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An evolution of the methods for and purposes of mine closure cost estimating

Jeff Parshley, W. Bauman, D. Blaxland
Wednesday, September 9, 2009
First presented: 
ACG Mine Closure Conference - 2009
Published paper
The last two decades have seen a significant evolution in both the methods for and purposes of closure cost estimating. As part of this evolution, changes in the uses of closure cost estimates have resulted in coincident changes in the scope, methods employed and level of detail required.
Prior to the development of regulatory requirements to prepare closure cost estimates, closure cost estimates were typically intended for planning, design and contracting of the actual closure, and were often developed late in the mine life cycle. The level of detail required was largely determined by the number of years remaining in the operational life of the mine at that time. The nearer to the time of closure, the more detailed the closure design and cost estimate became. These closure designs became the basis for construction contract bidding and tracking purposes.
As mining laws changed and the need to provide financial surety for closure activities became a priority, the focus of closure cost estimating in many countries was to reduce the liability of the government that would assume responsibility should the operator abandon the site prior to planned closure.
The latest evolution of closure cost estimating techniques has been focussed on improving closure cost estimating for the purpose of accurate reporting of financial liabilities to shareholders, lending institutions and governments. Requirements for reporting mine closure liabilities have added a new dimension to the scope and detail of closure cost estimating.
This paper documents the history of mine closure cost estimating since the 1970s and discusses the influence that different purposes for mine closure cost estimates have had on the evolution of methods used to develop those estimates. Several examples of successes and failures in closure cost estimates for actual mine sites and the regulatory programmes that oversee the closure of these mine sites are presented as illustrations of the progression of closure cost estimating and demonstrate the importance of this discipline in the mining life cycle process. Current trends in the current best practice and their probable impact on the future of closure cost estimating are also discussed.

Feature Author

Jeff Parshley

Jeff Parshley has more than 30 years of project experience throughout North America, Latin America, Australia, Asia, Europe and Africa, which includes mine permitting, environmental audits, feasibility and due diligence studies, mine closure design and permitting, liability assessments, reclamation and closure cost estimating, pit lake studies, mine waste studies and environmental geology. He has considerable experience in the permitting and closure of gold heap leach operations in the western U.S. and has lectured in the U.S., Latin America, Europe, Australia and Africa on mine closure planning and design. He regularly heads multi-disciplinary teams on projects ranging from environmental liability assessments to permitting to mine closure. He is currently carrying out a number of mine permitting, remediation and environmental geochemistry projects, a large underground mine expansion and several permanent mine closures.

Corporate Consultant, Mine Closure
SRK Reno
SRK Africa