This work was supported by the National Science Foundation under Grant Nos. INT-8017213 and INT-8313427. K.O.A. thanks the Director;
Institute of Mining and Mineral Engineering;
University of Science and Technology;
Kumasi;
Ghana;
and the Director;
the Ghana Geological Survey for their cooperation with this research. The authors also thank the management of the State Gold Mining Corporation of Ghana for providing the samples used in this research and Dr. A.O. Barnafo and Ghana National Manganese Corporation for logistic assistance. Discussions with P.M. Afenya are gratefully acknowledged;