The Central government's mines safety arm has cautioned West Bengal that construction of an airport city in the state's Burdwan district can be in trouble if the government allows simultaneous underground mining of coal at the same location. Bengal Aerotropolis Projects Limited, in collaboration with Changhi Airport International, Singapore, is planning to construct an airport city at Andal in the state's Burdwan district, which Coal India Limited (CIL) says will block coal reserves of nearly five billion tonne. The coal ministry has now lodged a protest against the proposed airport city. The Directorate General of Mines Safety (DGMS), in a recent letter to the state government, said that underground mining of Moira Madhujore block and simultaneously allowing surface construction of the city can render the latter vulnerable to soil imbalances. The Centre had allocated the Moira Madhujore coal block with an estimated reserves of over 680 million tonne to a consortium of companies in October 2009. The state had solicited the expertise of Tata Consulting Engineers Limited for ascertaining whether allowing simultaneous execution of both the projects was a feasible proposition. The firm, in its report in late 2010, reasoned that it was possible to do so. DG Mines Safety Satish Puri, in a letter to the West Bengal Industrial Development Corp, said that problems might occur as three major coal seams are to be developed below the air strip hangars and associated townships. Besides, no consideration has been made on designing of the pillars of coal mine in view of the fact that there would be ground vibrations during landing and take off of aircraft, Puri argued. But when the West Bengal government sought Tata Consulting Engineers Limited 's views on the DG Mines Safety's observations, the firm said that the coal extraction area would be only below the township and not below the airstrip or hangars. It said since the seams are on an average 150 metre deep, so mining would not generate any vibrations due to both landing or take off.