South Africa’s best-quality coal, located in the central Highveld basin, is depleting and alternative sources of coal need to be developed to supply the country with coal in the future. The quality of coal mined in the central basin is also gradually becoming poorer while the coal market is increasingly demanding a higher quality product.

According to CSIR Senior Researcher specialising in coal processing, Johan de Korte, it is expected that coal processing will become more difficult in the future as the quality of raw coal mined continues to decline. Coal processing plants will have to contend with lower-yields and more difficult to process coal.

“The CSIR's role in South Africa's mining industry is very important, therefore its role is being re-assessed and revived through initiatives such as the Mining Research Advisory Panel and participation in the government's Mining Phakisa,” says Johan.

South Africa is a water-scarce country and the coal industry is under pressure to reduce the amount of water consumed for coal processing. “A number of coal processing plants have installed filter presses to close their water circuits by filtering slurry produced. The water consumption is reduced by a factor of about three,” explains Johan.

The challenge to the coal processing industry is to process low-yielding coal to produce good quality products, and at the same time, ensure that coal mining becomes economically viable. The remaining coal is of a lower grade and requires processing before it can be used in industrial processes. Processing removes the non-combustible contaminants in the as-mined coal, which increases the effective energy content of the coal. It also lowers the sulphur content of the coal, lowering the emission of sulphur compounds when the coal is burned.

“The CSIR remains committed to innovation in the coal industry and as such, plays an important role in Coaltech - a collaborative research programme aimed at improving the sustainability and productivity of the South African coal industry,” concludes Johan.

The mining sector in South Africa is one of the country’s most critical industries, one that is responsible for a large proportion of employment, as well as the bulk of the county’s exports of precious materials. It is also one of the most impactful industries. Mining production is energy and resource intensive, therefore, it is important for the role-players in this sector to address and implement any activities or changes in behaviour that might reduce the amount of impact mining has on the environment and South Africa’s already scarce natural resources.

Prosopis is unfortunately found in communities that mostly depend on ground water for survival, consequently limiting the availiabilty of water for people dependent on these water sources.

Johan’s paper titled: Processing low-grade coal to produce high grade products was published in the Journal of the Southern African Institute of Mining and Metallurgy.