Sustainability website / Case Studies 2003 / Xstrata copper / Hummingbird Electromagnetic (HEM) Survey

Hummingbird Electromagnetic (HEM) Survey

Several Xstrata Copper sites in Australia have adopted the use of conventional, exploration electromagnetic surveys to improve environmental management through improving management of seepage control.

An electromagnetic survey was completed over the tailings dams at Mount Isa in 2003 and following 1,547 line-kilometres of data acquisition, was successful in delineating a number of high conductivity areas directly associated with tailings dam seepage and mining activities. Conductive regions, not associated with natural mineralisation, were defined in several areas around the operation and ground validation is planned. At each of the tailings storage facilities, conductive trends have also been defined. The majority of these conductors are associated with minor creeks and faults at the margins of the dams. The integration of the results from the survey with regular borehole monitoring will provide a better understanding of the hydrology on the Mount Isa Mines lease and enable the development of strategies to improve management of tailings seepage where necessary. Overall, the technique has proven to be an invaluable and cost-effective means of acquiring an accurate and comprehensive overview of potential seepage and contamination issues associated with mining activities. Using these techniques, zones most affected by the impacts of mining related activities can be readily delineated for subsequent detailed field-based investigations. The work completed at Xstrata Copper's sites in Australia over the past few years has demonstrated that the technique has application in all aspects of a mining project lifecycle from feasibility, to operation, and into decommissioning.