Leona Heights Sulfur Mine - Oakland

Leona Heights Sulfur Mine
photo CC SA-BY-NC Our Oakland

The Leona Heights Sulfur Mine was a mine in the Oakland hills that was active from c.1900 to c.1934. ^2,4 In February, 2014, it was announced the owner would be paying for cleanup and encapsulation to help prevent runoff of acid and metals into Leona Creek. ³

The mine was one of several that extracted pyrite from this part of the Oakland Hills. The mineral was processed into sulfuric acid, a basic industrial chemical, by the Stauffer Chemical Company, first at a plant near the Melrose station and later in Stege (now part of Richmond). ⁴

While it isn't clear from the photos, this was a mine with tunnels, not a surface mine. Although the entrance was blocked off for many years, mineral specimens could still be collected there. The recent mitigation measures, however, have permanently covered up the attractive nuisance.

As part of the clean-up the San Francisco Bay Regional Water Quality Control Board prepared a fact sheet describing the site, its history and plans for restoration.⁵

Today

The water flowing from the mine is acidic and full of metals and flows into Leona Creek. The property has been privately owned since 2001, but the contamination from the mining means that mitigation work needs to be done before it could be developed; ¹ the 2014 SFGate article says it can never be developed. ³

It was apparently a popular place for young people to explore and subsequently need rescuing from after being overcome by fumes. A fence was built in 2003 separating it from nearby public land.

You can watch a video of the clean-up's progress on Vimeo (as of March 2015).