Gold Quarry Mine (Maggie claims; Nevada Bureau of Mines & Geology Sample Site No. 1560; Deep West Ore Body), Maggie Creek Subdistrict, Carlin Trend, Eureka Co., Nevada, USA
|Latitude & Longitude (WGS84):||40° 47' 29'' North , 116° 12' 33'' West|
|Latitude & Longitude (decimal):||40.79139,-116.20917|
|Owned/operated by:||Newmont Mining Corporation|
|Köppen climate type:||BSk : Cold semi-arid (steppe) climate|
A former Au-Ag-As-Sb-Hg-Tl-Ba-Pb-Zn-Cu-Mn-Ni mine located in sec. 35, T34N, R51E, MDM, 7 miles NW of Carlin, on land of mixed ownership (located claim; private lease; private). Discovered in 1925 by A. Berning. Produced from 1936 until 2004. Owned and operated by the Newmont Gold Co. (Newmont Mining Corp.) P.O. Box 979, Carlin, Nevada 89822 (1988). MRDS database stated accuracy for this location is 10 meters.
HISTORY: The first claims were staked in 1925 by A. Berning, who leased the property to Cuba Consolidated Mines Company. In 1936, Cuba Consolidated shipped 60 tons of ore averaging 0.417 ore percent (OPT) Au, 0.882 OPT Ag. Newmont Corp. acquired the property in 1962 and conducted a drilling program in 1963-1964 in the vicinity of what is now the northern limit of Gold Quarry. Drilling was centered SW of the jasperoid outcrop from which the 60 tons of ore were mined. Further drilling until 1970 delineated 340,000 tons/0.12 OPT. The lease agreement was discontinued in 1970 due to low Au prices and discouraging metallurgical tests. The property was acquired by Roy Ash and Charles Thornton for $8,000.00. After XRF-XRD studies of Gold Quarry drill cuttings suggested possible open ends of mineralization, the claims were Reacquired in 1972. After 1979, Exploration drilling continued East of the Maggie Creek ore body and significant Au intercepts were encountered. Between 1979 and 1983, 550 conventional circulation holes were drilled on 100-foot centers to an average depth of 600 feet. Blk metallurgical test samples of mill-grade and leach-grade material were mined in 1982-1983. Pre-mining began in late 1983. The first Au was poured in August 1985 (total $: 300). The development consists of a 40-foot adit, and other scattered open cuts.
The new semi-autogenous mill complex currently (1992) processes more than 28,000 short tons per day. In 1989, the Gold Quarry pit was producing 60% of the total material mined and 62% of the Au recovered by Newmont. A total of 300 hourly and salaried people were employed in the Gold Quarry Mine operations group.
MINERALIZATION: Mineralization is a polymetallic deposit (Deposit model code 172; USGS model code 26a; BC deposit profile E03; Deposit model name: Carbonate-hosted Au-Ag deposit; Mark3 model number: 15), hosted in rocks of the the Vinini Formation (quartzite, siltstone, carbonate and chert) plus jasperoid. At the Gold Quarry deposit, in the central Carlin trend, Heitt (1992) reported K/Ar dates ranging from 28 to 27 Ma from supergene alunite veins that crosscut and postdate gold mineralization. The ore body is tabular.
Au is associated with As, Sb, Hg, & Tl. A subordinate association of Ag, Pb, Zn, Cu, & Ni appears to represent earlier mineralizing events. Au grains range <0.1 to 10.0 microns in size and usually occur associated with microfractures or disseminated in microcrystalline cherty matrix. Au:Ag ratio ranges from about 2:1 in mill-grade ores to 1:3 in leach-grade ores. Local alteration is silicification and clay. Local rocks include platy limestone and limy siltstone, chert at the base.
LOCAL GEOLOGIC STRUCTURES: Geologic structures
include the Roberts Mountains Thrust, Good Hope Fault system, Gold Quarry Fault, Etc. These structures created a pervasive fracture system at Gold Quarry. Isoclinal folding of bedding is common. Fissures, fractures zones, faulting, and folding all controlled ore deposition. The Less fault, a high-angle NE-striking structure was an ore-controlling structure in the original Maggie Creek pit.
The deposit is located at the SE corner of the Carlin Window in the Roberts Mountains thrust. The NW-striking Snowbird anticline and Alta anticline have folded host rocks in the pit area.
GEOLOGY OF THE DEPOSIT: Gold Quarry is one of the largest Au deposits in North America. It is comprised of 2 stacked ore bodies: An upper structural stockwork and a lower, stratabound replacement. Overall strike of the main (upper) ore zone is N45E. It is bounded on the W by the Gold Quarry and on the E by the Grey/Challenger fault systems. Mineralization is continuous over 6,000 feet of strike. Mill-grade ore zones crosscut this trend on a N-S to NW strike. The Deep West ore body is a silica replacement zone at the contact of footwall carbonate rocks and hanging wall siliciclastic rocks. It averages 250 feet in thickness, strikes N20E, dips 30-35SE, and has a known strike length of 2,500 feet. The gold grade is double that of the main (upper) ore zone. The Deep West ore zone is the down-dip extension of the Maggie Creek South ore zone.
Gold is present in a gossan in quartzite and chert. Many of the baryte and base metal deposits in the Maggie Creek subdistrict are associated with the Good Hope Fault system (e.g., the Nevada Star Mine, record #M232284). This fault system also appears to link the Gold Quarry and the Tusc deposits. A sense of movement on the Good Hope Fault system has not been established. North of the intersection of the Gold Quarry and Good Hope faults, an entire ridge of silicified Roberts Mountains Formation marks the margin of the Carlin Window. The jasperoid reportedly carries some Au. Gold Quarry and Maggie Creek mines are unusual in that ore is hosted, at least in part, by Paleozoic rocks of the upper plate of the Roberts Mountains thrust.
WORKINGS DATA: Workings include surface openings comprised of open pits. Historic development consisted of a 40-foot adit and other scattered open cuts. The current (1992) operation consisted of an open pit mine, 2 milling facilities, a leach crushing plant, and 3 leach pads. The dimensions of the ultimate pit will be 1 mile by ¾ mile in size and 1,200 feet in depth. The total material in the ultimate pit is estimated at 576.3 million tons, which reflects a 1.3:1 strip ratio.
PRODUCTION DATA: Early shipped ore averaged 0.417 ounces/ton Au and 0.882 ounces/ton Ag.
Mineral ListMineral list contains entries from the region specified including sub-localities
112 valid minerals. 2 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Early Devonian - Silurian|
393.3 - 443.8 Ma
|Slope Assemblage - Platy limestone, dolomite, and chert|
Age: Paleozoic (393.3 - 443.8 Ma)
Stratigraphic Name: Roberts Mountains Formation; Masket Shale
Description: Platy limestone, dolomite and chert are characteristic of the auriferous Roberts Mountains Formation in Nye, Elko, Eureka, and Lander Counties and of the Masket Shale and Gatecliff Formation in northern Nye County. This unit lies with depositional contact over the Hanson Creek Formation of unit SOc of the Carbonate shelf sequence (unit OCc in southern Nevada), and is also structurally imbricated with Carbonate shelf sequence rocks (OCc) and other Slope and Basin assemblages rocks (units DCs, DOts, MDst) across its area of exposure. In the Carlin area, rocks assigned to the Popovich Formation and the informal Bootstrap Limestone (Berger and Theodore, 2005; Jory, 2002) are also included. In the Monitor Range, the Roberts Mountains, and the Sulphur Spring Range, unit DSt is mapped as stratigraphically overlain by unit DSc. To what extent this “overlying” dolomite is truly a stratigraphic unit as opposed to an alteration product of this unit (Nichols and Silberling, 1977a) is unclear. A stratigraphic contact with unit MDst in the Carlin area is possible based on recent mapping (Berger and Theodore, 2005; Theodore, Moring, and others, 2003).
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.