英语文摘：Poisonous gas jeopardizes rescue in New Zealand mine

WELLINGTON, Nov. 21 (Xinhua) -- More than 48 hours after the methane explosion ripped through the Pike River coal mine in New Zealand South Island's West Coast, gas levels were still too volatile for rescuers to enter.

A rescue team was poised at the Pike River coal mine and ready to go in when tests show the smallest window of opportunity, New Zealand Mines Rescue general manager Trevor Watts told a media conference in the West Coast town of Greymouth on Sunday afternoon.

Poisonous gas levels are being tested every half hour but it is still too volatile to enter the mine, Watts said.

There has been no communication with the miners or contractors at the horizontal mine at Atarau near Greymouth since a methane gas explosion cut power and blew out ventilation fans on Friday afternoon.

Pike River chief executive Peter Whittall (L) and police commander Gary Knowles (R) speak to the media on the rescue operation to find 29 miners trapped underground at the nearby Pike River Coal Mine site, in Greymouth on November 21, 2010. The chances of rescuing alive 29 trapped men trapped in a New Zealand mine became more remote as tests showed a fire burning underground and it remained unsafe for rescuers to enter.

Rescue teams are not allowed to enter until it is proven that there is no risk of a second explosion, police said.

Contractors are expected to begin drilling a small bore hole up to 150 meters deep on Sunday to reach one of the open areas inside the mine.

The 15-centimeter hole will be used primarily to take air samples but could also be used for items, including a camera, provided that what is sent down is electronically safe and will not cause another explosion. It will also allow rescuers to hear anyone talking.

Fresh air continued to be pumped into the mine through a shaft.

Families of some of the workers were taken to the mine Sunday morning to help them understand the situation that the rescuers are facing.

Sixteen of the trapped workers are employed by Pike River Coal, while 13 others are local contractors. The youngest of the miners is a 17-year-old New Zealander, while the oldest is 62.

According to local police, of the workers, 24 are New Zealanders, two Australians, two British and one South African.

Families of the overseas workers are beginning to arrive in New Zealand.