The Discovery Dondero Mine was submitted by Sean Berry-Kelly who also took the photos. Sean writes;
“This is a now an abandoned mine, down a 2 mile access road off of Yankee hill road, in Columbia, CA. The mine is flooded about 100 feet in, but there are plenty of stopes and drifts. A cabin, outhouse and big metal ore bin are in the area. There isn’t any vehicle traffic after a mile down the access road, due to a wash out.”
Interestingly enough the mine does not show up on any USGS Historic Topo maps despite being mentioned in dozens of mining journals and newspapers from the late 1800’s to the early 1900’s.