Police hope to cap the vent shaft at Pike River mine tomorrow [Sunday] - after weather conditions at the site prevented the operation from going ahead today.
Superintendent Dave Cliff said everything is in place for a helicopter to lift two 770-kilogram semi-circular steel plates into place to seal off the vent shaft.
"We're ready to go, but rain, wind and low cloud around the site have delayed the lifts today," he said. "We need to ensure conditions are safe for what is a challenging helicopter operation.
"At this stage we plan to try again tomorrow morning, when conditions are expected to be favourable.
"The ongoing operation at the mine is continuing, however. The GAG unit is working as normal to stabilise conditions inside the mine."
The cap on the vent shaft is expected to increase the efficiency of the GAG unit and improve the stability of atmospheric conditions inside the mine.
Once the cap is in place and monitoring indicates a stable environment, work will begin on phasing out the GAG engine and introducing a nitrogen-generating unit.
"When the GAG process to extinguish the fire and reduce oxygen levels is complete, the next stage is to pump nitrogen into the mine to maintain an inert environment and increase the cooling process," said Superintendent Cliff.
A nitrogen-generating unit has been sourced in Australia, and planning is currently under way to bring it to the mine.
For more information: Police media liaison 027 5015742