Well, fool, that would be the tonnage factor. If I were only more glib of factotum sichlike, surely greater wealth and happiness would be mine forevermore.
(I only addressed him as fool, because, dear reader, that is a short, or affectionate moniker that betokens his "handle" or netname - "trading fool". I assure you that I hold the gentleman in high esteem.
It may shock the reader to the very core of his investing being that small details sich as these, figured wrongly, did almost? bring down, one mighty mining company, who mined one of nature's wonder metals, tungsten, in the far off forests of northern Canada. Yes, I believe it was Canada Tungsten who did not TEST their ore for number of tons in a volume, (it was less not more, due to oxidization) and thus figured the profits, as positive. But, lo, they were negative, due in part to the assay per ton, so accurately done in the lab, not equivalating dollar wise to the calculation of the metals % times tonnage of ore so contained within the mine.
What you do, if in doubt, and I say not too lightly that there is ample room in sulphide mines for doubt, is a crude but effective volume test. One takes a wooden box and fills it with ore, weighs it, then pours water in to the brim and weighs it again. Then you have the SG of the ore. True, not false or assumed.
At TG in the sixties they used to use a tonnage factor of ten cubic feet for a short ton (2000 lbs) of ore. This was considered conservative to err on the side of, for "massive to semi massive sulphides". The geology department during the exploration phase used this factor in calculating the tonnage of the first releases of ore information to hit the public. They were probably conservative by about 25%.
Pyrite is 5.5 SG. This means that an ore 100% pyrite is, per cubic foot, 5.5 X 62.4 pounds or 343.2 lbs!. Which is a miniscule 5.82 cu feet per ton!!! If a cubic metre were solid pyrite (it is 35.313 cubic feet,) it would weigh 12,119 pounds, or 6.059 tons.
Let me assure you that there are few ores in the world today, even in massive sulphide mines that use a tonnage factor of as little as 6. There is usually enough rock even in a massive sulphide ore that even to go as low as 8 cubic feet per ton is rare.
A silicate mine or gold mine is mostly quartz of an SG of 2.65 approx. The tonnage factor most often used in gold mines is 12 cubic feet per ton.
EC<:-}
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