeciation a few feet wide, where highly alt: red fraginents of the sedimentary rocks are cemented together by igneets material, soft, friable, easily weathered, and with a ropy structure. These contacts suguest locally a different mode of intrusion to the others.

(b) Relation to Younger Formations. —A well-known contact between quartz diorite and granodiorite appears on the Metropolitan mineral claim, It is noticed here that the granoliorite sends off apophyses into the quartz diorite, and often holds fragments o1 the latter in its own body. Again, many contacts show the granodiorite truncating sheets of diorite porphyry, which are interbedded with the sedimentary rocks. In all cases, hovever, the metamorphism induced in the quartz diorite is relatively insignificant.

No contacts of gabbro with the granodiorite are ever seen, but an example of a small roof pendant of sedimentary rocks, in which is a dike of gabbro, resting on and completely surrounded granodiorite, is sufficient to establish the relative age of these two rocks, The diorite-gabbro andesite rocks are also known to be ent by lamprophyre, keratop! vre, and rhyolite di]

Mode Of Origin.

The nature of the intrusion of the diorite-zabbro complex j

shown in many exposures of its eontacts with the Ider

ma.

92 Geological Survey, Canada

sedimentary rocks. These exposures show by the size, evenness of train, and mineral association of the component crystals of the gabbro diorite. that it solidified under deep-seated conditions. The physical relations to the older rocks show that the magma did not make room for itself by thrusting aside the sediments, tor they do not now show any evidence of dislocation trom these intrusions, Contacts which show the diorite-gabbro rocks cutting directly across the bedding planes of the sediments, though they have induced much metamorphism in the sediments, indicate that the uniformity of the dip of the strata has not been disturbed on their edges. The action pf intrusion, therefore, appears to have been quiet and gradual, and similar te that recorded on the contacts of many batholithic masses. The areal extent of the diorite-gabbro rocks in the district is not great in any one of the three main masses exposed, so that they are properly designated by the term stocks. The horizontal distance, however, which Separates these masses, in all cases is so small that we might be justified in presuming that they would all be united into one main body at no great distance below the surface.

The mode of origin of the galbro portion of the stocks is not sc clearly expressed in its contacts as that of th- quartz diorite. Where it cuts sedimentary rocks, it is true it exhibits a vertical or highly inclined contact with au even more indefinite contaet line than the quartz diorite forms: but it frequently also shows a brecciated contact zone for short distances, as if it had here forced a way for itself through the overlying sediments. A good exposure of its contact with the sedimentary rocks at Climax bluff shows the characteristic vague contact zone. Here the intrude] rock is Al guartzite. The gabbro itself is an almost white rock. and in passing over the contact, it is impossible to sav. within several vards, where the igneous rock begins, or the sedimentary ends. The two appear to merge into each other. The thin section too, brings out this blending of the two rocks by a mingling of constituents, for while the normal gabbro contains no quartz whatever, it: is seen here to carry much quartz in a sample which was taken a short, but undetermined distance away fron the contact, in what was thought megascopically to be normal gabbro. In the intrusion of this rock, therefore. it looks as if there might have been forcible injection of molten rock along a passage which it made or enlarged

Wedley Mining District! Ore Deposits

for itself, and this was aeeo npanield by 30mea assimilatio ; intruded rocks.

The contacts with the quartz diorite do not throw much light the method of intrusion of the gabbro. The contact has ; road been described as a transition one, with mumbers of small apophyses from the gabbro, projecting into the quartz diorite. and blending with it, all tending to show that the quartz diorite was still in an unsolidified pasty condition at the time of the gabbro intrusion. In this case, the exposures now seen must then, have been at considerable depth, and the foreible injection of the gabbro into the quartz diorit would leave no evidenee of such an injection on the quartz diorite, for this rock would readily adjust itself to the position into which it was thrust. and there solidify later.

Age And Correlation,

The question of the age of the diorite-gabbro complex is one which is attended with much difficulty and obscurity. Evidence has been cited for the belief that the quartz diorite and gabbro are closely connected in origin, and in time of irruption, so that in attempting to tix their age they may be considered together.

We know the relative age of these rocks, namely, that they are younger than the Cache Creek sediments, and older than the granodiorite, but the date of the latter intrusion is also uncertain. there are no later sediments to which it ean be referred. There remains, therefore, merely the structural features by which to assign the age.

Orogenice crushing, and consequent metamorphism, does not seem to have affected these rocks very largely, and certainly not to the extent of developing any schistose structure, or much shearing. That they have undergone some such movement, however, is shown by the fracturing and granulation exhibited in the thin sections, and by the straining and bending of some of the erystals. Moezascopieally, too, fracturing is seen in the small narrow fissures with which the rock is traversed. Faulting, also, on a large seale has taker place since the intrusion of these rocks. There are two pariods recorded in the history of rocks, later than Carboniferous. in this part of British Columbia, when intense orogenie disturbances took place'—one about the close of the Jurassic, when the Cache Creek

sediments were uplifted and folded, and another at the close of the

Ne A ALY Wit Gre ce EAN VoLoelT ine Cogateh

94 Geological Survey, Canada

Laramie, when the Cretaceous rocks of the upper Siimilkameen river were crushed and folded. It is not likely that these rocks could have passed through both of these periods without showing more evidence of it, but it is tolerably certain that they have been affected by one such period of disturbance, and that presumably the latter ene, namely the nost-Laramie disturbance, It is, therefore, inferred that the time of irruption of these rocks should he placed in a time somewhere between the close of the Jurassic and the end of the Laramie. They are consequently called Mesozoic, without attempting to further restrict their age.

Granodiorite. Distribu Tion,

The rocks described under this head. and indicated on the ap by one colour, are generally uniform throughout, and show little variation in petrographic characters. The portion appearing on the map forms only a small fraction of a large batholith which extends outside the area to the east and south, and many miles to the west. Within the limits of the Hedley district these rocks attain their greatest exposed development in the southern half of the sheet, and if they were not covered by the recent stream deposits of the Similkameen river and Twentymile creek, would be found to have a still wider distribution than that shown.

This is the latest consolidated formation in tha district, and cuts all the others. From its mode of origin, and the way in which it is seen to underlie the sedimentary rocks on the slop of the Similkameen valley, it i: 'o be expected that its underground development will be much greater than that shown on tho surface, and it may be found to form the floor on which most of the other rocks of the district rest.

In the southwest portion of the distri >t, it occupies the lower portion of the Similkameen valley, and underlies all the other formations. In the southeast portion its contact, rising suddenly from the lower portion of the valley, cuts directly across the overlying sediments, and passes outside the district to the east at about the 4,500 ft. contour line.

Genetically connected with the main batholith of granodiorite is a dike-like body of similar rock extending from Eighteenmile creek in a direction N 30° W across the shoulder of the mountain, and down to the bend in Twentymile creek, about a mile above the

Hedley Mining District: Ore Deposits 95

town. This body is nearly 2 miles lon, has an average width of about 450 feet. and is almost perfectly straight. It apparently follows one of the main lines of weakness in the district, and one that coincides with the trend of Twentymile creek in that portion aleve the first bend.

Lithology.

Macro:copic—The normal rock of the granodiorite is light coloured and medium grained (millimetre grained) in texture. It is made up of two kinds of feldspar and quartz, with hornblende, or biotite, or both. The dike-like body appears uniformly to carry biotite in excess of the hornblende, but in the main body the proportion is more equal, with generally hornblende predominating. It shows very little surface Weathering, and is generally fairly fresh

on the outerop. On this account, it breaks along its joint planes

into huge blocks, and forms talus slopes of these blocks, unlike the

slopes of any other formation. Where it does weather down it forms a coarse pinkish sand, easily distinguished from the soil overlying limeston. or diorite. It contains many rounded or oval-shaped basic segregations, and is frequently traversed by small veinlets of feldspar or quartz.

Microscopie.—Unlike the diorite-gabbro formation, the granodiorite is fairly uniform in texture and composition throughout all parts of its body, except the immediate contact phase. single specimen of a fresh rock selected from the main body would. therefore, be fairly representative of the whole formation. Under the microscope, such a section shows a very fresh rock which has undergone little decomposition or deformation. It is made up of plagioclase. orthoclase, quartz, hornblende, and biotite as the essential constituents.

Plagioclase is the most abundant eon tuent, and is an oligoclase in composition. It is usually twinned polysynthetically, after the albite law, and is generally idiomorphie toward the orthoclase. The crystals are large, broad, and fresh, and show very little alteration. Zonary banding is very characteristic of the plagioclase, and individuals with a basie centre become slightly more acid toward the outer border, Orthoclase is much less abundant, and is generally slightly turbid from decomposition and the formation of small

96 Geological Survey, Canada

flakes of mica throughout the erystals, There is a frequent intergrowth of the orthoclase with quartz, resulting in micrographie structure,

Quartz is less abundant than ihe feldspars. It always has irregular outlines, and occurs in interstices between the other constituents, being the last to form. Jt is always clear, fresh, and glassy, and extinguishes sharply.

Hfornblende alternates with biotite in being the more abundant ferro-magnesian mineral. In the main body of the granodiorite it is in excess of biotite, but in the large granodiorite dike the reverse is true. The hornblende is dark green, and pleochroie, and idiomorphic toward the quartz, feldspars, and biotite. Biotite is dark brown, and also strongly pleochroic, and frequently shows a rim of magnetite. It appears in shreds and flakes, which are oceasionally bent and altered to chlorite.

Of the accessory minerals, titanite is most abun lant, in ita characteristic wedge-shaped feebly pleochroie erystals. Other accessories are small grains and crystals of apatite, zircon, magnetite, and pyrite.

A chemical analysis, by M. F. Connor, of a typical specimen showing biotite slightly in excess of hornblende, gives the following results :—

SiO, ye US Gee heron gird or aan QMO tld Wed ten PN seein 62-05 a Ue embark. atl eel. ne tqoie eared eal ee! cae, ce) a ee reOe. SRE BLAS wed bias grey ara! Sige Dh aie wwe pea ELEN Ses als : 1-08 teor FMLeR NWO Ee ras The Sle tate ak FRA eerie eI RCE I oh he 3-08 UO Sees ccicie nmieraiir: Fuacieae Pi ce acy allanien ap nie Nat dn ieee ee SO Je Ree Becca poe Ee ee AED pal Aunt ome Ane ee os ECO ier Tae eer etree eee Ae ag ig Se a mei ml 2°96 CO erect inne Bad ee eee oes Stes (sis ee salle eee te, 0880 Eis sae siarm colores pao oa Sia ed com ee ee eee hae OEE Rie tory teeta ony een eee ee a Cee hae GS Reg sare Sree rs A, Meth MCN pana eae aba ee Ba ON Ge O17 MnO. . 0-11 LAO ie orerieht onror ein eaten ira maa nt ate ae ne Vo EACe BAS crush sreuntn anton halle hc te ee Mateus sty wie ears OES

Caleulation of the norm of this rock, aceordins to the method of Cross, Tddings, Pirsson, and Washington, gives the following percentages :—

EEDLEY MINING DISTRICT! ORE DEPOSITS Ue

Quartz. 8°22 per cent Orthoclase 17-79 ' Wed Sof Spy Ne i . 4 Salic,

Albite eee 42°07 " ed paw 85°04 Salic Anorthite, ., 16°96 'pimeterh areete Diopside. ... 390 : Hypersthene HOT " ana? ; Ilmenite ... wool he eerae 13°31 Femic, Magnetite.. 1°62 " a Apatite. wes

Ba gee Be IRMA IEL rat an sok etaate ee ache oe vo. .Dosalane,

rem 1

& L 1 LUE) oS ae Peat inn Ae Le: eee. Clermanare,

F, wee K,03 Na,O Ls RRO RSet des as renee weeeeeee. Domalkalic, ' g2 CaO 1 EO) a e MUDPANT Qi evar seute yan soe centers Dosodic, Na,O 1°73

The rock, therefore, is akerose. From a thin section of the rock, the was determined by the Rosiwal metho

culty of quickly separating orthocl

actual mineral composition On account of the difii-

ase from plagioclase, because the

latter often shows no albite twinning, the two were classel to-

ecther, and calculated as iotal feldspar. The result is as follows :—

Quartz 19°9] per cent Feldspar... 74-00 ¢ Biotite. .. 7:98

Hornblende dso

It is possible, by combining the results obtained by the Rousiwal

method and the chemical analysis, to make a re-caleulation which

recent the actual mineral composition, including the orthoclase and pl:

the analysis of

probably will give us within one pe

igioclase feldspars. By taking a common varicty of biotite, and

allotting enough K.O in this proportion to make up

7-28 per cent of biotite, and leaving the remainder to go to form orthoclase, we get the

following mode of the essential constituents :— Quartz.. ric Orthoclase., Plagioclase. Biotite;. os a. Hornblende..

According to the Rosenbusch classification of rocks, the roek is

a granodiorite, but one belonging to the b almost a quartz diorite. 9185—7

asie end of the series, and

pees

xa

He) GEOLOGICAL SURVEY, CANADA

Comparison of this rock with the quartz diorite shows a very close relationship between them. In the younger granodiorite there is a higher percentage of SiO, Na,Q, and W.O, and a corresponding 'ower percentage of A1,0,, FeO, and MgO. The younger rock is slightly more siliceous and alkaline. It follows, also, that the

quartz and orthoclase of the mode are higher.

Melamerphism.—The amount of metamorphism, either regional or contact, undergone by the granodiorite, is very limited indeed. There is a slight decomposition and alteration visible in the thin sections of the feldspar constituents, and a slight straining and bending of the biotite flakes. but. apart from this, the rock is almost perfectly fresh. As it is the latest large igneous intrusion jn the district, and it is only cut by small trachyte dikes, it has suffered no

contact metamorphism whatever. STRUCTURAL RELATIONS,

Internal.—The most interesting and evident feature of the internal structure of the granodiorite is that of differentiation, which is exhibited on some of the outer borders of the batholith. While the body of the rock is remarkably uniform throughout, and of a normal character, there is frequently a marked change on its contacts with the older rocks. Figure 2 is an actual section, of the contact of the granodiorite batholith with the Sunnyside limestone, and the upper beds of the Redtop formation. This section is exposed on the northern side of the Similkameen valley, and it is wholly uncovered, except for a few feet at the very base, so that it can easily he mapped and studied.

In passing upward from the normal eranodiorite at the base, toward the contact of the Sunnyside limestone near the western end of the section, a change in the character of tho granodiorite becomes apparent. at a distance of about 30 feet from the contact. In other places along this contact the change takes place at 50 feet, or even more. Here it is noticed that the dark minerals, horn- Llende and biotite, become less abundant. and gradually disappear, until 15 feet away from the limestone none are visible in the rock. The rock then becomes light pink in colour, and very feldspathic— features which it preserves up to the contact. Within 2 feet of the contact, a slight change in texture takes place and the roc). is

noticeably more siliceous. Here 2 porphyritie structure is developed

Prvre vir

wtierite Iblocks

pulostinmxstiisanes™

Hlpley Mining District Ore Deposits 4)

With phenocrysts of quartz embedded in a tine-grained ground-y.4. of pinkish white feldspar, Numerous small seams and stringers of clear white quartz traverse the rock in this zone, and higher in the apophyses. The actual contact with the limestone shows

2 inches of a perfectls white, fine-grained rock, soft but so com)

that the different constituents cannot Le identitied by the eye. Ab this is the sharp clean-cut line of contuet with the limestone, sh tug no blending whatever of the two rocks,

Apophyses of the same character as the contact phase of the #ranodiorite, which are later described under the head of aplites, penetrate the overlying sediments at varios points along the eontact. These are also of a light pink colour, and contain only two Visible constituents quartz, and acid feldspar. They exhibit. very similar characteristics to those of the contaet zon +, namely, the development of a porphyritic structure within 2 feet of the contact, and a soft compact white band at the immediate contact. On following these apophyses out and away from their souree, there is it marked tendency in them to become more and more siliceous, until they piss into very siliceous quartz porphyries. These apophyses, like the contact zone, are cut by many small stringers of white quartz,

Though chemical] analysis of the rocks of this contact is lacking, u study of the field relations, which are alwavs very well exposed, shows that there is a strong tendeney in the granodiorite to ditferentiate on its upper contact to a rock which is more siliceous and much more feldspathic, while the femic minerals remain below in the undifferentiated rock. This differentiation indicates an upward rise of silica, and the alkalis to form quartz and fi ldspar, and a sinking or reé mnaining behind of the iron, magnesia, and lime whieh; vo to make up the femic constituents.

Differentiation on such a seale is not exhibited on the contact of the large 400 ft. dike of granodiorite which runs diagonally aercsthe shoulder of Nickel Plate mountain. This also sends out apophyses of aplite laterally into the adjacent rocks, but they are fewer in number and smaller in size. The contacts with the quartz diorite on the one side, and the sediments of the Nickel Plate formation on the other, are sharp, well-defined lines, and in the hand specimen there appe to be little if any change in texture or composition of the granodion..>, and certainly no development of a contact zone of plite.

Glologtioatl Burvey, Canada

Reasons for the development of a wide aplitie contact zone in the one case, and an entire lack of it in the other, are obtained from a study of the form of the igneous bedy and its underground exten-

ut In the case of the granodiorite dike, it is the lateral eontaet which ia now seen, for the dike stands vertically and the roof has Leen eroded awa Phe contaet exposed in the Similkameen valley, on the other hand, is a roof eontavt. Not only is the eontaet in

the Simill ameen valles aln ost horizontal for ne arly at mile, as shown

i the seetion, but, when it comes to the transverse valley of Twentymile ereek, it turns directly at right angles and is found to run almost horizontally in this direetion for several hundreds of feet,

until it is covered by the gravel deposits of this stream. If the Upper surface, therefore, of th granodisrite batholith wore exposed, it would be found to be an almost flat, or at least not greatly tilted plane. The formation of the aplitie zone, therefore, on the almost Hat upper surface of che batholith, eould be explained by a trapping on this surfaee by the roof of sediments, of the lighter, siliecous and alkaline portions of the magma before it solidified. Some of this would find its way by cracks and fissures into the sediments of the roof to form the apophyses; but the heavier femie minerals remain below. Lateral contacts, such as those exposed on the border of the large dike, or even where the contacts of the main batholith steepen, do not show this aplitie border, beeause the light minerals Which constitute this phase have probably risen beyond to the roof.

A characteristic feature of the granodiorite, in contrast to the other igneous recks of the district, is the presence of many amall rounded or oval-shaped areas of dark basic material, whieh at first sight appear to be inclusions; but since they are soon under the mieroseope to contain only constituents which are essential to the eranodiorite, it is more likely that these are merely differentiation products, and due to the segregation of the femie minerals in certain areas, These segregations are very abundant, and vary in size from 1 ineh up to 4 inches in diameter. This, however, is a feature Which ts common to many granitie recks, net only here but elsewhere.

The granodiorite shows little evidence of having undergone orogenic disturbance, and exhibits no breeciation, cithar mieroseopically or in the field. Neither has it suffered any faulting. Small fissures, a fraction of an inch in width, which have become

filled with quartz or feldspar, and contain also some sulphide mineral,

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traverse it everywhere, and appear to represent cooling the chilled rock, which were soon tilled with material emanat; the cooling magia,

Joint planes have been developed in the rock, so that it readily in four main direetions. These have a bearing of 50 180°, and 295°, only the last of which bears any relation to the

tion of the strongest fractures in this region,

External.—The granodiorite is known to cut every rock format in the district, except the andesite dikes, and these alk Cut the

eranodiorite, Its contacts are, us a rule, well exposed, so that

doubt can be entertained of its relations to the other rocks. These contacts are generally sharp, and show no tendeney to transition from one rock to the other, Its eontact with the sedimentary rocks is well shown in a natural section exposed on the northern slope of the Similkameen valley, and is illustrated in the acco Mpany iw

illustration, Fig. 2. This section shows the sedimentary strata

with the included sheets of diorite porphyry dipping to the north

ut angles of 25° to 30°, and truncated by the eruptive grandiorit

It is difficult to estimate the amount of contact metamorphism

that has been induced in these sedimentary rocks by the grand

diorite, for we know, from comparison, that of meta

morphism must have already been indueed in ntrusion

of the diorite-gabbro and its apophyss. It is c

Vr, that

the granodiorite must have had a great inthucnes uw w about

the result that now obtains in these sediments. Ita. . wed here,

as in the case of the diorite and gabbro contacts, tnat the banded

sediments, whether quartzite, limestone, or tufts, show

much Thiele alteration than the massive limestones. Jn the former, there appears to have been an introduction of siliea. often in a chaleedonie form, and which may have gone to form the lime silicates, while in the latter, there has merely been a crystallization of ealeite near the contact, without the formation of any lime silicates.

A slight mineralization accompanies the granodiorite on thes sedimentary contacts, but it is relatively insignificant, when eorpared with that which accompanies the gabbro, or even t' diorits contact.

The metamorphism induced in the massive diorite formation is very slight indeed. The effect seems to have been much greater in the dike forms of the diorite, where they oecur as sheets in the limentary rocks,

102 Geological Survey, Canada

Comparing the total amount of contact metamorphism etfeeted by the granodiorite with that effected by the diorite-gabbro rocks, we are immediately struck with tho fact that. the metamorphism has heen much greater on the borders of the stocks of gabbro and diorite and their apophyses close to these stocks, than it has been on the

erauodiorite contact. This is all the more strange, because the mass

2 tu

franodiorite is may times greater than that of all the dioriteseks put together. Not only so, but the chemical composition cf ¢!.e granodiorite is so much more acid than that of even the mest aeli phase of the diorite-gabbro, that we should expect greater Contec! metamorphism on the contact of the former than the latter. The difference is due probably to physical rather than chemical factors. The field relations of the granodiorite show that we actually have the roof of a batholith here exposed, and that the contact we now see is one which has only been exposed by the deep erosion of the Similkameen valley. It is probable that by the time the granodiorite magma in its upward course reached its present position it Tad lost a great deal of heat, and was slowly solidifying, losing, at same time, its power to metamorphose the overlying rocks. That it was also heeoming viseous is shown by the small number of apophyses which it sends off into the sedim ntary rocks overlying it. In the diorite-gabbro magma. on the other hand, we only have the lateral contacts, and the magma must have had enough superheat to penetrate upwards, much beyond the exposures whieh we now see, and these contacts must have been exposed to greater heat than the roof contacts of the batholith. The diorite-gabbro magma also was much more fluid, and greater fluidity would indicate greater heat, or the presence of more water or mineralizers. The greater fluidity is shown in the great number of its apophyses, the ease with whieh they penetrate the sediments, the distances which they travel, and the uniformity ef thickness of any one apophysis over great areas. Many of these apophyses are only a few inches thick, but they persist, in spite of their thinness, for ereater distanees than the largest of the granodiorite apophyses. On the hypothesis, therefore, of greater heat and fluidity. and the presence of more abundant mineralizers, it is possible to account for the greater power of meta-

morphism of the diorite-gabbro rocks over that of thy granodiorite.

Mode

Of Origin,

The origin of the granadiorite is analogous to that of the

diorite-gabbro already described, and differs only in its greater

Hedley Mining District? Ore Deposits

size. While the diorite-gabbro rock has been properly desig nated as oceurring in stocks, the granodiorita is mora eorraativ described as a batholith. If the amount of granodiorite shown the geological map represented its total areal extent, it could hardly be called by this name; but it is known to cover a great many square miles of territory outside the limits of the map. Its contacts and particularly those seen in the valley of the Similkameen river—show the nature of its irruption. Plate XI shows the granodiorite vine at the base of the hill with the older sedimentary rocks Iving on top of it, and dipping at an angle of 25° into it. It is impossible to conceive from this contact th. this irruption could have taken place by any simple process of injection, without leaving abundant evidence of general disorder in the sediments above. These rocks, however, appear to be quite undisturbed by this irruption, and retein the dip and strike which they had before. The irruption. therefore, must have been slow and gradual in its action, and this contact seems to illustrate very well the theory of magmatic stoping advaneed by Dr. R. A. Daly? and Barrell? for batholithic intrusions.

The contact shows that the granodiorite lies underneath the sediments all along the slope of the valley, and passes around the shoulder of the hill, ana up into the valley of Twentymile ereels.

A cross section of this would show that the upper surfaee of the

granodiorite, on which the sediments rest, is almost flat. or dips

downward to the north at a very low angle. We have. therefore, the actual roof of a batholith here exposed, and one that froze before it reached the surtave, and has only since been exposed by erosion. From the total extent of this batholith, both inside and outside the district, and from its exposed contacts, we are almost justified in supposing that it underlies a great part of the rocks of the [[medley district at and below the level of the Similkameen river, The ereat extent of this body suggests replacement, rather than simple injection, and its downward enlargement is shown for some distanee. The internal structure and erystallization of the batholith indicate that it cooled before reaching the surface, and its contact has only been laid bare by the erosion of the Similkameen valley.

It is not absolutely certain whether the large dike of granodiorite Which extends from Eighteenmile ercek across to Twentymile ereck

'Mechanics of Igneous Intrusion, A. J. SiO oo) pa dey 20ne: U.S. Geol. Surv., Prof. Paner No,

104 Geological Survey, Canada

his a similar origin or not, but it is thought, from its following one of the main lines of weakness in the district, that its origin is more of the nature of an injection along this line of weakness. This dike follows the same jine as one of the main reaches of Twentymile ereek, and while no faulting or displacement is apparent in the Twentymile valley there is some evidence of a slight displacement in the part of the line oecupied by the dike. The conclusion drawn from a study of this dike is that the fracture was formed before the eruption of the granodiorite, and when this event did happen, a portion of the magma was thrust into this line of weakness to form the dike.

Age And Correlation,

As in the ease of the diorite-gabbro complex, only the relative age of the grand Horite is known with certainty, We know that it follows the diorite-gabbro in point of — time, but there are no younger rocks the age of which is definitely known, until we come to the glacial deposits. Structural features are again the only grounds on which any estimate of age can be based. These are, however, generally of a negative character, The rock has apparently suffered very little from orogenic disturbance, and in the thin sections no straining, breeciation. or granulation is apparent. Gneissic structure is also entirely wanting. The fact that the dike-like mass of this rock has been thrust into a plane of dislocation suggests that this dislocation must have taken place prior to the intrusion of the granodiorite. This dislocation and disturbance is referred to the period of orogenic disturbance at the close of the Laramie, and, therefore, the granodiorite irruption must be at least post-Laramie in age.

Batholithic intrusions of granite, granodiorite, and other igneous rocks have been carefully studied by Dr, R.A, Daly, on the International Boundary line, about 20 miles to the south of this district, and these are all united into one composite batholith with a width of 60 miles! Certain of the members of this composite batholith have heen referred by Dr. Daiyv to a period later than the post-Laramie

deformation, and while they may be totally different in composition

to the granodiorite here deseribed, it is probable that they may he

referred to the same period of batholithic intrusion. i

teagan) Dee trite Creine Ate Arey ents Pp. 826-376,

HEDLEY MINING DISTRICT? ORE DLpostrs

Dike Rocks,

Lamprophyres.—The lamprophyres of the district are dark. tine to medium grained rocks, found only in small dikes, which are rarely over 3 fect in width. They are composed essentially of feldsp and idiomorphie erystals of hornblende or augite, with or without a fine-grained ground-mass. The trend of the dikes is not uniform Lut varies through an are of 60°, that is to say, from N 75 FE t 845° E. They occupy tightly closed fissures, and while some of th: Mm are known to occupy fault planes, others fill subsidiary fissures which have a tendeney to parallelism with the fault planes. They are not remarkable for their persistence, either in extension or in direction.

On account of their small size, and the readiness with which they decompose they are not conspicuous in the topography. {ome

are found in the underground mine workings which are concealed on

the surface by drift. The majority of these dikes were found to the

east and northeast of Climax bluff, and all within a radius of threequarters of a mile. They are mostly found cutting the sedimentary rocks. A few were found cutting the gabbro and diorite stoeks, but none are intrusive into the granodiorite.

The lamprophyres show considerable Variation in megascopie appe A common type is a fine and even-grained rock, showing abundant crystals of feldspar, and either hornblende or pyroxene, Tn other specimens, both the ferro-magnesian minerals and the feldspar show a decided porphyritic structure, which is most marked in the hornblende-bearing rock. In these the ground-mass is very fine and almost aphanitie.

The microscope shows these lamprophyres to be long to two distinet types—a_ kersantite and 2 camptonite, one in which hornblende and hiotite ave the dominant femie minerals, and another in whieh pyroxene holds that position. The essential constituents of each of these types are plagioclase, hornblende. and biotite in the one ease, and plagioclase and pyroxene, with subordinate horablende and biotite. in the other case, Some orthoclase js generally present in each of these types, and in the former, quartz is sometimes a subordinate constituent.

Plagioclase is the most abundant constituent in all the rocks, both as phenocrysts, and in the ground-mass. Hornblende or augite is second in importance. The biotite when it is present is found

only rarely as phenocrysts, but usually in the ground-mass in small

L106 Geological Survey, Canada

flakes, where it is relatively abundant. In sections where pyroxene

eceurs, it takes the place of hornblende to a very large extent, and

the hornblende becomes quite secondary in quantity. The plagio-

clase. hornblende, and pyroxene show as a rule, good crystal form, though the plagioclase is often obseured by small inclusions or by alteration. As accessory minerals, magnetite and titanite are abundant in all sections, and quartz in only a few. Secondary minerals are chlorite. epidote, and ecaleite, the first being very abundant in the augite 'caring varieties. The texture in both kersantites and camptonites might be either porphyritie or panidiomorphie.

The plagioelase crystals are medium basie, and show no zonal structure as in the plutonic rocks. Albite twinning is not very eommon, or else it is obscured by the formation of secondary minerals. Twinning after the Carlsbad law, however, is very common. The hornblende of the kersantites is dark to light green, and not strongly pleochroic. It is usually quite fresh, but sometimes goes over to epidote or shows a tendeney to alter to chlorite. The pyroxene has the typical augite habit, forming tabular ervstals of very pale green colour, similar to the plutonie variety found in the gabbro. It is very resistant to weathering, and rarely goes to hornblende, though more often to chlorite, In the typical eamptonites, chlorite is very abundant, and, with sme ealeite that occurs with it, is the result of alteration. It appears as a pale green °jineral, generally isotropic ia Character, and of low index of refraction. It less often has a weak double refraction, and is then seen to be made up of a felted mass of intergrown fibres. The intimate intergrowth of these fibres probably aecounts for its anomalous isotropism. Calcite is also associated with the chlorite as a secondary mineral. Titanite is very abundant, mere so in the camptomites than the kersantites, and is always associated with the pyroxene in small wedge-shaped faintly pleochroie erystals.

In age, the lamaprophyres follow, apparently at a short interval, the intrusion of the stocks of diorite and gabbro, but they are not

found intrusive into the granodiorite.

Keratophyre.—Certain rare dike rocks, always referred to in the field by the name of quartz porphyries, are better designated by the more restricted name keratophyre, a rock intermediate between the

porphyries and porphyrites. These rocks also have affinities to the

HEDLEY MINING DISTRIC PP) ORE DEPOs Ts 107

trachytes, but are quartz-bearing. In the hand specimen, t

is dark, fine-grained, and dense, and of a slightly porphyrit ic rT ture, showing phenocrysts of glassy quartz and twinned feldspar embedded in a dark and almost glassy ground-mass, The best je locality where this reck oceurs is in the Nickel Plate mine, where it is found as a dike 4 to 6 feet wide. Iving to the south and west

of the main ore body, and forming its boundaries on these fos, It has no uniformity of strike. but in the above locality it seems 1; curve about so as to form the are of a quadrant,

Under the mieroseope, the rock is seen to be made up almost, cntirely of feldspar, both as phenoerysts and in the ground-mass. Its structure is porphyritie, and the prevailing phenoeryst is an acid plagioclase, which cannot be Jetermined more specifically. Large, clear, glassy phenocrysts of quartz are also present, but are much less abundant than the feldspar, and these invariably show rounded and corroded outlines with embayments of the ground-mass in them. The texture of the ground-mass is very fine, though ervystalline, the indisiduals being very irregular in outline and intergrown with each other, The constituents ef the ground-mass are largely feldspars, all untwinned, and of an apparently alkaline variety. Some quartz is also present in the ground-mass, and a ferro-magnesian mineral Which is probably hornblende. Accessories, in the form of sulphides, are sparingly presen, bat on account of tho proximity to th ore bodies may be of — 'ondary origin,

The age of the 1. is determinable only within wide limits. It is known to ent the Palwozoie sediments, and the inirusive sheets and apophyses from the diorite and gabbro stocks. On the other hand, it is cut by the andesite dikes which are the youngest rocks in the district. Its relation to the granoliorita batholith is unknown. From its general character and appearance it is probably older than the granodiorite, and until further evidence is obtained is tentatively referred to the period following the irruption of the

stocks of diorite and gabbro.

Aplite and Rhyolite-—The aplites are dikes or aupophyses @eneti eally connected with the granodiorite batholith, and having a porphyritie structure, with phenocrysts of quartz and feldspar embedded in a fine-grained acid matrix. With theae are associated some 'hyo-

lite dikes, for both are thought to be modifications of the same

10s GEOLOGICAL SURVEY, CANADA

granodiorite magma. and referred to the same general geological age.

The aplites are easily recognized by their light pinkish colour, and their frequently speckled or porphyritie appearance, They have not any marked uniformity of strike or s}) +, and are generally found at no great distance from the edge of the granodiorit: batholith. To the east of the stamp mill several of these intrusions can be traced directly from the granodiorite, running off as tongues into the overlying sediments. In these cases they are not of great length, and quickly diminish in size and pinch out. Others of the same character are noted ia connexion with the dike like mass of granodiorite crossing the gravity tram-line above Central station.

Pinkish rhyolite dikes, showing no erystalline texture to the unaided eye, are found on the Stemwinder hill, and on the Kingston mineral claim. These have a general north and south trend, and are more persistent in distance than the aplites. They eut all the rocks of this distriet, sedimentary and igneous, except the andesite dikes.

The aplite is a reddish or pinkish rock, having a speckled appearance, which cannot be confused with any other rock in the district. It contains erystals of quartz and feldspar, and sometimes mica embedded in a fine-grained ground-mass that is aimost or quite aphanitie. Under the microscope the dominant phenoervsts are found to be feldspar, both orthoelase and plagioclase, with quartz, the latter showing the characteristic corroded outlines. Much less abundant are crystals of mica in large individuals. Mica, however, is absent in many of the aplites. and the only phenocrysts are these quartz and feldspar. The ground-mass is generally a minutely crystalline aggregate of quartz and untwinned feldspar, which is, however, quite distinct in character from the ground-mass of the dikes of rhyelite.

In the rhyolite dikes, while the texture is somewhat similar to the aplites, the phenocrysts are much less abundant. Like the aplites, however, the phenocrysts are quartz, orthoclase, and plagio-

clase. These are embedded in a very fine-grained acid ground-mass, the components of which cannot be accurately determined. There is a pronounced fluxion structure to the rock mass, which is accentuated by the presence of a dark opaque substance, which

is arranged in rudely parallel lines. The ground-mass also shows

HEDLEY MINING DiIs'tPp ORE DEPOsT] 1

frequently large shadowy erystals, which under crossed a patchy wavy extinetion, These are thought to be the 1 devitrifieation of a glassy ground-mass, and this, in Coajunet the tluxion structure, seems enough to justify the elassiticat the reck as a rhyolite

The aplites and rhyolites are closely conneeted with the int: of the granodiorite, and in the ease of the aplites are seen ty be simply apophyses originating in the ygranodiorite and penetrate: the older rocks ac dikes which do not persist very far. They

therefore, contemporaneous with the granodiorite,

Andesites.—The andesites are light to dark green rocks, generally of very fine grain, or only slightly porphyritie, occurring in dikes up to 8 feet in width. They are very soft roeks, and where ex posed are noted as occupying depressions rather than forming ridues They are much more persistent than any of the other dikes, and are also mrore uniform in strike. This trike varies ony from about N 1b) Woto NOS? EB and is not moticeably conformable with ans of the great fault planes.

These dikes are not abundant, but are found both in the Sunnyside and Nickel Plate mines, cutting the ore bodies, and were noted also at Bradshaw ecafion, and to the east of the Daly Reduction Company's stamp mill. They eut all the rocks of the district, both igneous and sedimentary, without any exception,

In the hand specimens, these rocks are light to dark groen in colour, They oceasionally show a porphyritie structure, but more often consist of small fine needles of black hornblende and elisten: ing laths of feldspar, closely compacted together, and with a tendeney to parallel arrangement. The ground-mass is aphanitie, and quite indeterminate.

Under the microscope, they are seen to consist essentially of two constituents—feldspar and hornblende. These two constituents occasionally oeeur as phenoerysts in a ground-mass of the same components The feldspars are long and lath-shaped, and are plagioclase of the variety andesine or oligoclase. They show only a little variation in size, and the larger ones are only 0.3 of a millimetre in length. The hornblendes are not so abundant as the feldspars, and when they oceur in phenoerysts are generally much altered. These two constituents are, as a rule, arranged with their long axes rough!s parallel to each other, and have a marked trachytie structure. Aug-

110 Geological Survey, Canada

ite is sometimes abundant in small grains, but there is never any biotite. Titanite is an abundant accessory constituent, and there is often much magnetite.

The ground-mass is holocrystalline, but occasionally shows some glassy residue. It is composed of small feldspar laths and small green hornblendes. The feldspars show some decomposition. Augite is rare, and when present quite unaltered. The hornblende shows a great deal of alteration to chlorite, particularly in the phenocrysts. Calcite and epidote are also common as secondary products.

In age, the andesites are the youngest consolidated rocks in the district. They are known to cut the Palwozoic sedimentary rocks, as well as the diorite and gabbro stocks and the granodiorite. They are, therefore, at least Tertiary in age, and may be connected with the extrusive lava flows of middle or later Tertiary age, which have such a wide distribution in neighbouring portions of she Sirmilka+ meen district.

Surbace Deposits,

The only rocks in the Hedley map younger than the sedimentary rocks of the Cache Creek group, and the igneous rocks already described, are the unconsolidated glacial and stream deposits. These are not of any economic importance, and consequently have not been closely studied. The stream deposits only are of sufficient importance and extent to be mapped and outlined by a separate colour on

the geological sheet.

Glacial Deposits —The former existence of a Cerdilleran ice sheet, covering the whole of the Similkameen district, preceded and followed by valley glaciers, has frequently been referred to. Evidence of the presence of this glacial ice is preserved to us in the broad U- shaped valley of the Similkameen river, and also in the deposits left behind on the plateau on the retreat of the ice. These deposits are of limited extent, and not well defined, so that it would be impossible, or very difficult to map them. They consist cf glacial debris, quite unassorted, and lying as a thin mantle over a great part of the map. Large granite boulders brought down by the ice from the granite areas to the north are seattered over the whole area, and up to the highest point in it.

Stream Deposits.—The stream deposits are easily distinguished

from the other drift deposits, though occasionally at the base of

f

p. 110

Iss

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Adtnatatsndenesnannusanimneubil ite aalinbeatiod isl SMe Muanininiwanididi acne dubs vate bie

Hepeley Mining District! Ore Deposits Bb

the steeper =lopes they merge with, or are covered by the ta

the cliffs, In the Similkameen valley they form a broad bay about 3,000 feet across, and of unknown but probably great de pth. teh been roughly estimated, by projecting the slope of the

beneath the stream denosits, that the thiekness of these in

of the valley must be at least 300 feet. This gives a total amount of alluvial deposits quite out ef proportion to the present size of thy stream, This fact indicates a former period of rapid deposition,

a valley deeper than the present one, by a stream overloaded with debris, and greater than the present one, This period belongs to a time immediately following the retreat of the glaciers, when the stream was laden with glacial debris. At a later stage in its hi ory, the stream began to cut down into the gravels previously deposited by itself, and numerous benches were found, which mark successive stages in this process, On the west side of the mouth of Twentyniile creek almost a dozen such benches can be couuted, each rising only a few feet Sigher than the lower one. The highest of these benches at Hedley stands at an elevation of about 1,700 feet above sea-level, while the present level of the water in the river is about 1,560 feet, or 140 feet below.

These benches are made up of well rounded boulders of large size, lying under about 6 inches of light coloured sandy soil, Asa ciated with these gravels are beds of almost white fine-grained silt, which probably represent stationary conditions for a short time, or deposition in the quiet waters of a lake. On the banks of Twentymile creek, to the northeast of the town, a section of thes stream deposits, 40 feet in thickness, is exposed in a cliff, (See Plate XIII.) The upper beds of this cliff, which is just below the 1.700 ft. contour line, are made up of angular as well as rounded 'boulders, showing some evidence of stratification. These are interstratified with beds of finer material, almost sand, and quite distinct

trom the beds of coarser material. Below this are about 16 inel

of y fine white silt, which has an elevation of 1,680 feet above sea-level. Underneath this silt bed are beds of sand and gravel, similar to those above. More extensive deposits of white silt were noted in the upper portion of Twentymile creek, but outside the map. These were at an elevation approximately measured by eneroid of 3,000 feet above sea-level, This js somewhat higher than

similar deposits of this kind mentioned by Dawson, but they are pro-

Bs Geological Survey, Canada

bably of a like of ht ¥, clepositiom in th jules ite i

lake curing or after tinal retreat of the glacier from thia region

STHECTURAL GhobLOGY

Phe different kinds of strueture shown in the roel i the both inelude faults, folds, tis<ur ind joint lhe most important of these are folds and fai The actual folds seen are of small dimensions, but it is believed iat the whol eries of sedimentary rocks represented in the nap merely the we rn limb of a great anti-

cline. whe eastern limb is to be found on the eastora side of

Hitescuitenl pes 'ited eo rest ta been largely eroded gayouas or truncated by igneous intrusions, The general strike of all these

folds is in a northerly dircetion. Faults are not as numerous ag minht be ENP ted from the munabe of iuneou intrusions, atl nls

at of these have been reeornizel ia ths field, and mappol.

Undoubtedly many more occur, which have not been detected, No nhitormity of direetion has been reeognized in the strike of these faults, though the main faults of the region, on which the direction

of 'Pwentymile creek te 1 extent depends, have a strike of N

PoLDS. There is a general uniformity of dip to the west of all the sediientary recks in the region. 'This, as before stated, is a faet which i ssochituc ith the id that all the ro rely represent one t ' turting at tl ' hi th ] the dips are very high, and often vertical, and going eastward neross It, these dips gradually tlatteni out, until on the eastern sl ot the Nicke Pilate on tain tl ire nl wmeut 15 to the west. Farther eastward they appear to dip in the other direction

altogether, The original crest of this anticline was probably over bed of Eightes il creek, and the vener trend ot ts about north south. 'This is the general trend of the Okanagan range of mountains, though there is no genetic ¢ nhexton between the two. This anticlinal fold was produeed during the first known

reformation of the region, and long before the Pliocene uplift which produced the Okanagan mountains. The compressive forces, however, to which the uplift was due in both eases, were exerted in a general east and west direction, in conformity with tho other great

movements of the Cordilleran region.

HEDLEY ' re ecu es Ga Pb bt

Apart from this m Wor fold, thers ary many folds order, all of heh are tiot so elearl ot th OrLEL fold. These are best exhibited in the siliesous tad ar via rtions of the series, and are yeon in Redtop guleh, in eafon, and on the face of Striped mountain. ALL of thes closely compressed, and some are faulted along the axis cline, The massive limestone tnembers associated with eeou ind argull ceous beds have not, for some re ion, bee by these forces, and they preserve their uniformity of dip 4 therm. The axes of these miner folds ec nform ino oa general with the axis of the main inticline, Compressive stresses at right angles to theso have prolaced a

second group of minor folds consisting of low antielines anil ayn

clines, with east and west axes. and in these the maksive Hmesto: beds are involved. 4 well as the adjoining siliceous and arcillar beds. Compression in this direction has been very mueh weaker

than in the north and south dircet; mm, and the resulting low folds are well exhibited in the neighbourhood of the Sunnyside Mh

nd on the face of Stemwinder hill.

Faults,

Character and Distribution. The second result of deform n in this region is the series of faults that cut across the formations. As might be expected, the largest proportion of these are 30 small that they are not worth while mapping. Faults were noted which have a throw of 1 ineh only, while the great Bradshaw fault has a throw of at least 800 feet. Many others intermediate betwer n these two extremes are to be seen in different parts of the region.

As a rule, the plane of the fault is a clean cut break attended hy little local disturbance of the adjoining strata, and this is characteristic of the faults of smaller magnitude. In a few cases there ir to be seen a slight bending of the adjoining beds, due to friction, and a dragging down of the displaced masses. This js shown in the fault Iving under the trestle at the head of the Horsetly gulch, where the ends of tho strata on the upthrow side are bent down by the dragging foree of the strata on the other sid of the fault line.

Other common accompaniments of faulting are the breecia: which are the result of the friction of one sid> against the other.

114 Geological Survey, Canada

A breccia of this character is seen in a narrow fault plane running diagonally down the face of Stemwinder hill in a direction about No80° FE. The fault plane has in this case been later occupied by a dike. In the Bradshaw fault the plane of the fault lies in the bottom of the cafion, and is masked by the drift and talus in the cation bed. No friction breccia was apparent, but in a thin section of the mica diorite dike lying to the west of the cafion a crushed and brecciated appearance is exhibited in the minerals making up the section. If this microscopic brecciation is due to faulting—-and, it is a plausible'cause—then we know the relutive age of the fault-, ing. feature allied to this friction brecciation is seen in the northern end of the Nickel Plate mine workings. There is a zone of fracturing here running N 70° W which is marked on, the surface by a depression, and while there may not be any actual displacement of adjoining strata, there has been rather strong fracturing tending toward faulting. The Nickel Plate ore body adjoins this fault zone on the west, and whereas the fault zone has not been mineralized by the solutions which produced the ore bodies, we havo in this case, also, a clue to the relative age of the faulting. The most apparent, and at the same time the greatest fault in the wholo district, is that which has already been referred to as the Bradshaw fault. The plane of this has a direction of N 30° E, and it follows the main branch of the Bradshaw cafon from Twentymile creek in almost a straight line to the top of Aberdeen ridge. (See Plate XIV.) Its course in the upper portion is marked by a cation covered with a light yellow talus. The dip of this fault plane is very high, and the downthrow is on the west. It was found very diteult to calculate the amount cf displacement in this fault, because the conditions were complicated by the presence of two other faults on the east side, apparently tributary, and running into the main fault. In contrast to the Bradshaw fault, 'the upthrow side of each of these two is on the west, and the displacement is measured in hundreds of feet. Each fault is marked by a narrow box cafion, in the lower one of which is a small water-fall. The result of all this faulting in the Bradshaw cajion has been to thrust up a large triangular block of the Nickel Plate formation between the two outer fault planes, so that the'top of the Sunnyside limestone has been brought, at the waterfall, directly against the lower beds of the Red Mountain formation, and on the other side against the upper Red Mountain beds. The total result, as repre-

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Hedley Mining Districts Ore Deposits 115

sented in the cation below the point where the tributary fault runs into the main one, has been to bring the Sunnyside limestone, itself directly against the lower voleanie beds of the Red Mountain formation, giving a total displacement of about S00 teet.

A fault of considerably less magnitude, but one easily recognized is that running down the deep and narrow Climax. eajon. The Cirection of this is about northwest, and is probably a continuation) of the line of weakness represciited by the fault at the head of th: Horsetly gulch. This fault plane 'is also steply ineline 1, having its downthrow side to the south. Where expos:1 by prospecting operations, it is seen to be a clean cut break without any accompanying friction breccia. '

Almost parallel to the fault plane of the Climax cation is the strike of the granodiorite dike which runs diagonally across the mountain from Eightecnmile creek almost to Twentymile. If this line were produced to the northwest it would be found to fall into the bed of Twentymile creek above the first bend. These facts are significant, and 'while no vertical or horizontal displace nent is apparent along this line to show that there has been faulting, the fact that two such structural features as a large dike and a deep cation lie in the same line, indicates that there is here at least. a line of :weakness which determine! th preszne: of both these features. Also, the fact. that faulting has taken place along a plane parallel to this line 'suggests the possibility of there having been faulting here,

An excellent exaiuple of repeated normal faulting is furnished by the exposure of yoleanie rocks to the south of Central station. There are three distinct faults, each marked by a short dip in the contour of the surface. and each with downthrow to the south of from 20 to'50 feet. The result of this js a repetition of strata as one walks. across the strike of the faults in a southerly direction,

Topographical Expression.—All of the apparent and easily studied faults of the region have very high or vertical dips, consequently it is difficult to determine fron surface exposure the nature of the dislocation, that ic to say, whether the upthrow side hasbeen thrust upward while the downthrow remained stationary, or whether there has been a simple splitting, with a sinking of the downthrow side, while the upthrow remain1 Stationary. The primitive topegraphie expression of faults cf this nature, before

9185—§!

116 Geological Survey, Canada

subdued by erosion, would be a simple cliff, but it is obvious that such expression could only be found in very recent faults or in regions where erosive action is weak. Erosion would tend to destroy this feature as time went on, first by a filling in with talus from the cliff, and later by a smoothing down of the cliff itself. Evidence of such primitive forms is still preserved in the ease of several of the faults, though very much subdued by the forces of erosion. They now exhibit various degrees of erosion, but it would not be safe to attempt to estimate the age of these faults from the maturity of their erosional form, for the rocks through whieh they cut are of varying degrees of hardness. The Bradshaw fault still preserves to a limited degree tho original topographie form, but this is now very much subdued. In the ease of the Climax fault, and the Stemwinder fault, the primitive cliff-like form is still to a great extent preserved, and if all things were equal, we should say that these two were very much more recent than the other. As a matter of fact, cach of the two Jatter faults lie in rocks which are much more resistant to weathering than the other.

Another topographie expression, and one which app2ars to be connected with most of the faults in the region, is the formation ot deep sharp cafions or gentle sags in the surface of the ground. The former is illustrated in the'case of the Bradshaw and Climax faults, and the latter in the case of certain faults lying to the north of the Nickel Plate mine. This feature has, to a very large extent. governed the whole system of drainage throughout the district, and in many cases the water courses now follow the fault planes. Twentymile creek has been already mentioned as following in its lower part tne strike of the Bradshaw fault, and it is very probable that the course of the stream was influenced by reason of the line of weakness along which the faults had taken place.

Age and Cause of Faulting—The Jack of any sedimentary strata younger than the oldest rock is a great drawback in fixing definitely any event in the subsequent geological history of the region. So it is with regard to the age of these faults. Some of the faults seen on the southern face of the mountain overlooking the river can without' doubt he referred to the time when these rocks were folded, for they are simply the result of close folding pushed beyond the breaking point of the strata. These are undoubtedly the oldest faults in the region. The most apparent faults,

HEDLEY MINING DISTRICT: ORE DEPOSITS ib hg

and those which still retain, though in a mature state, the origina! topographic form, are of a more recent date. These cut all the rocks in the region, except the granodiorite, and the relation of many of them to the granodiorite could not always be determined, on account of an absence of faulting in that vicinity. The opinion was formed from a study of all the conditions that the majority of the faults ar quite recent in age, some being formed previous to the granodiorite intrusion, or accompanying it, and some probably later.

Nteasons for this are that the faults still preserve, to a certain extent, their primitive topographie form. That some of them are earlier in age than the intr sion of the granodiorite is proved by the fact that a dike of this rock occupies one of the principal fault planes, namely that running N uv' W. At the same time a fault with a strike of N 80° E is filled 'y an aplite dike which is thought to be genetically connected with the granodiorite intrusion. That some of the faults are later than the granodiorite intrusion is suggested by the fact that their fault zones show no evidence of cementation or silicification of the friction breccia, a phenomena which might be expected to accompany the intrusion of such a large batholithic mass as the granodiorite. It is certain that most of the great faults in the region are later than the formation of the ore bodies

; and this fact must constantly be borne in mind by the miner, foz it may have an important bearing on the problem of working the cre bodies.

With regard to the cause of faulting, doubtless many of the earlier faults could be referred to causes accompanying the intrusion of the different igneous masses, but for those later than the igneous rocks, some other force is necessary. The latest recorded orozenie movement that might have produced these faults was the Caseade uplift of Pliocene date. The nature of this uplift was such that vertical faults, like those recorded in the Hedley sheet, might readily he produced by such a simple warping, without lateral compression.

Fissures.

Fissures are of little importance in the economie geology cf the region, and though fairly abundant, are generally of small size, and workable ore bodies have yet to be discovered in them. They are probably due to the same causes that produced the faults. but operating with different degrees of intensity. This does not

118 Geological Survey, Canada

imply that they were produced at the same time, though many of these fissures have the same strike as some of the faults. The most sronounced fissuriug is about N 3o I, or parallel to the great Bradshaw fault. Examples of this are seen in both the Nickel Plate and Sunnyside mine These show little or no evidence of mineralization by the metals, and are, therefore, presumably much later than the formation of the ore bodies, Another strong line of fissuring is about northwest, and an example of this is seen in the Nickel Plate mine behind the bunk house. This is a well marked and strong fissure, filled merely with soft clay, and carrying a slight gold value in certain places. The tissuring is evidently quite recent, and much later than the formation of the ore bodies the small gold value in the vein being accounted for by a leaching of the strata through which the fissure runs. Another fairly pronounced fissuring has a strike of N 60° E, JOINTS.

Jointing is best exhibited in the massive granoliorite in the bottom of the Similkameen valley, but the direction of the joint planes was not found to conform to the three well marked lines of fissuring. The forces which produced these two features appear to have been quite distinct, and independent of each other. Four well marked planes of jointing were noted and the bearings of these were N 50° E, N 80° E, 8 65° BE, and south. The two stronger directions were N 50° E and N so? FE, A discussion of the cause of this jointing would be of a purely theoretical nature, and sufficient data were not obtained for this purpose,

Geologic History,

Introductory Statement.—The earliest events in the geological history of the Hedley area are not now recorded in the rocks that are expose' on the surface, and it is doubtful if records of these events will eve: be discovered. Batholithie irruptions of igneous rocks have been instrumental in obliterating much, and it is probable that they may have totally destroyed all of the earlier records even outside the sheet.

The old land, from the erosion of which the Cache Creek sediments were derived, probably lay to the east of here, rather than to the west. The nearest area of supposed Archean rocks is to be found en the eastern shore of Okanagan lake, about: 20 miles to the east,

' ; t t t f

HEDLEY MINING DISTRICT: ORE DEPOSITS Lit

but the intervening country is virtually unknown, geciogically, It is presumed, however, that this Arehiean area was a land mass from the earliest times, and continued so through all the geologic history of southern British Columbia, forming an axis on either sidg ot which later sediments were laid down,

Evidence obtained trom the pyroclastic rocks interstratitied with the sediments shows that these rocks were derived from a volcanic source, east or northeast of the sheet, and at no very great distance The characters of these pyroclastic rocks also indicate active vol eanie vents standing above the level of the water, either as islands or on the edge of the old continent, and discharging their ash and ether materials into the neighbouring seas. which were also depusiting their normal load of quartzites, argillites, or limestone. In this we have corroboration for the idea that the Cache Creck sediments originated from the erosion of land to the east.

An indefinitely long period of time is necessary for the deposition of all these sediments, and as in the case of the beginning, the end of this period is not recorded inside the sh. ot itself, and may be destzoyed outside the sheet by later igneous intrusions. Finally, when this period was definitely closed, and the uplift followed, there

no evidence to show that there was ever again a sinking of this part low enough to allow the sea to encroach for the formation of other sediments. Consequently, from that period almost up to the present, there is virtually nothing by which to tix definitely any events in the history of the region. Within this time there were intrusions of different kinda of igneous rocks, followed or aceompanied by tilting, faulting, and other deformation of strata.

After these things were accomplished, we know that there was regional uplift and glaciation accompanied by a great deal of erosion at all times. The later stages of all this are now reeorded in the present forms of the land surface, and in the superticial deposits of the valleys, ete.

The geological history thus outlined may be divided for conventence, into three periods: (1) Cache Creek sedimentation; (2) Intrusion and deformation; and (3) Glaciation and development of the present topography.

Cache Creek Sedimentation.—The general conditions under which

the Cache Creek sediments were laid down ean be inferred from a study of the characters of these sedi:agents. The main facts that

Geological Survey, Canada

throw light on these conditions are: (1) the ec iformable sequence

through great thickness of strata

(2) the fineness of materials in these strata:

(3) the sudden changes from one kind of sediment to

and (4) the presence of voleanie materials throughout. These facts indicate that there fuffie

'nother;

were ho great orogenic movements ient to produce any uncoaformity in sedimentation, though the frequent sudden changes fron limestone to quartzite might indicate minor oscillations of level; but not sufficient to raise this surface completely or much above s a-level. Again, the fineness of materials indicates either a considerable distance from shore, or more probably ® low relief to the land from which the sediments were derived, so that erosion was very gentle. Also, the presence of voleanic materials indicates frequent and sometimes long continued periods of explosive veleanic activity, with Simultaneous deposition of the voleanic materials with the true sediments,

The absence of any evident unconformity throug

h many thousands of feet of

sediments, demands for their formation

a sinking sea bottom, which, however, did not maintain an even uniform pace, but one in which there were numerous pauses and even rises of level, An insta one of these rises was sufficiently high to glomerate, and though this might indie mentation for a time, no unconformity

The different formations

nee is on record where form a fine-grained conate a discontinuity of sediis apparent.

represented on the map have each some

peculiarity, under which deposition took place.

Redtop Epoch.—The lowest accumulated in clear water deposited.

portion of this formation was , Where the Stevenson lisaestone was This represents a long period of conditions. Following this, in the middle there was, on the whole

stable and quiescent portion of the formation,

, a change to shallower water conditions, with

only oceasionally reversions to clear wate

r conditions of limes' one

deposition. Accompanying this, a period of explosive voleanie

activity was ushered in, which ¢ the deposition of all the sedime the close of the epoch, there

ontinued intermittently throughout nts represented in the area. Toward was a slow sinking of

the sea floor, during which there were many halts or

changes in sedimentation, and from active volcanoes, the fragments from which were blown out and fel] in the sea, became interstratified with the true sediments,

throughout all, frequent outbursts ash and

where they

Sr er rag om cemege

HEDLEY MINING DISTRICT: ORE DEPOSI Ts Le]

Nickel Plate Epoch.—This period is virtually a repition of events as they happened in the preceding epoch, with almost a total elimination of voleanie activity in some sections, The length of time however, during which clear water conditions prevailed, was relatively longer, and consequently a greater quantity and thicker beds of limestone were deposited. The base of this formation, namely the Sunnyside limestone, is the most massive and thickest limestone member in the whole Cache Creek group here represented, indicat ing a very long period of stable clear water conditions. The middle of the formation shows again frequent changes in the sediments, denoting in this case, changes in sedimentation, and not intermitt nt voleanic outbursts. These changes were not so sudden as the outcrops would suggest by the sharpness of the bounding line between the different beds, but the microscope shows rather a transition by a mingling of constituents near the contact.

Before the close of the Nickel Plate epoch, voleanie explosions of great importance, but localized, took place, and a series of voleanie tuffs and breccias were deposited in the upper part of the formation, directly below the Kingston limestone member. The closing stage of this epoch was one of quiet sedimentation when the sea had again advanced to a higher level,

Red Mountain Epoch.—This was a relatively short period of time, but one of catastrophic events. The lower part of the formation—that intercalated with the Nickel Plate formation—has already been mentioned. At the close of the period represented by the Kingston limestone, there appears to have been a very sudden rise of level, which is recorded in the conglomerate streaks that are found in the upper part of this limestone; and simultaneously with this rise was the beginning of the greatest and longest period of vuleanism that is recorded in the history of the whole area. This rise was not a regional uplift of the whole sea floor, but rather a local uplift of a small portion of the country to the northeast, where it is supposed the voleanic vents were situated from which the tuffs and breccias were derived. This may have tilted the northeast portion of the area, so that it became a land surface, while the western portion certainly yet remained submerged, and the normal processes of sedimentation here continued. In harmony with this hypothesis is the fact of the appearance of the conglomerate streaks in the limestone in the northeast portion of the area, and the evident thickening of the

12y GEOLOGICAL SURVEY, CANADA

veleanie beds in the sume direetion This period was not closed by any sudden cessation of voleanie activity; but, by a gradual diminution in intensity, and a lengthening of the time between successive

outbursts, it passed gradually into the Aberdeen epoch,

Aberdeen Epoch,—This is characterized throughout by rapid aud sudden changes in deposition, represented by the alternation of different kinds of rock, Some of the changes might indicate either oscillations of level, or simple changes of sedimentation, but at the 'ume time, a great many of them record intermittent explosive outbursts of voleanie activity. The rocks show that there were never any very long periods of stable conditions, when one particular kind of sediment might have been deposited, but there were frequent changes; and many of the changes of sedimentation were accom-

panied by voleanie aetion,

Intrestion And Depormation,

The elose of the deposition of the Cache Creek group was probably brought about by an uplift of the whole region, for no younger sedimentary recks are now found above these; and from that time on to the present, the region shows no evidence of having been submerged, and has probably been subject to continued and uninterrupted erosion.

Igneous intrusions of various kinds of rocks, with numerous dikes, followed the uplift. The exact time in geological history when the igneous intrusions took place is net known, and all we ean say is that they are post-Carboniferous and pre-Quaternary. The sequence, however, in which the different intrusions followed each other has been worked out in all eases, except in that of some of the vounger dike intrusives,

The oldest of these igneous rocks are the diorite and gabbro reeks, which were previously shown to have been irrupted et. two different periods closely following each other. The nature of the crystallization of these rocks indicates that the surface now exposed must have been at considerable depth when cooling was effected, and they have since undergone deep erosion. The irruption of the quartz diorite was slow and gradual, showing no evidence of eataclastic movement, or of form in having thrust aside the intm ded rocks. Tn

fact, the process was so quict that detached portions of the sedi-

tintin

TTED ELEY MINING DISTRICT? ORE DEPOSt;

mentary rocks in the igneous still preserve their strike gq conformity with the rest of the beds that have not becn iatricded these roeks, The gubbro intrusion, however, Was not L

aetion, for it has frequently formed a breeeiated contact ith 4 intruded sediments,

It has been very ditieult to determine whether the tilting aud deformation of the strata which is now seen in the sediment rocks happened before the intrusion of the diorite-yabbro complex, or w' other it was later. The evidence at times might point to a tin of tilting later than the diorite-zabbro intrusion, beeause, in a great many instances, the sheets of porphyry which emanated from the main musses and penetrated along the bedding planes of the sei ments, have been ineluded in the folding. This, however, might ulso have happened after the tilting, and the sheets may have simply followed the bedding planes of the Strata as the lines of least resistance, Most probably the deformation of the strata and intrusion of the diorite are genetically connected with eaeh other. In relation to the eranodiorite, there jis no doubt) that the strata were tilted to their preset.. attitude before the erosion of this rock, so thae we have a limit, at least in this direction, to thy time in which the tilting might have occurred.

The formation of the primary ore deposits is attributed to the period following the intrusion of the gabbro, and as a last result of this intrusion alse, a great many lamprophyre dikes were formed,

The next great event in the geological history of the district js the irruption of the granodiorite, in the form of a great batholith. This appears to have acted very quietly, and without materially disturbing the intruded rocks. It was accompanied by some contact iictamorphisin, but by apparently little mineralization. Aplite and quartz porphyry dikes are also connected with this irruption.

The last event recorded by the formation of rocks is the intrusion cf some rhyolite and andesite dikes which cut the granodiorite. This event concludes the igneous history, and though there is nothing to mark the time at this point, it is probable that it would bring us well into Tertiary times at a time when great surface Hows of a basaltie nature were taking place in certain portions of the adjoining country,

Deformation of the rocks by faulting has oeeurred at diferent

periods, but no definite statement ean be made that faults with a

certain strike belong to a fixed period of time. Tt is certain that

124 Geological Survey, Canada

the greatest and most epparent faults are later than the intrusion of the quartz diovit None are known to oceur in the neighbourheed of granediorite, and so the relation to this rock is unknown Kither these faults have accompanied the intrusion of the grano diorite batholith, or else they are conneeted with the orogenie move ments invelved in the Caseade uplift. The nature of the faults is euch that they may be referred to either period of time. It is certain, however, that they were of such recent date that, to a limited extent,

the topovraphic ¢ xpression of these faults is still preserved,

Claciation And Development Of Present Topograpily,

'The general uniformity of level of the higher points of the Interior Plateau region is a well known fact, and the area under discussion is a part of that plateau region.. The development of the present topography of the upper levels of the region is supposed by Dawson to be due to erosion taking place throughout Eocene times, following an uplift at the close of the Cretaceous.! Chiefly because no deposits referable to the Eocene have been found in this part of the Cordillera it is assumed that this was a time of denudation. At the same time a stability of elevation prevailed long enough throughout this period of denudation to establish conditions of well marked peneplanation over the plateau. This erosion period determined the summit levels of the plateau and developed on them the rounded outline of a mature topography. Dawson concludes that the baselevel which obtained at the close of the Eocene period stood 2,000 or 3,000 feet lower in relation to the sea than it dees now. In the Hedley area the 4,000 ft. contour line approximately marks a distinet change in topography, and it is possible that this line represents the old Eocene base-level in that region. 'Traces of the old erosion period are still to be found in the broadly flaring valleys of the creeks, above the 4,000 ft. contour line; while below this is a totally different kind of topography referable to a different and later period of erosion, and it is not likely that the old Eocene erosion cycle could ever have acted below this

Minor local disturbances of elevation and depression oeeurring throughout the Oligocene and Miocene prviods in other portions of

the Cordillera are not recorded in the Hedley area.

iG, M. Dawson. Bull. G, S. A., Vol. 12, 1961, p. 89

DisrRied aor ia

The Caseade uplift of Pliscene times ippears to hav i tive in this region in ruising the whole of the land surfa ing the streams, and thus instituting a new evel f eros revival of drainaye is responsible to a very large exeent fort ful appearance of the topography below the 4,000 fr. aT t it has been somewhat masked in the main valley below by tion,

What determine he position of the streams in the fi p not known, and car be conjectured, In the ease of tho Sin

ameen valley no @ata are at hand, and we infer from the wa which it euts across the Okanagan range oo mountain wit etm heve oceupied its present bed prior to Plios times, when the uplift took place, and it is, therefore, an antecedent stream,

In the case of Eighteenmile ereck, there j parent 1 ion between the course of the stream, and the strip of the sedinu rocks through which it cuts.

The intimate relation of certain stream courses to faults, already been pointed out. The most king instanee of this is tl case of Twentymile creek, which follows the course of tha creat

Bradshaw fault for a couple of miles before entering the Similkammwen

river. Examples of this are also seen in some of the tributaries of Twentymile creek, which follow fault lines that are not in con formity with the trend of the Bradshaw fault.

The tributary streams of the Similkameen river are still ver aetive in erosion, and have much to do to develop a thorough! graded course from headwaters to the Similkameen valley. These are tending to destroy all evidence of glaciation in their own valley-, while the Similkameen valley itself still preserves the characteristic shape induced by this glaciation.

One of the last geological events recorded in the history of this region is that of glaciation. This has left many records of its presence in the present topography. On the upper levels its action has not been so marked as in the Similkameen valley, and as before stated, this is accounted for by the supposition that glacial ice covered the upper levels for a relatively shorter period of time than the valleys, while the depth of ice was also thinner, and so erosion

iker. Tn these upper levels the principal record of the ing of glacial drift, and the presence

tion has had a mueh greater

Le GEOLOGICAL SURVEY, CANADA

'uence on the topographic form. The broadening of the valley bottom, rounding of projecting shoulders, and to some extent, the formation of hanging valleys are all expressions in the topography of ciation.

The great Cordilleran glacier at its height covered all the summits in the Hedley quadrangle, as well as the adjoining country during the glacial period. Some of the higher points in the Okanagan range which were ascended, showed the ice cap to have covered them, Lut none were much more than 7,000 feet above sea-level; so that while we know that the upper limit of the ice was above this level, no data could be obtained in this region to show how far above. Evidence obtained by Dr. Daly in adjacent regions fixes the upper limit of the ice cap at about 7,500 feet, and this coincides with the results of investigations on the south side of the boundary line.! It has been established by these observers that the Quaternary ice in the extreme northern part of Washington, directly south of here, and on the Canadian side, existed as a general ice sheet Covering almost the whole surface. Farther south, however, the ice shect was not general, but it oceurred rather as valley glaciers or tongues p 'd southward along these valleys from the main ice sheet? to the north.

In consequence &) the Hed district being within so short a distance of the southern limit of the general Cordilleran ice sheet, we should expect the results of this glaciation of the higher levels to show that the ice was losing its great power of erosion, and was rather depositing its load of debris. This is exactly what we do find. Grooved and striated rock exposures are very rare, and roches moutonnées are almost unknown; while on the other hand the covering of rock detritus is very widespread and heightens the effect of mature relief which the topography already had.

In the lower levels, however, erosive action has been much more pronounced, The evidence of this appears in tho characteristic forms produced by the glaciers in the erosion of the valleys. The Similkameen valley is a typical glacial valley (see Plate XV). The erosion of the valleys in contrast to the surface of the plateau, ean be better appreciated when we reckon the thickness of jee overlying

each of these places. As before stated, the maximum thickness over

1Smith, G. O.. and Calkins. U.S. G.S. Bull. 325, 1904. 2 Bailey, Willis. U.S. G. S. Bull. 10, 1887,

COs ta

"yd ge omens F

ED Mo Hetero ye

Dany

M185 p. 126

Sothern entailed aide aiiabaambad

Hedley Mining District: Ore Deposits 127

the Similkameen valley at Hedley was abou: §,160 feet, while at the Same stage it was only from 1,000 to 1,5... Set leep on the 1 p- land.

It is impossible to say for how long a period glacial cond were at their maximum, and covered the whole region, ine'u ling the Okanagan range, but it is more than likely that for a vers 7o:. siderable period the ice existed here only as valley loa moving slowly down the present grade of the Similkameen vesil-+ through the Okanagan range. This valley glacier! Russell has ca.led the Similkameen glacie:. Its source was in the Cascade 1 iiptains at the heads of the Similkameen and Tulameen rivers. and i; slowed down through the Princeton basin and eastward along the Similkameen valley to join the great Okanagan glacier. Much of the territory in and about the Princeton basin is considerably below the elevation of the gaps in the Okanagan range, and here the Similkameen glacier must have spre'! out over a wide area. .\s the glacier progressed eastward, howev.., the surface of the upland gradually rose, so that all the ice would be confined between the sides of the Similkameen valley, and as a result the speed would be accelerated, and the erosive action greatly increased. This in a great measure would account for the extreme glacial action in the main valley, in contrast to the weaker action on the uplands.

Evidence in support of the idea tof valley xlaciers—at least in the closing stages of the glacial periol—is feand in the direction of stria 'n some of the valleys. Strix were noted by the writer in 1906 in the upper portions of the Similkameen river, running north-

ward, parallel with the trend of the valley. 2Dawson observed strie in the valley of Whipshaw creek, running N 45 EE, or down the valley, and the same observer noted strie in the valley of the Similkameen river about Keremess, which had a bearing cf S 35° E again parallel to the trend th: valley.

Doubtless, during the perix4 when the ice seat covered the whole region, the direction of flow would, to a certain extent, be influenced by the trend of the valleys, but it is generally accepted that this general glaciation was in direction slightly west of south. This is borne out by the fect that glacial erraties found in the Hedley sheet are identical with rocks found in places to the north of

17. C. Russell. 20th Annual Rep. U.S. G.S. 2 Rep. of Progress, 1877-78, Geol. Survey of Canada.

128 Geological Survey, Canada

here. This, however, is almost the only evidence, for strim on the higher level, at least in the ITedley sheet, are unknown. It is likely that the topographic forms in these higher levels were only slightly influenced, and not greotly altered by the gencral glaciation, but that much of the present topography ean still be referred to the pre-Pliocene peneplanation.

White silts, of probably glacial lake origin, are found at an elevation 'of from 3,000 feet to about 3,800 feet in the upper parts of 'Lwentymile creek. Accepting the idea that these silts were deposits in lakes, their presence might be adduced as a further argument in favour of a valley glacier in the Similkameen valley. This, by damming the outlet of Twentymile creck, might have forced the water accumulated in the valley of Twentymile ereek to find an outlet northward or eastward to Okanagan valley, and later, when the level sank below the level of this outlet, to form a temporary glacial lake in which these silts were deposited.

The after effects of the glaciation are recorded in the filling of the valley bottom with deposits of gravel. These form very thick deposits, and it is believed that they belong to the period of dwindling of the glaciers, when the streams were swollen by the melting of the ice, and laden with morainal detritus. This detritus was deposited along the course of the stream, and since the final disappearance of the glaciers, the present streams have been slowly cutting down through this deposit of gravel, successive stages of erosion being marked by the formation of benches at different levels,

Summary Of Geologic History.

Palxozoic—

Deposition of the Cache Creek sediments—limestone, quartzite, and argillite -in a sea in which voleanic materi were being lail down with the true sediments.

Mesozoic—

Regional uplift of the strata, either accompanied or closely followed by the irruption of the quartz diorite, with apophyses injected into the sedimentary rocks.

Irruption of gabbro into the diorite before the latter was

thoroughly cooled. Consequent contact metamorphism with the f

rmation of ore deposits. Fracturing and intrusion of lamprophyre dike

1 fp eeererererrryrere rereneereeweryeeper ree srererestrnrer parece qneemere epee

Hwedpley Mining Districy

Tertiary—

Post-Luramie uplift aud deformation.

Irruption of granodiovite, wecoinpanied by aplite an dikes. Contact metamorphisia and slight mineralizatiog. on a large seale probably accompanied the granodior't jry

Intrusion of andesite dikes.

Formation of Eocene peneplain.

Uplift of Caseade mountains and Tnterior Plateau in PH times.

erosion period. Quaternary—

Glacial period.

Deposition of stream gravels,

150 Geological Survey, Canada

Chapter V. Economic Geology.

General Character Of The Ore Depostps,

All the ore deposits of the district thet have up to the present been worked contain gold as the principal valuable metal, and only gold has been extracted from them. In one or two isolated places, ores wf cupper—which are as a rule sparingly disseminate 1 throughs all the deposits—ave concentrated to such an extent that a small output of this ore might be brought about; but it is not likely that, within the limits of this area, the mining of copper ores will ever become an important industry. Up to the present, uo extraction of copper, or shipment of its ores, has taken place. These two metals oceur in the same deposits, or the same kind of deposits. There is also a genetic connexion between the origin of the gold aml that of the copper—that is to suy, both of these metals occur in deposits of contact metamorphie origin, so that the discussion of one must include the other.

At the close of the year 199s, reduction of the ITedley ores had been carried on for about four and a half years, and the annual production of gold has been each year in the neigubourhood of $500,000 in value. No copper has yet been recovered, except perhaps as a by-product of the smelting of the gold ores. At and near the surface, much of the gold occurred free, and was visible in the native form, but with increasing depth its recovery became more difficult, on account of a more intimate association with the sulpharsenide arsenopyrite. This is economically the most important mineral with which the gold is associated.

The occurrence, so far as at present known, takes only one form. This form is that of irregular, ill-defined bodies, of by no means uniform gold content, lying in limestone which has been altered by contact with diorite or gabbro intrusives. The tore minerals which ceeur in these bodies are arsenopyrite, pyrrhotite, chalcopyrite, pyrite, anid zine-blende, occurring in relative amount in the order

named.

HEDLEY MINING DIS1 RICT? ORE DEPOsIts 131

Although the rocks of the area are seamed with faults, fissures,

and dikes, none of the workable ore deposits are known ti

) OCcCur as lodes or fissure veins. Even where fissures occur in cont

1exion with the ore bodies they are generally barren of gold values, a: scarcely, or not at all mineralized by sulphides, a fact

ul ars which proves that this fissuring undoubtedly took place at a later period thy formation of the ore deposite. This is rather a striking feature, and

places the formation of the ore bodies far back in the geological

history of the region. A brief study of the conditions of thes bodies as they exist in the field j sufficient to bring out one

prominent fact. All of the kn

n deposits of workable size are intinately associated with diorite or gabbro stocks, or apophyses from these stocks. More often, and it might be said, as a rule, hey are wssociated with the apophyses, but at no great distance from the

stocks, and moreover, they oceur only in the sedimentary rock

which have been intruded by these apophyses, and not in the ign rocks, Although not many different ore bodies are known or worked, yet those that are, show beyond any doubt, in the author's

opinion, that there is a genetic connexion between the gabbro in trusives, particularly, and the ore deposits.

From their similarity of form and identity of origin it is only to be expected that the accompanying gangue minerals would b:

very much alike in chemical composition. They are always tho-

which have universally been found in deposits of contact metamor-

phie origin, where igneous rocks jaye been intruded into rocks which

are eminently of a caleareous nature, that is to say, the silicates of

line, garnet, epidote, 0' side, and tremolite. In lesser amount, where the alteration has perhaps not been so extreme, caleite anid quartz form the gangue minerals, and, in extreme cases of altera

a small amount of axinite is present.

For a region that has produced such valuable ove boi 'he Hedley district exhibits little surface evidence of its

'alth, and this in spite of the many and good exposures of the

untry rocks. The voleanie rocks of the Red mountain contain abundant disseminated sulphides, which on oxidation impart a rusty stain to the rocks. So far as known, however, no deposits of value cecur within these discoloured rocks. Contacts of the igneous rocks with the sedimentary, where pyrrhotite has been abundantls developed, also show a strong discoloration on the oxidation of the

pyrrhotite; but the presence of this mineral is never a criterion of 9185 —9}

Geological Survey, Canada

high gold values, and generally indicates low values. dt is rather the unostentatious development of much arscnopyrite on these con- Hicts, decompanied by a considerable amount of metasomatism, thet his proved to be productive of the best ore de posits. The arsenopyrite is not ve ry readily oxidized, and this, coupled with the reeent elaciation which the whole region has undergone, wives an ore within a few feet of the surface, which is very little ditferent from that 200 feet down, where the ore is certainly in its unoxidiz> 1 condition. The outcrop of an ore body, however, is often marked by a thin mantle of limonite underneath the soil, bat this doas hot run very far on the downward slope, and soon disappears altogether, It has been the experience in w ashing this red dirt that a great number of very fine particles of gold are obtained in the pan, but never any nuggets of even moderately large size. It is charactcristic of all the ore bodies discovered that the gold is disseminated through the gangue, always in very fine particles. At times the outcrop is not covered by any mantle of limonite, and the ore body shows only a very slight oxidation 'on the surface. This oxidation might extend down for 8 or 10 feet, but more often at that depth there is little or no evidence of it, and the sulphides are there in their primary state. As a result of the shallowness of oxidation, or the lack of it altogether, there is no zone of enriched sulphates, and the tenor of the ore within a few feet of the surface is generally that of the ore at the greatest depth yet reached. In certain instances, where conditions have been favourable, there is evidence that there has been a leaching downward of the gold content, and concentration in pockets or troughs, but in these eases the gold alone

have moved, while the associated sulphides have been

appears to weathered away and not transported downward. In some of the deposits, the dip of the ore body is too slight to make this factor of downward enrichment important, but even in this ease there is some evidence cf it on the foot-wall. It may be taken, howaver, as a general rule, that there has been some leaching of the gold from the upper part of the deposit, with an increase in value downward to a certain point. How far down this point may be cannot be definitely determined until other deposits are exploited.

(mn account of the irregularity with which the gold values are distributed through the deposits—being hich in certain spots, and almost wanting in others, often too, without anv apparent reason— it would he unsafe, from a few dozen assays, to attempt to give an

HEDLEY MINING DISTRICT: ORE DELO Lis 138

estimate of the average value of the ores throughout thy listriet Samples selected at random from the ore bodies of the Su id and Nickel Plate mines are no criterion of the average values these ore bodies, for one often gets enormously high values, often values that are much below the grade which it would pay to work. It is only by tuking the total amount of gold obtained after a mill run of a month or a year, when hundreds of tons have be i treated, that a correct estimate is obtained. The published statement of the Daly Reduetion Company for the year 1907 vives an average ot almost $15 to the ton for 35,000 tons of ore milled. It is certain that in the early stages of mining, when surface ores were more largely used, the average value must have gone slightly above this figure. It is probable also, that where greater depth is attained, the min

owners of the region will be faced by a slight lowering of the grade.

which will also be accompanied by greater difficulty of treatment. Thorough tests have not everywhere been made of the ore bodies of the district, but sufficient has been done to demonstrate that there are large quantities of low grade ore, giving a gold value about equal to the present cost of treatment. With improved methods of treatment, and better transportation facilities, much of this ore could be utilized,

Distribution,

The productive portion of the Hedley district is av the present time confined to the region lying near the top ef the Niekel Plate mountain, on its eastern slope. Here are located the two most in portant properties in the district—the Niekel Plate and Sunnyside mines—and these two mines have so far produced all the ore mined in the whole district. Ore deposits recently discovered, and now Leing prospected, are located in certain portions of the eastern slope of Twentymile creck, and it is strongly probable that some of these will turn out to be of economie value. If there are others inside the limits of this district they have not yet proved to be of sufficient importance to attract capital for their dev elopment.

If we inelude with the proven ore bodies those prospects that give the greatest promise of productiveness, we find that they all lie in the central and northern part of the area, and within a radius of one mile from Climax bluff. A circle, central at Climax bluff, with a rains of one mile, would cover all of the known workable ore

bodies, as well as those prospects which at present look most promis-

Geological Burve Y, Canada

Mig. It is not meant that that cirele will cover the limit ot produetiveness for all time, because ore bodies may later be found outside it, and undoubtedly much mineralization is now known to oceur vutside this limit. As regards the geological distribution of thes cre bodies, it appears that they are largely confined to one of the cour divisions already outlined of the sedimentary rocks. No important ore bodies have yet been discovered in the Redtop, Red Mountain, o- Aberdeen formations. The lowest member of the Nickel Plate formation—namely, the Sunnyside limestone—is a missive blue limestone, which has not so far proved productive, except in its uppermost portion, The remaining portion of this formation, above the Sunnytide limestone, is undoubtedly the best of the whole sedimentary series, and contains all the known ore-bodies, as well as the most promising prospects. This part of the Nickel Plate formation eontains much limestone, as well as some quartzite bands, and the association of these two kinds of rocks seems to have been the most favourable for the deposition of ore bodies, henee it is of special importance,

The mere association of the Nickel Plate formation ith rocks of later ig.:ous origin is not suflicient to determine the location of

an ore body. Another factor js necessary, and so far as present

knowledge goes, this factor is the presence of a certain kind of igneous rock. The influence of the batholithie mass of granodiorite,

much as might be expected of it from its size and generally more

acid composition, is relatively unimportant oa the formation of ore bodies. The diorite is less in quantity and areal distribution, but

its influence is stronger, The most important igneous rock, however,

and one from which the least should be expected on account of its

more basic composition, is the gabbro. This in virtually every case

een the most active mineralizer, and whose history is bound up with that of the ore deposits. This is

is the igneous rock which has

the rock, which, in the ease of all the ore bodies of the Nickel Plate, Sunnyside, and Mound mineral claims, either forms the foot-wall or is otherwise closely associated with the ore bodies. Not only here, but in other portions of the district where dikes or apophyses from the gabbro ma's have been thrust into the sedimentary rocks, it w noticed that there was a notable increase in thy

as gold values obtained, over those generally found on other contacts. Whether any general rile ean be deduced from this remains to be proved. At the present time it is more than a mere coincidence. Another point in this

HEDLEY MINING DISTRICTS OLR DEPOSTLs

connexion, but one which has its counterpart in pany oth mining distriets, is that the best ore deposits are not found immediate vicinity of the main stocks of gabbro, but ar generally at some distance from these stocks, though on dik ipophyses which have been derived from them. If the sour the gold-bearing solutions were in the stoeks of gabbro, these <0! tions seem to have travelled some distance before the gold was [iI ated and deposited from them in the country reeks, Furthes d

cussion of this, however, will be deferred to a later section.

MINERALOGY, LIsT OF MINERALS.

For convenience of reference, the names of the principal mineral species found in the ore bodies of the Hedley district are assembled in the following list. Other minerals have been found inside the district, but only those are mentioned which are known to be more or less closely associated with the ores, The list also contains cer: tain elements the presence of which is known from assay, but the exact chemical combination of which with other elements is not known.

There are in all 28 species :—

Gold. Magnetite. Silver. Limonite, Platinum. Calcite, Nickel, Feldspars. Cobalt. Pyroxene, Tetradymite. Wollastonite. Pyrite. Amphibole. Arsenopyrite. Garnet. Molybdenite. Epidote. Galena, Axinite. Chaleopyrite. Apatite, Sphalerite. Nericite. Pyrrhotite. Chlorite, quartz. Erythrite,

Gold.—This is the most important minera! in the region, from an economic point of view, and for the recovery of this all the mines

and prospects are being worked. It occurs here in two forms—in its

primary state in the ore bodies, and in a secondary state in detrital deposits. The fact that placer gold was found in the gravel deposits of the Similkameen ri-er, and some of its tributaries, first attracted

the miner to this region. The richest of these placer deposits were

low POLO. SURVEY, SNADA

found higher up the rive Lacat ld is known to eecur in limited quantity in all parte of the Sir urseen river, No placer deposits How found inside the limits of the Helle listrict that are rich

enough to work In the drift derived from the decomposition of the ore bodies, is found in very fine grains, and this ean be followed for a very short distance on the slope below the euterop of the ore bodies. It

cecurs ina dark red dirt, usually covered by other drift which eom-

jHetely conceals it,

In the ore bodies themselves, gold j only visible in the roek in

the surface ; Below thie, while the value of the ore may not

ive decreas much, gold ean rarely be seen, In this surface zone

geld ean quently be seen in a trangue of sulphides and lime

si tes. The particles are small, but can easily be detected without

the len It seen to Le associated either with arsenopyrite

or ti Nhe latter is only sparingly disseminated through

the 4 t wheres cole, it is generally found to be

rold ' ecur with arsenepyrite. It becomes visible

int the f ter oxidation of tho arsenopyrite in

hich it was t rem us an insoluble residue, while the

chopyrite ¥ arned away. What the exact nature of the com-

bination of the gold and arsenopyrite was in the primars is not

known, but it dees not appear to have oceurred as ately rite Jt is

nore likely that it may lave been intimately mixe tye +h pyrite, and in its cleavage planes, or else it is in ict: in the arsenopyrite. The great diffleulty met wit'

the gold in the stamp mill, seems to point to the actual combination of the gold with the arsenop

The visible gold that has resulted from the J! arsenopyrite is not ervstalline, but is very ragged, wi rm jccting points. It has a dull rusty tarnish, but is quite i en freshly cut.

The surface ores lend themselves very readily to reduction hy amalgamation, but in the ores below the influence of surface alteration the treatment becomes more difficult. and only a very small per cent of the total value is obtained on the amalgamating plates.

Resides the arsenopyrite, gold to a limited amount is known te oceur with the other sulphides of the ore bodies. Attempts, however, to prove the relative amount associated with each sulphide were not

seaibidnsstiuabhieureesnaeseseer ee

j e

sucerssful, All that was aseertained ft ti te

greatest amount of gold is with the areetious rite, and a proportion with the others. It is aleo determined that amounts of arsenopy rite not ea msifterm values, but that + values vary thre veh hundreds of dollers to the to The an wold associated with arsenopyrite, hotete, sphalerite copyrite, as far as the tests were ¢ ed, will be found unde

of these minerals,

In the primary ores, the gold values vary considerably. Or the average value of &14 to the ton are being mined on the Sunn side and Nickel Plate mines, but this ealue is the result of a careful selection of ores of a higher grade, mixed with those of Jow to make a uniform product from month to month. It is certain that there are large quantities of ore in the distriet which will give from #5 to &7 to the ton, and this, with the present cost of treaty and lack of transportation facilities, might only give a bare me-vin of profit, even in the case of the larger figure, for the prese of extraction must amount to almost #6 to the ton.

The fineness of the gold occurring free in Hedley district

heen determined, and no estimate of it can be given.

Silver.—No native silver is known to occur within the Iedk area, though it is reported only a short distanee outside, Ass of virtually all the Tedley ores, however, give a sinall fraction of an cunce of silver per ton; but higher values are obtained in thi deposits which lie in massive limestone, where the silver prob occurs in association with galena. It is rarely, however, in suf

quantity to make it important in increasing the value of ore.

Platinum.—-In a personal communication to the author from Mr. F. A. Ross, manager of the Daly Reduction Co., th presence of platinum was referred to. Mr, Ross says that in the process of the clean-up, at the end of a month's run of the stamp mill, an unusual deposit was noticed on one of the plates, close to the lip of the mortar. sample of this, about one pound in weight, was collected and submitted to the chemist for analysis, who reported it to vield about 0.5 per cent platinum. It was suspected that the platinum cecurred, not as the native metal, but as the arsenide sperrylite.

38 Geological Survey, Canada

Vickel.—-The presence of this element is known in the ores of this district, and it was obtained by assay from pyrrhotite concentrates from the Sunnyside mine. The exact nature of its oceurrence, however, is unknown. An amount of 0-19 per cent of nickel

was obtained by assay of the pyrrhotite concentrates.

Cobalt.—Pyrrhotite conecntrates also gave on assay a trace of cobalt. The presence of this mineral was also suspected in combination with the arsenopyrite, making the mineral species danaite. But it has not been actually determined as such, though the oceurrence of hydrous arsenate—erythrite-—on the outerop of the Nickel Plate ore body—lends weight to this suspicion.

Tetradymile (Bi,(TeS),).—Tetradymite is found sparingly in the upper parts of the Nickel Plate mine, and generally near the surface. It occurs in dark bluish crystals, which are foliated and soft, and have a bright steel grey metallic lustre on the fresh surface. This mineral was identitied in a sample of contact metamorphic rock by Prof. C. H. Warren. It oceurs in the massive altered limestone, which consists of garnet and epidote with much arsenopyrite. It is very often found in association with free gold, and specimens ef the ore show crystals of tetradymite enclosing small particles of native gold. It has apparently no connexion with any fissures, but may be the result of secondary alteration near the surface, as it has not yet been identified in the deeper part of the mine. On the other hand, the minerals with which it is associated—namely, garnet, epidote, and arsenopyrite—show little or no evidence of surface alteratien, and there is a strong possibility that this telluride may be a primary constituent of the contact metamorphic rock. formed contemporaneously with the other eontact metamorphic minerals. This, apparently, is the only one of the tellurides which has up to the present been identified in contact metamorphic deposits. 'Prof. Warren in testing a small portion of the mineral got a reaction for lead, which et first led him to suspect uagvagite, but further tests gave astrong bismuth coloration, which, with the general appearance and erystallographie form, proved the mineral could only be a tetrady-

mite, which carries some lead.

"W. H. Weed, geology and ore depo-its of Elkhorn quadrangle; 22nd Annual Report U.S. G.'S., Part IT.

Hedley Mining District! Ore Deposits 139

Pyrite (FeS,).—Pyrite is not as abundant as either arsen pv or pyrrhotite, and, because it has not been found as a general rule in association with the ore deposits, has not been as closely studied as the other sulphides. Its occurrence is not general amone the rocks of the area, but its distribution is localized in certain isolated areas. In these areas, however, it becomes quite abundant. On the 3ulldog mineral claim it is abundantly developed in the contact metamorphic zone of the sedimentary rocks. The contact metamerphism has here been produced by the intrusion of a gabbro porphyry, and the pyrite appears in massive form, in bunches scatter through the mass of the lime silieate rock. It also follows we defined lines, as if filling small fissures in the altered sediments It is also found very sparingly disseminated through the igneou tock. It is generally of a very pale yellow colour, and as a rate occurs in granular masses, without any tendency to erystallographic

outline,

Arsenopyrite (FeAsS).—Arsenopyrite is the commonest and most widespread sulphide in the district. It is found in all the igneourocks, and their dike equivalents, and also in the sedimentary rocks where cut by these igneous rocks. In the plutonie rocks it is always well crystallized, and is sparingly disseminated through them. It was observed more abundantly in narrow cracks in the granodiorite,

where it appears in a gangue of white quartz, and it appears in the

same way in the diorite. In the dike equivalents of these plutonic rocks, and particularly of the diorite and gabbro, it becomes much more abundant, and appears always in well) formed individuals, apparently the first to crystallize. It is also an original constituent in the voleanic rocks of the Red Mountain formation. Tt is most abundant, however, in the contact metamorphie zone of the sedimentary rocks, where these have been intruded by the dike forms of the dioritie and gabbroid rocks. Here it occurs as disseminate individuals in well formed erystals, or else in more or less well-defined bands when the crystallization is less perfect. It appears to have boon formed in this case simultaneously with the garnet, epidote, and other contact metamorphic minerals, and is associated generally with pyrrhotite, less frequently with chaleopyrite and blende, There ean be ne doubt that the arsenopyrite of the eontaet metamorphic r

heen derived from the igneous rocks, for thera is no signa of

presence in the unaltered sediments, and the transfer from the

140 Geologmbal Survey, Canada

to the other was effected immediately after the intrusioa, aad crystalization took place simultaneously or even slightly before the other contact metamorphic minerals. A later generation of arsenopyrite accompanies the crystallized arsenopyrite, and this appears in more or less well-defined lines roughly parallel to each other and showing a erystallization much less pertect than the above. This form is probably due to eruptive after-actions, following the igneous intrusion either before complete reerystallization or shortly aiter it. There is a slight difference in colour between these two kinds, the erystallized variety being white in colour, while the massive form has a very slight bluish tinge. When crystallized, the arsenopyrite is very often twinned, the twinning lines appearing Qs striations on the faces ef the crystal. The arsenopyrite is most important, on account of its association with the gold. It has been definitely proved that gold, rarely, if ever, occurs in payable amounts, unless arsenopyrite is present in the ore in considerable quantity; hut it has also been demonstrated that all deposits of arse~ opyrite in this district n- 1ot necessarily contain gold in sucient quantity to pay for .cking. The massive form is more often am indication of good gold values than the well evvstallized form. On

aecount, however, of the patehy nature of the distribution of the gold values, concentrates of pure arsenopyrite give very variable amounts of gold on assay. Absolutely clean arscnopyrite taken from a part of the ore body which was known to be rich, gave results of 12-38 ounees im gold and 0-78 ounces in silver per tor, also 8-36 eunecs in gold and 0.06 ounees in silver. Another assay of pure arsenopyrite, which was taken from another part of the ore body, also being mined as rich ore, gave only 0-30 ounces in gold and 6.39 eunces in silver. Experiments of this nature simply serve to confirm the findings of the mine operator: that the gold values are in spots, and that iv is impossible to tell, except from assay, what results arsenopyrite ore will give in gold values.

Molybdenite (MoS.).—Molvybdenite was noticed in only one locality in place, nemcly, on the northeastern slope of Twentymile creek, about half a mile below the dam. It is here found in small

fine scales of a bluish grey colour and metallie lustre, sparingly

disseminated throughout the quartz diorite, near the contact of a rhyolite dike. It was also found in float of the same kind of reek in the lower part of Windfall cafion.

Hedley Minin

Galena (PbS).—Galena

though carefully looked for, was not seen in any of tl

that are now undergoing development. It has, however, been 1

fvom a locelity in Climax

nile creek.

Chaleopyrite (Cukes ).-

rence in many parts of the district, but is contined to the sedimentar

rocks and to the contact metamorphic zone. of

G ISTRICT: ORE DEPOsIts 111 is of very rare occurrence indeed. a! he ore 4 port

cafion, on the Tw

eastern slope ot

Chalcopyrite is of very common oecur-

t! wk

t

ese or . 3

found in small amounts in all of the Sunnyside and Nickel Plats

nine Workings, and in many ant, however, in the massive claim, on the eastern slope to be in sufficient quantity never in a well erystallized tlways in small irregular through the altered sedime1 horse m'neral claims, these

persistent than in other plac

ally be measured in inches.

generally accompanies arsenopyrite, and in that case is seen to

iiong the borders of arsenoy

ound in the interstices betw

other mineral claims. It is most abundblue limestone of the Warhorse mineral of Twentymile creek, where it appears to be mined as an ore of copper. It is form, but is always massive. It appears and not continuous veinlets, running On the Bulldog and War-

veinlets are larger in width and more

itary rocks.

es, but even here their length ean gener-

In the Nickel Plate ores chalcopyrite lie yrite crystals. In other cases, also, it is

een the crystals of arsenopyrite, and mas

on that account be one of the later sulphides to be formed in the ores.

the though widely disse1 trated to mak

where

yt i mention

ae Chaim

ion ' iN 1 ease

coprrite, it eurs al

a profitable ore for the extraction of copper. Ch

ned above—viz., the Warhorse mineral!

ninated, it is never sufficiently concen

ial-

one, is never associated with high values

in gold. Some chaleop) rite ore obtained from the Warkorse mineral claim was coneentrated on the Wilfley table and ther passed through the Wetherill magnetie separator to clean out the magnetic material. The conecratrate was then assayed, and gave a result of 0-20 oune of gold per ton. with 2-80 ounces in silver. This shows the amount

gold associated h the echaleopyrite to be ver t stiver content was mueh ther than that obtained 1

her sulphides.

"phalervite (Zn sphaierite or z blemde ha ribution and is only found few isolated places. Tn these lowever, it is impor heing a ited th high gold y

amo

112 Geological Survey, Canada

No. 2 workings, and more sparingly in the Nickel Plate mine. It was also noted in one or two places on the eastern slove of tha canon of Twentyimile creek, In all of these cases it occurs in the sedimentary rucks in the contact metamorphic zone, and not far from the igneous coutact. In the Sunnyside mine it appears in welldetined bands close to the igneous feot-wall, and in general parallel tu this feot-wall. It is here associated with arsenopyrite and pyrrhotite, and sume chalcopyrite, and appears to be a later product of erystallization than at Jeast the two first mentioned minerals. It also occurs both at this place and in the Nickel Plate mine in well crystallized individuals, disseminated through a gangue of lime silicate minerals. It is generally a very black metallic mineral, aud from its appearance contains a high percentage of iron. Less frequently its lustre is a dark reddish brown. Attempts to obtain by separation a clean concentrate of zine blende were not successful, on account of the s.nall amount of material that was available. Prof. Gwillim, of Kingston School of Mines, atter passing some blende ore through SO mesh screens, ran it over the Wiltley table to extract the heavier arsenopyriie; the blende concentrate obtained was then deprived ef its more strongly magnetic material, and the result was a product which contained almost entirely blende and gangue. This was assayed, giving a result of 11-38 ounces in gold and 1-20 ounces in silver per ton. The result of this test was merely sutiicient to prove that fairly high values are associated with the blende, but it did not

prove that these values were in th blende alone.

Purrhotite (Fe,,S,,).—Next to arsenopyrite, pyrrhotite is the most

common sulphide in the whole district, and is found in all parts of

the area. It is, however, not imyortant in an economic sense, as it

12 never direetly associated with gold values, unless arsenopyrite is present at the same time. It is very abundant in the voleanie rocks of the Red Mountain fo nation, where it appears disseminated through the mass of the rocx. It is still more abundant, however, on the contact of the more basie igneous rocks with the older sedimentary rocks. It appears here in the sedimentary rocks in the contact metamorphie zone. As a contact metamorphie product, it is abundantly developed on the Warhorse mineral claim, where it appears in association with chalcopyrite in the limestone. It is much less abundant in the Nickel Plate ores, where the gangue consists en

tirely of lime silicates, than in all the Sunnyside workings, where

Hedley Mining District! Ore Deposits 143

lime silicates are not so abundantly developed, and lime carbonates are in greater proportion, Pyrrhotite never forms good crystals like arsenopyrite, though it appears to be of contemporaneous Ovigin in the ore deposits. Instead, it appears in massive form in irregular #reas, or in small particles disseminate through the mass of the contact rock. Several analyses of pure pyrrhotite, separated by yiavnetic concentration from some of the ore being mined fron the different Sunnyside workings, guve a very constant value for gold ecutent, and also for the silver. It was found that the amount of gold in this pyrrhotite was on an average 0-065 ounces to the ton, or $1.50. Values as high as $1.60 to the ton have been obtained by the Daly Reduction Company's chemist, but from $1.30 to $1.60 is a very narrow range indeed, and proves the gold content to be almost constant. The silver value of pure pyrrhotite was also found to be very constant at about 0-06 of an ounce to the ton. Analyses also showed that a trace of cobalt, and 0-19 per cent of nickel, were present in the pure pyrrhotite.

Wuarlz (SiO,).—This mineral is of vi ry Common occurrence, It is an important constituent of the granodiorite, the quartz diorite, and the quartzite. It oceurs in the form of chert or tine-grained varieties in the limestone beds. It oceurs, also, as chaleedonie silica in some of the siliceous or argillaceous sedimentary rocks. It is abundant in places in the contact metamorphic zone of these sediments as a secondary mineral, In such eases, it often forms large prismatic crystals, which hold inclusions of ealcite, epidote, arsenopyrite, and other minerals, and in the weathering of the caleite and associated minerals, forms an interlocking net-work of large hexagonal erystals. In the fresh unweathered rock, the formation of these large quartz erystals in the calcite gives an appearance of breeciation to the whole rock. This character is wel! shown

in the workings of Sunnyside No. 4, and in the Exel, Inge tunnel

As a secondary mineral in the ore bodies, it occurs in irregular ; re; filling interstices, or in small fractures with somo calcite. It. is

found, also, in small fractures traversing the granodicrite and quartz

diorite bodies. As an alteration product it appears in the thin see-

tion as filling small fractures in some of the garnet of the Nickel Plate ore hody. Because veins with u width of more than a fract an inch sre virtually unknown in the d strict, quartz no

opportunity to form 1 fissure filline of any but very small size

Geological Survey, Canada

Its greatest development in this form is seen in the contact phase of the granodiorite, where the rock is eut by small fractures which

are filled with white quartz.

Limonite (2 Fe.04+31,0).—Limonite is common in the zone ot

pirface oxidation, and is characterized by a yellowish brown appearunee, It is seen in abundance in the surface gravels on the Sunnyside mine, where it forms the cementing material which unites the boulders and pebbles to form a coarse conglomerate. It has here becn derived by oxidation from the iron sulphides and other iron bearing minerals higher up the slope of the hill. It is present, also, in the decomposed metamorphosed limestone, though it never goes deep into the rock. Iron compounds are very abundant in the rocks of the Red Mountain formation, and by .xidation of these, limonite is formed on the surface of these rocks, wherever they appear,

Magnetile (¥e,0,).—This mineral is not abundant in this district. Tt occurs sparingly in the granodiorite, diorite, and gabbro, and their dike equivalents, but it is rare in the zone of contact metamorphism. In the more basie plutonie rocks which contain a large proportion of titanite, it may become titaniferous, or be entirely replaced by ilmenite. It also occurs sparingly in the sedimentary reeks, and the small amount noted in the contact metamorphie zone is probably not a result of the igneous intrusion, but is original in the sedimentary rock.

Caleite.—Calcite in coarse granular form constitutes much of the Stevenson limestone, and bands of the Sunnyside limestone. A great part also of the Kingston limestone is made up of coarse white granular calcite. In the contact metamorphie rocks, it is abundantly developed either alone in coarse granular masses, or along with garnet, epidote, pyroxene, and the sulphides. In the latter ease, it forms very large white rhombohedra, occurring in veins or bunches. In the ore of Sunnyside No. 4 it is abundantly developed as la white or pale greenish erystals, with well marked cleavage. erystals held Jarge inelusions of epidote, pyroxene, garnet, arsenopyrite, and pyrrhotite, and give a poikilitie strueture to the rock. As a very much later product, ecaleite oeeurs as a filling of very small fissures traversing the metamorphic rocks, also as a filling of the eracks of garnet. Again, as a secondary mineral, it was noticed

sparingly developed in the plutonie igneous rocks, and more abun-

NWEDLEY MINING DISTRICT! ORE DE POST Ts

dautly in their dike equivalents. In the diorite, where it was fo ind in one or two instances as interstitial between other minerals, it

the appearance of being a primary constituent,

Titanite (CaTiSiO,).—Titanite is an abundant accessory ¢ stituent in the thin sections of the granodiorite, diorite, and gabbre, and their dike equivalents. It also appears in the same way, in contact metamorphic rocks of sedimentary origin, and in conse ence is frequently seen in sections of the ores. Its size is microscopic, and is never seen in the hand specimen. It appears in the thia section in characteristic wedge-shaped grains, with a brownish colour and a slight pleochroism. It is most abundant, however, in the gabbroid rocks, and in the more basie facies of the dioritic rocks.

Feldspars.—Orthoclase in the plutonic rocks of the district is less abundant than plagioclase. [t is found in the granodiorite and diorite as white crystals and grains interstitial between the plagioclase and nornblende crystals. Plagioclase is abundantl. 'loped es oligoclase and andesine in the granodiorite and diorite, and as labradorite in the gabbras and lamprophyre dikes. All of those plutonic rocks are also cut by small veinlets of pink acid feldspar. In the metamorphic rocks it is present as small wedge-shaped erystals of unstriated feldspar, tilling small fissures which traverse the rocks in the neighbourhood of the igneous intrusion. As a metasomatic mineral, it is found in a limited amount in the igneous and metamorphic rocks with which the ore body of the Nickel Plate mine is associated, In large, clear, but undefined masses it replaces the constituents of the gabbro dikes forming the foot and hangingwalls of the ore body. Also, in idiomorphie well erystallized individuals, clear and free from inclusions, it replaces the pyroxene pheno erysts of these dikes, either by projecting in from the outer edges, or by developing in the interior of the pyroxene to form a mosaic of feldspar and pyroxene. There ean be no doubt in these cases of the secondary origin of the feldspar, and the variety is very much hke the adularia which is so common a product of metasomatism in the vicinity of ore deposits. If it is adularia, however, its presence is rather difficult to understand, when potash feldspars are so subordinate in quantity to the lime soda feldspars, and virtually unknown in the rocks immediately connected with the ore bodies.

Pyroxene.—This mineral, in its different forms, is one of the most abundant in the district. and is found both in the intrusive and ¢ 9185—10

id

Geological Survey, Canada

tact metamorphic rocks, As a diallage it forms about 39 per cent ot the gabbro phase of the diorite-gabbro complex. These erysta!: are large and well-developed, with a strong augitie habit, and have ® white to very pale green colour. The composition, as worked out from the chemical analysis, is given in the petrographic description of the gabbro. In the gabbro dikes associated with the ore bodies, it has suffered some metamorphism. Thin sections of these crystals show a frequent replacement by calcite. A peculiar replacement by unstriated feldspar is alse cceasionally seen. In this case, wedgeshaped erystals of feldspar project from all sides into the diallage, until the whole erystul is finally replaced by an aggregate of feldspar grains. In the contact metamorphic rocks, a pale to dark green variety of pyroxene is very abundant. and has been determined as diopside. This is a magnesia-lime silicate formed by the intrusion of igneous rock into impure limestone, by the alteration of carbonate to silicate. It is found intergrown with epidote and garnet and some of the sulphides. In the thin section it has a strong resemhlanee to epidote, but is distinguished from this mineral by a slight difference in colour, and a distinct prismatic cleavage. It generally preserves its freshness, and when altered goes to chlorite and serpentine.

Wollastontte (CaSiO,).—Wollastonite is much less abundant than nny of the other lime silicates, and like them is a preduct of contact metamorphism. It is found sparingly in the altered limestone, particularly in the Sunnyside mine. It is difficult, in the hand specimen, to separate from tremolite, on account of its fibrous structure, but in the thin section is distinguished by a mueh higher extinction angle. In colour it is white, and has a vitreous lustre, while the microscope shows it to be made wy of bundles of parallel fibres with frayed and broken ends. It is associated with garnet, epidote, and pyroxene, but is much less abundant than any of these minerals.

Amphibole—Common hornblende is an essential consists. at of the granodiorite, and of the diorites and its apophyses, ais: che lamprophyre dikes it is very abundant. A colourles variety, which analysis by Mr. R. A. A. Johnston determined to be tremolite, is common in certain portions of the metamorphosed limestone, at n reat distance from the igneous contact. It is here associated largely with garnet and some pyroxene. It appears in the ore of

ERT IRR TUR TLRS TEARRTRR- cor SEMIN "eRe eee

Co

HEDLEY MINING DISTRICT! OLE DEPOSs(tLS 14%

the Sunnyside mine, and on the Warhorse and Copper World aii

claims, and always in long tibrous aggregates of a white glistening

eclour Often it is in seat-like bundles of long slender radiant

fibres, with a normal optical behaviour.

Garnet—Garnet oceurs in this district, very abundantly developer in the metamorphosed limestones. In colour it is wine-vellow to dark reddish brown, and has a resinous lustre, It is most probal)! the variety andradite, or the lime-ire. garnet. It most commen! eecurs in the massive form. yet in many places beautiful lars dodecahedrons ean be obtained. It. is generally associatel with epidote or pyroxene in the contact me tamorphi ie, and with thes minerals it lies in distinet bands which appear t low the original bedding planes of the rock. It also a companies ealeite, and is then seen as small erystals embedded in large ecaleites. [n the thin scetions it is seen not only in well-detined bands, but it. alse appears in bunches scattered through a mass of epidote on roxene grains. Ifere it rarely shows the normal i tropie character, but more generally shows the optical anomalies peculiar to this species. This

consists of feeble to strong double refraction, with a regular zonal

structure, or concentric bands. It is frequently intergrown wit! epidote, diopside, and arsenopyrite, and sometimes holds these thre: minerals as inclusions. It is traversed by irregular eracks, and these are often filled with calcite or quartz.

The garnet is highly developed on the contaet of diorite and gabbro, and much less on the granodiorite contact. It has been the experience in this region also, that garnet has been more highly developed in the impure siliceous limestone than in the Nore wiassive and pure varieties. Tt always zecompanies the ore, and it eannot be faid that gold values seek the garnet or epidote areas in preference to any other. Not only has garnet a wide distribution among the sedimentary rocks inside the Tfedley area, but it also covers a great extent in the rocks outside it, wherever ignecus rocks have been injected into the older sedimentary rocks,

Epidote——This mineral. a silicate of lime, iron, and alumina, Appears as a secondary product in the feldspars of the diorite and gabbro and their porphyries, and also of the lamprophyres. Its principal oceurrence, however, is in the metamorphie zone of the sedimentary rocks, and, on aceount of the large amount of contact

9185 tak

148 Geological Survey, Canada

metamorphism in the district, it is very abundant. It occurs here in intimate intergrowth with garnet, pyroxene, arsenopyrite, pyrrhotite, ond chaleopyrite. Attempts to show a definite sequence in the crystallization of these minerals entirely failed, for conflicting results were obtained throughout, and an apparent sequence obtained in one case was often reversed in another, Well erystallized individuals were very rarely seen, but its characteristic habit is a massive form, which under the microscope is seen to be made of a multitude f small irregular grains. It is ditheult to separate from the pyroxene, but as a rule does not show such a good cleavage as the pyroxene. With garnet, in the Nickel Plate mine, it forms distinet bands which are conformable to the original bedding planes of the rock, It is also oceasionally seen as the filling of small fissures traversing

the contaet metamorphie rocks,

trinite.—This mineral, which is a boro-silieate of caleiam and aluminium, is found in~ several places in the central portion of the district. It occurs in the neighbourhood of Climax bluath ¢ immediate contact of the gabbro stocks, and in the workings of the Nickel Plate mine. It is not widely distributed in distance in this district, nor is it found in a variety of rocks. Its home is in the sediments in the zone of contact metamorphism, and sa rule, not far away from the eruptive rock. On the northern side Climax bluff it is found on the border of a gabbro stock in a eeciated rock, which is made up of fragments of quartzite and ied imestone, cemented by an igneous cement of soft greenish-

able rock, 'The breeciation is doubtless due to the intrusion

the gabbre, and the axinite oceurs in it in bunches from a few inches up to a foot in diameter. Also, in the Nickel Plate ore body, it appears often in segregated masses ev individual crystals scattered

through the rock in localized areas, and is here one of the products

of contact metamorpiism, induced by the intrusion of the gabbro porphyry It has echaraecteristieally a eclove-brown colour, and is always erystallized, showing the typical acute-edged erystals, with a bl 1 columnar structure.

Apeftte-—A phosphate of lime and fluorine. In connexion with he ores, apatite is not, as a rule, abundantly developed, but it was noticed in e thin section obtained from the ore of Kingston mineral claim, within a few feet of the contact th the diorite. It oeeurs

in small white ervstals of prismatie ha 1 moderately high

relief, in association with garnet, diopside, and other ecaut

morphie minerals.

Lrythrite—Hydrous cobalt arsenatee—Vhis mineral was noted sparingly in some of the ore lying about the Nickel Plate glory It is au oxidation product of some of the arseaopyrite, and appears Where the rock hus been for some tine @Xpos do to th phere. It is globular in form, or appears as an inerustution on th rock. In colour it is pink or peach red, and is very soft and

beoken down,

Sertede—What appears to be this variety of mica is Trequent reon in the thin reetions, as an alteration product of feldspar, It is, however, not so abundantly developed in this district as in mans tiining districts. The feldspars of the igneous rocks associated with the ore bodies show a greater tendeney to go over to sericite thai

those of the main bodies of plutonic rock.

Chlorite-—Chioritic minerals form rather abundantly in some ot the dike rocks which have been subject to alteration by ordina: decomposition, Chlorite, however, is rare among the minerals which

nike up the ore bodies.

CHARACTER OF DEPOSITS AND RELATION TO COUNTRY Rot Ne

Tupes.—Up to the time of completion of the tield work of this district, the number of ore deposits developed and being mined was net great. The best known of these, and that tirst worked, and now most extensively developed, is the Nickel Plate ore body. 'Lhe outcrop of this lies on the eastern slope of Nickel Plate mountain at on elevation of 5,900 fect above sea-level, or about 4,300 feet above thi bottom of the Similkameen valley. Twelve hundred fect to the southcast of this and 250 feet below it, is the northern ore body of the Sunnyside mine, commonly referred to as Sunnyside No. 4. Lying 10 feet to the south of the Jast is Sunnyside No. 3, while Sunnvside No. 2 lies 400 feet to the south of Sunnyside No. 3. A fifth ore hedy, known as Sunnyside No. 1, lies on the southern border of the Sunnyside mineral claim, but it has not yet been much explored, and its dimensions are not known. The four first mentioned are the mest important and best known ore bolies in the whole district, and from a study of these, deductions were drawn as to the nature

and eecurrenee of the ore bodies of the whole camp. Other ort

MICROCOPY RESOLUTION TEST CHART (ANSI and ISO TEST CHART No. 2)

N Co)

es wo nN

Fffeeere Ee

rrr

r fr

aE

150 Geological Survey, Canada

bodies, whose dimensions and values have not yet been thoroughly proved, are known to occur on: the Mound. Horsetly, Warhorse, Kingston, Metropolitan, and Florence mineral Cluims; but so fay as known they exhibit somewhat similar characters to the four above mentioned, and are, therefore, included in the general description and classification, These four have, themselves, characteristic features end environment which place them ull in the same type of ore body, so that no division need be made. This type may be described as containing ore bodies of roughly tabular form—without any welldetined walls—Iying in metamorphosed limestone beds, either on the direct contact of an intrusive igneous body, or within its sphere of influence. They contain gold as the principal valuable metal, and are mined for this. They are not directly connectel with any evident system of fissures, and are undoubtedly due to the igneous intrusion. They are, therefore, true contact metamorphic deposits, hut of a type unique in themselves, inasmuch as they have arsenopyrite as the principal sulphide, and have no equivalent, so far as known, in North America.

Ore and Gangue Jiinerals and their Paragenesis.—All the minerals that have any connexion with the ore deposits have been described in detail in a previous section. Many of these, however, are relatively unimportant, while there are others which are essential constituents of every ore body. Of the latter, arsenopyrite is by far the most abundant ore mineral, and is found not only in the ore deposits, but on nearly every contact of the igneous rocks with the sedimentary. It is safe to say that no shaft has been sunk or tunnel driven cn any prospect in the district which does not show mineralization to some extent by arsenopyrite,

Next in abundance, but of very much less economic importance, is pyrrhotite. This mineral is not necessarily an essential constituent of the ore bodies, and in some deposits it is wanting; but it occurs in great abundance in certain localities, especially on Red mountain, and south of the Climax eafion. Like arsenopyrite, it is found on tue contacts of the diorite-gabbro rocks with the sediments, and particularly where these sediments are strongly calcareous. Its companions are generally arsenopyrite and chalcopyrite, rarely ephalerite.

Next to arsenopyrite, chalcopyrite is perhaps the most widespread sulphide, but it occurs in such small amounts that its presence is

HEDLEY MINING DISTRICT! ORE DEPOSITS often overlooked. In the eres of the Nickel Plate and Sunnysid mines it is always present, though sparingly, and in only one or two

other places does it become abundant enough to be conspicu

Sphalerite and pyrite are relatively less abundant throughout the whole district than the three above-mentioned minerals, and their distribution is restricted to certain ore bodies on the Nick Plate mountain. Where they do occur, however, thes are of tir-t importance, and exceed in quantity all the other sulphides, except arsenopyrite. Like the others they are found in the sedimentary rocks in the contact metamorphic zone, and their origin is due t the same processes by which the others were introduced into thes rocks,

Of the various minerals associated with the ores in the capacits of gangue, calcite has undoubtedly played the most important part. It is seldom, however, that the mineral forms as 'arge a part of the ore bodies, where contact metamorphism has been most powerful, as it does in the less altered rock, where mineralization has been less active. Though it still remains in certain ore bodies more distant from the igneous rocks, it has been largely replaced in the process of contact metamorphism and mineralization by the five sulphides mentioned above, by various lime silicates, and by quartz. In ore bodies, such as the Nickel Plate ore body, where the metamorphism has been extreme, it has been entirely replaced in the body of the deposit, and is only found as a secondary mineral filling small fissures.

The replacing minerals, and those which now form the gangue of the ores, are all silicates of lime, magnesium, and iron, and the most important of these are pyroxene, epidote, garnet, and amphibole. There are a few others, and their occurrence has been deseribed in another section, but they are relatively unimportant, and their distribution is not wide. To complete the list of important gangue minerals, quartz must be added.

With the exception of the pyrite, the four principal sulphides mentioned above—namely, arsenopyrite. pyrrhotite, chalcopyrite, and sphalerite—oeeur so abundantly, and in such frequent association with each other, that there are many opportunities of studying their

found

paragenesis, or order of formation. These sulpuides are also in close association with the principal ganeue minerals, so that the

relation of each of them to these gangue minerals can readily be

152 Geological Survuy, Canada

worked out. For the study of the gangue minerals, thin sections offer the best opportunities, but for the opaque metallic minerals, polished surfaces of a hand specimen of ore give by far the most satisfactory results. In discussing this subject of paragenesis, a three-fold division suggests itself as the simplest form of treatment. These subdivisions are: (1) paragenesis of the ore minerals; (2) puragenesis of the gangue gnineralss and (3) relations of ore to gangue minerals.

(1) Among the metallic sulphides of the district, arsenopyrite always has the best developed erystal outlines, while pyrrhotite, chaleopyrite, and sphalerite rarely show any tendeney to erystallographic form. Where arsenopyrite and chaleopyrite occur together, as they so generally do, arsenopyrite formas large, well developed crystals, while the chalcopyrite lies in a thin streak around its outer edges. It does not appear as if the chaleopyrite were occupying a small fracture plane along the edge of the arsenopyrite, but rather as if in crystallizing from solution the chalcopyrite was forced to take that position by the greater crystallizing power of the arsenopyrite. They would, therefore, Le of virtually contemporaneous o: igin. If the chalcopyrite were later, and filled a fracture, we should expect, where arsenopyrite is so abundant, that occasionally the fracture might cut across the arsenopyrite crystals, and the chalcopyrite be in this; but no such occurrence was ever noted, and we are forced to the conclusion that the two minerals formed simultaneously. TM the same way, when arsenopyrite, pyrrhotite, chaleopyrite, and sphalerite occur together in the same section of a hand specimen, the arsenopyrite forms large crystals of regular outline, while the ether three are intergrown together, and fill the interstices between the arsenopyrite crystals. No fracturing is apparent, but the DY . 0- tite (See Plate XVI), chalcopyrite. and sphalerite appear to nave formed from the same solution as the arsenopyrite, and were forced to a subordinate position in the interstices, by the greater crystallizing force of the arsenopyrite. All, however, are of the same age.

In the high grade ore of the Nickel Plate mine, not far below the surface, it is highly probable that there are two generations arsenopyrite. In thin sections of this ore, two kinds of arsenopyrit: are apparent—the one the customary kind, well crystallized, and the other following well-defined lines, and without good erystallographic form. The latter is taken to he due to the same causes as the for-

Phare XVI

Polished surface of ore from Sunnyside mine, Noo 3. White areas are arsenopyrite well crystallized. Grey areas pyrrhotite, without erystallographic outline.

Dark areas ground miss of diopside and quartz

-RY MINING DISTRICTS ORE PEPOST Ts

mer, but of a slightly later date, and fills cracks which formed on

the cooling of the rock. In the same way, chalcopyrite is \epy

eceasionally seen filling minute fissures in the ore body. The

second generation of these two sulphides, however, is ineonsideralle

in proportion to the amount that is undoubtedly of pr

origin.

2) In the case of the gangue minerals, it is dite ilt to gen ral ize, for the order of crystallization whieh holds in one case will not hold in another. Calcite in all cases was the original mineral where the ore bodies now lie. In the immediate neighbourhood of the intrusives, however, the calcite has been entirely replaced, and none now remains. Where metamorphisin has not been so extreme, as in some parts of the Sunnyside mine, much cf 't vet remains as an original constituent of those minerals, but the Jarge erystals which are there formed are seen to be full of smaller erystals of garnet, grains of epidote and diopside, and the sulphide minerals, Quartz is also seen in the thin sections to be replacing the calcite. This kind of calcite, therefore, is of earlier formation than the lime silicates garnet, epidote, pyroxene, and hornblende, and also quartz and the sulphides. There is, however, another kind of calcite which is later than the above-mentioned minerals, and this is found in fissures, traversing the ore bodies, and is probably due to circulating surface waters.

Where calcite has been completely replaced, and the lime silicates formed, no definite and uniform order of crystallization can be made out. An apparent sequence in one section will he completely reversed in another, so that it appears accidental which of the four—garnet, epidote, diopside, or tremolite formed first.

Quartz is undoubtedly later than the ealcite, and frequently replaces it, without replacing the garnet and epidote which formed in it. It appears to hold a fairly constant relation to all the other gangue minerals, and is one of the last minerals to have formed. It frequently fills small fissures in the ore tidy, and often occupies cracks in the garnet crystals, so that it can only be of later origin.

(3) Although arsenopyrite has the best erystallographic form of all these minerals, both ore and gangue, it does not necessarily follow that it is to be considered as being earlier in origin. Thin sections cf arsenopyrite with this idion.orphie outline are seen under the

microscope to he full of small grains of epidote, garnet, and diop-

4 Geological Survey, Canada

side, and we infer that these minerals must have be en formed before

the arschopyrite attained that development. A rain, the borders of

the arsenopyrite ersstals show an intimate intergrowth with the

lime silicate mint rals, and polished surfaces show the arse hopyrite disseminated through a gangue of lime silicates. (See Plate XVII.) Quartz is the only one of the gangue minerals which js not

Included in the arsenonyrit . so that it is always decidedly later. i. other sulphides, pyrrhotite, chaleopyrite, and sphalerite, while never well crystallized or holding inclusions of the gangue minerals, ure seen in the polished surfaces of the ore to be intimately intergrown at least with the epidote and diopside, so that they, also, are ot Virtually simultaneous origin,

In summing up the paragenesis of all these minerals, it appears clear that calcite was the origin! mineral of the ore bodies. Some quartz was also present, as seen in the same beds where there has been no metamorphism. After the intrusion of the igneous rocks inetamorphism took place, and some material was added to form the sulphides and the lime silicates. The result of this transfer, and of the heat of the igneous intrusions, was a recrystallization, during which epidote, garnet, diopside, and tremolite were formed Simultaneously with arsenopyrite, pyrrhotite, chaleopyrite, and sphalerite. Some arscnopyrite and chaleopyrite were probably introduced slightly later as a second generation. Last of all, quartz was formed. After the rock had cooled again, and the ore bodies formed, 'i minute fracturing took place, and these fractures were filled with secondary calcite, and some quartz. In rare instances, some of these fractures contain clear unstriated feldspar as a secondary mineral, but the amount is relatively small.

Dimensions.—With the single exception of that of the Nickel Plate, the ore bodies of the district have not been explored sufficiently to give a definite idea of their general outlines. The boundaries of an ore body are detined largely by the cireumstances under which it is worked, including the cost of treatment of the ore, ete. In the case of the Nickel Plate ore body, which may be taken as typical of all, its boundaries could easily be extended to greater length, provided the cost of mining and treatment could be reduced. It is possible, however, to obtain a fairly definite idea of what at present constitutes the ore body in the Nickel Plate mine. by examining a plan of the underground workings.

Polished surface of typical Nickel Plate ore. Characteristic Nickel Plate ore showing arsenopyrite (white) disseminated through a gangue of epidote and garnet,

M185—p. 14

Pare xvi

Banded structure in polished surface of Nickel Plate ore. Nickel Plate ore showing arsenopyrite (white) disseminated through a yangue of garnet and epidote, or arranged in bands along the original bedding plane of the rock,

9185—p. 134

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Hedley Biining District: Ore Deposits 155

Following the method used by Lindgren and Ransome in descr) ing the geometrical relations of the ore bodies of -ipple creek. the dimensions of the Nickel Plate ore body are about as follows: pitch 25° W or coincident with the dip of the intrusive which acts as the foot-wall; pitch Jength $50 feet as far as: width or thickness varying from 15 to 65 fect: xreatest breadth, 125 feet. The trend of the longest diameter is roughly N sv? W,

Comparing these dimensions with the ore bodies of the Sunnvside mine, which are the only other ore bodies sutticiently developed to warrant a comparison, it is found that the pitch in the ease of the Sunnyside body varies from 30° to 0, and is dependent largely on the dip of the sedimentary rocks in which the ore bodies lie. The pitch length and the breadth are variable, but, so far as known, are less than in the Nickel Plate ore body, while the thickness does not often exceed 25 fect. A striking similarity appears in the bearing of the longer diameters of the Sunnyside ore bodies, which is about N 70° W or within 10° of the strike of the Nickel Plate ore body. It is not to be expected, however, that all the ore bodies that may later be found in other portions will conform to this strike, but it is to be expected that the Sunnyside and Nickel Plate ore bodies, the most distant of which are separated by not more than 2,000 feet, and have similar geological environment. should have some uniformity to trend. While this direction does not coincide exactly with the strike of the major fault planes of the district, it is parallel with certain fracture zones of lesser magnitude, but perhaps of earlier origin.

Boundarias.—As \efore indicated, the boundaries of all these ore bodies are, in general, determined by commercial factors, that is to say, the gold content dies out from a good workable quality into ore which is of too low a grade to give profitable returns. This is the case, as a rule, on both the upper and the lateral boundaries: on the lower or foot-wall side, there is often a sharp and well-detined boundary. In the ease of the Nickel Plate and Sunnyside No. 3 ore bodies, this foot-wall is the gabbro intrusion, which was the cause

of the contact metamorphism and of the primary mineralization.

Through secondary enrichment. the igneous foot-wall may in favour-

able localities contain workable ore, but as a rule the values in it are low, and the boundary of the ore body is the plane of contact

1 Geol. and ore deposits of Cripple creek, Prof. Paper 54, p. 206,

156 Geological Survey, Canada

Letween the igneous and sedimentary rocks. here are other cases (for example in Sunnyside No. 2) where the ore body is not in direct contact with the igneous intrusive, a stratum of the sedimentary rocks acting as the foot-wall. This stratum undoubtedly proved impervious to ore bearing solutions, which followed more easily altered and porous beds.

There are other instances in which certain ore bodies have been proved to have well-defined and clear cut walls, where there has been secondary enrichment by downward movement along the foot-wall to a point where this is intersected by a cross-cutting dike. This is illustrated in the case of the Nickel Plate ore body, when a lamprophyre dike and a porphyry dike, both eross-cutting tha igneous foot-wall, have formed a trough with impervious walls, through which descending waters could not percolate. The same conditions are found in other portions of the district, and seem to indicate that after the formation of the primary ore deposits concentration took place, so that what may have been originally lean ore has been so enriched as to become of commercial value. While the presence of a later dike as the boundary of an ore body is not absolutely essential to a good commercial deposit, the influence of such, in the surface zone at least, should not be overlooked or underestimated, in determining the location of workable ore in a locality which otherwise ight only have contained lean primary ore of low grade. At the same time, it must also be remembered that such conditions are only likely to be a factor in the early stages of mining in the region, and it should not be expected that enriched ore bodies, retained by impervious cross-cutting dikes, will recur at unlimited depth, or even Lelow the influence of surface waters. There we should expect to find the cre bodies in their primary state—true contact metamorphic deposits formed by the effect of igaeous intrusion, and with vague undefined boundaries.

Persistence——In a district as little developed as this, and containing a type of ore bodies which in other parts of the world has the reputation of having been notoriously erratic and uncertain, a diseussion of the persistence of the ore bodies cannot escape a vagueness inherent to the subject. So far as development and experience show, deposits of this general type occurring on actual contacts are very bunchy, and cease in depth. There ure exceptions, however, and where the ore is uniformly distributed through the contact zone

NEDLEY MINING DISTRICT! ORE DEPOSITS ies fi

—as at Cananea, Mexico, and Phenix, B.C.—there is uo theor tical reason why the primary ores should not persist down to the igneous source, and if the theory of genesis is true, there is no reason why they should become lower in grade. In the case then, of the Hedley deposits, their persistence in depth depends entirely on the correctness of the view with regard to the origin of the igneous rocks with which they are connected. It is believed that the gabbro dikes and sheets which either form the foot-wall of the ore bodies on the Sunnyside and Nickel Plate mines, or are closely associated with them, are merely apophyses from a larger stock-like body of gabbro lying on the western slope of the hill. If these then are followed down to their souree they will be found to pass into the stock at a depth dependent on the dip of the dike or sheet: and at this point the ore bodies must cease vertically.

Apophyses of diorite have in several instances been traced to their source in the parent stock, and while actual surface exposures of gabbro apophyses have not likewise been so traced, the geological relations of each of these rocks to the sediments are identical, while the texture of the larger gabbro apophyses can hardly be distinguished from that of the stock. The mineralogical composition too, of stock and apophysis, is the same, so that it is almost certain that the one has its source in the other. Evidence will be produced in a later section to prove that the origin of the deposits is bound up with that of the igneous rocks, so that ore bodies connected with one of the apophyses will persist only as long as they persist, an' will cease when they pass into the main stock. Taking dip and strike, therefore, of any particular ore body, its maximum possible length can on this theory be calculated. Whether it will persist through the whole of this length cannot be predicted, but its maximum length is limited. It is quite true that up to the present time no individual ore body has been mined out on its downward extension, but it is also true that, as depth is attained, the treatment of the ores becomes more difficult, showing that the relation of the gold

to the sulphides is much more intimate. It eannot definitely be stated whether, as depth increases, difficulty of treatment will be

accompanied by a lowering of the grade, because mining has not vet gone deep enough; but once through the zone which is influenced by surface waters, there is no theoretical reason why the values should not remain constant down to the igneous contact.

158 Geological Survey, Canada

The question again arises, with regard to the values in the ore bedy, whether in the primary ores—that is, those which have not heen enriched by descending surface water but are simply the result of contact metamorphism—the values will be high enough to repay the cost of extraction. Any statement on this point would merely be an opinion, and might not be correct. Mining operations have not yet gone deep enough, so that it could be said for certain that the zone of influence of surface waters had been passed through; and further operations only ean settle the question.

Relation to Bedding.—It cannot be laid down as an_ in- Hexible rule that the tavnlar masses of ore of this district lie Parallel to the bedding planes of the enclosing limestones, but it is true that of the known ore bodies the proportions that are in parallel alignment with the bedding planes are in excess of those which are not. In formulating a general rule in this connexion, it would be safer to say that the dip and strike of the ore bodies are controlled by the dip and strike of the igneous intrusives, and these are parallel to each other.

In spite of the extensive alteration undergone by the limestones in the vicinity of the igneous intrusives, traces of the original bedding planes can generally be identified without difficulty. Where the alteration has been extreme, as in the case of the Nickel Plate mine, the actual lines of division between the different strata have been obliterated, and unless examined in detail, the whole ore body appears massive. It appears, however, on closer examination that traces of the original bedding planes are still preserved in the banding, resulting from an alternation of garnet and epidote bands. The garnet bands, in particular, follow welldefined lines in the mass of green epidote or diopside, and these bands coincide with the original planes of stratification. The general uniformity of dip throughout the greater part of the district

is also a great aid in identifying the original stratification planes in restricted localities. On the Nickel Plate mountain, the dips of the sedimentary beds vary from about 10° to 30° W, and the dip of the ore bodies is also all within the limit of those figures. Sunnyside No. 2 ore body exactly coincides with the bedding planes of the limestone. These dip at an angle of 10° to the west, and the ore body follows one of the limestone strata, while its foot-wall is a stratum of white crystalline limestone. It is noticeable, also, that in

Hedley Mining District! Ore Deposits 139

this ore body, sphalerite, which is here very abundant, forms a distinct band a few inches in thickness, which is parallel to the bedding planes of the limest ne.

In the Nickel Plate mine the ore body does not follow continuously the same stratum of mineralized limestone, but cuts across the beds at a sharp angle, and passes from oue bed to another, as it goes downward. This is due to the fact that the intrusive gabbro, which is the foot-wall of the ore body, has not been injected exactly along one of the bedding planes of the limestone beds, but euts across thein at a sharp angle. The dip of the gabbro is from 25° to 30°, while that of the sedime ntary rocks is from 16° to 20°. The ore body follows the igneous rock, so that in the mining of it the operations will follow along one bed for some distance, until the ore becomes low grade, then a jog will be made to a lower bed, and that followed until it also passes into low grade rock. The result is that the hanging wall, if it could all be seen, would appear as a series of inverted steps, with wide flat spaces, and short jogs at right angles to the plane of these.

The principal reason why the ore bodies of the region generally conform to the stratification of the sedimentary rocks is found in the fact that most of the apophyses from the gabbro stock have been injected into the sedimentary rock along the division planes of these rocks. This was the natural and easiest path for these intrusives to -ollow, and especially on the eastern slope of the mountain, where all the strata dip toward the gabbro stock. For this reason tlie same stratum generally overlies the intrusive rock throughout its length, and if this particular stratum held an ore body in one part there is no reason why this ore body should not continue in that stratum.

If, however, the gabbro intrusives cut across the dip of the sedimentary strata, we should rather expect the ore body to lie close to the gabbro, only so long as the composition and texture of the sedi-

mentary strata through which they cut remained constant, in a vertical direction. But if there were variations in the composition

sy

and texture of the strata through which the gabbro intrusive then it would be reasonable to expect interruptions in the cont!

of the ore body. In other words, ore might be confined to a cei: 4 bed for some distance, and then die out, while the succeeding bed on the contact would be barren throughout. In such a ease, an alterna-

160 Geological Survey, Canada

tion of beds might mean an alternation of rieh and barren bands,

and a lack of persistence of the ore in any one of these bands.

Relation to Fissur: -Large fissures as passages for primary ore bearing solutions in the Hedley district are not of great importance. Considerable fracturing and fissuring accompanying orogenic movements have taken place at different periods in the cologie history of the district, but these events were later than the intrusion of the gabbro, and consequently later than the formation of the primary ores. From the great lack of any mineralized fissures connected with the gabbro intrusion it would appear as if the sedimentary rocks of the district were almost undisturbed, and had suffered little deformation before the intrusion cf the gabbro. Naturally, .'uring the intrusion of the diorite and gabbro, some fissuring must have taken place, but this appears to have been on a minute scale, and not sufficient to form large and important trunk channels for the ore bearing solutions, Following these intrusions, orogenie movement opened some fairly large fissures and developed some fault planes, hut it was so long after, that the intrusive rocks were quite eold, and deposition of ore had entirely ceased.

The fissures that were available as channels for ore bearing solutions were, with a few exceptions, very minute indeed, so that we only find some of the primary sulphides filling short, narrow, and irregular cracks in the contact metamorphic zone. There are numbers of these small narrow cracks in soine, but not all of the oze bodies, and these are often found to be filled with secondary quartz. The period when some quartz was introduced into these cracks was the same as when some of the primary sulphides were introduced, or not very long after the intrusion of the gabbro. Other quartz, which fills small fissures, is of much later origin. The contemporaneity of the quartz with chalcopyrite, blende, and pyrrhotite, is shown in the polished surfaces of some of the ores, where these minerals are ali intergrown with each other, and they either fill interstices between arsenopyrite erystals, or small fissures in the ore. It has Leen found :possible to account for the ore bodies being restricted to certain portions of the contact metamorphie zone, and the localization of the values in these bodies. It may be, however, that previous to the intrusion of the gall.ro, there was Widespread fissuring on a minute

seale in a zone where the ore bodies are now located, but that mueh

Hedley Mining Dinerict 3

GORE DEPOSI) Ss

of this tissuring was obliterated by the recryYstallization

Ol thy tact metamorphic minerals, following the intrusion of the gabbry Since the formation of the primary ore bodies there has be il

extensive fracturing und lissuring, accompanied in places by fornuition of large faults. These phenomena have already de discussed in a previous chapter. These faults and fissures

any one portion of the district, but are dis lot it, though uppare

ure noe contined to

tributed over ntly most abundant on the Nieke! Plat

@ lhoui strike in various directions,

tain, They but with a tendeney ty

bes

Most strongly aud abundantly developed in certain directions, The

most important of these directions is N 30° fk. and along this line Inany of the topographie features of the sures with this bearing are abund well marked in the Nickel Plate minc, Less important direetions are N45 W, N 70 W, and N 60 Ie, and ale

many small fissures, and some

district are aligned. Pisant in Sunnyside No. 2, und are

me each of these lines are arge faults.

It is obvious that the determination fissuring, relative to the formation of the ore bodies, is of great cconumie importance, tor if the tissures the ore deposition, then they would be

with ore to a depth as great as their

of the date of this major

were formed previous to expected to be associated

own; while if they are later than the ore deposition, then their influence

euly be confined to the surface zone, or

circulating, resulting merely in

on the ore bodies would where surface waters were the re-arrangement of the ore minerals. In the latter case, the economic importanee of the fissures would not be as great, and would cease when the surface zone was passed through.

From a study of the contents of these maj

or fissures, it is clear that they must be referred to a date

ater than the formation of the primary ores. Even when they cut the e

contain in themselves no ore minera introduced at the time

xisting ore bodies, thev ls which can be said to nave been € Pha Pawaa tthe osietaa" ons. badics

the formation of the origina ore bodies.

Generally, they are merely filled with barr n calcite or¢ ey mutter,

and the small gold value they contain can be readily -ounted for

by the action of surface waters passing through the ore bodies.

These fissures, however, become important factors where they

cut pre-existing ore bodies in the zone of surface waters. Ifere they

have been useful by allowine a free and easy circulation of surface water in transporting and re-arrangine

1e gold values, so as to eon-

162 GhOLOGICAL SURVEY, CANADA

centrate them in certain localities. By the help of these, it is con ceivable that primary low grade ores would become so enriched as to bring them up to a grade that could be protitably mined. And it is a tact that where these fissures are strong and abundant in the surface zone, there the ues are raised to a degree above the average grade of the ore body, where there are few or no fissures.

As in the ease of the larger tissures and fractures, all the faults that have been studied are of more recent date than the formation of the ore bodies. While none of the ore bodies now being worked are known to be faulted in any degree, the above conelusion was arrived at by observation of the relation of the faults to certain planes of fracturing which cut the ore bodies, and are later than them. Therefore it is to be expected that though no instance is yet known of a faulted ore body, there is every possibility of such being discovered in the future.

In conclusion, it may be said in regard to fissures, that because the majoritv—and those the major ones—are later in date than the formation of the ore bodies, they are relatively unimportant economically in the deeper zone, but that in the surface zone they have become useful as channels for circulating waters to concentrate the values in certain localities, thereby raising the grade of the ore. The faults, also, are of later age than primary ore deposition.

The very common occurrence in regions of convact metamorphic deposits, of a swarm of quartz veins in association with the igneous intrusions, does not ho! in the Hedley district. There are ne quartz veins inside the district, other than some small irregular stringers which are connected with the intrusion of the granodiorite, and hardly any are known within a radius of & or 10 miles of here. Certainly none occur within the sphere of influence of the dioritegabbro rocks, a circumstance which is probably accounted for by the low silica content of these rocks. That there was a transfer of some silica from these rocks to form the contact minerals is very probable, but it is also believed that much of the silica present in the lime silicate was native to the intruded rocks.

Distribution of Values.—The distribution of the gold values throughout the contact zone is general, and in the ore bodies themselves, erratic. Proof of each of these statements is obtained from the records of very extensive diamond drilling. performed by the Yale Mining Company on their various claims. Through the cour-

Hedley Mining District: Ore Deposits 163

tesy of the manager of the company, Mr. F. A. Ross, access was cbtained to some of these records, and much instructive information

obtained thereby. Three of these records are here reproduced, In every case the drill core was carefully drawn up and boxed, and

SECTIONS ON ee a S OIAMOND DRILL HOLES

Sena i on and adjacent to AS ij SUNNYSIDE No3 ORE BODY Shewing Veluce Seats

To accompany Reports Nos 1093 cand 1094 Hedley

assays were made at every 5 feet of a portion of the core. No. 66 is part of the record of a drill hole put down at an angle of 25° to the east and directly across the dip of the sedimentary rocks,

164 Geological Survey, Canada

No, 67 is another record of a verticn! drill hole put down in edimentary rocks whieh dip at an anule of about 25? to the west. No, 64 is the record of a drill put down through the Sunnyside No. 3 ore body, at an angle of (4°, almost parallel to its piteh, and about 15 feet above the gabbro foot-wall, ALL of these are ou the same claim, No. 66 being about 120 feet north ot No. 67, and running ut the bottom into the Sunnyside No, 3 ore body, The figures indi

vate the values in dollars per ton of the portions of core assayed.

Numbers G6 and 67 pass from one end to the other, through edimentary rocks that have been completely metamorphosed by intrusions of gabbro apophyses, and some of these apophyses appear in the section. 'The records show the wide distribution whieh the gold has throughout the contact zone, even though th. value rarely exeeceds SO cents to the ton. It is notivoable that wherever the gold values exceed chat tigure there is a sheet of gabbro underneath, Both No, 64, and the lower part of No. 66, traverse the ore body, and the values show the great variation in gold content in very short distances. In these drill holes it is impossible to account for the great localization of values in certain places. No. 64 starts in low grade rock which overlies the ore body, and at the lower end it

passes out again into low grade rock on the opposite side.

Relation to igneous Roeks.—Little importance ean be attached fo the many small dikes of lamprophyre, andesite, rhyolite, and quartz porphyry, as far as contact metamorphism and mineralization are concerned, Their size is generally much too small, and in the majority of cases the sedimentary rocks which they cut had previously been metamorphosed to svech an extent that any additional metamorphisen these dikes might have induced could only have been slight, and is not now noticeable. As previously indicated, however, these smaller dikes are important in the surface zone, not from their composition or power of alteration, but from the fact that in certain instances they have acted as dams to form basins in whch enrichment of the ere bodies has taken place. In such capacity, therefore, the texture only of the dike would be important, and those with fine grain and close compact texture would be more effective than those which are loose and less impervious. The soft greenish andesite dikes are too

porous to form an effective barrier for etrenlating solutions, but

IL DLEY MINING DISTRICT! ORF tt boosts

certain dense black laniprophyres, and the so-called quartz

fre impervious enough for this purpose

Granodiorite lying in the bettors of the Similkameen. s the last in age of the great igneous intrusions of the district jig been erupted after the sedimentary rocks had been intruded and metamorphosed by the different stocks and of the diorite-gabbro complex, it is difficult to estimate the ef alteration that should be attributed to the granodiorit: Kiem a study of its 'tacts, however, which are always well exposed, evidence has been obtained to show that, in proportion to its size, the granodiorite has effected much Jess contact metamorphism than the diorite or the gabbro. Like the other igneous intrusions, on the other hand, the contact metamorphism it has efectol has been apparently greater in the impure siliceous limestones, or the inter handed quartzites and limestones, than in the massive limestones of the Nickel Plate and Redtop formations. Into the latter there b+ been little transfer of material from the igneous to the sedimentar, rocks, but the limestones merely become crystalline, or change to coarse marbles of crumbling granular texture. Where the limestones were thin bedded and impure, and interstratified with quartzites ind argillites, contact metamorphism has been more marked, and the resulting rocks are dense and flinty, and of white, red, or dark ereen colour, These are seen under the microscope tu contain much

epidote, some garnet and chaleedonie silica,and small erystals of

pyrite are scattered through them. The most important addition to the

sedimentary rocks has been silica, The other elements whieh go to make up the contact metamorphic minerals could readily have been native to the intruded rocks, and the heat of the igneous intrusion merely served to rearrange them in different combinations. The mineralizing action of the granodiorite has not been of great importance in the formation of ore bodies. Though some yalues in gold are obtained in certain parts of the granodiorite contact, no notable mineralization hu: taken place that could be attributed entirely to granodiorite, and not to dicrite or gabbro intrusives, which are found in the immediate vicinity. In general, it may be said that apart from silica there has been little transfer of material from the granodiorite, and, exeept perhaps in isolated localities,

none whatever of the metals.

168 Grological Survey, Canady

To the rocks of the diorite gubbro formation must be conceded the most important position, as far as influencing mineralization and the formation of ore bodies is concerned, No contact of these rocka with the sediments ean be examined without showing eon Vineing proof of this, and there can be no doubt that the formation of all the known ore bodies of the district is intimately associated with the intrusions of these rocks. These rocks are the oldest eruptive rocks in the district, and they occur principally in the northern halt, in distinet stock-like bodies, and in a great many upophyses from these bodies. In this portion of the district lie all the known ore bodies, and those prospects whieh show the most promising indications of Geveloping ore bodies,

The diorite-gabbro formation contains two distinct types of rocks which are closely related to each other in origin, and are also connected by transitional types. For the present purpose the transitional types may be excluded as being of very limited distribution, and only the two main types will be considered, namely, diorite and gubbro. The former is a dark rock compound essentially of plagio clase and hornblende, with lesser amounts of quartz; while the letter is a white rock, consisting of plagioclase and pale green pyroxene,

These rocks are intrusive into the Nickel Plate, Red Mountain, and Aberdeen formations in great quantities, but in th Redtop formation there are only small dikes of porphyritic diorite and apophyses from the diorite stocks, The contact metamorphism has everywhere been very marked, but as in the case of the granodiorite, certain kinds of sedimentary rocks have suffered more than others. The massive Sunnyside limestone has been comparatively little affected, while the overlying siliceous limestones and interbanded limestones and quartzites have been thoroughly altered to a mass of epidote, garnet, and pyroxene. Only where the massive limestone comes in direct contact with the stocks, as it does on the eastern slope of Twentymile valley, has there been much contact metamorphism. Here the lime silicate minerals have been developed on the immediate contact, and a short distance from it; and at the same time irregular masses of the limestone have been completely replaced by silica, resulting in the formation of a dense grey rock

flinty nature, which is speckled with small crystals of arsenopyrite.

HERDED vi Ne DPE ERE ES Chie feb ites

In the siliceous fimeston id the . terbunded quartait limestones, particularly in the middle portion of the Nickel P formation, the actions of both the diorite and the gabbre to some extent idencieal Near the larger igneous bodi: alteration has been great. South of Climex bluff, a metam area shows very large crystals of quartz, garnet, caleite, and epid developed close to the gabbro. The quartz forms erystals up to thr quarters of an inch in diameter, Dodecahedra of garnet exhil faces of an inch in diameter. Epidote oceurs in radiating gre erystals, All these are embedded iv crystalline ealeite. On weathering, the calcite disappears, the garnet and epidote fal cut, and the quartz remains, forming a net-work of interlacing prisms, In the same beds, on the eastern slope of Niekel Plat mountain, quartz is not so abundantly developed, but the meca morphic rock is a dense mass of epidote and garnet. These form well-defined bands, which coincide with the original bedding planes of the rock, and these bedding planes have been more or less obilit ated,

In the Aberdeen formation, which consists largely and quartzites, with fewer limestone beds, the metamorphisin is less intense, though here also, a wide zone of contact metamorphism with less mineralization is appa ent on the contacts.

Comparing the effect of the diorite and the gabbro on the sedi mentary rocks, the mai: points of similarity ace quite evident These consist in the powerful influence which each of these ro k- has had on the sedimentary rocks, and in the alteration taking the form of the formation of epidote, garnet, pyroxene, amphibole. and ~ome of the sulphides. Though each of them is known ty ha: arsenopyriie, pyrrhotite, chaleopyrite, . d blende in the contact metamorphie zone, there appears to be relatively more pyrrhotit und chalcopyrite found on the diorite contact than on the eabbro. while blende appears to favour the gabbro rather than the diorite. Arsenopyrite is common to both, and cannot be said to favour one contact more than the other.

It has been shown that on the granodiorite contact there habeen a transfer of silica into the sedimentary, without much aceon panying migration of the sulphide-forming metals. On the other

hand, the contact metamorphism aeceompanying the rocks of the

diorite-gabbro formation has heen more marked, probably because

168 Geologiual Survey, Canada

there has been a inuch greater transfer of raaterial. The amount of silica transferred by the @ orite-gabbro appears to be about equal to that transferred by the grano liorite, but on every one of the diorite-gabbro Contacts, arsenopyrite, pyrrhotite, and chaleopyrite have been formed in quantity, and these evuld only have come from the igneous rock. These minerals do net form in such quantity on the granodiorite contact.

The difference in the effect: produced on the sedimentary rocks hLetween the granodiorite and the diorite-gay>oro may b2 due to physical rather than chemical factors jin the igneous rocks—that is to say. to the heat evolved by each of them, and to containe] mineralizers. In the case of the granodiorite, we have now exposed in this distriet the actual roof of the batholith, which here never reached the surface, though it may have been near it. By the time it reached its present position it was slowly freezing and losing the power to metainorphose the overlying rocks, and was becoming too viscous to send off many apophyses. The diorite-gabbro magma, on the other hand. must have n much hotter and more fluid. The contacts which we now see were not the roof contacts, but the lateral contacts, which must have heen subjected to the heat of the magma for much longer periods. 'That the diorite-gabbro magma also was not viscous, but extremely fluid, is proved by the apparent ease with which it penctrates the sediments, the distances which the apophyses can be traced, and the great number of these, which many times exceed those of the granodiorite. Considering chemical composition of the magma alone, we should expect the granodiorite from its greater acidity to have much greater power to metamorphose than the diorite-gabbro rocks, but in spite of this, the severse is true,

An interesting and important point, which also has an economic bearing, is the fact that all the ore bodies that have up to date been worked, lie on or near the contact of gabbro intrusives. The Nickel Plate and Sunnyside ore bodies lje in a portion of the district where the gabbro intrusives are more abundant than anywhere else, and these are the most important ore bodies, and have. to date, been the most productive. The geological map of this part does not show all the gabbro intrusives that are known to occur: but besides those which are mapped, there are many which are too small to appear cn the map. The accompanying Fienre 5 jc 2 section in detail

across the mountain at right aneles t. the strike of the rocks, and

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PRD) CY MINING DISTRICT: ORE DEPOSI] Joie

shows the relation of the gabbro intrusives to the sediment= which they cut. In the case of the Nickel Plate ore body, and Sunzvsrede

No. 3, a gabbro intrusive forms the fuot-wall, and the ore bodics rest

directly on it. Sunuyside No. 4 has not been sutticientls developed

to show the relationship, but in Sunnyside No. 2, the ore body hes between two sheets of gabbro, not directly on the lower one. but enly a few feet above it, on a stratum of white crystalline limes stone. A low grade ore body in the Niekel Plate mine, whieh is vot at present being worked, lies below the ore body which is new being mined, but on top of a large sheet of gabbro, and below the one which forms the foot-wall of the upper ore body. In other eases, cn undeveloped elaims where higher values than usual in gold have been obtained, a short examination of the neighbouring rocks showed the presence of a gabbro intrusive cutting the scdimentry rocks in which these values were Sound.

The size of the gabbio body appears to have no relation whatever to the richness of the ore connected with it. The rich Nickel Plate cre body lies directly on a small gabbro intrusive, only about 6 feet in thickness, while below this is a much larger gabbro intrusive, of apparently similar composition, over 100 feet in thickness, which has on its upper side a much lower grade ore body. Several other gabbro intrusives in the immediate neighbourhood, some large and others small, have no ore body at all connected with them, though traces of gold may be obtained.

The above facts are very significant, but before any general rule ean be established with regard to the genetic relationship of ore bodies to gabbro intrusives, much remains to be done in the studs of yet undiscovered ore bodies. Recent developments seem to indicate that the diorite itself may alse 'ave been influential in the formation of ore bodies, but these oceurrenees have not been suli.'- ently developed to base any conclusions on. At present, it is safe to say that the diorite-gabbro formation has been the main facte in ore formation. Of the two main types of reeks whieh make up this formation, the gabbro, as far as present development has gone. seems to have been more potent than the diorite.

Relation to Sedimentary Rocks.—The probiem of determinine the geological formation to which the ore hodies of the district belong is not a verv diffenlt one. even where metamorphism has

altered the original texture and composition, and obseured much

170 Glological Survey, Canada

of the structure. The sedimentary rocks have not suffered much deformation from orogenic disturbances, and over the greater purt of the district they preserve a striking uniformity of dip and strike, consequently it is uot dithcult—if certain strata are too much metamorphosed to be easily reeognized—to follow out these strata to a point where their original characters are not obscured and they ean be identified.

At the present time, the Nickel Plate formation contains all the known ore bodies, as well as those prospects which are being most actively developed, on account of their promising character. This formation, as previously described, has a thickness of about 400 feet. It consists, at the base, of the Sunnyside limestone member, 300 feet in thickness. At the top is another massive limestone hed called the Kingston limestone. Between the two beds fie. a series of impre limestones and quartzites, which are often inter stratified with each other in narrow bands. Neither the Sunnyside limestone member, nor the Kingston limestone, have yet been proved to contain gold ores in paying quantities, but the latt.- aolds some promising copper ores on the Warhorse mineral claim, on the eastern slope of Twentymile creek. The central division of the Nickel Plate formation holds the Nickel Plate ore body and the three ore hodies on the Sunnyside claim, and most of the promising prospects of the distr. -t are also found in this horizon.

What determined the location of the ore bodies in this part of the Nickel Plate formation is not immediately apparent. Certainly, one should expect both from its character and location that the Sunnyside limestone would be as favourable for the formation of ore bodies, if not more so, than the impure limestones above it, but no ore bodies are yet known in it. It is evident that the Sunnyside limestone is more resistant to alteration by contact metamorphism than the impure and banded limestones, and this may be due to the fact that the banded limestones offer more and better channels along the bedding planes for emanations from the intrusive rock. For the same reason, these impure banded limestones were more easily end thoroughly mineralized than the more massive compact Sunnyside limestone.

Passing upward in the middle division of the Nickel Plate formation, quartzite bands heeome more abundant in proportion to

limestone, and at the same time inerease in thiekness. When we

HEDLEY MINING DISTRICT: ORE DEPOSITS rg

pass into these quartzites we at the same time pass out of the pro ductive portion of the formation, for quartzites are very resistant to contact metamorphism, and are consequently sparingly minera!- ized,

As in the case of the relation of ore deposits to the agnes 1 rocks, it would be unsafe to generalize, from the information have, on the relationship to the sedimentary rocks. AIL we ean

13 that the central division of the Nickel Plate formation has proved the most productive up to date, and other ore bodies should he found in it; at the same time it cannot be denied that there is a stzone pessibility of finding ore bodies in other formations where we kno

that the same conditions ean be duplicated.

Genesis.

Evidence.—Much of the evidence in regard to the origin of the cre deposits of this region has been alrauly given in pressling sections, but it will be as well to re-state it here, and bring it inte more compact form, before giving the conclusions derived from it.

It has been shown that after the deposition of the Cache Creela sediments, these were uplifted and intruded by the rocks of the 'orite-gabbro formation. These igneous rocks were intruded is. the form of stocks and dikes, and everywhere penetrated the over- Iving sedimentary roeks, producing important contact metamorphism. This intrusion took place in early Mesozoie times, and though it ineludes rocks of two different kinds—namely a diorite and a gabbro—they were erupted at such closely consecutive periods that they may be considered as making one intrusion.

The result of this intrusion was the metasonatie development in the intruded rocks of quartz, garnet, epidote, diopside, tremolite, and other lime silicates. accompanied by much arsenopyrite. pyrrhotite, chaleopyrite, and sphalerite. The effeet on beds of different composition was various. In quartzites and argillites, the metamorphism was comparatively slight, on massive lime-tone it was more effective; but on thin bedded impure limestone. or interbedded limestones and quartzite, the offset was most pronounced, resulting in the complete elimination of the calcite and development of the lime silicates.

During this intrusion, also. there was considerable addition of

material to the contact zone from the igneous roeks. Undoubtedly

ba 'EOLOGICAL SURVEY, CANADA

-ome silica was introduced, and at the sau time, oxide of iron, copper, zine, sulphur, and arsenic in sutiicient quantity to form here and there notable deposits of arsenopyrite, blende, chaleopy rite, and pyrrhotite. All of these sulphides are uaknown in the sedimentary rocks at a Gistanee from the igneous intrusives. Other additions received by the contaet zone were small quantities of boron, which went to form axinite, and it is beliesed that the gold was also introduced at this time. Assays made of the intrusive gabbro, associated with the ore bodies of the Niekel Plate and Sunnyside mines, indicate the presence of gold in varying amounts. As a rule, these are merely traces, but oceasionally a sutticient amcunt is present to form ore. In the latter case it is certain that the presence of the gold is due to enrichment from the overlying sedimentary rock, and one ean never be absclutely certain that all ef the gold could not be referred to the same souree. This argument, therefore, must be used with some care.

The intimate intergrowth of all the sulphides mentioned above, with the gangue minerals, proves that, except to a very limited extent, they are not later introductions, but that they are all contemporaneous in origin. and due to the same cause. No important additions of material from a deep-seated source were received after the completion of the eontact metamorphism due to the igneous intrusions, for the later fractures and fissures are not mineralized, and contain only barren ealeite and quartz. Yet these later fractures and fissures were important in the surface zone, in allowing a free circulation of atmospheric waters, which tended to concentrate the gold values in favourable localities. That this later arrangement of the values was due to surface waters moving downward is proved by the localization of the highest values on the igneous foot-wall. and the concentration of these values on the upper side of impervious dikes of later age whieh fornel troazhs or

basins. (See Figure 3).

All of the known ove bodies are not widely separated from each other, but are segregated in the north central portion of the district, around the stecks and dikes of the diorite-gabLro complex. It has been shown that all these ore bodies are found on the contacts of the rocks of this complex with the sedimentary rocks. To restrict tne occurrence further, it was stated that the best and most pro-

ductive ore bodies occur on the gabbro contact, rather than on the

HEDLEY LiN G DISTRICTS Of}

diorite. To make further restrictions, it was seen that while mass limestones were readily altered by igneous iutrusivas, thes were more favourable for the formation of copper deposits than of wold: the wold deposits, on the other hand, favoured the impure or thiuinhedded Hmestones which were most causily altered by the intrusi rocks,

The primary ores o! the district have no evident connexion prominent fissures. he fissures that exist in the ure bodies are of later formation, and contain little else than barren caleite quartz. If fractures or fissures existed before the inteusion of the igneous rocks and the formation of the ore bodies—and it is vers probable that they did—they have been completely obliterated by the reerystallization whieh took place in the contact zone at und immediately following tle intrusion, The enriched ores, on the other hand, of the surface zone, have a direct connexion with fissures, and by affording channels of easy circulation to the surface waters, considerable enrichment has taken place in pockets or troughs, having more or less impervious boundaries. 'The depth to which this factor might be important has not yet been ascertained.

The ore bodies are generally tabular in shape, and dip at comparatively low engles. Although controlled to a considerable extent by the bedding of the sedimentary roeks, they are more certainhs dependent on the dip and strike of the intrusive rocks with whieh they are associated. If the dip of the intrusive rock coincides with that of the sedimentary, then the ore body lies in the same stratum throughout. If, on the other hand, the dips of these two rocks do not coincide, then the dip of the ore body follows that of the intrusive rock.

Tt has been shown, also, that the boundaries of the ore bodies are not clean cut, but that the gold values gradually fade out into low grade rock. Neither are these values evenly distributed throughout the whole ore body, but the ore is rich in spots and Jean in others. At the same time, gold is widely distributed throughout the contact zone formed by the gabbro intrusive, but it increases

u great many cases as the contact is reached. In most eases of

the known ore bodies, the highest values are obtained direetly o:

the gabbro contact, and on the upper side of the gabbro. Niekel Plate and Sunnyside No. 3 ore bolies a gabbeo intraisive

nets us the feot-wall, In these 3, also, part of the gabbhro is

174 Geological Survey, Canada

mined as ore. A small assay value in gold can generally be obtained from the gabbro intrusives that are connected with the Nickel Plate and Sunnyside ore bodies.

From analysis of the different sulphides oceurring in the ore bodies, it was found that while all have some gold, as well as silver, the highest values lie in the arsenopyrite. Analysis of pure arseno pyrite taken from the ore body gives a gold content varying from ©.20 of an ounce in gold up to 12-88 ounces per ton, In this, ne volt whatever was visible under the microscope, and it was concluded that it must be either in a very finely divided state in the cleavage crachs of the arsenopyrite, or it was in actual solid solution in the arsenopyrite. In the former case, possibly, and in the latter case, certainly, its origin must have been contemporaneous with that of the arsenopyrite, and it was introduced at the same time,

While it is a rule that all workable deposits must contain arseno-

pyrite, and that the richest ore bodies contain more arsenopyrite

than the poor, it is also certain that much arsenopyrite occurs throughout the district which will give little or no gold values on assay. Where, however, arsenopyrite occurs in the metamorphosed sedimentary rocks on a gabbro contact, it will always be found to contain some gold.

Finally, the gold values have been later concentrated by downward moving surface waters, not only on the foot-wall side of the ore body, but in impervious troughs that have been formed by the conjunction of a cross-cutting dike with the foot-wall. In certain eases, the highest grade of ore ever mined in the district has been recovered from such a trough, at a distance of 200 feet below the surface.

Theoretical Considerations.—In vieve of the evidence that las been brought forward with regard to the oecurrenee of the ore bodies, it seems clear that there is only one possible theory that will satisfactorily account for their formation. Other — theories have been suggested during the progress of the work, anJl these also will be briefly discussed. Contact metamorphism, during which the primary ores were formed, accompanied by later secondary enrichment by downward moving meteoric waters, will, in' the opinion of the writer, satisfactorily explain every known occurrence

of workable ore hodies in the district.

HELLEY MINING pISTRICT ORE PEPOsiES

bodies with the recks of the diorite-

The association of the ore the gabbro, is a

gubbro formation, and particularly with nd to these intrusiot believed that the ore

provel is it is t ia primarily) believing that contact me vagina that has be

fact, a

due, All geologists agree in tamorphisim due to the heat of the The great majority i very large extent by the ac

iven off by the molten magm4 and trans- e was undoubted!)

molten also believe that this metam-

tion of water and

in rocks is forced into them.

orphism was aided to t

other materials, which were £

d to the intruded rocks. In these cases ther

the contact zone of the which are not native to

in them; and

ferre sedimentary

a transfer otf material into rocks, for we the sedimentary believed that all these subs Among these various Gold, also, is believed tv for assays of the gabbro gabbro carries

that zone not found elsewhere wriginally contained in

find substances in rocks, and are it is tunces were ¢ the igneous magma, substances are iron, sulphur, and silicc

the gabbro magia, gold. In places the but these are always p) £ secondary enric

zine, copper, arsenic, have been present in

ally reveal traces of aces where the

hi

how gener much that it 18 mined as ore,

introduced later, in the process 0

vold has been ment.

This gabbro magma, as very fluid, forced its way upwa As it reached higher levels, ances, including gold, were there to assist in

which, as has been shown, must have been

carrying all the subst rd through the overlying

very hot, and w ances mentioned

above in solution, sedimentary rocks. the pressure gradu-

ally diminished, and the dissolved subst

'nto the adjoining rocks, phism, and to do the mineralizing.

f limestone which are more thinly bedded, and afforded

,dding planes for the emanations,

released and passed off

the work of contact metamor

Those strata © channels by their be

the easiest rphosed, and received the greatest addi-

were the most tion of substance; estones, suffered less.

highly metamo while quartzites, In this way the primary ore deposits were

argillites, and the more compact

lim formed at and near the That the ore deposits

ciated with the dikes an is not peculiar t¢ these

immediate contact of the gabbro-intrusive.

in this district are more than with the main stocks 1

generally asso-

apophyses s a phenomenon which contact metamorphic but is common as well. The rea-

partially explaine 1.

deposits alone, to other districts con has only been Lindgren. in dissussing :

ne copper deposits of Clifton-Morenci, Say*:

the genesis t

. Ne. 43, 1905, yp).

174 GhLULUGICAL SURVEY, CANADA

These contact metamorphic deposits som wer at the mediate contact of the iain porphyry stole aud the limestoae But more commonly they seem to be connected with dikes of the same porphyry, close to the principal mass, these dikes being prob bly more highly charged with magmatic waters." The idea good one, and appears to be borne out in this distriet, foe noticeable that even if economic deposits are mot formed, the mineralization seems to be much more pronounced on the contact of the apophyses, than on the contact of the main stocks.

The cepth at which the ore forming substances were released from the molten magia snust have been considerable, so that the present outcrops were originally deep seated, and have only been exposed by a great deal of erosion. Garnet, epidote, diopside, and tremolite are the typical gangue minerals of these deposits, and in wx recent classification by Lindgren! of minerals formed in ore ck posits under varying conditions of depth, all of these minerals ave classed as typical of the deeper vein zone, and below this. None of them are found in what he called the middle and upper vein zone, or the surface region. Their presence, therefore, in these bodies, shows that they were formed under conditions of considerable pressure, and much below the level of the surface as it then stood.

After the formation of the primary ore bodies by the intrusion of the gabbro, there was little, though some, later enrichment from the same magmatic source, Few fractures or fissures wece former Ls the cooling and contraction of the igneous rock, and of the eontuet zone; but those that did form were useful as channels for the introduction of some of the enriching sulphides. Subsequent to this, ore deposition from the same source was entirely at an end. Later, fractures were formed, but no new additions were rec: ived through them, from a deep-seated source. Not until these ore bodies. through erosion of the surface, came within the zone of influence of surface waters, was any change effected. Then the fissures, previously formed, permitted a free circulation of water, and the gold, leached out from its associated sulphides near the surface, wos Carried downward to enrich the ore body in' favourabl> localities 1 low.

The above, in the opinion of the writer, is the most probabls

theory for the genesis of these ore deposits. Alternative theorjes

Wo fandgren. The relation of Ore-deposition te Phesical Conditions

HEDLEY MINING DISTRICT: OBE DEPOsITs

have been suggested, but none seem to fit the conditions so well us the one outlined above. Tho theory of deposition wholly trou solutions introduced through fissures from below is untenable. It has been shown the: the fissures associated with the ore bodies are of a later period of formation, and if they have been used as channels for ore-bearing solutions ascending from below, some deposition of ore minerals must have taken place on their walls to give evidence of their having passed through them. These fissures are, however, not mineralized with primary sulphides, and contain only barren quartz or calcite, It is certain, however, that these fissures wore useful in the surface zone to concentrate the gold values in low levels.

Another theory supposes the gold to be contemporaneous in origin with the sediments, and to have been deposited at the same time in the sea. In support of this 's brought forward the fact that in certain beds gold values are widely and uniformly distributed through the sedimentary rock. The record of diamond drill holes Nos. 66 and 67 shows this to be true. But these are beds that are well within the sphere of induence of the gabbro intrusive, and it cannot be definitely proved that where these rocks are unaffected by igneous intrusions, the same results would be obtained. Tho fact also remains that no ore bodies have yet been found in unmetamorphosed rocks, nor in rocks that have not been metamorpheced by the rocks of the diorite-gaboro formation.

Conclusions And Classification,

From the arguments presented in the preceding sections of this report, it is concluded that for the primary origin of the ores of the Hedley district, all agencies must be excluded, except those which are connected with the actual intr:sion of molten magma into the sedimentary rocks, and that the ore bodies are of contact metarmorphie origin. Contact metamorphic deposits have come in recent years to take a definite place in all genetic classifications of ore deposits, and the definition of W. Hl. Weed is one which is now generally accepted for deposits of this class. Weed says:' 'Under the title of contac: metamorphic deposits I includa all ore deposits which result from the metamorphic action of intrusive igneous rocks upon the sedimentary rocks which they penetrate. Such de-

posits oceur only in the zones of altered sediments about igneous

Ore Deposits near Igneons Conta ts" Trans. A.T.M.1 102

9185—12

17s GEOLOGICAL SURVEY, CANADA

intrusions; they are genetically connected with such intrusions, nel wre, ther re, fittinelsy designated , ore cleposits of contaet metamorphic origin.'

The conclusion arrived at for tha genesis of the Hedley deposits is one which had previously been accepted by those of the best mining geologists who had the opportunity of studying them, Mr. W. HI. Weed was the first. to make wox published statement with regard to the origin of these deposit In this, he refer these deposits to the contact metamorphic geoup, but limits them to a distinet type which he calls the Similkaueoa typs. This conclusion was arrived at apparently without having seen the deposits, and merely from information obtained from those who had. Sinee then, Mr. Weed has had the opportunity to examine them: and as no published statement has ever been made to contradict. o: modify his former opinicn, it is inferred that he agrees with the original conclusions. Mr, W. Lindgren, whom it was th: author's privilege to have look over a representative ealleetion of the Hedley Ores, concurred in the opinion previously formed that the deposits were of contact metahorphie origin. He, also. in a recent Classification, limits the Hedley deposits to one of four types into whieh he divides the contact metamorphic deposits. This type he calls the arsenopyrite type, because it contains arsenopyrite as the principal ore mineral.

As a type of contact metamorphic deposits. the Hedles deposits are ina class by themselves, as far as North \.ueriean ore deposits are concerned, A search through the literature of North Ameriean ore deposits reveals nothing of an exactly similar character, so that, as far as th. country is concerned, the ¥ are unique, This facet has ef contact metamorphic origin, Ife, also, in a recent: classi cation, of ore deposits, and a separate division has been made to hold them. Ii Germany, however, at Reichenstein? 9 somewhat similar deposit, which contains arsenopyrite as the principal ore mineral, has been mined for a number of years. Here the ore occurs on a contact of serpentine with limestone. The serpentine is supposed to have been originally a feldspar augite rock, which. by its intrusion through the limestone, has effected the usual contact metamorphism with the development of arsenopyrite, as well as other sulphides in the contact

1 Ore Deposits Near Igneous Contacts." Trans, A. I. M. E., 1902, *Stelazner-Bergeat, Die Evrslagerstatten.

PDELEY MINING BISTHIETS ORE PRPOStIE Wey

yone, 'Lhe arectopsyrite, ie at Hhedley, is weld-bearing, ued the tities of Reichenstein, in the year L004, mined 5,526 tona of ore, trou which were extract: by smeiting, some 45 kilograms of wold, The

iiines were worked as long ago as the thirteenth century, and were very a tive during the sixteenth century. For many years, however they remained idle, and operations were only resumed in Ps50, The

Hite of these mines, therefore, has been very long

Ag Of The Ore Deposits

If we accept the theory of genesis propounded in the preceding section for the Hedley ores, we have no difficulty in assigning their formation to at least a relative age in the geological history of the distriet. Accepting their origin' as due to the intrusion of the rocks of the diorite-gabbro formation, then their deposition took place at that time. The date of the intrusion of the diorite-gabbre cannot be definitely fixed, more than to say it is post-Carboniferous in aye, sinee it: is intrusive into Carboniferous sediments. [tis believed that this intrusion took place immediately after the Car boniferous sediments were laid down, or early in Mesozoic times, and may have accompanied the uplift of thes. sediments. The primary ore deposition was effected at that time, and no new material has sinee been added from a deep seated source. Since then, erosion has been going on without interruption, and great thicknesses of the overlying rocks must have been worn away, and probably also mt th of the associated ore-bodies.

As the region has never been submer, 1 beneath the sea sinee the close of the Carboniferous times, and its surface has been continually exposed to the action of atmospheric agencies since then, secondary processes, connected with oxidation and enrichment, must have been in operation for very long periods indeed. I[f the ore bodies ever extended upward in the sedimentary rocks bevond the present outerop. at the beginning of the glacial period, there would have been a conside rable accumulation of gold in the surface zone ct these bodies. The great erosion accompanying the glacial period undoubtedly would carry much of this away. Since then the time elapsed has not heen great, and oxidation has not been able te penetrate more than a few fect. so that the ore bodies are not as rich as they might have been. The present enrich nent, however, might represent some of the pre-glacial enrich vell as all that

ass 12)

Iso GEOLOGICAL SURVEY, CANADA

Which has taken place since that period. The process has, nu doubt.

been a long continued yne, and the intrusioa of certain 3 nall

andesitic dikes, through ove bodies that appear to have been already

enriched, indicates a period of enrichment almost as far

the granodiorite intrusion. &

Mining, Milling, and Metallurgy.

The methods of mining employed in the Hedley district are not essentially different from those employed in other districts on ore bodies of a similar character, but somewhat different from those in use in fissure veins and like deposits. The earliest methods of mining, in nearly every instance, were by means of glory holes, but when these became too large, or so deep as to increase the cost of mining, tunnels or inclined shafts were driven and sunk, and the ore stoped out from either side by the overhand method. Timber is scarcely used at all, except in the tunne! entrances, and in broken or fractured parts of the mine. The rock is so strong that it will generally stand unsupported for a great width and considerable height; but for the safety of the miners, when the chambers become very wide pillars are left for the support of the roof. In the Nickel Plate mine the roof is firm and strong, and no danger is ever experienced from falling blocks. In Sunnyside No, 2. however, where the gangue of the ore is largely calcite, some care has to be exercised, particularly in the spring, when much water is seeping through the walls and roof from the melting snows on the surface. Accidents, however, from falling blocks are rare.

A favourite method of stoping emploved the Nickel Plate mine is to break down a lot of ore, commencing on the foot-wall and working upward, and using the broken down ore as a floor on which the miners work. In this way, a great deal of ore is broken down, and lies in the shoots ready to be drawn off. A quantity of about *00 tons or so is kept on hand.

In the Nickel Plate mine cars driven by electricity. enter the working tunnel, and are loaded directly at the sh ts, or from the face of the drift. Two ton cars are used, and from here a train of ten cars is hauled by an electrie motor to the ore bin at the head of the gravity train. Compressed air is also used at the heads of inclines as an auxiliary power, and this is supplied either from a Steam or water-power compressor. The latter is situated at the

Plate Nin.

Gravity tram line, lower section.

9185 —p. 1S0

HEDLEY MINING DISTRICT: ORE DEPOSITS 1s1

4,000 feet below the tunnel mouth. From the Sunnyside workings, trains of twelve 2 ton cars carry the ore to the bin, where they are dumped mechanically an nvention of Mr. G. P. Jones, superin-

bottom of the Similkamen valley,

ingenious contrivancé, the i tendent of these mines.

All ore mined goes to the except the drift, which is scraped off th by scrapers. No sorting whatever is done e of the different grades of ore, the average and much low grade

mill, and there is virtually no waste, e surface of the ore bodies ither at mine or mill,

but ly a judicious mixing value per ton is kept at a fairly constant figure, ore is mined thereby which would be unprofitable if mined alone.

Exploration in former years has not been kept much in advance of actual mining, and the mines have been leading a hand to mouth existence. Within the last two years, however, there has been a change for the better, and a great deal of exploration has been done, by means of the diamond drill, and by open-cuts.

Accurate data with regard to the cost of mining are not avail-

able. Some of the or2 is so hard that the cost of drilling is not always the same, and frequently runs high. The lack of the necessity for timber in the mines. and the glory hole method, make mining cheaper now than it will be when greater depth is attained. The use of water-power to generate electricity, and to run the air compressor, reduces costs somewhat, and the advantage of using 'vity alone to transport the ore part of the way from mine to also economical. Altogether it is safe to say that mining ransportation will not cost more than $2 per ton, aud $1.75 would probably be nearer the actual figure. Up to the present time, the ores of the district have been subjected to three different methods of reduction, namely, amalgamation, cyanidation, and smelting. The two first named of these operations are carried on in the district by the Daly Reduction Co., while smelting of the concentrates recovered after amalgamation is done

at a smelter at Everett, Washington, U.S.A. This smelter is the

only one in the west which at present will accept arsenical ores.

All the ore extracted from the mines of the district is tre hy the Daly Reduction Co. in a 40 stamp mill and cyanide plant, which is situated at the bottom of the Similkameen valley, 4,000 feet below the mines. Connexion between the mines and mill is cffected partly by means of electric tramway, and partly by gravity

ated

1s? GEOLOGICAL SURVEY, CANADA

tran, The electrie trailing is over one mile in length, wel trains of 10 or 12 two ton vars transfer the ore from the mine to a large bin at the head of the gravity. tram-line. The gravity tram-line is about 10.0005 feet in length? and has to avercone a ditfertnes in elevation of about 3.c00 feet. The grade of this is such that transportation can be effected entirely by gravity, though in the upper half compressed 5' - is used in addition to gravity. The track is three-railed, except at the central passing stations, and is built almost entirely on the ground. It follows the slope of the moun-

tain, so that the grade varies all ¢' way from LO per cent up to

66-8 per cent. The cars are 5 ton skips, attached to a heavy 42

strand wire cable, whieh passes over a head gear at th, top. The loaded car going down pulls the empty car up. The gravity tramline is divided into three sections, on account of slight bends in the line, and it is operated trom end to end by four men. They handle 150 tons of ore in 10 hours, but this amount eould bo largely increased, if necessary,

The stamp mill at the base of the mountain is also built on the slope. so that ore entering the bins at the top of the mill will travel from one stage of treatment to another by gravity alone, The whole plant is very substantially built. its foundations resting on the soll granite, and at the time of its completion, 3 years ago was ¢ uplete and up to date in every respect. From time to time, slight changes have been made to keep up with the more recent advances in mill practice, and to meet the various changes that have taken place in the character of the ore. Power for the different units is supplied by water, which js brought in a 4 ft. x 59tt. fume frem nearly 3 miles up Twentymile creek,

From the gravity tramway the ore is delivered to a bin at the top of the mill. After passing over grizzlies, it goes through two Farrell type jaw erushers of 10 inches x 20 inehes and 6 inches x 20 inches openings respectively. These discharge to a belt conveyer, which distributes the ore along the entire length of a 1,000 ton storage bin, and from this it passes through automatic feeders to the eight batters of five stamps each. The stamps weigh 1,050 pounds each, and they drop about 100 times a minute, into Homestake mortars weighing about 8,000 pounds each, and set in cement on the solid granite. The amalgamating plates under each battery of stamps are

16 feet long and 54 inches wide, arranged in pairs. Only the upper

pgp ape co pune [Loe Lene ass

ogy deronperyp STEEL Ede

"Nn Slvi

HEDLEY MINING DISTRICT: ORE DEPOSITS Is3

mie of each pair is now used, as the character of the ore milled lias rendered the lower plates almost uscless.

On the battery floor, also, there ure three separate water wheels, A 36 inch wheel supplies power for the crusher and belt 'onveyers, a ineh Pelton is connected with the cam-shaft, and a 24 inch wheel drives the vammers on the floor below.

From the amalgamating plates, the pulp is classified and goes to Frue wanners. These are ft in number, 16 boing provided with smooth belts, and receiving the fine product of the elussitiers, and 5 having corrugated belts, which treat the coarse product, "The con contrates recovered from these, which consist very largely of arsenoe pyrite, are sacked and. stored, and later shipped to the smelter at Everett, Washington, GSA.

The tailings from the vanners are again elassitied to sands and slimes, and the whole product. is treated in the various portions of the cyanide plant. This consists of solution, slime, and settling tanks, with strong gold and sump tanks, filled and discharged either by gravity or by centrifugal pumps. The tinal tailings are then sluiced into the creck.

The strong gold solution afterwards passes to the zine boxes, v her: the gold is precipitated from solution. The- precipitate is after: wards treated with sulphurie acid, and then washed and dried, after which the product goes to the furnace and is reduced, and the bullion cast into bars.

Near the stamp mill is also a power plant for generating electricity and compressed air for the mines. It is run by water, a head of 414 feet being obtained from the penstock at the head of the flume, which furnishes a pressure of 190 poun ts to the square inch. A 16 ft. Pelton wheel drives a Rand compound air-compresser. and a smaller 24 inch Cassel wheel, of 100 horse-power, 15 connected to an electric generator. The Rand compressor furnishes compressed air for the hoists and drills at the mines, through a 6 inch pipe line 18,000 feet in length. The pressure delivered at the mines, after an elevation of about 4,000 feet, is about 100 pounds to the square inch, The electric generator furnishes power for the mine tramway, and light for the town and mine buildings. During the winter months, when water is scarce, power is generated by a 140 horse-power Ball

steam engine. whieh also heats the mill.

I1S4 Hlological Survey, Canada

Carpenter, blacksmith, and repair shops are also part of the equipment. A telephone syste.n coaneets all parts of tha mine, tramways, and mill wfth the main office and with each other.

Under the present Inunagement, a number of improvements have been made in the mill practice, The duty of each stamp has oon considerably increased, and is now about 3-35 tons per 24 hours. The quantity milled daily at this rate amounts to about 135 tons, As the ore is an auriferous arsenopyrite, gold is virtually the only product, and an extraction of about 92 per cent of the total value of the ore is made from amalgamation, cyanidation, and smelting, A ~mall percentage of copper, silver, and some platinum is known to occur in the ores, and essays show a variable proportion of cobalt, nickel, lead, and bismuth. The arsenic is a waste product so far as the mines are concerned, and no credit is given for it by the smelter.

Since the inception of the processes of reduction of the ores in the spring of 1904, a total of 153,003 tons have been treated. 'All of this ount has been derived from either the Nickel Plate or Sunnyside mines, and treated by the Daly Reduction Company's plant. Below is a tabulated statement of the number of tons of ore mined and treated annually :—

Nickel Plate. Sunnyside, Total,

Tons, Tons. Tons. BOONE cain 8 story a seen od. oa Pet ace ees Raieyatna's 9,000 So Se nas eck ri 17,437 14,994 32,431 1906, en Geen Pere Wane tes Atle Sr ere 35,000 1907 mae ea P Aor Can eee Sora acouens Eira Ewin Means NO 31,576 : eee ; Paces eH e eNig ea Reel ogee tie 45,006 153,013

General Status and Future Possibilities.

The Hedley district stands at present in the position of a mining camp with a great many undeveloped and even unprospected mineral claims, and only two producing mines. The great majority of these claims are surveyed and Crown granted, so that no annual assessment work is necessary for the owners of these to hold them. The result is that all this ground is tied up, and little is being done to demonstrate to the outside world the potentialities of the district,

HEDLEY MINING DISTRICT? ORF DEPOSITS Iso

new ore bodies be inge discovered. Some,

or even the possibilities of ditheulties and miuains

however, of these owners, in spite of great have preserved their faith in their claims, and

discouragements, above that demanded

continue to do ea h year some work over and

by law, with the result that the value of their claims is enhances and prospective buyers are more easily enabled to form an opinion as to their real worth. In justice to many other owners of claims enid that to a man of limited means the and the uncertainty of knowing where

it is no wonder that

in the district, it must be difficulties to be overcome, to do their prospecting, have been great, and many have become discouraged.

In the early stages of mining in this district, less than ten years looked bright, and much prospecting was carried on

ago, the future As time went on, however, and

in and around the Hedley district.

promises of cheaper transportation by railway connexion with out-

were not realized, the hopes of many fell, their enthus-

side points wether for other places

iasm waned, and some left the district alte where conditions looked to them more favourable. Less and less work was done each year, and when a Crown grant was obtained, it

meant in many cases the cessation of work altogether.

To ade. to the disadvantage under which the district laboured

from lack of transportation, was the difficulty of knowing wher

to look for ore. To the average prospector the occurrence of ore of this type is strange, and even in the ease of a great many mining engineers it takes a thorough study of the geological they ure able to do intelligent prospecting and development were no well-defined leads to follow, and no quartz

conditions

before work. There veins. Free gold was rarely to unlike mineralized country rock, which contained little that For a long time operators in this

1e seen, and good workable ore looked

n was of economic importance. district were working in the dark, and even at the to follow closely what ore they have in sight,

resent time the best they can do is bold enough to run long tunnels, or sink shafts in the idea of striking ore at a certain expected fefore the contact metamorphic origin of 1 the uncertainty and irregularity that ore bodies of that character had only

and none are barren ground, with point. It was some time I the ore was recognized, an are generally connected with te be ascertained by much prospecting in which there was a great

deal of useless work. Again, the ore is of such a character that.

1s6 GEOLOGICAL SURVEY, CANADA

us a rule, one can tell very little about its value from an examination of a sample by the eye alone. Chemical analyses are the only means of acquiring that knowledge, and the expense of continually having assays made soon becomes too greet a burden for the prospector of limited means,

The drawbacks, therefor + to successful prospecting im this district have been exceptionally great; and when it is eoutented that after about ten years of life the district has only produced two working mines, because there are no others to be found, the above disadvantages must be borne in mind. To offset these, and to give some aid to the prospeetor, the work of the Geological Survey was instituted, and already the work has borne fruit. It is hoped 'that further benefit may be derived from the work when the results obtained become more generally known.

At the present time the industrial activity of the district depends almost entirely on the operation of the Nickel Pluie and Sunnyside mines, by the Yale Mining Company, and of the Daly Reduction Company's stamp mill, These two Companies employ altogether ebout 110 men when in full working order. The mines, as well as the mill, are ii operatyon on an average about LO months in the

. and they are only forced to close down durin the remaining iyo months by a lack of water for power for the mill. If the water supply was constant or greater, There is no reason why, with proper conservation and protection of the water they have against frost, the mill could not be kept in operation constantly, and mining be carried on at the same time. The district, however, is a semi-arid one, and the searcity of water at all times of the year is a problem which future operators in the distriet will have to face. On the two mines, active work has been carried on by the Yale Mining Company for the last ten vears, and at the present time their annual output is about 36,000 tons of ore. All of this is treated by the Daly Reduction Company, whose mill has now been working about tive vears,

No other claims in the distriet have so far produced any gold, and few have had much work done on them. The Kingston Mining Company. owning a group of claims on the Twentymile slope of the Nickel Plate mountain, has been the most active, and though working somewhat intermittently for several vears. has' done much to

prove the value of the claims,

Pistia PE Oe DP POstis

Hedley Mining

clitheult im the Hledley district to get aways from

Although it 1

the auction of mineralization, there are to outerops khowi-nutn

nines ~whieh suggest a richie

than those on the two working ores of the Niekel Phato amin

approaching that of the bonanza These ores were net only very f about 200 feet vertically

already worked rich on the surtae but the high values persisted to a depth from the surface, or nearly JOO feet along the piteh, These ores,

which were mixed with a poorer quality of ore to preserve a con

been the mainstay of the district since the period

stant grade, have An unknown quantity of this yet

when extraction of gold began.

remains, but all of the ores must suffer some lessening of grade, a

the upper enriched zone is mined out.

The search for the outerop of an ore body of similar value to the

Nickel Plate ore body has been in progress ever since first discovered, but apart from the ore bodies on the Sunnysile Whether any exist is still the

the camp was

mine, no others have yet been found,

If our theory of the genesis of the ore bodies be true, thes

problem. 1 the most favourable portion of the whole

ore bodies are located it district, for here the necessary geological conditions of igneous inaccompanied by the proper topographic conditions the dip of the sedimentary

trusion are for

the concentration of ores, that is to say, of the gabbro intrusions, bears such a lation and erosion of the sur Where such condi

stra-a, and relation to the

slope of the ground that continued oxi face would always be conducive to enrichment. could be exactly duplicated, there would be a chance As the sedimentary strata of the dist.

for similar

kinds of ore bodies. all 1 the west. eastward facing slopes are more likely

enrichment than those which slope in the

tions

have dips towart to produce strong surface

other direction. Where gabbro intrusives occur under these conbeen found, and should reeur again

ditions, enriched ore bodies have sched ore bodies are likely to occur

On westward fecing slopes, enrit only under peculiar conditions, and the normal unenriched ore would

be more in evidence.

With such surface enrichments, however, the future of the dissatly concerned as it is with those ores below the not been concentrated by surface agencies .¢ must be worked out, and the lower

These must be the ores on

trict is not so gre surface zone, which have Sooner or later, all surface ore crade ores of the deeper zone developed. which the future of the district will depend.

; 33 GiOLUGICAL SURVEY, CANADA

Up to the present, little has been done to demonstrate the extent

or Value of these primary ores, but this has been due largely to the isohition of the district, and the necessity of having fairly high grade or ores of at least #10 to the ton, to repay the cost of mining

treatment

It is ccrtain that much ore of a low grade remains untouched on the Nicke, Plate mine, and is not now mined on account of the high cost of mining and reduction, With improved methods of mining, change of treatment, or cheaper transportation, much of this could be utilized protitably, and undoubtedly will be, at some future date All prospecting in the district, for reasons already given, ia expensive; but a systematic search for ores of a grade about $8 or $0 to the ton, should reveal some ore bodies, especially in the cirele ot which Climax blutf forms the centre, and within a radius of one

mile. No such systematic search has yet been attempted, except in

restricted areas, so that our knowlel: of tae distribution and recurrence of the ores is far from complete, Phe outlining of the Nickel Plate formation, in which the Sunnyside end Nickel Plate ore bodies occur, should aid this search cousilorably, and every

contact of gabbro intrusives with the caleareous members of this formation should be closely studied. When this is done some new ore bodies should be discovered.

Though the chemical characteristics of the Nickel Plate formation are duplicated in portions of two of the other formations of the distriet, the situation of hese formations with relation to the gabbro rocks is not so favourable, and it is probably only this reason that might militate against the formation of ores in them. If well exposed rocks make prospecting easy, then the Hedley district is not difficult, but is well favoured. Diamond drilling could be earried out with good effect in the search for new ore bodies, and in fact has been used very extensively by the Yale Mining Co. Owing to the illdefined nature of the ore bodies, the effectiveness of diamond drilling is not as great as it might te in districts where the leads are better detined and more regular, but this method undoubtedly gives better results for the same outlay than any other kind of prospecting. The idea of driving long tunnels in harren rock, with the hope of striking ore bodies at expected points, or of discovering new ones, has nothing

to recommend it in a district carrying ore hodies of this character.

oh necinbiecsahaiisite sbiils bbamenibbansits ca

srasieresanacbbane sabeee=

tv DISTRICR) ORT pEPOSITS 1S')

here they are known, run

ute nriehed ore', W that other factors, such

Lhe slues an e prese nt actual cos er of rock, ant e of any sue

t of extraction,

mining facilities, would deter

te situation, charact +h deposit a& may be discovered.

n the valley of Twenty mile don by

economic valu

f the district, particularly i lopment could be carti

mine the

The slopes © h that all mining deve

ercek, are suc Is instead of the more

means of tunne expensive shafts

A problem which future operators e, is a change in the ¢ From the experience of the

in the district wil! probably be 'called upon to fac haracter ov ths ores, necessitating a change in treatment. Daly Reduction Co., in their stamp mill, it smelting of the ores will eventually replace mation and cyanidat It has been found that dept was attained in the mines, \ded Jess and less of 1 content on the amalgamating plates, an:

appears very likely that the processes of amalgajon now in use.

the ore extr ieted yi 1a larger percentage

its gol

went into the concentrates, from which it has to be extracted by

smelting in a blast furnace. There is no doubt, also, 'hat some of to carry pay values cannot

the ores of the district now known

treated at all in th Thus the possibility

Il of these will have to go to

e stamp mill, and a lis

a smelter. of all of the ores ¢ the Jledk

trict being eventually reduced in blast furnaces is not remote Whether this will be done by the erection of sm lters on the ground, or whether the ore= will merely be concentrated and shipped

fuel ean be obtained, and

where, will depend on whether suitable

cheap power developed.

al basin, which covers at least 50 seams ol easily

The Princeton co square miles, is distant only about worked coal. The coal, however, to be capable of producing a firm cohe A coal basin of yet unknown extent, but probably mue lies to the south and west of the st of Hedley. It has not yet beer he grade is better A very fair ind

a

25 miles, and cont rins many

is lignitic, and has not been proved

rent coke suitable for smelting. h smaller than the Princeton area, mouth of about 40 miles we is coal will coke or not, but t furnish a commercial coke. age as the Princeton Nicola valley, and this Altogether

er

Granite creek, shown whether th than a lignite and it may grade of bituminous coal, of the same is being worked in the is distant by wagon road from Iledley about 100 miles. this district is very favourably situated for fuel, and need nes

lack n cheap and const unt whan raikway connexion' are

Granite Cr ek coal,

supply.

1vO GEOLOGICAL SURVEY, CANADA

made. At present, none of this coal is used at Hedley, either for domestic purposes or for the generation of power.

Water-power obtained from, Twentymile creek is the only power now utilized, and this operates the reduction works and haulage, as well as supplying electricity to the town and mines. The horse-power that can be generated from this source is, however, limited, and is not even now equal to the demand. A further supply cannot, therefore, be expected from this source. There is said to be a possibility of developing water-power on the Ashnola river, about 12 or 14 iniles distant in a southerly direction, and also on the Similkameen river above Princeton. A company has been formed at Hedley with the object of using the water of the Similkameen river at this point for power purposes; and very possibly something could be done, but the writer is not competent to offer an opinion on such a scheme. It is certain, however, that when the demand for power arises, some scheme will be devised to meet it, provided the demand is great enough.

Detailed Description Of The Mines And Prospects Nickel Plate Mine.

Location.—The Nickel Plate mine is the best known mine in the Similkameen district, and, like the Sunnyside, is owned by the Yale Mining Company. It was staked in the summer of 1898, hy Wallaston and Arundell, and sold by them to M. K. Rodgers, in 189%. Rodgers was then representing the late Marcus Daly, and acquired the claims in his name, afterwards forming the Yale Mining Company to operate them. The mine is situated on the eastern slope of Nickel Plate mountain about 200 feet below the summit. The outerop of the ore body lies at an elevation of about 5,900 feet above sea-level, or 4,300 feet above the town of Hedley. On this outcrop a large glory hole has been opened up, but the main adit tunnel is 150 feet below.

The slope on which the mine is situated is not steep, and runs down to one of the branches of Eighteenmile creck. It was formerly heavily wooded with spruce, but is now almost bare, except for a second growth of young pine springing up.

Geology.—The Nickel Plate mine lies wholly in the rocks of the Nickel Plate formation. These rocks consist in this part of the formation of massive blue limestone below, passing upward into more im-

Hedley Mining District: Ore Deposits 11

pure siliceous limestones, with which are interbanded some thin beds of fine-grained cherty quartzites. These dip at angles from 20° to 30

to the west, directly into the mcuntain. Numerous sheets and dikes of the white gabbro, locally known as andesite, emanating from stocks of this rock lying on the western slope of the mountain a short distance away, have been intruded into these sedimentary rocks. The majority of these gabbro intrusives are in the form of sheets, and follow the bedding planes of the sedimentary rocks. Some,

however, cut across the bedding planes. Besides the gabbro intru-

sives, there are dikes of various kinds. The most common are hard black dikes ot lamprophyre, which have no uniform strike. Some soft dark green andesite dikes are also present, and one or two keratophyre dikes, locally referred to as quartz porphyry.

The gabbro intrusives, in penetrating the sedimentary rocks, have effected intense contact metamorphism, so that the carbonates of the original rocks have been completely transformed to silicates. This alteration has been greatest in the higher impure limestones. while the massive blue and white limestones below have suffered less. The minerals now found in the highly altered rocks are garnet, epidote. diopside, amphibole, wollastonite, and some axinite, and with these are the sulphides, arsenopyrite, chalcopyrite, pyrrhotite, and

come blende and pyrite.

Character of the Deposit.—The ores of the Nickel Plate, like all the others in the district, are of the contact metamorphie type, and are situated on the contact of a gabbro intrusive with the altered limestones. The gangue is made up of the lime silicates, prine|- pally reddish garnet and green epidote, with subordinate diopside. amphibole, and ealeite. The ore minerals are arsgnopyrita, and some chalcopyrite. pyrrhotite, blende, and pyrite. Seme tetradymite ceeurs at and near the surface. These ore minerals are distributed through the gangue. either in well erystallized individuals, or as filling minute fractures. The values are entirely in goll, whieh appears to be associated. as a rule, with the arsenopyrite. In the ores near the surface considerable gold was visible. but in the present workings, at 150 to 300 fect below tha surface. no gold is visible either with the naked eve or the microscope.

The limits of the ore body that is being mined have been very closely defined by the officials of the Yale Mining Company by diamond drilling, but in an ore body of this character it is hard

192 Geological Survey, Canada

te give a satisfactory idea of its dimeni'e-.3, when its boundaries are not well marked. In shape, the ore body is tabular, dipping at an angle of 25° to the west. Its most clearly defined boundary is on the lower or foot-wall side. Here it rests directly on a sheet of gabbro. At right angles to this foot-wall the ore gradually fades out into low grade rock, so that its boundary on this side is a question of the cost of mining and treatment. Its lateral boundary on the south and west is a curving keratophyre dike, locally known as quartz porphyry. On the east the ore body outcrops at the surface, and on the north it has no definite boundary, and is very irregular in outline.

Taking the boundaries of the ore body as outlined above, it is found that it had originally a greatest length of about 600 feet, as far as known, and a greatest width of about 150 feet. The thickness from the foot-wall to the top of the pay ore was variable. The greatest thickness mined was about 55 feet, but the average is less than half that. The strike of the longer axis is about N 55° W and the dip about 25° to the westward. The greater part of this particular ore body has been already mined out, and it is not known to extend much farther downward.

The ore body does not here follow any one bed of the sedimentary rocks for the whole of its 600 feet, but like the gabbro foot-wall, which cuts diagonally across the bedding planes, it passes from one bed to another in going downward. It does not appear to be closely connected with any system of fissures or fractures, though a wellmarked and strong fracture cuts across the ore body just at its outcrop, and is now seen in the glory hole. This strikes almost north and south. The ore body, at a depth of about 200 feet, is cut also by a small black dyke, which strikes in approximately the same direction as the fracture. This dike is evidently later t. .n the formation of the ore body, and having the same trend as the large fracture, suggests that the fracture also is later than the formation of the ore body.

The gold valuca ure by no means evenly or regularly distributed through the ore body, but they are far more uniform here than in most of the other ore bodies in the district. There is a strong tendency to have the highest values concentrated on the foot-wall. and to die off gradually at right angles to this. At the same time, where the gabbro foot-wall came in contact with the cross-cutting

Se ae

aaa cabana

eae

keratophyre dike and the bl trough, there v values, and some this point.

cubbro foot-wall,

erade that cannot Now

Hedley Mining District: Ore Deposits 193

ack dike, forming a sort of V-shaped

kable concentration of the ore

as found to be a real was taken out ab

of the richest ore in the mine

1, and underneath the

Below the ore body that is now being mine ua

there is known to be another ore body, but ot a be mined profitably. This also rests on a values, and dimensions have

sabbro foot-wall, but its character,

rot been de termined.

Ni xel Plate oe body was first resent the main entrance to the

it No. 8 tunnel, —.. s runs into ore body at a

General Deve lopment.—The mined as a large glory hole. underground workings is by me. the hillside for a distance of 717 feet, entering the point 520 fect from the portal. This point is 150 feet lower than at the glory hole. Dritts have been run

the outcrop of the ore body and on an intermediate level between

on either side on this level, this andthe glory hole. Frem this iwest on the pitch of the ore body. vers, and the roof is supported by pillars of the a few feet near the

level, also, an incline goes down to the north The ore is stoped out, leaving large chaml

ore. No timber whatever is used except for

pertal of the tunnel.

At a point about 150 feet below No. east of it, No. 4 tunnel runs into the hill for a distance of 1,168 feet. This was run with the purpose of cutting the ore body at greater naking this the main adit tunnel, but the ore body

depth, and of n was not found at the expected point, and the tunnel has never been

used for the purpose intended. No. 3 tunnel is lichted by electricity. and rails are laid so that the ore trains run right in and load from the ore shoots. Electric

sd on these trains, but compressed air on the incline and

8 tunnel, and to the north-

power is usc for the drilis and pumps.

Sunnyside Mine.

the Nickel Plate on the

Location.—The Sunnyside mine adjoins south, and like the latter, is owned and operated by the Yale Mining

It was staked in August, 1898, and with the Nickel

Company. ¢, and Copperfield mineral claims, was sold the follow-

Plate, Bulldogs ing year to M. K. Rodgers. It consists of four separate workings.

194 Geological Survey, Canada

which are all located from 250 to 300 feet below the outcrop of the Nickel Plate glory hole, and on either side of the 5,600 ft, contour line. These workings are on the eastern slope of the Nickel Plate mountain, and lie on the line of the electric tramway, which is part of the haulage system connecting the mine with the reduction works at Hedley. The four workings are located on separate ore

bodies, and are referred to as Sunnyside No, 1, Sunny-ide No. 2,

Sunnyside No. 3, and Sunnyside No. 4.

Geology.—The country rocks of the Sunnyside mine belong to the Nickel Plate formation, but are of a lower horizon than those ot the Nickel Plate mine. They belong to the portion of the Nickel Plate formation directly above the massive blue Sunnyside limestone, and consist of bands of blue and white limestone—the latter crystalline—with some siliceous limestones and bands of chert. These dip to the westward at angles from 10° to 25', and show besides some gentle folds with axes running in the same direction (west). The rocks are traversed by several systems of fractures, varying in strike from due west to N 25° E. The most pronounced of these have a bearing of N 85° W and of N 6° W. Gabbro intrusives have everywhere been thrust through the sedimentary rocks in the form of sheets, dikes, and irregular bodies. Besides these. both the country rocks and the ore bodies are cut by small black Jamprophyre dikes and dark greenish andesite dikes.

In their intrusion through the limestones, the gabbro bodies have effected the usual contact metamorphism by alteration of the limestone to diopside, garnet, epidote, amphibole, and quartz. This alteration is naturally greatest in the immediate contact of the gabbro, while a few feet away the limestone has merely become erystalline. This is exemplified in the case of Sunayside No. 3, where the foot-wall is a gabbro intrusive, and the ore body is made up of the sulphides in a gangue of epidote and diopside; while in Sunnyside No. 4, and also in No. 2, there has been less alteration and the original carbonates still remain. Besides the above-mentioned minerals, the contact zone also contains disseminated crystals of arsenopyrite, pyrrhotite, chalcopyrite, blende, and pyrite.

Character of the Deposits.—T.ike the Nickel Plate ore bodies, the ore bodies of the Sunnyside are of the contact metamorphic type and are situated in the zone of contact metamorphism caused by the intrusion of the gabbro bodies.

'hane 0? SNES

Hedley Mining District: Ore Deposit 105

The immediate relation of the ore body on Sunnyside No. 1, to the gabbro, is mot apparent in the workings. '"hese workings, however, are of limited exten', and what ore body is known is situated in limestones, which have been somewhat silicitied by pre- Directly above it and only a few feet away

sumably contact action. which effects strong mineraliza-

however, is a large sheet of gabbro, tion on its contact with the limestones. The extent and eharacter of this ore Lody is not well known, and little has been done on it. Sunnyside No. 2 has so far proved to be the largest of the ore hodies on the Sunnyside mine, and the one which has yielded the greatest amount of ore. It lies entirely in the altered limestones, and is tabular in form and conforms to the bedding of the saiimentary rocks. It dips about 10° to the west, and has a width, as far as is now known, of about 170 feet, and a length of about 220 feet, so that it is roughly oval in shape. The Coot-wall is a bed of white ervstalline limestone, and on the hanging-wall the ore fades out into low t from the foot-wall. On the lower or

grade rock, at a dis-

tance of from 10 to 20 fee western side the boundary is sharply defined by a dark green andesite dike, which strikes north aud south. On the eastern side it outcrops at the surface, where a gabbro dike is also exposed. On the other sides—-the north and south—it gradually ere too low grade to work. The gangue of the ore is composed of the lime silicate minerals—diopside, garnet, amphibole, and epidote— hut these are not so abundantly developed as in the Nickel Plate great deal of calcite yet remains. These minerals

fades away into

mine, and a eecur often in well-defined bands which conform to the original bedding planes of the rock. The ore minerals are arsenopyrite, pyrrhotite, chaleopyrite, and blende, oceurring disseminated through the @angue, or in well-defined bands. The blende, particularly, appears in bands a few inches wide, which are parallel to the bedding planes of the sedimentary rocks. The values are entirely in gold, and are more concentrated in the lower portion of the ore body, near the foot-wall, than in the upper. A strong zone of fracturing the ore body from east to west, and there app2ars and faulting along this line, with About 35 feet above the foot-wall,

sa sheet of gabbro, but the upper

runs through to have been some displacement the upthrow on the south side. and exposed in the glory hole, i limit of the ore body never reaches to this, except perhaps in the elory hole on the surface.

9185—13}

196 Geological Survey, Canada

On Snnnyside No. 3, the conditions are very similar to those on the Nickel Plate. In this case a gabbro intrusive has been thrust into the limestones, effecting strong contact metamorphism, und the ore body rests directly on the gabbro which acts as the feotwall. The gabbro dips at an angle of 40° to the west, while the dip of the altered limestones is 25° in the same direction. The ore body cutcropped on the surface, and has been mined to a depth of 120 feet on the dip. A width of about 25 feet of ore has been mined, and about the same thickness measured at right angles to the footwall. The gangue of the ore is composed largely of diopside, with a lesser amount of garnet, epidote, and calcite. The sulphides are ersenopyrite and pyrrhotite, oceurring either in well-defined crystals

or in bunches. The values, as in all other cases, are not uniformly distributed through the gangue, but are spotted, with, however, a tendency to concentration on the foot-wall. In this ease the only well-defined boundary is the foot-wall, and on all sides there is a

gradual transition into low grade ore.

On Sunnyside No. 4, the geological relations huve not yet been definitely worked out. Here the ore lies in a stratum of limestone not much altered, ane about § feet thick. The limestone is simply erystalline, and shows no tendency to develop the lime silicates. Certain beds, however, associated with the ore stratum, show evidence of metamorphism, in the development of large erystals of quartz, which are embedded in the limestone. The only igneous 10cks apparently immediately connected with the ore body are black Yamprophyre dikes which cut it. The strata are either horizontal, or dip about 10° to the west. fracture zone, in which no pay ore occurs, cuts off the ore body to the west, but it has been proved by diamond drill to be present again on the other side of the fracture zone. The ore consists of disseminated crystals of arsenopyrite. and bunches of pyrrhotite, in a gangue of erystal calcite.

General Development.—The main line of the electric tramway runs directly in front of the entrances to each of the workings. Sunnyside No. 1 has the least amount of work, and has been developed by means of short tunnels aggregating about 200 feet in dis tance. Sunnyside No, 2 was first worked as a large glory hole, immediately adjoining the main tramway. The area of. this glory hole is about 200 feet in length, 75 feet in width, and from 10 to 35 feet in height. The underground workings have three main

Hedley Mining District? Orl Peposits

Nickel Plate Woodland

To accompany Reports Nes 103 and WO? (dividing!

F The Yale Mining Company'S Mines

(Reduced from Company's Plans}

Plan 0

Scale

ifs GEOLOGICAL SURVEY, CANADA

entrances, into each of which rails are laid and the ore cars enter. The south tunnel runs in about 10 fect from the edge of the glory hole to the face, The middle or main entrance is on an incline ot 10°, and runs in toward the west 189 feet. Drifts run off from this to the north, and Jarge chambers are mined out, the roofs of which arc supported by pillars of ore. The greater part of the known ore has already been extracted from this ore hody

On Sunnyside No, 8, an incline of 120 feet runs down on the dip of the ore, and the ears are drawn up by a donkey engine on the surface. These cars dump into an ore bin situated on the main tramway.

Sunnyside No. 4 was also originally 1.ined as a glory hole, bur recently a tunnel has been driven in from the main tramway for a distance of about 240 feet on the ore stratum. The last 60 feet of this is on an ineline of 17°.

Besides the development on their shipping mines the Yale Mining Company, during the summer months of the years 1907 and 1908, have kept two diamond 'drills steadily at work in prospecting their claims for other ore bodies. The cost of this work has been in the neighbourhool of $70,000. At the same time an enormous amount of surface work has been done. Their claims are riddled with pits and open-euts, and nearly every outerop has been eare-

fully sampled.

Production.—Taking the Nickel plate and the Sunnyside mines together, the total production has been given on a previous page as the total production of the whole camp. From 1904 to the close of 1908, the number of tons mined and treated in the mill has heen 153,000, The value per ton of this has varied somewhat, and has perhaps deercased, but its average has heen in the neighbourhood of $15. The extraction from this has heen about #1 less than

the totel assay value.

THE KINGSTON GRoUP.

Location.—-The Kingston group comprises five claims, namely.

the Metropolitan, Kingston, Kingston fraction, King, and Warhorse mineral claims. These are located on the western slope of Nickel Plate mountain, running down to Twentymile creek. and on either side of the Tforsefly gulch. The lower portion of the group lies at an elevation of 3.109 feet, or 1.499 feet above Twenty nile creck:

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' HEDLEY MINING DISTRICT; ORE DEPOSITS Wo

while the upper boundary of the group is about 2,500 feet above the creck. The group is owned by the Kingston Mining Company,

i ate

which has done more prospecting and development work than ans

other company or individual in the camp, with the exception of the Yale Mining Company.

Geology. —The sedimentary rocks of the Kingston group belong tu the upper portion of the Nickel Plate formation, and consist of

limestone beds, with which are interstratitied some quartzite bands

and thin reddish tuffs. All of these beds, however, have been 50 highly altered by intrusions of igneous rocks as to consist now of the lime silicates, garnet, epidote, diopside, and amphibole. They

have a general dip to the southwest of from 15° to 35°, except in

the case of an isolated triangular area on the Metropolitan, where the dip cannot be definitely determined, but appears to be to the

southeast.

The sedimentary rocks are eut off on the north by a bods of ouartz diorite, which runs directly up the mountain side to the east. The quartz diorite also sends off many apophyses into the sedimentary rocks, both as dikes and sheets. Some gabbro dikes are also

present, as well as many diorite porphyries. To the southeast of the group, a large dike of granodiorite,

sedimentary rocks from the main body of the Nickel Plate forma-

500 fect wide, separates the

tion. and extends southw ard to the Similkameen river.

As all the ores of the district are found only in the sedimentary rocks, and so far, only in those of the Nickel Plate formation, the area of sedimentary rocks on each group of claims is important. On this group there are two distinct areas separated from each other by a tongue of diorite running down to the southwest from the main body. The smaller of these sedimentary areas lies on the Metropolitan claim, and is triangular in shape, with each side ot the triangle from 800 to 1,000 feet in length. It is surrounded on two sides by diorite, and on the third by granodiorite. The whole area is very highly metamorphosed, and cut wita dikes cf porphyritic Qiorite and gabbro. From the regularity of its strike, it is to be expected that the contact of granodiorite and the sedimen's vill be an almost vertical one. On the other hand, judging by the natur of its intrusion, and the great amount of contact metamorphism, st is likely that the diorite contact will be a plunging one, and it may he found to dip underneath the sediments so as to eventually

cut them out altogether in depth.

fide:

Shae

seats

Geologica Survey, Canada

rhe larger area sedimentary rocks lies alove the stuailer, ated

© southeast et it. It, also, is bounded on the southwe nodiorite, and on tae north by diorite, and i the form of a \-shop wd body, widening to the southea t, as it goes up the side of the? ntain. This, also, is cut by a great many sheet 1 dikes

yritie diorite and g bbro, as well as some smaller dikes of nd lamprophyre, which are intrusive both into the sedi-

into the granodiorite and diorite ma

r of the Deposits Tine ore deposits the Kingston be divided into two groups—those containin copper ag al valuable metal, and those containing goki. Ou each

pment work has been done, but no or ip to date,

iwposits have been exposed by wo: ings principally

( the Claim. They lie in what were iginal limestone is at a he contact of the rocks of the diorite gabbro eomex, Which hi altered the limestone to the fam iar rock comed of garnet nidote, diop e, and amphibole, The limestones

e interbedded with some siliceous bands, and they dip at an angle

ubout 30° to the west. The gangue of the ores is the lime silic ite

minerals, and the ore minet themselves are chaleopyrite, pyrrhotite, arsenopyrite, and galena. These ar tattered through the ingue in varying proportions, with pyrrhotite usually in greatest proportion, The chief values that have been obtained are in eopper, hut this is supplemented by some values in gold and silver. The highest values in silver obtained in tho whole camp are got from this ore, which frequently gives 8 to 10 ounces to the ton. An average sample of the ore on the dump of the Warhorse ill give shout 6 per cent of copper. The extent of the ore body on the Warhorse has not been defined, but the evelopment work has shown outerop of an ore body, of considerable economie importance,

A similar oceurrenee of copper ore js known on the Kingston mineral elaim, 800 feet helow the Warhorse, but here again, ¢! extent of the ore hody has not been defined

Gold ores in payable quantities oeeur on tha Kingston and Metropolitan mineral claims, under similar conditions to the copper ores, While each of these occurrences is of contact metamorphie

origin, and is found in the zone of contact etamorphism indueed

hy the intrusion of the diorite. the area and general outlines of the

Se ———

Hidioeth' ee abbeachatestenen tt A veeRR LEE,

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HEDLEY MINING DISTRICT! ORE DEPOsTLS Zot

ore bodies have not been detinit determined, Most of the work has

beet done on the Kingston claim. Here, gold values from §5 to #20 have been obtained im considerable quantity on the surface, im the -cdimentary rocks, within 100 feet of the contaet of the diorite. In one of the most likely places, the outerop of a payable ore body has been found in the sedimentary rocks alongside a black lamprophyre dike which strikes north and south across the side f the hill. This ere body has been explored by a shaft 14 feet deep, and found to be payable to the bottom, but a tunnel run in to eut this ore body, ata depth of about 50 feet, failed to show any pay ore at that depth, perhaps beeause the ore body dips at a low angle to the southwest, and passes over the tunnel. Surface cuts in the same neighbourhood show ore occurring in payable quantities, but it remains to be proved where these ores go to, and whether they are payable at

greater depths.

On the Metropolitan mineral claim, which covers the triang area of sedimentary rocks already referred to, some very good results and high values have been obtained by reeent work, The gold ores here are also of contact me taiorphie origin, and are associated with the gabbro and diorite intrusives, within 200 feet of the main contact of diorite. The sedimentary rocks are here very highly altered indeed, and are made up of reddish and greenish garnet, cpidote, and diopside. No well-defined bedding planes ean be made out. but the rock is frequently sheared and traversed hy fissures and faults. Surface ores on this claim give assays as high as $100 to the ton, and oxidation does not extend downward more than a few s. In fact, most of the outerops are quite unaffected by oxida-

tion. At a depth of about 59 feet from the surface an ore body. with a greatest width of 14 feet, was discovered, dipping at a low angle to the southeast. This lies in the metamor phosed sedimentary rocks on either side of a high!s altered zone of rock, 1 to 3 feet wide. which appears to be a dike of rhyolite. The ore minerals are principally arsenopyrite, and some chaleopyrite, occurring in a gangue of lime silicates, and much free gold can be scen. The gold is in small thin flakes apparently following minute fracture planes, and is clearly of a secondary nature, that is. the result of percolating goldhearing solutions of probably metecrie origin, The values are hy no means evenly distributed, but are, on the contrary, very erratic, co that essays give variable results. Results as high as £200 to the

ton have been obtained in portions of the workings, While the gold

202 Geological Survey, Canada

is generally fuund in small fracture planes, some of the zones of fracturing are quite barren, indicating that this fracturing is of later date than the ore formation.

The ore body has no detinite walls, so that its exploration is difficult. The extent of this ore body has not yet been determined, but work is still in progress, and it is hoped that the results will be highly satisfactory.

General Development.—More exploratory work has been done on the Kingston group than on any other group, with the exception of the Yale Mining Company's properties. Work has been in progress for nearly ten years, and considerably over $50,000 has been expended. This work has been confined to the Warhorse, Kingston, and Metropolitan mineral claims. On the Warhorse some 200 feet of tunnelling and much surface work has been done. On the Kingston there are two main tunnels. The upper one runs in 80 feet to the cast. with drifts of 60 feet on either side to the north and south. The lower tunnel runs in about 110 feet, with a drift of 30 feet to the north. Besides this, shallow prospect shafts have been sunk, and much stripping of the surface has been done. On the Metropolitan, a shaft has been sunk 58 feet. with drifts at the bottom, to the north and south, of 20 feet each. Below the shaft. 120 feet of drifts and tunnels have been run. On the surfaee, also, much

stripping of the rock has been done. No ore has yet been shipped.

Florence Group.

The Florence group of claims consists of the Florenee, Whale. 3ullon Beek, Florence fraction. Little Pittsburg, Zerust and Eagles' Nest, seven claims in all, situated in the northern part of the district, and on either side of Bradshaw canon. They lie on the eastern side of Twentymile ereck, and in the angle formed by the bend in the valley of that stream. The lower limit of the group reaches almost to Twentymile ereck, while the upper limit is on the top of the Aberdeen ridge, at an elevation of 5,500 feet ubove sea-level,

The group covers, on the eastern side of Bradshaw canon, some rocks of the Red Mountain formation, and ca the western side a larger area of the Aberdeen formation. Through the centre and southern portions of the group runs a broad strip of the Nickel

Hedley Mining District: Ore Deposits 203

Yate formation, which widens toward the base of the canon, and connects with the main bedy of these rocks on Nickel Plate mountain.

The strongest and most marked fault in the district runs directly through this group of claims, and down the Bradshaw canon. An earlier fault to the west of the cafion has displaced the rocks ef the Nickel Plate formation, so that they are first upthrown on the western side, causing them to reach the summit of the mountain. Then the Bradshaw fault has downthrown them on the same side, sv as to bring the Red Mountain formation almost to the foot of the 'ajion, with the Nickel Plate formation hidden beneath it altogether.

Dikes of diorite and miea diorite have invaded the older rocks in several places and sheets of gabbro have also been thrust into them. Besides these intrusive rocks, there are smaller dikes of andesite, and of the so-called quartz porphyry, which cut all the above-mentioned rocks.

The development work has been largely by tunnels and much surface work, and some good values have been obtained in con-

nexion with the gabbro sheets.

Iumming Bird Group,

The Humming Bird group, owned by J. J. Marks and some others, consists of eight claims sit)ated in the northeast corner of the district, and to the west of Lookout mountain. The surface rocks of the group are entirely those of the Red Mountain formation, overlying at some depth the Nickel Plate formation. They dip at moderate angles ta the west, and are intruded by dikes of diorite and some gabbro.

Considerable development has been done on the group by surface euts, shafts, and tunnels. Four diamond drill holes were als sunk, aggregating almost 2,000 feet, but no information was available as to the results obtained.

Other prospects in the camp on which a certain amount of development work has been done are the Windfall group, Iving in the Windfall caiion, the Fairy Queen group at Central station, and certain claims owned by Geo. Cahill and Dunean Woods.

Glological Survey, Canada

Appendix.

Certain mining districts tributary to the. Hedley district, but not included in country covered by the gedlogical map, were cursorily examined during the course of the work. These districts aze the Golden Zone camp, locally known as the Quartz camp, and the Wenry Creek district, each of which is worthy of mention as having had considerable work done in it, and of having been the cause of some local excitement.

The Golden Zone Camp.

Location.—The camp was located in the year 1900 by Messrs. Murphy, Brodhegan, and Marks, and consists at present of four surveyed and Crown granted mineral claims. These claims are the Silver Bell, Golden Zone, B.C., and Irish Boy. The camp lies at an elevation of about 5,900 feet above sea-level, and is situated on the head waters of Twentymile creck between its east and north forks, A wagon road 11 miles in length connects it with Hedley, and was completed in 1908. This wagon road also connects with Penticton, which is distant about 30 miles. The country here is thickly wooded, but the original timber has been burnt off and is replaced by a second growth of young pine. Exposures of rock are not numerous, but there is a thin mantle of drift over all.

Geology—The oldest rocks are of sedimentary origin, and are probably of Carboniferous age, similar to the Hedley sediments. No fossils, however, have been found in them. They consist of limestones, quartzites, and tuffs, all of which have been considerably metamorphosed by later igneous intrusions. They dip at an angle of 30° to the southwest. These contain interbedded sheets of diorite, and some gabbro, showing a strong similarity to the rocks of the Hedley district.

Intrusive into these sedimentary rocks, and found only on the

two western claims, is a body of fine-grained micaceous granite. This weathers very readily, so that a fresh sample is diffeult to obtain. It consists of feldspar, quartz. and hornblende, und much

Hedley Mining District: Ore Deposits 205

biotite. It has undergone some metamorphism, probably from orogenic disturbances, so that a gneissic structure is frequently developed in it. On its contact with the sediments it becomes finer in grain, and more acid in composition.

Lying to the south of the fine-grained granite, and the sediments, is a coarse-grained pinkish granite of apparently batholithie proportions. This appears to be later in age than the fine grained granite, for though the actual contact was not found exposed, it appears to hold inclusions of the fine-grained granite, and to send off apophyses into it. It consists of large crystals of pink and white feldspar, quartz, mica, and some black hornblende, all so highly developed as to indicate erystallization under conditions of considerable time and pressure.

Intrusive into all of the above rocks, and lying in the southieastern part of the district, is a body of granite pozphyry of dike like proportions. This has an average width of about 1,090 feet, and lies between the coarse-grained granite and the sedimentary rocks, and in direct contact with each. Into each of these rocks it sends off apophyses. Its constituents in the centre of the mass are phenocrysts of quartz, feldspar, and biotite, in a fine-grained acid ground-mass. The composition remains unchanged southward, to the granite contact; but on the north, on approaching the sediments it undergoes a change. Here it becomes more acid, the biotite disappears, and the only phenocrysts are glassy quartz, which are embedded in a pinkish feldspathic ground-mass. The metamorphic action on the sediments has been to change them to a dense grey siliceous rock, in which some mineralization has taken place, as shown by crystals of arsenopyrite. No such mine ralization is apparent on the granite contacts with this rock. Some shearing, and the formation of small fractures has taken place in the granite porphyry.

Character of the Deposit.—The claims have been staked on a well-defined and persistent quartz vein, which can be traced in an east and west direction for over 1,200 feet. This vein cuts both the fine-grained granite and the sediments. In the former, it occupies a strony fissure, varying in width from 2 to 4 feet, but on passing into the sediments it appears to split up into four or five smaller

veins.

206 Geolugical Survey, Canada

The lead is a true tissue and frequently shows a well marked ribbon structure, due probably to the tilling of an open space. 'The walls are clean and smooth, and often show slickensiding. The dip of the vein is about 90°.

The gangue is a hard white quartz, and the ore minerals oceurring in this are pyrite, arsenopyrite, blende, and chalcopyrite. On the surface the quartz is gcnerally honey-combed, on account of the weathering out of the sulphides. Below the zone of oxidation, it is seen that the sulphides appear in well crystallized individuals in the gangue, as well as filling minute fractures of a later date than the crystallized individuals. The sulphides filling the fracture planes are, as a rule, arsenopyrite and pyrite.

The age of the quartz veins is rather problematical, but they are probably later than the intrusion of the quartz prophyry, and may be genetically connected with it as an after effect. Undoubtedly orogenic movements have taken place both before and after the formation of the quarts vein, for the vein is slightly displaced by a fracture to the wes\, so recent that it still preserves its topographic expre®;sion.

The values are in gold as well as some silver, and are said to be higher in the sedimentary rocks than in the granite. On panning some of the decomposed ore on the surface, a number of very fine colours of gold are obtained among the arsenopyrite concentrates in the bottom of the pan. No samples were taken for assay, though the results obtained by the owners and others are said to be very satisfactory indeed.

General Development.—The property is equipped with a five staap mill, which was hauled in on sleighs and installed in 1998, No serious milling has yet been attempted, however the failure of the water supply.

, ON account of

The development work consists of a shaft sunk to a depth of 115 feet on the vein near the mill. A second shaft, 250 feet to the west, is down 47 feet on the vein. Besides these, several smal] pits have been sunk at intervals on the vein, at a distance of 1,000 feet from the main shaft. Numerous epen-euts and trenches have also been made across the veins, especially in the neighbourhood of the contact of the sedimentary rocks with the fine-grained granite,

Pr veerene A a RAS Saha A ES BETES a SPR AT ee Or

Hedley Mining District! Ore Deposits 207 The Henry Creek District.

Localion.—Henry ereek is a small stream entering the Similkameen riyer from the south about two miles above the town of Iedley. A group of five claims now owned by the Pollock Mines Company was first staked on this creek in 1900. These are now surveyed and Crown granted, aud are called the Martin, Dai-y, Maple Leaf, Minnehaha, and Pine Knot. They lie on both sides ot Ilenry ercek. The lower boundary of the group is at an elevation ot 400 feet above the Similkameen river, and the upper limit is 2,000 fect above that stream. Access to the workings, which are 900 feet above tle river, is by means of a pack trail. The grade of the Great Northern railway crosses the mouth of Ilenry creek 300 feet below the lower boundary of the group.

Geology.—The country rocl of the district consists of black limestones aud argillites, and some voleanie tutis and breccias interbedded together in thin beds not more than 1 foot in thickuess, They belong to a somewhat higher horizon than the rocks of the IIedley district, but are apparently conformable with them, They have been subjected to strong orogenic movements, and now dip at very high angles, and strike about north and south, Fissures have been developed in these rocks in a north and south direction, in a most marked degree, while in directions transverse to this they are traversed by numerous minute fractures.

An irregular body of diorite, apparently identical with the Hedley diorite, is intrusive into the sedimentary rocks, This passes through the claims in an east and west direction, attaining its greatest development in the centre of the group, where it has a width of about 1,400 feet. The contact with the sedimentary rocks is very irreeular, and apophyses of the diorite project out into the sedimentary rocks, cutting across the strike of the beds.

Both the diorite and the sedimentary rocks are cut by soft greenish dikes 0° an andesitic character, whieh str north and south abaut parallel to the strike of the sedimentary 'ks. Other dikes somewhat similar in appearance, but of a more siliceous nature, also cut the sedimentary rocks, and probably also the diorite.

Character of the Deposits.—The deposits of the Henry Creek district are fissure veins lying in the sedimentary rocks in the neigh-

20s GEOLOGICAL SURVEY, CANADA

bourhood of the diorite contact. The sedimentary rocks are everywhere traversed by minute fractures which contain some pyrite and arsenopyrite, and which have no detinite trend. The fissures, however, on which the work has Leen done, are strong and well-defined, and have in general a north and south strike.

The main workings of the group lic at an elevation of 900 feet above the Similkameen river, and are located on well-defined fissure, which has been traced for at least 500 feet, The width of this is not constant, but varies from 2 feet up to 12 or 14 feet, with an average of about 5 feet. The gangue which contains the ore minerals is both quartz and ealeite, and these cement together fragments of the country rock with which the fissure is full. The ore minerals are largely arsenopyrite with some pyrite, which are

found in the quartz and calcite, as well as in the small fracture planes in the country rock. The values here are chielly in gold, and in the decomposed outcrop of the vein free gold was easily obtained

by panning.

The upper workings of this group He at an elevation of 1.400 feet above the Similkameen river. These also are located on quartz veins, which, however, cut the diorite as well as the sedimentary recks. The most persistent of these veins has been traced on the surface for a distance of 500 feet in a north and south direction. and it has a dip of about 45° to the west. Another vein lies almost flat, but is only a few inches wide. The gangue is a white quartz. which carries as ore minerals, arsenopyrite, pyrite, and some galena. The values here are also chiefly in gold, with some silver. In places they were found to be high, but were not uniform. The best results were obtained in the lower workings.

General Development.—Considerable work has been done on this group of claims at different times, but this has now been discontinued. On the upper quartz veins, the work consists largely of a series of open-cut and shallow pits. A tunnel, also, has been run in on the flat lying lead for a distance of over 100 feet.

On the lower workings, there are two inclined shafts at the north end near the diorite contact. One dips 60° to the west, and is down 60 feet, with a cross-cut at the bottom of 30 feet; the other dips 50° to the west. and is down 55 feet. There are also five tunnels running westward into the side of the mountain. The longest of these is 148 feet in length, and at the time of exemination had two

Hedley Mining Districts Ore Deposets 200

drifts along the vein to the north and south, the one 30 feet in length, and the other 64 feet. Another tunnel above the longer one

is 60 fect in length. Besides these there are three shorter tunnels, all cutting the main lead at different points.

Index

Pace.

Aberdeen epoch.. COURSE eee Ee IES oo ee ee haat eee Aberdeen formation... .. . rare ott ak 46, 66, 72, 166, 167 os My no important ore ; bodies dismovered BD ss ce eu hee Agriculture in the district... 6. 66.6 ce ce ee ee te ee ee ce ee ee ee ee 40 AVR 3s Acc cd 456 Fa 0k $C Rese OS OM ACU RHE HEISE KE Re eR Les arg Rae INCL L ht Peet are Mere WiC ato Ree geek rec TTC ye i Rec CA 146 Analysis—amphibole.. .. 2. 06 ce ce ce ce oe oe ne Oe oe wee ee oe ne ee oe 146 e PRBOEG eens ea. he eee ES) WS ie vasa. ales ee ND ase . 83, 84

is granodiorite.. 0. 06 2s ce ee ce oe oe oe oe oe oe oe te ne . 96, 97 " Hedley pyroxene.. 0. 0. 66 ee ce ce ee ee ee ne oe te ne ee oe 82 "

GUREtE GIOVEO. sess cee s 35 oh 2 test Cer Ce die se me ea ino" 78 areal tan ese eee ee eee OE ORDA ET Ete Rarer ne rete hee AMSG s. co ve ce terse es Gn we abr cei gs ee Fae ras nee cere sir eectan es 148 ADPONUIE eee Guceu centr Shah 2 wee oes viel ob ienuemss nem etnies es 204 Arsenopyrite. .26, 65, 80, 55, 86, 130, 182, 136, 138, 139, 141, 147, 152, 153, 205, 208 mbUndaNee Of lcs ss vol Fe Ge eoUee, Os Fen Seles ekvanhaie 3 Le associated with BOG in ae ae eo kee oe eee . 140, 174, 178

os s MULGOD ei con oe cece puna teensy cent Oe eee Assays of drill cores.. .. 2. 21 ce ce ce ce ee oe oe oe oe ne ee te oe te 163 PBT ALT eee Meg Fee EU THO COMET ali, Pee Cth CCS RE tN aie 148

B Banerman, Mr., notes on district.. .. .. reictencs ti lk Barrell, —, U. 8. Geol. Survey, theory of mapmalie eecoianes Repeal Bibliography... .2.c< so ance wei se Gules Eee AON ee Oe we vei eer eae ee 20 Bradshaw -fadlts< ci ce ce yaed esc cste a 0) ne Be Gee ee Beh a . 118, 114 Bulldog mineral Claim... 6. 6 6s ee ee ce ee ee ee ee ee ne ees .. 139, 141 Bullon: Heck C1 iiss. 65 se Fo se) oe eleva oo welew cde ne Fs Ch, cil wel ae 202

'ache Creek groups. 2. 5 62 0 ee oe oe ce oe oe ce ce ne oe 6% 66; 24; 72

" Deasaighie: Ae ear ae ere eee an TE Pe 'ahill, Geo., owner of claims, Humming Bird group... 6. ++ ++ +e +: 203 aleite.< ss i: ele ea eR eS ee ve ESRD RGR Oe

original EAE of ore eau. re uiiiaee nericns ater ee Cartwright, C. E., assistance of acknowledy Ber eben ee Ler iri ANE mee Cascade Mountain system... .. -. 6+ ee ee oe oe ce oe we oe ne oe ..29, 30, 31 Gi inticiyayd s Utne ne co) oan Gg ie Ole Beare Onering a0! Ob cere op xo. oc ..141, 150, 152 Ghiorit@.<) De ee tres ere eae mnt COL eon itera MET cy Climate of district. zs IE ea rE ee Climax bluff, centre of rae workable. ore 5 bodies, eee ere terete, eS:

cafion, gaiena in.. oy en are a peers ome moar LT

GLBTA eich. asico de Pee LG EE SPIN RTE Lott vgn a 180s, I Ae an ST UE 7

Cobalt, . CUES, Ge cdR ex eel eeae vee demae es

Connor, M. F., analysis of quarts dierite by., " xabbro by..

granodiorite by,

Copper.. , Lahsrahes Cleft claim.. PPLMEN eR Cae heeeine. ce

World mineral claim, amphibole at.. ..

Coulthard, Mr., early claim staked by.. ., .,

"

D

Daisy claim.. .. .. .. ., Daly, Marcus,, .. .

Prof. R. A., acknowledgments te.. 2... ., ee paper by.. .. .. eC aes Similkameen Valley formation

"

study of igneous rocks aT IAEA Ser ae rene at ee

theory of magmatic Daly Reduction Co... .. .

stoping,

average values of ore, . description of plant.. .. .. Dawson, G, M., address of, referred to.. .. .,

"

views of, referred to..

Dewdney, Hon. E., first claims SEBERRU TOP ecetoan serg lining en Ae

Dawdmey trails. 55 bs cs ese ee Diamond drilling, use of by Yale

Mining (o.. .. Dike rocks., wb: 18isy ere bees: Diorite-gabbro, .

Kagles' Nest claim... , Kighteenmile creek... 2. 0... Epidote., .. ..

Erythrite.. .

Evans, H. F., articles by, in Mining World.. 2... 0. 0... a

Exchange tunnel... 0... 0... ik we bE Oe as

Fairy Queen group... .. .. BElGRDOP 2". 6 ac aa en Gass le, Vissures in relation to ore bodies.. Pores kis ta che tance Florence claim..

o fraction claim.. BlOUNS cess ce, Fossils... ..

characteristically lac king in Cache Creek g Fuel for smelting: .. .. ..4..<: 0 ex .. Ro" ON, Ruse See a

Survey, Canada

130, 141, 170, 2

report of, on district... .. .. 0) 4. 56 ae a ba see nee

ee + DSS, 191, Humming Bird group..

Pace. + 138, 143 78 ow &

+ te S6F 17, 190 Iso ' 20 18, 70 . 2B 196, 198 "so oe ce 9B os ce oe 105 +72, 166

on

8, 19, 181, 186,

. - Bt, 32, 34,

er ek Oe

roup..

Index 2138

Pace. fiahona (See itso Lead... es ae ee Par Cy vot Ty .. 161, 208

Giangue minerals, paragenest* OO cat cee eet ' c¥utie: weed . 153 relation of to ore mineral 8 ea - . Ui

Garnets.. .. Rarer ae 0% rere ee eT 50, 147 Geologie history of diatrict.. .. - Be Nee Pee eh We fae . 8 summary of,. .. ei era Geological formations, tatste of... +. a a Be ob v8 ar ee ers 42 Ceology, economic.. .. ee re ees Pe ee aE ee Perey ee ee tS 130

i Golden Zone COMP... ce ice ce ce re re re es Spe pee Mei aes "i Henry Creek district ta Ae BA Ge ee gee ema te ee Ee 207 Kingston group. . ce ce ee ee ee ree ioe da a tere .. 199 Nickel Plate mime... 6. 6) er res ' DRA SPER: 3 of the district... 6. 61 ee ee ee ee nes Per ate ™ Sunnyside mine... 6. 6 ee re ce te ees Se. ne Setar See Glacial deposlte..c2 ce oo en en sees ee te tees MAS eerie Glaciation, RESIN ae cee ee _.39, 86, 35, 36, 38, 119, 124, 125, 128 Cold. 11, 15, 17, 19, 24, 26, 27, 118, 150, 132, 15, 1), 164, 165, 170, 172, 173, 174, 191, 196, 200, 201, 206, 208 sssociated with chaloopyrite.. .. .- cece ee se meen sees ee ee te 141 s S pyrrhotite... 6. ce s6 oe ne oe ee ee ee nee i ee x GRE PRAG REE see, eerira sd Remick tse eet ee ORNS 138 "production of, at Nickel Plate and Sunnyside mines.. ss s+ + 198 Giniitoal BGNG CRUE Deore ecens cites Se eertin ox eer stn See Pee SE 204 equipment and development atic oy iixesas An an oe (Oe GCeenoint tO. wo ai ean BY ee ee Ce aD orice SS ERS Ieee cal weleal kone eae Great Northern railway... .. .. ee LRN ae mas hy eer terig yr) A 207 Giwiilim, Prof., test of splialerite.. 00 cs cs sss ce en oe ee on ne on ee 142

H

Eaves; A iOrs caer ceca sae he ees coed ok a Paes Care tie BES Hedley district, bulletins and papers on... ies: Seed Sicec, Cia

development of... - we AR nec tales: Fee early claims staked in.. 6. 6+ ce ve ce ee re ee te te 7 ec geology complicated... 6. ++ s+ + ee LAG ate ee bg gold only FPOAGGE ihins to eis tries remy Shit nes St 34 ey position ef, e Re. re re 982, 15 " status and future possibilities... 6.06. 26 ee re sess 184 "

unique character of ore deposits... 66 ee ee ee 11, 178 Hedley sheet, columnar section of rocks of... 66 6. e+ +: Se ean ae 47

me PSU ore et a ee are eee eee MED Enna eee Mee OR INES ar 18 Santry (reals GiathiObser ces s1es Seneean iy snetiee ee ese tps satis 204, 207 ee developarent aie cer. os aa Go ee Moe we Seles es 208 Fosaniten TWOuntaity TANGEss 66) 7cs, Cees tr Ae se) es ew se cs Pan EN Hunvining BiCd groupie. os ae gees saree eee e sper ne Fe Me etcne 1 203

Tyneous 1 ks of district... Seles S844 ie ee ke oe EO. WH OH EF AF HE 1s s relation of, to ore hhodies.. 6. 6. Ser ets eo A

THtPuRiOneRMterorinaiOl sy arc< seein ee cer retort o ie eens 122

4 Ch Obama

Irish Boy plain fron ore

percentage of, in sphal Irrigation,

Johnston, R. A A., analysis of ¢ Jones, G. P

conttivance for du

King claim

Kingston claim

fraction claim group of claims limestone,, ,

mineral claim, apatity Mining Co

Tead. (See Galena )

Lead, associated with tetradymite Ligsite...< ee

Limonite,, an ee edn% Lindgren, W., genesis of ore d Little Pittsburg claim... zs Lode mining, Cariboo district... Lookout claim.,

Magnetite, , DRA Ce RL Se Maple Leaf claim.. peg

Mertin claim,. rear Metropolitan ciaim Mica (See Sericite), Milling, methods of... Peciectery Minerals of the district, list of... Mining, cost Of, ;

methods Pane Minnehaha claim... Molvbdenite. , Mound claim

Nickel, , Hele as eit! Plate epoch,., formation

all know nh ¢

made up of calcite

Marks, J. J., owner of Humming

Murphy, Brodhegan and Marks, Golden Zone catup loc

ey CAN

rite,, amphibole, ping eas

K

it

Lird group..

N

; 44, 46, 54, ve bodies contained in

tothe 14, 1b. 17, 19 rt. E33, IB? 149, 1o2, 158, 19,

173, 180

4, 34,

ated by

'2, 165, 166, 167, 171

Paar AM

. 6, 6S ite

Po 17, 198 17, 198, 202 19s

' ov - 88 56, 57, 121, 170 ltt

Me

. 186, 199

lit

. 80, 110, 144 eo oe 207

' 207

20i, 202

181, 18s

aroun 204

oe 138, 143

isi, 169,

154, 186, 18:

Index

icke! Plate mittee, axer t ehaleopyrite in ' ee 8 1th, . + detailed deseript y of F epidote at a is erythrite at feldspar in j ' pyrite at / " phelness of ot ry ephuateriie it 142, : re " tetrodyimite found tp , ' es ; pretitebae 10 wr charocter of cart cobalt tt pyerl i ! hebesions of oO Ohana trountaat wy OO, BE, be Ore bad relation to country rocks...) ee ares ae a ee ies of occurrence,, hep : a cter Y distribution f we 48 t via t t . ia Ss r ¥ minerals bes ' oe 8 p Persistence of ore bodies.. Tore tk Pine Knot claim... .. rere Oat Placer geld, Similkeameoen rivet... aa: Placer mining, Cartboo distort Rw ak Perera : none in Hedley distriet.. 6. ++ +: Pisteesas os. an ee ee ee ier eters es ;

Pottock Mines Cos. ovo os se er ne es eee es Precipitation... 6. s+ ss se se se te ; contrast between Hedley

and Nickel Plate

Prineotor OU Ots scones cr cases) So kus are te oe es " coal basin net far from mines. Pyrite.. Hey lee a eNOMCC, Gotta Ts OU a aa

Byroxeli@entscts.yecnsecin nner so? sie sane x9. wa ae

Pyrehotite.. a. ccs ce takes ee ee re se tes

artes os. es: ot voce ew ares ERR ae oa ne ee : sf camp (See Golden Zone). 5 - veing, absence of.. -- S ghmaw in ai ial woes mL ews Shel e 4 Quaternary deposits... .. -. es er rere tee Rei Ril ss 46 ws eet

ee PEDLER,

216 Geological Survey, Canada

Pace.

Red Mountain epoch.. .. .. ., Sa rele ate Red Mountain formation..

ear 120 +45, 46, 61, 72, 166

iron compounds at..

P RLS ul tind pena 144 we # ho important ore bodies discovered in,. .. 134 " "

Dyrenotitenitc, ae ee Neh ba, Sos ee Redtop epoch.. .. Sieh Hsin SiSiutishaheriareh Where Taipreter eae acini eee gO Redtop formation.. .. potatoe reer eee oe 43, 46, 49, 72, 165, 166

a ho important ore bodies discovered in... .. 2. 134 Reduction works in Similkameen valley... .. ., Seale soacine tre streets oT NE Reichenstein (Germany) ores similar to those at Hedley.. .. .. 2... 178 Reinecke, LeOpolas oe ain se oho DCN OOO CN Ga aie roanc sere ee 0 Robertson, W. F., provincial mineralogist, B.C., VIRICCOL seen gecct C19 Rodgers, M. K., connection with camp.. .. .. 0... se ee oe oe 0617, 190, 193 Rollo claim.. .. .. .. .. .. SIP SPLRS tH, Were eels Seale vel vie cereeieeas, ULE Ross, F. A., presence of platinum referred to.. .. araats ee 137

S Sedimentary rocks.. .. 2... SSNieity Sister ed Fiver sles ee ice seme. LOG Betiontes. co Adc sete Staten ESN Gel wy weinees ee we cee 16O Shuswap series.. .. ., DONE watery ee tiles ee ee se, M1

DIVER. ii ca eyes, MAAS SPS ene ++ +26, 69, 137, 110, 174, 200, 206, 208 : associated with chalcopyrite.. .. CA SUNUSY wots sie anal teal e tS PRERNGtICG Te ere ee EGON ten pee ett

sphaleriter. 4. sce ee aie pa) wees daey ae 142 Silver Bell claim.. .. .. .. Pree e Le Seen ce Fen eielsis ined estas Sater gacees rye Similkameen river... Sauces Nokes slemro inca net's Eat street eon an ete . 30, 31, 33, 39 ee valley, how formed.. .. .. SOK RE Gia ore at ora et Raper pt i reduction works in.. .. SASS BS ceances ie ete vee Lae Skagit mountain PIER BS hose ales aaalogh s eeatcisto va atm realty: o Smelter at Everett, Wash.. .. .. Sel # Sastre ssieies. col mam sreyey esd OS IRS Smith, G.O., gabbro from Beverley Crook, Wash., described DY cOe Se rocks lithologically similar to Cache Creek group described by.. ES Ee RCE. OS a AS VO cae TRA mie 71 Sphalerite, (See also WANG tt sea eee ae BOTS SOE Rr eariey capes CY Ug fy an Fa) Stevenson limestone,. mews Betas UO aeS Eee Ce Ie etscrins ey yen Yea i"

" "

and calcite... .. i; .: .. DOSES Riera! ity hier Oe Stream deposits.. .. .. .. Ba a ae MI POU IG Bits olen ese cero Aoki it

Striped mountain... .. Sunb -C letneved aren vera ne eu ae - .18, 50

Sulphuretted hydrogen, emission of from rocks... as, tees ee Sa 8 52

Sunnyside limestone... gO oar aes eerie (shh 144, 166, 170 ae mine, .14, 24, 54, 133, 137, 149, 153, 158, 168, 169, 173, 180, 184,

186, 188

me "amphibole at.. .. PON RLU CS LOGe Once nee eee Yc

se "assays of dril! CODER er ssi Fe sislcals ah aiee ekg Oa. eee ss 168

Ke "chalcopyrite in.. Beuisteataiel ate Te cee acieries © 1 hes C31

fe "character of UBT eR Ge erecta ee he een Sea 168

Se "detailed description of... .. .. Wal ee lee tern eran 199

limonite in... .. DOERR ACen een Syren ey Ee GA ees pH

sera

' ;

PRRARSRIRREL Sees ae een ConmMeT eam eceMesteNRIDS eases eon

Index Ott

Paae.

Sunnyside mine, bickel found at.. 138 Me "pyrrhotite in. . te

ee sphalerite at. V4

- — wollastomite at.. 146

ore body, dimensions Or. 1d

T

'Temperature, (Yee Climate.).. Ri) Tetradsimite.. See arie yt 'Thinber 39, 190, 201 Ito

Vitanite.. ~-a8, 124

Topography... Pewee 15, 185, 204, 207

Transportation.

'Tulameen river. a eS a Raat at ae 0 Twenty mile creek... ae .. a0, 31, 32, 38, 87, 125, 128, 150, De i. early discovery of gold on... Ww s mmolybdenite on. Iw bi " sphalerite on.. 142 " wuter-power.. [sz Volcanic derivation. . 119, 120, 121, We Ww Wallaston and Arundell, Nickel Plate mine staked by... 0. s+ #6 0 190 Warhorse mineral claim.. .. -. 6) e+) s+ ..17, 141, 198, 200, 202 a zi amphibole in.. 147 si copper ores in.. 170 Me lg pyrrhotite in.. ©. 6. 6. ee: a gtsts 142 Warren, Prof. C. H., acknowledgments to.. .. +. 5 i) "3 a tetradymite identified by... - Pe cise SO Water-power, Ashnola river.. Par 190 ws Similkameen river. . . 89, 190 a Twentymile creek.. ney aoe

Water supply... . 88, Ist ATT, 1S

Weed, W. H., genesis of ore depeowts..

Whale claim.. .. 202 Winchester claim. . eas WV Windfall cation, molybdenite in. 140 ¢ claim. . 7

. group... is

Wollastonite.. oa eae ; 6

Woods, Duncan (owner of elattins), Humming Bird group. . 208

Wookey, S. A... he

218 Geological Survfy, Canada

Y

Paar.

Yale Mining Co.. .. .. .. SE Rhee ee + +14, 26, 162, 186, ibe " diamond drilling Renee iene tueteni es ee "owners of Nickel Plate DUNO Teac soa # Sunnyside mine., .. .. ., ,, Ser tc ay Ke Tplanab mings. ei.) we

Zz

CAPONE CLRID oo. Gh een eee BE Rie KOR e aed Saree Zine (Nee also Sphalerite).. .. .. .

ae

Cm Departmes

How. W. TemPreman Minister R W Brock

a9

Areal Geology

s s

Legend

Hedley chorite

a Gaeaned mane Sediments and tuffs damestones and angillites with inter

bedded black tutte considered to be of Carboniferous age ;

Palaeozoic Mesozoic

Geological boundary

C OSeneeal. Groyrpher and net Dreaghtsman OE Prudhomme, Pranuphteman

Map

Mineral Claims

Near HEDL

Hey: Creek: about 2 male. Scale west of Hadlex Bt Fee 100 0 100 500 eee ee —— Mew 100 o 100 200 A en

Canady artmentt a Mavs

Eqological Survey

Minister APLow, Derury Minister

R WBrocw. Director

imo

3Ritish Columbia

Legend

Culture

Railways

Trails

—

Tunnels

Prospects Water

Rivers and creeks

luternutient streams

Relief'

Coutonrs Showing land torre and elev

ahons above sca tevel Interval 10 feet

MAP 3A AIMS on HENRY CREEK ear HEDLEY B.C. GEOLOGY " Cam" 908 Scale: sts : Feet TOPOGRAPHY nena gaa 25 C.CAMSELL 1908 Metres &. REINECKE 9068 bole) 200 300 400 50. ae i eel

90 FEET TO ! INCH te accompany MemiarNu"

i,

Palaeozoic Post-Carboniferous

Economic Geology

Legend

Silve

eee Geological boundary

C:OSenéecal, Geayrapher and Chief Draught: man OE Prudhomme, Draughtsman. 2

Situation about 8 miles north of Hediey B.C.

g Departr

Geol

Hon W Tewmeman Minit R Ww BRo

GOLDEN ZOx

Near H Sei 100 500 100 0 100

600 Fe

Cau Department of Miws

Geological Survey

cuan Minceten, APlow Deeury Minorca, ® W Baoew Oimeovon

m0

British Columbia

Legend

Culture

Streams

Shjos 2 tsi oe

aert Marshes

Rehef

Map 4A

NV ZON.. MINING CAMP Near HEDLEY B.C

Scale hs Feet 1000 500 2000 a ee — me a ae — Mewes 100 200 300 400 500 a nee ee ee

600 Feey To + Inch

GEOLOGY Subject to revision, C.CAMSELL 1908

TOPOGRAPHY Subject to revision; C.CAMSELL 1908

To accompany Memoir No 2

Microcopy Resolution Test Chart

(ANSI and ISO TEST CHART No. 2)

as Ws

Mes 2 2

1. Mie el

lh

lle

M22 Ws, js.

APPLIED IMAGE Inc 1653 East Main Street

Ca Departines

Geologic

Hon W. TEMPLEMAN, MINiST R.W.Broc

Geology

Wee Hedy . ABERDEEN RIDGE

é LEGEND

: 5 Sedimentary rocks or - ra . ee Std

& i 2 - F

ke Ww Superficial deposits

: aq strain gravel and sands

oO

Ca

Aberdeen formation thin bedded limestones quart utes and argillites, some tutte and

volemuc breccias

Crm

Red Mountain formation tufts and volcanic brecaas with some interbedded quartrites and argilites

Nickel Plate formation lucestones and quartites with thin bands of argillite and tuft

Palaeozoic Carboniferous "

Redtop formation Lmestones quartutes arpliites tufts aud breceias

Igneous rocks

\SteMWINDER MT eee j ra 1650 J Dike aplde. rhyolite and andesite eee "gd"

Granodiorite

Tertiary

lamprophyre and keratophyre

Gabbro porphyritte v. Dlaces and @ marginal facies of diorite

havin,

Mesozoic

d

Dirorite Pr dhorite quarts horde micu deorie a. 37 and porpryrttte dome

Svinbols

Cayrader artinent of Mines

Eological Survey

N, Minister; A.P. Low, Deputy MiNnisTeK: R.W.Brocx Director.

BRITISH COLUMBIA - ea nee San ae ——— T sacheetineenenan! jose 7 ( 'Cup Cu ? / mig & ane ' lf re " . oo ' f ae ae 3 or ; LOOKOUT MOUNTAIN

'. 8 LEGEND Culture gy el Be 'Eme*. ws Lao Roads and buildings Trails Railways Tramways

Electric tramways Bridges

Tunnels

—

Mine tunnels

+

Dams

i e J Mine excavations Water Lf. Rivers and streams

Mesozo!

Cabbre por payritic ing a marginal Hines of

Svinbols

Powait

Foult

ateried but not se

é Fault dowithrow side

/

Fault upthrow side

aa:

Dip and strike

Geological boundary deineated within an error of "50 feet

Geological boundary delineated within an error of [OO feet

Geological boundary assumed

Note: Lnnuanerable dikes and smali uvegular masses of qabbro and dirite are present in various areas but are not shown on the map

C:0.Senéeal. Geographer and Chief' Draughtsman . OE Prudhomme and A.Dickison, Draughtsmen MAP: M/ '

Hedley Minid

British C

Feet 800 ° 1000 Se Metre 90 06 100 200 300 s00

Seale:90 miles to 1 inch

1000 FEET Ti

Map2A

Lining District

Sh Columbia

Seale 3600

Feet 2000 2000 TaN Metres s00 300 600 200 00 900 a

0 Feet To Inch

wwp0

Geology C.Camsell,

TOPOGRAPHY (wubsect to revision

C. Cams Ell, (/N Charge} L.Reinecke,

1907-1908

1907-1908

Ty avcompany Memou

Wv" 2.

Mine tianeds

'

Daas

Sa

Mine excavations

Water

ty

a ri

Rivers and streams

lnteruuttent streams

Relief

Contours showing land forms and elevations ubove seu loved Interval 100 reet

woe

Contours

not well determuned

Heights in teet above sea level

Magnets dedinanon about 25 East

Mesozoic Tertiary

Legend

Seclinentnine poems

aid

Sipertionl deposits

Ca

Crm

Red Mower

z Ws ap

z

a ie

& P

Q Sickel Plate formation fargillite tine tP we

Redtop tirmeaton

Igneous rocks

yd

Cranodionte

d

Hon W Te

Str

Hel

Cera Departurent vf Mines

Geological Survey

Hon W Tempco wan Minister. AP Low Deeury MiniSTER RW Brock. Direcror

British Columbia

'? ; oe ad P 1 df: f d HEL Datum Th00) feet above sea level soc A . v 2 ' 4 ¢ oo L 'Ga . Gad - Gd Datum 1500 feet above sea level QOD ya vay' x ALP Bld hi 7 hat STRECTCRE SECTIONS to accotrpiny Map 2A GEOLOGY HEDLEY MINING DISTRICT B Cc C CAMSELL 1907-1908 Seale : jsdo5 i Feet 6 4 woe 1090 oor woo 7, Metres BH Neg ae to? 200 wo we s00 20 700 00 00 tou

1000 Feet To! Inch

UF Oepartines

Geologic

How W Temeceman, Minis R.W Bro

Topography 1

ASEROEEN Ainge

STEMWINOFR mr

Caprad: artinent vf Mines ECOLOGICAL SURVEY

iN MinisreR AP| RW Brock Diat

Jeputy Minister BRITISH C JLUMBIA

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1OGC LOOKOUT MOUN TaN

Legend

Culture

Roads and brildings

oy, WINDFaL;y

x, PLATE : Trails '

are' as ie % : .

Houlwiayes

NICKER PLAT mr ¥ Tranmiwiays

CLIMAX ' aS

@Lurr Electac tranuwivs

Bridges

38 , SUNNYSIDE wee s a . ,

/ Trine ls

J —

Mine tunnels

+

Dains

Sc

Y Mine extriavations

Water

Ravers and streams

PTipple Tutermuttent streams

oe'

' e? oe, 7 s ' & s me 8 ; ' e HR Dw EK) Y. . x ' : er, Reg" é : . - ' © j , Ble ? ot ' Perea . ' wat TR

a pool] is

on — ry Yam i] ae ¢ f an fond

Sawnmull

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(0. Senccal, Geogripher and Chie Draughtsman OE Pridhomme anu? A Dickison, Draughtsmen MAP LA

coe BON Niemen? 5 Na ke Nd ee See oy HEDLEY MINING D! eo Jy of ne BRITISH COLUME

© be sa : ee

PA : z ( yt "5 4/ Seale : j2d00

ade sas B ee a

oe a ois Mat re no

1000 Feet To 1 Inch

Prasitaw bo

—

Mine thane is

e Dass

Sc

Mitie ear vitiotae Water

. E 2

Ory ie j Kivers andl stream

' lutermiittent streams

a we

Fhimes

" Relief

it eatieags

Contours

inteewnd 100 tet

Contours not wedl determined . ve, ° Heights in feet above sen level

Magneor dectinatnen about 16° Kast bes)

' wn Creek

te pa

La

iG DISTRICT LU MBLA TOPOGRAPHY

subject co revision

1 C. CAMSELL, (iN CHARGE (907-1908 12000 L.REINECKE, 1908

x0 200 soo voo tapa : Nomen —— ) 1 INCH

T accompany Memow N° 2