Case study

McArthur River Mine

ProjectMcArthur River Mine Surface Water Management
ClientGlencore Xstrata
Location40 km South-East of Darwin, Northern Territory, Australia
CompletionOngoing since 2011
Disciplines/ServiceFlood Impact Assessment
Surface Water Management
Mine Site Water Balance
Establishment of Water Monitoring Network
WRM ContactDr Sharmil Markar

The Challenge

MRM is one of the world’s largest providers of Zinc in bulk concentrate form. McArthur River Mine (MRM) proposed to expand its open pit zinc/lead/silver mining and bulk concentrate processing operation commencing in 2012.

Surface water management at the MRM site is quite complex. The site is affected by flooding from the McArthur River and several of its tributaries. Risk to mining and mining infrastructure from flooding has to be minimised.

The site generates significant volumes of contaminated water from overburden dumps, the open pit and underground mine voids and process areas. Runoff from these areas must be managed to avoid discharge of contaminated water into downstream watercourses. The excess water on site has to be managed within a strict regulatory environment.

The challenge for the surface water management strategy for the expanded mine site is to use as much as possible the existing surface water management measures, and implement the necessary changes to the existing mine site surface water management system to accommodate the proposed changes to the mine site layout, and to mitigate potential surface water and flooding impacts.

Approach and Key Activities

As part of the Environmental Impact Statement (EIS) for the proposed mine expansion, WRM was engaged to undertake a surface water assessment for the MRM site and propose the additional surface water management measures to be implemented during both construction and operational phases. The key tasks of the surface water management strategy at MRM included:

  • Identifying potential surface water impacts and mitigation measures;
  • Identifying potential flood impacts and mitigation measures;
  • Estimating the mine site annual water balance; and
  • Establishing a comprehensive surface water monitoring network to monitor the impacts of mining.

Outcomes

The surface water management strategy and plan prepared by WRM was approved by the regulating authorities in July 2012. The surface water management plan was also exposed to public scrutiny as part of the EIS public consultation process and scrutinised by an Independent Environmental Monitor appointed by the Northern Territory Government.

WRM has prepared annual water balance reports since 2011 as part of MRM’s annual Mine Management Plan reporting to the Northern Territory Government.

After the approval of the EIS, WRM has been retained to provide on-going operational surface water management advice for the MRM site including undertaking additional drainage and flood studies, designing new water management infrastructure, annual water balances and providing advice on regulatory matters.