Research is underway to develop a range of methods for assessing and managing exploration risk, progress, and value. As part of the research, a collaborative project was undertaken by SRK Consulting, working with Placer Granny Smith (the operating company of the Granny Smith Joint Venture owned by Placer Dome Asia Pacific, 60%, and Delta Gold, 40%) and Placer Dome Asia Pacific, to review and quantify exploration success in a mature program that has delivered several mines. In particular, an objective was to develop a measurement technique that is more commercially robust and informative than the traditional “cost per resource ounce discovered” method.

The project reviewed gold exploration over the past 13 years in the Laverton district of Western Australia. Placer Granny Smith has spent AUD$52 million (about US$30 million at recent exchange rates) defining 12 deposits with combined resources of more than 10 Moz (310 tonnes) of gold. Exploration centered on the Archean Granny Smith gold deposit, and was primarily targeted at outlining additional resources to feed through the Granny Smith mill. At an overall cost per resource ounce of less than US$3, this has clearly been a successful program. However, our analysis demonstrates that this figure fails to provide a complete value picture, and that the program could have delivered even greater value to the participating companies.

While the quantitative results of the review are specific to the Laverton district, the methodology can be applied to near-mine, advanced, and grassroots exploration programs for any deposit style in any geologic environment. Key outcomes of the review are as follows:

  • Measuring exploration success in terms of the net present value of the deposit outlined produces a markedly different and arguably more commercially realistic outcome than measuring it in relation to the average cost of resources defined.

  • Early recognition and prompt drill testing of key targets is critical in optimizing opportunities and realizing exploration value. Indeed, the principal destroyer of value in exploration is spending too much time and money prior to drill testing the best targets in any area.

  • Continual and robust ranking of exploration targets should be undertaken. Exploration should aim to rapidly identify and systematically test the best exploration targets, rather than systematically exploring the project areas.

Especially in the current climate of a depressed resources sector, the exploration industry needs to compete aggressively for the investor’s dollar. The industry needs more robust and quantitative methodologies for measuring exploration effectiveness, and for informing management, investors, and shareholders of exploration risk, reward, value, and progress to discovery. The probabilistic methods described below provide such a framework.

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