Hydraulic mining was a technique widely employed in the Gold Country through the end of the 19th century.  Its brutal purpose was to rip away the surface “country rock” and dirt to get to the underlying gold bearing ore.  Entire hillsides would be swept away in the search for a few ounces of color.  Tons of debris would be swept into nearby streams and canyons and choke the waterways leading to the agricultural centers of the Sacramento Valley.  And it just kept coming - for months, years.   That yellow ooze from up there, somewhere, in the mountains.  More and more of it.  Relentless.  The rivers were full of goo.  Hundreds of acres of prime farmland slowly covered with a deathly veil of muck.  Orchards died, houses were engulfed, flooding was common, boats could no longer navigate through the debris, businesses were failing, and levees now towered over nearby towns.  It was called the “Slickens” and it just kept coming.  Year after year.  For more than thirty years.  A juggernaut of slime, sand, and sorrow.  The residue of California’s hydraulic mining industry of 1852 to 1884, this situation would lead to one of the most significant federal court decisions concerning environmental protection.  The 1884 court case was Woodruff v. North Bloomfield Gravel Mining Company, (the decision was widely known as the Sawyer decision), and the impact was immediate, profound, and precedent setting -- a grossly polluting industry can be shut down for the public good. 

Hydraulic mining began with a logical answer to a golden question -- How could we get to the gold - quickly and cost-effectively?

Hydraulic mining was a variation on an older technique called ground sluicing where the water delivered to the site would be redirected over a cliff like a demonic waterfall. Hydraulic mining shot the water through a nozzle at high pressure onto the face of the cliff, thereby washing away tons of boulders, gravel, dirt, and ounces of gold.  The first use of this method is credited to Edward Mattison in 1853.  Mattison directed the water through a rawhide hose to a nozzle he carved out of wood.  Later miners upgraded their hoses to metal or the more desirable canvas, and the nozzle soon became iron.  Technological advances made the hose and nozzle connections more flexible and allowed greater movement.  Lavish attention was paid to the design and specifications of the nozzle and companies began producing their competing appliances.  The product names were various -- Hoskin’s Dictator and Hoskin’s Little Giant are examples.  But the name that stuck was the product name of the Craig Company -- the Monitor. 

The Monitors were formidable to say the least.   The Monitor powerfully compressed the water into a nozzle that was anywhere from one inch to eight inches in diameter.  The stream of water that could wash down whole hillsides was impressive to behold.  In his multi-volume 1874 - 1890 classic History of California, the historian Hubert Howe Bancroft stated that an eight-inch Monitor could throw 185,000 cubic feet of water in an hour with a velocity of 150 feet per second.  Other accounts of the force are less technical but just as startling.  One description points out that a strong man could not swing a crowbar through a six-inch Monitor stream, yet another commented on the striking phenomenon of a fifty-pound boulder riding the crest of a jet with the power of a cannonball.  Documented evidence recalls that men were killed 200 feet away by the force of the water.

The Monitors operated twenty-fours a day with the mines illuminated by high-intensity lighting or locomotive headlights.  The amount of water needed was enormous.  Near Nevada City, at the North Bloomfield mine (more commonly called Malakoff Diggins), sixty million gallons of water were used daily.  Thomas Bell, the president of the company, estimated in 1876 that the hydraulic mine would consume 16 billion gallons of water in that year alone.

The debris created was equally enormous.  North Bloomfield, a mine about 1 1/8 mile long and 350 - 550 feet deep excavated 41 million cubic yards of material between 1866 and 1884.  In 1891, a group of government engineers estimated that hydraulic mining had deposited 210,746,100 cubic yards of debris along the basins of three rivers alone -- the Yuba, American, and Bear.  That is enough debris to fill approximately 2500 Arco Arenas to the brim.

Images:

Monitor Ad. Jpg = An ad for a hydraulic monitor produced by a Nevada City company in the 1870s.
Credit:  Nevada County Historical Society
Hydraulic Monitors 1870s. Jpg =  Hydraulic monitors in action in the 1870s  - Credit:  Nevada County Historical Society
Malakoff Diggins today . jpg =  Malakoff Diggins today - Credit:  Gary Noy