OPTIMISING WATER USAGE, LIMITING OUR IMPACTS

Significant amounts of water are used in the development and growth of our assets. Access to this resource is crucial and in South Africa water is becoming a scarce resource. The risks associated with the limited availability of water in the country are high and intermittent water supplies pose a significant threat to the operational continuity of our mines and the profitability of our business. In FY13, a strategy to reduce dependency on existing ground water infrastructure was implemented and a group-wide campaign to reuse processed water initiated.

The holding capacities of the water dams at Kusasalethu have been upgraded. This involved desilting of these dams and enhanced pumping capabilities, both on surface and underground, to enable them to cope with the greater volumes.

At Kalgold, a comprehensive geohydrological assessment informed a revision of the water balance. Technical changes were implemented at the plant and tailings storage facilities to ensure maximum recovery of water for re-use. Similar work regarding capacity management as well as water efficiency has been completed at Doornkop.

Our South African operations do not draw water directly from surface sources, except for Kalgold which draws water from an aquifer. Our other operations source water from bulk water service providers and municipalities; surface water run off; water that enters into underground mining operations and is pumped to the surface; recycled water and boreholes.

^* FY13 excludes Evander and therefore some reductions from the previous year occured.

Both our absolute water consumption and intensity usage declined in FY14. Over the past five years, absolute water consumption has declined by 45%, and water use intensity by 48%. The reasons include the closure consuption of operations, efficiency drivers and change in definition.

The following drought-risk mitigation initatives continued in FY14:

• Installation of additional boreholes to supplement the water supply and ensure no mine stands idle owing to lack of water
• Implementation of process changes to improve water efficiency
• Optimisation of water separation and recycling systems
• Construction of larger return-water dams and the installation of large covered tanks to reduce evaporation

The total amount of water used for primary activities in FY14 16 495 284m³ (2013: 18 556 000m³). Harmony has adopted a group-wide campaign to reuse processed water so as to reduce our dependency on existing ground water. In particular, our long-term targets are to reduce the amount of water used for primary activities by 4.5%, while increasing the amount of water recycled by 5% and improving our water use efficiency as measured by the volume of water used per tonne treated. These targets are set to be reached in 2018.

At Hidden Valley in Papua New Guinea, the topography together with the high levels of rainfall and low levels of evaporation pose significant water management challenges. Two water management techniques in use are:

• controlled run-off of rainfall to prevent erosion and sediment entering the river system
• conservation of site-water used to limit the volumes of contaminated waste water discharged into the river system

Water discharged at Hidden Valley is treated first to remove cyanide. Water is discharged to maintain a small ponded area on the tailings storage facility as is required to maintain the integrity of the dam. The raw water drawn from the Pihema Creek is used for key processes in the processing plant and related ore processing activities. When combined with high rainfall and low evaporation, this draw creates a high positive water balance, which requires a high rate of discharge from the tailings storage facility and limits opportunities to recycle process water. Minimising raw-water use is also essential to protect the mine during occasional droughts when the river water available is greatly reduced.

The Hidden Valley operation treats all water to prescribed standards before it is discharged into the environment and the joint venture partners continuously monitor and manage the environmental impact of the mine on the Watut River system. All river impact studies have been integrated into Hidden Valley’s overall environmental monitoring programme. The overall sampling regime was revised to reduce the numbers of both sites monitored and samples taken, especially where there was replication. This has led to good cost reductions which continue.

The environment and mine operational teams at Hidden Valley meet on a quarterly basis, together with relevant representatives from Harmony and Newcrest, to review efforts to improve waste dump design and the compliance status of the tailings storage facility. Quality assurance/quality control programmes have been implemented to monitor construction of the waste dump and tailings storage facility. This programme included an assessment of the adequacy of sediment and run-off control measures. A significant improvement in waste dump design/build and tailings management is being achieved.

Furthermore, progress was made in reducing the discharge of mine-related sediment into the Watut River. There is scheduled monitoring of water quality, water extraction and discharges to ensure compliance with permit parameters, particularly regarding cobalt and turbidity. Lime dosing has continued at the Watut River so as to control acidity and dissolved metal levels. At the sewage treatment plant, new blowers and more frequent operator training have contributed to improved compliance with permitted discharge criteria. The outcomes and recommendations of the various monitoring reports have been used to inform management’s environmental management plans.

ACID MINE DRAINAGE

Acid mine drainage is the occurrence of highly acidic water, usually containing high concentrations of metals, sulphides, and salts as a consequence of mining activity. Major sources of acid mine drainage are drainage from underground mine shafts, run-off and discharge from open pits and mine waste dumps, tailings and ore stockpiles. Tailings and ore stockpiles make up nearly 88% of all waste produced in South Africa.

We manage fissure water at all our operations. When there is a risk that rising water levels underground have the potential to hinder access to our own ore reserves or those of other operations or to harm the environment, water is pumped to surface. Our water management strategy includes intercepting this water before it is polluted underground. When brought to surface, it is consumed as plant intake. As the mines in the Witwatersrand Basin are so interconnected, any tactical response to acid mine drainage on mine closure must be considered from a regional perspective. Harmony continues to work closely with our regional partners to identify the long-term risks of acid mine drainage and to establish sustainable solutions (See KOSH below.)

In Papua New Guinea, the issue is with acid rock drainage (which is the same as acid mine drainage) as a result of waste rock dumps. Environmental impacts are mitigated by adding lime to the water to maintain natural levels of alkalinity at the compliance point. Water sampling and studies continue to improve our understanding of acid rock drainage impacts and enable us to formulate plans for longer-term reduction and mitigation.