Golden Star group, San Francisco Mining District, Oatman Mining District, Black Mountains, Mohave County, Arizona, USAi

Regional Level Types
Golden Star group	Prospect
San Francisco Mining District	Mining District
Oatman Mining District	Mining District
Black Mountains	Mountain Range
Mohave County	County
Arizona	State
USA	Country

GOLDEN STAR GROUP.

The Golden Star group of mines comprises seven or eight properties, mainly in the prospect stage, situated in the northwest corner of the district about 2 miles northwest of the Moss mine. They extend from the north slope of the Moss Hills northward mostly on open ground to Cottonwood Wash, a distance of about 2 miles.

The camp is located in the northern part of the area at about 2,200 feet elevation, just south of Cottonwood Wash and about 140 feet above it, near the point where the wash passes from open country into a canyon. It is reached by wagon road leading from the Moss mine northward, thence westward down Cottonwood Wash.

The group is owned by the Golden Star Mining and Milling Company, of Pasadena, Cal. The principal openings of the group are on the Golden Star, West Point, American Boy, and Red Bluff claims.

West Point prospect. The West Point prospect is located in the lower west slope of the Moss Hills, on the West Point claim, about half a mile south and 100 feet above the camp, in gray andesite, which here contains considerable breccia. The vein is about 3-| feet in width. It strikes N. 65° W. and dips about 80° NE. It has very much the appearance of a finely sheeted or cleaved dike, subsequently silicified, and is said to contain the highest-grade ore in the camp. The ore is of the quartz-adularia type and its values are in gold. A microscopic section shows it to consist of quartz of variable grain, limonite, and a small amount of adularia.

American Boy mine. The American Boy mine is about a mile south of the camp and 800 feet above it, in the upper north slope of the Moss Hills. It is developed by a 110-foot crosscut tunnel, 200 feet of drift, and a 60-foot shaft sunk to a level with the drift and tunnel.

The country rock is a medium-grained bluish-gray rock, which seems to be an andesite and is locally pyritic. It is cut by a cross sheeting that dips steeply north'and a jointing that trends northnorthwest. An east-west dike of coarse, porphyritic andesite crosses the mouth of the tunnel.

The vein dips steeply to the northeast. It varies from 6 inches to 2 feet in width and contains chiefly impure gray and dark, coarsely crystalline calcite with local bodies of dense greenish quartz about an inch in maximum diameter. It is tightly frozen to both walls. The croppings are silicified country rock and spar, and some of the surface ore is said to have averaged about $100 in gold to the ton.

Golden Star mine. The Golden Star mine is about a mile southeast of the camp, in the lower north slope of the hills, in a gulch that trends to the northwest (PI. XII, A). The country rock is dark gray pyritic andesite, which near by rests upon an older coarsely porphyritic green rock and locally upon the pre-Cambrian pegmatitic granite which here forms the core of the hills. The vein is composed of calcite and quartz, the croppings of which are stained by iron and manganese oxide. It varies from 1 to 14 feet in width, dips 65° to 70° N., has a known extent of about a mile, and is cut by the Meals Ledge on the east. On the hill slope west of the mine the vein is associated with thin, dense green porphyry dikes which parallel it. The mine is developed by a 90-foot shaft. The vein here contains about 3 feet of good-looking calcite or spar, but is of too low grade to be workable.

Red Bluff prospect. The Red Bluff prospect is just north of the camp, on the sides of a long, narrow north-south fault block, where it is crossed by Cotton wood Canyon, whose floor here lies about 140 feet below the neighboring surface. The fault block is about 50 feet wide. It dips 70° E. and extends into the Moss Hills, a distance of more than a mile. The country rock is a gray andesite, which rests upon the pre-Cambrian coarse granite or pegmatite that floors the canyon. These rocks are intruded by a granite porphyry dike 40 feet wide at right angles to the trend of the fault block. After the intrusion of the granite porphyry the dike was cross faulted, and the country rock on the west or foot-wall side of the fault block, including the dike, was carried by lateral throw about 150 feet to the south, to a point about west of the camp. The amount of movement along the fault plane of the fault block has been considerable and has produced from 1 to 14 feet of fault breccia, crushed rock gouge, etc., and here mineralization has taken place.

The best values occur in red, oxidized streaks, principally on the hanging wall, but also on the foot-wall fault plane, and are usually associated with or near by the granite porphyry.

The granite porphyry is a pink or reddish rock with a medium or fine grained groundmass containing phenocrysts of quartz. It contains no ferromagnesian silicates, and under the microscope shows some silicification and secondary growth of adularia.

The property is developed principally by a 45-foot drift and a 50-foot crosscut. The drift, starting near the bottom of the canyon, extends to the south on the hanging-wall fault plane, principally in fault breccia and pre-Cambrian granite, with granite porphyry on its hanging-wall side. From its face the crosscut has been driven through the fault block to the foot wall, without encountering much ore. This deposit appears to warrant further prospecting.