To: Mike Gold who wrote (11512 ) 7/29/1998 6:46:00 PM From: E. Charters Read Replies (4) | Respond to of 34075
There have been placer gold grades of that tenor and higher. They invariably refer to the basal formation a metre or so thick and are very non-continuous. IF you tried to convince me that a 100 metres or so several miles long were running that I would quietly hand you a shovel and walk away. Thoughout the world there are volcanic, sedimentary and intrusive deposits of gold and they are comparative in grade whether they are concentrations from earlier deposits (South Africa, California, BC, Russia) or primary concentrations related to intrusives, (Spain California, Canada) or secondary deposits that were originally hydrothermal (Pacific Rim, South America.) The highest grade deposits such as Gold Strike, Nevada register phenomenal grades of gold for many tons (700.0 ounces gold in Nevada for the first 500 feet in depth.) These are mesothermal deposits. So we have many hundreds of years experience to draw upon to refer the grade of a deposit to its size and other factors. If you automatically want to draw inferences about size and grade you are going to get a pile of doubt without the other factor of proof being there. Statistical relevance of your sample size. Geological inference or not, we must know, type of deposition, number of samples and variability of samples to draw a conclusion. If it is a true sedimentary formation then I will tell you that average grade could be remarkably variable as well as the thickness of the formation. It then requires hundreds of samples to determine. If it is a hydrothermal breccia its extent would be limited by the structure. We do not have a definitive picture of any of these necessary factors so it is hard to say. echarter@vianet.on.ca The Canadian Mining Newsletter EC<:-}