Sonars used by a National Disaster Response Force (NDRF) team failed to detect 13 'rat hole' coal miners, who remains trapped in a 70-feet deep coal well in Meghalaya's East Jaintia Hills district since Friday.
Sonar or Sound Navigation and Ranging is a technology which applies sound wave propoagation techniques for navigation, communication and to detect any object under water.
The sonar is used mainly by Navy and water transport authorities for navigational and under water vigilance.
Meghalaya government had sought NDRF's help soon after 13 miners were trapped but an officer of the top disaster management force said that their deep divers are unable to go beyond 30 feet under water and was just waiting for water in the pit to recede.
"Three pumps running 14-16 hours could reduce the water level by 15 inch. But water level again rose, may be because it is situated close to a river," the NDRF officer said.
Meanwhile, Meghalaya Human Rights Commission headed by Justice (retd) Aftab Hussain Saikia on Tuesday registered a suo-motu case related to the case and asked the state chief secretary to conduct an inquiry and submit a report within a month.
The workers, engaged by a coal miner had entered the pit on Friday morning but 13 of them got trapped as water level increased.
One of the survivors, Nayab Ali told reporters that there were 18 miners and 17 are still stuck in the pit, situated nearly 90-km east of Shillong.
Meghalaya government has faced criticism for its reported failure to enforce a ban by National Green Tribunal (NGT) on illegal coal mining in 2014.
The NGT imposed the ban on hazardous coal mining following a petition filed by an Assam-based NGO that complained that mining had polluted waters in a river that flowed down to neighbouring Assam.
The Supreme Court will hear a petition seeking lifting of the NGT ban on January 15.
The apex court had earlier allowed transportation of the extracted and assessed coal till January 31, 2019.
Chief Minister of Meghalaya Conrad K Sangma, while admitting that illegal coal mining could be taking place, said it was not possible for the state police force to keep watch on all such activities as mining takes place in remote and inaccessible areas in the hill state.
At least 15 workers had died in 2012 after 30 were trapped inside a mining pit the rest 15 managed to come out.
The incident took place days after Agnes Kharsiang, an RTI activist in Meghalaya, was attacked by members of a suspected gang of coal miners last month after she had reportedly clicked photographs of 'illegal coal mining' and transportation of coals in East Jaintia Hills district and shared them with media.
She was critically injured and spent nearly a month in a Shillong hospital.
Kharsiang has been vocal saying politicians and police are hands-in-glove with coal miners.
Police have arrested the owner of the coal mine, Krip Chullet, while another accused is absconding.
