Talcher coalfield has the country’s highest coal reserve of 51.163 billion tonnes

Natabara Ray Samant, a 70-year-old lawyer, recalls a terrifying morning in 1981 when he discovered that his four acres of paddy field had turned into a pond.

He instantly realised that it would have happened because of surface subsidence due to the extensive underground coal mining that’s carried out in this area. Odisha’s Talcher city is India’s largest coalfield. At least 12 States depend on it for coal and thermal power.

Incidents of subsidence have been occurring regularly in Talcher or ‘coal town’ over the past 38 years. In 2014, a big cavity appeared in the middle of a crowded locality near the Sai temple, leaving people terrified. More recently, in December 2018, resident Shantilata Bai watched the floor of her tiny house cave in in front of her eyes. Her family have decided to leave the gaping hole unrepaired so that they can convince authorities that they are entitled to a compensation. Samant, the lawyer, is still tirelessly fighting to bring the miners to book and get the collier to pay compensation for what he terms a ‘man-made disaster’.

In the last four decades, there have been 15 major cases of land subsidence in Talcher. The incidents are not mere coincidences. In 2007, the director general of Mines Safety had declared four villages, Atharpa, Remuan, Koilunda and parts of Talcher township, as ‘no construction zones’.

A woman collects coal along a railway track | Photo Credit: Biswaranjan Rout

Two years later, the Talcher-Angul-Meramandali Development Authority issued a public notice that stated it would not approve any building plan and would prohibit further construction here.

As the number of subsidence incidents increases, residents are now demanding to be relocated to a safer place. “The vast coal reserves here have put Talcher on the world map, but it has become a curse for us. Even a moderate earthquake will wipe us out,” says Ranjit Mohapatra, convenor of a forum that consists of people affected by the underground coal mining.

The Talcher coalfield was discovered in the late 1800s, when the first systematic search for coal was undertaken in this region. In 1857, 80 tonnes of coal were mined from the Gopalprasad area. According to Mahanadi Coalfields Ltd (MCL), a subsidiary of the public sector Coal India, Odisha ranks second, after Jharkhand, in the country’s coal deposits, with 77.285 billion tonnes.

Black diamond

Talcher coalfield has the country’s highest coal reserve of 51.163 billion tonnes. Tonnes of the black diamond have been excavated through underground and open-cast mining.

Typically, underground coal mining need not pose any threat as long as the mine voids are immediately backfilled with sand and made compact. In the case of Talcher, this is not always done.

“When I started working in the Deulabera colliery in 1974, I travelled down a 3.5-km-long underground tunnel to bring out the coal,” recollects Lalit Kumar Dehury, a former worker in the colliery. He remembers sand stowing being carried out for many years. “Tonnes of sand would be brought in wagons and deposited in the mining void in the late 1980s,” he says, but the practice soon slowed down.

Indramani Pradhan, who is nearing his retirement, shares a similar experience. “I worked as a mechanical fitter in the Dera colliery. I used to work right under the earth’s crust. We had dug four kilometres deep.”

A coal mine in Talcher town | Photo Credit: Biswaranjan Rout

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.

satyasundar.b@thehindu.co.in