Into the Breach Craft Unseen

COAL AND SAND: Black Diamond and Hazel-Atlas Mine, Antioch, CA

Photos: Sue Kelso, Alix Hartmann,

Cartographer's note: I was unaware of this mining region until working on this project, though now I want to visit. However, when I mentioned my map project to a friend, they recalled stumbling across this site on a hike and told me that "they mined sand and made Mason jars, and you can take a tour." The Black Diamond coal mine was low-quality and closed quickly but it became a very productive high-quality sand mine. The sand mine tour has been recently joined by a "coal mine experience" which is billed as an immersive tour. This struck me as a little macabre considering the deaths that happened on the site.

"Underground mine areas, which contain dangerous holes and piles of waste rock, are not readily converted to any other use, but fortunately most will be in mountainous areas containing land of minimal value. Locally, a few tunnels are now being used for bombproof storage of valuable records, for raising mushrooms, for aging wine, or as low-yield water tunnels to supply a ranch or two. Nevertheless, the need for abandoned mines for these purposes is limited. For safety most open mines can be sealed at the portal or shaft collar when no longer in use."1

"Four teen-age boys who went on a lark exploring an abandoned coal mine were found dead a mile underground Thursday, apparently overcome by methane gas. The victims were identified as Joel Faulkner, 17, of Antioch, and his brother, Del, 16, and their cousins, Gary Faulkner, 18, and Greg Faulkner, 16, both of Willits, Calif."2

"California is known for gold mining, but the Golden State also has a rich history in sand mining. 'The sand mined here is not your typical sand. Naturalist Kate Collins describes it as 'high-quality sand.'...'The mine has lots of silica sand and it was used to make glass [for things like] shot glasses, beer bottles mason jars salt and pepper shakers,' Collins said. In the 1860’s, low-quality coal was mined in this area. In the 1920’s, the Hazel-Atlas glass factory in Oakland took over and started mining for sand. 'We understand they took out 1.8 million tons of silica sand out of the mine,' Collins said."3

1 Bailey, Edgar H. and Deborah R. Harden. "Map Showing Mineral Resources of the San Francisco San Francisco Bay Region, California - Present Available and Planning for the Future." Miscellaneous Investigations Series, United States Geological Survey, 1975.
2 UPI. “Teen-Agers Die in Abandoned Mine.” Accessed February 28, 2022.
3 “California’s ‘Sandy Past’ Preserved in Antioch,” August 4, 2018.