While he could not offer specific dates, ACT president Steve Barrett said there had been "excellent progress" in the system working towards approval.

"[We] stay in regular contact with the agency to provide the information they need. All signs give us confidence that the approvals will be in hand in ample time to fulfill US federal and state requirements as well as the terms of our current purchase orders and new business proposals."

Barrett said ACT was in "advanced discussions" with various mining companies for sales of the system, but would not disclose locations or entities.

To date, the company has two confirmed deals totaling $US3.2 million, one with Magnum Coal for five of its West Virginia mines, and one to an undisclosed operator for three operations in West Virginia.

"We're still in the early days and see plenty of additional opportunities ahead," said Barrett.

The ActiveMine system received approval for use in West Virginia in July, with the West Virginia Office of Miners' Health, Safety and Training being the first government regulator to certify that ActiveMine was fully functional in accordance with new safety rules requiring emergency communications and tracking systems in underground coal mines. The system was designed to meet MINER Act wireless system requirements.