The planned programme was very clear about drilling the diamond core first to understand the geology/structure and then using the information gained to guide the location of the aircore holes. I recently posted on a CNB thread about whether geologists can tell if a hole is good before assay results are received. My recent post will give you a bit of background and context and might be worth a read (3/5/21). I said "if you drill the alteration and mineralisation that generally equate to ore grade in the area then you can state that the hole might be good. CNB are just getting their eye in at Strelley."
The diamond drill holes found the sulphide mineralised intrusive that looks very similar to Hemi. Now the geologists on site would not have assays but it is fair to say that sulphide rich intrusive that look like Hemi would have got people pretty excited. As Alfie Knows said today, "I can tell you that the significance of this is not in the concentration of gold, it is the location of intrusion hosted gold mineralisation. I can also tell you that it is not too early to compare, in fact - it is the only comparison to De Grey's "Hemi" on earth at the moment. Very significant development in the story of Pilbara gold."
CNB would have been able to look at the surface geology, geophysical and soil sampling signatures for the location of the intrusive they drilled. By then looking elsewhere in the CNB ground for similar geology, geophysical and soil signatures drilling targets emerge. Previous drilling would be considered as well. I suspect they knew exactly what they were looking for but some extra drilling locations would have been added and drilling orientations adjusted as necessary. Downhole geophysics and camera work may have been used too.
CNB located more intrusive bodies such as Conway and then put a diamond hole into it and aircore holes too. Two previously inferred intrusive bodies were also drilled.
They would have been logging the aircore holes as they progressed and adjusted locations accordingly to test preferred zones. The aircore lines are still very widely spaced and not definitive, you can get a big ore body between the lines.
The RC drilling which is about to start will be the real test because of the larger sample size and depth that can be tested. Aircore tends to be very shallow and is used as a guide for where to put the real holes (RC, Diamond). The aircore gold results will help guide the RC drilling locations but unless they are really good they don't make or break this area. Not too many people will walk away from an intrusive on this ground without putting deeper RC or diamond holes into it, the potential prize is too great. Deeper RC holes will be important if there is any chance of leached zones or supergene enrichment.
The announcement does not give enough information to comment on the second drill hole. However you need to have a certain percentage of holes which are outside the mineralisation to ensure that you have determined its geometry and extent. I am not sure that was their intent here but I am sure it gave some useful geology and structural information. It told them that the gold was not in a particular rock type and structural setting and may have helped to direct the drilling a bit.
CNB Price at posting:
34.5¢ Sentiment: Buy Disclosure: Held
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