Rawhide Deposit, Rawhide Mining District, Mineral County, Nevada, USAi

Regional Level Types
Rawhide Deposit	Deposit
Rawhide Mining District	Mining District
Mineral County	County
Nevada	State
USA	Country

Structure: Walker Lane And Basin And Range. Large Caldera System Along The Ne Marn Of The Nw Trending Walker Lane Structural Zone. The Miocene Rawhide Volcanic Center Is 6.5 By 12km (4 X 7.5 Mi.) In Area. See Comments

Alteration: See Comments

Tectonics: Continental Magmatic Arc

Commodity: Au occurs As electrum in both oxide and sulfide ores; the electrum is dominantly Au in oxide ore but contains significant Ag in sulfide ore. In oxide ore, Ag occurs primarily As embolite and lesser cerargyrite. In sulfide ore, Ag occurs As the selenides, sulfides and sulfosalts listed above. Ag:au averages 10:1 in both oxide and sulfide zones and generally increases As Au grade decreases with distance from ore. Ag:au ratios As high As 400:1 are known along the base of oxidation and in strongly argillized zones.

Deposit: Quartz veins and lodes in kaolinized rhyolite. Disseminated and stockwork ore (veinlets that appear to follow incipient fissures), As well As sporadic ore bodies associated with abundant breccia, phreatomagmatic and phreatic, with strong silicification bordered by argillic zone. Shallow hot spring environment with abundant hydrofracturing. Oxidized zone up to a few hundred feet deep in vent areas is underlain by a sulfide zone. The chief ore minerals in the oxidized zone are cerargyrite, pyrite, native silver, native gold, and electrum. In sulfide zones - argentite, proustite, pyargyrite, pyrite, gold and electrum. The gangue minerals resulting from hydrothermal replacement are adularia, jarosite, kaolin, pyrite, pyrrhotite, quartz, and calcite. Some Au and Ag recovered by dry wash placer method south and southwest of rawhide. The main belt of mineralization occurs along balloon, murray and grutt hills in this zone, bodies of good grade milling ore are 5 to 30 feet wide. Some Au and Ag recovered by dry wash placer method south and southwest of rawhide. The main belt of mineralization occurs along balloon, murray and grutt hills. In this zone bodies of good grade milling ore are 5 to 30 feet wide. Sporadic ore bodies are associated with brecciation of the rock. Particularly in grutt and murray hill many of the veins trend north to ne. All expt 2 of the veins dip steeply west. Bulk mineable ore occurs primarily in intensely fractured andesite along the hanging wall of the rhyolite intrusion and is characterized by abundant, closely spaced, sheeted to stockwork quartz-adularia veins. Ore also occurs in zones of primary permeability in porous lithic tuffs and volcaniclastic sediments, where it is finely disseminated and is accompanied by pervasive silicification and adularization with minor or no associated veins. Several separate pod-like ore zones occur within a nw-trending area 2440 m long and 400 m wide. Individual ore zones are irregular in geometry but typically are elongate to the n W with local ne-trending apophyses. Mineralized veins strike N to ne, an orientation transverse to the overall trend of the orebodies. Properties in the vicinity of town of rawhide include: morning star, rawhide victor, seminole-regent, mascot, bullskin mountain 1, silver zone, bethania, black eagle, poor boy, wash vein, gold reef, royal, flynn, and nevada new mines. Two mills erected in district in 1909 called the tadmor and cannon ball mills, and operated only a short time. The largest holdings in the district were owned by the scheeline estate (17 1/2 patented claims), and the grutt brothers (19 claims). ; info.src : 1 pub lit; 2 unpub rept

Deposit type: Epithermal vein, Comstock

Development: Drilling numerous holes and making metallurgical tests. Mine construction was initiated in august 1989 and gold production began in april 1990, beginning with the crazy hill deposit. This deposit will probably be mined out by the fall of 1991. Mining of murray hill deposit, next in line, going n W from the crazy hill deposit will commence summer 1991 As well As further exploration drilling. Current exploration target is hooligan hill. A 42,500 ft. Drilling program is planned for 1991. ; total$: 22.5 ; econ.com: est. Cash costs $200 to $225 per oz of Au including silver credits. Production began april 1990 and by year end, 39,000 oz of Au and 170,000 of Ag produced. Yearly production is projected at 81,000 oz of Au and 377,000 oz of Ag for the first five years. Expected 15 year mine life. ( NBMG spec. Pub. Mi 1990 p.16.) expl.com: gold was discovered at rawhide in 1906. Most of the 50,000 oz Au and 750,000 oz Ag produced in the regent district during the period 1907-1920 came from rawhide. Production from leasing operations. George graham rice promoted the rawhide queen m. Co., the rawhide coalition m. Co., and the black eagle m. And m. Co. N 1912 the nevada new mines co. Was incorporated and and took over the george graham rice promotions. Mining in the district has been essentially inactive since minor placer operations were conducted in the 1930's. Over the past several decades numerous mining companies have investigated the potential for bulk-mineable precious metals ore at rawhide. The most notable effort occurred from 1969 to 1971, when a homestake-getty joint venture drilled 58 holes that partially delineated the ore zones of current interest. In 1982 a kennecott subsidiary began work on the property. A joint venture between plexus and kiewit and kennecott worked on the property 1982-1985

Geology: The rawhide district is structurally complex and contains nw, ne, and ns trending fault sets that all sho W pre-syn and post ore deposition movement. Formations in area are rhyolite, dacite, and andesite. Mineralization is mainly in kaolinized rhyolite. Placer deposits overlie the rhyolite in the valleys east and west of balloon and murray hills and continue for 5 1/2 les to alkali flats. The crazy hill deposit is hosted in tuffaceous epiclastic sedimentary, and igneous volcanic rocks that are intruded by a post mineralization rhyolite plug. Alunite is said to occur in thin veins associated with gold ores in altered volcanic rocks. Volcanic rocks consist of vent breccia, flows, plugs, and pyroclastics. Tert approx. 15.5 ma, k-ar ages.

Rock formation(s): Pre-Esmeralda Volcanic Rocks


Ore(s): Fissures. Caldera Along Intersection Between Walker Lane Structural Zone And Ne-Trending Basin And Range Faults

References

Other Databases

Link to USGS MRDS:	10072140
Link to USGS MRDS:	10310397