Sculpin,

I have a question about your hypothesis here. Your drawing illustrates a side(longitudinal?) view of the intersection of a vein and a drill hole. What's not clear to me is what this looks like in a plan (overhead) view of the same situation. Are veins like planes that run in directions where a drill is sure to hit them (if drilled perpendicular to the plane, at an angle to intercept), or are they more like pipes that could be (partly) missed if the drill doesn't intersect them squarely? I'd try to illustrate this, but I don't have the tools at my disposal.

If veins are like planes, and homogeneous (more or less) along their long axis, then your geometry is correct. If the veins are more like pipes (leading more or less down) then the drill may have intersected only a portion of it (although the probability of hitting one pipe with another at depth is slim). If the veins are not homogeneous at different depths then the drill could have gone through a rich or poor representation of the total (no way to tell without digging it all up).

No matter how you look at it, the drill results are only showing a very small sample of what's down there. We're talking about drilling 50 cm holes (2 inches for those of us who were raised before the metric system) in hectares (square miles, for the elderly amongst us) of ground, and at angles no less. Kind of like looking for a needle in a haystack. I realize it's the best exploration technology available, but should we read too much into the results, or should we be comforted or dispirited by the indications alone?

I'm not trying to discredit your work. On the contrary - I have learned so much from your technical interpretations in the past. This is just one area that I've yet to understand.

NoWorries