Primary deposits are usually discovered by coincidence during mining of secondary material. The gold is embedded in rock. The type and the condition of the rock with the gold vein, define the technique to be applied for extraction.
Most common mining techniques on primary deposits are the use of water (in case of decomposed rocks), hydraulic hammers, tractors and explosives.
Another form of exploitation of primary deposits is underground mining. The first step in an underground mine is the opening of a shaft with edge length between one and one and a half meter. The well is dug deeper, until a layer of gravel or auriferous mineralized rock is found. When a deposit of gold is found, the miners try to follow the path of the gravel. To do so they dig a horizontal tunnel, or they use explosives to create chambers along the gold seam. Rollers or mechanical crushers are used to grind the ore into fine sand, which is then treated by mercury or cyanide.