Black Ores" from Frobisher Bay, Northwest Territories"

Canadian Mineralogist Yol. 24, pp. 259-263(1986)

PRECIOUSMETALS IN MARTINFROBISHER'S "BLACK ORES''FROM FROBISHER BAY, NORTHWESTTERRITORIES *

DONALD D. HOGARTH,lND JOHN LOOP Ottowa-CarletonCentle for GeoscienceStudies, Department of Geology"University of Ottawa, Ottowa,Ontario KlN 6Ns

ABSTRACT lesanalyses de plusgrosses quantites pourraient €tre dues i I'introductionaccidentelle de plomb argentifdre dans les During the second and third Frobisher expeditions to dchantillonsi traiter. Baffin Island and vicinity (1577and 1578),small assayfur- (Traduit par la R€daction) nacesfor control of exploration wereset up near the present community of Frobisher Bay and, back in England, larger Mots-cl4s:or, argent,Frobisher, lle deKodlunarn, absorp- furnacesinstalled in the London area for bulk assayof the tion atomique,essais €lisab6thains, Territoires du Nord- 3'black qre". Assayswere madeby lead-fusion extractions. Ouest,ile de Baffin. Parting was by HNO3 (small tests) and sulfidation of sil ver (large tests). The precious-metal determinations sug- gestedsilver potential, with Ag exceedingAu in weight and' INTRoDUcTIoN for most determinations,in contemporary monetary value. Twelve new analyses(by atomic absorption) show that the The first mines in Canada were the Frobisher 5-14 ppb Au "black ores" of Kodlunarn Island contain trenchesin and near Baffin Island. From these, 14@ 5-175 ppb AB, which are severalorders of magnitude and of prospectivegold ore werereturned to the lessthan those reported by MessrsSchutz, Burcott and tonnes Denhamin the l6th century. The discrepanciesare probably British Islesin 1577and 1578.The very first exca- due mainly to mistakes in analytical procedure by the vations were those of the Countessof Warwick mine Elizabethanassayers, althoueh appreciablesilver in the later on Kodlunarn Island, an 8-hectareislet near the Elizabethan bulk-assays may have been accidentally mouth of Frobisher Bay. Ore was taken from two introduced as argentiferous lead in the crucible charge. trenches:the "Ships Trench" neartidewater, which wascompleted inl577, and the "ReseryoirTrench" Keywords: gold, silver, Frobisher, Kodlunarn Island, nearthe centreofthe island,operated in 1578.After assays,Northwest Ter- atomic absorption, Elizabethan supplying 220 tonnes of ore, Countesseof ritories, Baffin Island. "The Warwick myne fayledbeing so hard stoneto breke" (Stefansson1938, vol. 2, p.70). SovrNalrns Considerableliterature, in scatteredsources, exists on the Frobisher voyagesand, fortunately, most has Au cours des deuxibmeet troisidme expdditions de Fro- beenassembled by Stefansson(1938). Official papers bisherd I'ile de Baffin et aux r6gionsavoisinantes' en 1577 of the Cathay Company, which was assigned to et 1578,des petits fourneaux pr€ws pour essais,afin de operatethe mines, are preseryedin the Public Record guider I'exploration, furent construits prbs du village actuel Office, London, and a copy of about l8Z, made de Frobisher Bay. Des fours i plus girandecapacit6 furent for Craven Ord, is kept in the British Library (MS-l' pour I'analysedu install& dansla rfuion de Londres "mine- A ship's log of the third voyage was grossesquantitds. Les essaisse faisaient par references). rai noir" en published (1981).However, until 1984, fusion avecdu plomb et s6parationpar acide nitrique (tests by Kenyon d petite €chelle) et par sulfuration de I'argent (tests e plus few mining or geological data were available on this grande 6chelle).Les ddterminations desteneurs en m6taux interesting occurrenceof historical interest. A petro- prdcieux montraient un potentiel pour de I'argent, qui sur- graphic description of a single specimen of passartI'or en poids et, dansla plupart descas, en valeur amphibole-rich"black ore" has beenpublished by mondtaired l'€poque. Douze nouvellesanalyses par absorp- Roy (1937), and the geology was summarizedby tion atomiquemontrent que le "minerai noir" de I'ile de Blackadar (1967). ppb Kodlunarn contient de 5 d 14 ppb d'or et de 5 d 175 In 1983and 1985the Departmentof Indian Affairs qui est inf6rieur de plusieurs ordres de gran- d'argent, ce and Northern Developmentsponsored a study of the deur valeurs rapport&s par messieursSchutz, Burcott aux conductedunder et Denham au seizibmesibcle. Le ddcalageserait d0 e des mining and metallurgical activities erreursdans les procdduresanalytiquc 6lisabdthaines,quoi- Martin Frobisher.This involvedboth sitevisits and que la pr6senced'une quantit6 appr6ciabled'argent dans laboratory studies.The local geologywas described by Hogarth & Gibbins (1984)'and an updatedclas- sification of the "black ores" was given by Hogarth *Publication 01-86 of the Ottawa - Carleton Centre for (1985).The presentarticle is a continuation ofthis GeoscienceStudies. project. 2s9

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IABIiE I. MM I6I3.CEIIIIRY ASSAYS CF ROCK FRd IlE ROBISf,ET BAi AREA

M. hts Aaaayer6 F@ace site saEpla ft. Aaaay (ppu).* kf6reac6B (ks) as A!

reb.12,1578. J. scbrtz h tlot€r.s bt@ l@ !8@ 138 Stef@ao! (1938),2, p. 126 r€b. 21, t578 Dr. tucott Dr. Burcott'a ho@e 50 1530 3O5 stefssoa

k. 24, 1578 J. Schutz ra Iflnterta ho@ l@ 1520 52 gtef@s@ ( f 938), 2, p. 151 Feb. 20, 1578 J. schut, h rtnterrs bo86 2OO l2l0 72 Fl, fol. 80Bt fr$"3, fol. l2A Feb. 17, 1579 J. shutu Danford 500 1060 36 8t€f,@a@ ( 1934), 2, p. f50 -, 1579 J. Scl$t, hrtford 16000 623 7 Fl, fok. 8lY - 8ZR &R.ktu

r All t!rt6 ae gle@ aqcoilttg to llre tro gtyle cel€oals. d [1 @says er6 s6@d oilgt@llt Fponed ln Loy mceB Fr long roo.

ELTZABETHANAssays The assayswere made by lead fusion. Silver was parted with HNO3 (MS-I, -2). Little is known of A brick-lined assayfurnace was setup on Kodlu- the assays.The "Book of Register" of the third narn Island in 1577 and was operated by Jonas voyage,mentioned three times in Edward Fenton's Schutzand two assistants.It wasrebuilt in 1578,and journal (Kenyon 1981),was apparentlylost on the additional furnaceswere installed, one on the south homewardvoyage MS-3). However,after appraisal side of Frobisher Bay, oppositeKodlunarn Island, of the field assays,Robert Denham noted that the and another on the north side, to the northeastof overall lading of the third voyage could be expected the island. Robert Denhamand four assistantswere to run "almost an onseof gold in C I cwt] of ewer" assayerson this third voyage (MS-l). (MS-4). Furnacesin London producedthe first assaysfrom the secondvoyage. Precious metals were extracted by lead fusion and parted mainly with HNO3. td Giovano-Battista Agnello, a Venetian living in Lon- don, and Jonas Schutz and Burchard Kranick (a/. Dr. Burcott), two Saxonimmigrants, were the principal assayers. AJ ' ' The later and larger tests were made at the Dart- &r,/ ford metallurgical plant, which,operateddiscontinu- (ppb) -(r'./ o ously from December1578 to April 1579.Here also / Or.Burcott/2nd\oyoge gold and silver were extractedby lead fusion, but silver was separatedby sulfidation. Sulfur in the first large tests ("proffes") was provided by stibnite ,/ ("antimonie") from near Saltash,Cornwall. This l06 /^ wyoge method of parting was shown to be efficient by God- ,/2rd . a dard (1678)and was later usedat the DresdenMint / \^ and described by Percy (1880, p. 367-373)and J.Schulz Hoover & Hoover (1950,p.451452). After the stib- I -v nite supplygave out, it was replacedby pyrite from Newcastle ("marchasite") and rich copper ore \,/ ("copslighe") from the Mines Royal at Caldbeck, \/ Lake District. JonasSchutz and Dr. Burcott, along 3rndvoyoge with Robert Denham of London, were the principal assayers(Stefansson 1938, 2; MS-I, -3). l04 .\ Theseassays, i.e., thoseof Agnello, Schutz,Bur- \ cott and Denham, were characteristicallyhigh in pre- v ciousmetals, with silver commonly reportedin tens of ounces,and gold in ouncesper tonne. Even with l06 the high cost of mining, transportation and refin- As (ppb) ing, the ore wa$ thought to have potential to clear a handsomeprofit. Frc. l. Gold and silver concentrationin nine l6th

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Office manuscripts(Stefansson 1938, 2, pp. 83-84, t@ 88, l2l) givefour suchdeterminations, derived from the singlespecimen collecled in the first voyage.Two setsof samples,smuggled out of Englandto Spain, A.t one derived from the secondvoyage and the other aa from the third voyage,gave negligible gold and silver €rt) a (Hume 1894,pp. 567-569,595,6&-665).Assays of 1583made from two l@Jb samplesby William Wil- liams, assay-masterof the Tower of London (MS-7), producedsilver beads measuring 0.2 and 0.3 mm in aa diameter, equivalentto I and 3 ppb, respectively. A v) A QUANTITATIVE APPRAISAL OF THE HIGH.GRADE ELIZABETHAN ASSAYS

Resultsof nine analyseswith parted gold and silver, taken from the literature, are listed in Table I and plotted in Figure 1. Samples 1-7 probably representthe Countessof Warwick mine. Samples 8 and 9 are from unknown locations in the Frobisher Bay area.Assays, as reported,have been converted I lo loo (i.e., ppm, A^ t g /-r\ into metric equivalents in equivalentto H9 \L/ r ' g/tonne). It can be seenthat all samplesgave high precious-metalassays, with silverexceeding gold. If Frc.2. Gold andsilver values of assaysshown in Figure the weights are converted to monetary equivalents I givenin poundsper tonne. For symbols, see Figure l. @lizabethan values), silver exceedsgold in all but the early assaysof Schutz(Fig. 2). As reported,the rock was essentiallya silver ore with by-product gold. rocks derivedfrom this locality and elsewhere.Our RESULTS OF OUR ANALYSES specimenswere collected in situ (K5A, K5B) and from the stockpiles(remainder). The specimenshave The Kodlunarn Island "black ores" are coarse, beenclassified as Type I (rich in Al and Mg; Cr < Ni) black, amphibole-rich rocks that are interlayered and Type 2 (rich in Ca and Ti; Cr > Ni). Type I has with biotite gneissin a Proterozoic metamorphic beensubdivided into mineral associationsa, b, c and sequence.They are also stockpiledon the island from d, as shown in Table 2. Additional information on

TABIJ 2. srLvER, coLD AlrD pr,ATntul.l coNcENTRAtIoNs rN "BLACK oRns" FRO!{ KODTUNAXNISI"AT{D

No. Rock type MLleral saoclatloo LcatloE AC Au

K5A la EbL + Pl + Bt LE sl.tu, bottm St 45 5 K5B la SbL + Pl + Bt j@!gr bottoD gI 50 5 K5c lc Eb1 + Sp1 + 0t- Loose, bottm Sl 45

K9C lb EbL + Spl + Pl looae, bott@ RT 135 l0 K9D lb BbL + Spl + Pl looee, top Rl Lt) l0 <5 K9E ld Ebl + Opa + P1 looae, top Rf 90 T4 K8A ld Hbl- + Opx + Pl Loose, top ST 25 <15 <5

Ft22 lal Ebl. + oF + Pt Looae, top Sf, 40 <15 FB30 ld Eb1 + Opx + Pl l-ooae, top S <75 <20 FB6 2 Eb1+Cpa+Bt+lL Loose, top ST l4 FB54 2 ml +Cpx+Bt+n looae, top Sl 40 <15

Abbrevlatlo$: Bt biotlte, Cpx elimpyroxere, EbL honblender il- lloerite, oL -reseryolr" olivLne, Opx orthopyroxene, P1 plagioclce, 8p1 eplneli Rf treqch' sE ahLpta tretrch. < for Ar and Ag sigtr1ftee belw deteEl.mtlm llElt; oLtriN deterDltrallon LlEit baseal on l0 grm smple reLght. A11 value8 tu ppb: Bock Types: l, A1 and ltg-rlctr, Cr \< Nl, eubdtvLsloE a, b, c, al Lndlcate DiEeral- ssocLatlore u Ln oll@ 3; 2, Ca-ed Tl-rLch, Cr > Ni.

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the occurrence and specimens can be found in It can at once be appreciatedthat thesevalues are Hogarth & Gibbins (1984)and Hogarth (1985). much lower than the Elizabethan determinations Resultsof our analysesfor gold and silver, along (severalorders of magnitudeas shown in Fig. 3a). with samplelocation and mineral associations,are Insufficient samplesprevent any generalization on shown in Table 2. In addition, four samplesfrom Au-Ag characteristicsof the various types of "black the Kenyon collection, Department of New World ore" (Fig. 3b). Archeology, Royal Ontario Museum (F86, F822, In order to eliminate the possibility that platinum F830, FB54)were assayed; data are includedin the has been confused with gold and silver in the early table. analyses (the element was not recognized at that Gold and silver were extracted from the sample time), six sampleswere analyzedfor PGE at the matrix with an aqua regia digest, and then treated NuclearActivation Services,McMaster University. with HF to eliminate silica. The preciousmetals were Thesevalues are also reported in Table 2, but are then precipitatedby reductionoftellurium chloride very low in comparisonto the ElizabethanAu-Ag to tellurium by stannouschloride. The precipitate values. was redissolved,and the concentrationof precious metals determined by atomic-absorption spec- DISCUSSION AND CONCLUSION troscopy (AAS) using a graphite furnace. The method is similar to that described by Fryer & The strikingly high Au-Ag values of the Elizabe- Kerrich(1978), who reporteda detectionlimit of 0.18 than assayersare difficult to explain. The fact that ppb gold on a 30-gsample (based on 2o); no value Jonas Schutz (the assayer)and Michael Lok (the is statedfor silver. We believeour detectionlimit to organizer and one of the chief sponsors of be 2 ppb based on a l0-g sample. We used the Frobisher'snorthwest ventures),independently, tried CANMET gold ores MA-l and MA-2 as standards. to purchaseall the ore themselves(MS-3, fols. 52-54) For MA-l the recommendedvalue is l7 .8 p'g/9, and indicatesa genuinefaith in the ore's richnessand vir- our values are 17,6 and 17.4 pglg (basedon a l-g tually eliminates deliberate fraud on the part of the sample).For MA-2 the recommendedvalue is 1.86 assayerand administrator. We are left with the ines- pg/g, and our value is 1.856pglg (basedon a 1-g capableconclusion that the assaymethodology was sample). at fault. This seemsstrange because,as shown by The relatively large samples(each about 10g) used Hoover& Hoover(1950) and Sisco& Smith(1951), in the atomic-absorptiondeterminations are con- the art of fire assayingwas well developedby the sideredmore representativethan the small samples 1570sand closely resembledfire assayingtoday. used in direct-currentplasma (DCP) and nuclear- There is, however,the possibility that someof the activation analysis (NAA) determinations, listed by silver can be attributed to additivesin the charge. Hogarth & Gibbins (1984).Data are plotted in Figure Stibnite running 9C0ppm Ag, which was specifically 3. Valuesgiven as maximum (<) are assignedhalf- mentionedas an argentiferouscontaminant by Lok maximum quotation. and others (Stefansson1938,2, p. 128), would be

l06 Rocktype ,/ Au rlo vlb ,/ (ppb) ,i; / l04 ald ,/ cl Ar ,VY . a (ppb) AV /,rW A6 lo2 newvolues rl'|ffi ---q+r

rcou ro roo loo |o2 t04 l06 Aq (ppb) As (ppb) Frc.3. New determinationsof hornblende-richrock from the FrobisherBay area:a) comparedwith 16thcenlury values, b) plotted with respectto rock type, as defined in Table 2.

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ineffectivebecause this mineral was addedin small Hocantr, D.D. (1985): Petrology of Martin amount during the parting stage.A more likely can- Frobisher's "black ore" from Frobisher Bay, didate would be lead, which was added in large N.W.T. Geol.Assoc. Can. - Mineral.Assoc, Can. amounts to the crucible charge. Program Abstr. 10, A2,8. Argentiferous lead would have a specialrole in the & GIssrNs,W.A. (1984):Martin Frobisher's later, lower-grade assays. Consider the largest "gold mines" on Kodlunarn Island and adjacent Elizabethanbulk assay(16,000 kg; No. 9 of Table Biffin Island,Frobisher Bay, N.W'T. Contr. Geol. 1). From this samplea total of 330oz (Troy) Ag and Northwest Territories l' 69-78. Au were extractedin two tests.A samplingof the & HoovBn,L.H. (1950\:Georgius Agri- that it contained 3 oz (Troy) Au Hoovnn,H.C. lot suggested De Re Metallica. Dover Publications, New (MS-l). ppm cola: The ore, therefore, averaged600 Ag York. and 6 ppm Au. This is about 10,000times higher in Ag and 1000times higher in Au than the averageof Hurras,M.A.S., ed. (1894):Letters and statepapers our determinations. relatingto Enetishaffalrs, preservedin the Archives Lead consumedin thesetests commonly surpassed, of Simancas,(1569-1579). British National by a factor of2, the weight ofthe ore assayed,and Archives,London. it is conceivablethat the bulk of the silver was ac- KBNvoN,W.A. (1981):The CanadianArctic journal of cidentally added as argentiferous (300ppm Ag) lead Captain Edward Fenton, 1578. Archivaria lL, and litharge in the crucible charge. This is not an l7t-203. improbable composition, especiallyfor lead derived (1980):,Metallurgy: the Art of Extracting region ofthe northern Lake Pencv, J. from the silver-bearing Metals their Ores, Silver and Gold, part I. possibility that frorn District (MS-l). The exists,therefore, John Murray, London. at least some of the silver can be ascribedto an enriched additive in the Dartford tests. Rov, S.K. (1937): The history and petrology of Frobisher'sgold ore. Field Museum Nat, Hist. (Chicago),Geol. Ser.7Q),21-38. Aclo,lowleoceMENTs Srsco,A.G. & Srrarrn,C.S. (1951):Lazarus Erker's Treatiseon Oresand Assaying(translatedfrom the Researchwas suppofied by a DIAND contract. German edition of ,1J80l. Univ. Chicago Press, Walter Gibbins of DIAND organizedthe field visit Chicago. (D.D.H.) field and accompaniedone of us during SreFANssol',r,V. (1938): The Three Voyagesof Martin work at Kodlunarn Island. This trip was facilitated Frobkher (2 vols.\' The ArgonautPress, London' by the advice of Walter Kenyon. Four specimens FB54) were provided by Peta (F86, FB22, F830, Manuscripts Daniels from the Kenyon collection at the Depart- ment of New World Archeology, Royal Ontario MS-l [576-1580;Exchequer Court papers 9f !!9,C-on- Museum. MS-5 and -6 weretranslilerated by Profes- pany of Cathayl. British Library, Add. 39852. sor Elliott Rose,Depa.rtment of History, University of Toronto. Accessto the Cecil Papers, Hatfield MS-2 11578;Edward Sellman'saccount of the third marginalnotes, House, Hertfordshire, was provided by the Marquess Frobishervoyage, with significant wereomitted from the publishedversionsl. of Salisbury. The manuscript was improved through which British Library, Harleian, 167' 165-180. the suggestionsof two anonymous referees.The authors are grateful to Julie Hayes for typing the MS-3 lno date;Anonymous 16th century criticism-of manuscript and Edward Hearn for drafting the illus- Frobisher'sconductl. Public Archivesof Canada, trations. M.G.40,Cl, No.20. M. Lok to Lord Burshlev]'Hat- RSFERENcES MS-4 [Oct.10, 1578; field HouseMS' 161'(71). Blecrapan, R.G. (1967); Geological reconnaissance, MS-5 [Jan.13, 1579: E. Fentonto PrivyCouncil]' Pub- southern Baffin Island, District of Franklin. Geol. lic RecordOffice, SP 12, 129' (6). Sum. Can. PaP.66-41. MS-6--ha;I. [Jan. 13, 1579:E. Fentonto SecretaryWalsing- Fnvrr., B.J. & KeRRrcH,R. (1978): Determination of Public RecordOffice, SP 12, 129,Q)' precious metals at ppb levels in rocks by combiled wet chemical and flameless atomic absorption MS-6 [Jan. 13,1519:E. Fentonto SecretaryWalsing- method. Atomic Absorption Newsletter 17,4-6. haml. Public RecordOffice' SP 12, 129' (7).

Golnano, J. (16?8): Experiments of refining gold with ReceivedJuty 20, 1985,revised manuscript accepted antimony. Phil. Trans. 12, 953-961. November13, 1985.

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