Generator Hill Deposit, Independence Mountains Mining District, Elko County, Nevada, USAi

Regional Level Types
Generator Hill Deposit	Mine
Independence Mountains Mining District	Mining District
Elko County	County
Nevada	State
USA	Country

Structure: Breccia Zone, Faults, Fractures

Alteration: Silicification, Oxidation Of Sulphides, Bleaching, Argillization, Decalcification

Commodity: Ore contains very lo W to essentially no ag, high in sb, as, hg,and some samples have tl. Ore is carbonaceous and contains some barite.

Deposit: Fracture zone contains crystals, pods, & veinlets in brecciated footwall limestone. Ore also occurs along bedding planes usually within ten feet of the fracture zone. Located near the head of burns creek. Historic sb development consisted of a 29 ft. Shaft, 80ft of underground workings, and an open pit. 20 tons of antimony was produced in1918, 12 1/2 tons in 1945. The sb mine was owned by d. Williams and d. Andrae in 1957. For mine map see lawrence 1963 p.47. ; info.src : 1 pub lit; 2 unpub rept

Deposit type: Carbonate-hosted Au-Ag

Development: In mid-1970's, fmc showed an initial interest in the area due to the occurrence of antimony deposits As cited by lawrence (1963, NBMG bull 61). When gold was discovered by sampling surface exposures and drilling, fmc asked freeport gold co. (no W independence mining co.) to joint venture with them. Construction of mine began in 1980, at a cost of about 105 million dollars. In 1983, the mine and mill together employed about 272 persons. Their claim block includes 374 sections along the crest of the independence range where additional exploratory drilling was ongoing by 5 rigs in 1982. Producing mine since 1981-see production comments.

Geology: Fracture zone 12 to 18 inches wide contain single crystals, pods, & veinlets within the brecciated footwall limestone. Ore also occurs along bedding planes usually within 10 feet of the fracture zone. A sample of stockpiled ore contained 17% stibnite, and .5 oz silver per ton. Upper plate rocks are exposed in several windows. Jasperoids and jasperoid breccias are abundant and important in prospecting. According to company geologists, there is no way to discern a Au-bearing jasperoid from a barren one. The jasperoids above the marlboro and generator pits are anomalous in Au As well As sb and ba. Outcrops of jasperoid contain abundant barite, stibnite and calcite in pods and vugs. Rocks sho W open-space textures with many vugs and crosscutting veinlets of drusy quartz. The e- W trending generator jasperoids sho W multiple brecciation or fracturing and are cut by many quartz veinlets. Barite crystals up to 0.5 in commonly fill Fe-stained quartz-encrusted vugs. The marlboro jasperoids reportedly ran 0.1-0.04 oz/t au. They cover the entire hillside N of the marlboro pit. Jasperoids occur over, under, adjacent to, and far from the orebodies. In the generator pit, the jasperoids are mined.

Rock formation(s): Hanson Creek Formation;Roberts Mountains Formation


Ore(s): Fracture Zones, Bedding Planes

References

Other Databases

Link to USGS MRDS:	10111452