The ASGM process begins with the excavation of gold-containing ore, which can be accomplished by panning in streams, surface and shallow digging, or by tunneling using shovels, picks, heavy excavation equipment, or dynamite. Ore is then crushed using a large hand-held mortar and pestle or generator-powered grinding machines, or both. Once a fine powder is produced, it is sifted through cloth over a basin. Large pieces trapped in the cloth are re-ground and re-sifted. This fine ore is mixed with water and carefully poured down a carpeted ramp. The carpet traps dense gold-containing particles, and less dense particles are washed down the ramp. The trapped particles are added to a pan with water, and gently centrifuged by hand to further separate the gold from the less dense ore. The gold particles are then mixed in small volumes with several drops of mercury, which forms an amalgam with the gold. Miners heat the amalgam with a blowtorch or small fire, which volatilizes the mercury and leaves behind a piece of concentrated gold. At this stage, the gold is usually sold to dealers, who repeat the mercury amalgamation and volatilization process to further refine the gold.
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