Gold in chromite ore of south Kaliapani mines, Sukinda ultramafic belt, Jajpur district, Orissa

Abstract

Gold in the form of cuprian grains is reported based on Electron Probe Micro Analyzer (EPMA) study of a sample received from the chromite tailing dumps of South Kaliapani mines, Sukinda Ultramafic Belt, Jajpur district, Orissa. The cuprian gold grains vary in size from 3 microns to 10 microns and are found as disseminations within the chromite host-phase. Chromite is one of the earliest minerals to form whereas hydrothermal process is characteristic of gold. The association of chromite and gold grains is therefore unusual and highly interesting. Textural features suggest that the gold grains are more likely to be genuine primary inclusions within the host chromite rather than being late stage hydrothermal products filling up cavities or open spaces. A preliminary account of characterization studies of gold grains involving back-scattered electron imaging, X-ray element ‘dot’ mapping, and qualitative elemental scanning are presented.