Environmental-best-practice mining research well received internationally

17 February 2010

		Mining has been part of New Zealand’s history since the 1800s, producing gold, coal, aggregates, industrial minerals, limestone, and iron sands. It is an important part of the economy valued at approximately $1.5B/year (Crown Minerals 2007 – excludes petroleum). However, mining can have significant impacts on the environment, and so must be managed in a way to minimise those impacts and ensure environmental sustainability. CRL Energy’s Christchurch team spearheads a Foundation for Research, Science, and Technology-funded, multidisciplinary research programme on the application of environmentally acceptable practices to mining activities – particularly to address the problem of acid rock drainage and its impact on waterways.
The consequences of poor management of acid mine discharge. Left, upstream of acid mine discharge. Right, iron oxide coating present on rocks downstream of acid mine discharge.

The research team, which includes sub-contractors from Landcare Research, the University of Canterbury, and the University of Otago, has developed a framework which draws together research on rock geochemistry, aquatic chemistry, freshwater ecology, aquatic toxicity, and management and remediation techniques for mining. In the framework, water quality is the key parameter enabling prediction of the likely ecological impact and selection of management or remediation options.

While the focus of the framework is to assist with planning of future mining operations on the West Coast and in Southland, the information provided is also relevant to existing mining operations, or for the selection of remediation options for historic mining operations.

CRL Energy’s Geology Group Manager, Dr James Pope, says the framework will provide useful information for consent processes, access negotiation, and assessment of environmental effects. “The intended audience for the framework includes regulators, mining companies, land holders, consultants, and the community, and the objective is to prevent, minimise, or mitigate mining impacts on water quality and aquatic ecosystems downstream of mines. Specifically the framework provides information on collection of water, rock, and biological information used to predict water quality prior to mining, monitor discharges from mines, and identify mining impacts. The framework also provides information on methods and pitfalls in the interpretation of this information. In addition, the framework includes information on state-of-the-art techniques for prevention of poor water quality in mine drainages, optimal strategies for management of mine waste or overburden, and remediation of mine drainages if necessary.”

As this major research programme draws to a close (officially finishes September 2010), communication requirements of the research are increasing. CRL Energy’s Environmental Hydrogeologist Dave Trumm, and Dr Pope presented four peer-reviewed papers at the International Conference on Acid Rock Drainage (ICARD) in Sweden in June 2009. ICARD is the premier international event for mine drainage research.

“The material we presented was very well received, especially a paper on remediation of arsenic-contaminated water using waste products from mine drainage treatment by CRL Energy’s Environmental Geochemist Dr Rachel Rait. In general the research generated considerable interest and opened options for international collaboration,” says Dr Pope.

CRL Energy and subcontractors hosted a workshop at Environment Southland. The workshop was well patronised by attendees from the Department of Conservation, Regional Councils, District Councils, FRST, Solid Energy, and private companies. The workshop was split into two parts, a multidisciplinary presentation from the researchers and an exercise where the framework document was trialled on a hypothetical mine development for lignite and alluvial gold in Southland. At the end of the workshop an open forum panel discussion provided a free exchange of thoughts and ideas. Feedback from the attendees including FRST was very positive.

Chief Executive Dr Rob Whitney says the programme continues to overachieve on outputs and has been a catalyst in developing a special edition of the New Zealand Journal of Geology and Geophysics devoted to mine drainage issues.

“The research team were also invited by FRST to submit a proposal into a new research portfolio where the skills developed here might be put to use on different research problems.”

Dr Trevor Matheson
Manager: Operations