The principal technology is the cyanide process, in which gold is leached from the ore by treatment with a solution of cyanide. The first step is comminution (grinding) to increase surface area and expose the gold to the extracting solution. The extraction is conducted by dump leaching or heap leaching processes. Sodium cyanide is produced on a billion-ton/year scale mainly for this purpose. "Black cyanide", a carbon-contaminated form of calcium cyanide (Ca(CN)₂) is often used because it is cheap. The crude ore is washed with a c. 0.3% solution of cyanide in air, often repeatedly, and the aqueous extract is collected and refined further. Recovery from solution typically involves adsorption on activated carbon, the carbon in pulp process.

Thiosulfate leaching has been proven to be effective on ores with high soluble copper values or ores which experience preg-robbing.

Leaching through bulk leach extractable gold, or BLEG, is also a process that is used to test an area for gold concentrations where gold may not be immediately visible.

Amalgamation with mercury can be used to recover very small gold particles, and mercury is still widely used in small-scale artisanal mining across the world. Mercury forms a mercury-gold amalgam with smaller gold particles, and then the gold is concentrated by boiling away the mercury from the amalgam. This is effective in extracting very small gold particles, but the process is hazardous due to the toxicity of mercury vapour. Large-scale use of mercury stopped in the 1960s. However, mercury is still used in artisanal and small-scale gold mining . One mechanism by which mercury is employed in hydraulic mining is as an "undercurrent", in which the flow of smaller grains is diverted over mercury-coated copper plates. High flow velocities associated with hydraulic mining cause flouring of mercury, the wearing down of mercury particles that contributes to mercury loss into the environment.

The refractory ore treatment processes may be preceded by concentration (usually sulphide flotation). Roasting is used to oxidize both the sulphur and organic carbon at high temperatures using air and/or oxygen. Bio-oxidation involves the use of bacteria that promote oxidation reactions in an aqueous environment. Pressure oxidation is an aqueous process for sulphur removal carried out in a continuous autoclave, operating at high pressures and somewhat elevated temperatures. The Albion process utilises a combination of ultrafine grinding and atmospheric, auto-thermal, oxidative leaching.

Parting is a process by which gold is purified to a commercially-tradeable standard, typically ≥99.5%. Removal of silver is of particular interest since the two metals often co-purify. The standard procedure is based on the Miller process. The separation is achieved by passing chlorine gas into a molten alloy. The technique is practiced on a large scale (e.g. 500 kg). The principle of the method exploits the nobility of gold, such that at high temperatures, gold does not react with chlorine, but virtually all contaminating metals do. Thus, at c. 500 °C, as the chlorine gas is passed through molten mixture (again, mainly gold), a low-density slag forms on top, which can be decanted from the liquid gold. Silver chloride and other precious metals can be recovered from this slag. The slag layer is often diluted with a flux like borax to facilitate the separation.