Overview of acid mine drainage impacts in the West Rand Goldfield

1. Overview of acid mine drainage impacts in the West Rand Goldfield Presentation to the Director General of DWAF: 2 February 2009

7. Pre mining situation Before mining, the water table will have followed a natural piezometric surface Springs may have developed in areas where this surface lies above ground level and where suitable conduits exist by which water can flow to surface

8. During active mining phase During mining, dewatering will have lowered the water table within the mine and surrounding areas Springs will have dried up in the area affected by dewatering

9. Post mining situation Water will tend to return to the pre-mining piezometric surface, although this is likely to be flat (or flatter) due to the higher transmissivity of the mined out voids Water will decant from mine openings or other conduits where these lie below the piezometric surface

10. Downstream groundwater pollution Polluted water discharged to the Tweelopie Spruit recharges the Zwartkrans Compartment, leading to contamination of substantial karst groundwater resources and as yet poorly determined impacts on the Cradle of Humankind World Heritage Site

11. Water pollution management via maintenance of water levels at the ECL This situation may be managed via maintenance of water levels at the Environmental Critical Level (ECL), defined as that level where contaminated mine water will not impact on the environment. The ECL for surface water has been identified for the West Rand only. Additional groundwater investigations are required to determine the appropriate level for groundwater protection however it is estimated to be 100-150m below the surface water ECL level. ECLs have not been determined precisely for the other goldfields although there is a good conceptual understanding of issues, particularly in the Central Rand.

12. pH(Water discharged to the Krugersdorp Game Reserve)

13. Electrical Conductivity(Water discharged to the Krugersdorp Game Reserve)

14. Events: January-March 2008

15. Downstream groundwater quality(Krugersdorp Brickworks Borehole)

16. Volumes and loads Polluted water is discharged into a receiving environment Volume = ~25Ml/d Salt content = ~4g/l Salt load = ~100 tons per day Dilution by around 5Ml/d from springs, much of it also contaminated, leading to little dilution This high salinity has had impacts on drinking water quality downstream and has been proposed as the cause of animal deaths and health effects in the Krugersdorp Game Reserve

17. Regional Closure Strategy Regional Closure Strategies have been developed by the DME in partnership with CGS, CSIR and Mintek. Acknowledge the underground interconnection of mines, leading to cumulative and integrated impacts on the environment and society, with multiple mines responsible for impacts within regions Key aspects Addresses water management, dust, radioactivity, ground instability, land sterilisation and socio-economic aspects Water management by integration within the mining industry and other liable parties Environmental protection can be ensured by the pumping of water to lower the mine void water level to the ECL and treating of water to a standard suitable for discharge (Stock Watering standard or better because of the proximity of the Krugersdorp Game Reserve) or sale to a third party Establishment of closure and monitoring committees to ensure meaningful stakeholder interactions and to maintain technical oversight of the process. This has already partially been achieved via the Technical Working Group and Monitoring Committee Apportionment studies found that ALL mines in the Western Basin who had or currently have rights to mine are jointly and severally liable (for example East Champ D�Or is listed as a asset on DRDGold shareholder publications).

18. Conclusions Pollution is as a result of current and historical mining activities which created and exposed contamination sources connected to an artificial aquifer within a natural groundwater system: Ingress of water into the mine void Flooding and decant of contaminated water is driven by natural processes �Shutting down the mine� won�t work! Enforce the �polluter-pays� principle Ensure that water volume, quality and pollution load issues are adequately captured in all EMPs and Water Use Licenses Enforce legislation to promote the development and implementation of short, medium and long-term solutions Ensure meaningful involvement of stakeholders