Rescue workers at the site of a mine that collapsed and flooded in India's northeastern Meghalaya state.
CNN  — 

Nearly two weeks after 15 miners became trapped in an illegal coal mine in northeastern India, rescue efforts to save them have been hampered by more flooding.

A shaft of the illegally constructed mine was flooded in Meghalaya state on December 13, trapping the men inside.

The mine’s shaft, which flooded after a nearby river overflowed, is estimated to be about 320 feet deep. The men are believed to be trapped at the bottom.

More than 80 rescue personnel, including deep-water divers from the National Disaster Response Force (NDRF) are currently working to pump out the excess water in the shaft.

Authorities have installed two pumps and state officials have reached out to experts for technical support to increase the pumps’ efficiency.

The rescue effort has been hampered by heavy rains this week.

But on December 20 heavy rains caused the river to overflow again and re-flooded the mine, raising fears that the men trapped inside might not have survived.

“The efforts are on and nobody expected this to happen,” Conrad Sangma, Meghalaya’s chief minister, told reporters Wednesday.

“The government’s duty is to continue trying. There is hope. We are not going to simply give up like that.”

The rescue effort also has been challenged by the mine’s illegal construction.

Normally, mine operators are required to produce maps that highlight tunnel passages and safety areas in case of an emergency, NDRF commander S.K. Shastri told CNN. But this mine does not have a map, said Shastri, who is in charge of the rescue operation.

The mine, constructed in a jungle in the state’s East Jaintia Hills district, was employing a method of extracting coal known as rat-hole mining. The practice was banned in the Meghalaya in 2014 by the National Green Tribunal (NGT) due to health and environmental risks but is still used in secluded pockets of the state. 

Meghalaya is home to some of the largest coal deposits in the country and the resource has been illegally mined for decades. According to the state government, the region has more than 576 million metric tons of coal deposits.