RE: Top up8 Sep 2018 19:36
You're welcome builder. Well done for doing so. I can't recommend enough the importance of having some knowledge on this matter - if not, I would say stay the hell away from investing in junior exploration stocks. You will lose your money eventually. If you look at the end of asx drilling or resource announcements, they give a table of methods used etc. That's a good place to find terminology and methods used etc for further research.
1) each metre interval is logged and bagged separately. These are not accurate metre intervals though. Eg. A drill string is 6 metres. So some crews May just gather a huge pile of chips for that 6 metre stretch, and then divvy it out into 6 heaps. Even if you keep an eye on the depth of the hole as it is being drilled, metre by metre, by the very nature of the way the chips are returned to surface, you can get cross contamination of the chips (weight, lithology, grain size, depth, casing can play a part)
2) hole diameter is on a case by case basis. Depth of hole and aquifers are the main consideration.
3) rc is good for scouting or first-pass drilling. Once you get a solid sense of the geology, and are able to predict where your veins or target zones are, you can then use a combination of rc and diamond. Eg. Your target zone is say, 250m to 300m. You would then normally rc to say 240m, then diamond drill to the end of hole. It's brilliant in that sense (3or 4 days saved), provided you don't accidentally rc drill your target and have to redrill the hole! Geology can be a fickle mistress at times!