While the origins of hydraulic mining could be traced to ancient Roman technology, it’s popularly recognized use came around in the 1850s with the California Gold Rush. By shooting high pressure jets of water to dislodge and direct earth, hydraulic mining brought new life to the mostly played out placer claims of the California foothills. Yet the reckless leveling of earth propelled miners into a desperate conflict with Sacramento farmers resulting in nationwide regulations.
California Gold Rush
Hydraulic Mining as we know it was first used in 1853 outside of Nevada City, California by Edward Matteson. He used canvas hoses to redirect water and dislodge gravel. As the more easily accessible gold deposits in California were depleted, miners generally had two choices: hard rock mining or hydraulic mining. Hard rock mining followed veins of gold to get at the source. Hydraulic mining took the opposite course: focusing on scale to process enough gravel to extract what small trace amounts of gold still remained in placer deposits. 11 million ounces of gold are estimated to have been extracted via hydraulic mining by the mid-1880s.
The Miner’s Waterfall
Hydraulic mining was a natural progression from ground sluicing. Rather than shoveling gold bearing gravel into the sluices, mining companies could shoot high pressure jets of water to dislodge and direct earth. Pressure was created by tapping water sources at higher elevations. The water would travel through gradually narrowing pipes, building pressure to the point that it erupted with a massive force to scour mountain sides, dislodging plants, gravel, boulders, and gold. The resulting slurry would be run through a sluice to extract the gold. What happened to the runoff was someone else’s problem…until it wasn’t.
The Malakoff Diggins is the largest hydraulic mining site in California. Years of hydraulic mining has left an artificial canyon 7,000 feet long, 3,000 feet wide, and 600 feet deep. Early, small scale placer miners referred to the area as Humbug due to many failed attempts to mine the local rivers. Yet, gold was there. It was not until hydraulic mining that gold could be profitably extracted. At its height, 7 water canons operated in the Malakoff Diggins around the clock. The operation was supported by a population of 2000 in North Bloomfield. By 1880, electric lights were installed and the first long distance telephone line was constructed to service the mine. Everything appeared to be going well. Unlike many other mining endeavors, it wasn’t lack of gold that shut down the North Bloomfield Mining and Gravel Company.
Edwards Woodruff v. North Bloomfield Mining and Gravel Company
While environmental concerns had long swirled around the hydraulic mining technique, it finally came to a head as the runoff silt from mines began effecting farmers in the Sacramento Valley. Millions of tons of earth flowed from the diggings of the California foothills down to the Sacramento Valley. San Francisco Bay was filling with silt at a rate of 1 foot per year. The raised river levels from the deposited silt lead to record flooding, devastating the local farmers. So the farmers took the miners to court.
The case was Edwards Woodruff v. North Bloomfield Mining and Gravel Company. On January 7, 1884, the United States District Court in San Francisco ruled in favor of the Sacramento farmers and banned hydraulic mining. The was the end of the Malakoff Diggins. Today, the remains can be visited at the Malakoff Diggins State Historic Park.
This ruling was amended by the United States Congress with the Camminetti Act in 1893. It allowed small scale hydraulic mining but required a silt retention pond to prevent the damage to rivers and streams. In the past, hydraulic mining was successful because it was cheep. But these new regulations left the practice mostly unprofitable. Today, hydraulic mining is mostly relegated to use in developing countries.