The three re-entry options to the Pike River Mine being evaluated have not presented any serious risk after the first stage of the risk assessment process taking place near Greymouth, according to the Pike River Recovery Agency.
After an explosion at the West Coast mine on 19 November 2010, the bodies of 29 men remain in the mine.
Members from the Pike River Recovery Agency, independent miners, Family Reference Group members as well as representatives from WorkSafe, New Zealand Mines Rescue, and the Department of Conservation have spent two weeks mapping risks to re-entering the mine.
Pike River Recovery Agency chief executive Dave Gawn says the process hasn't revealed any "show-stopping" reasons re-entry using any of the three options isn't possible.
"Pike River families and all New Zealanders can feel confident that the process being undertaken to ensure the safety of anyone who ends up re-entering the Pike River Mine is very thorough," he said.
"They've been poring over the ins and outs of each task required to enable re-entry via the three agreed options.
"There's still a couple of stages to go before the Agency pulls together its recommendation to the Minister, but I’m confident that at this stage, there’s nothing I’ve heard that would mean re-entry is impossible."
The three options being assessed include a single entry where the current portal would be used with "suitable safety controls" put in place.
The second option involves the construction of a small tunnel further up the hill which would be 220-250 metres in length and connect to the "Pit Bottom in Stone Area".
The third option would see a single entry with a new, large borehole created to provide a means of emergency escape.
The second stage of the risk assessment process will take place early next month before a final review is made on October 16.