One of the greatest and richest underground placer mines of California was the Hidden Treasure Mine of Placer County. This was a drift mine, dating back to 1875. It was an Eocene buried river channel of all white quartz gravel, dating back over 70 million years ago. This ancient river was over 600 feet wide and was buried by volcanic mud flows and remained untouched until Michael Power located it and began a historic and successful effort to mine this channel for over 40 years. It took two town sites to complete the mining activity, and, according to records, the channel still has a significant amount of unworked gravels-but that's getting ahead of the story.
展开▼
