RE: Tip eatlier last year21 Feb 2021 11:51
From John Cornford article..
…..Bushranger contains the Racecourse deposit which, so far, has delivered an inferred JORC resource of some 690,000 tonnes copper equivalent……
I queried the 690,000 tonnes copper figure when this was first stated by Cornford in his article. The current guidance is for 310,000 tonnes copper (71mt x 0.44%) at 0.3% cut-off.
So why is a much higher figure being stated and contrary to the official figures?
I think it was James' who said the 690K figure may be because a much lower cut-off % than the 0.3% was being used. That makes sense and is probably correct, as we know the resource substantially increases by circa 50% when a 0.2% cut-off is used rather than 0.3%. Obviously it increases further when the lowest economic 0.15% cut-off is used.
I wonder if the 690K tonnes figure is against the lowest economical cut-off point of 0.15%??
Just a guess. But I think that’s a reasonable assumption,
IF so, that puts our resource at 0.69mt IF POC gets to $10K and the 0.15% cut-off can be used.
Obviously, that’s before any increase is factored in due to drilling.
My understanding is (I may be wrong) that the resource has already been increased by circa 50% on two of the dimensions. IF all three dimensions can be increased by circa 50% then I think the resource should increase by circa 3.375 times.
ie 2x2x2 = 8 50% increase of 2 = 3, so 3x3x3 = 27. 27 is 3.375 times greater than 8.
I know the resource will not be a perfect cuboid but the above gives an illustration of resource increase as the 3 dimensions increase..
So IF POC gets to $10K this year we could then use 0.15% cut-off. And assuming the third dimension increases by 50%,(like the other two), it could be argued that the resource would then be 2.33Mt (690K tonnes x 3.375).
To be clear, this requires POC to get to $10K and the third dimension to increase by 50%, which has not yet been confirmed. But I think the odds are better than 50/50 that those two things will happen imho.
Even if we don’t increase the third dimension at all (unlikely) , the volume should have already been increased by x 2.25 (2x2x2=8) (3x3x2=18) 18 is 2.25 greater than 8. That would put the resource at 1.55mt (690K x 2.25).
If we are very pessimistic and use the higher 0.2% cut-off (POC over $7500) and not 0.15%, the original 0.31mt resource at 0.3% cut-off increases by circa 50% to 0.465mt. Multiply this by 2.25 and we are at just over 1mt. That’s without the resource increasing from any new drilling results and using 0.2% cut-off – which we can reasonably do as POC is over $7500 .
So it looks like we are at 1mt now, and will probably go to at least 1.5mt after all drilling completed. Subject to drilling results, POC, and a bit of luck, we may go to just over 2mt.
Of course AIMHO
Others will have different views