Abstract
The purpose of this study was to assess the weathering of biotite under conditions simulating an active bioleaching environment. Finely ground biotite was contacted with Acidithiobacillus ferrooxidans culture solutions for up to 120 days. Biotite was altered under these conditions to interstratified structures comprised of mixed layers of biotite and vermiculite. Interlayer K in biotite was released upon weathering and precipitated with ferric iron and sulfate to form jarosite. Substantial dissolution of biotite was also associated with weathering. The data demonstrate that exposed, biotite-rich rocks in mine tailings and heap and dump leaching systems can undergo acid mediated solubilization and structural changes, which are coupled with the formation of expansive, vermiculite-like minerals and jarosite precipitation.
ACKNOWLEDGMENTS
T.M. Bhatti was partially funded through the U.S. Agency for International Development (Pakistan Participant Program) and the Government of Pakistan. Additional partial support to T.M. Bhatti and O.H. Tuovinen was received from the Finnish Funding Agency for Technology and Innovation (Finland Distinguished Professor Program, 402/06). Salary and research support was provided to J.M. Bigham by state and federal funds appropriated to the Ohio Agricultural Research and Development Center.