RE: RNS3 Nov 2021 11:51
It's hard to say a decent grade for individual metals on a polymetallic structure. The way I tend to work it is by creating a composite tonnage value (which the copper equivalent does, but that is only valid at the stated prices and is irrelevant if there is no copper in that section).
If you take the last reported intercept today as an example, it contains: - 0.56% Copper, 0.24% tin, 8.99% Zinc and 27.1g/t Silver.
That means that 100t of that material will contain 0.56t of copper, 0.24t of tin, 8.99t of zinc and 2710g (90troy oz) of silver
If you take the metal prices (or whatever figure you want to use): -
Tin - $37,000
Copper - $9,700
Zinc - $3,400
Silver - $22/oz
That means that 100t of material will contain: -
Tin - $8,880
Copper - $5,432
Zinc - $30,566
Silver - $1,980
For a total composite value of $46,858/100t or $468.58/tonne.
Bearing in mind this will be a narrow vein operation, with increased dilution, you would want to allow around $120/tonne mining cost.
Mill recovery is likely to be in the region of 70% - polymetallics have a lower recovery than single element mills.
As a result it probably wouldn't be worth mining material worth less than $250/tonne.
Nb these are all very hi line figures in lieu of any PEA or FS.