Yuba Mine

The Yuba mine is 2 miles west of Greaterville, on the north side of the upper end of Hughes Gulch, at an elevation of 5,850 feet. It was located in 1874, and from it, in the eighties, were shipped some surface ores that are said to have averaged $1 a pound in gold and silver. The total production is several thousand dollars. The property contains three quartz veins, dipping about 55° S., in course sheared granite. The south vein is about 3 feet wide, the middle one about 2½ feet, and the north one of less width. In the longitude of the mine the veins are about parallel and 100 feet apart but at 700 feet they unite into one ledge. The mine is on the southern or main vein, no work other than stripping having been done on the other two. It is opened mainly by four inclined shafts sunk on the vein, the deepest of whichis said to be about 100 feet. Water stands within 15 feet of the surface. The vein is composed of white “bull” quartz, with a little barite and calcite in places. It is banded and shows comb structure, but these feeatures are locally destroyed by postvein movement.

The croppings consist principally of white quartz sparingly spotted with copper carbonates and bunches of black-coated galena. The rich oxidized ores gave out at a depth of 20 feet, but between that limit and the 50 foot level the ore, although spotted, is said to have averaged about $10 in gold and silver to the ton, the gold ad silver being contained galena and chalcopyrite and a few small masses of argentite².

Mining District and Mines

Greaterville District

Location

19S 15E SW¼ 23⁵

-110.78151, 31.76152 (WGS84), elevation 1,783m⁴

Mineral Products

Pb, Zn, Ag, Cu, Au⁵

Ag, Au, Pb, Cu, Zn⁴

Geology

Quartz - calcite - barite veins, banded and with comb texture, containing partially oxidized galena, sphalerite, and chalcopyrite and small pockets of argentite in sheared Precambian granodiorite along a strong fault zone⁵.

Type of Operation and Production

Incline shaft. Worked in 1880s, producing 50 or more tons of high grade Pb - Ag - Au ore.⁵

References

1. Mineral Appraisal of Coronado National Forest, Part 12, Santa Rita Mountains Unit, MLA11-94 (1994). SR 591-609
   http://repository.azgs.az.gov/sites/default/files/dlio/files/nid1813/usbm_mla_011-94.pdf
2. Mining in the Santa Rita and Patagonia Mountains of Arizona, U.S. Department of Interior, 1915. Republished 2014 by Kerby Jackson.
3. mindat.org
4. USGS Mineral Resources Data System - possibly using NAD72 (https://mrdata.usgs.gov/mrds/map-commodity.html#home)
5. Index of Mining Properties in Pima County by Stanton B. Keith, bulletin 189, Arizona Geological Survey, 1974