Families of the trapped miners wait anxiously while progress appears to hang in limbo.
Prime Minister John Key has been been in the area supporting both the families and the rescue teams since the explosion at the mine, which is situated near Greymouth on the west coast of New Zealand's South Island.
Half-hourly testing of air samples from the mine are still showing dangerous levels of carbon monoxide and methane gases, John Dow, chairman of Pike River Coal Mine told The Press.
Company CEO Peter Whittall said a specialist crew had succeeded in drilling the bore hole. The final few metres of the 162 metres to be drilled would be finished with a diamond drill bit to lessen the possibility of creating sparks.
"Once that hole is open we can start deploying a number of different techniques," Whittall said, according to TVNZ.
The testing of several gas samples will be required before the final go-ahead is given. The rescue team is putting contingencies into place for a large scale operation.
A New Zealand Defence Force robot fitted with a camera is waiting at the mine and will relay information on whether the rescue team can proceed.
A fibre optic cable to power the specially-adapted robot has been sent from Christchurch where it was being tested.
"We are still optimistic," Tasman Area Police Superintendent Gary Knowles told The Press. "We are keeping an open mind. We are planning for all possible outcomes including the loss of life."
