Cyanidation Studies at the S. A. Lands Gold Mine

CIM Bulletin, Vol. 70, No. 778, 1977

M. I. Brittan, Gold and Uranium Division, Anglo American Corporation of South Africa Limited, R. J. Inglis and J. H. Schoeman, S.A. Land and Exploration Company Limited, and C. E. Smith, Anglo American Research Laboratories, Anglo American Corporation of South Africa Limited, Johannesburg, Republic of South Africa

A number of plant-scale cyanidation tests were carried out in an attempt to uncover the causes of fluctuations in gold recovery efficiency. Computer analysis of the results verified that the treatment of reclaimed waste rock material along with normal run-of-mine ore was having an adverse effect on metallurgical efficiency. Mineralogical examinations showed that the free gold particles in the dump material were heavily tarnished or coated (predominantly by hydrated iron oxide), accounting for the lower recoveries. The indications were that the effect could be counteracted somewhat by using higher than normal cyanide and lime reagent concentrations and adequate leaching times. Analysis of the results showed further that leach pulp density was an important operating parameter affecting extraction efficiency. A variable activation energy leaching model provided an extremely good characterization of individual batch leach runs.

Keywords: Gold metallurgy, Cyanidation, S. A. Lands Gold Mine, South Africa, Reagents, Computer analysis, Mathematical models, Leaching.