Acid Mine Drainage
Acid mine drainage is the flow, or seepage, of polluted water from old mining areas. Depending on the area, the water may contain toxic heavy metals and radioactive particles. These are dangerous for people’s health, as well as plants and animals.
Acid mine drainage on the Witwatersrand has reached a crisis point. This is because some mining companies allow acid mine water to flow into streams, dams and sources of groundwater.
On the West Rand, toxic water has already destroyed life in the Tweelopiespruit and the Robinson Lake near Randfontein. Even some borehole water is polluted. In some areas the water has polluted the soil, so people cannot grow vegetables. The Tweelopiespruit is part of the Crocodile River system and the Limpopo River catchment area.
According to a report (December 2010) commissioned by the Inter-ministerial Committee on Acid Mine Drainage the mining companies and government have until June 2012 to control acid mine drainage before the toxic water under central Johannesburg begins to flood the tourist mine in Gold Reef City, with estimates of the water reaching the surface – possibly initially in the Boksburg area – in March 2013. On the East Rand, as pumping of water from the Grootvlei mine near Springs stopped in early 2011, estimates suggest that acid mine drainage will flow onto the surface of the ground near Nigel central business district in three or five years – if action is not taken. The Blesbokspruit and the Marievale Bird Sanctuary are are already contaminated with toxic mine water.
The most recent news items for acid mine drainage on this site are given below, for a complete list search on Acid Mine Drainage. Also see this WISE (World Information Service on Energy) website page for a useful digest of news: http://www.wise-uranium.org/udza.html
What can be done about acid mine drainage?
In 2010, civil society groups and the media helped to get the issue of acid mine drainage higher up the political agenda. In response to media pressure, an Inter-Ministerial Committee on Acid Mine Drainage was formed, which commissioned a report by a Team of Experts. The report was made publicly available on 24 February 2011, for a copy of the report, and Earthlife Africa Johannesburg’s review of it, including the Federation for a Sustainable Environment’s detailed response to it, see this link: An action plan for acid mine drainage
For some of the work that Earthlife Africa Johannesburg and other civil society groups have been doing, and for ideas for what individuals can do, see: http://earthlife.org.za/?p=1159
Fact sheets and articles about acid mine drainage
Some useful resources to find out more about acid mine drainage:
ELA (Jhb) fact sheets (pdf) to download:
Federation for a Sustainable Environment: http://www.fse.org.za
Centre for Environmental Rights: www.cer.org.za
‘Legal issues concerning mine closure and social responsibility on the West Rand’, paper in Van Eeden, Liefferink and Durand 2009, paper in The Journal for Transdisciplinary Research in Southern Africa
In 2009, the government produced a plan to clean up certain areas in the West Rand that are polluted with radioactive material. They plan to implement this in March 2010. See the page ‘Wonderfonteinspruit Remediation Action Plan‘ for more information about this and Earthlife Africa Johannesburg’s submission.
An action plan for acid mine drainage
Finally, the seriousness of the acid mine drainage problem in South Africa has been acknowledged at ministerial level and an action plan has been outlined. Mine Water Management in the Witwatersrand Gold Fields with Special Emphasis on Acid Mine Drainage, Team of Experts report to the Inter-ministerial Committee (IMC) on Acid Mine Drainage, December 2010, was made publicly available 24 February 2011. (Acid mine drainage (AMD) is the flow of water polluted with metals and other substances from old mining areas.)
The report basically confirms what civil society organisations, notably the Federation for a Sustainable Environment (FSE), already knew about the situation and have been trying to encourage government to act on for several years.
The high media coverage of acid mine drainage clearly prompted the formation of the IMC and the commissioning of the report, plus the fact that if action is not taken now, toxic mine water will begin to flood the lucrative tourist mine in Gold Reef City, Johannesburg by June 2012.
Earthlife Africa Johannesburg (Jhb) welcomes the IMC report, but it is just a first step. It is over a month since the publication of the report and we have yet to hear news of action plans being implemented. Meanwhile, the acid mine water continues to flow into streams on the West Rand (see ‘Stream destroyed by acid mine water’) and the levels of contaminated water continue to rise below Johannesburg.
Civil society groups vindicated
The various awareness raising and advocacy activities of the FSE, Earthlife Africa Johannesburg (ELA Jhb), the Centre for Environmental Rights and others (for example see ‘Civil society demands action on acid mine drainage’ ) resulted in increased media coverage. It was this, states the Team of Experts report to the IMC (ToE report to IMC), that lead to the issue being considered at cabinet level:
“Recent media reporting has highlighted issues related to acid mine drainage (AMD) in the gold-mining areas of the Witwatersrand. Government has responded to this by forming the IMC to address the issue.” (ToE report to IMC page 85)
The IMC was set up to “Communicate in order to regain and maintain the trust of the people.” (ToE report to IMC page 2)
In 2010 a Department of Water Affairs media release, described civil society groups as “alarmist”. However, the IMC report only confirms what we have been saying about the seriousness and urgency of the acid mine drainage situation.
Acid mine drainage is serious and requires urgent action
The report clearly highlights the dangers of acid mine drainage and cites a range of scientific research undertaken by South African institutions, such as the Council for Geoscience and the Water Research Commission.
“The acidity of the water liberates metals, including toxic metals and radionuclides from the rocks with which it interacts. This may result in acute and chronic toxicity to both human users and the environment, and will generally render water unfit for most uses” (ToE report to IMC, page 21)
On the West Rand, near Krugersdorp the decant (flow onto the surface of the ground) of acid mine drainage “has had a devastating effect on the ecology in the areas immediately downstream of the decant and has degraded streams and groundwater which feed the Cradle of Humankind World Heritage Site.” (ToE report to IMC, page 86)
“Acid mine drainage has significant economic and environmental impacts owing to both the corrosive effects of acid water on infrastructure and equipment, and the severe environmental impacts related to the low pH and high metal and salt loadings.” (ToE report to IMC, page 71)
“The Western, Central and Eastern Basins [the old underground mining areas in the Witwatersrand area around Johannesburg] are identified as priority areas requiring immediate action because of the lack of adequate measures to manage and control the problems related to AMD [acid mine drainage], the urgency of implementing intervention measures before problems become more critical and their proximity to densely populated areas.” (ToE report to IMC page iv)
“One of the pervasive messages regarding AMD from the Witwatersrand Gold Fields is that it has a major impact on South Africa’s major river systems …” (ToE report to IMC page 42)
“The tailings and waste rock generated by mining are significant sources of AMD owing to their interactions with rainwater and surface streams.” (ToE report to IMC page 62)
Acid mine drainage on the Witwatersrand is here to stay
Acid mine drainage occurs in areas where rock containing metal sulphides is exposed to water and oxygen. Due to the topography of the Witwatersrand, even if the underground mining areas are allowed to flood completely there will:
“always be an unsaturated zone above the final water level within the mine voids, covering most of the geographic extent of the basins. This will result in an environment where new AMD is continually produced owing to the interactions between water, air and sulphide minerals” (ToE report to IMC page 22)
A sound knowledge base for taking action exists
The report cites numerous scientific reports, many of which were commissioned by state agencies, that highlight the impact of acid mine drainage on the Western Basin and the potential impacts if the Central and Eastern Basins decant. It also acknowledges that:
“In the opinion of the Team of Experts, sufficient information exists to be able to make informed decisions regarding the origins of the mine water, potential impacts, management strategies, treatment technologies, etc.” (ToE report to IMC page 85)
“… there is a good understanding in the scientific and consulting communities of the requirements for technologically feasible measures that may be taken to reduce the effects of AMD and other mining-related wastes on the environment.” (ToE report to IMC page 10)
Action proposed by the Team of Experts
The report outlines short-term, medium-term and long-term action plans for dealing with acid mine drainage in the Witwatersrand area. It basically recommends:
- Pumping and treating water from the mine voids (the underground mining areas that are filling up with toxic water).
In the Western Basin this action is 8 years too late to prevent the water decanting (flowing onto the surface), but it is hoped that such action will prevent the decant from the Central Basin (predicted for March 2013) and Eastern Basin (predicted for about 2015).
- Earthlife Africa Johannesburg’s concerns: in the short-term only partial treatment by neutralisation is planned, even for the Western Basin which has the most seriously polluted water.
- Neutralisation is basically a process of adding lime to the water which makes the metals fall out of the water to the bottom of the settlement tank. No mention is made about how the resulting toxic sludge, which will contain radioactive elements, will be disposed of.
- Neutralisation does not remove sulphate salts from the water. Therefore, we also recommend that any short-term treatment methods include desalination. The costs of this will have to be borne at some stage anyway.
- Stopping water flowing into the old mine voids, with the aim of reducing the amount of water that has to be treated and pumped over the long term. This includes actions such as canalisation of streams.
- Earthlife Africa Johannesburg’s concerns: the implications of such measures for the ecology of streams and wetland areas, and flood control and management are not mentioned in the report.
- Monitoring mine water, groundwater, surface water, seismicity, subsidence and other geotechnical impacts of mine flooding. This will help to assess changes in water quality and identify additional remedial measures that may be necessary. It recommends setting up a multi-institutional monitoring committee.
- Earthlife Africa Johannesburg’s additional recommendations: The inclusion of long-term biological/ecological monitoring programmes in affected and threatened areas. The inclusion of epidemiological studies and other research into the health impacts related to acid mine drainage. That the results of the monitoring processes are made available to the public in a clear and accessible way. The involvement of local communities in the monitoring process. The participation of respected, credible international bodies in the monitoring process where relevant, such as UNESCO which have an interest in the Cradle of Humankind.
- Monitoring and remediation of other sources of acid mine drainage, such as tailings dams.
- Earthlife Africa Johannesburg’s additional recommendations as per the monitoring of mine water above.
- Investigating an environmental levy on operating mines to cover the cost of treating acid mine drainage from old mines.
- We suggest that consideration should also be given to raising funds internationally from companies that benefited from the gold mining industry.
- An ongoing process of assessment, risk appraisal and recommendations of remedial measures, with adaptation as conditions change.
Addressing the source of acid mine drainage
The priority area for this report was addressing the immediate challenge of preventing further decanting of acid mine drainage on the Witwatersrand. However, it does make reference to the need for better environmental management on the part of mining companies and government regulation to reduce the risks of acid mine drainage.
Inadequate regulation of mining companies
The report acknowledges
“the activities of the mining sector have resulted in serious environmental consequences” (ToE report to IMC page 1)
The report raises serious concerns about the government’s ability to effectively regulate current mining practices. For example it acknowledges that: the regulatory and institutional arrangements for managing acid mine drainage “is a subject area largely neglected by the South African State or State-funded work”. (ToE report to IMC page 10)
This situation urgently needs addressing given the threat to our water resources from acid mine drainage in other areas of South Africa, notably the coal fields of Mpumalanga and the Free State. However, the report falls short of making specific recommendations for this.
Applying the polluter pays principle to old mines
One of the problems related to applying the polluter pays principle of NEMA (the National Environmental Management Act) to mines in the Witwatersrand is the fact that many of the mines have long since closed down. However, the ToE report suggests that more can be done to find the companies responsible for such mines and make the polluters contribute to the clean up. The report states:
“Apportionment studies, performed by the CGS [Council for Geoscience] on behalf of the DMR [Department of Mineral Resources], have found that while a number of the mines in the area are derelict and abandoned, they cannot necessarily be classified as ‘ownerless’. Liability for the impacts of these mines, in terms of Section 46 of the MPRDA [Minerals and Petroleum Resources Development Act 2002], can therefore not be automatically assigned to the State. The apportionment procedure for all basins needs to be verified. Further, an approach to dealing with mining legacies needs to be formulated that will not result in ongoing legal wrangling which could seriously delay the implementation of solutions.” (ToE report to IMC page 12)
The main companies that are still operating in the Witwatersrand area are Mintails, Rand Uranium and Central Rand Gold. Aurora Empowerment Systems has recently ceased operations as it is bankrupt.
On the West Rand: “mining companies allow acid drainage from their surface tailings reclamation operations to flow into abandoned open pits” (ToE report to IMC page 20). This contributes to groundwater pollution and the rising levels of toxic water in the old mining tunnels.
Grootvlei mine: The report states that the Department of Water Affairs was forced to take legal action against this mine, owned by Aurora Empowerment Systems, for failing to keep to the conditions of its water use license. For months the mine pumped millions of litres of water with high sulphate and iron concentrations directly into the Blesbokspruit, which flows through an internationally important wetland (listed as a RAMSAR site).
The Aurora mine stopped pumping acid mine drainage from the Eastern Basin in January 2011 (after the ToE report was compiled). If pumping does not resume, decant is predicted within five years (ToE report to IMC page 25). The water is expected to flow out near Nigel central business district . See: ‘Toxic water floods mine near Springs.
Water pollution from acid mine drainage has severe implications for the future health and livelihoods of people. The threat of this is critical in Mpumalanga where numerous applications for coal mining licenses have been received.
Earthlife Africa recommends that government takes into account the concerns of civil society groups related to the current flaws in the legal system governing mining, especially those related to the process of amending the MPRDA. See: ‘NGOs call for no-go areas for mining‘
A willingness to engage with civil society
So far national government has appeared reluctant to engage with civil society on the issue of acid mine drainage. It is, therefore, encouraging to see stakeholder engagement and public awareness listed in the action plans for the Western, Central, and Eastern Basins. The report also acknowledges that:
“Given the magnitude and dynamics of the South African mining industry, it must be accepted that the challenges of mine water management cannot be administered by either government or the mining sector alone.” (ToE report to IMC page 1)
We hope that this is a reference to greater openness and transparency regarding this issue, and effective participation of civil society in decisions relating to the management of acid mine drainage and rehabilitation of affected areas. Given the reluctance shown so far in applying the polluter pays principle, it may however simply allude to a mechanism for spreading the costs of water treatment.
Some gaps in the report
The ToE report to IMC pays little attention to the health impacts arising from exposure to dust from mine tailings and water contaminated with acid mine drainage. This presumably reflects the lack of epidemiological studies on this. It also does not specifically mention the need for such studies in its summary of recommendations.
One of the metals in acid mine water and mine dumps in the Witwatersrand is uranium. International research suggests that there are long-term health risks related to the chemical toxicity of uranium and radiation from radioactive particles that people may breathe in or swallow. (For example, ECRR Uranium and Health 2010)
The report states that the Tweelopiespruit, near Krugersdorp, a stream that is part of the Crocodile River water catchment area, was in 2000 designated as a class C river (in good ecological condition) but by 2004 it had been downgraded to a class F river (unable to support normal aquatic life) due to acid mine drainage. However, the report fails to mention that Robinson Lake, near the headwaters of the Tweelopiespruit, has been classified by the National Nuclear Regulator as a radiation area. The water in the lake has a concentration of uranium of 16mg per litre – 40 000 times higher than the area’s background levels of uranium in water. This is a direct result of years of mine effluent being pumped into the lake. The bottom of the lake is unlined and aerial photographs indicate that its polluted water has been spreading through the groundwater system.
Why has it taken so long for the government to act on acid mine drainage?
Given the findings of this report it can be concluded that the main reasons for delaying action relate more to issues relating to who will pay for the clean up, political dynamics and the power of the mining industry in South Africa, rather than to a lack of scientific and technical understanding of the issue and water treatment measures.
In addition, the legal framework governing mining allows mining companies to get away without taking their social and environmental responsibilities seriously. The lack of capacity within government to enforce regulations and co-ordinate remediation measures in affected areas also needs to be addressed.
Acid mine drainage and social justice
Like other environmental issues, acid mine drainage is also an issue of social justice. Yet again in South Africa the health and livelihoods of low-income groups have been marginalised. The result of inaction has been the pollution of areas in the West Rand over a period of 8 years (the 2002 Western Basin decant was predicted in 1996). Toxic water and dust from mine dumps threatens the health and livelihoods of thousands of people – many of whom live in informal settlements. (See also: ‘Radiation risks on West Rand‘
The water overflowing onto the West Rand is more toxic, with higher levels of salts and heavy metals, than the water in the other two basins. Yet, despite this since 2002 it has been allowed to flow out, with inadequate treatment processes, at a rate of millions of litres a day.
It took the threat of acid mine drainage from the Central Basin flooding areas of higher economic potential, such as Gold Reef City and central Johannesburg, and so called ‘sensationalised media reports’ to get government to fully acknowledge the problem and take action.
Avoid making the same mistakes
Lessons must be learned from the legacy of gold mining on the Witwatersrand. Scientists predict that the impact of acid mine drainage in the coal mining areas of Mpumalanga and Free State could be devastating. The NEMA principles of the polluter pays and the precautionary approach must be applied when making decisions about mining relative to other land uses.
Stream destroyed by acid mine water
Since 2002, the Tweelopiespruit has been an ‘emergency’ waste pipe for acid mine drainage – toxic water polluted by heavy metals, including uranium, from old mines on the West Rand.
However, unlike in a lined, properly managed slimes dam, water in the Tweelopiespruit cannot be contained. The stream flows through the Krugersdorp Nature Reserve and into a tributary of the Crocodile River, upstream from Hartbeespoort Dam.
Water from the stream is also finding its way towards the Cradle of Humankind (a UNESCO World Heritage Site). It has also polluted borehole water.
In January 2011 the Department of Water Affairs estimated that about 42 million litres (Ml) of mine water was flowing every day into the Tweelopiespruit. Of this only 12 Ml is partially treated by the mining company Rand Uranium. The partial treatment process does not remove the heavy metals from the river system.
As it flows through the Krugersdorp Nature Reserve the stream flows through two dams. The first of these, the Hippo Dam is being used as a settlement pond for the partially treated mine water.
On 3 February 2011 the pH of the water in the Hippo Dam was about 3.5. Just before it flowed out of the Aviary Dam it had a pH of 2 – as acidic as lemon juice (measurements taken by an Earthlife Africa volunteer). In a healthy stream a pH of about 7-8 would be expected. This indicates further problems with the neutralisation treatment process being used, which is currently advocated as a simple and quick solution by the Inter Ministerial Committee on Acid Mine Drainage, see: Ministers catch up with AMD? and Inadequate treatment of acid water flowing into the Tweelopiespruit
The Department of Water Affairs has classified the Tweelopiespruit as a Class V river – a very high acute hazard.
See also: Stream of acid, the Tweelopiespruit