Shortly after 11:30am Tuesday the Pike River Recovery team stepped through a door chiselled into the concrete wall sealing the mine 170 metres into the drift.
It is uncharted territory - no one has been this far since the mine was sealed off eight years ago after the explosion that killed 29 men in 2010.
The team will search the 2.3 kilometre drift, 20 metres at a time looking for any evidence of what caused the tragedy.
Chief Operating Officer for the Recovery Agency Dinghy Pattinson was one of the four who went in. He talks to Lisa Owen.