JOHANNESBURG (miningweekly.com) – The South African Cabinet has approved the recommendations made by a team of experts on the acid mine drainage (AMD) situation in the Witwatersrand, spokesperson Jimmy Manyi said on Tuesday.

The report, which includes recommendations on control measures to reduce the rate of flooding and the eventual decanting and pumping volume, would be made publicly available on Thursday.

Finance Minister Pravin Gordhan is expected to announce financing for AMD solutions in his Budget speech on Wednesday.

Funds from the government were already available to deal with the situation in the Western basin, where the decanting of acidic water to the surface was already taking place, while a pump station to deal with rising water in the Central basin would need to be in place by March 2012. This would be to ensure that AMD did not rise above the 200 m level in the Central basin.

Manyi also noted that Cabinet had agreed that further work would need to be done to investigate the possibility of an environmental levy for consideration by Cabinet.

National Planning Commission Minister Trevor Manuel said that the issue of an environmental levy was a complex one, especially considering that in Emalahleni in Mpumalanga certain coal mining companies were already paying for the treatment of acid mine water.

He emphasised that the AMD was a shared responsibility, and government would look to reclaim funds from profit making mines to assist in dealing with the issue.

Manuel stated that further studies would need to be done into mines that were still operational in the area, those which have only recently stopped operating, and those that have long since been derelict and ownerless.

Some of the recommendations from the team of experts that were stated were: implementing ingress control measures to reduce the rate of flooding and the eventual decanting and pumping volume; reducing costs to deal with AMD; improving water quality management including neutralisation and metal removal in the short-term; removal of salt loads from river systems to be considered in the medium to long term; and improving monitoring and undertaking research to inform decision making and managing and monitoring other AMD sources within the Witwatersrand basin.

BASIN BY BASIN

Manuel emphasised that there was “no need for panic” on the matter of AMD, and was confident that the scientists on the panel of experts had given sound recommendations.

He stressed that there was a need to distinguish between the three separate basins in the Witwatersrand, namely the Eastern basin, the Central basin and the Western basin, where mining operations had taken place at different depths and the rate of rise of underground water was different.

The situation in the Eastern basin was said to be under control, where the AMD was some 700 m below the surface.

There was also no pumping taking place in the Central basin, where the AMD was sitting at about 500 m below surface. However, it was envisaged that water in the Central basin would reach the surface by June 2012, thus work on designs for a pump station would need to start immediately.

The Western basin, below the Krugersdorp area, was where immediate action would need to take place, as AMD has been decanting onto the surface since 2002, and the rate of decant was exacerbated by heavy summer rainfall.

Manuel said that there was already work taking place on the Western basin, and canals were being constructed in Florida to ensure that water did not get into the mine shafts.

Department of Water Affairs (DWA) acting director water quality management for Gauteng Marius Keet said that AMD was decanting at a rate of 50 Ml/day in the Western basin. Of this, some 12,5 Ml/day was being treated by Rand Uranium − a miner, which operates in the Western basin.

The water that is treated undergoes lime neutralisation, and the heavy minerals are removed. Some of the remaining water, which is decanting but is not being treated, moves through a wetland, acted as a filter, removing some of the heavy metals.

This partially treated water runs into the Tweelopiesspruit, which flows through the Krugersdorp Game Reserve.

Keet said that the game were not drinking the acidic water because the mines operating in the area had drilled a borehole to provide safe water for the animals.

There were also two communities and a business in the area that could potentially be affected, however these people were being supplied with drinking water from Rand Water, through the mines.

Talks between the government and the mining industry were ongoing, and the DWA said that co-operation was going well but would have to be taken further.

The costs of dealing with AMD, and how these costs would be met were not detailed, and were said to be dependent on the methodology and technology chosen to deal with the problem.

While the DWA would be managing the process of monitoring water levels in the basins, the Department of Mineral Resources was also said to be playing a fundamental role in dealing with the issue.