After multiple obstacles and delays, the first steps have been taken in the $36 million plan to explore the 2.3 km-long entry tunnel at the Pike River mine.
Families of victims were emotional yesterday after a three-person team entered the mine to begin the search for remains and clues as to what caused the explosion which killed 29 men in 2010.
Tracey Keane-Harvey, whose son Riki died in the disaster, hopes for justice.
"It was very emotional ... but it has been good finally to get to this stage."
Pike River Recovery Agency chief executive Dave Gawn told Morning Report there were tears and cheers yesterday and it was a significant step forward.
However, they were not underestimating the amount of work still to be done.
The mine behaved "exactly as we expected", Mr Gawn said, and it appeared "nothing had changed" in the environment and the infrastructure in the mine since it was sealed.
"That's very positive and certainly points to smoother rides ahead in terms of what we anticipate finding in the mine itself."
This afternoon the crew would continue to advance the ventilation system to the 170m mark in the entry tunnel - known as the drift - where work would be done on the seal.there.
He said there would then be a pause for pressure tests to understand the ventilation and atmosphere behind the 170m mark.
"And then after about five to seven days we will then start to disestablish the 30m seal, remove all of the water infrastructure.
"That will take about six to eight weeks."
While that's happening, Mr Gawn said he, agency chief operating officer Dinghy Pattinson and other experts will be putting together the final detail of the plan to go in beyond the 170m deal.
"And that plan, in part, depends on what we learn in terms of how our mine actually responds to our activities in that next six to eight weeks."
He said the agency still anticipated being able to hand the mine back to the Department of Conservation by the end of this year.