The Pike River Mine recovery has arrived at a key point having exposed an area which could throw up clues to the 2010 explosion.
A network of tunnels called "Pit Bottom in Stone" has been reached, prompting a plea from The Pike River Families Group.
They want the forensic process to be transparent and carried out by the right people with the right expertise.
Sonya Rockhouse, whose son Ben was one of 29 miners killed in the tragedy, speaks to Susie Ferguson.
