W-Li Potentials in the Tailing Dumps of Rewat Hill, Degana, Rajasthan, NW India; Constraints from Petrography and Geochemistry

Abstract

The largest tungsten deposit at Degana in NW India, hosted in Neoproterozoic (ca. 827±8.2 Ma) peraluminous granite emplaced within Delhi meta-sediments, characterized as vein and greisen types hydrothermal multi-metal deposit. A number of NW-SE trending quartz and pegmatite veins, intruded in granite, host tungsten and lithium of economic significance. Extensive mining for tungsten ore in the past resulted in huge amount of tailing dumps on hill slope of Rewat hill all over. These tailing dumps mainly contain greisenised granite, pegmatite and quartz-mica-wolframite veins which host anomalous W-Li-Sn-Mo-Ta multi-metals. In this study, we provide first-hand information on W-Li and associated rare metals potential of tailing dumps of Rewat hill using petrographic study and geochemical analysis. A total 7 samples from tailing dumps were analysed by ICP-MS indicate significant W values which ranges between 201.47 ppm to 2647.83 ppm with an average of 748.51 ppm, Li (1006.92 ppm to 6701.43 ppm, avg. 2743.64 ppm), Sn (22.77 ppm to 438.87 ppm, avg. 96.49 ppm), Mo (3.43 ppm to 254.21 ppm, avg. 63.0 ppm) and Ta up to 53.09 ppm. Ore beneficiation study on tungsten ore from tailing dumps by NML indicated that at 5% WO₃, the grade of the pre-concentrate; a recovery of > 60% could be achieved whereas at 30% WO₃ grade the recovery is about 46%. However, IBM results indicated a recovery of 59.8% with 66.30–66.50% WO₃ grade of final concentrate from tailing dumps having assay value between 0.14%–0.15% WO₃.