Abstract
The geological and mineralogical characteristics as well as the metallurgical (flotation) response of mineralized footwall to the Brakspruit facies-type of Merensky Reef at the K3 shaft in the vicinity of Karee Mine, at Lonmin PLC, was investigated. The grade in the footwall is above the cut-off grade. The nature of this style of mineralisation is poorly understood, resulting in complete lack of predictive capability when dealing with the processing behaviour of this ore type (i.e. footwall). This project therefore aims to investigate the footwall ore properties (such as mineralogy, mineral liberation upon milling and mineral grain size distribution) that influence the platinum group elements (PGE) as well as nickel, copper and sulphur recoveries and grades. Thereafter it compares such properties to those of the overlying Brakspruit facies-type of Merensky Reef. This study has been accomplished by petrographic examination of the ore types, quantitative and qualitative mineralogical analysis using the Mineral Liberation Analyser (MLA), crushing and milling tests, as well as laboratory scale flotation tests on the ore types.
Two boreholes, RS34 Deflection 5 and Deflection 6 comprising mineralized footwall and the overlying Brakspruit facies-type of Merensky Reef were selected, primarily to investigate the petrographic nature (texture, mineralogy and geology) of the footwall and Brakspruit facies-type of Merensky Reef. This was then followed by underground sampling at the K3 shaft, in the vicinity of the Karee mine, where a total of five channel samples were taken, each comprising 10 cm individual subsamples covering footwall as well as the Brakspruit facies-type of Merensky Reef. The underground channel samples were primarily used for milling and flotation tests work.
Various geological and metallurgical parameters of footwall such as mineralogy, grain size distribution, liberation upon milling, and flotation response, were determined and compared to geological and metallurgical parameters of the overlying Brakspruit facies-type of Merensky Reef. Footwall consists predominantly of plagioclase; whereas, Brakspruit facies-type of Merensky Reef comprises predominantly orthopyroxene. In addition to the above, both ore types contain base metal sulphides...
M.Sc. (Geology)