I caught part of an interview today on BNN. I,m not sure of the guy,s line of work that was being interviewed. I didn,t catch it but suspect he was an analyst, geo or both. Anyway, what he said was;

1) when investors are doing there DD on gold mining stocks, rule of thumb for today is; you should have at least an average grade of 1 g/t gold for an open pit mine. Open pit mines usually go down to 300-400 m. He stated one exception; Detour Gold, which currently has an open pit gold mine of around 700m. (there are much bigger/deeper ones in the world, but I suspect he was just using an average depending on the size of the deposit and property.)

2) After the usual 400m open pit, you would probably shaft mine, if the resource continued at depth. He said in this case, then you would probably need around 4 g/t to make it economical.

It was good to hear this come from a professional and is right in line with the conservative numbers we have been using for showing that the Tesoro has a high probability of being economical . It makes me think of one of the bulk samples that came out of the A-4 vein;

2007-07-02 39 A4 4.100 244.210 11.224 46.018 41.417

I copied it from an older technical report, but it didn,t come out right on this post. I will explain the numbers;

A 4.1 ton bulk sample graded 11.224 OZS per ton or approx 348 G/T for 46.018 OZS mill grade with 41.417 OZS recovered after processing.(The gold recovery rate for this sample was 90%, hence the lower ounce number than the mill grade)

I am using one ton of rock being equivalent to 1 m cubed for this example. If any one has the right size of one ton of rock, please post!

How many meters sideways could you streatch this sample at 1 g/t?

Answer: Approx 1392 grams total/ 1 g/t = 1392 m

So, if we stretched this bulk sample out to average the 1 g/t required for economical open pit mining, it would reach 1.3 km in a straight line of 1 meter cubed.