THE POTENTIAL OF MINING SLAG AS A SUBSTRATE FOR MICROBIAL-GROWTH AND THE MICROBIOLOGICAL ANALYSIS OF SLAG AND SLAG SEEPAGE

The potential of a Cu/Ni mining slag to act as a substrate for the gro wth of the bacteria Thiobacillus ferrooxidans, Thiobacillus thiooxidan ts, and Thiobacillus thioparus was examined. As well, slag and slag se epage samples were screened for the presence of the Thiobacillus speci es. For the 28 samples employed in the environmental recovery studies, T. ferrooxidans was recovered in 25 samples, T. thiooxidans in 19 sam ples, and T. thioparus in 27 samples. For T. ferrooxidans, the develop ment of a colour change in the medium corresponded with the presence o f motile bacilli as detected microscopically. For T. thiooxidans and T . thioparus, a decrease in culture pH of greater than 0.2 units usuall y corresponded with the presence of motile bacilli. The potential for growth on slag was determined by adding slag samples to media (devoid of an electron donor) appropriate for the growth of the three Thiobaci llus species. All pulverized slag samples supported the growth of the three species.