Sept/Oct 2012

From dust to dollars

River Energy’s hunt for value in the coal fines of South Africa

By Alexandra Lopez-Pacheco

In South Africa, it is estimated that some eight per cent of all thermal coal mined ends up as fines – a form that miners have struggled to convert to revenue for decades. In that country alone, there are 60 million tonnes of coal fines discarded each year from the crushing and washing processes of mining operations, and around two billion tonnes of existing discarded coal fines. These small particles, typically less than 300 microns in size, are ending up as waste in slurry ponds and they represent a significant untapped resource.

“When the coal is put through a washing process to separate it from the rock portion, most of the equipment is based on the density of the rock or coal,” says Dale McLean, general manager of River Energy JV Pty Limited, a joint venture of White Energy Company Limited and Black River Asset Management. Coal as fines essentially slips through the cracks. “They are very difficult to process and handle and are generally discarded by the mines.”

Better briquettes

To avoid throwing fines away, they need to be lumped together into briquettes – a concept that seems simpler than it is. Traditional briquetting technology has been around for a century but is based on using binders to hold the coal together, altering its properties and making it less attractive to end users. Besides, in the past, briquetting had been used to try to upgrade low-calorific coal to a higher quality coal rather than for fines. And even in that, there was little success. This has put making briquettes out of fines pretty low on most to-do lists.

But not at White Energy, which was borne out of the potential to commercialize binderless coal briquetting technology (BCB). White Energy has an ex­clusive worldwide licence for BCB technology, which began development in the 1990s through a consortium led by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia.

CSIRO, along with U.S.-based briquetting company K.R. Komarek Inc., coal drying company TraDet Inc. and the Griffin Coal Mining Company Pty Ltd., was searching for a way to convert low-rank, high-moisture coal into an upgraded coal by turning it into a binderless briquette to add value to the end product. By 2006, the team had developed the patented BCB technology, which involves a simple thermal drying process, followed by the pressing of the briquettes that are held together by the natural bonding mechanisms of coal. According to Jason Nunn, White’s technical manager, BCB can essentially upgrade sub-bituminous coal to the heat-value of bituminous coal with none of the adverse effects of using binders.

“By taking the moisture out, you increase the energy and create a product that is much more attractive to the market,” says Nunn. The result is high-calorific content and quality that also retains the low emission profile of the feedstock ­sub-bituminous coal and can be used interchangeably with other high-ranking coals. Because the price of coal is based on its energy content, with the highest calorific count bringing in the top dollar, BCB technology does not just upgrade sub-bituminous coal’s heat-values – it also upgrades its price.

At its demonstration plant in Cessnock, Australia, White Energy has tested and analyzed coal samples of over 100 coals of various types with a 95 per cent success rate in turning fines into briquettes. This has included the successful briquetting of coal fines samples from all the major coal players in South Africa, which to date is in excess of 200 tonnes.

In 2008, the U.K.’s Black River Asset Management agreed with White Energy on the potential of commercializing BCB to recover fine coal waste in Africa. The two formed a partnership that resulted in the formation of River Energy, which is 51 per cent-owned by White Energy and 49 per cent by Black River.

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