Bill, there must be something else, that will be the first time gold and platinum are disolved directly in pure HCl. Of course, if the gold particles themselves are extremely small (clusters of 100 to 1000 angstroms), then they will react with Hcl. But if that is the case, there will still be a bunch left in the roughly 25 to 50 micron size particles left behind. You do not expect HCl to diffuse into the quartz matrix and extract the gold there, do you?
By the way, are you talking about steam injections into the vats? That would require closed systems, otherwise you'll have a circa WW I chemical weapon all over the plant. You will need at least a 2 tons of water for each ton of dirt (probably much more because this is only about a 4 to 1 volume ratio, the cost of heating this to 90 C would be about $10 (take about $2 to heat a ton of water from 20 to 90 C just in electrical costs of 10 cents per KWH, I am taking five times that because I think you may need 4 tons of water for each ton of ore, plus the ore, and you will have a lot of evaporation and conduction losses). So with your $3 in chemical costs (what are you taking for hycrochloric acid anyhow, $20/ton, that is assuming a 2.5% concentration of HCl, which will not do much for Au, furthermore, I have seen any bulk concentrated HCl at $20/ton, barely pays to transport the stuff at this selling price) and dirt hauling costs (much lower than thall has on his charts from the bureau of mine, but his could be high, but a buck/ton?) we are already at $13/ton, that just gets the stuff into solution, to precipitate it and collect it what kind of costs do you have and what do you have for operating personel, you think that $17/ton will be sufficient? You also need to take into account amortization of these tanks, no lining really likes hot HCl for a long period.
That is a good exercise, we might still get to a realistic value somehow. I still have too many unanswered question, and one thing is clear, you cannot get these costs creep to the range of $70/ton, since the margins will no longer be there.
Bill, you may also find out what the expected through put is, somewhere they said the leaching takes an hour (seems short, but they must know), this way you can size the the vats required, taking about twice this interval to allow for filling and emptying.
Zeev |
