It was great that they included most of the drilling data in the press release, and from that I have been able to model the mineralization (Leapfrog Model here):
Not in the same scale as Kamoa, but a start.
Assumptions: These are based on the data used in the Kamoa PEA
Cut-off: 1% Cu
Specific Gravity: 2.8 to 2.9 depending on the Cu grades (the more Cu, the higher the SG)
- 800m (Kamoa PEA) but
- I've also included a 1600m range to match the 'limits' used in the various maps that are found on the Ivanhoe website.
Unfortunately, there appear to be some post-mineral mafic intrusions that appear to truncate the down-dip extension of the >3% Cu mineralization. The good news is that the at the eastern and western limits of the drilling they are still intersection >2% Cu mineralization over moderate thicknesses (2-5m).
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| Mafic units in green - I'm assumed that they are approx. vertical cylinders, which is probably wrong |
It will be interesting to see if the Cu horizon continues beyond the intrusions, but if it does, it will be at ~700m depths. There have been a few holes drilled up-dip, but they have returned intervals grading <1% Cu.
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| Green Unit = Mafic intrusion; thin red unit = Cu bearing horizon. |
However, I'm going to guess that my 'estimate' will be low. I've made a few annotations on the plan map above where there is a bit of "artistic license". You'll see how the influence of the low grade intercepts are being reduced to cause the smallest of ripples on the sea of high-grade mineralization that Ivanhoe want to show. It will be interesting if this 'interpretation' continues into the initial resource estimate or if the holes are treated a but more equally.
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| correction: it should read 800m DIAMETER around each DH |
I don't think Ivanhoe have reduced the influence of the low grade deliberately. In resource estimation this is very common. The higher number of high grade intercepts tend to swamp the much fewer number of lower grade intercepts. This happens with any numerical averaging estimation technique. One way of mitigating this is to restrict the search so less holes are used, this should give more influence to the low grade locally.
ReplyDeleteIn the image they do to a degree. Lot at the ~1.5km zone of >2.5% Cu. They have a couple of holes that assayed >1.5% Cu, yet their 'zone of influence' is only on the order of ~100m.
DeleteInteresting deposit. Reminds me of the Tschudi deposit in N Namibia. Relatively flat lying with mineable thickness. Structurally controlled on the bottom and grade controlled on the top. Tschudi is OP though, and this one will be U/G, but looks amenable to room and pillar.
ReplyDeleteThe core looks competent...some runs have no fractures at all. Core recovery should be high. And bornite makes good concentrate!
The thicknesses appear to be good and moderately consistent. I didn't model the residual grades as we weren't given a full breakdown of the assays.
DeleteHowever, at the moment it is probably a bit small and low grade (compared to Kamoa) to be of massive interest to Ivanhoe, it will be interesting to see how much drilling they plan to do there over the next year.
DeleteIt needs a lot more drilling. 800 meters is a huge search distance.
Delete800m came from the Kamoa PEA for inferred resources. I know that Zambian Sed hosted copper deposits can be laterally very continuous, but it is a long way...
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