The Department of Water Affairs (DWA) on Thursday released the long-awaited 146-page acid mine drainage (AMD) report, which was compiled by a team of water and geology experts, and presented to the Inter-Ministerial Committee on AMD in December.

After assessing the situation in the Witwatersrand area, the experts recommended that AMD intervention and management measures be undertaken “as a matter of urgency” to “avert impending crises and stabilise the situation”.

Contamination of shallow groundwater resources required for agricultural use and human consumption, geotechnical impacts, such as the flooding of underground infrastructure in areas where water rises close to urban areas, and increased seismic activity, were some of the risks identified in the report.

A generic approach to the risks was put forward for the priority areas, namely the Western, Central and Eastern basins.

Cabinet approved the report at its meeting last week, and on Wednesday, Finance Minister Pravin Gordhan announced that R225-million had been set aside for dealing with AMD.

Independent environmental adviser Anthony Turton described the report as a good one and he commended the acceptance of the science by political leaders, which would go a long way to re-establish investor confidence.

“The report also makes it clear that given the complexity, we will have to learn as we go along. This is a good approach because it moves away from the one size fits all,” he added.

In the Western basin, intervention would require the establishment of a neutralisation plant with a capacity of 20-million litres a day, to supplement the existing treatment capacity operated by Rand Uranium. An upgrade of mine water pumping facilities would also be required.

In the Central basin, a pumping facility with a capacity of about 60-million litres a day would need to be installed in one or more of the existing mine shafts, and a neutralisation plant or plants of matching capacity, would need to be established nearby.

Expanding on the problem in the Central basin, which is the largest, the report said that the water level has been rising at an average daily rate of 0,59-million litres since July 2009, varying seasonally between 0,3-million litres a day and 0,9-million litres a day. By the end of November, the mine water level reached an elevation of  about 1 155 m above mean sea level, measured in Catlin shaft at Simmer & Jack Mine. This was 510 m below the surface at this location.

It was predicted that the rising water level would reach the surface by March 2013.

“By this time, it will have sterilised still exploitable gold reserves located at a depth of less than 400 m below the surface. Of even greater consequence is that it will not only have flooded the shallower underground tourist facilities at Gold Reef City, but also compromised the shallow groundwater resource associated with the dolomitic strata located to the southeast of Johannesburg,” said the experts.

In the Eastern basin, the pumping capability in number 3 shaft of Grootvlei mine had to be secured. The report also stated that the existing treatment plant had to be returned to service “as soon as possible”.

It was also noted that the volumes of water to be managed could be reduced by the timely implementation of ingress management measures, with a subsequent reduction in operating costs. The design of the pump and treatment systems would need to take this into account.

The report also highlighted international experience in the management of AMD problems, and compared these with the South African situation and explored the possible involvement of the private sector.

Risks identified owing to decant were serious negative ecological impacts on the receiving environments, and local and regional impacts on the Vaal and Crocodile river systems that could affect fitness-for-use of the receiving water resources to downstream water users.

“AMD will aggravate an already upward trend associated with salinisation of the receiving river systems, necessitating additional dilution releases to be made and subsequently risking water supply security within the integrated Vaal river system,” added the experts.

The experts recommended that the process of assessment, risk appraisal and remedial measures be continued as the problems posed by AMD would have implications far into the future. “The process of management of these impacts will therefore need to continue, with ongoing assessments and adaptation as conditions change,” the report said.

Turton said that it was “good news” that no consideration was being given to the ‘treatment’ of the mine water effluent to potable standards. “This was always my major concern with past planning, because I had a moral dilemma about cleaning up hazardous waste using the lowest-cost technology and then selling it to people for drinking purposes. This does not mean that potable water cannot result - we know it can from the eMalahleni case - but then it comes from world-class technology, and not technology that has been selected merely because it is the least cost option.”

In a nutshell, the approach was to stabilise the hot spots as a first step towards finding a longer-term solution. This would involve the pumping and basic treatment of water in the Western and Central basins, with a view to re-establishing the status quo during active mining. This water would be neutralised only, which meant that sulphates would not be removed.

The neutralisation creates a precipitate that is high in iron and other heavy metals. It was not clear what would be done with these, but Turton noted that indications were that they would be discharged to existing tailings dams as a short-term measure.

“Significantly, this approach moves away from the centralised planning envisaged by Western Utilities Corporation. This means that the proposed approach is now consistent with international best practice about the treatment of different waste streams at source rather than mixing them. This is obviously a good thing because it places South Africa at the forefront of international best practice once again,” Turton stated.

He added that the high sulphates would still mean that receiving water quality was an issue, and dilution in the Vaal system would still have to occur. “This will bring on Phase 2 of the Lesotho Highlands Project, which will add cost to the consumer. Sadly this will also use future options today, which means that South Africa is running out of options and will have to become very creative if it is to grow the economy and create full employment consistent with the New Growth Path.”

Turton said that the second phase, which would be about sulphate removal, would become an opportunity for new technologies to come forward. These would include desalination, ion exchange and crystalization among others.

“This is good news for the engineering sector and is likely to create jobs and opportunities,” he reiterated.

The situation in other mining regions of the country was said to require additional information, monitoring and assessments of risk, particularly in vulnerable areas such as the Mpumalanga coal fields, where the impact of mining on the freshwater sources in the upper reaches of the Vaal and Olifants river systems was of serious concern.

AMD has also been reported in other areas in South Africa, including the KwaZulu-Natal coal fields and the O’Kiep copper district.