Water affairs vows to tackle acid mine drainage
Mining companies and the Department of Water Affairs—part of a government task team on mine closure and water management—have agreed to cooperate to fight acid mine drainage, the department said on Thursday.
Acid mine drainage was affecting the Western, Central and Eastern Basins (the Witwatersrand gold fields area) and this had negatively effected the Vaal and the Crocodile River systems, the department said.
“Following a series of consultative meetings the parties agreed on cooperation, in the form of a partnership between government and the mining houses so as to formulate a collaborative solution to the acid mine drainage problem,” the department said in a statement.
The parties agreed that the model would consist of mine-water collection and conveyance to a central point. It would include the development of new infrastructure and refurbishment of existing infrastructure to collect and treat mine water.
There would also be treatment of the mine water to address low pH, high levels of metals and salinity while the re-use of treated mine water would be encouraged.
The model provides for the establishment of a public-private partnership and the setting up of a non-profit making entity.
“The entity will assume the technical and operational responsibility for executing the technical solution to acid mine drainage in the Witwatersrand area.”
Urgent action needed
A contract between government and the mining houses would be signed and the funding of the entity would as far as possible be apportioned between the parties.
The department acknowledged the seriousness of the threat posed by acid mine drainage to the environment and it said it was “mindful of the urgency with which the matter has to be addressed”.
Once the proposed model had been signed-off by all parties, the feasibility study would commence.
The department said in the meantime, interim measures would be implemented to control decanting from the Western Basin and the anticipated decant from the Central basin.
These measures include maximising the pumping and treatment at existing facilities in the Western basin and the use of temporary storage facilities to contain any overflows.
Acid mine drainage occurs when sulphate bearing minerals are exposed to oxygen.
The process, termed pyrite oxidation, is enhanced when water moves through and over the surfaces of acid bearing rock exposed through mining activities which disturb the underlying geology.
According to the department, the issue of acid mine drainage was further complicated by the fact that some of the mines in the affected area were no longer operational or ownerless, making it difficult to enforce compliance.
“This requires that the state takes liability in the interest of the public, especially when the matter has to be dealt with as a matter of urgency,” it said. - Sapa