Sustainability / Environment / Waste

Waste

All operations re-use, recycle or properly dispose of waste generated, minimising waste sent to landfill and maximising opportunities for recycling or reprocessing waste to reduce costs and generate additional revenues.

Approach

Mining and metallurgical operations produce considerable amounts of hazardous and non-hazardous wastes which, unless properly disposed of, can be a threat to the environment. The costs of disposal can be high. Xstrata is committed to reducing the quantity and toxicity of the waste we produce and we aim to progressively reduce the quantity of waste we send to landfill by recycling as much as possible. Xstrata also operates a recycling business in North America.

All Xstrata operations have a waste management plan to reduce, reuse, recycle or responsibly dispose of waste they generate. This minimises the amount of waste sent to landfill, cuts costs and maximises opportunities to generate additional revenue, for example, from recycled precious metals. Waste management plans are tailored according to sites’ specific needs, which vary according to the activities taking place. Coal mines, metallurgical mines and smelters produce distinct wastes that must be dealt with in specific ways.

The wastes we produce include:

Waste rock from the removal of strata to expose ores or coal. This can be placed in disused open cut or underground operations, reused during site rehabilitation, or stock piled;
Tailings and slag from processing ore and concentrates, as well as coal mine tailings (known as fines) suspended in water. Where possible we recycle or reuse these wastes but otherwise they are stored in tailings storage facilities and dams;
The generation of high iron content waste is a major waste management issue for the zinc industry. At Xstrata Zinc’s operations, iron is removed as iron sulphate, known as jarosite, which is classified as a hazardous waste. At the Canadian CEZ and Spanish San Juan de Nieva operations, jarosite is transformed into jarofix, a solidified, stabilised, inert material, which can be disposed of into landfill. At San Juan de Nieva, the jarofix it produces is being used to rehabilitate a local quarry; and
Hazardous wastes such as hydrocarbons, heavy metal contaminated sludge and vehicle batteries

Waste rock

We store waste rock in dumps, which we rehabilitate by shaping rock piles and revegetating them to mimic the natural environment. A major environmental risk associated with waste rock dumps is acid rock drainage, which can occur when certain types of rock is exposed to air and water and forms sulphuric acid. The acid leaches heavy metals (such as lead, zinc and cadmium) from the ore in the waste rock. Left unchecked, this can contaminate land and water sources. We reduce the risk of acid rock drainage by capping waste rock dumps to prevent contact with air or precipitation.

Tailings and slag

For the safety of our employees, local communities and the environment it is essential that tailings dam integrity is maintained. The failure of a tailings dam would be a catastrophic event. Also any leakage from a tailings dam can pose a threat to water quality. Hence they must be properly designed and managed.

Our tailings dam storage facilities are designed to international standards and are subject to regular external audits and risk assessments to maintain their integrity. No Xstrata operations dispose of tailings into rivers or seas. When we plan tailings facilities we take worst case scenario weather and geological conditions – including the potential for earthquakes, prolonged heavy rainfall or flooding, and landslides – into account. We conduct regular assessments of their physical stability and monitor groundwater to ensure leaching does not occur. Operations progressively rehabilitate tailings dams to prevent air and water pollution.

The traditional way to manage coal fines is to mix them with water to produce tailings. We are looking at innovative ways to reduce this waste.

We produce slag as a by-product of our smelting operations. In many regions, we use it or sell it commercially as a substrate for road construction, an aggregate for building, or to make bricks. In South Africa, slag from chrome mining is currently classified as a hazardous substance so its use is prohibited. Xstrata Alloys is working with the South African Department of Environmental Affairs and Tourism to determine the criteria for slag to be reclassified. We are conducting tests to show that acid is not created when rain comes in contact with the slag. The results of these tests will form part of the discussions with the South African government in 2009.

Hazardous waste

We take action to minimise the hazardous wastes we produce, most of which results from our smelting operations. Where generating hazardous waste is unavoidable, we recycle as much as possible and dispose of the remainder in approved landfill sites.

Recycling

We are among the world’s leading recyclers of materials that contain precious metals including gold, silver, platinum, palladium and copper. Recycling extends the life of metals and reduces waste sent to landfill.

Increasing global usage of electronic products, together with changes in the European Union’s Waste Electrical and Electronic Equipment Directive that require all electronic scrap to be recycled, mean that we receive a growing supply of electronic scrap for processing.

Managed by Xstrata Copper, Xstrata Recycling is one of the world’s largest recyclers of metallic copper and electronic scrap including printed circuit boards, integrated circuit and mobile phones. It samples materials at facilities in Rhode Island and California to analyse their content, then processes them at the Horne Smelter and CCR Refinery in Canada. We recycle over 125,000 tonnes of metal-bearing materials through these facilities each year.

Our smelter dust treatment plant at Altonorte in Chile, completed in January 2008, enables us to safely recycle stockpiled metallurgical dust generated during copper processing.

When Xstrata acquired Altonorte in 2006, 22,000 tonnes of smelter dust were stored on the site. We anticipate the new plant will recycle all the historical dust by the end of 2009. Approximately 90% of the copper contained in the dust is recuperated.

At Mount Isa we recycle tailings for use as a partial concrete substitute and filter engine and transmission oil to remove particulates and enable oil to be reused.

Last Modified on September 18 2009, 13:19:00 PST

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