Chimney Creek Mine (Chimney Prospect), Potosi Mining District, Osgood Mountains, Humboldt County, Nevada, USAi

Regional Level Types
Chimney Creek Mine (Chimney Prospect)	Mine
Potosi Mining District	Mining District
Osgood Mountains	Mountain Range
Humboldt County	County
Nevada	State
USA	Country

Structure:Roberts Mountains Thrust (Below) And Golconda Thrust (Above), Intruded By Mid-Cretaceous Osgood Mt. Granodiorite And Related Trachyandesite Dikes. Chimney Creek Mine Occurs Along A Northeasterly Range Front Lineament That Is Likely An Extension Of The Getchell Fault, The Dominant Structural Feature Of The Getchell, Pinson, And Preble Deposits.

Alteration:Argillization, Carbonate Dissolution, Silicification, Sericite-Pyrite Argillic To Propylitic Alteration. See Geology Comments.

Tectonics:Nevadan And Basin And Range Block Faulting

Commodity:Preliminary metallurgical tests indicate that the ore would be amenable to conventional gold-milling processes with relatively high recoveries. Potential sdg.

Deposit: Additional gold mineralization was encountered in some drill holes outside the main mineralized area, though these holes have not been included in estimating reserves. This record is an updated version including information from w700409 and m242950, which have been deleted. ; info.src : 1 pub lit; 2 unpub rept; 5 pers comm

Deposit type: Carbonate-hosted Au-Ag

Development: Expl.com: single bench; cyanidation; construction; crushing; screening; leach pad construction; rotary drilling. Claims cover 53 square miles. Comprehensive exploration program was begun in 1985, including geological and geophysical surveys and 180 relatively shallo W drill holes on 100-ft centers. Feasibility study scheduled for 1986 completion. Test lot was mined in 1986. Planned production is 11,000 tpd. In 1987, planned production is 150,000 oz Au per year. ; total$: 90 ; econ.com: chimney creek is one of humboldt county's low-cost, high-grade gold producers.

Geology: Alteration comments: argillization, carbonate dissolution, silicification, sericite-pyrite argillic to propylitic alteration. Argillization, carbonate dissolution silicification in etchart limestone. Sericite-pyrite argillic to propylitic alteration of goughs canyon basalt along feeder faults. Argillization has converted illite to sericite, kaolinite, dickite, alunite, and natroalunite. Dissolution and replacement of carbonate beds in etchart limestone centered on feeder faults. Early silicification (termed "bedded jasperoid") is most diagnostic alteration phase present and is invariably gold-bearing. Later silicification is localized along faults that dissect the chimney creek orebody. Geology comments: the chimney creek deposit is sandwiched between the mid-paleozoic roberts mountains thrust and the permo-triassic golconda thrust. Alteration and mineralization were channeled into the thick-bedded lower member of the etchart limestone along high angle feeder zones in the gough's canyon basalt. Mineralizing hydrothermal fluids spread out laterally along bedding to form the conformable orebody, with gold grade decreasing with distance from feeder faults. Gold-bearing bedded jasperoids form tabular bodies from 30-50 m thick extending at least 600 m outward from the center of the orebody.

Rock formation(s):Etchart Limestone;Etchart Limestone;Etchart Limestone;Etchart Limestone;Goughs Canyon Basalt


Ore(s):Alteration And Mineralization Were Channeled Into The Thick Bedded Lower Member Of The Etchart Limestone Along High Angle Fault Feeder Zones. Gold Deposition Is Spatially And Temporally Associated With Carbonate Dissolution And Bedding-Conformable Silicification. 90% Of Ore Is Hosted By Etchart Limestone, 10% By Underlying Goughs Canyon Basalt. The Highest Au-Ag Grades Are Coincident With The Most Severe Carbonate Dissolution Zones In The Etchart Limestone.

Other Databases

Link to USGS MRDS:	10037801
Link to USGS MRDS:	10084981
Link to USGS MRDS:	10047577

Other Regions, Features and Areas containing this locality

References