Gold From Panning to High-Tech Mining

摘要

Carpenter and wheelwright James Wilson Marshall was just trying to build a sawmill on a California river, not to start a gold rush. But what he found in the tailrace on January 24,1848, forever changed both California and America itself: "My eye was caught by something shining at the bottom of the ditch.... I reached my hand down and picked it up; it made my heart thump, for I was certain it was gold. The piece was about half the size and shape of a pea. Then I saw another...." Since that first strike, prospectors have continued to scour the West for gold. The scale of their quest and its methodology have changed, in some cases only a little, in others beyond recognition. The forty-niners used simple methods to recover lumps and chunks of gold from streambeds or high-quality veins in the rock. Serious gold miners today employ sophisticated chemical techniques and equipment, including specialized metal detectors, to recover microscopic quantities of gold from low-quality deposits.