Malakoff Diggins, California

This site consists of a square-mile mining pit with unusual erosional features, now a State Historic Park, and the restored historic town of North Bloomfield adjacent to it. The Malakoff mine was created mostly in the 1870's using the hydraulic mining technique. Hydraulic mining employed high-pressure water cannons to remove soil and rock surrounding gold deposits. Several water cannons were used here to erode the sedimentary rock, mixing it into a slurry from which gold was extracted. The network of underground drains and tunnels here was extensive. The main drain for the pit was over 7,500 feet long. At least one tunnel is still open and is wide enough to walk through. The sediment from hydraulic mining areas such as Malakoff, which is just one of many sites all over the western slope of the Sierra, choked streams and rivers and deposited an estimated 1.5 billion cubic yards of sediment into San Francisco Bay, where it remains today as a layer of mud around three feet thick. The practice of hydraulic mining was stopped in 1884, due to a lawsuit brought by farmer Edwards Woodruff in 1882 (Woodruff v. North Bloomfield Gravel Mining Company), in response to excessive debris produced by the mining operation. The resulting Sawyer Decision is often cited as the first major environmental law passed in this country. (The lawsuit was also supported by the Southern Pacific Railway Company, which was concerned about damage to its tracks from the drainage and siltation associated with hydraulic mining.)