From the plaque:
Opened by placer miners after
1852, the gold mines expanded into hard rock quarrying
by 1872. Picacho employed 700 miners at its peak from
1895 to 1900. Mill accidents, low ore quality, and the
loss of cheap river transport with the building of Laguna
Dam led to numerous periods of inactivity. With ores far
from worked out, the Picacho Mines, using modern techniques,
again resumed operations in 1984.
Plaque placed by the State Department of Parks and Recreation in cooperation with Squibob Chapter, E Clampus Vitus and the Imperial Valley Pioneers Historical Society. Dedicated April 20, 1985.