There are 227 working underground mines and 28 mixed mines under Coal India Ltd.
"CMPDI, on behalf of Coal India Ltd (CIL), invites offers/bids through e-tendering from academic/research institutions and/or consultancy firms/organisations of India or abroad for providing consultancy services for 'study on underground coal mining in CIL - problems, potential, technology, modernisation, production and safety'," according to a tender document dated November 2, 2015.
Coal and Power Minister Piyush Goyal had earlier said that as against the output target of 37.6 million tonnes (MT) from the underground mines last fiscal, CIL had produced a little over 35 MT.
The scope for augmenting production from the underground mines, he had said, was limited on account of difficult geo-mining conditions, non-availability of large size deposits for adopting mass production technologies, inadequate experience in mechanisation of underground mines.
He had said that the major constraints in increasing coal production from underground mines, include lack of appropriate technologies to mine coal from thick and steeply inclines and multiple seams, heavy pumping out of water and adverse roof conditions.