Police say victims' families are surprised but grateful about the decision. Photo: Pike River Recovery Agency / Supplied
Police have announced they are reopening the borehole drilling operation at the Pike River Mine to ensure the investigation team can determine what caused the first explosion in 2010.
Bernie Monk who lost his son, Michael, in the explosion described it as the best news the families had received in a decade although he was frustrated that the mine had been sealed before police inquiries finished.
Detective Superintendent Peter Read said the previous drilling operation ended in March and over the last four months, the investigation team and expert mine panel had reviewed the evidence it has gathered.
Detective Superintendent Peter Read. Photo: RNZ / Dan Cook
"The original borehole programme provided a lot of answers to questions that were vital, but we still have gaps in information so the sites we are going to be putting the new boreholes will be targeting what we believe will be evidence that either corroborates what we know already or paints the picture that we can answer the questions that will be required of us."
Police previously said the first drilling operation, which ran for 10 months, ended in March.
The experts had established further drilling was needed to ensure the investigation team had all the necessary information to reach a definitive conclusion as to what led to the first explosion.
Read said the experts had identified gaps in their knowledge and the locations in the mine where they were likely to get those answers.
"We just need to remove doubt, and be able to answer questions that are likely to be posed to us if we get to a prosecution."
The new drilling sites were centred on the A and B intake and return headings in the mine and the cross cuts between them.
"This will give more information on what's there in terms of debris, around the direction of blasts, what should be there and what is still there."
Read said it was possible images of further human remains would be captured in this investigation as they were drilling into areas where people had been working at the time of the explosion.
The eight sets of human remains captured in the first borehole investigation had not been able to be identified.
A timeline had not been set for when the drilling would begin. Read said he hoped it would be complete by next March but he could not say how long the investigation would take.
Police were also working with overseas universities on computer modelling of the first explosion, based on evidence that had already been gathered.
'Getting closer to justice'
The news of further drilling came as a surprise to some families of the Pike River Mine victims this week.
Anna Osborne, whose husband Milton died in the mine, said it came it as a total shock to her that more boreholes will be drilled to continue the investigation.
She assumed the police wouldn't be spending another $3 million on the investigation if it wasn't worthwhile and said she hoped enough evidence was found for police to take a prosecution.
"Seven years ago we were being told that all that could be done, had been done and that we should 'walk away'.
"We didn't, we fought for the re-entry of the mine's drift and for the first borehole project and now we are getting closer to justice."
Anna Osborne is still hopeful of a prosecution. Photo: RNZ / Rebekah Parsons-King
Monk said he and a number of mining experts always told the authorities not to seal the mine until the investigation was finished.
He said their advice was ignored, and the mine was sealed which was hugely frustrating.
"It's probably the best news we've had for 10 years, but it's something that we've been on about ever since day one and the authorities don't seem to be listening to anything we are saying."
Monk said if the authorities had listened to their advice they could have carried out the investigation without it costing so much.
"I do not want to hear anyone in the country say that the Pike River families have wasted a lot of money, when it's been the authorities not taking any notice and they could have done it for a quarter of the price."
Rowdy Durbridge lost his son Dan in the mine explosion. He said the news of further investigation was good.
"The more we see of the inside of the mine the better, it's going to take time but we're used to that after all these years."
Sonya Rockhouse, whose son Ben died in the mine, said police could not make any promises but she believed they wouldn't be drilling more boreholes if the situation didn't look promising.
She welcomed as much evidence being gathered as possible which might lead to a prosecution.
"The police have worked tirelessly on this investigation for several years now and we can only thank them for their commitment to justice and to truth."