Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Gold/Mining/Energy : Gold and Silver Juniors, Mid-tiers and Producers -- Ignore unavailable to you. Want to Upgrade?

To: Mario :-) who wrote (15118)	7/4/2006 12:56:36 PM
From: E. Charters	Respond to of 78419

The structures that are dilatorily permissive to gold solution emplacement often get my heart beating tippy-tap, tippy-tap. Although most people would think that I am saying I told you so, when I first looked at the Bre-X drill core, which was a tight sandstone with dull pyritic and Pb veins in it, I remarked that it seemed like the strangest, driest rock I had ever seen that had gold in it. Although this is true, I dropped suspicions along with everyone else when the results kept coming in (the big lie). Normally you need alteration minerals, and good-looking, sheared rock, with plenteous quartz and carbonate (the fizz when you add drugstore HCl) to get gold. Some iron and copper, Pb does not hurt either. Potash mica is abundant as sometimes is biotite, talc, and or tourmaline. The old standby is brownish or whitish sericite. But some gold rock is remarkable dry looking. Timmins and Beardmore may be cases in point. timmins looks dry and assays dry 90% of the time. No gold. Bull Quartz looking veins. But is rich in total ounces and has the porphyry like the dickens. In Geraldton Beardmore, the bigger the vein sometimes the better. A mass of crenulated (twisted and folded) dry-looking quartz the size of a house is just dandy. But small wiggly veins, just like the barren kind in the migmatite in that picture, can bust out with high grade galore in the Lake Nipigon camp. The rules are so varying and the exceptions so common the adage that gold is where you find it can be almost taken literally, but most are not fooled who in gold are well schooled. You have to have something that "talks". Shearing, quartz, accessory mineral, or some lead that looks rich. It is not always the same. Sometimes it is iron and rust and shear, sometimes quartz-carbonate all over the place, sometimes alteration of the host rock, although a drier host is preferable often. But there is always something giving a clue. Veins that surged in at greenschist temperatures have to tell a story, and if you look close enough the minerals will squeak "pick me, pick me", with tiny, but strident voices and the prospector will swing his rock hanmmer with the confidence borne of experience and age. Alteration packages differ from place to place. the alteration of the Nevada desert or Peru is different from Canada. We don't get much Roscoelite up in these parts. You look for different things. But one thing I have found is that what you find that associates with gold stands out. The anomaly to the practised eye is just that. You may not know what it is at first, but you know it's something. em.gov.bc.ca cim.org "Coarse gold-bearing veins are characterized by high grades that are localized and erratic. Effective sampling of coarse gold-bearing veins is difficult because of the low concentration and erratic nature of the gold particles. Diamond drilling is an effective measure of geological continuity, however, grade distribution can only be reliably obtained from underground development (including close-spaced sampling, bulk sampling, and trial mining). Comparison between surface and underground drilling, underground linear/panel and bulk sampling indicate that drilling and linear/panel samples generally understate bulk sample grades. Bulk samples are likely to be the closest estimators of true grade. It is unlikely that anything above an Inferred Resource category can be estimated from surface drilling alone, and at best the grade will only be a global estimate. Underground development, in-fill drilling and bulk sampling/trial mining will be required to delineate Indicated and Measured Resources. Closely spaced development and bulk sampling is likely to be the only way to determine Reserves. The resource estimation process must driven by a clear geological model that should attempt to understand both geological and grade continuity. Traditionally, grade interpolation has been undertaken using classical methods, though more recently, computer-based block modelling techniques have been used with some success. Three case histories are presented, documenting the problems of estimating resources in coarse gold-bearing veins and the practical ways in which they were approached." EC<:-}