Application of Petrographic Techniques to Assess In situ Leach Mining Potential:Tools Used and Types of Information Generated

摘要

The Bureau of Mines is investigating the potential of in situ leach mining (ISLM)a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and back-scattered electron imaging with a scanning electron microscope. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy (TEM).