Rescuers get ready to sink into the mine to retrieve the trapped miners in Chenjiashan Coal, Nov. 29. There were 293 miners working underground when the gas explosion happened at coal pits some 8,000 meters away from the coalmine entrance and 127 others were rescued.(Xinhua Photo)

Rescuers arrived Monday afternoon at underground work areas in the explosion-hit Chenjiashan Coalmine in northwest China's Shaanxi Province and will continue to work asquickly as safety allows, said officials in charge of the rescue operation.

At least 25 miners were killed following a major gas explosion in the coalmine at 7:20 a.m. Sunday, and 141 remain trapped underground.

Four rescue teams have reached the underground working sites where the explosion happened.

The teams split up and headed for No. 415 and No. 416 work sites, where they have been trying to restore ventilation for further rescue operations.

Zhao Tiechui, deputy head of the State Production Safety Bureauwho is a member of the State Council work group at the scene to guide the rescue work, demanded efforts be focused on operations at No. 416 site, where 111 workers are blocked "though no efforts will be spared at the other site."

The Chenjiashan Coalmine is a state-owned venture under the jurisdiction of the Tongchuan Mining Administration capable of producing 2.3 million tons of coal a year. A gas explosion killed 38 in this mine in April 2001.

Gas explosions in tunnels can occur when a great deal of harmful, suffocating gas breaks out in a few seconds and reaches adensity of more than 12 percent in the air, creating conditions for an explosion, according to experts.

The State Council work group, which rushed to the mine Monday night, has urged greatest possible efforts to rescue the miners strapped, ensure the safety of rescuers, and take good care of relatives of the trapped miners and the injured.

A State Council investigation team will be set up to study the cause of the explosion and related work, according to You Quan, head of the State Council work group.

The work group also promised to give accurate information aboutthe rescue operation in time.