Heavy mineral placers off Kalbadevi Bay, Ratnagiri, Maharashtra

Abstract

Sedimentological and heavy mineral studies were carried out for two offshore profiles in the Kalbadevi Bay, Ratnagiri, Maharashtra. The surface samples from the Bay were collected during pre- and post- monsoon period (i.e. in May and October respectively) and studied to find out effect of south-west monsoon on the distribution. It is observed that greater than 95 % of the sediments comprises of sand and comparatively, post-monsoon (October) sand content is higher than that in pre-monsoon (May) and transitional period (January). Fine sand (0.125 mm) contains abundant magnetites during pre- and post- monsoon period. Ilmenite shows slight increase in concentrations from fine sand to very fine sand (0.0625 mm) from pre- to post-monsoon period. The magnetite concentration along both profiles varied from 0 to 44 % during January and May (Pre-monsoon), and increased from 3 to 91 % during October (post-monsoon). Ilmenite concentrations showed mixed behavior, which varied from 0 to 100 % in January, 52 to 100 % in May, and 8 to 96 % in October. The data obtained is useful to decide the operations of offshore placer mining system in the Kalbadevi Bay.