Bandarita Mine (Bandaritta Mine; Eclipse Mine; Goodwin Mine; Bandarita Nos. 1 & 2 claims; Little Fort Knox claim; Fort Knox No. 2 claim; Kinsley Nos. 1; 2 & 3 claims), Texas Hill, Kinsley Mining District, East Belt, Mariposa County, California, USAi

Regional Level Types
Bandarita Mine (Bandaritta Mine; Eclipse Mine; Goodwin Mine; Bandarita Nos. 1 & 2 claims; Little Fort Knox claim; Fort Knox No. 2 claim; Kinsley Nos. 1; 2 & 3 claims)	Mine
Texas Hill	Hill
Kinsley Mining District	Mining District
East Belt	- not defined -
Mariposa County	County
California	State
USA	Country

A former Au-Ag-Cu-Pb-Sb mine located in the center NW¼ (estmated) sec. 7, T3S, R18E, MDM, 1.4 km (4,400 feet) W of Texas Hill (coordinates of record). Property consisted of 7 claims, 4 patented and 3 (un ?) patented. Discovered in 1856. Owned by the Bandarita Consolidated Gold Mining Company. Operated during the periods 1856-1889 and 1937 to 1940. Operated by W. Lee Brown (C/O W. J. Beatty) and Nelson Leoni (C/O Dolores Pharmacy). MRDS database stated accuracy for this location is 100 meters.

Opened in 1856, this mine was worked almost continuously until 1887 and then sporadically afterward. Its most productive period was 1881-1887. It was last known to be operated from 1937 to 1943.

Mineralization is a vein deposit (Deposit model code 273; USGS model code 36a; Deposit model name: Low-sulfide Au-quartz vein; Mark3 model number 27), hosted in Mesozoic-Paleozoic slate and quartz-biotite hornfels, plus Mesozoic granodiorite. The ore body is generally a pinch & swell form with a strike of N84W and a dip of 47S at a thickness of 3.05 meters.

The deposit at the Bandarita Mine consists of a typical gold- and sulfide-bearing hydrothermal quartz vein within metamorphic wall rock. Granodiorite is present as four individual north-trending dikes that intersect the vein at approximately right angles with throws from 1 to 42 feet. The vein ranges in thickness from 2 to 10 feet. Gold is present both in native form and in sulfides; the gold content was reportedly roughly proportional to the quantity of tetrahedrite present. Thompson (1934) concluded that the ore is present on fault planes along which much movement has taken place. Here, the quartz and slate have been crushed to a gouge.

Local alteration was not reported except for vague references by Thompson (1934) to alteration of the dikes. Associated rock is Late Permian diorite. Local rocks include Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada).

Regional geologic structures include the Sonora Fault.

LOCAL GEOLOGY: The Bandarita Mine is situated in the East Belt of gold mineralization of the Sierra Nevada. The deposit consists of a main gold-bearing quartz vein in slate that is part of the Paleozoic-Mesozoic Calaveras Complex. Regionally, this complex also includes phyllite, metachert, schist, metavolcanic rock, and metacarbonate rock. Other reported rocks associated with the deposit include quartz-biotite hornfels and granodiorite. The granodiorite is present as four individual north-trending dikes that intersect the vein at approximately right angles. Thompson (1934) observed that some of the dikes were altered and leached. The vein strikes N84W and dips 47SW. Its width varies from 2 to 10 feet. Ore consists of quartz with native gold, pyrite, galena, sphalerite, arsenopyrite, and tetrahedrite. The best ore contained considerable tetrahedrite. Thompson (1934) concluded that this ore formed on fault planes that exhibited much movement, which produced a quartz-slate gouge in places. He reported the presence of native gold in the gouge as well as in some of the altered dikes.

Workings include underground openings with an overall depth of 259.08 meters comprised of a 1,364 foot crosscut adit which intersects the vein about 850 feet vertially from the surface, 6 adits driven along strike of the vein, the longest of which is 800 feet, and which taps 3 ore shoots. The crosscut adits tap the vein 1,200 feet along the length.

Workings at this mine consist of adits, crosscuts, drifts, and stopes, some of which are daylighted. Stoping along three ore shoots in one adit ranged from 75 to 650 feet to the surface. Thompson (1934) estimated at least 5,000 feet of workings.

Production data are found in: Bowen and Gray (1957).

During the last period of activity, from 1937 to 1940, approximately $40,000 in Au and Ag was obtained from 7,362 tons of ore. The grade of the ore was lower than that of ore milled in the period 1856 - 1889, when most of the total production of $1,520,000 (period values) of ore was mined. Cu production was 0 - 100,000 pounds.

This mine's most productive period was 1881-1887. It was last known to be operated from 1937 to 1943. when $40,000 (period values) in Au and Ag were obtained from 7,362 tons of ore mined from the Goodwin ore shoot. Amalgamation processes were used at this mine.

Clark (1970) reported a production value of $1.52 million for this mine. In 1940, it was reported that there were still 275,000 tons of gob remaining in the old stopes.

Commodity Information: the Goodwin ore shoot reportedly averaged 0.57 ounces of Au per ton. Bowen and Gray (1957) reported that in 1874 a single mill cleanup yielded 25 pounds of gold from 100 tons of ore. Ore that averaged $25/ton was obtained from at least one location in the main crosscut working.

Other Databases

Link to USGS MRDS:	10031076

Other Regions, Features and Areas containing this locality

References