Shillong, Jul 13 (IANS): The National Disaster Response Force (NDRF) team Friday called off the operation to rescue 15 miners trapped in a flooded coal pit in Meghalaya since July 6, an official said.

The miners got trapped in a mine in South Garo Hills district last week Thursday after they accidentally punctured the wall of an abandoned mine, filling their mine with gallons of water.

"The NDRF has called off their operation expressing their inability to rescue the miners as the team members could endanger themselves inside the flooded mine, which is on the verge of collapse," Davies R. Marak, the district police chief of South Garo Hills, told IANS.

The special team, which began its rescue operation Thursday morning, had brought all necessary equipments to pull out the men from what are called "rat-hole" mines, but to no avail.

"Scuba divers did make their attempt to enter inside the coal pit but the formation of toxic gas in the pit has forced them to come out," Marak said.

However, district authorities would continue to pump out the water and make all efforts to rescue the trapped miners, Marak said. "I don't think there will be any survivor and if anyone of them comes alive from the pit it will be only a miracle."

The NDRF is a unit created by the government for specialised response to natural and manmade disasters.

Ten water pumps have been deployed to pump out the water from the mine.

Three people have been arrested by Meghalaya Police on charges of negligence - mine owner Kudon A. Sangma, Punjab-based mine operator Gurdeep Singh and the head of the labourers identified as "captain".

Meghalaya has a total coal reserve of 640 million tonnes. The coal is high in sulphur content and is mostly of sub-bituminous type.

Most of this coal reserve is mined unscientifically by individuals and local communities. Due to unscientific coal mining, the water sources of many rivers, especially in Jaintia Hills district, have turned acidic.

Mining activities in Meghalaya are controlled by the indigenous people of the state who own the land.

The coal is extracted by primitive surface mining method called "rat-hole" mining that entails clearing ground vegetation and digging pits ranging from five to 100 sq.m. to reach the coal seams.

Workers and children go deep into these holes and extract the coal using traditional tools. Makeshift bamboo ladders take miners down into the pits to chip away through two-feet-high tunnels.

Once the coal has been extracted these mines are abandoned and left exposed in several instances in the state. In Cherrapunjee, once famous for its heaviest rainfall, environmental abuse has almost reduced the region to a barren landscape.

The region is now pockmarked by abandoned "rat hole" coal mines and barren hills. Similar is the case in other districts of Meghalaya.

The high-sulphur, sub-bituminous coal is used primarily for power generation and as a source fuel in cement plants in India and Bangladesh.