Er. AC Datta a chemical engineer from Jadavpur University, Calcutta and was an industrialist. Er. Datta started Metal Corporation of India (MCI) as Managing Director with Lead Zinc ore mining at Zawar mines (Udaipur), Zinc Smelting at Debari (Udaipur) and probably lead smelter at Tundu (Bihar). Govt. of India nationalized MCI and renamed it as Hindusthan Zinc Ltd. Pre independence (of India) ruler of Bikaner invited Datta Sb to start gypsum mining in his area. The mining of gypsum was started in Jhamsar, Bikaner by Bikaner Gypsum Ltd (BGL), Datta Sb as MD of BGL. Those days it was said that Jhamsar was the largest open cast mine in Asia. BGL was awarded a contract by The Govt. of Rajasthan to mine phosphate mineral from Jhamarkotra mines (Udaipur). Those were the days where companies with mining experience and machinery were rare. BGL was later taken over by Govt. of Rajasthan and renamed as Rajasthan State Mines and Minerals Ltd.