Unrelated to your post, I thought some would find this commentary of value:
The Northern Miner Volume 85 Number 19 July 5-11, 1999
LETTERS TO THE EDITOR -- PGE-related reports need guidelines
The Northern Miner deserves applause for its recent editorials on salting scams, "boutique" assay labs, and associated frauds -- not least of which are the "black sand," or "desert dirt," boondoggles of the western U.S. Fraudulent "mirage deposits" will not go away any time soon, but clarity of language can cast some light on many bogus schemes, and should be de rigueur for serious and well-managed projects.
Experience indicates that of all metal-related exploration projects, the ones most likely to be misinterpreted by investors are those that contain platinum group elements (PGE). Exploration companies and the mining press alike, both here and abroad, bear some responsibility for the shaky terminology employed in news releases and articles. The resulting confusion could be minimized by some basic guidelines. The following suggestions are offered:
The metals in question are platinum, palladium and rhodium, plus the more refractory and generally lesser-known ruthenium, iridium and osmium (in chemical-speak, Pd, Pt, Rh, Ru, Ir and Os). Gold (Au), silver (Ag) and rhenium (Re), also heavy precious metals, are not PGE.
The six PGE are distinct commodities with widely (sometimes wildly) disparate prices. In general, early-stage PGE exploration projects are concerned mostly with platinum, palladium and gold plus associated base metals, such as nickel, copper, cobalt and chromium. Different proportions of PGE and gold have profound implications, both economic and geological. Thus, summary data should quote Pt, Pd and Au values separately, and any "lumped" data (Pt plus Pd plus Au, or all six PGE plus Au) should be used only in conjunction with some meaty, element-specific data.
While imperial units can, in principle, be used, the case for metric or S.I. units is much stronger for PGE than for silver or even gold. Parts per million (ppm) and parts per billion (ppb) are by far the most-elegant, least-ambiguous choice. Let's not forget the point of all this, which is to advance the state of reporting with exactitude and clarity (and at least force the scam artists to lie more precisely). Bear in mind that a set of minimum detection limits for routine exploration may be something like 5 ppb Pt, 2 ppb Pd and 2 ppb Au.
The PGE usually occur together in variable but often characteristic proportions, commonly invisible within host phases such as base metal sulphides. In high-grade ore, they may also reside in a bewildering range of discrete platinum group minerals(PGM).
Critical reporting must verify assay units. A recent article (T.N.M., May 31/99, page B15) provides both an example and a self-consistent explanation. The article quotes an intersection of 69.34 metres grading an average of "0.0074 gram" combined platinum-palladium-gold plus elevated nickel and copper values. 0.0074 gram per tonne is the same as 7.4 ppb, similar to those typical detection limits. Also, 3.24 metres of this core assayed 1.6 ppm platinum-palladium-gold.
Recalculating this to the full length yields a mean of 74.8 ppb. The printed value was a factor of 10 too low. (A Pt:Pd:Au breakdown of the rich intercept would, in any case, be more informative.) The key point is the presence of 3 metres of potentially ore-grade PGE- and gold-bearing rock in a much wider, essentially PGE-void unit containing base metal sulphides.
It's a given that geology, the ideal preface to assay data, provide diagnostic insight into genuine projects and forensic clues to frauds. Remember how little we heard of Busang geology (the magic was all in the "ounces"). But that's another story!
All this may seem esoteric, especially when more mundane problems, such as visual misidentification of common ore minerals. But the current situation is agreeable only to those who benefit from confusion. The solution is simple enough, and with the platinum family scoring new headlines, it is time to put the house in order.
Graham Wilson
Campbellford, Ont. |
