Black Diamond Mines Regional Preserve

In 1859 William C. Israel discovered a coal deposit while clearing out spring on his land at Horse Haven Valley, six miles south of Antioch. Indeed, his initial attempt to mine the coal was not financially successful but soon other coal deposits were discovered nearby and mining operations grew rapidly. Then, the area became known as Mount Diablo Coalfield, the largest in California, producing more than 400 million short tons (357 million long tons) of coal during this time.

Rose Hill Cemetery :

Although, little remains of the coal mining communities, a historic cemetery serves as a monument to the lives of the former residents. Therefore, buried here are children who died in epidemics, women who died in childbirth, and men who died in mining disasters and of other things. While over 10 nationalities resided in the mining area, Rose Hill Cemetery was a Protestant burial ground, and many of the people buried here were Welsh.

Sandstone mine :

In the 1920s, a mine producing high-quality silica sandstone was started by owner Marvin Greathouse on a hillside above the Somersville townsite. Indeed, he sold the product to the Hazel-Atlas Glass Company which operated a plant in Oakland manufacturing glass containers. Then, Hazel-Atlas purchased the mine and operated it until about 1945. Moreover, another sandstone mine in the Nortonville area produced sand used by the Columbia Steel mill in Pittsburg, California for steel casting. Furthermore, the two companies recovered more than 1.8×10⁶ short tons (1.6×10⁶ long tons) of sand between the 1920s to the 1940s. Thus, the Hazel-Atlas mine is being restored and maintained by park staff and can be visited on guided tours that cover the area’s mining history and geology.