The bodies of the men killed in the Pike River Coal Mine disaster might not be recovered for years, if at all.

The devastating news was revealed to the families of the 29 victims at a meeting in Greymouth on Thursday evening with Solid Energy after the conditional purchase had been confirmed.

Solid Energy will pay an initial $7.5 million for the assets with up to an additional $25m to be paid depending on whether the mine is reopened and the level of production.

The government welcomed the sale, saying "it's committed to the recovery of the bodies, as long as it means no further risk to human life".

While Solid Energy is compelled to take all reasonable steps to recover the remains of the men who died in the November, 2010 blasts, it warns "there's only a five to 10 per cent chance of this happening".

Company boss Don Elder told Fairfax it could take up to eight years to determine whether the mine was commercially viable and if they would go into the mine.

Recovery will only occur if it is "safe, technically viable and financially credible", receivers for the mine, PricewaterhouseCoopers (PwC), said in a statement.

Pike River Coal Limited was placed in receivership on December 13, 2010 following the fatal explosions.

Spokesman for the families, Bernie Monk, whose son Michael, 23, died in the mine, told the New Zealand Herald they had "got a reality check".

Mr Elder told the newspaper that if there was one thing that had been confirmed by the tragedy, it was that the West Coast geology and mining conditions were among the hardest in the world.

The sale was conditional on a number of mostly procedural matters including transfer of the mining permit and is a positive step towards determining the future of resource development at the mine, Minister of Energy and Resources Phil Heatley said in a statement.

"Solid Energy will be expected to take all reasonable steps to recover the remains of the men in the Pike River mine in conjunction with any commercial mining at Pike River in future, provided such an operation is safe, technically feasible and financially credible."