The Defence Force has completed stage 1 of the plan to re-enter the Pike River Mine.
The five day operation involved clearing the top of a hill so concrete can be poured down the ventilation shaft to help stabilise the mine's atmosphere.
More than 30 air force and army personnel have removed 35 tonnes of debris from the mine's ventilation shaft, making use of one of the air force's new NH90 helicopters.
Squadron leader Anna Shaw says aside from one day of rain, the complex operation went without a hitch.
The work is the start of a more than $7 million government-funded recovery effort aimed at finding the remains of the 29 men who died in the mine when it exploded nearly three years ago.