Power generation in South Africa is heavily reliant on coal but before the coal can be used by Eskom, it must first be crushed, sized, washed and dowatered. This process is undertaken in coal washing plants and is arguably most effectively achieved when a single company is able to undertake the engineering design, construction and commissioning of the plant, ensuring its overall integrity.

In 2008, HCI Khusela Coal approached K’Enyuka to conduct a Project Status Review of the design and construction of its coal washing plant at the opencast Palesa mine near Bronkhorstspruit, Mpumalanga, where construction had just been initiated.

“Our mandate was to determine ‘Approved for Construction’ status,’ explains David Ireland, Project Manager at K’Enyuka. “On completion. K’Enyuka was appointed to assume project management and complete the full detailed design, procurement, construction and commissioning processes on an EPCM basis.”

The 300 t/h coal washing plant will bonoficiate raw coal to a level suitable tor sale to Eskom. It will operate on a continuous basis for six working days per week, or 6 000 operational hours per annum. “Later, the plant will be upgraded to treat 700 Vh (nominal) head feed,” continues Ireland, “so it was important to ensure that the plant design could make provision for this doubling of capacity at a later date, together with the incorporation of spiral plants and the use of second-stage, low-gravity washing modules.”

The processes of the coal preparation plant include crushing, screening, dense media separation, thickening, with centnfuges being employed for dewatenng the final product together with the associated materials handling systems.

“Our main challenge was to re-engineer the plant within a very tight timeframe,” Ireland says. “This also had to be done at a stage when construction was already underway, albeit in its infancy. This meant that management had to be pinpoint accurate, and planning and utilisation of both internal resources and sub-contractors honed to the maximum. The project was planned to a high level of detail and controlled down to every drawing issued to the sub-contractors and to the supply and delivery of every item of equipment to site.

To make up valuable time, we had to use both fast-track and ‘crash’ engineering and construction tasks, with contractors establishing on-site prior to design completion,” he says. Construction was undertaken in a systems orientated manner so that hot commissioning of the front-end of the plant through to the intermediate stockpile could precede hot commissioning of the wash/dense medium separation plant.

K’Enyuka completed tho project within a tight timeframe, with the plant producing its first product on 17 February 2010. “The project was handed over to the client without any lost time injury,” states Ireland. This involved work in excess of 240 000 man-hours, a significant achievement.

Source: Modern Mining