Rising waters, mounting fears, flow from South Africa's mining legacyPublished by MAC on 2010-11-29
Source: Mail & Guardian (2010-11-12)
Acid Rock-Acid Mine Drainage (ARD-AMD) has long been recognised as the worst - if not the most intractable - technical outcome of ill-managed and inadequately closed metallic mines.
According to the first article below: "The United States Environmental Protection Agency considers AMD to be one of the world's biggest environmental threats, second only to climate change".
Over the past decade, attention has increasingly been drawn to this "problem" as it impacts on South Africa's Witwatersrand - "the world's largest deposit of gold and host to mining operations for more than 120 years ".
More recently, this area has become a living (or dying) laboratory for several studies of how to prevent acidic waters engulfing the city of Johannesburg itself. See: London Calling proffers a history lesson on South Africa's toxic tailings
Yet, it's clear that - even as the deadly waters rise, threatening the very "Cradle of Humankind" itself - the experts themselves can't agree on how to forestall looming disaster.
To date, there is no scientific consensus on appropriate remediation strategies, which can be simply summarised as "whether to pump or not to pump".
According to one argument, if the mines are allowed to fill up entirely with water, then the AMD will disappear by excluding oxygen from the system.
But some scientists urge that the waters be pumped out, thus keeping their levels at 400 metres below the surface.
Others assert that this would only intensify acid mine drainage. In any event, such a "solution" would require pumping in perpetuity.
The fatal Fal
Many Cornish inhabitants are bitterly aware of what may happen if the process of controlling acidic waters from mine shafts is abruptly terminated.
During four years from 1988, Rio Tinto kept crucial pumps running at the closed-down, but flooded, Wheal Jane tin mine in the southwest of England.
The company and the government then withdrew their funding, and the pumps were switched off by the independent management.
The consequence was the biggest toxic tailings disaster in British post-war history.
One January night in 1992, twelve million gallons, laced with arsenic, zinc, cadmium and mercury, surged up the shafts, burst over the tailings dam, plunged into a nearby creek, and smothered the Fal river and its estuary.
Precious offshore oyster beds were completely smothered, and this major river literally ran red for many weeks. See: London Calling - September 27 2002
The livelihoods of local fisherpeople and farmers were profoundly affected by the event; fortunately it didn't substantially impact on Falmouth town and nearby human settlements.
Nonetheless, acid waters continued flowing into the creek for many years.
South Africans now face a similar disaster - but one that would make the Cornish mishap pale almost into insignificance.
[Commentary by Nostromo Research, with thanks to Mark Muller, 27 November 2010].
Rising water, rising fear: SA's mining legacy
By Mara Kardas-Nelson
Mail & Guardian (South Africa)
12 November 2010
Environmental activist Mariette Liefferink's four-inch crimson heels still sport their Woolworths sticker as they puncture the sulphuric crust lining Robinson Lake, situated in the Western Basin of the Witwatersrand.
The water is quiet, smells slightly of vinegar and laps gently against a shore devoid of any life save for a few, lone reeds. Behind the lake is a large, naked yellow mountain of mine waste adorned with a few small green nets meant to stop the dust from blowing in an incessant wind.
Liefferink talks sweetly over her asthma. "This lake has a pH of two," she said. "It's pure acid, coming from flooding mine operations just up the road. There are no life forms here. It's completely dead."
This is acid mine drainage, or AMD, a problem so complex, overwhelming and shrouded in economic, political and scientific machinations that it has become a terrifying yet poorly understood criminal.
South Africans are fearful that Johannesburg may soon be at the mercy of acid water, with whisperings of the CBD crumbling as basements flood and buildings corrode.
The government is said to be too slow, gutless and corrupt to enforce necessary action, the mining companies too heartless and unwilling to pay, the community and environmental activists too alarmist and the solutions too expensive or ineffective.
In reality, these statements represent a wide variety of fact and fiction. AMD involves an elusive and complicated mass of overlapping, incorrect or incomplete data, personal politicking marked by oft-interchanging vendettas and alliances and an environment pockmarked with racial prejudices, the unpredictable demands of the international market, foreign exploitation, and a broken political, legal and managerial landscape fuelled by apartheid and encouraged under the democratic government.
This is not just about water. And nothing is as it seems.
What is AMD?
Acid mine drainage is a side effect of mining operations the world over. It occurs through natural runoff after rains flush through a mine dump; from mine companies disposing of the water used in their operations; or from old, disused mine shafts filling up with water, eventually decanting, or flooding, above ground.
The United States Environmental Protection Agency considers AMD to be one of the world's biggest environmental threats, second only to climate change.
AMD is high in sulphates (salts) and heavy metals and bears a low pH, the marker of acidity.
This toxic mix means that the water cannot be used for human or animal consumption, because exposure to uranium and other heavy metals can result in toxic and radioactive effects such as cancers, mental disorders, birth defects and kidney failure.
AMD also has a negative impact on the environment, severely affecting the ability of plants to grow and animals to thrive.
The Witwatersrand, home to the world's largest deposit of gold and host to mining operations for more than 120 years, saw its first decant when the Western Basin overflowed with acid water in 2002, with acidic water rushing through a Rand Uranium operation and into Robinson Lake. Because of its high uranium content the lake has been designated a hazardous radiation site by the National Nuclear Regulator.
AMD is soon expected to decant in the province's Central and Eastern Basins and can be found already in Mpumalanga, North West, KwaZulu-Natal and the Free State. And it's not going away anytime soon. Because of the large number of mine dumps and huge, empty and largely uncared for voids, or empty underground basins, experts predict that today's mine waste could create AMD for hundreds to thousands of years to come.
On top of that, South Africa's unique geology actually encourages the country's extensive AMD problem. The Witwatersrand was named for its luscious, flowing white waters. But its underground basins were drained of water through pumping, a process termed "dewatering", so that gold deposits could be extracted from ever-greater depths. This process resulted in the creation of massive voids.
But as the rand's deposits became scarcer, companies ceased pumping activities and closed up shop. The now-empty basins began filling with water, collecting along the way salts, iron pyrite - also known as Fool's Gold, which, when oxidised, becomes acidic -- and heavy metals. Now those fountains are producing water again, said Liefferink. But this time it won't be white, clean water, but AMD that's coming above ground.
What's at risk?
With the Western Basin still decanting at a rate of between 15-million and 30-million litres a day and 56-million litres during heavy rains, the Central Basin, on which Johannesburg lies, is predicted to produce 60-million litres a day within a matter of months. This is equivalent to water from 24 Olympic pools hitting the city's streets daily.
In July the department of water affairs stated that potential decant within the Johannesburg area could take place within 18 months, or by early 2012. The water is now estimated to be 530m below the surface and rising at a rate of between 0.3m and 0.9m a day. This rate could increase with heavy summer rains.
Large buildings in the CBD, such as Standard Bank and Absa, have been listed by activists and scientists as potential targets and Gold Reef City is expected to be one of the first major attractions to end up under water.
Standard Bank and Absa have commissioned studies to look at potential effects but the results have not been publicly released. The Council for Scientific and Industrial Research (CSIR) said Gauteng has the potential to create 350-million litres a day of AMD decant by 2014, the equivalent of 140 Olympic swimming pools.
The department of water affairs suggested building a pumping station to keep the decant at bay, but work on this has yet to begin.
In late October farmers warned that the water could affect exports to European markets, with Spar and Pick n Pay expressing concern over the safety of their produce.
The Cradle of Humankind, a world heritage site, is a potential target, with the Western Basin decant making its way through the Krugersdorp Nature Reserve's hippo pool and into the Cradle area. Garfield Krige, a mine consultant who predicted the 2002 decant, said that "for every megalitre of mine water, about 300 litres of void is created. Sooner or later we're going to get major collapses in the Cradle."
On the record for decades
Communities, scientists, mining companies and government have known about the AMD threat for decades.
Before mines were given permission by government to dewater their voids in the 1960s, a 1957 document presented by the Chamber of Mines to the CSIR noted potential problems with what it termed "re-watering", or decant, after mines closed, with both processes potentially and actually producing sinkholes, increasing seismic activity and causing water and air quality to deteriorate.
As Witwatersrand gold operations began to close en masse in the 1990s, studies were done to ascertain the potential impact of ceased pumping. In 1996 Krige was involved in producing what became known as the Strategic Water Management Plan, or the Swamp report, which predicted within a month of accuracy that AMD would make its way to the Western Basin surface in 2002.
"The [department of water affairs] was completely aware that the voids would start filling up," said Krige. "The fact that the department [did not] take proper decisions over that period, from 1996 to now ... [gave] all the mines time to get rid of their liability ... The department should have said 2002 is the deadline. [Instead], in 2002, the water started to decant and it caught everybody off guard, even though everybody knew about the whole thing. It's now 2010 and nothing has been done."
Internal government discussions have noted concern over Central Basin decant for years.
A 2009 water affairs department memo considered AMD "the single biggest environmental threat that this Government and country will be faced within the immediate future if the necessary managerial decisions are not taken timeously ... The rise in the water table will have catastrophic consequences if not dealt with timeously."
While AMD has been known about for decades, little money has been made available either by government or industry to remedy decant and mitigate disaster.
Issues surrounding liability are central to who will pay, with many of the major players that operated throughout the Witwatersrand's 120-year history having packed up and moved on, leaving smaller, less economically successful mines to pump and treat water they did not contaminate.
Nationwide, there are nearly 6 000 ownerless or abandoned mines, according to the department of mineral resources, most of which have not undergone proper remediation.
"Establishing liability is a very complex problem," said Democratic Alliance MP Gareth Morgan. "The vast majority of mines that are responsible for the decant have ceased to exist or have been abandoned and have not been rehabilitated."
The 1970 Fanie Botha Accord stated that mines that closed before 1956 are the responsibility of government, with those that closed afterwards to be remediated by the responsible company.
While, in theory, regulatory laws and bodies have been enhanced post-1994, in practice a large brain drain from the public to the private sector enabled by lack of funding and poor management has resulted in these laws rarely being enforced.
Carin Bosman, former director of water resource protection and waste at the water affairs department, said that without adequate funding officials are virtually helpless. "You can issue the directive, but then you don't have the money to back it up.
The costs often trump what is allowed within the budget."
Infighting between departments and overlapping laws and bodies make it difficult to know in which cases legislation should be instigated and when one rule takes precedence over another.
Said Paul Marden of trade union Solidarity: "The department of mineral resources is involved, [the department of] water affairs is involved, [the department of] tourism is involved and you often find that people sit and pass the buck to each other. Each department wants to maintain its own independence and then you don't get anything done."
The task team
The recently appointed inter-ministerial task team on AMD, announced in September by the former water minister, Buyelwa Sonjica, and consisting in part of experts from the CSIR, the Water Research Council, the Council for Geosciences, the Chamber of Mines, the mineral resources and the water affairs departments, may denote a change in governmental behaviour.
In late October government announced that the water affairs department would report the team's findings to Cabinet by mid-December. While activists and experts are hopeful, the team's work has been kept from the public domain.
An October 15 report released by the team was not made public. Instead, a four-paragraph press statement was released. When a tender for pumping and treatment options was announced and then immediately revoked, government would not respond to queries from lawyers, activists or treatment companies about why this happened.
Marius Keet, a member of the team and a water affairs official, said that no comment could be made while the group was still in "sensitive" discussions. The DMR also refused comment, after over a month of repeated requests from the Mail & Guardian.
Liefferink contends that the lack of information stemming from the task team is indicative of a general government trend.
While AMD "is not a unique South African problem, what is unique ... is that it is denied, it is suppressed, it minimised ... and not addressed," she said. "We're living in an autocracy and not a democracy. Government is meant to engage civil society in these discussions and instead we just see ... suppression of facts."
Within the world of AMD, nothing is clear, transparent, or easy to understand. Nothing save for the white sulphuric crust lining Robinson Lake and popping up across South Africa's mining lands.
This project was made possible by funding from the Open Society Foundation for South Africa's Media Fellowship Programme
To decant, or not to decant? That is the question
By Mara Kardas-Nelson
Mail & Guardian (South Africa)
11 November 2010
Concerns that Johannesburg and the Cradle of Humankind will soon be flooded with acid mine drainage (AMD) have been central to discussions on polluted mine water for months, with the public being worked up into a frenzy about the CBD sinking and South Africa's heritage being wiped out.
While a media storm has been created around these predictions, fuelled by worried activists and a reactionary government, estimations of both sites flooding are not as concrete as one might think. Some scientists and government officials note that Johannesburg will with no uncertainty be the next target, advocating action, while others claim the city faces a very minimal threat. Similar opinions surround potential affects on the Cradle.
So, who's right?
The answer lies in a muddled pool of conflicting data. No one disagrees that both sites have been or will be affected in some way, but to what extent remains heavily debated.
Polluted water is indeed rising within Gauteng's Central Basin, which houses Johannesburg. It is currently 530m below the surface, increasing between 0,3 and 0,9m a day. While the Department of Water Affairs (DWA) originally estimated that water would hit the Jo'burg streets in early 2012, the current interministerial task team has reportedly pushed that date back on AMD to 2014.
The DWA has pegged the so-called environmentally critical level at 400m below the surface. That means that if the water rises above this, groundwater will be affected, decant inevitable, and the effects exponentially worse than if the water is kept at bay. Speaking to Agence France-Presse in July, the department's Marius Keet promised that pumping would take place so that "[AMD] will not decant in the city of Johannesburg".
According Gerrit van Tonder of the Institute for Groundwater Studies (IGS) at the University of the Free State, the suggestion to pump at 400m is based on "a wrong conceptual model used by [the Council for Geoscience (CGS)] ... the seriousness of the acidic mine water decanting at 57 mL [or 57-million litres] a day close to Boksburg is by far exaggerated and so are estimations about the poor quality of the water that will decant. I'm not saying it's not going to [happen], but it's not going to decant in February 2012. And it will be manageable."
The IGS estimates that water will not reach the surface until June 2014 at the earliest.
Pumping could in fact worsen the situation, said Van Tonder. "Pumping at a fixed level of 400m below Boksburg will create, (a) mixing, (b) water turbulence, (c) structural erosion and also (d) seismic activities," he explained. Pumping could "most probably cause serious earthquakes in the Central Rand ... All of this poses a problem much more serious than the supposed decanting of acid water."
Rather than removing water from the filling void, "you must get rid of the oxygen, and the way to get rid of oxygen is to fill up the mine", says van Tonder. Iron pyrite mixing with oxygen is a crucial part of the creation of acid mine drainage.
The institute noted that those who are in favour of pumping at 400m are "mostly non-hydro geologists", such as government officials, academics specialising in other fields, and activists, while those against the pumping are "mostly hydro geologists".
Van Tonder says that DWA and individual members of the task team have refused repeated requests to meet with the IGS.
Earthquakes have been sited as a potential impact of the basin filling, shaking building structures. According to mine consultant Garfield Krige, who predicted Gauteng's 2002 Western Basin decant, "it's known that when you fill up a basin, or anything that contains water ... there may be several nasty earthquakes because you're putting pressure on rocks that weren't under pressure".
"You will have earthquakes, but it's not comparable to [those] along a fault line," he continues. "In all likelihood it's going to be similar to the mining related tremors we used to have."
Additionally, Krige says, "there is theoretically a chance that the foundations of buildings could impacted, but it's not going to happen overnight. It's going to take tens, maybe hundreds of years".
Lesley Stoch of the North-West University at Potchefstroom was commissioned by Absa and Standard Bank to assess whether reports of their CBD buildings being affected were correct. According to his research, neither site is threatened. "The Central Basin is level, like a lake. Water will come out at the lowest point, which is not in the CBD," he says. "It might affect properties in the south of the city, which are lower ... but definitely not the CBD."
Where the decant occurs is of significant concern. According to Krige, "it's going to decant in the Klip River catchment, so the drainage is going to be towards the Vaal River, and the water will enter the Vaal Barrage dam." The Klip runs through Soweto, home to 1,3-million people, while 10-million users pull from the Vaal dam daily. Because of this, Central Basin decant "is going to be even more significant than the Western Basin," says Krige.
Figuring out exactly what will happen, and where it will happen, is made difficult by a lack of transparency and access to data, according to Frank Winde of North-West University at Potchefstroom. While the Department of Mineral Resources began looking at re-filling of empty voids years ago, this data is "currently embargoed by the [CSG], labeling the unfinished project "work in progress". That may put the CGS in an advantageous position for the current DWA tender on the issue. I also agree with Trevor Manuel that there are private interests at play in sensationalising the issue." In August, Manuel was quoted as saying that "private-sector interests" were driving debate on AMD, particularly in Johannesburg, and that a "rational debate" was needed to properly assess the situation, adding "the idea that there will be acid mine drainage running through the streets of Johannesburg next week, and that we should all walk around in gum boots, is completely ridiculous."
AMD in the Cradle: The devil is in the dolomite
Just as there are a flurry of questions over whether, when, and how Johannesburg will be affected by acid mine drainage , scientists are sparring regarding the Cradle of Humankind. While there is no denying that polluted mine water originating from the Western Basin decant has made its way into the World Heritage site, whether the caves have already been affected -- and to what extent they may be in the future -- is up for debate.
The large amount of dolomite housed within the Cradle is central to differing opinions. Dolomite is a type of rock commonly found across South Africa, and specifically Gauteng. "Dolomite is calcium carbonate, basically. It's easily soluble, and also holds huge volumes of water," explained Carin Bosman, former director of Water Resource Protection and Waste at the Department of Water Affairs and Forestry. While dolomite already dissolves easily, "the acid dissolves [it] much faster."
Phil Hobbs of the Council for Scientific and Industrial Research, who has been assessing groundwater quality in the Cradle for over a year, noted that "acid mine drainage is only one of the threats to the area ... One of the other, bigger threats is treated waste water effluent out of the municipal waste water works."
Ironically, the mix of sewage water and acid mine drainage may in fact have a positive effect. Because of dilution, "to a certain extent the municipal waste water is helping to mitigate the impact of the ... mine water," Hobbs explained. In addition to the dilution effect, "nutrients [from the sewage] capture the metals [from AMD]... [these metals] help to coat and armour the dolomitic strata, in other words helping to protect it from further dilution, meaning that less dolomite will be dissolved."
Based on his data, "for the majority of the fossil sites [of which there are 14], there are only five that have a risk rating of moderate or higher ... most are all low to very low," Hobbs says. "One can never say never, but it is extremely unlikely that [the north and north east part of the Cradle] will ever be threatened by any source, be it AMD, be it anything else."
Krige notes that due to the large amount of limestone within dolomite, the rock helps to neutralise the water by raising the pH. But while that's "obviously a good thing because it purifies the water, just because it isn't polluted doesn't mean [the Cradle's] not impacted. For every mL of mine water that hits dolomite, about 300 litres of void is created...a lot of this...could be under the N14 road [connecting Pretoria to Springs]. There is a danger that this could collapse."
For Francois Durand of the University of Johannesburg, studying amphipods, or blind shrimp who live in the Cradle, demonstrates the effect of AMD on the natural environment. "As you approach the mines from the Cradle, the composition and the quantity of the insects in the water becomes impoverished," he says. "There are less and less and fewer and fewer, until you get to Robinson Lake [in the West Rand] where it's devoid of life."
Amphipods aren't the only organisms at risk. "If the surface water is compromised, the bats will die, and that will have an effect in the [cave] ecosystem as well, and things above ground will die," says Durand. "If both the ground and surface water are affected, the entire ecosystem will collapse." Amphipods also act as a key food source. "[Insects] that live on the banks of the rivers, actually take up heavy metals, so it is made accessible to the rest of the food web."
Amphipods are "endemic to Gauteng and Limpopo," he continues. "You don't get them anywhere else. If they disappear here, they disappear off the face of the earth."
While Durand says that the Cradle has not been heavily affected impacted yet, he suggests that the worse-case scenario must be protected against, given the importance of the site to South Africa's tourism industry and heritage. "I am a socialist ... with respect to our heritage. It belongs to everybody equally," he says, noting, "this isn't just South African heritage, this is world heritage."
This article made possible through funding from the Open Society Foundation for South Africa's Media Fellowship Programme