Tungsten Mineralisation near Koregaon, Gadchiroli District, Maharashtra, Western Bastar Craton, Central India

ABSTRACT Tungsten mineralisation in the form of scheelite has been identified for the first time near Koregaon in Gadchiroli District, Maharashtra. The mineralisation is hosted within a lensoidal syenite body intruding the Archean Amgaon Gneisses of the Western Bastar Craton. Scheelite occurs as disseminations and stringers associated with quartz veinlets in a pink to greyish-pink syenite body extending ~2.0 km in strike length. The syenite, trending NNW–SSE to N25°E–S25°W, is extensively permeated by late-stage quartz stringers and veins. Systematic sampling along three profiles yielded tungsten (W) concentrations ranging from 287 to 719 ppm, with one anomalous value exceeding 1% W. Excluding the outlier, the average W content (~526 ppm) in the Koregaon syenite indicates a significant low-grade, large-tonnage tungsten mineralisation system. Associated hydrothermal alteration includes silicification, K-feldspathisation, and incipient boron metasomatism. A conceptual resource of ~75 million tonnes of tungsten ore averaging 0.05% W is estimated to a depth of 100 m in the Koregaon syenite body, based on surface sampling and analytical data from 21 representative rock samples. Given tungsten’s strategic importance and India’s reliance on imports, the Koregaon syenite, marked by anomalous W enrichment and hydrothermal overprint, merits detailed exploration.