As of Wednesday, they were 2.231km inside the drift, the tunnel leading to the mine workings where the 29 men are trapped behind a massive unstable rockfall.
They will withdraw next week for the Christmas break and return on January 5.
By mid-January — just over a year after passing through the first seal at 170m — they will be as far as they can go, the way blocked by the rockfall.
From there they will return to pit bottom in stone, to do some forensic work on the side tunnels.
Police revealed last week they wanted to drill more boreholes into the mine workings.
Chief operating officer Dinghy Pattinson said the boreholes should not affect plans to seal the mine. At this stage, that should occur late in April.
Minister Responsible for Pike River Re-entry Andrew Little said this week that if additional boreholes were to be drilled, it would be part of the police investigation.
"I do not expect this will have any further implications for the [recovery agency's] work programme."
Anything to do with the ongoing investigation was a matter for police, and Mr Little said he understood a decision had not yet been made.
Police said last week they had undertaken an initial high-level feasibility study to investigate the need for additional boreholes at the mine site.
They did not say exactly what they were hoping to see; however the seat of the explosion is believed to be behind the rockfall.
— Greymouth Star
