This historic mercury mine was active from 1910 up to the 1950´s and consisted of several shallow open cuts and 100 feet of subsurface workings. Historic photographs of the mine in operation, indicated several structures were present which may have housed the miners. However, very little evidence of these structures remained prior to site clean up. The mercury retort or furnace structures were removed. One small rock crusher, generator, ore hopper and grizzly (metal grating) were the only mining artifacts left.
Historically, the mercury calcines were dumped into the steep ravine and, over time, a substantial portion of the wastes were washed downstream. The remediation plan entailed excavation, consolidation, and reburial of 3,000 cubic yards of calcines wastes and other mining debris.
In 2001 the calcines were removed from the riparian and adjacent zones and consolidated and capped at a former mining haul road site located on the western side of the mill area. The retort wastes were capped with two-three feet of native (non-mercury ore) soil, seeded with the native plants and then covered with the weed-free rice straw. The excavated calcine pit was recontoured with native soil, reseeded with the same native plants. Five rows of rice bales were staked along slope contours to reduce stormwater runoff. A post-remediation monitoring and sampling program is planned to determine the effectiveness of remediation efforts. Total remediation or cleanup costs for the project were $17,400
Risk: Water quality, Hg contamination
Location: Section 13, T12E, R18S, MDBM, San Benito Co. CA
Field Office : Hollister
Congressional District: 17