More than 100 rescue personnel of the National Disaster Response, State Disaster Response Force and civil defence have been pressed into service to help evacuate 13 people trapped in an illegal coal mine in Meghalaya’s East Jaintia Hills district, NDTV reported on Saturday. The labourers have been trapped since Thursday in the 320-feet deep illegal mine near the Lytein river after it got flooded.

Dozens of emergency workers were at the site on Friday to pump water out of the large trench. According to unidentified officials, the water inside the mine is around 70 feet deep.

“The focus is on the rescue operations in the area. We are concerned about them,” said Meghalaya Chief Minister Conrad Sangma. “The NDRF and the police are leading the operation.”

The operation was called off on Friday night in the absence of light, Northeast Now reported. Deputy Inspector General of Police in-charge Western Range AR Mawthoh and Superintendent of Police of East Jaintia Hills district Sylvester Nongtnger visited the spot. Rescue personnel and divers used boats to search inside the flooded coal mine and other accessible areas. Poor visibility inside the mine and no available map has made it tougher for rescuers to locate the trapped labourers.

“Rat-hole mining often has many channels and tunnels deep inside, so finding the miners so fast is a very challenging task,” East Jaintia Hills Deputy Commissioner FM Dopth told the Hindustan Times. “The mine is still filled with water and we are pumping it out but where it’s coming from can only be ascertained after the water level recedes.”

Although the chief minister had earlier denied that illegal mining was taking place, Sangma on Friday admitted it was a possibility. “I think appropriate action will be taken at the appropriate time against people involved in illegal mining,” he said. “This is not something acceptable to us.”

The police on Thursday registered a complaint against the unidentified owner of the rat-hole coal mine, who is missing. In 2014, the National Green Tribunal had banned unscientific and unsafe rat-hole coal mining in Meghalaya. The technique entails digging small vertical pits to reach the mineral.

The labourers have been identified as Omor Ali, Mezamur Islam, Mominul Islam, Shirapat Ali, Mozid Sk, Raziul Islam, Amir Hussain, Munirul Islam, Saiar Islam, Samsul Haque, Chal Dkhar, Iong Dkhar, and Nilam Dkhar.