The Black Diamond Mines Regional Preserve is a 6, 000-acre park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District. The district acquired the property in 1973, the preserve contains relics of 3 mining towns, former coal and sand mines, and offers guided tours of a former sand mine. The 60 miles of trails in the Preserve cross rolling foothill terrain covered with grassland, California oak woodland, California mixed evergreen forest, and chaparral. From 1850 to 1906, the area was known as the Mount Diablo Coalfield, the area includes the remains of twelve coal mines and the sites of three long-gone coal mining towns. The Preserve contains over 200 miles of mine workings, the largest and oldest town, Nortonville, had a peak population of about 1,000. Somersville, Stewartville, West Hartley and Judsonville were located in valleys to the east, the sites of Stewartville and West Hartley are located on private property outside the eastern boundary of the Preserve. The mines were the Empire, Central, Star, Corcoran, Pittsburg, Manhattan, Eureka, Independent, Union, Black Diamond, Mt. Hope, and Cumberland. The coal produced was of a low grade, but for a time in the 19th century, was the readily accessible. Therefore, it was a valuable resource and powering the railroads, ships. The mineral was called black diamond. Coal mining activity ended as better-quality imported coal became affordable and as petroleum emerged as an energy source, after the coal mines closed, the towns were abandoned and the area was used mainly for cattle grazing. Rose Hill Cemetery, the resting place for over 200 residents of the coalfield, is located on a hillside between the Somersville and Nortonville townsites. Many of the burials were for children who died in epidemics of fever, typhoid fever, smallpox. Many of the gravestones have been stolen or destroyed by vandals, the coal mines are closed due to hazards posed by the age of the mines, the gases they produce, and their rock quality. However, a number of mine openings have been turned into public-access openings which allow visitors to look into the mines and, for some, the deepest public-access opening is known as Prospect Tunnel. Visitors can enter 200 feet of this made by miners searching for coal. In the 1920s, a mine producing high-quality silica sandstone was started by owner Marvin Greathouse on a hillside above the Somersville townsite and he sold the product to the Hazel-Atlas Glass Company which operated a plant in Oakland manufacturing glass containers. Hazel-Atlas eventually purchased the mine and operated it until about 1945, another sandstone mine in the Nortonville area produced sand used by the Columbia Steel mill in Pittsburg, California for steel casting
Image: Black Diamond Mines (Antioch, CA)
Historic marker for Mt. Diablo coal field
Inside the Hazel-Atlas Mine at Black Diamond Mines Regional Preserve. Photo by Heather Grimes. September 30, 2012.
Greathouse Portal, Black Diamond Mine Regional Preserve in 2012. Photo by Robin Mayoff.