South Africa's Coalfields – a 2014 Perspective
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South Africa's coalfields – a 2014 perspective 1Hancox, P. John and 2,3Götz, Annette E. 1University of the Witwatersrand, School of Geosciences, Private Bag 3, 2050 Wits, South Africa; [email protected] 2University of Pretoria, Department of Geology, Private Bag X20, Hatfield, 0028 Pretoria, South Africa; [email protected] 3Kazan Federal University, 18 Kremlyovskaya St., Kazan 420008, Republic of Tatarstan, Russian Federation Abstract For well over a century and a half coal has played a vital role in South Africa’s economy and currently bituminous coal is the primary energy source for domestic electricity generation, as well as being the feedstock for the production of a substantial percentage of the country’s liquid fuels. It furthermore provides a considerable source of foreign revenue from exports. Based on geographic considerations, and variations in the sedimentation, origin, formation, distribution and quality of the coals, 19 coalfields are generally recognised in South Africa. This paper provides an updated review of their exploration and exploitation histories, general geology, and coal seam nomenclature and coal qualities. Within the various coalfields autocyclic variability is the norm rather than the exception, whereas allocyclic variability is much less so, and allows for the correlation of genetically related sequences. During the mid-Jurassic break up of Gondwana most of the coals bearing successions were intruded by dolerite. These intrusions are important as they may cause devolatilisation and burning of the coal, create structural disturbances and related seam correlation problems, and difficulties in mining operations. Whilst many of the coalfields have been extensively explored and exploited, those in the north of the country have until recently received much less attention. Four coalfields occur partly or wholly within the Limpopo Province of South Africa and these may contain as much as 70% of South Africa’s remaining coal resources. These coalfields in particular have been the focus of recent exploration due to the presence of large coking and thermal coal resources, as well as for their coal bed methane potential, resources that need to be unlocked regards to maximum benefit and minimal environmental degradation. South Africa’s coals have been also recently addressed as palaeoclimate archives recording Gondwana’s postglacial climate amelioration by major changes in land plant communities, and proving high-resolution palyno-stratigraphy as a crucial tool to decipher climate change during the Permo-Carboniferous. This aspect of the coals of South Africa is also reviewed. Keywords: Gondwana Coal; Permian; Triassic; Coalfields; South Africa 1 1. Introduction Coal was first mined on a commercial basis in South Africa in 1857 and the country is currently the 6th largest coal producer in the world. Whilst in-roads have and are being made into clean energy (including wind and solar power) coal remains the primary energy source in South Africa for domestic power generation, and is set to dominate the energy mix for the foreseeable future. South Africa was one of the first countries in the world to use electricity on a commercial basis and presently Eskom (www.eskom.co.za), the state-owned national electricity supply utility, generates 96% of the country’s electricity. Presently South Africa is the only country in the world that operates commercial coal to liquids (CTL) synfuel plants, and coal is the feedstock for the production of a substantial percentage of the country’s liquid fuels. Coal is furthermore used extensively in the metallurgical industry (titanium, ferrochrome, ferromanganese and steel industries) and provides a considerable source of foreign revenue from exports. 1.1. The main coal producers in South Africa South African coal production is dominated by five major companies, these being Anglo American Thermal Coal (http://www.angloamerican.com/), Sasol (http://www.sasol.co.za/), Exxaro (http://www.exxaro.com/), BHP Billiton Energy Coal South Africa (http://www.bhpbilliton.com/) and Glencore Xstrata (http://www.glencorexstrata.com/), with more than 80% of the South African coal market supplied by these companies. Where relevant their individual assets are covered in this review under the relevant coalfield. 1.1.1. Anglo American Thermal Coal (AATC) AATC is a global coal business with operations in South Africa and Colombia. In South Africa the company wholly owns and operates seven mines, with a 73% stake in two additional mines. Six of the mines collectively supply 23 million tonnes per annum (Mtpa) of thermal coal to both the local and export markets. In addition the company has a 50% interest in the Mafube Colliery and Phola washing plant. They also hold a 24.2% interest in the Richards Bay Coal Terminal (RBCT) through which the bulk of South Africa’s coal is exported. 1.1.2. Sasol The South African Synthetic Oil Limited (Sasol) was established in 1950 and in 1955 produced its first oil from coal. Today Sasol is an international integrated energy and chemical company with its home-base still in South Africa. Coal mined by Sasol feeds coal into the gasifiers of Sasol Chemical Industries (SCI) at Sasolburg and Sasol Synthetic Fuels (SSF) at Secunda for conversion into crude synthesis gas. At Sasolburg SCI reacts the crude synthesis gas in a low-temperature slurry phase distillate reactor to produce linear-chained hydrocarbon waxes and paraffins. At Secunda SSF reacts the crude synthesis gas in the higher-temperature Sasol advanced reactors to produce, in one step, C1 to C20 hydrocarbons, including synthetic crude oil for downstream refining and fuels production. Gasification also yields essential co-products including ammonia, sulphur, phenolics and pitch for speciality carbon products. The chemical streams are routed through various downstream processes to produce the likes of ethylene, propylene, solvents and alpha olefins. 1.1.3. Exxaro Exxaro is one of the largest South African-based diversified resources groups. Its coal assets include eight managed coal mines, from which the company produces some 40 Mtpa of local and 2 export thermal coal, as well as soft and hard coking coal. They operate both the world’s largest opencast coal mine and coal beneficiation complex. Exxaro also produces char and related products for the rapidly growing ferroalloys industry. 1.1.4. BHP Billiton Energy Coal South Africa (BECSA) BECSA is 90% owned by BHP Billiton, a leading global resources company. The company’s coal assets include four primary coal mining operations as well as three processing plants, from which it produces thermal coal for the South African domestic and export markets. 1.1.5. Glencore Xstrata Glencore Xstrata is one of the world’s largest global diversified natural resource companies. The company was formed following the merger of Glencore International plc and Xstrata plc, which was completed in May 2013. The histories of the two companies have been inextricably linked since March 2002 when Xstrata acquired Australian and South African coal assets of Glencore, the largest shareholder in Xstrata at the time. 1.2. Academic research and previous reviews Much academic research has been undertaken on South Africa’s coal deposits with the hedeys being in the late 1980’s and 1990’s. The economic aspects of South Africa’s coal deposits were last discussed in any real detail in the seminal papers of Volume II of the 1986 Mineral Deposits of Southern Africa (Anhausser and Maske, 1986), where the coalfileds of South Africa were presented in order of increasing rank. Following on this work a number of review papers were written detailing the coalfields of South Africa, the most important of these being: a review of the coalfields of South Africa in Bulletin 113 (Barker, 1999); a review paper on the Permian coals of southern Africa by Cairncross (2001); and a paper on the characterisation of the coal resources of South Africa by Jeffrey (2005a). Two events occurred in the 1990’s that had a positive impact on what is known about South African coals. The first of these was the establishment of the Fossil Fuel Foundation (http://www.fossilfuel.co.za/) in late 1994. Since 1995 this organisation has hosted numerous coal technical events, many of which have been region or coalfield focused and at which much new knowledge has been disseminated. The second was the establishment of the Coaltech 2020 Research Programme (http://www.coaltech.co.za/) in 1999. This programme is a state, industry and academia backed collaborative initiative aimed at research and technology advances that will enable the South African coal industry to remain competitive and sustainable to the year 2020 and beyond. Two major changes have taken place this century in the South African coal industry. The first and most important of these being the implementation of the new Mineral and Petroleum Resources Development Act, 28 of 2002 (MPRDA). The MPRDA defines the State’s legislation on mineral rights and mineral transactions in South Africa and entrenches a “use it and keep it” principle, thus preventing the hoarding of mineral rights to the exclusion of new entrants to the minerals industry. The second change, which is partially driven by the former, is the emergence of a number of new junior and mid-tier coal miners, marking a swing away from an industry that was previously dominated by only a few major producers. This in turn has led to much information becoming freely available on various company websites, as well as on the Canadian Stock Exchanges System for Electronic Data Storage and Retrieval (SEDAR). 3 This paper draws from all these previous works, especially the papers of the 1986 Mineral deposits of southern Africa (Anhausser and Maske, 1986), as well as from an extensive historic literature, numerous personal files and notes provided to the senior author by Dr Tony Cadle, various open- file reports and company websites, as well as field experience gained by the authors over the past 20 years.