Ranchi, Dec 31 (IANS): The number of dead in Thursday's Jharkhand coal mine cave-in has reached thirteen with the recovery of two more bodies on Saturday, police said.

"Two more bodies have been recovered on Saturday. The rescue operation is going on. There are chances of some more people still trapped in the debris," said a police spokesperson to IANS.

The tragedy occurred at the Rajmahal Opencast Project of Eastern Coalfields Limited (ECL) around 7.30 p.m. on Thursday.

The relatives of those killed took the visiting ECL officials hostage on Saturday morning at the accident site. Police, however, managed to rescue them after three hours.

Rescue operations were being carried out by the National Disaster Response Force with assistance from the ECL, Bharat Cooking Coal Limited (BCCL), the state government and experts.

In a statement, the Coal Ministry said that senior officials from the Director General of Mines Safety (DGMS) were at the site and have started an enquiry into the incident.

The Coal Ministry has termed the incident "unprecedented".

An area of 300 metres length by 110 metres width solid floor of the overburden dump area slid down by about 35 metres involving around 9.5 million cubic metres of earth material.

"This could be due to failure of the bench edge along the hidden fault line/slip," it said.

Besides the probe by the Director General of Mines Safety, a "high level committee of experts" was constituted by Coal India Limited (CIL) to investigate the causes of the accident.

The Raghubar Das government has also announced a compensation of Rs two lakh each to the families of the deceased and Rs 25,000 for the injured.