Lac des Iles Mine
Location: Toronto, Canada.
Products: PGE Deposits.
By product: Gold. Platinum, silver, nickel, and copper.
Owner: North American Palladium Ltd.
GEOLOGICAL SETTING AND MINERALIZATION
The Property is underlain by mafic to ultramafic rocks of the Lac
des Iles Intrusive Complex in the Wabigoon Subprovince of the Canadian Shield.
The LDI-IC is an irregularly-shaped Neoarchean-age mafic-ultramafic intrusive
body having maximum dimensions of approximately 9 km in the north-south
direction and approximately 4 km in the east-west direction. The complex
incorporates three discrete intrusive bodies viz.:
The North Lac des Iles Intrusion (NLDI) characterized by a series of
relatively flatlying and nested ultramafic bodies with subordinate mafic rocks.
The Mine Block Intrusion (MBI), host to all of the stated Lac des
Iles mineral reserves and resources (refer to Sections 14.0 and 15.0).
The South Lac des Iles Intrusion (SLDI), a predominantly mafic (gabbroic)
intrusion having many similarities to the MBI in terms of rock types and
textures. To date, NAP’s exploration activities have been focused on the MBI.
The MBI is a small, teardrop-shaped mafic complex with maximum dimensions of 3
km by 1.5 km and having an elongation in an east-northeast direction. The MBI
consists of gabbroic (noritic) rocks having highly-variable plagioclase:
pyroxene proportions, textures, and structures. The MBI was emplaced into
predominantly intermediate composition orthogneiss basement rocks. The MBI is
intersected by a series of brittle to ductile faults and shear zones, some of
which appear to control the distribution of higher-grade palladium
mineralization. A major north-trending shear zone appears to have cut the western
end of the MBI and is spatially associated with the development of high-grade
palladium mineralization. Textural and mineralogical variability is greatest in
the outer margins of the MBI, especially along the well documented western and
northern margins that host most of the known palladium resources. Commonly
observed textures in the noritic marginal units of the MBI include
equigranular, fine- to coarse-grained (seriate textured), porphyritic,
pegmatitic, and varitextured. Platinum-group element and copper-nickel sulphide
mineralization in the MBI is found in a variety of structural and geological
settings but in general is characterized by the presence of small amounts
(e.g., typically less than 2%) of fine- to medium-grained disseminated
iron-copper-nickel sulphides within broadly stratabound zones of platinum group
elements (PGE) and gold enrichment.
The mineralization is commonly associated with varitextured gabbroic
rocks; coarse-grained noritic rocks; and local, intensive zones of
amphibolitization, chloritization and shearing. An important, distinguishing
characteristic of the MBI mineralization relative to other PGE deposits is the
consistently high palladium:platinum ratio, commonly averaging 10:1 or higher.
Sulphide mineral assemblages are dominated by pyrite with lesser pyrrhotite,
chalcopyrite, pentlandite, and millerite.
MINERAL RESERVE ESTIMATE
The mineral reserves were estimated by applying wireframe models
depicting stope and pillar shapes to the underground geological block models
provided by NAP. NAP aslo provided a separate, more historical geological block
model for open pit evaluations, as well as RGO stockpile resource information
that was used to estimate the amount of the stockpiled resource material that
would be recovered during the LOM time period and accordingly be brought into
the reserves. For the underground models, a mineral resource envelope was
established with a 1.0 g/t palladium resource grade and a block size of 5 m by
5 m by 5 m. For the open pit block model, NAP used a 2003 block model that had
a block size for pit evaluations of 15 m by 15 m by 8 m. Tetra Tech’s senior
geologist reviewed and validated each of NAPs submitted block models, prior to
use.
Mineral Reserves at the Cut‐off Grades |
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