The Pike River Mine has been re-entered, the Pike River Recovery Agency has confirmed.
Three people opened the doors, checked the drift condition, and came back.
It’s the first step in a $36m plan to explore the 2.3km-long entry tunnel in the search clues as what caused the mine to explode.
The plan to re-enter the access tunnel was called off earlier in the month after high levels of oxygen were detected, making entering potentially unsafe.
The Pike River Mine disaster was a coal mining accident that began on 19 November 2010 in the Pike River Mine, 46 kilometres northeast of Greymouth.
A methane explosion occurred in the mine. At the time of the explosion 31 miners were in the mine. Two miners managed to walk from the mine.
Following a second explosion on 24 November the 29 remaining men were believed by police to be dead.
The mine hasn’t be re-entered since.