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Hydraulic Mining

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Mining Processes

 Hydraulic mining or hydraulicking is the alluvial mining of gold in deep-set placer deposits using the force of high-pressure water jets to break up the face of a gravel bank or cliff. Hydraulic mining is also treated as a variation of ground sluicing since loosened debris and water gets washed down through a channel or ditch into sluices. Hydraulic mining was first used in the 1880s by miners during the California Gold Rush but was eventually abandoned in North America due in part to the devastating environmental damage it caused. Today, it is still used in some parts of the world in gold mining but the application has also been adapted for use in excavation in building projects, with the sediment being recycled for land reclamation and landscaping.[1]

Contents

[edit] History

[edit] Hushing

The Roman Empire was the first to use an early version of hydraulic mining in the recovery of gold known as "hushing." Hushing involved using big tanks of water built and set up on a hilltop to flush an area with a large concentration of water in order to reveal veins of ore. The method was mostly effective on steep slopes to produce a maximum force of water and was deplored in conjunction with another technique called fire-setting. Used in open-pit mines, fire-setting involved heating up the rock with fire and then dousing it with water. The drastic change in temperature caused the rock to fracture.[2] The Romans were ingenious in the mining of gold and developed sluices and an early version of the Long Tom. They even mined underground and introduced waterwheels to mining.[3] The principle of hushing was then modified and it evolved into hydraulic mining, using narrow hoses and pipes to generate high-pressure jets of water powerful enough to clear away entire hillsides.

[edit] Hydraulic Mining in California

Between 1849 and 1852, tools used in gold mining underwent rapid development, spurred by the needs of the California Gold Rush. Gold mining turned from a primarily individual task using a pan into a widescale commercial operation within a few years. For example, the two-man rocker, then the Long Tom, and finally the sluice box superseded the gold pan rather quickly. The execution of each method depended on large quantities of water and a network of ditches or channels supplying the water from a nearby creek or river. By 1852 ground sluicing was being used to wash larger amounts of overburden and direct payload through sluices. It was from the practice of ground sluicing that hydraulic mining evolved and developed in the mining camps of northern Sierra Nevada during the California Gold Rush. Eventually hoses were used to direct water in ground sluicing operations.[4] Hydraulic mining became the dominant method used in California gold mining and remained so until 1884.

[edit] Developments in Hydraulic Mining

The first application of hydraulic mining took place in 1853 and is credited to Edward E. Mattson, a miner with American Hill in Nevada. The hose Mattson used was made of rawhide and the nozzle was carved out of wood.[5] Hoses proved to be extremely resourceful means of washing away tons of boulders, gravel, and dirt. Their use resulted in saving a lot of labor tied up in digging—in some cases, about two hundred men—with picks and shovels working a bank.[6]

Water was diverted into ditches or wooden flumes placed at a higher elevation and gravity did the rest. Hoses underwent technological developments and improvements. The material of the hose was replaced with canvas and the nozzle was replaced by iron.[7] Companies paid close attention to overall design and hose specification, manufacturing hoses that had more flexibility and a greater range of movement. Some of the product names were the Hoskin’s Dictator and the Hoskin’s Little Giant. The most powerful hydraulic hose developed, however, was the Monitor, made by Craig Co.[8]

[edit] The Monitor

The Monitor was the premiere hose used in hydraulic mining during the California Gold Rush and its power was unprecedented. The Monitor featured a heavy iron pipe that blasted water compressed inside a nozzle with a force of up to 5,000 pounds (2,268 kg).[9] It was likened to a huge cannon that could blow a mountain to smithereens and leave a huge crater. The force of water ejected from the Monitor was also known to be capable of killing a man if struck by it. Some documented accounts recall men being killed by the sheer force of the Monitor’s jet stream as far as 200 feet (61 m) away.[10] Monitors were soon used in mining operations 24 hours a day. At night, mines would be lit up with strong lights or locomotive headlights so work could be carried out around the clock. The need for mass volumes of water in hydraulic mining was also colossal. At one mine called the North Bloomfield Mine, sixty million gallons (227 million L) of water were required for daily operations.[11]

[edit] Hydraulic Mining Becomes Big Business

Hydraulic mining also changed the infrastructure of the mining industry. As the use of hoses spread to subsequent operations on different claims, partnerships were quickly formed. Water supply also emerged as a big business and a number of companies were developed to tap and sell local water supplies and dig larger networks of ditches and canals. Smaller claims run by individual owner-operators soon got overtaken by capital interests and wage labor. Some smaller operations lost their claims because they could not afford their water bills. Even ditch companies felt the effects, with some seeking bankruptcy when competition moved in and offered better prices on water ditch systems.

Hard rock tunnels were also being constructed to carry away the large amounts of washed debris from the mine, caused by hydraulic operations. The debris was unloaded in nearby rivers and ravines. Water needs became so great that hundreds of miles of ditch systems and the construction of mountain reservoirs were needed to keep operations going. Claims were consolidated and stock companies formed to address capital needs. The industry eventually became consolidated into about two-dozen companies controlling the best claims, with hundreds of smaller mines remaining throughout the Sierra Nevada area.[12]

[edit] The Sawyer Injunction

The use of hydraulic mining was cut short in California due to its catastrophic effects on the environment. When the debris was cut away from the mountain and hillsides, it was dumped and washed away in rivers and creeks. By 1891 hydraulic mining in the Sierra Nevada area led to the depositing of about 211 million cubic yards (161 million m3) of debris into the Yuba, American, and Bear rivers alone.[13] This was equal to all the soil excavated in the Panama Canal eight times over.[14] The debris clogged up rivers, buried streams, threatened the livelihood of fish habitats, and spread into riverside farmland, ruining many farms. The impact of hydraulic mining on the environment led to a series of local and federal lawsuits including a debate over its use in the California State Legislature. In 1884 a federal circuit judge by the name of Lorenzo Sawyer issued an injunction against the mining industry in the discharging of its debris. Many hydraulic mining operations shut down afterwards, not only because of the injunction, but also because the cost of hydraulic mining grew to be too high. The industry petered out, with only a few hydraulic mining operations still remaining by the 1960s. On the plus side, hydraulic mining technology was adapted for use in other applications such as irrigation and hydropower.[15]

[edit] Hydraulic Mining in the Yukon

After the end of the Klondike Gold Rush in the Yukon in 1898, mining shifted from a labor-intensive operation to a capital venture. This opened up opportunity in the industry for the mechanization of large-scale hydraulic mining and dredge mining. Hydraulic mining was used to recover greater quantities of gold from the hillsides along rivers. Dredges owned by corporations with rights to an entire creek, known as a concession, eventually replaced hydraulic mining.[16]

[edit] References

  1. What is Hydraulic Mining? WiseGeek. 2008-12-01.
  2. Gold Mining Techniques. Best Hydraulic. 2008-12-01.
  3. [http://www.onlygold.com/TutorialPages/HistoryFS.htm
  4. Hydraulic Gold Mining in California's Sierra Nevada Mountains. Central Pacific Railroad Photographic History Museum. 2008-12-01.
  5. Hydraulic Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  6. Hittell, S. John. Mining in the Pacific States of America. Read Books, 2007, pg. 144- 145.
  7. Hydraulic Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  8. Hydraulic Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  9. Giant Gold Machines - Hydraulic Mining. Oakland Museum of California. 2008-12-01.
  10. Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  11. Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  12. Hydraulic Gold Mining in California's Sierra Nevada Mountains. Central Pacific Railroad Photographic History Museum.
  13. Mining. Sierra Nevada Virtual Museum. 2008-12-01.
  14. Giant Gold Machines - Hydraulic Mining. Oakland Museum of California. 2008-12-01.
  15. Hydraulic Gold Mining in California's Sierra Nevada Mountains. Central Pacific Railroad Photographic History Museum.
  16. Discovered Klondike Gold? Great Unsolved Mysteries in Canadian History. 2008-12-01.