Client name: BHP Billiton-GEMCO 

Duration: 2010 - 2012

Location: Groote Eylandt, Northern Territory, Australia 

By handling all aspects of a detailed groundwater investigation and water management study in a remote tropical location, we modelled and delivered water management technical solutions for BHP-Billiton-GEMCO in a timely and cost-effective manner.   

Groundwater investigation for dewatering of potential manganese ore mine

GEMCO were investigating the potential to mine manganese ore from leases located within strategic quarry areas on remote Groote Eylandt, located in the Gulf of Carpentaria. As part of the mining process the quarries would require dewatering to specified dry levels. An extensive investigation would be required to underpin water management and drive the necessary environmental approvals process. 

Aquifer pumping tests and numerical groundwater modelling

Coffey addressed the challenge by undertaking a staged water management investigation that included targeted field investigations including aquifer pumping tests and numerical groundwater modelling.

Our work program addressed the key objectives of the study. These were to investigate the hydrogeology of the mine region, to assess the impacts of mining activities on the groundwater and surface water systems, and to provide estimates of quarry dewatering rates.

Our field program required installation of 32 groundwater investigation and monitoring wells, and conducting two 48-hour constant rate pumping tests to determine aquifer characteristics. In addition, we mobilised for two groundwater sampling events to establish the dry and wet season baseline conditions.

Based on the outcomes of the field assessments, we were able to develop a detailed site conceptual model and numerical model to predict the potential impacts on the environment due to dewatering.

The completed numerical modelling and water management study has supported subsequent management and impact assessment studies completed across the site that are required to expand operations and achieve project approvals.

Cost-effective and on-time hydrogeology, environmental impacts and quarry dewatering rates investigation

By handling all aspects of this broad based investigation, including the logistics of establishing a drilling contingent and considerable supplies and equipment on this remote island, we delivered modelling and water-management technical solutions for BHP-Billiton-GEMCO in a timely and cost effective manner.