Post-Closure Groundwater Impact Assessment for the Underground Mining Operation at Olympic Dam

Author(s): 
C.M. Linklater, S. Ogier-Halim, J Chapman, M. Tyler and G. Hill
Date: 
Monday, August 17, 2015
First presented: 
Australasian Mine Rehabilitation (AMR) Conference
Type: 
Published paper
Category: 
Water Management

The current BHP Billiton Olympic Dam (OD) operation comprises underground workings (tunnels, stopes) and a number of surface facilities including the TSF and processing plant.  Mined out stopes in the underground workings are backfilled using cement aggregate fill which includes a portion of process tailings. Current life-of-mine plans indicate that the underground operation will continue for at least another 45 years.  At the end of mine life, dewatering will cease, and the underground workings will re-flood.  An assessment of the potential impacts that the Olympic Dam underground operation could have on the regional hydrogeology and groundwater quality in the intermediate and long term is required to support development of closure plans for the mine site.

During the period 2007 to 2011, OD considered the option of developing a large-scale open pit mine operation.  Groundwater modelling and TSF source term assessments were conducted (SWS, 2010; SRK 2010) to support the environmental impact assessment of that proposed development (BHP Billiton 2009; 2011). The current assessment utilised material from these previous assessments where possible; however, modifications were necessary, in particular to the groundwater model, to reflect the change from an open pit to an underground operation

Feature Author

Claire Linklater

Claire Linklater has 22 years’ experience in interpretation of geochemical data, building conceptual models of processes which control in situ geochemical behaviour and the application of geochemical modelling codes.  Her early career was focused on management of radioactive wastes; understanding and quantifying the geochemical behaviour and mobility of radionuclides in the ‘geosphere’ surrounding a proposed underground repository and assessing the long-term stability of engineered and natural barriers.  More recently, she has focused on sulfidic materials management: acid/alkaline rock drainage (ARD) assessment and prediction; water quality and pollutant mobility from waste rock dumps, tailings storage facilities, underground workings and pit walls; assessing the effectiveness of potential mine closure strategies.

Principal Consultant (Geochemistry)
PhD (Geology), FGS, FAusIMM
SRK Sydney
John Chapman

John Chapman has more than 26 years of relevant experience and has developed multi-disciplinary skills relating to mining environmental impacts assessment and environmental controls.  He is a recognised expert in ARD assessment and prediction, mine waste characterisation and management, and mine closure with recent project experience in Australia, South East Asia, Canada, USA and Europe.  John has facilitated enterprise-wide risk assessment workshops, undertaken due diligence and environmental risk assessments for a wide range of mining projects.  Recent projects include detailed geochemical assessment of the tailings properties for the Olympic Dam Project in SA, design and development of the geochemical characterisation program for the Cannington Life Extension project in QLD as well as for the Yeelirrie Project in WA.

Principal Consultant (Geochemistry and Environment)
MSc (Chemical Engineering), P Eng (British Columbia), P.Eng (Yukon Territory)
SRK Brisbane
SRK Latin America