| This study was initially undertaken to determine the gold deportment in the biooxidation feed, product and product cyanided residue from the Harbour Lights Mine (Western Australia), using microbeam techniques, such as SIMS, TOF-LIMS and EPMA, and optical microscopy.; Approximately 99%, 100% and 94% of the gold assays in the Harbour Lights BIOX{dollar}sp{lcub}circler 1{rcub}{dollar} feed, product and product cyanided residue were accounted for in the gold deportment study.; The results of the batch stirred tank bioreactor study, the shakeflask suspension study and the gold characterization indicate that during biooxidation, enclosed visible and 'invisible' gold is rendered cyanidable by the direct action of Thiobacillus ferrooxidans as well as indirect chemical leaching and possibly galvanic interaction. Visible gold which is enclosed in sulphide minerals is liberated as the host mineral is dissolved chemically, by the microbial generation of ferric sulphate, and directly as areas of arsenic and gold enrichment in pyrite and arsenopyrite create dislocations and weaknesses in the crystal lattice which are preferred sites for bacterial attachment. ftn{dollar}sp1{dollar}Registered trademark of Genmin, General Mining, Metals and Minerals Limited. |
