RE: last results producing costI'm surprised that the entire gang hasn't jumped on you with both boots. Are you a "basher" or just a "detractor"?
You are correct, the last batch of results wasn't that good. However, those drill holes were from the eastern edge of the IP anomaly. NC07-55 (prior batch of assays) was a much better hole, although it's only 25 meters from the rather mediocre NC07-47. Unfortunately, I can't look at the drill core photos on the web site and see/guess the grades. NC07-68 looks pretty good. Maybe the better grades are to the west. We'll have to wait and see.
I look at it this way--are the drill holes going to increase or decrease the resource grade when added? So far, they are going to decrease.
Acadian has a cost of $13.50 to mine a metric tonne (mt) of open pit ore. They anticipate a strip ratio of 10:1 from what I remember--I would assume that this cost includes the waste stripping and disposal. Their open pittable resources are about 3% zinc. I was going to wait for them to release their quarterly results before looking into this again (they just started up).
Not sure about the gravity concentrator. Yukon Zinc references a concentration process before their final milling process. I assumed that this was to reduce the amount of mill feed to save cost.
Also remember that most of these VMS deposits assume a certain amount of ore dilution--usually because they can't mine everything due to ground conditions. Then there's the amount of zinc payable--what the smelter actually pays. From what I've seen it could be between 80-85% depending on the level of imupurities in the concentrate. The lead will probably have the same issue.