William E. Roscoe and John T. Postle have collectively dedicated over eight decades to shaping and revolutionizing the world of mining consulting and standards development. With their exceptional expertise, pragmatic approaches, and relentless commitment, they have left a permanent mark on the industry.

Their dedication to establishing trustworthy regulatory frameworks has created international standards, enhanced investor confidence and facilitated financing efforts for numerous mining companies.

Roscoe, born in Hancock, Mich. and raised in Ontario, began his journey in the mining industry with a B.Sc. (Eng.) in geological sciences from Queen’s University in 1966. He went on to earn a master’s and Ph.D. in geological sciences from McGill University in 1969 and 1973, respectively. His extensive educational background laid the foundation for a remarkable career.

Roscoe started as an exploration geologist at Cominco in 1966 and later served as a senior geologist at St. Joseph Explorations from 1976 to 1981.

Postle, a professional mining engineer, born in Kirkland Lake, Ont., started his career with a B.Sc. in mining engineering from the University of British Columbia (1965) and a master’s degree in earth sciences from Stanford University (1968).

Postle worked for major mining companies Cominco and Falconbridge, gaining invaluable experience in open-pit and underground operations.

Roscoe and Postle met when they worked together at Cominco’s Wedge Mine in New Brunswick in 1967. Both spent time in senior positions at the mining consulting firm of David S. Robertson and Associates before venturing into consulting on their own.

In 1985, they co-founded Roscoe Postle Associates Inc. (RPA), a consultancy that would become a titan in the mining industry. Under their leadership, RPA flourished, growing into a nationally and internationally recognized geological and mining consulting firm with offices in Toronto, Vancouver, Rouyn-Noranda, Quebec City, Denver and London, U.K. Their commitment to professional and ethical standards made them the go-to firm for resource/reserve estimates and audits, technical due diligence, and mining valuations.

Throughout his career, Roscoe’s influence extended far beyond RPA. His contributions to the industry include co-leading the development of the CIM Valuation Standards and Guidelines for Mineral Properties (CIMVAL), and publishing papers on valuation methodology. Bill’s involvement with the International Minerals Valuation Committee (IMVAL) and the International Valuation Standards Council further solidified his global impact.

One of Postle’s remarkable contributions was his role in developing the CIM Mineral Reserve/Resources definition standards, which became part of the globally recognized Canadian National Instrument 43-101. His involvement extended to the international stage through CRIRSCO, where he helped define international reserve/resource standards.

Throughout their careers, Roscoe and Postle have been recognized for their outstanding contributions. Both were awarded fellowships, named distinguished lecturers and received the Robert Elver Mineral Economics Award, all from CIM. In 2022, Roscoe received the Vale Medal for his meritorious contribution to mining. Postle was awarded the Queen Elizabeth II Diamond Jubilee Medal for his service to the mining industry, and they jointly received a PDAC Special Achievement award for their contributions.

Their work at RPA, now part of SLR Consulting Ltd., has set the gold standard in geological and mining engineering consulting, mineral valuations, and resource/reserve work.

Roscoe and Postle are not just pioneers; they are pillars of the mining community. Their profound impact on consulting, standards development, and the broader mining industry will continue to shape its future for years to come.


Paul Penna was a successful mine maker and the builder of a substantial corporation destined to thrive long into the future. As chairman and president of Agnico Eagle Mines, he brought his company from small beginnings to senior status.

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