Primary/Primary Gold

(i) Newly mined gold that has been extracted from ore but not yet refined. It also refers to mines where gold is the primary product, as opposed to mines such as porphyry copper deposits, from which gold is also recovered as a by-product. Contrast also with secondary metal and scrap gold.

(ii) Primary deposits of gold are the main auriferous orebodies, which may lie just below the surface or, as in South Africa, several thousand metres deep. They take many forms, from Archaean greenstone and gold-quartz conglomerates to epithermal, porphyry, Carlin-type and volcanic massive sulphide (VMS) deposits. Primary deposits contrast with secondary or placer occurrences, which originate by erosion from primary sources.

There are three main ways in which gold occurs in primary situations: gold in solid solution in which lodes are impregnated with sulphide or arsenic minerals within which, in turn, the gold occurs in minute segregations; gold tellurides in which gold is found in veins in association with tellurium (similar to sulphur). Thirdly, gold amalgams in which gold, silver and mercury form an amalgam (often associated with platinum), with a gold content of about forty per cent. Over ninety per cent of mined gold comes from primary deposits.