Black Diamond Mines Regional Preserve, Antioch, CA

Descriptions from the Web

You do not need to go far to taste the Wild West. Warm up with a gradual climb over the grassy hillside above the old abandoned Black Diamond Mine. Enjoy 2 miles of roller-coaster downhill before cruising up the floor of the lazy canyon. Pass remnants of early mines and ranching along the way. Near from trails.com
Guided tours of the Hazel-Atlas mine take visitors through an old mine used to produce silica sand for glass items. The Greathouse Visitor Center, which contains displays and artifacts from the old mining days, is located in an underground excavated chamber. Also on-site is the Rose Hill Cemetary, from americanheritage.com

The East Bay Regional Park District began acquiring land for Black Diamond Mines Regional Preserve in the early 1970s. Today, most of the mining district is within the Preserve's nearly 6,286 acres. The area is an ideal location for hiking, picnicking and nature study. Naturalists conduct a variety from famplosion.com
Temperatures in the summer can be extreme. The 5,717 acre preserve contains 3 historic coal mining sites, a historic cemetery and approximately 50 scenic trails. Very hilly terrain offers spectacular views of the San Francisco Bay Area. from localhikes.com
Steep fire road, 17.21 miles if you do every trail. open area with some oak trees. Old mines to check out. Not good in the wet, just gooopy. Good for one gearif you don't mind jogging some. from singletracks.com
historic displays, mining history, cemetery from museumsusa.org
Book a guided mine tour. from visitcalifornia.com