Xhawula M3’s diversified strategy includes the recent mobilisation of a Cat-powered Metso Lokotrack crushing and screening plant set up to reclaim a discard dump for downstream processing and sale as power station coal.Operating throughout the Mpumalanga coalfields, the eMalahleni-based Xhawula M3 group of companies provides multidisciplinary umbrella services to blue-chip concerns as a surface and underground contractor, coal transport and logistics operator, in addition to solutions that include plant hire, earthmoving, weighbridge management, and labour hire to the mines. This scope will soon be expanded to include full-scale mining for Xhawula M3’s own account once pending South African government licence approvals have been granted. The initial downstream project scope, in conjunction with joint venture partners, includes the acquisition of an existing surface mine that will subsequently mature into an underground development. Later, there could be potential for an investment in open-cut greenfield sites. In all respects, Xhawula M3’s pure coal focus is being constantly refined through strategic diversification into niche markets. This includes the company’s coal washing business. The group already operates a washing plant at its Rondebult site, and recently invested in an additional facility at Doornrug to support a new coal dump processing project at Landau colliery’s Schoongezicht mini-pit operation, near Ogies. Xhawula M3 has secured the sole mandate for this dump, which is continuously being expanded with the addition of current arising material flowing from the mining programme. In its present form, the dump contains approximately 4.9 Mt of in-situ material, mainly coal with allied shale and sandstone compositions. “Once crushed and screened, this dump has the potential to yield around 2.5 Mt of saleable thermal coal after being washed and blended with a higher quality coal ‘sweetener’, thereby meeting the required ‘C’ grade power station specification,” explains Xhawula general manager, Sean Klopper. The dump has variations: the top level is typically weathered coal, yielding around 14 CV (Calorific Value) while deeper levels have 16 to 17 CV. C grade coal has a specification of approximately 22.5 CV, hence the need for blending at the beneficiation stage. At full ramp-up, Xhawula M3 anticipates that it will crush and screen an average of 80 000 tpm, with the capacity to increase this to around 100 000 t on a 24/7 shift operation. Processing these volumes is the task of a dedicated Metso Mobile track-mounted plant comprising a Lokotrack LT1213 impact crusher and a Lokotrack ST4.8 triple deck screen, supported by a Cat earthmoving fleet for the materials handling and loading requirements. (Barloworld Equipment is the Cat and Metso Mobile dealer for Southern Africa.) Based in Tampere, Finland, Metso is a world leader in rock and mineral processing and pioneered the development of track-mounted, fully mobile crushing and screening plants some 25 years ago with the introduction of the Lokotrack series. Each unit is purpose built to deliver the lowest cost-per-tonne and downstream product quality.
On-site at Schoongezicht, the Lokotrack LT1213 is fed by a Cat 336D L hydraulic excavator, with two Cat 966H wheel loaders performing their specific tasks, one to pick up material under the belts, plus stockpile management, and the other for loading into one of Xhawulu M3’s awaiting coal transportation trucks, each equipped with 33 t side tipper trailers.Average material sizes being fed through the crusher range between 400 and 500 mm, with a final product of approximately 50 mm. This stockpiled material is then fed through the ST 4.8 for final sizing, with the triple deck screen having a top, middle and bottom section configuration of 55 , 25 and 8 mm, respectively. This is a highly efficient screening process and the percentage of oversize is less than 1%. Sandstone and shale recovered is collected by the mining contractor on-site and sent back to the pit as rollover material for the mine’s rehabilitation phases. Expanding on the features of the Lokotrack LT1213, Barloworld Equipment Metso Mobile sales consultant Grant Gehrung, says a key advantage is that contractors can crush both blasted rock and any mineral-based demolition debris where the need is for constant, high capacity. Built around Metso’s proven NP1213M impact crusher, the LT1213 comes to market with two feeder selections, as well as an optional vibrating feeder under the crusher. “Nordberg NP series impact crushers feature a unique combination of heavy-duty rotor, wear material and crushing chamber design elements,” explains Gehrung. “This combination has proved revolutionary in improving capacity, product quality and reducing overall operating and wear costs.” The Lokotrack ST4.8, in turn, is an ideal choice for the accurate classification of up to four end product fractions: three-sized and one dependant on throughput from the reject grid. Both units operate seamlessly via their real-time onboard IC (Intelligent Control) automation software and are remotely operated for maximum on-site safety. “Automation makes it possible to run machines at constant, specific performance rates to achieve the most efficient and preset production outputs,” Gehrung continues. “Additionally, the IC system also prevents overloading caused by process fluctuations, as well as damage caused by misuse. Advanced fault diagnostics immediately pinpoint any potential problem so there’s minimal standing time.” The IC300 intelligent controller on the ST4.8, for example, monitors all functions during the screening process, with immediate machine shutdown activation – as on all Lokotrack units – where a critical fault is identified, safeguarding the overall mechanical system. Screen speed and amplitude, in conjunction with conveyor speeds, are constantly monitored and adjusted, giving higher production rates and more accurate end products. Having the mobility to deploy these Lokotrack units where and when they are needed is certainly one of the greatest cost savings. For Xhawula M3 this in-situ crushing and screening capability means that only commercially viable materials pass over the mine’s weighbridge, while the waste stays behind for collection as rehabilitation material. Klopper points out that it’s a sustainable win-win situation. “Processing the discard dump creates employment opportunities while contributing to South Africa’s energy demand.”