Waste
We generate both mineral and non mineral waste during our mining and processing operations. Through effective management, we limit the negative environmental impact of our activities and reduce our operating costs and risks.
Our waste strategy allows us to improve our understanding of the true cost of dealing with waste. This in turn helps when planning for new projects and for closure, as these costs are often underestimated.
Our main focus is on the highest risk area: chemically reactive waste. This is a small percentage of our total mineral waste but potentially the most harmful.
By effectively managing our waste, we support improved environmental performance as well as our biodiversity and water programmes.
Our engagement around waste happens internally and externally.
Externally, we are active members of the International Network for Acid Prevention (INAP). Acid rock drainage (ARD) from mineral waste is one of the most serious environmental risks for the mining industry. ARD can be created when rocks that contain naturally occurring sulphide minerals are disturbed and exposed to air and water. This accelerates the natural weathering process and may lead to the release of low pH (acidic) contact water with elevated salinity and metals concentrations. If managed improperly, ARD can prevent revegetation of mining wastes, and degrade surface and groundwater quality.
Through INAP, we promote important research on acid rock drainage (ARD) prediction and control; promote knowledge sharing within the mining industry on new ARD management strategies; and support our commitment to responsible mineral waste management.
We regularly present at conferences such as the International Conference on Acid Rock Drainage (ICARD). We also actively participate in a number of scientific and regulatory communities through other conferences and workshops.
One of our current external programmes is supporting external research on vegetated store and release covers for chemically reactive mineral waste and on ARD mitigation strategies.
Internally, we have developed a number of programmes to improve mineral waste management and limit potential environmental impacts. Through these programmes, outlined below, we build awareness across the Group of the importance and value of strategic waste management.
Mineral waste management plans
All operations that generate mineral waste are required to develop a mineral waste management plan. These are designed to ensure appropriate management that minimises environmental impacts and controls all chemical and physical hazards posed by the waste.
Acid rock drainage management
To prevent or minimise potential environmental impacts of ARD, we have adopted leading practice in mine planning, operation and waste management. New projects are designed to ensure that the risk is minimised and that any ARD generated will be captured and treated.
Our strategies are also being refined to improve characterisation of acid generating materials; improve mineral waste handling procedures; develop effective closure strategies; and improve collection and treatment of ARD.
We use a number of techniques to prevent or control ARD. These include selective handling and encapsulation, disposal under water, blending waste materials, and using either synthetic or engineered earth covers.
We have developed an ARD Hazard Screening Tool to identify new high risk projects, mine expansions and acquisitions. All operations where ARD could occur must maintain a management plan that must be reviewed every four years by an external expert. Our internal ARD risk reviews are now regarded as the industry benchmark in this key risk area.
Mineral waste management optimisation programme
This programme offers direct technical support to those businesses that must manage significant chemically reactive mineral waste issues. The programme brings technical experts to the businesses to help them identify waste related risks, and to develop mitigation and control strategies to minimise potential environmental impacts.
