The University of Manitoba

THE OCCURRH\ICE OF TTN AT THE

DtcKsroNE No. 2 oRBODY, NORTHmN IfANTTOBA

Marti:: Gray }4crcice

Trliruli-peg, Manitoba

Iftarcln, l97l+

A Thesis Submitted to the Faculty of Graduate SbudÍes and Research The University of Manitoba

I:i Part,ial Fït]-fillrnent of the Requirements for the Degree of Master of Science ABSIRACT

The Dickstone No. 2 Orebody, a sna1l massive sulphide deposít situated i¡r northern Ïvlanitoba, contain" lirl i¡ amou::ts averaging O"O8/" or 1o6 pounds per ton. ' Most of the tin occurs-as the oxide cassiterite. The cassiterite shows a considerable size range from (.OOI fiÍn. to 0o6 tmno, with approxÍ:nately 99% of a-ll cassiterite present Ín graÍns larger than

Oo1 nm. acrossc_ The larger cassiterite grains e:dribit subhedral crystal

forms, Some of which show the e'ffects of abrasion. Quafr'zt calcite and ' pyrite are most closely associated with the cassiterite u A microprobe study of the'cassiterites shows that the most

connnon trace elem.e=nts are jndium, siJver, neod¡rmium, tur:gsten, iodine and lutetium. Ca1cíum, anti-rnony, and ytterbium occur moderately, whi-le titan-iran, iron, zi:rrc, tantalurn and iridium occur infrequently. Another tin-bearing rnineral was encour:teredo .Llthough not posÍtively identified, this mjneral ís a calcium-titanium silicate,

possibly sphene" l-l_

ACKNOTìILEDGEMH\TS

The uriter would like to thank Dro H. Du Bo lniilson for his help and supervision durirrg the preparation of this thesi-s. Aclcrow-

ledgements are al-so exbended to Mro Ku RamJ-al- whose guidance dwi:rg the

electron rnícroprobe phase of this study proved invaluable. k? RamJ-aJ- also provided the aton-ic absorption data for al-L of the sanpfese The assistance and co-operation of Dickstone Coppel Mines Ïtd"

and Hudson BAy }finjng and $nelting, the present roine operator, are deepþ

appreciated. / Special thanks are due to lh. P. Maï'birr, chief rni:re geologist of Ho B. M. S., who provi-ded the ore sarnples and information without which this sbudy would not have been possible; Dr. Ro Bu Ferguson provided valuable assistance irr the preparatíon

and interpretation of the l-ray powder photographs. Dr.. G. S. CJark of the üniversity of Merritoba and Go Do Pollock of Selco F,:çloration Co. ltd" offered constrrrctive critícísm during the preparation of the marruscript. t-t-l-

TASIE OF COI\TTENTS

CHAPTffi, 1" TI\IIRODUCTTON ...... o...o...occo..oc.o...o.c.e...o.o.c...oo 1

Purpose of the S'budy Iocation and Access ' General Geology History and fuoduction T,aboratory Methods

CHAPTM 2o lìlORtD TIN OCCURRÐICES ..c.e .....cc...... t.....e 7

e CHAPTffi ). MïNmAlrOGï ...... c . . . c . c o ¡ e ¡ ó .'. . ] .. . e o . o . e o ...... o. 10 þrÍte Sphalerite Chalcopyrite r furrhotite Arsenopyrite Quartz Cal-cite Cassiterite

CHAPItrA, 4. PARAGENESIS . o. oc o o ò c c c o o. c...c e . o... c.. o. o oo o.... c...... o. 10

CHAPTm, 5. TIN-BEARING MINERALS AT DTCK.5IONE . c... e.... e e e c. c.. o c o... 27

Sphene Cassiterite Si-ze Di-stribution Spatial Distribution trrfluences on Tirr Concentration Trace Elements

CH.A.HTER 6" SIJM}4ARY AI\ID CONCIUSTONS 39

REFERU\TCES .... tù l-v

],TSI OF TLLUS'RAT]ONS

Figure Pa.ge

lo Location Map 2

2o Sanple Iocati-ons 5 3o þrite Crystals in a .Sphalerite-Quas'bz Matrix l-L 4" furite Cut by Chalcopyrite Veins 11 5. þrite Cut by Vei-ns of Chalcopyri-te, þrrhotÍte and Quat{,z 12 6" ELow Sbrrrcture in a Quartz-Sphalerite-Cha.lcopyrite Vein CuttÍng Through $rrite 12

7o Replacement of a SÞha.lerite Vei-n by Chalcopyrite t3

8. Replacement of Cassiterite by Calcite T4 o Elecþron Scan H:otograph of the Cassiterite Crysbal of Fígure I u l_0. Cassiterite Twjn in a þrite l4atrix t5 l-1. Replacement of a Cassiterite CrysLal by Chalcopyrite t6 f.2. Electron Scan Photograph of the Cassiterite GraÌns of Figure 1J- L6 13" Cassiterite Crystal Cut by Veins of SphalerÍ-te, $rríte, Calcite and Quartz 17 14" Electron Scan Photograph of the Cassiterite Crystal of Figure $ t7 ]-5, Abraded Cassiterite Gra,in Cut by a Chalcopyrite-Quartz Vein 18

]-.6" Electron Scan Hrotograph of the Cassíterite Grain of Figrrre 15 18

l'.l Replacement a Cassíterite Crysbal by Ca-lcíte 19 " of 18" Exsolution l,amell.ae of Chalcopyrite in Sphal-eríte t9 'to L/c Replacement of Sþhalerite by Chalcopyríte 2l 20" Arsenopyrite Crysbals 2J 21,. Replacement of Cassiterite by Ca"lcite .- 23 22" Replacement of a Cassiterite Tvrj4 b¡ Ca1-cÍte 23 23" Cassiterite Grain 24

2t+. J(-ray Powder Photograph: Cassiterite (SUanOarO) 28

25. I-ray Powder Photograph¡ Cassiterite (Sampfe #4e) 28

26. /, z:nc vs % Tin 32

27. % Copper vs % Ttu 33

28. fr z:nc vs % Copper 3h vl_

LTSI OF TABLES

Table Page

1. Size DisbributÍon of CassÍterite Grains 30

2. Atonic Absorption Results 35 3. Trace Element Distribution 36 Chapter 1

TNTRODUCTÏON

Rrlpoge ol the SùFdy The Dickstone Mi¡e of Northern lvlanitoba, a massive sulphide deposit, contains quantitÍes of tjn averaging O.OV" or 1.6 pounds per ton in the No. 2 ore uorru.l The present study was undertaken in order to determine the mode of occurrence of the tin, the spatial di-stributÍon of tin through the nnine, the size distrÍbution of the tin rrineral(s), the trace elements present lrithj:r the tin nineral(s) and the factors influencing the ti¡ concentration.

þcatign_anÈ Agc.es.s The Dj.ckstone MÍ¡e, located in lücrthern Manitoba, is situated at approxirnately norbh latitude 5lroSOt; east longitude 10o036r (¡'igure 1). The deposits are located on the north side of Beaver Tail I¿ke, twenty miles west of Stow l¿ke, l4anítoba" The nrine is accessible by a road which joins the Fl-in Flon - Srow I¿ke railroad west of Snow I¿ke.

General GgoloEv The mine is located w:ithin a Frecanbrian ffAmisk-t¡çett volcanic belt (narned after a t¡pe area west of FIin HLon), exbendÍng from lfektrsko Lake in the east for more than 130 miles due west, past Flin flLon into lPersonal Corønunication: P" ¡4årti-11, Chief Mine Geologist, Hudson Bay Minine and Snelting.

)õ

Saskatchewan. The southeïn limit of this greenstone belt (which averages

30 m:iles in width) j-s covered by Pale ozoic sedimentary rocks r,¡hi-le the northern J-imit i-s bor.rrded by the Kísseynew þeisses which represent highly metamorphosed equivalents of oríginal sedimentary and minpr volcanic rocks (Coates, et aJ., I97o)" \ The sulphide ore body is tabular, varies from 1 to 10 feet wide (averagu: d feet), strikes approximately norbh - south, dips near vertical and plunges ?Oo to the south.f The ore is composed prÍmarily of ¡grrite, sphalerite, chalcopyrite, and pyrrhotite in a granoblastic intergrowbh.

Accessory rninerals are quartz, arsenopyriter âJrd rarely calcite, scapolite and arùrydrite. The sulphides vary from very fine grairred chalcopyrite and sphalerite with ro¡rnded pyrite phenocrysts to coarseli crystallíne bands of sphalerite, pyrite, and chalcopyrite and pyrite. Banding i-s usually encou¡:tered i,uhere there has been some folding of the footwall and Iíkely represents plasti-c flow of the sulphides.2 The intrusive nature of the sulphídes is evídenced by sharp contacts with the enclosing rrcck, inclusions of foliated footwall and hanging wal-f, and the penetration of sulphides j¡rto cracks in the courrtry rock. These jntrusive features may have been caused by remobj-l-ization of the sulphides after emplacemnt.3 \ lPersönal- Coumrw-ication: P" Martjx, Chief Mj¡re Geol-ogi-st, Hudson Bay Mi-nÍng and SneltÍng. 2Pursonal Cormrrnication: Po A. Cai-n, Vice-President, Mining, Sherritt Gordon Mines Ltd" 3rbid, Histpr¡r. .and PrgÈuctig The property, sítuated on 15 claims in the Mcrton l,ake - Herb Lake district of Mani-toba, 1ay idle from 1948 to July, i-l966 when Hudson

Bay Mining and SnqJ-ting acquired a workÍng option. The property was brought into production on Novernber 2, 1970 ïrith H" B" M. S. to receive

75% of the net profits from producti-on. A stríke resul-ted in the r¿ine beíng shut do¡rn on Jarruary 27, lgTl_ after three months of production., Production ï'ras resumed in late Jrrne with the tern:ination of the strike (Fielder, t97I).

The No. 2 zone, containÌng cassiterite, has been m-Ìned at a rate of 350 tons per day sjnce it went irrto production in the fall of lg7}" The ore reserve (No" 2 zone) as of January I,1972, was 2lJrOOO tons grading 2"Otr% Cu and '. .9/o uirnc"l The ore is shipped by rail to ELi¡ Flon where it is treated in the H. B. M. So concentrator and grelter"

, ï,aboratory Eetþods Twenty-four físt-sÍ-ze grab samples were col-lected throughout the mine for use jn the present study (Figure Z), tr: addition to these rrrepresentativert ore sanplesr.two sarnples each of high grade copper

(No. 19, 21) and zinc (No. 20, 22) ore were collectedo These samples were ana-lyzed by aton-ic absorption for copper, zinc, and tj-n, Ten samples were also analyzed for 1ead, but, because of the l-ow óoncentratíons encountered (20 - ?O ppm), these analyses were terrnjnated (Table 2)c lPersonal Con'¡nr:n-icatíon: P. Ao Cain, Vice-President, MinÍng, Sheryj-tt Gordon Mines ]-;td" Þ NORTH < IL

3Ì'

I75 LEVEL

LEVEL

525 aaual.

72,5 LEVEL

925 LEYEL

IIõO LEVEL

DICKSTONE MINE

NO. 2 Z O¡.JE

LONGITUDINAL *qËCTION |"=2Oo

SAMPLE LOCATIO¡{S

Figure 2: Slnfe Tocatioñs 6

A polished section of $ inch dianeter was made from each of the sarrples. These sections were studÍed j-n the }AAC-5 electron ¡nicro- probe at the University of ManÍtoba, Each polished section was scarrned for concentrations of tin with the electron beam of the microprobe. Ï11 addition, as this instrr:nent provides for the sjmuftaneous sca,nning of two elements, scanníng was done for either zinc, sulphur or iron to facilitate the Ídenti-fÍcation of spha-lerite, pyrÍte and pymhotite. lühen a grain wÍth an appreeiable tin count was encor¡ntered, the electron beam could be set on the grain and a chenical arralysis run on that particular mineral. The results were only qualitative si¡rce the microprobe had not yet been sbandardized, and were useful in deterrnining only whÍch elernents vrere present and not their concentratj-ons. Electron photographs of many tl¡r-bearing grains were also obtained from the nícroprobe. The polished sectj-ons hrere al-so studÍed with a reflecting microscope¡ the identifÍcation of cassiterite and of calcite in the gangue were confj::rred by J(-ray powder photograph methods. Chapter 2

T\IORID TIN OCCURRH\ICES

The most impor"bant ti-n n-ineral, both in aþundance and econornic importance, is the oxide, cassiteríte (S:Or). Cassiterite, a member of the tetragonal system, may occur as short prismatic crystals, massive aggregates (radially fibrous botryoidal. crusts or concretionaty masses), bror,,¡n Tounded pebbles with a concretionar¡r structr:re, or finq sand-like graiJì.s (eeruy and Mason, 1959). Cassiterite is arnenable to concentration i-:: placer-type .deposits becauée of its hardness of 6 - 7e specific gravity of 7 t and chem:ical resistanceu tra fact, itt" major producing tin deposits of the world are the placers of Southeast Asia which accotu:t for 60% of the worldrs tin production (sains¡wV, 1969). Alrnopt a1l cassíterite-bearing lode deposits are closely ) ,' associ-ated, both spatially and genetically with granitíc i::trusive rocks (¡iotite or biotite-muscoviJe gra¡:ite) or, as in Bolivia, with shal-Low-seated volcanic rocks such as Quartz latite or dacite' t According to Sainsbwy (1969) t ttMost ofl the major l-ode areas of the world fa']] into one of tuo distÍnct t¡rpes: (f) 1ong, naÍTol,r belts of tjn-bearing grarrites jn a wider j¡rtrusive complex (Southeasb Asia) , or (Z) more diffuse belts of younger gran-ites in exbensive areas of foecarrbrian rocks (Nigería)" Ibst of the rnajor linear befts lie near conti¡rental margins or along major orogenic belts i.:rland j-n which grarr-ite magma was generated.tt Thus, most primary ti.rt deposits are localized along tector¡-Ìc belts in which granite has been intrrrded. I

Econor¿ic tÌn deposits are ur:l

other metalso The Cljmax rn-ine of Colorado produces ti-n frorn its moþb-

denimr ores (Kiileen and Newan, 1965). trr Canada, tfu is recovered, at

the rate of 308 tons per atrrnum, from the lead-zinc-silver-iron ores of

SuIlivan r,ri¡re Southeastern Co}:r¡bia (M¡-LLiSan A966) the of British , " This ore body contaj-ns an average of 0.06% i.i:rr, 90% of which occurs as cassiterite. The cassíterite occurs as sne-l-l ("085 - 0.5 r¡¡n.) weIL- rounded graÌns surrounded by sulfide and/or gangue mjnerals (wfuUigan, ag66)" The tin content Ís highesb along the outer margins of the central thary'entt zone of grrrhotite and pyrite, 'tvhereas the i-nterraediate galena

zone and the outer sphalerite zorLe contai¡r very 1íttle tin ore. Other. ti¡r nd¡rerals present in minor arpunts are the sul:fiáes stannite, francheite,

cyli-ndrite, and teal-lite (Pent1a¡d, 1943).

Tin is al-so preserrb at the lbunt Pleasarrt Mine of New Brrrnswidc, The tin occurs here as cassiterite and sbaruríte in a greisen-type deposit associated with fluorite and base metal sulfide m:inerals near or in altered sil-icic dykes (Petrrit, 176Ð. Other occurrences of ti-n iJr Canada are in the lead-zi¡rc-sifver ores of Galena-Keno Hi1l, ïr:kon Terri-tory¡ and the STowflake Regal Sjl-ver deposit of British Colu¡'bia.

T¡r the Precarnbrj-an Shield, tfu is associated with lithirnn and berylliun nrinerals in muscovite-bearÍng gran-ites and pegmatites and in fracti-onal percentages in massive sulfide deposits jn the }4anitouwadge

area of Ortario, the Noranda and MataganÉ a¡leas of Quebec, the Norrnetal

Mì¡re of Quebec (M¿figanr 1966), and at South Bay arrd Kidd Creek, Ontarío. ,9

At Noranda and }4atagami, copper-bearÍ-ng sulfide deposits are characterized by high, but variable'Co:Ni ratios, hígh tin contents (tÍn-rich pynite), and appreciable amounts of arsen-ic, selenium and silver (Roscoe 2 1965)" ttFbactional percentages of tin fu pyrite, pyrrhotite and chalcopyrite in the deposits at l4an-itouwadge, Ontario and Normetal, Quebec emphasize the possibility of important ti¡ concentration ín sulfide depositsrt

(u*tigan 1966) 2 " A study of the occurrence of tin at South Ba¡r Mìnes, Confeder- ation T,ake, Ontario (eniOge, Jlg72), 'hras done at the University of Manitoba irr conjunction with the present study" Tjrr occurs jn the South Bay massive sulphide zi-nc-coppef orebody in anioi:nts averagÍng O-l3!%. The only tin mi::eral present is cassiterite, wtrich occurs as minute (S - fo microns), wel*L-rounded grains, conr:rnnly s'ubspheroidal ü shape. The amount of cassiteríte is not i-n direct rati-o l^rith the amount of sphalerite although it is with sphalrerite that cassiterite makes its most jrrtimate association.

Ag, La, Yb, and l¡I have a high frequency of occirrrence asr trace constituents of cassiterite while tr:, As, Z::, and Cs occr:r moderately and

Sc, Nb, Cd, Pd, I\h, Ni, Crand Ca occur infrequentfy (griAge, 1972). 10

Chapter 3

MTNTRAÏ,OGY

lyrite Pyrite occurs at Dickstone as subhedral to euhedral óubes and dodecahedrons (Figure 3) and irr massive aggregates" Ifost of the pyrite has been cut by later vejn networks. These veins may be mononrineralic (rigr:re 4) or polymineraHc (Figire 5). Flow structure, evídent i¡r several locations hlithirr these veins (figure ó), 1ike1y represents

plastíc flow of the sulphides rrnder the effects of metamorphism.

The pyrite ranges from fjne to very coarse grained and cormnontry

shows the effects of corrosion by sphalerite and less commonly by chal-

cotr¡rriteo The corrosion may occur along the vein borders which out through the pyrite (figure 7) or along the borders of jndividual pyrite crysbal-s (nieure 8).

A close association between pyrite and the predominant tin- bearÍng nineral-, cassiterite, is evident in many locationso The pyríte may completely enclose the cassiterite (fígure 10) or may just -be adjacent to the cassiterÍte (figrres 10, l-1, 73, :-:5, l-l7).

sphategite, the ,*" oÏffi at Dickstone, occurs pri.:marily

as massive agg:regates (less than 1 nmno to several cne across) which form a matrix for the pyrite crysbals (eigure 3), ¡ut may also occur i¡r veins 11

Figure 3 PYRTTE (py) CRTSI'AIS IN A SPHAIffi,TTE (sptr)- QUARTZ (qtz) MATRTX. POLTSHED SECTÏON X1OO

li.

:t. 4L .

l:', n: .. , .:: i; "'-årr ". ..". : :: :tt &t -* W :. :a : È)"4:t:::a:l::at':l . &..1 .' :,l,.ttll i' {t f. ." ç:

Figure /¡ PYRTTE CUT BY CHAICOPTRfTE (cp) VETNS. POLISHM SECT]ON }CLOO 12

Figure I PYRTTE CUT BY VETNS OF CHAICOPYRIIE, PYRRHOTTTE (po) mn QUARTZ" POLTSHED scTroN n-00

) .f-

Figure ó FLOW SIRUCTURE TN A QUARTZ-SPHALm.TTE- CFIALCOPYRTT]i VET¡] CUIT]NG TTA,OUGH PYRIIE. POLIS]]ED SECTION )C-OO 13

,ajtl 'll..,t I I ,'l.l:iù

Figure 7 REPLACEI,ENT 0F A SPHAI-FA,ITE VETN Bf CHAICOPYRIIE. POLTSIfiD SECTÏON N-OO u

Figure I REPLACEI\4ENT OF CASSITIA,ITE BY CALCIIE (cc). POLTSIJED SECTTON X250

Figure 9 ELECTRON SCAI'J PHOTOGRAPH (tm SCAN) OF THB CASSITM TE CRYSTAL OF FTG.T]RE 8 (noo) 15

Figure 10 CASSffffiITE TWIN IN A PYRTTE MATRTX. POLISI]ED SECTTON N-OO T6

ì\ & ç 4,, a @\ L L t'" t 3 '//tê'

Figure lJ- REPLACEMEÀIT 0F A CASSIIffiIIE (cass) CRYSTAI, BY CHALCOPYRIIE. POLT$IED SECT]ON X2OO

iti:,',,'::|,'

Fígure 12 ELECTRON SCAN PHOTOGRAPH (tr}'I SCnl\T) Op THE CASSTTTN,ÏTE GRA]NS OF FIGURE 11 (lr-oo) T7

"W -:.7,#7{::.t'-' -.7- -r Y *

t ;'¡íffi

Figure lJ CASSITffiITE CRYSI'AL CUT BY VE]NS OF SPHAI.M,IIE, PYRTIE, cAtcrrE, QUARTZ. POLTSHTÐ SECTION X75

Figu.re 1l¡ ELECTRON SC.AN PHOTOGRAPH (ffN SCAN) OF THE CASSTTER,IIE CRYSIAL OF F]GURE 13 (:roo) 18

þ.,,r.r,* EÊ

-ti'r-gure J) ABRADED CASSIIM,TIE GRATN CIJ'I BY A CHAICOPYRIIE-QUARTZ VETN. ROUNDED PYRTIE ]NCLUSTON. POLTSHED SCTION

Figure 1ó }ILECTROIV SCAN PHOIOGRAFII (rrm sc¡N) OF THB CASSIITATIE GR,A.IN OF FIGURE 15. (:r-co) la

.. j ,¡ il .'ì j ''t ,ìl

tu 1,,4&..

'*u %

Figure fi REPLACEIEIüI 0F A CASSItmIfE CRYSTAL BT CAICTTE. POLTSHED SECTTON XzOO

Figure 18 EXSOLUTTON LAI4ELI"AE 0F CHAICOPYRTTE IrtI SPHAI,M,TTE. POLTSHED SECTION ]C-OO 20 which cut the pyrite (figures 6, n" Most of the sphalerite contains exsoluti-on lamellae of chalcopyrite (figure fB) inOicating co-crystallization of these two minerals. Replacement of sphaleri-te by chalcopyrite is illustrated by the encroachment of chal-copyri-te into sphalerite in layers (rigure 19) or along grain boundaries (rigure 7).

Sphalerite contajns trace amor:¡"rts of tin while the other minerafs are essentially devoid of tin.

Ëlatcopvrite Chalcopyrite is the copper ore mi-neral at Dickstone. ït occurs either as massíve aggregates with a considerable sÍze range (less than 1 nun. to several cm. across)¡ fu vein networts (Figures /¡, 5, 61 7) cutting the earl-ier pyrite where it is closely associated with pyrrhotite, or as exsolution blebs or lamel_lae ín sphalerite (Figure 18). Replacement of sphalerite (Figuree 7, a9), pyrite, and cassiterite (figure 11) by chalcopyrite is Índicati-ve of the late genesis of this mi¡reral.

PvcfbotÍÞ $rrrhotite is present in heavily fractured massive aggregates or in vein networks associated wi-th chalcopyri-te (pigure 5 ).

Arsenopyrite Arsenopyrite i-s a minor constituent of the ores at Dickstone.

This rnineral- exhibits good columnar crystals (figure 20) with rhonrbic cIoSS-seGtionS. 2T

.a:...... :.: ,iÞ/.:4.:1

. ,,,,:,1

"t ... al! ,t..tl:tt.11t ,;:Í"'iu.,¡ä,1i.:'ti|:i :

Figure 19 REPLACEME\TT OF SPHALM,IIE BY CHAICOPYRÏTE. POLÏSI{ED SCTION )C-OO

"re%

où"' .tt

Figure 20 ARSmIOPrRIIE (as) CRYSIALS. POLIS]ÌED SECTTON X2OO 22

Quartz

The predomjnant silicate mineral in the Dickstone ore j-s quarLz. tühite and clear varieties were observed ranging Ín size from ( 1 mm. to severaf cm. across. The quartz shows a definite association with cassiterite, often occupyìlg an adjacent positi-on and someti¡nes appearing to have caused corrosion of the cassiterite (Figure 15)" The smaller cassiterite graÍns frequently occur within enrbaylnents along the quartz aggregate boundaries. The quartz, which occurs as irregular aggregates, replaces sphalerite, pyrrhotite, chalcopyrj-te and pyrite.

Cal-cite

The presence of calcite in the ores at Dickstone was confirsned by an X-ray powder photograph of a smal-l area of sample 13c (Figure 21)" The calcite replaces cassiterite at this location. The author was unable to identify the dark mineral which replaces the cassíterite in Figures 8, If and 22.

Cassiteri-te The most important tin mineral in the ores at the Dickstone Mine is cassiterite. The cassiterite occurs as discrete grains, ranging in size from less than 0.001 r,ln. to 0.6 wn. jn d.iameter. The larger cassiterite grains frequently exhíbit a short prismatic and pyraniidal crystal habit (tr'igrrres 8, 10, I!, 73, 17 , 2I, 22) " The crystal faces have been modified by abrasíon (Figure 15) caused during either emplacement or metamorphism and by replacement by calcite (figures 2L, I, :-7, 22) and, chalcopyrite (Figure 11). 23

Figure 21 REPLACEMEI\N OF CASSITM,IIE BY CALC]TE. POITSHED SCTTON T2OO

:'-rfa:.. "::: :.,:.

Figure REPI.ACE}41]üT OF A CASSN'MìITE TWTN BY CALCIIB. POLISIfiD SECTION X75 2l+

Figure 2j CASSTTM,]TE GRA]N. NOTE THE CMCU],AR LTGHT COI,OURED IMFA,ESS]ONS MADE BY THE EI,ECTRON BEAM OF TIfi 1qICROPROBE. POLTSHED SECTTON n-25 +/^É1^

Possible cassiterite twins (Figures 10, 22) were observed in two locations. Except for tiny inclusions of sphalerite, chalcopyri-te, pyrite, quartz and calcite (Figures 8, $ , 17, 22) and the cross-cutting veins of these same rninerals (Figures lJ, 15), the cassiterite grains are homogeneous. Electron beam traverses across several cassíterite graíns (Figure 23) showed that the tin concentration did not vary within individual grains. A more complete description of the tin-beari-ng minerals encoirntered in the Dickstone No. 2 orebody is presented in Chapter J. 26

Chapter 4

PARAGENESTS

The general metamorphic paragenetic sequence at- Dickstone, as ascertained from replacement textural evidence, ís from early pyrite - cassiterite, tô sphalerite - chal-copyri-te, chalcopyrite - pyrrhotite, and l-ater quafrz" Replacement of pyrite by sphalerite, chalcopyrite, pyrrhotite and quarbz indicates an early genesis for the pyrite" Fhrthermore, the

pyri-te is cut by exbensive vejn networks of these same minerah (¡'igures {, 5, ó). Texbural evj-dence was not observed v'¡Ïrich could enable the author to ascerbain the relationshíp between pyrite and cassiteriteo l

The cassiterite is replaced by calcite (¡'igr:re 21) and cha^lcopyrite (Figr:re 11)¡ suggestÍng an early formation for the cassiterite.

The replacement of pyrite by sphaleri-te, chalcopyrite, and pyrrhotite suggesbs a late formation of these rni¡rerals. Exsolution lamel-l-ae of chalcopyrite in sphalerite (nigure 18) suggests co-crystallization of these two mi¡rerals. Replacement of sphalerite by chalcopyrite (figrrres 7, AÐ indícates that some chalcopyrite formed later than sphalerite. þr,rhotit,e, which also'replaces sphalerite, appears to have

co-crysta.-l 1 ized r,,rith chalcopyrite.

Quarbz and calcíte have formed late i¡ the Dickstone oreso The qtafrz replaces sphalerite, chalcopyrite, pyrrhotite and pyrÍte while the calcite replaces cassiterite. 27

Chapter I

TTN-BEAR]NG M]NMAIS AT DICKSTONE

Concentrations of tin were encorrntered in two mi:rerals at the Dickstone Mi-ne through the use of the efectron microprobe. The more cornmon of these tr,'¡o was i-denti-fied as cassiterite with the aid of X-ray powder photographs (figure s 2h, 25). The other tjn-bearjng m:ineral is a calcium-titan-ium silicate, possibly spheneo

Sphqne

The tin-bearÍng nrineral denoted as sphène was not posi-tively identi-fied. Lack of starrdardi-zation of the microprobe prevented a quantitative chen-ical analysis, however, a quaiìtative analysis indicated that this rnineral is a calcium-titanium silicate,

Sphene, wÍth the chenrical formrla CaTiSiO5r cornmonly occurs as an accessory mÍneraf irr i¡rterrnediate and acid igneous rocks and i¡ metamorphic ncckso

At Dickstone, sphene occurs as sna]l (o.oo6 - O,OJ- rrn.), rr¡rrnded to sub-rounded, elongate grains" These grains are brown and are most commonly associated with qrLarX,zo A. total- of approximately 10 - 15 grains was encormtered in two políshed'sections. The tin corrnt, although not nearly as high as jn the cassíterite,

is several times higher than the backgror-:r-rd value, indicatjng a Èlight

concentration of tin in this nineral-. The similarity between the Sn4* and ti4* ionic radii- (s.4+: oo?LAo, Ti4+ = 0"68A0) and octahedral ¿ó

Figure 2l¡ X-RAY P0hlDm, PHOTOGRAPH: CASSTImTTE CU/NI RADIATION. 57.5t+ W¡" DTIMEIm CAMm,A. SIANDARD (UUrVmSrrT OF MANIIOBA)

Figure 25 X-RAY POWDffi, PHOTOGRAPH: CASSIIM,IIE CU/NI RADïATïON. 57.54 pn¿. D]AMÐIM, CAI,M,A. SAMPIE FROM DTCKSTONE NO. 2 ORBBODY (mO. 4u) 29 coval.ent radij- (s"it : I.L+5 t Tiív : \36É; Cotton and lrlilkin son, !962), accounts for the abi-lity of tin to substitute for titaniu:n in sphene. The trace efement content is sim:ilar to that of cassiterite except for the presence of rubidirr't (Rb) and manganese (m:) in the sphene and the absence of silver (¡e) and neodyn,-ium (uC) in one sphene sample (taute 3),

CasëLteËiIe

Si-ze Distribution:

Cassiterite occurs at Dickstone as discrete anhedraJ- to subhedral grairs. The grains range in síze from less than 0.001 nrn. to about 0,6 mmo as measured along the longest dimensíon of the grai¡. The cassiterite is brornm and is distinguished by its characteristic internal- reflectíon.

Table I shows that atthough many smal-J- grains occur, 99.8% of the cassiterite is in grains ranging from 0.1 to 0.7 mm. i¡r longest dimension.

Spatial Distribution:

An attempt was made to contour tin values on a longitudinal sectÍon of the Dicksbone No" 2 Orebody. The random occurrence of tin throughout the r¿ine made thi-s effort Ímpractical. . It is concluded that the ti¡ has not concentrated jn any recognizable pattern jn the orebody dowr to the ILlOt levelo Perhaps more deta-11ed sampling would reveal concentration patterns but that is beyond the scope of the present papero 30

Table 1 STZE DTSIRIBUTTON OF CASSilffi'ITE GRAÏNS Size Rang"-;r(mm. ) Sanple No. of t Ng. Cassiterite E17 Gra-Ìns .001_ "001-.01 ooI-uf "!-"5

1c h 0 0 3 I 0

2c ) 0 0 U 3 0

c) 0 3c 7 0 6 1

l+e I 0 1 0 l_

0 hw 9 0 1 2 6 0 5c 4 0 2 1 1

6c 2 0 1 0 1 0

0 7e ö 0 7 0 1 0 7w 2 0 0 2 0

8c 3 0 0 3 0 0

13c 7 0 0 1 Lt, 2

r<À 6 o 2 o 1

Total 6Z 5 20 t5 18 l+

Fbequency of Occumence (%) 8.1 32.3 á4oá 29.O 6;L+ 100.0

Apnrirximate Volume +

Tota.l Volrrne -q tþ3ÞIO-A " I ;ár-x(¡¡'¡. )3 5xlO' 3"2hx,]:o' "496 "g6h Distríbution of Cassiterit" (%) trace trace o.2 35.9 63"9 100.0

As measured across the longest dimension of the grai-n

Calculated by cubíng the mean of the Síze Range Equat to Approximate Volume x.the number of grains ín that size range 3L' trafluences on Tirl Concentration:

The relationship between zinc and tin is èhovm in FÍgure 2ó" The data points show a brrcad scatter except at the two highesb zinc concentrations where tin contents r'rere correspondixgly high. A broad scatter of data points is al-so j-ndicated between copper and tj-n irr Fígure 2?" Ïr addition, Fi-gi:re 28 índicates that no correlation exists between zinc and copper concentrations. SiJrlllarly, fog - log and semi- 1og plots of the data faiJ-ed to indicate any relationship between these three elements.

The data for Fígrrres 26, 27 arñ 28 was obtained from Table 2"

Trace El-ements:

A total of twenty-six trace elements was detected in the cassiterite of the Díckstone Mine, through the use of the rnicroprobe analyzero These elements were documented on.1y qualitatively so their concentrations are not laroun. Table J shows the frequency of occurrence of each trace elemento

The most abundarrt trace el-ements on a frequency of occurrence basis, are i¡dium (h)r siJver (¿s), neodym:iun (Nd)r tungsben (ÏI), lutetium (Lu), and iodine (r). Calcium (ca), antÍmony (sn), ano ytterbi-un (fb) occur moderately, whÍJ-e titæriun (ti), i-,z..on (¡'e), zi:rtc

(tn)¡ tanta.l-um (Ta), and iridium (fr) occur idrequently. Gerrnanium, galliun, erbium, 1ead, brnrníne, copper, radium, vanadiun, sulphur, osn-lum, lanthanum, and bari-r¡m are present in only rn-irr-imal amor:¡rts"

The fourteen most colnmon of these trace el-ements have aIL been described ín the literati:re as constituents of cassiterj-te except for

Nd, Lu, I, fr, and ïr. The often documented trace elements niobium, 32

o u z. o N o ñ co !o Oo o oR *eooo

%TI N

Figure 26: % Zinc vs % f:n 33

oo o

æ. HB ()o bq. 6 O9 o ooæ o oo o o O.ìoo o o"o o.l o:2. % TtN

Figure 2J: /" Copper vs % Ti.:n 3L

30 o z.J25 ñ N2 u o o I o o o ro oo d o. oo o o Ã

6 t4 % COPPER

Figure 28: % zi:nc vs % Copper ))

Table 2

AT0ImC ABSORPTTON RESUTTS

Sample No. % l:-n % zinc % Copper ppm ï.ead

22 o.257 29.g 5.20 20 0.187 41.8 0.09 3c o.764 14.8 2'9o 6c o.I24 2r.9 2.45 L*e 0.l-l_6 9.1 o.64 15c 0.106 14.0 l+.50 a' 2T 0.104 10.6 13.0 5c o.Qgz 19.9 1'90 40 rO O 7J+c 0.088 ,/a,/ 4.62 lOhI 0.083 23.7 3.80 _?2_ l'5e o.o73 l.6.7 3.O5 LLc o.o72 10.5 4.80 Hw o.o72 11.0 13.9 18c 0.061 u,l+ r.54 2c 0.060 15.6 8.0 -a: 6w 0.058 10.1 7.9o 7c 0.058 r7.2 o.53 30 4w o.o54 o.3 2.95 g.l_ L2c o.o53 4.31+ ;õ l-6e 0.051 10.8 0.90 9e 0.050 lf.7 2.30 6o T9 0.049 42.7 13.9 -;, a3c 0.044 oo l+.39 1c 0.034 u.o o.32 Bc o.o29 12.8 f .05 70 7e o.026 Ão 3.7o .;, 13e 0.021_ ]'5.9 3.06 % 0.012 26.6 o.53 Table J TtuCE ET,'rllvlFlw DISIRBUTION

SarnFle I 11 Ag Nd W Lu Ca I Ti Fe S13 Zn Ta Yb Ir Rb Ifi1 3.¡ Cassiterite

1c V x J.

2c-I JI JT r r JL

)a-9 .X ^ x Jt À i" x

3c-2 å x {L x X å r JI å X x

h,e-2 J! å X X X X Å

lú,r JL {\v Y X v 6c JL ¿! Y J\ J\ x Y x JI JI Fbequency of Occurrence 100 l_00 100 86 77 l+3 57 2Q ta 9A )a (%) u 43 u 0 0 -:-- b. Sþhene Y ]r 5c-:-- x J! JI Y JI ï J! Jt JT

9w T v ]¡ J! å X Fbequency of 0ccurrence ..-...-- (%) 100 5o 100 5o' 100 0 100 100 0 'U 5o 50 0 0 100 50 \, o\ 37

scandiun and cadnrium are notably absent in the Díckstone cassiterites" Nd, Lu, and Yb all belong to the lanthanide or rare earth

elements hrith Nd being, by far, the most abr:ndant of the three. Nd

and Lu show a high frequency of oceurrence at Díckstone while Yb occurs moderately (fa¡te 3)" The author does not lmow of arry other occurrence of these rare earth element" i ."""iterite. The :¡are earth el-ements show a wide distributi-on j-n nature i,rrith higher concentrations occrrri-ng

irr some acid igneous rockso lb is present jn fl-uorj-te and hydrornicas at

l4orrnt Hleasant, in amounts rangi-ng from O.OOI% to O"OI% (Petruk, l96t+),

suggesbing an affjni-ty for some Ca *1ns¡s]s (CotOsctrnid+,, 1954)" Tungsten, whi-ch shows a high frequency of occnrrence at

Dickstone, occurs elsewhere in cassiterite in amounts ranging from O,I%

Lo a"o% (Petruk, l96h; Novák et aJ.. , L962). Tungsten is a weIL documented trace element constituent of cassi-terite where ít nay substitute for tjn (Greaves et aI. , l?7l-; HoskÍng, 1963; Petruk, I96t+; Sainsbury, I96Ðc ,\ T::dium has a high frequency of occurrence i¡ the cassiterite at Di-ckstone. Ivanov and l,i-zunov (1960) found that indium concentrates i-n minor amounts (O.OOt% - O"OI%) in cassiterj-te-sulphide deposits, especially those with exbensive development of sulphide stages of mineralization, high temperature paragenesis of early mineral- associations¡. and complex composition of the ore. They al-so found that i.ndium ís widely distributed in various types of Pb - Zn deposits enriched in tin, as at Su11ivan, and that the concentration of indium j-s dírectly proportíonaf to the tin concentration. They concluded that the chemistry of the ore solutions is important in controllÍng the concentration of i¡rdíum" Deposits with a fow concentrati-on of indium have a Iow sulphide con- 3e centration or an absence of, or a low concentration of, tin" Títanium has a very sÍmilar geochernistry to tin. With similar ionic radii these elements are irterchangeable and, in fact, rutile (rior) is isomorphous with cassiterite (snor)" Novák et al" , (t962¡, in their study of the KutnfHora ore deposít found that the cassiterite contains Ti in amounts rangÍng fyom I% to IOft| Ca, Fe, pb and W, O.I%

Lo l"O%; AS and Cu, O"OI/" lo O.aft-, and Ga, S, V, and Zn in amounts less' Lhart O.OA%. Sinrilar results were obtained by petruk (]]g6h) for the

Mount Pleasant deposit although titani-um Ì,ras present in lesser amoqnts (o"t% - Uo%) i¡r the cassiterite" 39

Chapter 6

SUMMARY AND CONCLUSTONS

lvith the exception of trace amounts of .S'r in sphene, cassiterite ís the only tin nrineral- forrnd in the Di-ckstone No. 2 orebody" Cassiterite occurs as discrete grains, ranging in size from less than O"OOI- mm. to approximately 0"6 rnm. jn dj-ameter. Subhedra.l crystals greater than 0.1 mmo in dia:neter accoru:t for approximafell 99% of Lhe cassiterite" The trace element content of the cassiterite is simil-ar to that which has been docurnented in the literature. trrdium, silver, neodym.ium, tungsten, lutetium and iodine occur most frequently in the cassj-terite at Dickstone" Calcium, antimony and ybterbi-um occur less frequently, whi-Ie títanium, íron, z):rtc, tantaJ-um a¡d íridiun occur infrequently,

One other tin-bearj¡rg mineral was encor¡ntered, although only in mi-nor arnountso Thi-s mineral was not positively i-denti-fi-ed, although qualitative nricroprobe data has shovm it to be a calcium-titanÍum silj-cate, possibly spheneo

A direct relationship between concentrations of tjn and either copper or zine could not be ascertaj¡ed for the Dickstone No. 2 orebody.

The'ores at Dickstone contain tin in ìrmounts which average o"o8% to 1.6 pounds per ton" 99"8% of the principle tin rnineral, cassi-- terite, ranges j-n size from 0.1 mmu to 0.6 mmo A comparison with the Sull-ivan Mine, where cassiterite is profitably exbracted as a by-product from the Ph-zn-Ag ores, shows that this mine contains 0"06% Lí:n, 90% of 4o

which occurs as cassiterite grains ranging in síze from 0.085 - 0.5 Í¡n. Assum:ing i,}ha| >9O% of the tin at Dickstone occurs as cassiterite, the author believes that aLL other thÍngs being equal the cassiterite could be profitably exbracted from the Dickstone ores.

The employment of a Denver Buclcnan Tilting Concentrator, as at Su11ivan, should ensure effective recovery (>ZO%) of the extremely fine cassiterite (Denver Equipnrent Co., !962). The recovered cassiterite would be so1d, as Cominco does with the Sìr1livan cassiterite, as tin concentrate to a United States smelter.

The Dickstone ores contain 1.6 poi:::ds of Sn per ton or 2.Oh

pounds of SnO, per ton. AJ-lowíng 10ø dilutÍon and 70% recovery by

tabling, and assurning 95% of the tin occurs as cassi-terite, it would be possible to recover L.22 porrnds SnO, per ton.

An approximate price of $O.fB per poirnd of tin ore concentrate was obtained from the Canadian Mines Handbook (l.glO-ll) by dividing the value of tin ore exports by the quantity of tin ores enported and averaging over the two year peri-od 1969-70. Applying this price to the Dickstone concentrate, it is found that the Dickstone ore is worth $0.95 per ton i-n tin concentrate" The smal-I size of the Dickstone No" 2 orebody coupled with the fact that the Dickstone ore is mixed with ore from other mi.:aes before it is milled at Flin Flon, however, would discourage any atternpts at the exbraction of the cassiterite from the ore. 4r

REFMENCES

Berry, L. G. and Mason, B. (lgSg): IEneÊaloEy, lü. H. Ibeeman and Co., San trbancisco Bridge, D. A. (]g7z), The Geology and Geochemistry of CassÍterite as a Minor Constituent of the Zinc-Copper Sìrlphide Deposit at South Bay MÌnes, Confederation lake, Ontario (University of l4anitoba, rrnpublished tr4Sc thesis)

Coats, C., Clark, L., Buchan, R. and. Brummer, J. (fgZO): Geology of the Copper-Zinc Deposits of Stall Ï¿ke Mines Ltd., Snow l¿ke Area, N. l¡Ianitoba, Egg&-lggt VoI. 6lr pF. 970-984 Cotton, F. A. and Wilkjnson, G. (tç62), 'ürJiley Advanced -IfrorEanic themlstÊv, John and Sons, Iþw York Denver Equipnrent Co. (tg6Z)¿ Denver, Colorado, lst

Fielder, Fo M. Éditor (rç7r): Canadian tr4nes Handbook, Northern Miner Press T,td., Toronto Goldschm:idt, V. M. (]:gSl¡), Ge_ochemi_gUly, Oxford University Press

Greaves, G., Sbevenson, B. G. and Taylor, R. G. (fç?f)t l4agnetic Cassiterites from Herberton, North Queensland, Australia, .Econ.-!g.gL, Vo1. 66, pp. 480-487 Hosking, K. F. G. (tg6l): Geolory, Mineralogy and Paragenesís of the Mount Pleasant Tin Deposits, Can. Mirr. Journal, Vo1. 84, pp. 95-102 Ivanov, V. V. and Ï,i-zunov, N. V. (fç60): 0n CeitaÍn Peculiari-ties of the Distribution of Tndium in E:dogenetic Ore Deposits, Ge_ochemistr:¿, No. 1, pp. 53-66

Ki11een, P. L. and Newan, i/ì1. L. Ogef)z Tin in the United Sbates, U. S. Ggot- SuËg. Report MuIligan, R. (tgCO): Geology of Canadian Tin Occurrences, @, Paper 64-65 1,,2

Novák, F., Blum1, A. and Tac1, A. (tg6z): The OrigÍn of Sbaruaite by Replacement of Cassiterj-te jn the Turkank Zone of the Kutná Hora Ore Deposit, Min. MaA., VoJ. 33, pp. 339-31,3 Pentland, A. G. (tgt+S)z Occurrence of Tin in the Sul-li-van Mine, Treng. Can. trrgÞ. Miq. Uet., Vol" lÍ,VK, pp. 17-22 Petruk, W. (A96ù: Mineralogy of the Mount Pl-eaeant Tin Deposit in New Brunswick, Can. Dept. Mines and-IecL. Suryeys, Mines Br. Tech. 8u11. TB-56 Roscoe, S, M. (tg6f): Geochenical and Tsotopic Sbudíes, Noranda and l{atagarni Areas, CIMM Br!-l-., Vo1. 58: pp. 965-97I Sainsbury, e,. L. (tg6g)z Tin Resources of the hlorld, U. S. Geo]._Srrrv., BuLL. 1101