But the backfilling of voids could not match the pace of coal extraction. As the sand stowing lagged behind, the voids grew bigger. By 2011, only 42% of mining voids created in the Deulabera colliery had been backfilled with sand. This piece of information was tabled in the Odisha Legislative Assembly in March, 2011. In March this year, Chief Minister Naveen Patnaik shot off a letter to Union Coal Minister Piyush Goyal saying, "In its two underground mines, closed respectively in 1998 and 2006, MCL has just completed the sand stowing work of 5.38 lakh cubic metre against the requirement of over 9.15 lakh cubic metre." The CM’s letter points out that only 58.79% of sand-stowing has been achieved and asks that MCL complete the remaining work immediately. In fact, environmentalist Bibhudendra Prasad Das, president of Brahmani Anchal Surakshya Parishad, is sure that even less might have been done. "The percentage must be much less than what official statistics say. Ideally, wagon-loads of sand should be sent to fill the underground void on a mission mode under direct supervision of an independent body." But is MCL listening? A visit to one of the sand-stowing spots inside Talcher town says it all. I see a couple of workers manually channelling sand into a void. Only a few tractor-loads of sand are poured in every day, I am told. "At this pace, it may take three to four decades to fill the void," says Mohapatra. The dangers to Talcher township are many. "If a moderate earthquake shakes the area, a large part of the township may cave in. If any water channel of the Brahmani (Odisha’s second largest river), which flows a few hundred metres away, finds its way into the mining void, it could prove disastrous," says Mohapatra. Activists allege there is another danger lurking in the void - the formation of methane gas, which is highly combustible. Time is running out. "The void must be filled immediately or people relocated from the Talcher township," says Das. Any natural disaster could bring about a human tragedy on an unimaginable scale, he fears. But the backfilling of voids could not match the pace of coal extraction. As the sand stowing lagged behind, the voids grew bigger. By 2011, only 42% of mining voids created in the Deulabera colliery had been backfilled with sand. This piece of information was tabled in the Odisha Legislative Assembly in March, 2011. In March this year, Chief Minister Naveen Patnaik shot off a letter to Union Coal Minister Piyush Goyal saying, "In its two underground mines, closed respectively in 1998 and 2006, MCL has just completed the sand stowing work of 5.38 lakh cubic metre against the requirement of over 9.15 lakh cubic metre." The CM’s letter points out that only 58.79% of sand-stowing has been achieved and asks that MCL complete the remaining work immediately. In fact, environmentalist Bibhudendra Prasad Das, president of Brahmani Anchal Surakshya Parishad, is sure that even less might have been done. "The percentage must be much less than what official statistics say. Ideally, wagon-loads of sand should be sent to fill the underground void on a mission mode under direct supervision of an independent body." But is MCL listening? A visit to one of the sand-stowing spots inside Talcher town says it all. I see a couple of workers manually channelling sand into a void. Only a few tractor-loads of sand are poured in every day, I am told. "At this pace, it may take three to four decades to fill the void," says Mohapatra. The dangers to Talcher township are many. "If a moderate earthquake shakes the area, a large part of the township may cave in. If any water channel of the Brahmani (Odisha’s second largest river), which flows a few hundred metres away, finds its way into the mining void, it could prove disastrous," says Mohapatra. Activists allege there is another danger lurking in the void - the formation of methane gas, which is highly combustible. Time is running out. "The void must be filled immediate