I showed my working copy of this to TR and GJ and they gave some broad comments about how they see things shaping up which I have added to some of my previous research.
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The 3 faults (
F) shown in purple seem to be quite important.
The main NW-SE one marks the western side of an up faulted block that could host significant open pit ore.
The fault near hole 72 came as a pleasant surprise, I believe, and the small down faulted block to the NE should add a nice sweetener to any open pit. Will be interesting to see assay results for Holes 130, 131 and 133.
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Main sections for open pit option are 5 and 6 (for location of sections see the messy image above). Section 4 shows the near surface mineralisation appears to stop to the NW.
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Back of the envelope tonnage calculation for the 5 areas outlined on the first messy diagram:
Assuming a 4m average thickness and Specific gravity of 3.
Area 1 350X150m for some 600,000 tons
Area 2 Triangular 200X120 perpendicular for some 160,000 tons
Areas 3 and 4 both about 100x50m for 60,000 tons each. Glenn J suggested I may have under estimated these blocks.
Area 5 depends on grade/thickness in Hole 117 which if positive would suggest some 100Kt. More drilling is required to define a resource in this area and see how far it extends to the West and North.
These figures show that drilling to date may give a very speculative resource of around 1Mt for Opasura east. Of this two blocks ((Part of #1 and all of 4 )~200Kt +-) may be open pittable.
As mentioned before the underground portions should be amenable to mechanised room and pillar mining with a minimum 'height' of 2m.
Access is possible into the historical adits and stopes where ground conditions today suggest good geotechnical ground stability. That is they have not collapsed over the last 40 odd years - "We could hold this GM in there" to paraphrase ?TR.
Average grades probably in 5-10% range combined Zn+Pb with hopefully 8-10% at least for a final grade.
The above calculations basically ignore a lot of variability for thickness/stacked lenses (not considered)/SG and grade but IMO show that this section of the deposit could be economically viable. Judging by comments at the meeting and from Gaucau
should rather than could....wait for PEA/DFS.
AZS have noted variations in Zn/Pb ratios in the drilling but not clear how significant they are at present.
Some very speculative figures in here so DYOR.
