Features, Technology

Air Liquide nitrogen solution

Air Liquide has been providing its N2 Floxal AMSA solution to underground coal operations for decades, and continues to refine it for the modern mine.

Australian longwall coal mines traditionally used flue gas from boilers or nitrogen from mine shield solutions to control heating events and goaf sealing. These two solutions were used in tandem until a 2002 study by the CSIRO found that nitrogen was just as effective as boiler gases, and the industry moved toward a solely nitrogen-based operation.

In keeping with the trend, Air Liquide developed its Floxal Onsite Nitrogen AMSA units, which have since been adopted by Australian and international longwall coal operations.

“Air Liquide’s N2 Floxal AMSA solution is synonymous with reliability, cost-effectiveness and environmental friendliness,” Air Liquide national and key accounts manager Sajimon Joseph said.

“The fact that Floxal units can produce nitrogen at nine bargs (a unit of gauge pressure) or more helps the goaf sealing with positive pressure in the balance chamber.”

This is a sentiment echoed by Air Liquide national key accounts manager for mining and extraction Rick Edwards.

“It was a first-of-its-kind solution when it was first implemented and we have been refining it ever since,” Edwards told Australian Mining.

“The use of Floxal N2 plants for underground coal mines was only pioneered 15 years ago. The first units were built to supply 500m3 per hour and it became clear that while the solution showed significant promise, higher flow rates were needed.”

Using Air Liquide’s medal polymer hollow fibre gas separation technology, the fact the units produce nitrogen at a pressure of about nine bargs enables the inert gas in the area to be recirculated through the mine.

The medal polymer hollow fibre also allows the air to be circulated over large distances while the unit can stay close to the power source.

“These units are already giving ground-breaking results due to this unique ability to provide previously unavailable large quantities of nitrogen at much higher pressures than has been available from alternative methods and suppliers,” the company said in a statement announcing the range back in 2007.

“In a nutshell, Air Liquide’s innovative mobile systems provide some unique benefits to the mines in terms of safety, reliability and cost-effectiveness.”

The first AMSA unit was delivered to Anglo Coal’s Dartbrook mine in New South Wales in 2007, closely followed by the second unit being delivered to the Austar mine near Cessnock, NSW.

Xstrata Coal took ownership of the third unit that same year and installed it at the Oaky Creek mine in central Queensland.

“We support our customers in their development by offering innovative custom-made solutions, which helps them strengthen their efficiency and safety,” executive vice-president and member of Air Liquide’s executive committee Jean-Pierre Duprieu said at the time.

“Mining has been identified as a growth market in Australia and these important successes in the mining industry with this unique solution illustrate the group’s capacity to grow into new markets and territories.”

Air Liquide has continued to develop its coal mine AMSA solution since 2005, delivering them to coal mines throughout the country.

In 2009, the company signed a contract with Peabody Energy for the delivery of an AMSA 3000 series Floxal at its North Wambo mine in NSW after a six-month trial at the Peabody Bowen Basin mine. A contract with Fitzroy Reources for its Carborough Downs mine in Queensland followed and, in 2010, Whitehaven Coal commissioned Air Liquide to deliver a generator to its Narrabri operation in NSW.

In addition, the Kestrel mine near Emerald in Queensland also made use of a Floxal generator.

Despite the success, Air Liquide has committed itself to continuously redefining the units as the mining sector changes, including customising the units if needed.

Each Floxal unit is built to a standard design, but the company works with the customer to tailor them if needed, working to the specifications of each on-site supply system.

Guaranteeing a convenient, worry-free on-site solution is something that Air Liquide is proud to provide – and its Floxal solutions help it do just that.

“The main benefit of a Floxal is the reliability,” Edwards said.

“This is not only because of the built in redundancy of the equipment, but the fact it is a complete supply solution, backed by trained technicians and experienced local experts.”  

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