South Africa is in need of solutions to deal with its mine water and acid mine drainage (AMD). Various research groups are currently looking into initiatives which could be developed to pro-actively deal with mine water and AMD. The ultimate goal is to create opportunities to utilise this liability in an acceptable business and environmentally-friendly way.
South Africa is in dire need of solutions to deal with mine water and acid mine drainage (AMD). With a global rainfall average of 870mm per year, SA only receives a pitiful 450mm, which makes it the world’s 30th driest country. At last year’s inaugural South African Water and Energy Forum, experts said the country was already facing a water crisis and would experience critical water shortages as early as 2020.
After President Jacob Zuma’s State of the Nation Address, there is a renewed emphasis on development and job creation. Part of the government’s plan is to develop, among other, the water infrastructure in Limpopo to unlock the enormous mineral belt of coal, platinum, palladium, chrome and other minerals. The president said in his address that an amount of R248-million will be invested over the next two years to deal with the issue of AMD on the Witwatersrand.
This money is only a small relief for a problem which is described as the most urgent threat to the country’s water and has already affected many of South Africa’s key water bodies. In Carolina, Mpumalanga, the Department of Water Affairs had to step in as the drinking water in this town was found to be contaminated with AMD seepage. According to media reports, the department appointed a rapid reaction team of scientists and engineers in February to help local authorities remove heavy metals such as iron, aluminium and manganese from the drinking water, while drinking water was trucked in from nearby Breyten and Chrissiesmeer.
According to a Water Research Commission (WRC) report, produced in 2009 and published in August 2011, the country has an estimated 10 000 km³ of hydraulically interlinked mines in Mpumalanga alone, with approximately 300 km of interlinked gold mines on the Witwatersrand. The Mine Water Research Impact Assessment report, which was done in conjunction with Frost and Sullivan, stated that most of these mines started operating at a time when legislation did not take into consideration the need for environmental management and mine rehabilitation. Thousands of mining operations have been left unrehabilitated and abandoned as a result of inadequate resources and changing market forces. The Department of Minerals and Energy’s abandoned mines database recorded more than 4 770 un-rehabilitated and ownerless mines across the country. According to the report, these mines have become the responsibility of the state and are a potential threat to our water sources. The pollution of South Africa’s scarce water resources through mining is a significant challenge facing the country.
Making mine water a contributor to growth and development Mine water and AMD is a sensitive issue for all the parties involved and while the government’s policy states that the polluter must pay, the challenge would be to find a sound business plan to make mine water treatment a profitable opportunity for government and business.
The Olifants River Resource Project, which kicked off in March, is trying to achieve this by finding a solution to proactively deal with AMD while creating opportunities to utilise it in an acceptable business and environmentally-friendly way in Limpopo. The study is a project of the Joint Water Forum (JWF) and Lebalelo Water Users Association (LWUA). About 26 mining companies that need water partnered with six to eight mines that currently have AMD to set up this system.
According to Bertus Bierman, spokesperson of the JWF and LWUA, the study examines the possibility of obtaining AMD water from the Highveld coalfields in Witbank, also known as eMalahleni. Other water sources being investigated is the upper Vaal River, where the Ekurhuleni sewerage works is situated, and mine water from the mines at Grootvlei and Zincor. The study will look at the sources, the river systems around them and examine the project’s environmental friendliness as well as the management of the whole system in the case of flooding as well as legal and institutional implications.
“We looked at how it was being done in countries such as Germany and America, but ultimately we would like to find the right technology for the correct solution in the South African situation,” says Bierman. “If the study shows the project is feasible, it will mean a 7% growth in Limpopo’s economy, while two-million people will have safe drinking water. The spin-off of job opportunities is also huge.”
Bierman says once the study is completed, the communities around the mines can have water as soon as 2014, while water is expected to flow through the system by 2015 as the mines need their water by 2016 to 2017.
Turning a liability into an asset The eMalahleni water reclamation plant, which is situated in the Witbank coalfields of Mpumalanga, has turned a major liability into a valuable asset that has created far-reaching benefits for the environment, the local community and its feeder collieries. According to the WRC report, the project has resulted in revenue generation from the sale of treated water, provision of clean piped water for the local community and has created a significant number of job opportunities.
The award-winning project was a public-private partnership that was jointly undertaken by Anglo Thermal Coal, BHP Billiton Energy Coal South Africa (BECSA) and the eMalahleni Local Municipality. It has been described as a world-class initiative and exemplary model for development, according to the website www.angloamerican.co.za.
Following over a decade of research and development, the plant was commissioned in 2007. It desalinates rising underground water from Anglo Thermal Coal’s Landau, Greenside and Kleinkopje collieries, as well as from BECSA’s defunct South Witbank Mine. By doing so, it prevents polluted mine water from decanting into the environment and the local river system, while also alleviating serious operational and safety challenges. The plant uses the latest purification technology and is currently desalinating record production volumes of 25 megalitres of water to potable quality per day. Most of this water is pumped directly into the municipality’s reservoirs, meeting about 20% of its daily water requirements. While 40 permanent positions were created for the running plant, between 650 and 700 temporary jobs were created during the construction phase.
The plant operates at a 99% water recovery rate and the ultimate goal is for it to be a zero-waste facility through the 100% utilisation of its by-products. The 100 tonnes of gypsum it produces daily is not only costly to dispose of, but is also an environmental and post-closure liability. The WRC’s report states that this industrial material can be sold as a commercial product on the local market. Two revenue-generating projects with a total value of R16-million are in the final stages of completion. The first study is looking into the conversion of waste gypsum into sulphur, limestone and magnesite. The second investigates the by-product’s use in the production of usable building products while liquid waste produced can also be used to grow algae suitable for producing health products such as spirulina or for the production of bio-diesel.
Mine water irrigation The WRC evaluated the potential of gypsiferous mine water for use in crop irrigation as early as in 1983. The major findings of research conducted by the WRC supported the use of mine water for irrigation, showing in the short to medium term, which is around eight years, irrigation with gypsiferous mine water proved to be sustainable with a negligible impact on ground water. Two commercial crops, maize and potatoes, were irrigated with gypsiferous mine water as part of the WRC study at the Smith Bros Farm. Good yields were recognised for both crops, proving that commercial production of crops under irrigation with gypsiferous mine water is feasible and highly productive. The farmer, Niel Smith, highlighted the fact that the potatoes grown using mine water were of the highest quality he had ever reaped, further strengthening the WRC’s findings that gypsiferous mine water can be very productive if used for irrigation purposes.
Mine water for irrigation purposes presents benefits such as the stabilisation of dry-land crop production, thus enabling dry-season production, whilst at the same time providing a cost-effective method of minimising excess mine drainage. Large amounts of mine water could possibly be made available to the farming community and utilised for the irrigation of high-potential soils in the coalfields of the Mpumalanga Province, where water resources are already under pressure. A significant number of jobs could be created, thus benefiting the local community and ultimately South Africa as a whole. However, the WRC’s report cautions that since water resources are already under pressure, the Department of Water Affairs may not allow the use of mine water for irrigation, but rather require that the water is treated to standards which would allow use by users who are even more productive.
New water treatment developed A new technology which may offer a solution to acid mine water has also been recently developed by the Council for Scientific and Industrial Research (CSIR). The new process reclaims high-quality precipitated calcium carbonate (PCC) from calcium-rich industrial solid waste. PCC is useful for various specialised industrial applications such as gastric-acid treatment, tablet filling in pharmaceuticals, plastics, paint, adhesives and in pulp and papermaking.
According to Dr Mlawule Mashego, the biochemical engineer who developed the technology with Jean Mulopo, they foresee an increase in demand for calcium carbonate for treating acid mine drainage. This research group at the CSIR focuses among others on the development of technologies for the cost-effective production of high-quality effluent from various waste streams. “Some utilities responsible for waste treatment and management are moving away from regulatory compliance towards increased economic incentives in the process of recognising the value of waste and wastewater as a resource. Such an approach includes the recovery of energy, nutrients, metals and other chemicals as part of the wastewater treatment process. We also look at further beneficiation of recovered by-products to enhance waste utilisation,” Mashego says.
There are various initiatives and ideas that could turn mine water and AMD into an opportunity for South Africa. With enough funding, research and development the possibility exists that South Africa’s scarce water resources might still be saved for the next generation.
25° in Africa would like to give full acknowledgement and thanks to Bertus Bierman, Frost & Sullivan, the Water Research Commission and the CSIR, who generously contributed information for this article.