Ore Reserve Standards

With the purpose of furthering helpful discussion on the topic of ore reserves appearing in your last several issues, I wish to add the following fuel to keep the pot boiling.

The article “Computer Bugs” in the December, 1989, issue refers to three important principles, the second of which is the necessity for standards in determining ore reserves. This idea, however, that the same result must be obtained from identical data is, in my opinion, a direct contradiction of the principle that “professional judgment should always prevail over computer output,” which is the principle we agree should be overriding.

The standards we should be looking at are rather more broadly based, such as those set down recently in the February, 1989, publication of the Australian Institute of Mining and Metallurgy, detailing their code for reporting of identified mineral resources and ore reserves. (Here, the Aussies are way ahead of us.)

This standard puts the whole question of ore reserve determination into its proper perspective with its clear distinction between “geological or in situ” resource and “mineable or delivered-to-mill-with-economics-applied” ore reserve. One of its principal tenets, also, is the requirement of responsibility and competence in terms of a properly qualified person, with his implied judgment, as a signer of any resource or ore reserve report, and not by a first timer, as implied by the third principle in your article.

Whether a computer is used or not, is not nearly so important as the requirement of competence based on experience of reserves and its implied professional judgment, as noted in the first principle.

Computers will not and cannot do what you cannot do manually. The cad (computer-automated design) versions with their integrated capacity for plotting sections, plans and 3-dimensional models for geostatistical analysis and for mine-planning, will do the work much faster, more accurately and hence much more efficiently, subject always to proper use and judgment input at critical stages in the reserve determination procedure.

D. Wortman, P.Eng.

Vancouver, B.C.