Indian emergency workers have said they have found the body of one of the 15 miners trapped inside a so-called "rat-hole" mine for over a month.

The illegal and dangerous coal mine located at Ksan near the village of Lumthari in the remote, mineral-rich state of Meghalaya in northeastern India was flooded on December 13.

The Indian Navy said on Thursday they spotted the body inside the deluged shaft at a depth of 160-210 feet (50-65 metres) with the help of a remote-controlled probe.

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"The body has been pulled up to the mouth of rat-hole mine and shall be extracted out of the mine under the supervision of doctors," the Indian Navy posted on Twitter.

The breakthrough comes after several attempts by navy divers to reach the trapped miners inside the treacherous mine. Efforts to pump out water have also failed.

"Our operation is continuing," SK Singh, the in-charge of the National Disaster Relief Force, told AFP news agency.

#MeghalayaMineTragedy #Flash One body detected by Indian Navy Divers using Underwater ROV at a depth of approx 60 feet and 210 feet inside a rat-hole mine @SpokespersonMoD @DefenceMinIndia @nsitharaman @PMOIndia pic.twitter.com/sP1sv6ikRn — SpokespersonNavy (@indiannavy) January 17, 2019

Indian authorities were criticised for being slow to respond to the emergency, including from the Supreme Court which called for rescue operations to be stepped up.

"Rat-hole" mines are deep vertical shafts dug mostly into hillsides that branch out into narrow tunnels to reach and retrieve coal and other substances.

A federal environment court banned "rat-hole" mining in Meghalaya in 2014 after local communities complained it was polluting water sources and putting lives at risk.

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But with an estimated 576 million metric tonnes of coal reserves in the state, the practice continues, with mine owners and the state government challenging the ban in India's Supreme Court.

At least 15 miners were killed after they were trapped in a flooded "rat-hole" mine in Meghalaya in 2012. Their bodies could not be recovered.

The slow progress of the rescue efforts has also been contrasted with the dramatic rescue of 12 Thai boys and their football coach from a flooded cave last July, which drew a massive international audience.