A stamp mill is a large mechanical device used to crush ore and extract the desired metals from the host material. It uses heavy steel stamps to crush and break apart material, releasing the valuable gold from worthless rock, allowing for the extraction of gold for further refining.
CALIFORNIA MINES. The California Gold Rush (1848–1855) began on January 24, 1848, when gold was discovered by James W. Marshall at Sutter's Mill, in Coloma, California. News of the discovery soon spread, resulting in some 300,000 men, women, and children coming to California from the rest of the United States and abroad.