From around 1852, gold miners diverted water from mountain streams into ditches, wooden flumes and inverted siphons. Pulled by gravity and forced down through heavy iron pipes, these pipes got smaller in diameter as they went down the mountainsides. The mounting pressure meant that water exploded from a nozzle with a force greater than 5,000 pounds per square inch. These powerful high-pressure streams of water ripped through clay, rocks and gravel, blasting away entire mountainsides. The gold-bearing gravels were washed through sluices and the heavy gold settled, and was then recovered. This practice is a fore-runner of todays pressure washers.