THE OCCURRH\ICE OF TTN AT THE DtcKsroNE No. 2 oRBODY, NORTHmN IfANTTOBA by 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.