Gold analyses — myths, frauds and truths

CIM Bulletin, Vol. 82, No. 931, 1989

W.G. Bacon, Bacon, Donaldson & Associates Ltd. G.W. Hawthorn, Gary W. Hawthorn P.Eng., G.W. Poling, Mining and Mineral Process Engineering The University of British Columbia

Unassayable gold and platinum group metals have come into vogue in the 70s and 80s in certain jurisdictions as a means of perpetrating fraud. Usual arguments are that a particular ore is not amenable to "conventional fire assaying". Explanations for unassayable gold usually revolve around: evaporation of micron-size gold; vaporization of organic gold complexes; volatization of gold halides; alloying of gold with PGM's which prevents fusion or alloying which prevents collection. This paper reviews several of the myths and truths of gold and PGM assaying with the knowledge that not a single mine operates in the free world producing gold from unassayable ore.
Keywords: Mineral processing, Gold analyses, Assays