Copyright © 2004 by Ana Minerva Bonilla                                            Updated: 7/19/06 13:00

The Weekend Miner

California

Kern County

Big Oscar Antimony Deposit : (35.46.09N by 118.32.48W - #3) (Antimony)

Coordinates are for the main entrance of this underground antimony exploration prospect.     

1962County Report 1,California Division of Mines and Geology - The Deposit is located in Secs. 9 & 16, T. 25, R 32E, M.D.M., in the Greenhorn Summit district, on Cow Creek about 1 mile down the Cow Creek Trail, about 2 miles north of Greenhorn Summit. The ownership was held (in 1962) by the Abaca Mining Company, which held 7 ore veins.

Discovered in 1948, it was explored in 1953-4, but no production resulted.

Country rock is medium-grained Isabella granodiorite, widely distributed in the region, but exposed only in small outcrops in the heavily wooded vicinity of the deposit. Quartz veins, which range in width from 1 inch to 2 feet, trend north. Then they dip nearly vertically, in a zone reported to be 30 to 40 feet wide. Several shear zones strike northeast and dip steeply to the southwest. Stibnite is present in some of the quartz veins, and is sparsely present as a replacement of the gougy altered granodiorite in some of the shear zones. Assays are erratic but antimony averaged 5%, as reported by the owners.

A 28-foot shaft was sunk in 1948 on the southeast bank of Cow Creek in the zone of quartz veins, and a 26-foot shaft was sunk in a stibnite-bearing shear zone in the creek bottom. Early in 1953 a Defense Mineral Exploration Adm. (DMEA) contract for $7,500, 88% of which was paid for by the US Government, was approved. The contract called for the deepening of a 28-foot shaft to 88 feet; a 50-foot drift south on the vein, and a 40-foot crosscut, both on the 70-foot level. By mid-1954 the shaft was enlarged to 4 X 7 feet, deepened to 90 feet, timbered in two compartments down to the 70-foot level where a 13-foot drift was driven south, and a 30-foot crosscut was driven west. Below the 70-foot level, water was an acute problem, and the shaft was not timbered as required. Small amounts of stibnite with pyrite were found as veinlets and joint fillings in granodiorite. In the fall of 1954 the DMEA contract was terminated without a discovery having been certified. The property has been idle since 1954. Water stands in the shaft from 30 to 50 feet below the collar.