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Canadian Mineralogist. Vol.23, pp. ... canada centre for Mineral and Energt Technologt, 555 Booth Strcet, ottawa, ontario KIA oGI ... demonstrate the credibility of the data obtained and ...... ing Sn recovery since one cannot ascribe all the Sn.
THE CANADIAN MINERALOGIST Journal of the MineralogicalAssociation of Ganada

Part 2

MAY 1985

Volume 23

Canadian Mineralogist (198s) Vol.23, pp. 133-148

ANALYSIS OF TRACE ELEMENTSIN SULFIDES PROTON.MICROPROBE DEPOSITS FROM SOME MASSIVE-SULFIDE LOUIS J. CABRI canadacentrefor Mineral and Energt Technologt,555Booth Strcet,ottawa, ontario KIA oGI JOHN L. CAMPBELL ' Departmentof Physics,Universityof Guelph,Guelph'Ontario NIG 2W1 J.H. GILLES LAFLAMME CanadaCentrefor Mineral and EnergyTechnolog!,555Booth Street,Ottawa,OntarioKIA OGI ROBERT G. LEIGH AND JOHN A. MAXWELL Departmentof Physics,Universityof Guelph,Ontario NIG 2W1J. DOUGLAS SCOTT Kidd CreekMinesLimited, P.O. Box 175,Suite 5000,CommerceCourt, Toronto, OntarioMsL IE7 So[,tMnIne

ABSTRACT We havedeterminedthe amount of Ge, As, Se,Ag, Cd, In, Sn and Sb present in solid solution in m6jor sulfides suchasbornite, chalcopyrite, galena,plrite, pyrrhotite and sphaleritefrom three massive-sulfidedeposits(Kidd Creek, Geco and Mattagarni-Norita) and one carbonate-hosted Pb-Zn-Ag deposit (Nanisivik). The analyses were performed mainly by proton microprobe (down to levels of - 7 to 20 ppm) and were corroborated, for concenfiations above - 200-300 ppm, bY electron microprobe. Silver, selenium and indium concentrations in sulfides from the Kidd Creek depositvary with ore type. In general,galena and chalcopyrite are important Ag carriers, but sphalerite is of secondaryimportance. Occasionally, pyrrhotite and pyrite havealso beenidentified asAg carriers, but an evaluation of their significance requires further work. Tin is an important trace constituentin much of the Kidd Creek chalcopyrite, as is arsenicin much of the pyrite. More accurate material-balancesmay be obtained in future for elements such as silver by combining tlre results of in situ traceelement analysis of all major minerals with quantitative mineralogy.

On a determindla teneuren Ge, As, Se,Ag, Cd, In, Sn et Sb sousforme de solution solide dans les principaux sulfures, tels bornite, chalcopyrire, galbne' pyrite,tpyrrhotine et sphalerite, provenant de trois gisementsi sulfure massif Kidd Creek, Geco, Mattagami-Norita) et d'un gisement Pb-Zn-Ag (Nanisivik), i roche-mErecarbonatde.Lc analysesont 6t6 effectu6esprincipalemetrt par microsonde protonique (seuil minimum - 7 A 20 ppm); celles qui accusaient une concentration sup6rieurei - 200-300 ppm ont 6t6 corrobor€esd la microsondedlectronique.La concentration en argent, sdl6nium ou indium dans les sulfures du gisementde Kidd Creek varie selon le type de minerai. La galbne et la chalcopyrite sont g6ndralement porteurs d'argent importants, tandis que la sphal€riteest d'importance secondaire.Pyrrhotine et pyrite aussiont parfois 6t6 identifi€es comme porteurs d'argent, mais leur dvaluation n6cessiteraune 6tude plus approfondie. A Kidd Creek, l'6tain est un constituant-trace important de la chalcopy' rite, commel'est I'arsenicde la pyrite. Desbilans plus pr€cis des mat6riaux pourraient 6tre obtenus en combinant iLla mindralogiequantitative l'analysein situ ds 6lEments-traces dans les principaux min€raux.

Keywords: trace elements,proton microprobe, MicroPD(E, electronmicroprobe, base-metalsulfides,Ge, As, Se,Ag, Cd, In, Sn, Sb, Kidd Creek,Geco,MattagamiNorita, Nanisivik.

Mots-cl^s: 6l6ments-trace,microsondeprotonique, MicroPD(E, microsonde6lectronique,sulfures desm6taux de base,Ge, As, Se,Ag, Cd, In, Sn, Sb,Kidd Creek,Geco, Mattagami-Norita, Nanisivik.

133

t34

THE CANADIAN MINERALOGIST

INTRoDUCTIoN The proton microprobe (Micro-PIXE technique) was used to determine quantities of trace elements in major sulfide mineralsfrom someCanadiansilverbearingZn-Pb-(Cu) sulfide ores.The work reported here is a follow-up of the encouragingearlier results (Cabri et al. 1984a,b, Harris et al. 1984)with this analytical technique, which is considered a method complementary to already established methods of quantitative mineralogical investigation. The major objectivesof this investigationare (a) to demonstratethe credibility of the data obtained and (b) to illustrate the usefulnessof such data in quantitative mineralogy and mass-balancecalculationsinvolving minor elementsin massive-sulfidedeposits currently in production. All but one sample analyzedcame from massive base-metalsulfide ores,mostly from the Kidd Creek mine, Timmins, Ontario (Walker& Mann ard 1974). Whereasthe major emphasisof this study concerns the identification of the silver carriers, it is also of practical importance to know more preciselythe partitioning of seleniumbecauseof the deleteriouseffect of high concentrationsof seleniumin copper concentrates. SAMPLES

samplesand five drill-core samples,were studied. The samplesare consideredto form a completesuite representativeof run-of-mine typesof ore collected in January, 1983,with mill headsuniformly about 250 ppm Ag for "C" ore and 30 ppm for "A" ore; however,most of the samplesare not preciselylocatedin the mine as they were taken from the rodmill feed belts. Figure I showsthe location of the five diamonddrill-core samplesand the geologyin the vicinity of the bornite zone on the 20@ level. The samplesare classifiedeither as Zn-Pb-Ag-(Cu) "C" ore (massive,bandedand brecciaores,North orebody),Cu(Zn) "A" ore (stringers,both North and South orebodies),bornile zone(South orebody,Thorpe et al. 1976,Pringle & Thorpe 1980)or bornite-zonehalo (mainly massivechalcopyrite).This classification, together with mineralogical descriptions,is followed in Table l. Mottagami-Norita A + 100-mesh fraction of zinc concentrate (14/03/ZnC) from the Mattagami and Norita mines of Mines Noranda Lt6e, near Matagami, Quebec (MacGeehanet al. l98l) was examined mineralogically. Sphaleriteand chalcopyritegrainswereselected for analysis;no silver minerals were found. Geco

Kidd Creek mine Thirty samples, consisting of twenty-five hand

A head sample (-4 mesh) from Noranda's Geco

'/ / / / / , / , . '/ '/ ,/ /"/ r/ sfringer cholcopy?lt€in chlorllic rhyolite

\\

2028X-C

2OOOlcvel

o- 2 0 . l o @ 8 0 t @

Soulh orebody Kidd Crcck mi]l Tlmmins,Onlorlo

leef

g

mcfrc8

\

\\\

\\\

\

\\

Ftc. l. Plan view of 20@ level, south orebody, Kidd creek mine, showing samplelocations.

135

PROTON-MICROPROBE ANALYSIS OF TRACE ELEMENTS IN SULFIDES TABLE

Mineral-oqy:

Number nC" ore

(massive,

1.

RIDD

CREEK MINE

SAMPLES

banaled anal breqcla

ores) gn>asp.

Massive

83-2

Masslve

fine-grained

sp with

py bands.

Sp, py>G>>cp, po>>asp, gn. po anal py.

83-3

l,lassive flne-grained antl trace cp.

sp with

py breccia

py>G>cp, po>asp. Sp, Ag in po, py and G.

83-4

t{assive sp wlth pyrite bleccia.

83-5

Bandeal fine-grained sp and py sith coarse gn in the 9p.

83-7

coarse-glained sP.

83-9

cranuLar

83-10

Fine-gralned sp.

83-Ll

pyri!e breccia masaes with I'ine-grained recrystallized borders of cublc crystals and nlnor gn ln chelty rhyol-ite rith disseninated sp.

Py, c>>gn,

83-13

E'ine-grained pyrlte stltlal sphalerite

Py>sp, G' cp>gn, and cp.

83-14

Coarse-gralned py interstitial sp.

83-l-5

Massive intermediate-grained thln quartz veins.

83-18

I'fne-grained around graln nino! sp.

83-19

Alternately bandedl (5m) fine-grained py and cp rith nlno! ap ln py bands.

Cp>py>c>>sp>po, cas.

83-22

Partly sp cu!

Cp>>py>c, cp.

83-24

Gn veLn in sp and py.

83-25

Massive gn.

nAn ore

trace

Sp>>G>py>cp>casr po, rn po.

83-l

coarae

sp with

nicroscopic

Mineralogy:

macrosqoplc

coarsely

cp and

mino!

pyrlte

wlth

Ag found

in

sp,

and

ln py and G, areas

Py, sp>>G>9n>>po, cas>asp. tt>my?>>dy? in gn.

Large

Py>sp>G>>qn>>cp>cas, asp.

Trace !t

Py>>sp>>G, gn'

bteccia with inlerand trace cp and gn. with

minor

py!j.te

with

pyrlte breccia invaded boundarj.es by cp and

hi-Ag

of

in gn and

po,

Py>>sp>>G, 9nr

cp>po'

asp.

asp.

cas,

Trace Ag in po,

po.

py

cp.

py>>sp>c>gn>caB.

Cp>py>>po, c>sp.

tarnished cp with trace bn and py bands. by fine-grained coarseLy-banded

found

P y , G > > s p > > c p ,g n , p o .

dlssenlnated

breccla

Traqe Ag founal in

py.

nchertn.

in

Trace Ag found

Trace t!

Sp, py>G>>>cp, gn, asP. and trace t! in sp.

cryslalline

gn and py with

pyrite

9n.

fine-.graineal

sp,

Py>sp>>gn, c, found ln gn.

Trace

cas. po,

Trace A9 in po. A9 found

cas>asp.

cn>>py>ep>po>c, cp>asp.

in

py and

Trace Ag-lich

Ag-rich

tt>aly found

tt>dy in

(stringers) py nrosettesn

py>>c>cp, gn>asp.

83-6

I'ine-grained 1@.

83-8

Coarse-grained Erace sp.

83-12

py bleccla Coarse-grained gn. intergranular

83-l-6

py nrosettesn Coarse-gralned to L cm with cp veinlets in fl.ne-grained black (283L0 stope, near bolnite natrix zone).

py>>c>cp>po>asp.

83-1?

granuLar py with Coarsely-dlssemlnated cp stringers ln ctrlorltic rhyolite.

py>>c, cp,

83-21

Fine-grained

Cp>>G>po, py, ln the cp.

83-23

Masslve coarse-grained cp with euhedral aLbite clystaLs to 8 M (L622 L stope).

sp wlth shiny

to

rrcleavabLert py wi.th

banded cp in

with

dark

trace

rhyolite.

Fy>c>>sp>cp>cas,

Trace Ag in py. aep,

po.

py>>c>>gn, sp>po, cp.

Cp>))py,

sp.

c>cbt,

qas.

cas,

Trace etn monazite?

flnely

disseBinated

r36

THE CANADIAN MINERALOGIST

TABLE I Continued zone halo

Bornite 83-20

a3-26

Massive cp margj.nal

S3-27

adjacen! Massive cp lmedliately zonei DDn 2295 Q LO7t.

83-30

st!inger cp ln rhyolite DDH 2299 Q 66.5,.

e r00.s'.

Bornite

t o bn zonei

Trace tt

cp>>c>>stn, asp, sp.

s!rinqer sp. 163!. M

cp-ln-rhyolite coarse-graineal ore wlth trace dlgsenlnated siope, nea! bn zone.

DDH 2295

C p > > G > s p > n k ?P, Y .

!o bn

c p > > G > s c n / k e s ,g P > P Y .

in G.

G>>cp>py.

near bn zone;

zone qp in bn z o n e i D D H 2 2 9 5 @ 1 1 3 ' .

83-28

Strlnger

83-29

Massive cp in bn zone with 2299 Q 54t.

!!ace

Cp>>G>>bn>naw, stndt

py>crl,

Cp>>bn, c>di>col>tn.

bniDDH

and trace

Trace en, crL,

nn. boh, cv,

eu'

boh bornite, asp arsenopy!ite' siLver, Ag natlve Abbreviati.ons used3 ac acanthj.te, .bn colusile, col chalcopy!ite, cp clausthalite, clu cbt codal!ite, bohdanoriczite, cas cassigerite, G gangue' eu eucalrite, enargite' en dyscrasi!e, dl dlgenite, dy cv covetll.te, cr1 calrollite, po naumannite' my miargyri_t-e., nn ni mackinawi!e1 miw mawionite, kesterite, 9n gaLena, kes tn tennantite, stannoidite, stnd py!ite, py s!n stannite, sp sphalerite, iyrr-nofite, tt tetrahedrite

mine in the Manitouwadgemining camp, Thunder Bay mining district of northwesternOntario @riesen et al. 1982)wasprepard for analysisof chalcopyrite, sphalerite, pyrrhotite and pyrite; no silver minerals were observed. Nanisivik Sphal6ritegrains from a hand sampleof ore from the Nanisivik zinc-lead deposit, near the northern tip of Baffin Island, N.W.T. (Clayton & Thorpe 1982,Olson 1984),wereanalyzedbecause$phalerite is known to be a silver carrier in that deposit(McIntyre et al. 1984).

TABLE

2a.

X-RAY LINES

AqLq

(PbrAg) S

Galena Spttalerite

&etaL

SeKo

Polishedsections(3 cm in diameter)wereprepared for all the samples and carefully examined microscopically. Grains of chalcopyrite, galena, pyrite, pyrrhotite and sphalerite,free ofinclusions; wereselectedand sawedfrom the sectionsas2-4 mm cubes.Theseessentiallymonomineraliccubeswere resetin araldite, together with appropriate synthetic standards(Table 2), to make new 2.5-cm-diameter polished sectionsso that all suitable grains of a selectedsulfide were located in one section. The new sectionswere, onceagain, carefully re-examinedwith

line ZoKo

(zn,Ee)s

n te

Ore microscopy

FeKc

CdLa

InLc

(zn,Fe)s

cds

(znrAgrIn)s

C u 4( F e r Z n )5 5 g -

SnLq

Fe (S,Se)

.(znrAgrIn)S

Pyrite Chalcopyri

Sbtq

TECHNTeUES

AND STANDARDS USED E.OR ELECTRON-MICROPROBE ANALYSES X-ray

MINERAL

ANelvrrcel

c u 4 F e 5( s , s e ) I o r F e( S , S e )

me!al

(ZnrAgrln)S

n

Born i te wergneo-1n parentneses) trace-element coDtents and calculated "homogenexty' values (tn lor tttese synthet.ic (Fb,Ag)S3 0.40 wtE A9(0.78), standards are as fol-lolrs! Fe(S,Se): 0.17 !rtt (zn,A9,In)S: Se(0.66) i 0.114 wtB Ag(0.46) ?nd 0.119 ntg In(0.39)i cua(Fe,zn)qsR3 0.I5 wtB zn(0.40)i (Zn,Fe)S had 5.4 wbt Fe. Cu4Feq(S,se)a:0.15 wtA Se(0.55). th6 fol1ow-in-gstandards (Elba), were used foi b-ackgroind corrections: Cu4Fe5SB and PbS, ZnS and (Zn,!'e)S, pyrite Cu5E'eS4.

PROTON-MICROPROBE ANALYSIS OF TRACE ELEMENTS IN SULFIDES TABT.E 2b.

X-R"AY LINES

AND STANDARDS USED EOR MICRO-PXXE X-!ay

l.llneral

AgKo

(Pb,Ag) s

GaIena

li.nes SeKd

(Zn,Fe,Ag,In)S serieg

ChaLcopy!ite and bornite

"

Fe(S,Se) or c u 4 F e 5( s r s e ) 8

rSee

discussion. T!ace-elenent conieotg given standards are beLow TabLe 2a, as q o l r e c t i ons. standards f o r used backgrgund

the ore microscopeand an SEM in order to locate inclusion-free areasfor the proton-microprobe analyses. Electro n-microp ro be onaly ses A Materials Analysis Company (MAC) model 400 electronmicroprobe was usedto obtain the iron content of the sphalerite and the antimony content of the galertaas well asto verify the proton-microprobe results, wherg applicable.For quantities abovethe detectionlevdlsby electronmicroprobe, we were able to either conlirm the proton-microprobe results or to reject them owing to contaminationfrom adventitious inclusionsbelow the surfaceof the polished section. All the analyseswere performed at 25 kV, with exception of the galenaanalyses,which were carried out at 20 kV, according to analytical procedures describedby Cabri & Laflam:ne (L976).The X-ray linesand gtandardsusedare listed in Table 2a. Raw data were rEducedwith a locally modified version of EMPADR VII (Rucklidge & Gaspanini 1969). The standardsweretestedfor homogeneityaccording to the homogeneitytest of Buseck& Goldstein 3.

CALCULATED DAPIIIS

Uatlix eleBeot

Se Se Se Se Se Ag Ag A9 Ag A9 Ag ln In In In Io rcalculated

PbS ZnS (Zn,Fe) S Fes FeS, PbsZng (Zn,Ae) S FeSt fesCuFeS, PbSZoS (znrFe) S FeS2 FeS

f,or

OF X-RAY

al abaorbe! (!n) thicknese

( Z n , F e , A g, 1 n ) S series

Penetlation (!n) alepthr

JI

1050 750 750

49 49 4A

for rel1

these synthetic of as tbe list

(1969),in which a standardis consideredhomogeneous if f/