The Waterberg covers 88 km from east to west and 40 km from north to south. It has one mine only, Kumba Resources’ Grootegeluk operation, which turned out about 10% of South Africa’s run-of-mine coal production last year.
Prevost points out, though, that the total coal yield from what is mined is less than 50%. Grootegeluk’s mined area covers about 2% to 3% of the coalfield, and it has about 10% of the field’s reserves.
Twenty-one years into its existence, the Grootegeluk mine still has an expected life of 160 years. Several mining companies hold mineral rights to the Waterberg, including Anglo Coal and BHP Billiton.
Prevost says 70% to 80% of all coal companies have explored the field, and most agree it has good potential, provided a market for the coal is found.
The Waterberg coalfield is a multiseam and multiproduct coalfield with about 60% of its resources occurring at depths of 200 m to 400 m, while the rest occurs at depths of 20 m to 50 m below surface, where it can be extracted by opencast mining, as practised at Grootegeluk. This is due to the field being fault-bounded along its northern and southern limits, with the Daarby fault dividing it into a shallow western area, where Grootegeluk is situated, and a deep north-eastern area. Numerous coal seams, ranging in thickness from a few millimetres to ten metres, occur over a stratigraphic thickness of at least 120 m in the coalfield. The coal seams are cramped into 11 coal zones that can be correlated across the entire coalfield.
“The zones contain coal, but also other material, such as sandstone and shale, ensuring difficulty in mining the commodity,” explains Prevost. Due to the intercalated nature of the coal and shale from the upper part of the coal deposit, the ash content of the run-of-mine coal ranges from 55% to 65%, requiring large beneficiation plants to separate the products and the waste. This is a cost factor that deters many would-be investors in the Waterberg. Grootegeluk boasts five bene- ficiation plants, producing different products for different markets, such as metallurgical coal and low-grade coal for power plants. If a coal product with a low ash content of 10% to 15% as required is produced for export coal, a middlings coal with an ash content of about 35%-suitable for power generation is also obtained. The power-station coal obtained in such a two-stage beneficiation plant is at least 1,5 to double the tonnage of low-ash product obtained at Grootegeluk, meaning the operation’s profitability is largely due to Eskom’s need for the coal. The mine was originally established as a result of Iscor’s need for coking coal to use in blast furnaces at its steelworks.
Today, only 11% of the mine’s production is coking coal. At present, Grootgeluk has a question mark hanging over its future as a result of Iscor’s unbundling into two companies – Kumba Resources, a mining entity, and Iscor, representing the steel interests.
Observers say they do not foresee any new mines in the Waterberg coalfield being opened in the short term for various reasons. It requires large capital investment to beneficiate the coal, then also delivering low yield for coal products. The field’s geographic location, about 1 000 km from the nearest harbour, renders exports of low-ash product too expensive. This can be weighed against the Witbank, Highveld and other coalfields where the infrastructure is already existing and the distance for exportation of coal is much shorter. Production of a low-ash product requires additional power-generation capacity to burn the middlings coal as a by-product that will be obtained during bene- ficiation. This will require expansion at Eskom’s Matimba power station or a new facility to be able to accommodate any newcomers. Prevost points out that the arid region makes beneficiation extremely difficult, as this process needs water. Water is a problem also deterring Spoornet’s Coalink to establish a pipeline to transport coal from the Waterberg to Richards Bay or Maputo, in Mozambique.
A Coalink spokesperson says feasibility studies over the years have determined methods to transport coal from the area, but that the costs for both a pipeline and a rail network are too high.
At this point, it is not necessary to look at developing a transport infrastructure from the Waterberg, as Witbank and the surrounding areas have sufficient coal reserves. The Coaltech 2020 initiative to extend the life of the Witbank reserves will also have an effect on the prob- ability of any Waterberg developments. The initiative is a collaborative research initiative launched in 1999 by coal-mining houses and research and educational institutions, and is already producing positive results for the industry. The programme focuses initially on collieries in the Witbank–Highveld area, in Mpumalanga, which account for 81% of South Africa’s coal production. The main thrust of the Coaltech 2020 programme’s initial phase is to extend the life of the Witbank–Highveld coalfield, the only remaining fairly shallow and thick-seam coalfield that is close to the export market.
It is estimated that, for every year the coalfield can be extended, a potential income of R25- billion will be realised.
Participants in the Coaltech 2020 project are several coal-mining companies, the Chamber of Mines, Eskom, the CSIR, Miningtek, the National Research Foundation, the Departments of Trade and Industry and Minerals and Energy, the National Union of Mineworkers, the Mine Labour Caucus, and 12 higher-education institutions.
Despite everything against the Waterberg coalfield’s development, it is, due to the large resource base as well as the range of products that can be obtained from this coal deposit, important for the future development of South Africa’s coal resources.
A holistic approach for the future exploitation of this coalfield is necessary, says Claris Dreyer, Kumba’s principal coal geologist. All the participants should be involved, such as Eskom, Kumba Resources, Sasol, Anglo Coal and BHP Billiton.
The government, as the largest holder of mineral rights in the coalfield, will also have to be involved, Dreyer explains.
The initial focus on any further developments will have to be on the shallow opencast part of the coalfield, but an effort should also be made to determine if any products, including coal-bed methane, could be extracted economically from the deep part of the coalfield that constitutes the larger part of the resources, states Dreyer.