Drilling considerationsI guess to many it may be quite obvious but I thought I would highlight why the large diameter drill is the tool of choice to determine grade. Looking at the sawn diamond core photo from the scout drilling update it looks as though the diameter of the core is only 95mm when going off the measuring tape above. That´s really quite small. The 17.5 inch (44.45cm) large diameter RC drill will take a sample over a much greater surface area - actually 22 times! The chance of hitting a nugget in this extremely nuggety conglomerate will essentially increase 22 fold.
A=π r 2 Diamond hole surface area = π times 4.75 squared
= 70.88 square cm
Large diameter RC surface area = π times 22.225 squared
= 1551.79 square cm
1551.79/70.88= 21.89 (22 times)
Considering that the sorted concentrate from the first bulk sample represents only 2% of the
overall sample weight and contained 82.6% of the gold, it is easy to see how important the large
diameter drilling will be in establishing a reliable picture of grade. Basically if you blindly put the
diamond drill on the same first bulk sample trench and drilled the chance of hitting some of the
good stuff ( weighted at 2% of whole sample) is very unlikely. I would expect the larger diameter
RC drill covering 22 times the surface area of the diamond drill will have a better chance to show
some gold and this is precisely the reason it is the tool of choice in determining grade. The
diamond drill is useful for other geological information but certainly has it´s limitations regarding
indications of gold in an extremely coarse gold conglomerate.