From a mining news editor commentary on the use of pXRF and how...

From a mining news editor commentary on the use of pXRF and how they shold not be relied upon.... All investors and especially those not in the industry or understand terminology should read the following carefully and understand what is being said. Agree 100% that only lab assay data results can confirm what is happening/occuring in the ground...

Dryblower on the perils of XRF and other JORC code adventuresDryblower's dog, his resident expert on exploration reporting, has been a little agitated lately because he misplaced his copy of the JORC code during the COVID pandemic.

So much happened during those happy years of long walks that it's possible that the people sitting on the Joint Ore Reserves Committee might have published updated rules which failed to be delivered to the dog's kennel.Whatever the reason for any uncertainty, the ever-alert hound put a paw on Blower's knee last week and tapped out a request to have the rules covering the reporting of X-Ray Fluorescence (XRF) sampling of drill core.That wasn't the only question about JORC rules. There were other inquiries from the dog about the relevance of rock-chip samples, something called visual results, and the growing use of excitable public relations consultants to write reports filed at disallowed.XRF first because it's been a regular cause of confusion for investors, especially the crop of amateurs attracted to the market during the boom years.Dundas Minerals is the latest explorer to fall into the XRF trap which is a shame because it might be onto something significant at its Central target in the Fraser range of south-east WA.

The issue, and it really should have been picked up by someone at disallowed (if there is actually anyone there who reads these things), started in September when Dundas reported:"Anomalous cobalt, copper, nickel and silver XRF values in massive sulphides from Central target drill chips."Readings, a key word because XRF results are not assays, were interesting with near surface highs of 2062 parts per million of copper, and 1123ppm of cobalt.Investors loved it, driving the Dundas share price up by 200% from A21c on September 23 to 66c a week later.It got better, because on October 11, Dundas reported a 358m intersection of sulphides and quartz veins, an announcement which drove the stock to an all-time high in what appears to have been a one-off trade at $1.55 - up 85c (121%) on the October 10 price.Looked at another way that $1.55 (even if an anomaly) represented a rise of 640% in less than a month. Yummy!Timing and detail are important in this exercise because Dundas actually reported twice on October 11.The first report of the 358m intersection was released (according to the ASX website) at 9.44am, the second at 7.52pm Sydney time (4.52pm in Perth where Dundas is based)What appears to have happened is that ASX asked Dundas for more detail about the XRF readings and a disclosure about the shortcomings of XRF readings which the company acknowledged by saying that XRF should not be considered a substitute for laboratory analysis.Two days later Dundas came back with a statement that the anomalous XRF readings had been "confirmed by assay results" which Blower's dog found curious because that's not the case in every sample.In one case a cobalt XRF reading of 1053 parts per million assayed at 19ppm while a reading of 1411ppm copper was assayed 619ppm and, to be fair, the results also went the other way with copper at 144ppm using XRF assaying at 232ppm.There's a lot to be learned from the Dundas experience, especially by the boys and girls at the ASX which has a representative on the JORC committee, starting with the failure to query the original September 26 report which highlighted the use of XRF from drill chip samples and the nighttime posting (for Sydney investors) on the ASX website of a clarifying report.Other examples which have recently caught the eye of Blower's dog, but not the ASX, were Auroch Minerals and Azure Minerals both reporting results from rock chip samples at their respective rare earth and lithium projects.Rock chips are a valid exploration tool for first-pass field work, but it would be interesting to know how many amateur investors understand that a rock plucked off the earth's surface, or chipped off an outcropping rock, might have no relevance to what lies beneath the surface.And then there is a report from Lanthanein Resources which last week said it had observed "highly encouraging visual results" from the maiden drill program at its Lyons rare earth project.What that appears to mean is that the company's geologist has sighted ironstone in drill material which is considered prospective for rare earths because the drilling is close to ironstone-based rare earth discoveries of Hastings Technology Metals and Dreadnought Resources.The market reacted in different ways to those reports. Azure got a significant boost with its share price rising by 5c (22%) last week to 28c (with a peak on Wednesday of 33c). Auroch rose as far as 6.5c and then fell back to 6c and Lanthanein rose to 4.1c before falling back to 3.7c.Seasoned investors have learned to read through the excitement of exploration reports and understand what's relevant and what's not.Amateurs, however, need to have technical issues explained by the company or by disallowed, preferably in a timely manner.It could even be time for XRF field readings to be sent back to the sin bin where they once were because they are not assays, just a handy tool for geologists - not investors.