Actually Don, it doesn,t matter much about the width of the veins, its more to do with the grams per ton grade of the veins. For example, you could be getting 7 g/t out of a 3m wide vein and 2.5 ozs per ton out of a 1m wide vein. See the difference when you take the 1m vein and put it to a reasonable mining width of 1.8m, you are still above the grade of the 3m vein, plus you lose off the width of the wide vein, making the grade less. Now you can stope these areas of wider vein to get the gold out, but the narrower high enough grade vein, will be more economical in shaft mining. Wider veins do give you more space to have gold in, but narrow veins tend to be mostly higher grade as a rule in most vein deposits. So really, the idea width for single vein mining could be around 1.8 m wide or a little less as long as the grade kept shooting up the narrower the vein got. Efficiency would be looked at from various angles, depending on the grade.

But when you talk of stock works and host rock mineralization, the idea changes where you will want to see volume that could warrant an open pit. Although the grade can be lower with an open pit, the ability to move dirt quicker results in more ounces being mined quicker. You could have numerous centemeter micro veinlets across an alteration with a low gold grade of a few grams today and be economical as an open pit. With the POG today, you don,t need very high grades to be economical, you just need enough in the right places. Many of these veinlets show up in historic data of the Tesoro, but it is unclear if those portions that the drills intercepted have been assayed for gold content. These veinlets sometimes can be mostly gold if the source is rich enough, and with the high grade pure gold globs from the A-4 vein, I say the source is very rich.

IMO