An Australian company charged the Pike River Coal receivers about $170,000 for its robot, which is still stuck down the mine two years after the fatal explosions.
So many robots were sent into the mine, never to be seen again, that it was renamed a robotic 'Bermuda Triangle'.
The first, a Defence Force bomb disposal robot, short-circuited in the wet, as did another. A third robot from the Western Australian Water Corporation was sent in on November 26, 2010, but the second explosion put an end to its work.
A water corporation spokesman said this week the receivers had used another robot in March 2011 to determine the condition of the mine. That one snagged its own cable and is still down there.
"It was being leased under a commercial arrangement. When the total cost of the lease equalled the cost of replacing the robot, the receivers ceased paying the water corporation."
The internal costs of sending in a team of people, and robot, in the immediate aftermath of the disaster, had not been recovered.
The Australians went on to help police establish if the mine was safe to enter in the recovery phase. The police reimbursed the corporation, but only for the use of the robot.
The robot the receivers used was a remotely operated vehicle, the spokesman said.
Pike River Coal receiver Malcolm Hollis said it paid off the robot over a six-month period at about $20,000 a month.
Bernie Monk, spokesman for some of the families, asked why the water corporation had not just gone in and got its robot out.
He also noted that large amounts of money had been spent leasing the GAG machine, which was used unsuccessfully in an effort to make the conditions inside the mine inert and safe for entry.
"Why not get Mines Rescue to put a rope on (the robot) and drag it out?"
Monk said the families had been told it looked like it could be as far away as 2014 before Mines Rescue could attempt entry into the tunnel (drift).
"They've got a huge workforce now to recover the drift," he said, referring to the soon-to-be redundant Spring Creek miners. "The Government has got to step up."