Placer chromite along south Maharashtra, central west coast of India

We describe here the onshore occurrence of placer chromite, its mineralogy, geochemistry and reserve potential from a 12.5 km stretch (Pirwadi-Talashil) of south Maharashtra coast, India. The sediments in the area are moderately well to very well sorted. The heavy mineral concentration ranges between 0.69% and 98.80% (ay. 18.87%), increases from north to south, and comprises of ilmenite, magnetite and chromite, whereas garnet, pyroxene, amphibole, zircon, tourmaline, rutile and staurolite are in minor proportions. The concentration of chromite within the heavy mineral fraction ranges between 0.64% and 12.35%, whereas in the bulk sediment it ranges from 0.05% to 10.90%. The chromite grains are rounded to sub-rounded, marginally altered along their border and are ferro- and magnesio-chromite varieties with 32.06-48.3% Cr2O3, FeO + Fe2O3 between 23% and 27%, and MgO between 3.31% and 14.86%. The chromite grains have been derived from ultrabasic rocks and chromitites present at the upper reaches of the Gad river. The observed occurrence and variation in the distribution of chromite is due to the differences in the sediment supply from the Achara and Gad rivers, their sorting and associated oceanographic processes. The inferred reserve of chromite is about 0.032 mt.