Location and History
The Pinacate district is in western Riverside County in the hills between Perris and Lake Elsinore. The area was placer-mined in the 1850s. The Good Hope vein was discovered in 1874, and there was considerable mining activity that lasted until about 1903. Some work was done in the district again in the 1930s, and there has been minor prospecting since.
The area is underlain by shales, slates, phyllites, and quartzites of the Santa Ana Formation (Triassic) and quartz diorite and granodiorite. Quartz latite lies to the west. The ore deposits consist of zones of quartz veins and seams with kaolin and gouge, which contain native gold and varying amounts of sulfides. The sulfide content increases at depth. The ore contains 1/2 to one ounce of gold per ton. The Good Hope vein was mined to a depth of 575 feet.
Argonaut, Brady, Colton, Good Hope $1 million to $2 million, Hoag $140,000, Lake View, Lucky Strike, Musick, Rosalia, Santa Fe, Santa Rosa, Shay, Victor.
Dudley, P. H., 1935, Geology of a portion of the Perris block, southern California: California Div. Mines Rept. 31, pp. 4B7-515.
Engel, Rene, 1959, Geology and mineral deposits of the Lake Elsinore quadrangle: California Div. Mines Bull. 146, 154 pp.
Merrill, F. J. H., 1919, Riverside County, gold: California Min. Bur. Rept. 15, pp. 527-535.
Storms, W. H., 1893, Pinacate district: California Min. Bur. Rept. 11, pp. 384-385.
Tucker, W. B., and Sampson, R. J., 1945, Riverside County, gold: California Div. Mines Rept. 41, pp. 127-144.