Tailor-Made cooling solutions for Africa’s hotspots

As underground mines reach greater depths, higher temperatures, higher humidity, and more gas emissions are encountered. This becomes a topic of interest to various audiences with very different viewpoints. Workers in the mines expect healthy and safe working conditions with an acceptable comfort level for a typically heavy workload. Mining operators wish to comply with regulations while minimizing the cost of investment and operation. Mining industry regulatory organizations demand compliance with standards for safety and health. Environmental and workers’ advocates wish to see improvements in working conditions as well as lower emission standards. Mining engineers try to design a mine within the constraints of all of the above.

Profitable exploitation must be secured amid the factors of ever-increasing energy costs, stricter conditions, and lower tolerance levels to health risks and accidents. In addition, ventilation engineers and technicians strategise to meet the demands of all parties and to provide safe and healthy working conditions underground at a minimum cost. This balancing act requires intimate familiarity with the nature of geology and the ore deposit as well as their interaction with the engineered mining operation.

The main purpose of mine ventilation systems is to maintain thermal comfort of underground personnel, remove heat from equipment, dilute mine contaminants, and provide fresh air for personnel to breathe. Underground mines need to be equipped to accurate, real-time, and intrinsically safe monitoring systems to be able to continuously assess the condition of a mine ventilation system. Underground mine workforce safety and workplace productivity rely significantly on the performance of mine ventilation and monitoring systems.

Ventilation within any type of underground mine functions in order to introduce fresh air into the work space of the workers, while simultaneously removing contaminated air from the same location. The removal of such air contaminants is also particularly important in maintaining an overall safe thermal environment that reduces any possible ignitions from occurring within the mine. The basic components of any type of mine ventilation system involve a combination of pipes, ducts, fans, cooling and heating systems, and occasionally air cleaning equipment.

Due to the extreme environment, underground mining operations make use of some of the largest ventilation and cooling systems in the world, incorporating more than one type of cooling technology, such as evaporative condensers, mechanical refrigeration plants, pre-cooling towers and bulk air coolers, in order to ensure a safe mine temperature.

These cooling systems typically work by producing chilled water, occasionally ice, to reduce the temperature of the air entering the mine, or to be sent into the mine to reduce the ambient temperature within the mine. The systems are installed on the surface, underground, or a combination of both, depending on the depth of the mine and various logistical factors.

Undoubtedly, Africa is a hot continent. Even on surface ambient conditions can be uncomfortable, unproductive and even unsafe. And it only takes a short excursion underground where the additional heat from virgin rock and mobile equipment demand some form of a cooling system.

The BBE Group, with its full spectrum of consultancy, automation, energy and projects divisions has been at the forefront of developing ventilation and cooling system technology in the mining industry for decades, providing professional engineering support in the specialised field of mine ventilation and cooling, designing and selecting the optimum combination of equipment to suit each mine’s particular life-of-mine circumstances.

The engineering designs begin with cooling systems at concept level where all aspects of energy efficiency and cooling efficacy are analysed to determine the best fit-for-purpose solution. Then equipment selection and specifications are detailed and taken through the EPCM phase, eventually wrapping the project into a simple design-and-build turnkey package.

Equipped with a professional team of specialist engineers who are leaders in mine ventilation, refrigeration and cooling, measurement and control of underground pollutants, energy optimisation and ventilation network simulation software, the BBE Group has built an excellent international reputation since inception in 1989 as it is able to undertake a full range of projects from greenfield sites to plant extensions and upgrades, while offering optimal solutions using the best combination of available equipment, tailor-made to each client’s specific requirements.

Recent and current projects include a pair of refrigeration and surface bulk air cooling (BAC) stations at a mine in Mali; a surface refrigeration and underground BAC for a mine in Barberton, Mpumalanga province, South Africa; an extension to a refrigeration plant supplying a large surface BAC at a platinum mine near Rustenburg, South Africa; an underground plant and associated BACs at a large copper mine in South Africa; an underground plant, 2 600m below surface, supplying cold water to a closed-circuit network of cooling coils; a new surface refrigeration plant and BAC supplying cold air for a dedicated cold hole into a mine in Ghana; and designs are well-advanced for a similar facility at a diamond mine in Limpopo province, South Africa.

Although the building blocks appear similar, each system is discretely tailor-made and the operating parameters carefully tuned to suit each mine’s unique situational and evolving circumstances. For the full-on turnkey packages, BBE Projects are familiar with logistics across the African continent. Wherever your hotspot, BBE is confident to provide efficient and economical solutions.