The Polish GAG jet engine was used at the West Virginia mine from October 1 through to October 19 and operated by Polish technicians on a 24/7 schedule.

The purchase and operation of the equipment was handled by US-based international mining services company, MICON.

The GAG technology was originally developed by the Polish and utilizes the exhaust from a small jet engine to produce low oxygen gases that are used to inert the atmosphere in a mine.

The inert exhaust gas from the GAG is directed down a ventilation shaft and into the mine areas that need to be inerted.

The Polish technology is similar to the GAG jet engine inertisation system flown over with a dozen Queensland Mines Rescue Service personnel and trained miners to Consol's Loveridge mine in March this year, with a few variations in the set-up and use of the equipment.

The mine originally requested the GAG jet engine equipment be sent over from Australia, however, Queensland Mine Rescue Service (QMRS) were unable to supply the technology or personnel required due to commitments in Australia.

"At the time of the request we had a staff shortage of two people (out of five operators) and it would have been difficult for us to respond both here in Australia or overseas," said Queensland Mine Rescue chairman Ray Parkin.

He said the mine had been having technical discussions with QMRS.

Pinnacle management said the closure of the mine, which has been idle since the original explosion on September 1, was due to a ventilation disruption most likely caused by a lightning strike to a borehole in a mined out area of the mine.

ACCORDING to a statement released by PinnOak parent company Natural Resource Partners last week, it was uncertain when the mine could be bought back into production.