10.2 Historical Development In the early days of South African gold mining, the crude bullion produced had to be shipped to London for refining. The concept of a local refinery had been considered for several years before the first positive step was taken in 1909, when the Transvaal Chamber of Mines founded the Witwatersrand Co-operative Smelting Works, to treat the gold and silver bearing by-p...

Tarnishing, corrosion and stress corrosion cracking (SeC) of gold alloys are related phenomena. They present problems when they occur in gold jewellery, dental gold alloys and electronic devices. They are exploited, however, in the depletion gilding and finishing of gold jewellery; and in the extraction, refining and fire assaying of gold. There is still much that is not known about these pheno...