Drilling will commence on Sunday to put a seal deep in the main tunnel of the Pike River Coal mine on the West Coast.
Statutory manager Steve Ellis says a drill arrived on Thursday and the chemicals to put a seal into the mine will arrive on 26 December.
Mr Ellis says once the hole is drilled, the expanding chemical Rocsil will be pumped in, at a point 2300 metres into the tunnel.
A seal is already in place at the 170-metre mark.
Mr Ellis says when the seal is in place, the tunnel can be reventilated between the seals.
He says it has taken between three days and three weeks to drill holes in the mine in the past and it is impossible to say how long this particular hole will take.