page_title: Black Diamond Mines Regional Preserve
section_title: Sandstone mine
hierarchical_section_title: Black Diamond Mines Regional Preserve / History / Sandstone mine
caption_attribution_description: English: Black Diamond Mines This is an image of a place or building that is listed on the National Register of Historic Places in the United States of America. Its reference number is 91001425
context_page_description: 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.
context_section_description: In the 1920s, a mine producing high-quality silica sandstone was started by owner Marvin Greathouse on a hillside above the Somersville townsite. 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. The two companies recovered more than 1.8×10⁶ short tons (1.6×10⁶ long tons) of sand between from the 1920s to the 1940s. The Hazel-Atlas mine is being restored and maintained by park staff and can be visited on guided tours which cover the area's mining history and geology.
  Inside the Greathouse portal, a 950 foot (290 m)-long section of the entrance corridor has been made into a museum. The first section is a series of self-guided exhibits, while the larger second section (which has a separate entrance from the outside), houses a reconstruction of the Hazel-Atlas works as it would have appeared around 1940.
  EBRPD originally repurposed the Hazel-Atlas mine as a museum in the 1970s, but storm damage in 2007 forced closure of this attraction for extensive repairs. It did not reopen for five years.
caption: Inside the Hazel-Atlas Mine at Black Diamond Mines Regional Preserve
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