Test Site 2. - Witbank Coalfields
Mpumalanga Province, South Africa
Coal mines within the Witbank Coalfield are owned and operated by a number of coal mining companies, while many mines are abandoned and may be classified as “derelict and ownerless” in terms of Section 46 of the Minerals and Petroleum Resources Development Act (Act 28 of 2002). This mining district covers a very large area (the catchment feeding the Loskop Dam, the most affected waterbody in the area totals 11,500 km²) and includes mines encompassing all stages of mining, from exploration through modern operating mines, mines undergoing closure. The Council for Geoscience identified a total of 209 abandoned mines in this catchment, including 118 coal mines.
The town of Emalahleni was established in 1890 to establish coal deposits located in the vicinity. This became feasible after 1894, with the construction of a railway line to Pretoria. Since then, Emalahleni and its coalfields have contributed a significant proportion of South Africa’s coal production and the area has become an important industrial town with industries including power generation and steel production.
The major direct environmental and societal impacts of mining have been due to land degradation and water pollution. Old underground mine workings have collapsed in places, leaving large areas pockmarked with sinkholes. In some cases these workings have undergone spontaneous combustion, leading to physical hazards as well as contributing to air pollution. Coal discard dumps and abandoned mining infrastructure also render land unfit for productive use.
Water pollution sources in the mining areas include operating, closed and abandoned mines, with acid mine drainage and related metal contamination forming the most important problems. Important sulphide bearing materials which can lead to the formation of acid mine drainage include the coal and discarded material and some of the overburden materials used in the rehabilitation of more modern open-pit operations. In addition, many wetlands and rivers are believed to be clogged with coal dust. Other issues include those common to most mining areas in South Africa, where with the promise or expectation of jobs resulting in the creation of large informal settlements with high levels of poverty and unemployment. The physical and pollution hazards resulting from coal mining exacerbate many of the related societal health problems.
Coal has historically formed the basis of South Africa’s energy economy, often with little attention being paid to the environmental impacts of its mining and use. In recent years this has changed, with more and more commitment to a cleaner industry being shown. In recent times however, the role of coal mining in the pollution of local rivers and streams has been under scrutiny due to increasing pollution levels in the Olifants River Catchment, which has been cited as the cause of large scale deaths of fish and large animals in the Loskop Dam downstream of mining. Coal mining has also been implicated in regional scale pollution both in this catchment and in the adjacent Vaal River Catchment which, some researchers believe, could eventually lead to a shortage of potable water for the downstream areas. In the case of the Olifants River, this would include the Kruger National Park and Mozambique, while in the case of the Vaal, the densely populated and highly industrialised Gauteng Province, including the cities of Johannesburg and Pretoria, could be affected.
For the purposes of this project, a small area of the catchment, including the derelict and ownerless Transvaal and Delagoa Bay (T&DB) Colliery and the riverine environment adjacent to the operating Kromdraai Colliery will be surveyed, to identify their impacts on the local groundwater and surface water systems.
The major expected output is a better understanding of the environmental impacts of coal mines in the Karoo Coalfields of South Africa as well as an EO-based integrating methodology for the assessment of these impacts. Specific outputs will be:
- Optical remote sensing images and interpretations.
- Geophysical images and interpretations.
- Ground-based measurements for calibration/validation of remotely sensed data.
- GIS integration of these data to produce thematic maps characterising environmental risk.