TASK TEAM TO INVESTIGATE
Pretoria – Cabinet is expected to give direction in the next two weeks on how South Africa will deal with the potential crisis posed by acid mine drainage (AMD) in Gauteng.
Environmentalists have described AMD as the single most significant threat to South Africa’s environment and as heavy rains persisted this week, fears grew that the problem may be exacerbated. But the Water Affairs Department on Thursday said a decision was looming on the matter following an Inter-ministerial Committee (IMC) meeting with Cabinet to discuss the situation.
It comes after Cabinet mandated the Minister of Water Affairs, Edna Molewa, in August to urgently establish a special task team to investigate how the government should respond to reports of acid water drainage in some parts of the country, mainly in Johannesburg.
The team of experts, chaired by Mineral Resources Department Director General, Sandile Nogcina, has handed over a list of recommendations to be considered at the next Cabinet meeting before a public announcement can be made.
“What we can say is that government is very concerned and takes this matter very seriously and at this stage the recommendations have been signed by both DGs in the Department of Water and that of Minerals and is ready for Cabinet discussion. Everyone will know the way forward in a week or so,” said spokesperson Mava Scott.
Nogcina was not immediately available for comment but Scott said once President Jacob Zuma and his executive have had an opportunity to look at the document, a public announcement will be made and all the necessary steps will be taken to avert the AMD situation.
Acid mine water, or water contaminated with heavy metals as a result of mining activities, is reportedly affecting the South Africa’s economic hub Gauteng, with other cases in Mpumalanga, North West and Free State provinces. Reports suggest that this drainage poses health and economic risks for the country.
Scientists predict that if drastic steps are not immediately taken to shut down disused mine shafts and pump out the acid mine drainage, the poisonous water will flow into rivers and low-lying areas at a rate of up to 70 megalitres a day.
Sputnik Ratau, spokesperson for the Environmental Affairs Department, said the recent floods, which have raised the levels of the toxic water in the mines, has been a cause for concern.
“We have always said that there are certain periods when the impact will be major due to rains but we are hoping that the next two weeks will provide direction on this matter – but what cabinet decides, is what cabinet decides,” he said.
As a short-term measure, an amount of R218 million was set aside by the department to fit pumps to avert any situation that might arise. – BuaNews
Joburg can be saved from rising acid mine drainage – but only if private and public stakeholders join forces and work fast.
THE government has just 20 months in which to put the infrastructure in place to deal with acid mine drainage in the Witwatersrand area.
The large void beneath the Wits area is filling with water
Acid mine drainage refers to the water that drains over the surface of acid-bearing rock which has been exposed through mining, becoming toxic as it rises to the surface of disused mines and makes contact with air. It threatens the health of rivers and people who come into contact with that water.
The Witwatersrand stretches 50 kilometres from Krugersdorp on the West Rand to Boksburg on the East Rand. Mining started 124 years ago on the Rand, in 1886, but from the 1950s mines across the region started closing down. In 2008, the last remaining operational mine, East Rand Propriety Mines (ERPM) in Boksburg, closed its operations.
ERPM had maintained the water level at 1 200 metres below the surface, pumping 40 million litres of water every day from below ground. The company was in the unfortunate position of having to pump the accumulated water from the remaining disused mines across the Witwatersrand.
Pump water out
While they were operating these mines, mining houses had infrastructure in place to pump the water out. But as the mines closed down and pumping ceased, the underground voids created from mining operations began filling – and continue to fill. Accumulated water flowed into adjacent mines, gradually filling up the entire void.
When ERPM closed, the acid water carried on rising into the void; now, the rising water has covered ERPM’s pump, which is 600 metres below the surface.
The void, created by the removal of 1 300 million tons of rock - yielding over 12 million kilograms of gold - will be completely filled in about two-and-a-half years - just 30 months. But disaster can be avoided if we move quickly.
“The solution to the problem is relatively simple, however, and involves the establishment of pumping stations to pump the water to the surface for basic treatment,” says professor Terence McCarthy, from the school of geosciences at Wits University. He delivered a lecture at Wits last week, entitled “The decanting of acid mine water in the Gauteng city-region”, as part of the Gauteng City-Region Observatory series of lectures.
He indicates that the problem is universal but doesn’t usually occur within a major metropolitan area. McCarthy confirms that at present, the water level is at a depth of about 600 metres below the surface, but it is rising at about 15 metres each month.
“At this rate, the void will be completely filled in about two-and-a-half years from now,” he warns.
The acid water contains sulphuric acid, minerals and metals. “The water that accumulates in the mine void is acidic and contains high concentrations of dissolved sulphate and heavy metals and is toxic and corrosive.”
Decanting water
The acid water will rise and flow out of mines at low points along the reef. These low points are along Main Reef Road and the M2 in Joburg. Already, the void in Krugersdorp has filled up and the contaminated water is flowing out, into streams and watercourses in the area.
Mining companies have closed down, leaving disused mines behind
“Decant will occur because the mine void and openings connected to it such as shafts and collapsed areas occur at a variety of elevations and water will flow into the void in higher areas and decant at low points,” says McCarthy.
The lowest large opening is at the Cinderella Shaft of ERPM in Boksburg, but because water is restricted in its flow laterally, the water level will stabilise at different levels, resulting in multiple decant points.
The first decanting of acid mine water in the city will occur in low basements and the underground cables in Newtown, and possibly also at the disused mine in Gold Reef City, which McCarthy is particularly concerned about as he feels it is a great heritage site, demonstrating to visitors what early mining on the reef looked like.
Solution
But McCarthy says the solution to the problem is relatively simple. It involves establishing two pumping stations – one in Germiston and another in Florida – which will pump the water to the surface, maintaining the water in the void at 250 metres. Treatment plants will need to be established at the pumping stations, and the treated water will be pumped into nearby streams and rivers.
“It must be accepted that pumping will have to continue indefinitely. Initially, this will involve considerable financial outlay to establish the pumping and treatment facilities with an ongoing cost to maintain the pumping and water treatment.”
He explains that much of the expense of the plants will not be new, as the government has for decades been paying pumping subsidies to mines to cover the cost of pumping water from the defunct mines.
But he stresses that time is of the essence, saying there is now a window of opportunity in which steps must be taken to prevent the situation getting out of control. In 20 months, the water will reach the 300m mark, and so “it is essential that steps be taken immediately to start preparing the pumping and treatment infrastructure”.
The Department of Water Affairs has agreed to install one new pumping station and upgrade a sludge treatment operation, to save Johannesburg from rising acid water.
Payment
The question is which parties should pay for the rescue operation – mining houses or the government. McCarthy argues that the government should pay, as it has benefited from tax collected from the companies and their employees. But civil society activists say the companies have benefited from the mining operations and have not acknowledged the damage caused to the environment.
But over the years mining companies have closed down and many no longer exist.
Yet there is good news despite the gloom. In time, probably over 20 years, the quality of the water will gradually improve and become drinkable, making it a profitable operation, says McCarthy.
“However, we have no idea how long this will take and could extend over many decades or longer.”
Read more: http://www.joburg.org.za/index.php?option=com_content&view=article&id=5977&catid=88&Itemid=266#ixzz16ve2NgXA
Johannesburg - Millions of litres of highly acidic mine water is rising up under Johannesburg and, if left unchecked, could spill out into its streets some 18 months from now, Parliament's water affairs portfolio committee heard on Wednesday.
The acid water is currently about 600m below the city's surface, but is rising at a rate of between 0.6 and 0.9m a day, water affairs deputy director water quality management Marius Keet told MPs.
"(It) can have catastrophic consequences for the Johannesburg central business district if not stopped in time. A new pumping station and upgrades to the high-density sludge treatment works are urgently required to stop disaster," he warned.
Speaking at the briefing, activist Mariette Liefferink, from the Federation for a Sustainable Environment, said the rising mine water posed an "enormous threat", which would become worse if remedial actions were further delayed.
"This environmental problem is second (in SA) only to global warming in terms of its impact, and poses a serious risk to the Witwatersrand as a whole. At the rate it is rising, the basin (under Johannesburg) will be fully flooded in about 18 months."
Mine drainage
She said the rising mine water had the same acidity as vinegar or lemon juice, and was a legacy of 120 years of gold mining in the region.
Acid water is formed underground when old shafts and tunnels fill up. The water oxidises with the sulphide mineral iron pyrite, better known as fool's gold. The water then fills the mine and starts decanting into the environment, in a process known as acid mine drainage.
Keet said the problem was not just confined to Johannesburg, which is located atop one of several major mining "basins" in the Witwatersrand, known as the Central Basin.
In 2002, acid mine drainage had started decanting from the Western Basin, located below the Krugersdorp-Randfontein area. The outflow had grown worse earlier this year after heavy rains, prompting his department to intervene.
However, a lack of treatment capacity in the area "compelled in-stream treatment as a short-term intervention".
This intervention saw the department pouring tons of lime, an alkali, into the Tweelopies Spruit in an effort to neutralise the acid mine water. This had led to problems with the resulting sludge that had formed in the water course.
The region's Eastern Basin, below the town of Nigel, was also threatened. The last working mine still pumping out water in the area was Grootvlei. Keet said that if the mine stopped pumping, acid water would start decanting into the town "within two to three years".
Legal action
Water Affairs is currently taking legal action against the mine, after it allegedly failed to comply with a departmental directive to treat the pumped water before discharging it.
On stopping the growing threat below Johannesburg, Keet said about R220m was needed to establish pump stations, pipelines and treatment works. Responding to a question, he said there were plans to tackle the problem.
"The idea is to build a pump station; the challenge is where the money will come from," he said.
Liefferink said if the acid mine water rose to the surface in Johannesburg's CBD, it posed a threat to the city's inhabitants, its buildings and the surrounding environment.
She told MPs that residents of many of Gauteng's poorer communities were living alongside, and in some cases on top of, land contaminated by mining activities. They were exposed to high concentrations of cobalt, zinc, arsenic, and cadmium, all known carcinogens, as well as high levels of radioactive uranium.
"In some cases, RDP houses are being erected next to radioactive dumps," she told MPs, who expressed shock and concern at the news.
Liefferink said acid mine drainage was exacerbating the problem, because it dissolved the heavy metals and precipitated them in water sources and wetlands, where people grew crops and abstracted water.
Threat
She also warned that some of the heavily polluted streams drained into the Vaal River system, and posed a threat to the region's water supply.
Liefferink, who backed up her presentation with a series of photographs showing, among other things, shacks erected on top of an old mine tailings dump, received a round of applause from MPs.
Mining started on the Witwatersrand about 120 years ago. More than 43 000 tons of gold and 73 000 tons of uranium have been extracted from the region's mines.
According to Liefferink, this mining activity has left a legacy of about 400km² of mine tailings dams and about six billion tons of pyrite tailings containing low-grade uranium.
"Waste from gold mines constitutes the largest single source of waste and pollution in South Africa... Acid mine drainage may continue for many years after mines are closed and tailings dams decommissioned," she said.
- SAPA
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