At the start of the Gold Rush, One could simply pick the gold up off the ground. As more and more prospectors came and time went by, other methods had to be used. The first such technique was panning. This method however was too slow and couldn't be used to make to most profit. Miners soon started using 'long-toms' to process larger amounts in faster time. The most complex method used involved diverting water from an entire river and into a sluice alongside it. Then the would dig for gold in the now exposed river bottom. Estimates done by the U.S. Geological Survey say that almost 12 million ounces of gold were collected in the first five years. That amount would be worth around $16 billion Dollars in the US now.
By 1853, hydraulic minig was used in areas with previously high gold returns. This type of mining used high-pressure hoses that were directed at gold-bearing gravel beds. This loosened the gravel and gold alike, which then passed over sluices allowing the gold to settle to the bottom. By the mid-1880's, an estimate of 11 million ounces of gold had been recovered using this method. The current value of which would be approximately 15 Billion dollars. The method, later, spread around the world. Another method involved digging a shaft 20-40 feet deep into the bedrock along the shore or stream. Tunnels were then dug to reach the richest veins of gold. This style was know as 'coyoteing'. The result of these methods was that gravel, silt, heavy metals and other pollutants went into the streams and rivers. Many areas also still have areas of exposed earth and gravel deposits were plant life will not grow.
People still tried to get gold, even after the Gold Rush ended. By the late 1890's, dredging operations were was being used to collect the loose gold that washed down into California's Central Valley and other areas. Approximately 20 million ounces of gold were recovered this way. Today's worth would be around 28 billion dollars. During and after the rush, 'hard-rock' mining was used. This method involved digging or blasting to follow and remove the gold veins. After the gold-bearing rocks had been removed, the rocks were crushed and the gold was seperated by ether using moving water or leeched out by using arsenic or mercury . Hard-rock mining was the single largest source of gold produced during that time.