BBE (Bluhm Burton Engineering) Projects have recently commissioned the first of two 14 MW refrigeration and bulk air cooling stations for the underground workings of a mine in western Mali. In little more than a year from contract award, they have delivered a complete turnkey project comprising two twin-compressor York refrigeration machines, Hamon condenser cooling towers, a tailor-made horizontal spray-chamber bulk air cooler, and all the associated pumps, pipework, electrics, instrumentation and control system. For this particular project, won in a competitive tender, turnkey embraced the entire project, including the complete engineering design, equipment specification, procurement, construction, project management and site supervision through to commissioning and handover to the client.

The induced draught configuration of the surface bulk air cooler allowed the selection of thermally-efficient construction materials that had several benefits in terms of cost, transportability, speed of erection and the option of future reusability. Likewise the condenser cooling tower selected for the project was a field-erected design, assembled from light-weight FRP components. The compact footprint of the entire plant ensured pipe runs are short and thermal losses are at a minimum.

The design also took into account the limited availability of fresh make-up water for the condenser cooling towers and the electrical constraints imposed by a mine operating entirely off its own generators. Modularity, flexibility, redundancy and built-in stand-by components should ensure a high system availability.

The BBE Group’s wider relationship with a mine begins in the very early days with fundamental concept level studies conducted by its Consulting division. Here the unique vagaries of climate, geothermal properties, mining method and fleet selection are assessed to determine ventilation and possible cooling requirements. VumA-3D software transforms any mine planner’s labyrinth of excavations and tunnels into a structured network of airways, to help the ventilation design engineer ascertain the optimum ventilation and cooling strategy over the planned life of the mine. Various combinations of mining layouts, methods and sequences, coupled to a selection of ventilation and cooling configurations, can be rigorously analysed in a desk-top environment to help identify the most flexible, efficient and economical solution. This process continues through the various stages of feasibility studies for both greenfield and brownfield mining projects and into actual implementation.

With a depth of experience extending from 5 000 m above sea-level, to 4 000m below surface and a breadth of experience spanning the globe, and from wisdom acquired in more than twenty-five years of existence, BBE are confident of providing modern world-class solutions. Indeed, in addition to their established head office in Johannesburg, BBE also have an office in Australia and have recently formed a new consultancy in Canada. Strategically, this links in well with their African operations as many of the newer African mining operations have owners, operators and consultants based in these two countries. Mining activity has noticeably picked up in the west in Cote d’Ivoire, Mali, Sierra Leone, Burkina Faso, Senegal and also, centrally, in the DRC.

When it comes to implementation, BBE’s Projects division provides the complete range of services for design-and-build ventilation, refrigeration and cooling solutions. Being totally independent, they are able to offer clients optimum, tailor-made solutions, using equipment sourced from the full spectrum of international suppliers. Having an established footprint across the African continent (South Africa, Tanzania, Ghana, Zambia, Mali), they are familiar with the broader logistics relating to transport and the selection and management of local contractors for the construction phase of the project.

During the operational phase of a mine, ventilation and cooling planning are constantly refined to satisfy the constantly-evolving mine planning. In this modern world of autonomous mining methods and the inter-connected ‘internet of things’, VumA-Live has been developed, in-house, to provide constant vigilance on key underground ventilation parameters and can control and monitor the performance of ventilation-on-demand sub-systems that are gaining in reliability and popularity. BBE’s well-established Energy division and its newly-created Automation divisions provide the focussed engineering skills to identify and enhance energy-saving strategies.

Sensitivity to the generally high cost of power, and time-of-use tariff structures, coupled to the cyclical nature of many mining activities, have created opportunities for embedded artificial intelligence to yield some significant savings. The challenge is to achieve this with the minimum of sophistication and with simple reliable hardware.

Closer to home, in South Africa, BBE Projects are busy with underground refrigeration and air cooling installations at Sibanye Gold’s Driefontein Mine and Palabora Copper and have recently started work on a new surface refrigeration and underground bulk air cooler project to breathe new life into one of the country’s oldest gold mines, in Barberton. On the ventilation side, BBE Projects have recently completed the construction of another pair of fan stations for PTM’s Maseve operation.

On the design side, BBE Consulting is busy with preliminary work on a number of new and young mining ventures, notably Venetia Diamond and two potentially large platinum mines in the Waterberg district of the northern limb.

The cooling of Africa’s underground world is in BBE’s competent hands. Whether it is desert heat, high humidity, high virgin rock temperatures, or heat from mobile equipment, the BBE Group of companies can advise, design and build any ventilation and cooling requirements, from feasibility study through to implementation and commissioning.

Being significant energy consumers, the efficiency of these systems has always been a priority in their designs and the increasing cost of energy has seen the rapid expansion of the energy division and the active pursuit of optimisation in both ventilation and cooling systems. Ventilation- and Cooling-on-Demand are very topical and can be intelligently implemented when combined with the powerful, live, network-modelling software VUMA-Live.