The re-entry of the Pike River mine is planned for May 3, the Government has announced.
Minister Responsible for Pike River Re-entry Andrew Little said there was still a lot of work to do to make the conditions of the mine safe enough to re-enter.
Little told a parliamentary committee in June last year that it was possible re-entry could be started by the end of last year, but he later pulled back from that date.
When he announced the plan to re-enter the mine in November last year, he hoped the work to breach the 30m seal inside the drift would begin in February.
The seal is yet to be breached and today Little said re-entry would be in May.
"There is still some preparatory work to do: installing compressed air lines; awaiting the arrival of underground equipment such as loaders, roof bolting rigs, a driftrunner and a refuge chamber from Australia and breaching the concrete seal at 30 metres," Little said.
"Once the 30 metre seal is breached, then the re-entry and recovery operation can begin. All things going to the current plan, the [Pike River Recovery] Agency expects we will be at this point by May 3rd."
He said an incredible amount of work had already taken place since he announced that re-entry would go ahead in November last year.
"This has included preparing bridges for heavy loads, installing a nitrogen plant, upgrading the power supply, laying many kilometres of piping for the nitrogen, drilling more boreholes, installing monitoring equipment, and purging and ventilating the drift.
"As well as this, staff have been trained on working in a forensic environment. Worksafe have been reviewing all aspects of the planning, risk assessments and supporting documentation, in order to ensure the re-entry plan is safe."
The agency remained dedicated to safety, Little said.
"Safety is a non-negotiable bottom line for the whole project and everyone involved – including the families.
"There's been international expert consultation and the purchasing of specialised equipment to do the job. That dedication to safety will continue.
"The re-entry will only take place if all the necessary pre-conditions have been met."
It is hoped that work in the drift will enable the agency and Police to investigate what caused the explosion that killed 29 men on November 19, 2010.
An event will be organised at the site to mark this important milestone on May 3.