Published in the June 2010 Australian Longwall Magazine

This agreement follows Air Liquide’s recent contract wins at the North Wambo, Carborough Downs and North Goonyella longwall mines over the past year.

But the Austar contract win back in 2005 helped seal the Narrabri deal, with Narrabri general manager Greig Duncan already seeing the benefits of the membrane technology when he was Austar’s senior site executive.

With the Floxal units steadily replacing older diesel-burning flue gas systems at longwall mines throughout the country, Air Liquide national product manager Sajimon Joseph said the 2000 cubic metre per hour output versions were likely to become the industry standard.

The Floxal Coal Mine AMSA units not only meet the Safety Integrity Level 2 standards in delivering nitrogen at 97% purity or higher, but offer tighter safety controls, less emissions and lower manpower requirements to operate.

Floxal Coal Mine AMSA units operate unmanned. The units incorporate an ethernet link for the mine to read the Floxal performance parameters at their control room CITECT system or anywhere on their network.

The three oxygen analysers on the unit are automatically checked each day against a National Association of Testing Authorities certified gas cylinder and are also capable of cross-checking each other, as well as activating alarms when oxygen levels are above 3.5%.

One of the unmatched features is the solar-powered integrated Teleflo telemetry, which not only sends alarms but conducts data logging of parameters to enable diagnosis and support of the system offsite.

Peabody’s North Goonyella longwall mine in Queensland commissioned the Floxal unit in November after running a flue gas generator for almost five years.

On the performance of the Floxal unit, North Goonyella ventilation officer Mike Slater said he was entirely happy.

“We hardly even know it’s here,” he said.

“Not that we don’t see the effect underground, it’s just that it gives us no trouble whatsoever – it just runs and ticks away.”

With Narrabri tackling the gassy and up to 9m thick Hoskissons seam, Duncan told Australian Longwall Magazine the technology of the Floxal unit was considered technically superior and required less maintenance than alternatives.

“Mining a thick coal seam by longwall mining creates a few challenges for sealing of the waste areas,” he said.

“The Floxal unit provides a means of forming a chamber of inert gas against the longwall goaf and inhibits the ingress of air into the waste area.”

The Gunnedah Basin mine already ordered a Bucyrus longwall in September last year that can be retrofitted for longwall top coal caving.

Narrabri will install Air Liquide’s Floxal unit in February 2011.