Black Pearl Mine (Black Pearl group of claims; Camp Wood Tungsten Mine), Loco Gulch, Eureka District, Yavapai Co., Arizona, USA
|Latitude & Longitude (WGS84):||34° 41' 14'' North , 113° 2' 4'' West|
|Latitude & Longitude (decimal):||34.68722,-113.03444|
|Köppen climate type:||BSk : Cold semi-arid (steppe) climate|
A former underground W-Bi-Au-Ag-Mo-Cu-Be-Fluorspar-Quartz mine on 11 patented and 5 unpatented claims in secs. 7, 8 & 18, T.15N., R.7W. & secs. 12 & 13, T.15N., R.8W., approximately 600 feet East of Boulder Creek on the South side of Loco Gulch, 15 miles SW of Camp Wood. Discovered in 1914 by Mr. Wm. Conners, then owned by John Lawler & Homer R. Wood. Produced 1915-1935 & 1951-1956.
Mineralization is a vein deposit with tabular ore bodies en echelon. Dark gray hornblende granite is invaded by pegmatites and crops out beneath Tertiary lava flows. Ore control was faulting. Alteration was oxidation to at least 40 feet below the outcrop.
The principal vein strikes S.74ºE. and dips steeply SW. It is a quartz body 6,000 feet long, 3 feet wide, and 250 feet deep, in granite. Average width of the vein exposed is 4.2 feet. The wall rock is intensely altered to sericite. Gangue is coarsely crystalline grayish-white quartz.
Workings include stopes opened from short adits and shallow shafts with maximum depth of 70 feet below the outcrop. Longest adit is 1,565 feet (Veta adit), with 5 raises to surface, a 155 foot shaft with 700 feet of drifting and 3 stopes. Production was 62,100 pounds of average 70.0% WO3 (1915-1935).
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
15 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.
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1400 - 1600 Ma
|Middle Proterozoic granitic rocks|
Age: Calymmian (1400 - 1600 Ma)
Description: Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)
Comments: ~ 1.4 Ga
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.