Carlin Trend Exploration History - Discovery of the Carlin Deposit

7/27/2019 Carlin Trend Exploration History - Discovery of the Carlin Deposit

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1968 view of the early developments at the Carlin mine , looking southwest.n the left foreground o n the back cover. Newmontphoto .


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UNIVERSITY OF NEVADA, R ENOMACKAY SCHOOL OF MINES

NEVADA BUREAU O F MINES AN D G EOLOGYSPECIAL PUBLICATION 13

Carlin Trend Exploration History:Discovery of the Carlin Deposit

J . Alan CoopeNewmont Exploration Limited

For more informationcontact:Nevada Bureau of Mines and GeologyEmail: [email protected]: http://www.nbmg .unr.edu/


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IntroductionThe Carlin mine, owned by Newmont Gold Companyand located in the northern part of Eureka County,Nevada, commenced production in April 1965. Orereserves at the beginning of operations were 11 milliontons averaging 0.32 ounces of gold per ton. The Carlinmine had produced a total of 3.2 million ounces of goldwhen mining was suspended in 1986.The Carlin gold deposit is hosted within the Silurian-Devonian Roberts Mountains Formation and has a mostprobable age of between 37 and 14 Ma bracketed by theintrusion of early Oligocene dikes and the extrusionof Miocene volcanics (Kuehn, 1989). The well-beddedRoberts Mountains unit is part of a lower and mid-Paleozoic miogeosynclinal sequence exposed within theLynn tectonic window. The window is surrounded on

three sides by eugeosynclinal rocks of Ordovician,Silurian, and Devonian age which were moved into posi-tion along the major Roberts Mountains thrust during thelate Paleozoic Antler orogeny.The mine was the first large development along what isnow known as the Carlin trend-a northwesterly trendingbelt of mineral deposits over 50 miles long and 5 miles wideextending through northern Eureka County into ElkoCounty on the northwest and southeast (fig. 1). Subsequentdiscoveries and developments along the Carlin trend haveled to the identification of over 20 deposits with existinggeological resources of gold estimated at approximately 69million ounces including mineable reserves of 40 millionounces. The Carlin trend has the potential of becoming thelargest gold-producing district in North America.

FIGURE .-Locations of mines (X) and other significant deposits ( e ) along the Carlin trend,Eureka and Elko Cou nties, Nevada.


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Early ProspectingThe earliest prospecting in the Carlin area was in the1870s when the Good Hope claims were located in the

Maggie Creek district 11 miles northwest of Carlin. Themost important metals mined from the vein structures onthese claims were lead and silver in association with bariteand minor gold.The first principal gold discovery in the region wasmade by Fred Lynn in placers on Lynn Creek in 1907 at alocation approximately 1.5 miles north of the present siteof the Carlin mine (Vanderburg, 1936). Subsequent workled to the discovery of additional placer gold in Sheep,Rodeo and Simon Creeks (fig. 2). The major productionfrom these deposits occurred prior to World War I1 but

some of the last placer miners were still at work in theearly 1960s. Total gold production from the placers isestimated to be at least 7,500 ounces and may havereached 10,000 ounces (Vanderburg, 1936; Roberts andothers, 1967). The bedrock source of this gold has beentraced to a series of narrow quartz veins and stringers inshattered zones sporadically distributed within thedrainage areas. The best known of these bedrock occur-rences is the Big Six mine in the headwaters of Lynn andSheep Creeks (Roberts and others, 1967). Despiteattempts continuing to this day, only very limited produc-tion has been won from any of these lode occurrences(Vanderburg, 1938).

0 4000 Feet,IFIGURE.-The present location of the Carlin mine and the locations of Lynn, Rodeo, Sheep, and Simon Creekswhich were worked for placer gold prior to discovery of the Carlin deposit.


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The Significance of Invisible GoldIn marked contrast to the nature of these early golddiscoveries, the Carlin trend deposits that are currentlybeing extensively mined are characterized by very finegold-sometimes referred to as "micron-sized gold" o r,mo re topically, "invisible gold. "Virtually all the gold in these deposits is so fine tha t itcan not be concentrated by panning. T he old-timers whoworked solely with the gold pan were therefore at adistinct disadvantage and, although they must havepanned most of the creeks draining the TuscaroraRange no rth an d sou th of the Lynn district placers, theyfailed to detect any significant indications of themillions of ounces of Carlin trend gold that have beendiscovered by more appropriate or more sophisticated

methodology du ring the past 45 years. Not th at they didnot find the occasional color-there was som e placeractivity in the Maggie Creek area in these earlyyears-but the am ou nts recovered were minor and total-ly disproportionate to the presently known resources inthe Gold Quarry-Maggie Creek region (Vanderburg,1936).Many people are under the misapprehension thatNewmont geologists were the discoverers of "invisiblegold" in the early 1960s. This is untrue. Th e earliestrecords of very fine gold in the western United Statescome from the Mercur mine located just a few milessouth of the Bingham Canyon copper mine in Utah.Originally located for silver, the gold in the Mercurdistrict was first detected by fire assaying in the 1880s.Ironically but significantly, in the early history of thisca m p there is a record of legal action against an assayerin Salt Lake City brought by miners who could not con-firm the presence of gold o n the property using the goldpan (L. Kornze, personal commun.).In Nevada, invisible gold was recognized at GoldAcres in Land er Co unty several years prior to the initialproduction from this property in 1936 (Vanderburg,1939). The first gold discoveries at Maggie Creek (theMaggie group) in Eureka County were made in 1925,an d six cars of ore averaging 0.42 oun ces of gold per tonwere shipped in 1936 (Vande rburg, 1938). Th e Potosimining district in the Osgood Range in HumboldtCounty was established in the 1870-1880 period andsom e min or tungsten was produced in 1917-1918. It

was not un til 1934 tha t prospectors fire assayed samplesfrom the sil iceous outcrops and discovered gold at thepresent site of the Getchell mine. As reported by Ha rdy(1941), this gold was found to be invisible and refrac-tory and undetectable by panning although detailedwork by Joralemon (1951) records coarser gold in thedeposit. Fine-grained gold was also discovered at theGold Standard mine in Pershing County in 1934. Anearlier discovery of fine-grained gold may have beenmade at the Bu ffalo Valley Mines Com pany property inLander County. Prospectors passed through theBuffalo Valley district in the 1860s bu t the gold was notidentified until outcrops were sampled at the prop erty in1912.During the 1930s, W . 0 . Vanderburg, a mining engi-neer with the U.S. B ureau of Mines, began documen tingactivity in hardrock gold and placer mining in north-east and central Nevada. It was Vanderburg's (1936,1938, 1939) observations that stimulated the initial in-quisitiveness tha t eventually led to Newmont's par-ticipation in the rebirth of gold mining in the state ofNevada.Vanderburg (1939) noted that at Gold Acres it was"impossible to distinguish between o re and waste exceptby assay, and gold is present in such a state that it isimpossible to obta in a single color by panning." In thefinal paragraph of his report, Vanderburg (1939) re-emphasized tha t "sedimentary gold deposits d o notpossess easily recognizable indications" an d would havebeen passed over in former years by prospectors whodepended largely o n panning. In addition to citing theGold Acres mine as one of these sedimentary deposits,he also referred to the Getchell mine in HumboldtCounty, the Standard mine in Pershing County, andother deposits , some of which are now known to haveyielded coarser gold. Vanderburg (1939) predicted,however, that other deposits similar to Gold Acresremained "to be discovered in Land er County and otherareas in the State, where sedimentary formations, l ike

shale and lim estone lying in proximity t o acid intrusives,are common."John Livermore, a geology graduate from Stanford,first read Va nderburg's predictions in the late 1940s andwas deeply impressed by the exploration possibilities.


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Newmont's Gold Exploration ProgramAlthough gold was not in vogue as an exploration andmining target in th e 1950s, the search for an d develop-ment of base metals, particularly porphyry copper

deposits in the western United States, was intenselycompetitive. This industry, over the years, has beenrevolutionized by new technology and th e developmentof new mining and metallurgical methods, and thegrades of copper that could be profitably mined pro-gressively decreased as the scale of operations grew.Newm ont actively participated in these porphyry c opperdevelopments, and Newmont executives, particularlyRobert (Bob) B. Fulton, Fred Searls, Jr., and PlatoMalozemoff, began to think of a similar evolution in thegold industry through open-pit mining followed byrelatively cheap but highly efficient cyanide extraction.Concurrently with these developing ideas, the U.S.Geological Survey was adva ncing its regional geologicalmapping a nd related studies of Nevada stratigrap hy andStructure.Ralph J. Roberts and other USGS geologists com-menced regional synthesis and mapping studies inNevada in 1939. Th e Roberts Mou ntains thrust was firstrecognized in the Roberts Mountains area northwest ofEureka (Merriam and Anderson, 1942). By the late1940s and the early 1950s, the USG S mapping programhad been extended to cover several quadrangles in theWinnemucca, Golconda, Mount Tob in, Mount Moses,and the Antler Peak areas of central and northeasternNevada (Roberts, 1986).Roberts' (1951) work at Antler Peak led to the rec-ognition of the Antler orogeny, and later regional cor-relations permitted the USGS to extend the RobertsMoun ta ins th rus t f rom Eureka on the eas t toManhattan on the south and to Mountain City on thenorth (Roberts, 1986). Roberts and Lehner (1955)mapped the C arlin, Lynn, and Bootstrap windows andthey presented their interpretations at a GeologicalSociety of America meeting in 1955. It was during thispresentation th at they identified the northwestern align-ment of the lower plate carbonate windows between

Eureka and Battle Mountain (the Battle Mountain-Eureka belt) and the Bootstrap and the Copper King(the Lynn-Railroad belt)-now more popularly referredto as the Battle Mountain trend and the Carlin trend.Roberts and others (1958) published a comprehensivesummary of the USGS mapping program through northand central Nevada. Figure 3, adapted from that paper,depicts the extent of the Roberts Mountains thrust, thedistribution of the upper plate rocks, an d the alignmentof th e lower plate windows.Following publication of Roberts' (1960) Profession alPaper on the alignment of base and precious metalmineral districts in northe astern Nevada and their rela-

tionship to major thrust faults (fig. 4), Newmontgeologists began to take full advantage of the USGSmapping a nd geological interpretations.In early 1961, John Livermore of Newmont wasmanaging a drilling program on the silver/base-metaldeposit at Ruby Hill in Eureka on behalf of a syndicateof mining companies. Through various contacts andperiodic examinat ion of the Eureka Courthouserecords, Livermore was able to monitor the variousprospecting and mining developments in Nevada.Contact was made with USGS personnel active in themapping programs. H e also visited the "Big" GoldAcres mine in Lander County and spoke with themanager, Harry Bishop. Mr. Bishop expressed theopinion tha t a favorable area for the discovery of addi-

tional fine gold deposits was not in nearby LanderCounty but in northern Eureka County.In the spring and summer of tha t year, Ra lph Robertsdelivered several talks throughout the state on theregional stratigraphy and structure in northeasternNevada an d the alignment of the mineral districts. Jo hnLivermore attended one of these talks in Ely and , after-wards , met with Roberts to discuss these geological rela-tionships in more detail.Meanwhile, Newmont's Nevada gold explorationprogram had commenced in March 1961 in the BattleMountain region where Alan Coope was investigatingthe potential of the Marigold and the Buffalo Valleyproperties near Valmy. These investigations revealedtha t neither of these properties had mine potential withgold at $35.00 per ounce. Based on a recommendationby John Livermore, however, Newmont had decided toproceed with an exploration program in Eureka andElko C ounties to prospect the Roberts M ountains thrustzone for fine-grained gold deposits and, in an initialmove, had secured verbal permission to examine theMaggie Creek prospect, 8 miles northwest of Carlin(also known at that time as the Maggie group and/ or theGold Quarry mine), in May 1961.When the Ruby Hill drilling was completed,Livermore and C oope were instructed to meet in Carlinand proceed with the E ureka-Elko Counties program.The date was Jun e 1961.At this time, there was only limited mining activity inthe area north of Carlin, principally at the Bootstrapand the B lue Star mines (fig. 5). Since the early historyof these properties chronicles numerous events and dis-coveries relevant to the commercial evolution of theCarlin trend, a brief review of these historical develop-ments is appropriate.Antimony was discovered at the Bootstrap propertyin 1918, but it was not until 1946 that Fran k M aloneycollected samples for fire assay and identified gold on


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OREGON

Inferredorfgfnal boundary

0

/ - 0"118"0 30 M ~ l e s-

rans~t~onalssemblage(parautochthonous)Eastern assemblage(parautochthonous andautochthonous)

117' 116"[CURE 3.-Map of north-central Nevad a showing outcrop areas of w estern assemblage (upper plate), easternassemblage (lower plate), and transitional assemblage rocks and the extent of the Roberts Mountainsthrust (adapted from Roberts and others, 1958).

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FIGURE.-Distribution and alignment of Pa leozoic facies, granitic rocks, and principal mining districtsin Eureka Co unty, N evada, and adjacent areas (adapted from Roberts, 1960).

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this property (Ryneer, 1987). The first gold production(100 tons averaging 0.65 ounces of gold per ton) wasachieved in 1948. When Marion Fisher of Battle Moun-tain acquired a lease and option on the property inOctober 1955 from the Modoc Mine and ExplorationCompany, workings included a 535-foot tunnel drivenby the Getchell Mines Company in 1949 which failed tointersect any ore of commercial value, a 24-foot shaftand two deep open cuts. Mr. Fisher invited RobertTaylor of Battle Mountain and Harry Treweek of GoldAcres into equal partnership in his Bootstrap lease andan agreement was negotiated with the HomestakeMining Company which conducted additional explora-tion in the summer of 1956. Homestake subsequentlyterminated this agreement and 13 other companiesdeclined the invitation to participate in further work onthe property before a mining and milling agreement wasconcluded with R. R. Reed of Fallon, Nevada inJanuary 1957.During the next 3 years a 100-ton plant was completedand, despite numerous difficulties, total productionfrom the Bootstrap through early 1960 was 40,000 tonsof $1 1OO rock, from which between 10,000 and 11,000ounces of gold were recovered. (Marion Fisher, per-sonal commun.) This was, by far, the largest gold pro-duction from a lode deposit along the Carlin trend tothat time. In June 1961, the property was under optionto a construction contractor from San Francisco, butthere were operational difficulties and the property wasidle.Initial development at the Blue Star mine (also knownas the No. 8 mine) was for turquoise in the 1920s(Ryneer, 1987). Open-pit and shallow underground pro-duction of good quality turquoise continued inter-mittently until the property's added potential wasdiscovered by Marion Fisher who first identified gold inthe workings in 1957. By 1961, the property had beenoptioned from the owners, the Edgar brothers of BattleMountain, by M M and S Mining, a Carson City-basedcompany. In turn, M M and S had leased the propertyto Combined Production Associates, an operating com-pany financed by Blake Thomas of Salt Lake City.Bill Lage, Bob Morris, and Ralph Scott of M M and Shad drilled some holes into the Blue Star turquoiseworkings in 1960 and obtained values up to 0.44 ouncesof gold per ton over 10 feet in percussion samples.Channel samples from some of the deeper workingsassayed up to 0.65 ounces of gold per ton over 5-footintercepts. None of this gold was pannable (Bill Lage,personal commun.).Combined Production established a 200-ton cyanidemill on the property after acquiring used equip-ment from a number of nearby mining locations.Unfortunately, in early 1961 they encountered serious

operating problems with slimes in the ore, and their pro-duction totalled only four 200-ounce dort bars. Sub-sequently, several major mining companies were con-tacted but none expressed any interest in the property.John Livermore visited the Blue Star after his conversa-tion with Harry Bishop at Gold Acres. Following anexamination and a discussion with Bill Lage, Livermorerecommended to Fred Searls, Jr. that Newmont shouldmake a careful evaluation of the Blue Star property.Fred Searls contacted Blake Thomas and the arrange-ments were made. So when Livermore and Coopearrived in Carlin in June 1961, they had the MaggieCreek claims to explore and the Blue Star mine toexamine.The Blue Star examination extended over three weeksand consisted of detailed geological mapping and exten-sive sampling. All samples were fire assayed by HarryTreweek, an experienced assayer with a laboratory inGold Acres, some 50 miles from Carlin. The resultswere favorable. The deposit was estimated to contain atleast 500,000 tons of bulk-mineable ore averaging0.15-0.20 ounces of gold per ton, and Livermore andCoope recommended to Fred Searls, Jr. that Newmontacquire the property. Fred Searls negotiated withCombined Production but was unable to conclude anagreement.Livermore and Coope used their newly acquiredknowledge of the Blue Star occurrence in their evalua-tion of the surrounding area. A simple geological modelfor the Blue Star deposit had been developed in whichupward-migrating hydrothermal fluids had beenponded beneath a low-dipping thrust structure leadingto the precipitation of major concentrations of fine-grained gold. The surface trace of the Roberts Moun-tains thrust was readily mappable over the greater partof the Lynn window due to the marked differences inlithologies in the lower and upper plate rocks, and asystematic prospecting program examining the outcropsand float along this tectonic contact was initiated.Within a few weeks, anomalous gold values (in excess of0.03 ounces of gold per ton) were encountered along thetrace of the thrust in strongly silicified (jasperoidal) andbarite-veined exposures approximately 2-3/4 milessoutheast of the Blue Star. A return visit to the area con-firmed these initial indications with several grab andchannel samples assaying 0.03-0.20 ounces of gold perton. Detailed geological mapping was carried out and,at separate times, USGS geologists Ralph J. Robertsand Hal Masursky were invited to visit the area to assistin the identification of the geological formations andcollect graptolite fossils. Fred Searls and Bob Fultonreturned to the area in late September 1961 and a deci-sion was made to stake some claims. With the assistanceof Mort White, a Newmont surveyor, seventeen 20-acre


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0 lluvium an d lakebed deposits0 pper plate sequence (western assemblage)

Lower plate sequence (eastern assemblage)J~ob erts Mounta in thrust, teeth in upper plate

x x Mines and prospects."Promine nt silicified zones

. . . .. . . .

. . . .. . . .. . . .. . . .

. . . .. . . .

. . . .. . . .. . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .

Copper King mine

FIGURE 5.-Reconnaissance geolog ical ma p of the Boot strap, Lynn, and Carlin windows prepared by J . S. Livermore andJ . A. Coop e in October 1961 showing the location of active and dormant mines and prospects.

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lode claims were located in October of that year posi-tioned over what eventually became the site of the mainpit of the Carlin mine.A bulldozer was contracted to excavate trenches forthe discovery work that followed, and one trench(Trench B, fig. 6) was sited across a NNW-trendingquartz porphyry dike which was thought to be related tothe gold mineralization. Assaying of the exposures inthe trench proved the dike material to be low in gold,but the mildly hornfelsed sedimentary rocks adjacent tothe eastern contact assayed 0.20 ounces of gold per tonover 80 feet. This was the first significant discovery ofgold in the Carlin mine area.Heavy snows in late November ended the 1961 pros-pecting season soon after this discovery. JohnLivermore was promoted to Manager of Exploration,

Newmont Mining Corporation of Canada, effectiveJanuary 1962, and Alan Coope and Mort White spentthe winter on an exploration project near Pioche,Nevada.The 1962 season at Carlin began in late April. Initialwork consisted of bulldozer trenching and road buildingfor drilling programs at both Maggie Creek and theCarlin prospect. It was at this time that Bob Morrisapproached Alan Coope and advised that M M and Shad negotiated an agreement on the Popovich home-stead property adjacent to the Newmont group of 17claims (fig. 6). Morris offered the property to Newmontand, based on favorable geological knowledge of theproperty from the 1961 mapping coverage, Cooperecommended to Bob Fulton that Newmont acquire thePopovich 80 acres.

FIGURE .-Property map of sections 13 and 14, T35N, R50E showing the location of the original 17 claims,the Popovich 80 acres, and the sites of the significant gold discoveries of the Carlin deposit.

11 )/ 12(\..1

Creek..-..-.-..-,,_

Surface trace porphyry dike\

@

23

0 @\\.@

\ Location of drill hole discovery,September 1962

13Location of Trench B discovery,November 1961

240 112 Mile

+N-L@ 0 0 0 0@ @ @'.@'..0 148


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the leaching of carbon ate matrix from a silty limestone.Th e porous, unmineralized-looking rock assayed a sur-prising 0.22 ounces of gold per ton. A line of 11 drillsites was positioned by Coope across the strike of thisfault, 50 feet north and parallel to the boundary of the80 acres and the neighboring TS Ranch land.Because of a scheduled fall payment date in the M Mand S option agreement, the Carlin area drilling pro-gram commenced on the 80 acres. F or expediency, drill-ing began a t the base of the slope near Simon Creek an dprogressed upslope across the property. Th e third holedrilled, located in the immediate footwall of the faultwhere the float with 0.22 ounce of gold per ton wascollected, intersected approximately 100 feet of highlysheared and altered carbonate rocks averaging $36.00per ton (1.03 ounces of gold per ton). This was thesecond significant, and most spectacular, discovery inthe Carlin area (fig. 6). The date was September 1962.The high gold value obtained from what appeared tobe unmineralized float prompted a more extensive

sampling of float and outcrops that were, at that time,regarded as geologically unspectacular. This programidentified gold values in float u p to 2.0 ounces of goldper ton and culminated in the rapid outlining of theexposed sections of the Carlin orebody.The drilling program intensified on the Carlin prop-erty. Pete Loncar played a prominent role in thedevelopment through into production and Byron S.Hardie supervised the geological work on the projectand in the surrounding area from early 1963 onwards.Robert F. Sheldon calculated the ore reserves and F rankW . McQuiston and Paul E. Stucker were responsible forthe construction of the mill which was designed andbuilt by the Bechtel Corporation of San Francisco.Eventually 11 million tons of bulk-mineable ore wereoutlined averaging 0.32 ounces of gold per ton in astratabound deposit (fig. 7) . The Carlin mine com-menced produ ction in April 1965 at the rat e of 2,000tons per day. Total project costs through to productionwere $10 million.

The Carlin mill in a 1968photograph looking northwest. The Blue Star workings can be seen in the middle distance beyondthe main mill building. Newmont photo.

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TABLE.-Geological gold resources and reserves of the Carlin trend,December 1989 (modified after Thorstad, 1989).- -Deposit

-Total geologic gold resources Reserves

Thousands Ounces Thousands Thousandsof tons per ton of ounces of ounces

Gold Quarry/Maggie CreekGenesisPostRainPeteBlue StarCarlinNorth StarCapstone/BootstrapTuscLanternBobcatEmigrant SpringsGnomeSMZ

American Barrick2Goldstrikeoxidesulfide

Dee Gold Mining4Deemill oreheap-leach ore

Ivanhoe GoldHollisteroxidesulfide

Goldnev Resources/BarrickMaggie Creek 0.021TOTAL

'Resource calculation at December 27, 1989; cut-off grade is 0.010 oz/ton. Data derived from Newmont's December 1989 News Release.'Data courtesy of American Barrick Resources; does not include the Screamer, Ro deo, and P urp le Vein discoveries.'Reserves only.'Data courtesy of Dee Mining Co.


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Recent DevelopmentsAlthough not the first gold discovery, the Carlin minewas the first major development along the Carlin trend.Operations at the mine were suspended in 1986 follow-ing the production of 3.2 million ounces of gold over a21-year period. The geology and mineralization of the

mine have been described by Hardie (1966), Hausen andKerr (1968), Adkins and Rota (1984), Radtke (1985),Bakken and Einaudi (1986), Christensen and others(1987), and Kuehn (1989). The exploration and opera-tional success of the Carlin mine together with (a) thecumulative geological appreciation of the tremendouspotential of the Carlin trend, (b) ncreases in the price ofgold and (c) improvements in mining and metallurgicaltechnology in subsequent years has led to additionalmajor discoveries and developments by Newmont andother companies, and the Carlin trend production,gold reserves, and resources are now challenging thePorcupine mining district of Ontario as potentially thelargest gold producing district in North America. ThePorcupine camp has produced approximately 59 millionounces of gold over the past 80 years. The Carlin trendcurrently hosts an estimated 69 million ounces in

1. STRATABO UND (Carlin, Deep West)

2. STRUCTU RAL "VEIN-LIKE" (Bootstrap-Capstone)

3. STRUCTUR AL STOCKWORK (Gold Quarry)

FIGURE.-Styles of mineralization ofCarlin trend gold deposits.

TOTAL ORE RESERVES

AVERAGE RESERVE GRADEMGOLD PRODUCTION

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FIGURE9.-Total ore reserves, average grade of reserves,and annual gold production of the Carlin trend since 1965.geological resource of which 58% is classified as miningreserves (table 1). Production from the Carlin trend atthe end of 1989 totalled slightly more than 8 millionounces.Several styles of mineral occurrences have been iden-tified (fig. 8) and the graphical representations in figure9 portray annual total ore reserves, annual averagereserve grade, and yearly gold production of the Carlintrend mines since 1965.Discoveries are still being announced, and it is clearthat further development along the Carlin trend will befaced with the challenges of developing and miningdeeper mineralization and also overcoming the metal-lurgical complexities of refractory ores.


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AcknowledgementsT h i s c o m p i l a t i o n w o u l d n o t h a v e b e e n p o s s ib l e w i t h -

o u t s i g n if i ca n t i n p u t f r o m n u m e r o u s p e o p l e w h o e i t he rp a r t ic i p a t ed i n t h e e a rl y h i s t o ry o f t h e C a r l i n t r e n d orw h o h a d r e s e a rc h e d t h e h is t o r y p r e v i o u sl y . T h a n k s a r ee x p re s se d p a r t i c u l a rl y t o J o h n L i v e r m o r e w h o p l ay e d t h ep r i m a r y r o l e and t o O d i n C h r i s t e n s e n , A l l e n C o c k l e,C h a r l e s E k b u r g , M a r i o n F i s h e r, B y r o n S . H a r d i e , L a r r yK o r n z e , B i l l L a g e , P e t e L o n c a r , R a l p h J. R o b e r t s ,

References

Joe R o t a , R o b e r t R y n e e r , L i n d a T h o r s t a d , C l e m m i eT r e w e e k , P e r r y W e s t , a n d M o r t W h i t e , w h o w i l li ng l yreca l led the i r experiences or p r o v i d e d i n f o r m a t i o n con-t r i b u t i n g t o t h e a c c u r a c y o f t h i s a c c o u n t . S u g g e s t i o n s b yr ev i ew e rs J o h n S . L i v e r m o r e , H a r o l d F. B o n h a m , R a l p hJ. R o b e r t s , and J o s e p h V. Ting le y c ? nside ra b ly im pro ve dt h e m a n u s c r i p t. T h e d r a f t in g of s e ve ra l p re l imina ryf i g u r e s b y S i m o n T u t t l e i s a l s o gr a t e f u ll y a c k n o w l e d g e d .

Adkins , A . R. , and Rota , J . C . , 1984, Genera l geology of theCarlin Gold Mine, in J . L. Johnson, ed . , Fie ld t r ipguidebook, Exploration for ore deposits of the NorthAmerican Cordillera: Association of Exploration Geo-chemists , p. 17-23.Bakken, B. M., and Einaudi , M. T. , 1986, Spat ia l andtemporal relations between wall rock alteration and goldmineralization, main pit , Carlin Gold Mine, Nevada,U .S .A . , if? A . J . Macdonald, ed., Proceedings Volume,Gold '86-An international symposium on the geology ofgold deposits : To ron to, p. 388-403.Christensen, 0 . D. , Knutsen, G. C. and Ekb urg, C . E. , 1987,Disseminated gold deposits of the Carlin Trend, Eurekaand Elko Counties, Nevada: Society of Mining Engineersof the American Institute of Mining and MetallurgicalEngineers Preprint 87-84, p. 7.Hard ie, B. S., 1966, Carlin gold mine, Lynn district, Nevada,in Papers presented at the AIM E Pacific Southwe st MineralIndustry Conferen ce, Sparks, Nevada, May 5-7, 1965:Nevada Bureau of Mines Report 13, p. 73-83.H a r d y , R . A., 1941, Geology of the Getchell Mine: Tr ans-actions American Institute of Mining and MetallurgicalEngineers, v. 144, p. 147-150.Hausen, D . M., and Kerr , P . E. , 1968, Fine gold occurrence a tCarl in , Nevada , in J . D. Ridge , ed . , Ore depos i ts of theUni t e d S ta t e s , 1933-1967 (Gra ton -Sa le s Vo lume ) :American Institute of Mining and Metallurgical Engineers,V. 1, p. 908-940.Jorale mon , Peter, 1951, The occurrence of gold at the GetchellMine, Nevada: Economic Geology, v. 46, p. 267-310.Kuehn, C. A., 1989, Studies of disseminated gold depositsnear Carlin, Nevada: Evidence for a deep geologic settingof ore formation [Ph.D. thesis]: Pennsylvania StateUniversity, 395 p.Merriam, C . W., and Anderson, C . A, , 1942, Reconnaissancesurvey of the Roberts Mountains, Nevada: GeologicalSociety of America Bulletin, v. 53, no. 12, p. 1675-1728.

R a d tke , A. S., 1985, Geology of the Carlin gold deposit: U .S.Geological Survey Professional Pap er 1267, 124 p.Roberts , R. J ., 1951, Geology of the Antler Peak Quadrangle,Nevada: U.S. Geological Survey Geological QuadrangleM a p GQ-10, scale 1:62,500.Roberts , R. J ., 1960, Alinements of mining districts in north -central Nevada: el .S. Geological Survey Professional Pape r400-B, p. B17-B19.Roberts , R . J., 1986, The Carlin story, in Sediment-hostedprecious-metal deposits of northern Nevada: NevadaBureau Mines and Geology Report 40, p. 71-80.Roberts , R . J . , Ho tz , P . E . , G i lluly, J . , a nd Fe rgus on , H. G .,1958, Paleozoic rocks of north-central Nevada: AmericanAssociation of Petroleu m Geologists Bulletin, v. 42, no. 12,p. 2813-2857.Roberts , R . J . , and Lehner , R . E. , 1955, Addi t ional da ta o nthe age and extent of the Roberts Mountains thrust faultnorth-central Nevada: Geological Society of AmericaBulletin, v. 66, no. 12, pt. 2, p. 1661.Roberts , R . J . , Montgomery, K ., and Lehner , R . , 1967,Geology and mineral resources of Eurek a County, Ne vada:Nevada Bureau of Mines Bulletin 64, 152 p.Ryneer, Robert, 1987, History of mining along the CarlinTre nd , in J . L . J ohns on a nd E . Abbot t , eds . , Guidebookfor field trips, Bulk m ineable precious metal deposits in thewestern United States: Geological Society of Nevada,April , 1987.

Tho rstad , L. E. , 1989, Carlin Trend gold belt: The producers:Mining Magazine, October, 1989, p. 263-67.Vanderb urg, W . O., 1936, Placer mining in Nevada: Universityof Nev ada Bulletin, v. 30, no. 4 [Nevada Bureau of Minesan d G eology Bulletin 271, 178 p.Vanderburg, W . O., 1938, Reconnaissance of mining districtsin Eureka County , Nevada: U.S. Bureau of Mines Infor-mation Circular 7022, 66 p.Vanderburg, W. O., 1939, Reconnaissance of mining districtsin Lander County , Nevada: U.S. Bureau of Mines Infor-mat ion Circular 7043, 83 p.


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The Nevada Bureau of M ines and G eology (NBMG ) is part of the M ackay Schoolof Mines at the University of Nevada, Reno and is the state geological survey.NBMG scientists conduct research and publish reports on mineral resources andvarious aspects of general, environm ental, and engineering geology.Current activities in mineral resources and general geology include detailedgeologic mapping a nd stratigraphic studies in Nevada, com parative studies of bulkmineable precious-metal deposits, geochemical investigations of mining districts,resource assessments, igneous petrologic studies, hydrothermal experiments,research on the origin of hydrothermal platinum-group-element occurrences, andexamination of the origin and distribution of borate deposits in Nevada.Environm ental, engineering, and urba n geology projects include investigations ofearthquake hazards and related aspects of neotectonics, examination of issuesinvolved in siting nuclear and hazardous wastes, mapping of geomorphic features,radon hazard studies, studies of landslide hazards, and investigation of landsubsidence in Las Vegas Valley.Geologic information activities include creating an d up dating databa ses on m iningdistricts, active mines and prospects, a nd geothermal an d petroleum exploration an dproduction; implementation and development of statewide geographic informationsystems; and maintenance of core and cuttings facilities, rock and mineral collec-tions for research, aerial photographic imagery and maps, and extensive files onNevada geology and resources.NBM G cooperates with nume rous state and federal agencies in providing geologicand resource information and in conducting research. Research results are publishedas NBMG bulletins, reports, maps, and special publications as well as in federalpublications a nd scientific journals. In ad dition to addressing the needs f or geologicinformation by conducting research, publishing reports and maps, and creatingcomputer databases, staff members assist the public, industry, and governmentagencies by answering specific questions regarding Nevada geology and resourcesan d by providing some chemical and m ineralogical analyses.Individuals interested in N evada geology are encouraged t o visit o r write NBMGor call (702) 784-6691. NBMG offices are located in the west wing of the ScrughamEngineering-Mines Building on the University of Nevada, Reno campus. Whenvisiting NBMG by car please stop at the information booth just inside the CenterStreet entrance on the south end of the campus. The attendant will issue you atemporary parking permit and give you directions to parking areas and the NBMGoffices. Address mail to: Director/State Geologist, Nevada Bureau of Mines andGe ology /l78, University of Nevada , Re no, NV 89557-0088. A publication list will besent upon request. 'Formore=iniomration n l h e

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Carlin Trend Exploration History - Discovery of the Carlin Deposit

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Transcript of Carlin Trend Exploration History - Discovery of the Carlin Deposit