A landmark project currently being undertaken by mining equipment manufacturer Sandvik Mining Systems is the overland conveyor for Sasol Mining at its Shondoni shaft, in Secunda. When completed, it will be the longest conveyor of its type anywhere in the world.

The 21-km-long conveyor is under construction as part of a project by Sandvik Mining Systems to provide a turnkey materials handling solution from the mining face to the company’s coal-to-liquid facility on the other side of town.

“Apart from the distances and high volumes of run-of-mine coal required, the conveyor also needs to span a number of waterways and roads and to skirt populated areas without impacting on them,” says Sandvik market development and sales manager Rudi Pieterse.

The design also incorporates a more energy efficient drive system that reduces power consumption and precludes the need for a midway transfer point and associated infrastructure and manpower.

Pieterse explains that the project comprises other conveyors as part of the overall system and begins underground with a shaft incline conveyor to transport coal from the mine’s main ore pass to the surface. This conveyor has an impressive incline and a capacity of 3 600 t/h, which requires power from its massive 3 MW installed variable- speed drive to deposit the coal onto the surface- level bunker conveyor.

With the same capacity as the previous conveyor, the bunker conveyor is required to lift the material to the main 15 000 t bunker. Once on top, a tripper conveyor spanning 160 m, with a 6 m lift, uses a bifurcated chute to provide even distribution of materials across the surface area and minimise drop forces to prevent degradation of the material. The material then makes its way to the main overland conveyor.

“The main conveyor takes a massive 5 MW of installed drives, four at the head and a single drive at the tail, to move the coal over the required 21 km. Complicating the overland journey, its route requires five horizontal curves to guide it through an existing corridor,” says Pieterse.

Numerous sensitive water crossings, with the longest one spanning 700 m, as well as road crossings and the close proximity of human settlements, require the belt to be completely spill free and sealed over these sensitive areas. A massive 80 t counterweight provides the required tension to keep the belt operating trouble-free without slippage at either end.

“Beyond our borders, we are undertaking other equally interesting projects, ensuring that Africa’s mines remain at the cutting edge of production. A good example of this is in Namibia, where we are currently working on a project to construct a large-scale materials handling system for Swakop Uranium’s Husab mine,” he says, adding that the system comprises both overland and in-process conveyance systems to transport ore material from the mine to the processing plant in an efficient and safe manner.

The mine’s production will more than double the total current uranium production of Namibia and will push Namibia’s volumes past those of Australia, Canada and Niger to second place among the world’s uranium producers, behind only Kazakhstan.

“These and other similar projects across the continent provide a clear indication of the capabilities we have in-house and show the diverse solutions that are on offer to the mining industry throughout the continent. Whether it is coal, uranium or any other commodity that needs to be mined, we are showing that Sandvik Mining Systems has the right stuff,” Pieterse concludes.