Modern Mining December 2017

COOLING and VENTILATION

through two stages of sprays to maximise the efficiency of the BAC. BBE Projects was given access to site in November 2016 and the plant was operational in July 2017. As part of its complete turnkey proj- ect, BBE went to great lengths to maximise the use of local contractors for all civil construction and mechanical and electrical installation works. Since the commissioning of the fridge plant, the environmental conditions in the mine have improved dramatically. Management at the mine commended BBE Projects on the excellent manner in which the project was completed and the great co-opera- tion between the contractor and the mine staff to ensure that the project was completed safely and timeously. 

to negotiate the route. However, the two con- denser cooling tower cells had to be supplied in four halves to keep the module sizes man- ageable for transport. The duties of the refrigeration machines were chosen to get the best balance between economy of scale, and modularity for load matching and operational redundancy. Warm water from the bulk air cooler is pumped from the BAC to the refrigeration machines and back through a 3 200-m pipe- line. Being a low-pressure application, and predominantly in quiet intake airways, it was possible to make use of HDPE piping which has the added benefit of providing sufficient insulation properties for this particular situ- ation. The returning cold water is pumped

Above: The bulk air cooler (BAC) is an underground horizontal spray chamber located in an intake airway. Left: The finished plant room (machines insulated and floor painted).

Turnkey ventilation solution for Subika in Ghana TLT ACTOM will be supplying a turnkey ventilation solution to Newmont Mining Corporation’s Subika mine at the Ahafo complex in Ghana. The solution will com- prise two large surface fans, each 2,5 m in diameter and 3,5 m in height, and two bulkhead cooler fans in order to ensure efficient ventilation of the main shaft. The installed fans will run at an optimal effi- ciency of 87,5 %.

50 %. According to a statement made by Newmont at the time, the Subika under- ground mine is expected to produce 1,8 Moz of gold over an 11-year mine life and features ore grades of 4,7 g/t. The expansion is expected to improve mar- gins and support profitable production at Ahafo at least until 2029. According to Erasmus, factors in the mine’s overall operations were taken into consideration and the com- pany’s team concluded that a complex design would not be suitable for fulfill- ing the ventilation needs of the mine. “Our main goal was to ensure that our ventilation solution provided higher efficiency while at the same using less energy,” Erasmus explains. “This led to a simpler design and installation plan for the fans which also carried the benefit of lower costs and more efficient operation for Subika.” 

ing process for the contract to supply the fans to Subika, we were required to present not just products and costing but rather a solution. Providing total ventila- tion solutions for mining operations across Africa is what we as TLT ACTOM pride ourselves on and we leveraged our market knowledge to come up with a simple and cost-effective solution for Subika. This is what made the difference when a ventilation supplier was selected for this project,” says Luther Erasmus, MD at TLT ACTOM. Newmont received its environmen- tal permit to build and operate the Subika underground mine in March 2017 and in April announced plans to extend profitable production at its Ahafo operations by building the mine and expanding plant capacity by more than

The fan design is based on parent- company TLT Turbo’s technology while the manufacturing has been man- aged from TLT ACTOM’s headquarters in Johannesburg. Delivery of the fans to Subika was due to commence from November 2017, with the full installation taking place in early 2018. The project was brought to TLT ACTOM by DRA. “As part of the tender-

December 2017  MODERN MINING  19