Into the deep

2021-12-08T09:02:28+00:00 November 1st, 2021|Cover story, Operations|
Underground mining is a harsh environment, and the necessary cooling is essential to ensure a sustainable and safe operation. Image credit: Leon Louw

Underground mining is a harsh environment, and the necessary cooling is essential to ensure a sustainable and safe operation. Image credit: Leon Louw

Edited by Leon Louw

Twenty years after it pioneered modular mine cooling solutions in Australia, energy company Aggreko has released an offering for mines going deeper with the release of its latest modular bulk air coolers (BACs).

The modular 12.19m mobile BAC10000s are unique and relatively new to the mine cooling market. They are scalable, portable and boast three times the cooling capacity of the previous largest offering – the 6.09m containers.

According to Aggreko Underground Cooling Sector Manager Mitch Bevan, the BAC10000s were used at a Western Australian mine last year and will soon arrive at a mine in New South Wales, Australia.

Bevan says part of the new modular BACs appeal was their simplicity and convenience when compared to purpose-built onsite cooling plants. The new BACs uses a simple design involving pipes, chilled water and three axial fans – all comprised in a modular shipping container.

Bevan says that he expected mines in regions like Africa, Latin America, and North America to be especially interested in the company’s new product offering.

“The unit is more suited for larger installations and offers improved efficiency rather than using a large number of smaller BACs,” says Bevan.

“Capital refrigeration plants take a long time for mines to prepare for financially, as well as to install whereas we can mobilise on relatively short notice. A rental option also provides a great deal of flexibility, which is often crucial for underground vent systems where it is difficult to predict the requirement year on year.”

Aggreko re-engineered their cooling towers to come up with the 12.19m modular BAC10000s after anticipating there would be global demand for such an offering.

Deep mining more popular

According to ScienceDirect, deep mining is set to become more common. Already, deep mining at 1 000m underground is considered normal, the depth of geothermal development has reached more than 5 000m, and oil and gas exploration has reached about 7 500m

In the mining industry, effective ventilation and cooling is needed to keep the temperature within the sub 30 degree Celsius ‘safe zone’.

Long running mines have continued to grow and their refrigeration requirement grows with the mine, so BACs are appealing as they can be scaled up or easily moved onsite.

“While mines are expanding, our clients are also focused on energy efficiency, and safer operation – such as more environmentally-friendly refrigerants – and we are constantly working on new developments in these areas.

“The water-cooled BACs have less of an environmental impact seeing that the modular container sits on the ground’s surface and requires no serious ground modifications, such as concrete.

“The units only require water and power, and while some mines use diesel-generated power, as time goes on that will shift to renewable energy. Our company has made major commitments to greener energy to help miners achieve net-zero emissions by 2050. That is why we are constantly exploring and investing in new technologies.

“Currently, our water-cooled chillers use half as much power as air-cooled options, which is part of their appeal, and at the moment we are the only rental company to provide such modular and scalable products.”

The BAC10000s have been successfully used at 29Metals’ Golden Grove Mine – a high grade copper, zinc, and precious metals mine about 450km northeast of Perth, Western Australia. The mine mills about 1.44 million metric tonnes a year.

When the mine underwent an expansion which required almost two years to upscale its permanent cooling plant, a quick and effective solution was needed in time for the 2020-21 summer. Aggreko were able to quickly supply their BAC10000s to install a 4.5MWr water-cooled plant.

As well as water cooled refrigeration plants such as Aggreko’s 20-foot and 40-foot BACs, Aggreko also offers air cooled refrigeration plants (with power provided if required) and underground spot cooling solutions.

“Newer mines are also continuing to come online in Australia and around the world. We are supplying modular cooling solutions throughout the entire mining life-cycle,” says Bevan.

“We are constantly looking for opportunities to improve on our strengths to assist our clients further into the future. We provide flexible energy solutions and services to the mining sector and provide high standards regardless of a mine’s location in the world.”

According to Aggreko Australia-Pacific Managing Director George Whyte Aggreko had delivered more than 50 mine cooling projects globally, and always drew on the experience of its engineering, procurement, construction, and maintenance teams to stay at the forefront of technology.

“Aggreko’s mining services pioneered mine cooling as a rental service 20 years ago as a result of mines looking for alternatives to capital refrigeration plants. Previously, mining companies would need to use capital to install built-in cooling systems which were not scalable, modular, or as effective,” says Whyte.

“In the past two decades we have witnessed mines becoming deeper and this has resulted in the need for larger cooling capacities and innovation. The need for deeper mines in increasingly remote locations, coupled with rising global temperatures is forcing operation managers to seek affordable alternatives to cooling and ventilation systems.