whats narrow veins got to do with it?
posted on
Feb 18, 2012 08:11PM
Keep in mind, the opinions on this site are for the most part speculation and are not necessarily the opinions of the company WITHOUT PREJUDICE
Its a common thing to find the higher grades of gold found in the narrowest veins. Most of the richest vein miners in the world have an average vein width of ~2 meters. BUT, be careful when you think that I am just talking about the width of the quartz making up this vein, there are the attachements on either side that adds to the width of the quartz and makes up the width of the vein. See, a vein doesnt always consist of just pure quartz that carries gold, the host rock and structure that contain the quartz may also carry gold (as in our case) and have to be added into the mineable width of a vein structure.
So, for instance, there may be mention of a high grade narrow 10 cm vein at surface on the Tesoro. But the misconception begins with the width of the vein when someone assumes that is the true width of mineralization, and fails to understand that 10 cm could very quickly turn into a wider mineralized structure once you add in the rest of the alteration on both sides. So stop the oohs and arghs about narrow veins, and understand that some of these so called narrow veins are merely just constituents of a network that could measure 10,s of meters wide. For instance, think of why Lori says the mineralized main corridor was around 500m wide or better.
Our high grade veins are very economical to shaft mine right now and would no doubt compare to some of the richest vein miners in the world. You should have around 6-7 g/t for an underground mine, our averages from 2 of our small mines, (the C-1 and A-4) are coming in at around a combined average of ~ 24 g/t. (that average should be recalculated, because it seems to me that higher grade stuff from the C-3,4, may bias that grade further to the upside?) To do some simple math on this, a tonne of rock roughly measures 1m x 1m x .66m (i believe this is a correct measurement). A mininum width needed to mine a structure is around 1.5-1.8 m. So, if we have 24 g/t across 1 m, and we say what the hell to be consevative, and stretch it out over a width of 2m. That would give us 12 g/t average gold and is way above the mininum of 6-7 g/t to be economical in a shaft mine. If I were to use the calc,s from the 11 oz/t picture, well you get the picture why I won,t. Anyhow, nuff said on that subject, and you now know why the vein widths are not important as long as they have a high enough grade.
So, IMO, Lori knows we have profittable shaft mines on the Tesoro, but she wants more, like she said in her last interview we watched. She wants to prove up a bulk tonnage deposit. This would be lower grade, but, if successful, would prove up the most amount of ounces and enable us to get the best price in the event of an offer. So, we really don,t care too much about the narrow high grade intercepts in the NR, we want to see the long lower grade intercepts that are economical grades to justify an open pit. And to have this, we need the trenching results and what is between the intercepts reported to date on our drill cores. Don,t get me wrong, we still want ands need the high grade intercepts, but at this point, we need the other intercepts to see if its worth while trying to prove up enough tonnage for an open pit mine.
IMO,and as usual, I may be 100% wrong.