rehabilitation

Lorena Chirivella, Environmental Officer Minera Alumbrera, Argentina

Xstrata's Biodiversity and Land Management Standard requires all operations to progressively rehabilitate disturbed and contaminated land. With the exception of sealed sites, such as refineries, all our operations have procedures in place to ensure that disturbance is minimised and that, once land is disturbed, it is rehabilitated to an agreed land use.

During 2004, 659 hectares of disturbed land were rehabilitated while 2,362 hectares were disturbed throughout the Group. The mining of large open-cuts has resulted in 71% of the disturbance and 88% of the rehabilitation occurring in Xstrata Coal by the end of 2004.

In 2004, a number of operations continued to rehabilitate or decommission available areas:

• Rustenburg smelter closed its phase two slimes dam and rehabilitated an old return water dam;
• With the closure of its operation, Vantech began to rehabilitate unused mining areas and the tailings dump, and decommission infrastructure;
• In Queensland, Xstrata Coal continued progressive rehabilitation at Oaky Creek, Newlands and Collinsville mines. Work also started on the final rehabilitation of the Belmore Pipeline Pit at Collinsville;
• In New South Wales, all operations completed rehabilitation liability reviews and a standard for mine closure was introduced which outlines the requirements for developing, reviewing and carrying out mine closure plans and guidelines for the planning process so that all operations will meet statutory requirements and ultimately obtain release from security bonds; and
• Rehabilitation works undertaken within Xstrata Copper's operations included:
  • a large-scale field trial of rehabilitation techniques was established at Ernest Henry Mine, resulting in successful revegetation;
  • with the acquisition, demolition and revegetation of several properties, the Mount Isa copper and zinc-lead operations continued the development of a green belt separating the operation from the adjacent city of Mount Isa;
  • the Mount Isa copper and zinc-lead operations have developed a strategy to use waste rock from the Black Star open-cut mine to cap redundant tailings storage facilities and other redundant infrastructure to enhance progressive decommissioning and rehabilitation, and reduce liabilities associated with future mine closure and rehabilitation obligations; and
  • Alumbrera also completed a geophysical survey in the north of the tailings storage facility in the Tampa Tampa plain to quantify the alluvial material available for capping of the tailings dam at mine closure. The survey found that the alluvial materials covering this area were just sufficient, considering an area of 930 hectares needs to be capped with 1.5 metres of material. A drilling programme will assess the geology of the area which will provide additional data on the alluvial material. The mine also implemented a quality assurance programme, including a geologist's 'sign-off' for the construction and selective handling of materials to be stored in waste rock dumps;
• Following the closure of the battery recycling plant at Xstrata Zinc's Northfleet operation in December 2003, a period of initial plant cleaning took place early in 2004, surface water ponds were emptied, cleaned and jet washed, and materials storage bays are presently being emptied; and
• The surface of jarosite pond number one at San Juan de Nieva was rehabilitated.