You are right about the complexity, but Lac des Iles is classified as a magmatic nickel-copper-PGE deposit by the GSC, OGS etc. The PGEs are concentrated in and at the margins of a pegmatitic gabbro dike. There is some associated mestasomatism- an irregular zone of alteration which is associated with the intrusive event but the PGEs are there as a result of the magmatic event. PGEs have only been seen to date to be concentrated to mineable grades in the earth by magmatic processes. The area is highly deformed- there are many faults. The reconcentration in the breccias is not hydrothermal, but partial remelting. The paper of choice for the mineralization model is:
Brugman, G.E., Naldrett, A.J., Macdonald, A.J. 1989: Magma mixing and constitutional zone refining in the Lac des Iles Complex, Ontario: genesis of platinum group element mineralization; Economic Geology, V.84, p.1557-1573.
I have a copy of the paper in front of me and I can provide more details if you want, but for what purpose <g>.
The new reserve is 71.9 million tonnes at 2.09 g/t (PGE+Au) based on a cutoff of 0.85 g/t Pd at $320 an ounce. From what I have gathered in the news releases, this is based on 100 foot drill centers (30 meters). The high-grade shear zone material, from what I gather, is beneath the main mass. You can look at the sections in the following news release:
sedar.com
There does not seem to be much of a problem with the ore distribution above the 0.85 g/t cutoff- seems pretty uniform. On 100 foot centers, I do not foresee a problem with the reserves, unless of course Pd goes to $300- an ounce.
From the PDL site:
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Total cash costs over the mine life, net of other metal credits and including royalty, are estimated at US$160 per ounce of palladium.
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I think PDL is sitting pretty on this one <g>.
Bruce |
