Black Diamond Regional Preserve

Hazel Atlas Mine Open House When:    Sat, November 21, 12:00pm – 4:30pm Where:  Black Diamond Mines Regional Preserve - 5175 Somersville Rd., Antioch, CA  94509  -  37.955373N 121.863737W (map) Description: Hazel Atlas Mine Free self-guided tours will let you explore nearly 1,000 feet of cool underground workings in this restored 1930s-era silica sand mine. […]