Published in June 2006 Australian Longwall Magazine

Increasing depths and increased heat output from more powerful equipment will mean refrigeration and air cooling systems will become more prevalent into the future.

There is also talk of lowering national statutory temperature requirements by 2C or 3C.

The combination of these factors has meant busy and interesting times for energy solutions company and refrigeration specialist Aggreko.

Aggreko has installed its refrigeration solutions at Bowen Basin mines including Grasstree, Crinum, Kestrel, Moranbah and Central.

UK-listed Aggreko started cooling Australian mines with its hired bulk air cooling units at Anglo Coal’s Moranbah mine in 2001. Its latest job has been to cool Anglo Coal’s new Grasstree mine where a 3MW surface refrigeration plant was installed adjacent to the main shaft supplying 80 square metres per second-plus of chilled air underground.

Aggreko installs most of its equipment on the surface for maintenance and efficiency purposes. The company opts to rent its refrigeration equipment, as this offers mines a more flexible and better financial solution than owning the quite complex, labour-intensive equipment. An added bonus is that the plant can be moved with ease from one location to another, depending on the mines’ ongoing requirement.

Aggreko said customers benefit from the hiring arrangement because operating costs include engineering support, maintenance, exposure to risk, backup support and full turnkey management.

At each job, Aggreko employees will go into the mine to assess the problems and tailor a solution for each individual mine – whether that be localised or bulk air refrigeration. Most of company’s work is for bulk air cooling, with some localised requests – particularly in roadway development.

Water servicing continuous miners arrives at the machines at temperatures nearing 40C, making this equipment a major source of ambient temperature. This is a major problem in particular for miners using bolting rigs on the side of the machine being subjected to high temperatures.

Aggreko can supply chilled water to a continuous miner where the water is transferred underground, then sprayed directly onto the machine.

Localised air cooling can be achieved by piping chilled water to a heat exchanger underground in a closed circuit. Air passing over the heat exchanger coils is cooled and moved to the affected area.

Refrigeration is increasingly being used by mines as part of a risk management approach, with growing recognition of the effect heat has on a workforce’s morale, safety and productivity.

“People are going to work far better underground if the environment is cooler. If you can take 2 to 3 degrees off the maximum temperature, the benefits can be huge for individuals and mine productivity,” said Alan Loudon, who after spending many years cooling South Africa’s deep metalliferous mines, now works as technical manager for Aggreko’s temperature control section.

“The productivity gains made far outstrip the capital cost of installing rental refrigeration solutions. Besides, you can’t put a figure on keeping people comfortable in their work environment, especially underground.”

Alan said Aggreko has placed great emphasis on developing new products and has moved this in-house to develop products unique to the company. It is currently working on research and development in high efficiency bulk air units, cooling towers and underground localised coolers.

“We like to form partnerships with our mining customers from the initial design and recommendation stage through to continuous monitoring of the conditions underground, improving and adapting if necessary as we go along. This affords the Mine Ventilation people up-to-date information on a regular basis.”