Police today initiated the process to complete bore hole 44 at Pike River and to commission a new hole to be drilled into the mine.
Operation Commander, Superintendent Gary Knowles said the additional bore holes would enable gas samples to be gathered from further inside the mine.
"Establishing new sampling points will help build a picture of what's going on underground and also provide possible entry points for the nitrogen."
He said there was no clear timeframe for completing the work yet.
"Because of the terrain drillers are working in its never straightforward to put in a bore hole in and the work is weather dependent."
Superintendent Knowles said the nitrogen generator had arrived in the country today and was expected on site over the weekend. The 20 tonne machine has come from Australia by ship and will be trucked to the mine site.
Meanwhile the GAG machine is still operating at the portal to the mine although operators are looking for an opportunity to stop for maintenance.
Gas sampling is continuing and indicates the GAG is keeping the environment stable.
Note: Police will provide images of the nitrogen generator to media as soon as possible.