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Gold/Mining/Energy : International Precious Metals (IPMCF) -- Ignore unavailable to you. Want to Upgrade?

To: GlobalMarine who wrote (27847)	11/20/1997 2:30:00 PM
From: Richard Mazzarella	Read Replies (2) \| Respond to of 35569

Rand, we have been told before that the ore is fairly homogeneous, now we are hearing a different song? Looking at reported results from Maxam, GPGI (not the ore pile), GTH.V, IPM, and others, there seems to be general deposits in that region of 0.04-0.05 OPT Au. However, one can't discount higher concentrations of metal, i.e. Maxam's pluton. I also know that Maxam ore that assays 0.05 can be "worked" to release higher values. Maxam experiments (uneconomical recovery?) have shown values of 0.2-0.3 OPT Au recovered from 0.05 Au assayed dirt. This story isn't over by a long shot. PS, I went though this stuff again for Chuca.

To: GlobalMarine who wrote (27847)	11/20/1997 2:33:00 PM
From: Tim Hall	Respond to of 35569

The sample contains a finite amount of gold. If a fire assay procedure works, it should be able to analyze close to the same amount each time. This will however depend on a number of different factors inlcuding but not limited to procedure, who does it, how accurate scales, how closely procedure followed etc. After a number of these are run on the same sample, an average should develop. Then depending on the accuracy desired, the standard deviation determines how many times this sample must be analyzed to determine average. Larry is right, this is not a comparable situation to flipping a coin. I would like to see the actual report from the lab/consultant/ipm/whoever, where this procedure is discussed and what repeatable accuracy they were looking for and how they determined it. Tim Hall

To: GlobalMarine who wrote (27847)	11/20/1997 3:17:00 PM
From: Bob Jagow	Respond to of 35569

More to the point, you get the same result twice 50% of the time.

To: GlobalMarine who wrote (27847)	11/20/1997 8:28:00 PM
From: E. Charters	Read Replies (1) \| Respond to of 35569

Students T test or chi nova or any stats test that compares variances of two groups of assays is used to compare assay houses or groups or different labs on pulps or rejects. Because of the huge variability on heads or coarse rejects you would need at least 100 samples to compare results on splits of coarse samples. Fine pulps SHOULD have close comparisons. RE-assay of pulp should come to 95% of first split. The mean of any split group (or two groups of the same material) will be close even if one lab is horrible. The best method has the smallest variance. That means if the sample to sample variance on a whole group is least then it is likely that random problems in methods also have the least input. Capiche? So if one guy is getting from one ounce to .01 and the other .04 to .50 then the latter is preferred. Now compare the two groups with a T test. The T test tries to determine if they are the same group by comparing variances, and assumes measurement errors crept in. If the T test shows the two groups are 95% probable the same group then the assays from both labs are comparable. Another way to do it is to combine two assay groups, if the variance changes drastically then we have a problem. The Variance is got from subtracting the mean or average from each value and squaring it. You then take the average of all these squares. The square root of that is the standard deviation. Within two standard deviations on each side of the mean should be 66% of all your assays in any one group. Normally.