Gold mining consists of the processes and techniques employed in the removal of gold from the ground. There are several techniques by which gold may be extracted from earth and rock:

Gold panning

Gold panning is comprised of a manual gravimetric technique of sorting by which wide, shallow pans are filled with sand and fine gravel that is thought to contain gold, and shaken with a quantity of water to sort the gold from the rock and other undesirable material on the basis of its density. The gravel is typically removed from streambeds, often at a bend in the streambed, where its greater weight can cause gold to settle out of the streamflow. Concentrations of gold found in streams or dry streambeds are called placer deposits.

Hydraulic mining

Hydraulic mining is employed in areas where large amounts of loose gravel and sand or soil are poorly consolidated, and may be washed away with a heavy stream of water. Water cannons are sometimes used to strip away entire hillsides of loose material, which are then run through a sluice. Being denser, gold becomes concentrated in the sluice as it does not move as readily as other sediment, and may be collected. This technique tends to be highly detrimental to the landscape, and can cause siltification in streams below the mining site, as well as erosion damage at the site itself.

Hard rock mining

Hard rock mining is most consistent with the popular conception of removing rock from the ground, in which miners tunnel and blast into rock, seeking hydrothermal deposits of gold. Veins of gold ore are often found several inches or feet wide in certain rock formations, where the minerals may be removed, collected, and treated to process the gold and other valuable metals (such as silver) from them. This technique is possibly the most energy-intensive, but the most profitable way to harvest significant quantities of the metal.

Cyanide process

Cyanide process extraction of gold may be used in areas where gold-bearing rocks or finer material is found at the surface. Sodium cyanide solution is allowed to leach through a pile of finely-ground rock that has proven to contain gold and silver, and is then collected as gold cyanide and silver cyanide solution. Zinc is added to the solution, precipitating out zinc, silver and gold metals. The zinc is removed with sulphuric acid, leaving a silver and gold amalgam that may be further processed into the individual metals.

The cyanide technique is very simple and straightforward to apply, and popular in areas where mine tailings may contain surprisingly large quantities of valuable metals despite already having been processed, even with previous treatments with cyanide. There can be significant environmental damage caused by the use of this technique (see also: Summitville mine), in addition to the high toxicity presented by the cyanide itself.