Exploration is central to the Lac des Iles (LDI) operation. Based on their structurally-controlled sub-vertical orientation, unusually large thickness and atypical, selective enrichment in palladium relative to platinum, the LDI PGE deposits are truly one-of-a-kind. In recent years, the Mine Site exploration team has significantly added to the Offset Zone resources while delivering greatly improved 3D geological models and additional mine site exploration and resource gain opportunities. These exploration successes give management great encouragement that continued exploration investment will not only maintain but will lead to the growth of the mineral resources at LDI. As an established PGM producer with a clearly defined strategy for growth, NAP is well positioned to convert exploration success into production and cash flow on an accelerated timeline.
Surface projection of the principal zones of palladium mineralization on the Mine block intrusion, Lac des Iles intrusive complex. Surface geology highlights the adherence of palladium mineralization with late pulses of intrusive breccia and vari-textured gabbro, particularly along fault contacts with older, unmineralized units such as equigranular gabbro.
Longitudinal projection of the Offset and Roby zones, looking west.
Developed and planned stopes in the Offset Zone are shown in green.
Ramp development has recently reached a depth of 1,000 metres
below surface. A majority of current production is being sourced from
the Central Offset Domain between the 765 metre and 925 metre levels.
Exploration is focused below the 1065 level, at the top of the Upper
Offset Zone (southeast extension) and south of the Camp Lake fault.
Schematic cross section, looking north, showing the relative position of the Roby and Offset hangingwall and footwall zones with simplified geology and current extent of Roby open pit.
- Roby Zone: A majority of the known surface and underground hangingwall zone resources are largely mined out; retains potential for selective underground development of higher-grade parts of the undeveloped footwall zone and a future expansion of the Roby open pit to extract the remaining near-surface palladium resources primarily located around the southern end of the pit
- Offset Zone: discovered in 2001 and located below and west of the Roby Zone, underground mining of the Offset Zone commenced in late 2013 at a depth of ~600m below surface and is currently the principal source of high-grade feed to the mill; the Offset zone consists of two subzones based on differences in palladium grade, sulfide content and geology (see accompanying longitudinal projection and cross section):
- Offset hangingwall zone – located directly adjacent to the barren hangingwall gabbro, typically hosted by a schistose, altered mafic rock (‘pyroxenite’) and commonly having average palladium grades of 4 to 6 g/t over true thicknesses ranging from several metres to several tens of metres, but with ‘bonanza’ grades in the 10 to 30 g/t range over 1 to 5 metres being a common feature in the highest-grade areas
- Offset footwall zone – located west of the hangingwall zone and featuring thick, moderate grade palladium mineralization, typically averaging 2 to 3 g/t palladium over several metres to tens of metres, and most commonly hosted by vari-textured gabbro
All of the current mineral reserves for the Offset Zone are hosted within the Offset hangingwall zone that is subdivided into three discrete geological domains (refer to longitudinal projection):
- North Offset domain – featuring narrower (i.e., several metres thick), less continuous but commonly higher-grade palladium mineralization than that present in the adjacent central domain
- Central Offset domain – featuring the thickest (i.e., typically 20-30 metres thick), palladium mineralization in the Offset Zone and having the overall geometry of a south-plunging trough with a relatively planar eastern (hangingwall) contact and an arcuate, ‘V’-shaped western (footwall) contact
- South Offset domain – featuring moderate grade palladium mineralization showing highly variable thickness and continuity that bifurcates around older, barren to locally mineralized norite
- Upper Offset Southeast Extension: discovered in 2013 and recently renamed (B2 zone), this zone is located at the top of the currently defined Offset Zone resources at depths of ~350 to 700m below surface and features moderate to high-grade palladium mineralization developed at the east-west striking and south-dipping contact between vari-textured gabbro and older noritic rocks; currently being evaluated for future development and remains open along strike and at depth
- Sheriff Zone: located approximately 100 metres east of the Roby Zone with an initial near-surface resource estimated in 2013/14; drilling in 2014 identified a discrete high-grade subzone (Powerline Zone) that hosts some of the thickest and highest grade mineralization known at LDI; ongoing exploration is focused on extending structurally-controlled high-grade palladium mineralization beyond the current limits of the defined resources
- North VT Rim Zone: initial resource estimated in 2014; this outcropping, easterly-trending and south-dipping zone of palladium mineralization features very low base metal sulfide contents and is hosted within a geologically complex association of norite, leucogabbro, vari-textured gabbro and post-magmatic shear zones and dykes; the NVT Rim zone remains open at depth and to the east.