Ilmenite placer deposits in the bays of Jaigad, Ambwah and Varvada, Maharashtra, India

Abstract

Growing demand for ilmenite owing to very limited resources of rutile and technological advancements in the industrial utilisation of ilmenite in place of rutile have excited interest in large-scale exploration for ilmenite resources. Out of a 130 km stretch of the offshore survey carried out by the National Institute of Oceanography, Goa, India, along the Konkan Coast, three prominent bays, namely, Jaigad, Ambwah and Varvada, were selected for detailed investigation. Offshore sampling was done perpendicular to the coast on a 200 m grid pattern and seismic traverses were taken up to a water depth of 18 to 20 m at an interval of about 400 m. The study has revealed the presence of two zones of enrichment, namely, of magnetite in Jaigad Bay and of ilmenite in Ambwah and Varvada Bays. The ilmenite-rich sands are inferred to be palaeo-placers; the magnetite-rich sands are derived from the Deccan basalts. The ilmenites contain about 55 percent TiO sub(2) and the magnetites have a maximum of 55% Fe sub(2) O sub(3) and 25% TiO sub(2). At an estimated thickness of 4 m, the ilmenite reserves in the surveyed area are inferred to be about 21 million tons. This estimate refers only to the sandy bed in the inner shelf region; this bed continues below the clay layer and hence, the area beyond the sandy zone may indicate much larger reserves of ilmenite in this region