Gold mining - WikipediaIt is impossible to know the exact date that humans first began to mine gold, but some of the .. Larger commercial placer mining operations employ screening plants, . This type of gold mining is characterized by its low cost, as each rock is.gold processing plants and types,Gold cyanidation - WikipediaGold cyanidation is a metallurgical technique for extracting gold from . By 1891, Nebraska pharmacist Gilbert S. Peyton had refined the process at his Mercur Mine in Utah, "the first mining plant in the United.
gold processing plants and types