Originally posted by eastwest101:
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Its important that people posting here can discriminate between the collection of data, and the interpretation of it and what the XRF can and cannot detect. Quantitative geochemical data can be from traditional assays, and also from portable XRF, and assays can be from rocks at surface or from drill cutting samples or drill core down-hole. In general most here get it that from some target elements (Cu and Ni for instance) can be directly detected by XRF or by traditional assays with reasonable accuracy, while other precious metals cannot be reliably detected by XRF because of their rarity and stable outer electron shell (Pt Pd and Au), this is why gold explorers don't routinely use XRF's to directly detect gold in drill samples, the only way is getting a decent sample size and a real lab assay done. XRF's can detect a wide variety of metal and transition elements quite quickly and in some cases almost the same accuracy as a traditional whole rock assay, some of these elements are worthless but are associated with other more precious metals so can be "indirect" proxies or "pathfinders" for the stuff you are looking for. Elements such as As and Bi are famous for their pathfinding ability for some types of gold deposits. Its important to distinguish which types of target mineralisation at Broken Hill are visual and which aren't, in RC chips and in drill core. In high enough concentrations say between 1% and above, disseminated copper chalcopyrite and nickel pentlandite sulphide minerals are visual but often mixed up with worthless iron sulphide mierals such as pyrite and/or phyrrotite, and they would have a chance to guess the copper and nickel grades, and even confirm with an XRF before sending to the lab but for gold or PGM metals, because they are down in the parts per million range if they are occurring without base metals then they might be impossible to spot visually, and the XRF is no help with those elements either, so they would be relying on lab assays. The geochemical ratios that Mike Jones and IPT are talking about is getting a bunch of geochemical numbers form many elements of many outcrops and drill holes and looking at not only the proportion of Cu Ni Pt Au and Pt in all these geographically distributed samples but also considering other ratios of other elements that aren't particularly valuable but do give clues about the geochemistry of the rocks, say for instance the ratio of iron to magnesium, or using other pathfinders maybe such as Co V Mn etc etc and throwing all of these different ratios on scatter plots and seeing if there is a direct relationship between any of these elements and the samples from the higher grade Pt Au Ni Cu zones already drilled. Once they think they have a good bunch of pathfinder elements and/or ratios of elements that might show "prospective" rock geochemistry for mafic Ni Cu Pt Au style mineralisation then IPT can go out and collect a bunch more of geochemical data (this is where the XRF comes in handy) from outcrops, and from all the other drilling nearby, plot it up on a map and direct further sampling and drilling to these areas. The one thing you want to watch out for is you want pathfinder elements and ratios of elements that don't disappear in weathered rocks at surface, but are a bit persistent in surface rocks, otherwise you cant extend your geochemistry data set coverage onto the outcropping surface rocks. You don't want pathfinder elements that go into solution and disperse with weathering into gullies or flats or preferentially collect in some soils because you are trying to find the source of these valuable related metals, not where they get washed out into during normal weathering processes. Someone else asked about additional permitting required for additional drill holes, most state regulators now want companies to specify how many drill holes they have planned and where and if the exploration company want to drill additional drill holes then the regulator usually needs to see a new or amended proposal of additional drilling planned, nothing unusual in that but it does reduce the flexibility of companies to follow up quickly if they discover something visually encouraging and drill additional holes around it. Unfortunately most regulators now won't accept vague proposals to drill a bazillion holes "somewhere" in this area anymore, and they want specifics about hole locations and depths so when your plans change you have to submit new or amended proposals, just part of the regulators justifying their own existence. This is all reviewed and permitted by people who have never done mineral exploration, and usually never seen a drill rig in their life... I'd say what has happened here is that IPT have done their geochemical ratios and pathfinder work and want to drill some extra holes in new places and are just awaiting approval for these additional holes. Losing their big batch of assays last month mean that they are "flying blind" a bit about which of their drill holes have been successful and which have not because they have had to go back and re-sample if possible and then wait for the lab assays.
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Originally posted by eastwest101:
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I will have to look at the maps but the channels they identified were only a few hundred square metres but the drilling itself may have been spread out a bit more along strike at Platinum Springs and Plat Springs East? As I mentioned before - you cannot just draw a box around an area and say you want to drill in there anymore, that would be too easy and logical, the regulators want to know where you plan on drilling and even modest step outs say 50m or 100m along stike need to be documented and approved, Mike did mention in that interview that the NSW regulators have a special process in place for programs underway that expedite variations of drilling if the drilling locations and plans change on the ground. Not going to add to your comments about any MD salary or compensation but I have been less than kind sometimes about the rate of progress in the company in my infrequent visits to the IPT discussion boards. Regarding the loss of samples, its extremely rare in the industry to lose an entire batch of samples, I have heard of it once or twice and pallets can sometimes go missing but usually turn up days/weeks or months later in a trucking yard due to a paperwork screwup or labels and stickers falling off etc. Usually a batch will be an entire pallet or two or a sample cage, not the sort of thing that you can accidentally drop and hide down the back of a truck, you usually need forklifts to move them. Sometimes one or two samples may get lost in transit if they are mistreated or fall off or out of a shrink wrapped pallet but losing a batch of samples is very rare. With trucking companies its almost impossible to insure samples because the insurance is tricky in that the value of the samples is difficult to quantify until you get the assay results back, obviously if the samples are lost then you won't get assays to quantify your loss and make any claim. Most trucking contracts have pretty standard all care but no responsibility clauses in them anyway. Loss of samples with core is a PITA as quarter core then needs to be recut, loss of RC chips or aircore samples isn't so bad as there are usually large extra spare sample piles/bags of drill cuttings at the drill site and you can resample and send to lab again (using a different trucking company of course). I have heard of truck rollovers where field staff have been sent out to unpack and repack pallets/cages of numbered sample bags in order to get samples accounted for and sent to the lab but its pretty rare. I note that IPT 's samples were supposed to go to Intertek Labs in Alice Springs which seems an unusually long and tenuous logistic chain to a lab that isn't particularly close, but maybe that lab had special expertise in PGMs assays or something, and thats why it was chosen. Reading the Table 1 I now see that the sample prep was supposed to happen at Alice Springs and then smaller subsample pulps go to Intertek in Perth for the actual assays, but from the sound of the announcement it looks like the samples never made it to Alice Springs. In this announcement you can see the map Fig2 on page 2 seems to suggest that they are solely using XRF results in their "calculated ratio values" that they were using to vector to the particular central mafic channels, but when you look closely at that map I think you'd agree that people would want to see a bit more coverage in a systematic way of these XRF results on a map to completely convince themselves that these ratios are actually showing areas known to have enriched Cu Ni and PGMs Here are some other similar papers about people using XRF and calculated ratios to help out exploration and vectoring to particular rocks/alteration and mineralisation. For anyone who is interested about ratos of metals in different mafic rocks etc google this and have a read (can't link sorry as its a massive PDF): Magmatic ore deposits in mafic–ultramafic intrusions of the Giles Event,Western Australia W.D. Maiera, H.M.Howard, R.H. Smithies, S.H.Yang, S.-J. Barnes, ,H.O'Brien, H.Huhma, S.Gardoll.
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It’s really good to have you back here posting with that level of experiential knowledge with a very focused response, and getting insightful clarity on these matters. I appreciate it, it is very helpful going forward, thanks! The courier’s lost samples were unfortunate, and the 4 missing have been re-sampled, which means having a full dataset of information around PSD02 — going forward that’s a prudent and measured call by the IPT geos — and the extra holes drilled at both Plat Central and Platinum Springs East will only assist further with those determinations. It looks like they reached the full allotment of holes within the current approvals, as well as hitting the planned budgetary requirements, and with an expedited pathway for further drilling, I find it very encouraging that IPT are ploughing forward and doubling down at Broken Hill honing in on those channels and re-entrant structures. I will be delighted to follow up on that link to the magmatic ore deposits in mafic–ultramafic intrusions in WA, as I’ve been looking at some fairly ancient reports from around Broken Hill that have not been very relevant to Platinum Springs.
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