Stuart Coal, a family run mining company on the outskirts of Delmas in Mpumalanga is in the process of ramping up supply of coal to Eskom. With Eskom’s requirement for additional coal supply in future there is a need for the small- to medium-size coal suppliers to fill the production void.
In order to ensure the optimal performance of its coal fired power stations Eskom requires that coal suppliers adhere to a strict set of coal quality requirements.
DMS washing plant
In order to meet these requirements, Stuart Coal contracted Consulmet, an engineering company specialising in the design and construction of modular and portable mineral processing plants to design, build and commission a new modular 450tph coal Dense Medium Separation (DMS) washing plant. Consulmet produces a wide range of standard modular unit processes that can be configured to an individual project or client’s requirements and includes crushing, screening, DMS, spirals, water reticulation and materials handling.
The need to relocate the DMS module in future required a modular design approach to be followed. The DMS was designed with built in spillage catchment sumps thereby reducing the civils requirement and on-site costs as well as simplifying and reducing the future cost of relocation of the plant. This makes the plant design ideal for shorter life of mine operations or where multiple smaller deposits need to be mined. The modular design philosophy allowed for the plant to be fabricated, trial erected and water commissioned in Consulmet’s fabrication yard in Klerksdorp.
Trial plant erection
The trial erection of the plant ensured component fit and quality with the added benefit of reduced on site costs, reduced on site programme, as well as accelerated commissioning programme. After completion of trail erection and water commissioning the plant was dismantled, transported and erected at Stuart Coal Mine in Delmas approximately 250 km away.
Although the plant is modular in construction, the design of the plant allows for ease-of-access from a safety but also from a maintenance point of view. Maximising plant availability and utilization was a key design consideration and the plant is designed with sufficient instrumentation and control to ensure processing efficiency, as well as minimising operator input.
Key design features of the Modular DMS include a split size wash with the 4×16 mm and 16×50 mm size fractions washed in separate cyclones thereby increasing overall separation efficiency and yield. The operating density of the medium in the fines and the coarse cyclone circuits can be controlled separately ensuring optimal process efficiency. The plant further allows for a wide range of feed size distributions and qualities i.e. product yield’s to be processed.
Modular plant advantages
With the increased need for accelerated project programmes in a capital constrained market the advantages of utilising pre-engineered modular coal plants will play a critical role in the small- to medium-coal producer market. Looking at the quality of construction, and the thought processes that went into the design of the coal DMS plant, down to the detail of automation and operator safety, Consulmet can firmly place a feather in its cap.