Two robots have been recovered this week from the Pike River Mine drift access tunnel.
The discovery comes just a few weeks after a military robot was found, sparking hope among loved ones of killed miners that the recovery operation will provide answers about what happened.
The horror explosion in 2010 claimed the lives of 29 miners and led to a nearly decade-long fight by family members to re-enter the mine.
A second army robot recovered 944m up the drift this week is a Wheelbarrow Revolution MK8, which went in prior to the second 2010 explosion, as part of the recovery operation at the time.
The robot is about 1m high by 65cm wide and weighs 290kg.
The other robot recovered on Tuesday was 953m up the drift and belonged to Water Corporation. That robot went into the mine after the explosions.
It is about 1.3m high, 1m wide, and 2.4m long, weighing 1200kg. It carried in a smaller robot which made its way further up the tunnel and is expected to be recovered in late July.
The first of the army robots was recovered three weeks ago at 759m, and a Water Corporation robot recovered before that 532m into the drift.
All items recovered are handed to the police forensics team on site.
Anna Osborne, whose husband Milton died in the explosion, said after the first military robot was discovered its recovery was proof that the re-entry was working.
"The last time this robot saw the light of day we were being told by the mine management that our men would still be alive down there eating their crib.
"It was the start of years of lies that are finally being put to rest by this recovery."
"For years we were told that the drift was too dangerous to enter. This shows that we can get in and we can get evidence out."
Minister in charge of the recovery operation Andrew Little last month said it was "just impractical" to expect the remains of all of the fallen miners to be recovered.
Instead, the re-entry efforts were now essentially solely focused on gathering evidence in the "homicide of 29 men," he told a select committee.
Little revealed that there would be no further funding for re-entry, the cost of which had more than doubled since its inception.
Re-entry originally had a $23 million budget but the Government has already spent roughly $35m and that could reach as high as $50m.
But that, according to Little, is the absolute funding limit.
"There is always a limit to these things – I have no plan or intention of returning to Cabinet for any further additional resources."
He likened the recovery efforts to a police homicide investigation – "which is effectively what this is".