It could take up to five years to recover the remains of the 29 Pike River miners, an expert employed by the families says.
The timeline contained in the draft report drawn up by Bruce McLean of the Project Company Limited, is speculative as the mine has still not been sold, and buyers appear nervous about impending new mining legislation.
Mr McLean said if the mine sale was unconditional by August, a new 700m tunnel to bypass the large rockfall could be completed by December 2012.
Recovery could be completed by June 2015, but he warned it could take until mid-2017.
Mr McLean said doing nothing was not an option - the mine rose upwards, so could not be flooded.
The seals would deteriorate over time, which meant there could be further explosions.
Lawyer for the families Nicholas Davidson QC said if the mine did not sell, the role of the Government would be crucial.
Mr McLean's report assumes that the new mine owner will have to install a second escapeway and road access to the main ventilation fans. It also allows for significant exploration drilling.
