Over the bridge of your choice into the East Bay, are the Black Diamond Mines Regional Preserve in Antioch, and this weekend they are having a special open house with self-guided tours of 1,000 feet of underground restored 1930s-era silica sand mine.
This may not be for the claustrophobic, and definitely not for the youngest – those under age 7 can explore the entry area of the mines, but not take a full tour. The event runs from noon to 4:30 p.m. on March 2.
Originally Native American land, ranching was the main work of the region until the discovery of coal. In the 1860s, coaling mining operations thrived, but soon production costs increased, and California’s economy had shifted toward more industrial. This lead to mining for sand in the area, which was used in glass-making factories, until that ended in 1949. Once mining operations ceased, ranching was king again, using some of the abandoned mining structures as part of water troughs, barns, and more.
