Rehabilitation, Remediation and Closure

We clear land to access mineral deposits and to enable construction of our operations and support activities.

Our operations create new landforms through the construction of waste rock or overburden stockpiles and tailings storage facilities. We also create large open voids as a result of our open-pit mining. We occasionally need to re-contour land to divert creeks and stormwater flows around our operations. All activities associated with creating or modifying landforms are strictly regulated and are undertaken only after appropriate studies are completed and approvals and licences have been received.

Where feasible, we rehabilitate cleared land as soon as we have no further need for access. We stockpile topsoil for future use and salvage vegetation from any land we clear. The first step in rehabilitation is to undertake earthmoving to return the land to an appropriate profile and revegetate with native species. The final step is monitoring the growth, development and spread of the vegetation and the return of fauna, until we are confident the rehabilitation is self-sustaining.

We maintain records of the land we have cleared and set annual targets for rehabilitation at each of our operating sites. Land disturbance, rehabilitation activities and targets are reported for each site.

Our operations also have the potential to impact on ground water through spills, leaks from pipes and storage tanks and seepage from tailings storage facilities. Where we have identified potential for groundwater to become contaminated, we install monitoring bores to monitor ground water quality.

As a temporary user of land, WMC is responsible for leaving a site in a condition that maintains the available options for the future use of the land. Sites that have not been properly closed may become a long-term financial liability.

WMC has developed closure plans for all of its current operations and also for some legacy sites. Site closure plans are reviewed and updated every three years to reflect changing legal requirements and expectations, and the estimated costs of achieving agreed closure criteria are reassessed. These closure plans are used to progressively allocate financial provisions to achieve closure at the end of the mine life.

• Read about our 2004 performance for Biodiversity and Land management.