The mineral title to the MM (previously Makwa-Mayville) property is held via several blocks of mining claims (Mayville on the north arm of the Bird River Belt and Makwa on the south arm) and a mineral lease over the Makwa Nickel deposit.
The Grid Metals, through its wholly owned subsidiary Global Nickel Inc, owns a 100% interest in the Makwa property.
The Grid Metals directly owns a 60% interest in the Mayville property. An additional 29% interest in the Mayville property is held through the Grid’s 72.56% interest in Maskwa Nickel Chrome Mines Limited, a company which holds the remaining 40% interest in the Mayville property.
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Summary:
Mineralization
Makwa
Four styles of mineralization on the Makwa Property are summarized in Ferreira et al., 1999 and some smaller mineralized showings are discussed in Juhas, 1973:
1. Magmatic nickel-copper mineralization.
2. Sulphide iron formation nickel-copper mineralization.
3. Sulphide iron formation copper mineralization.
4. Chromite mineralization.
Makwa Nickel-Copper Deposit
The Makwa deposit consists of disseminated pyrrhotite, pentlandite, chalcopyrite, and pyrite in an ultramafic peridotite layer at the base of the BRS (Ferreira et al., 1999; Harper, 2004). The higher-grade mineralization near the footwall contact contains approximately 15% disseminated sulphide minerals. About 12% of the sulphides contains nickel.
Dumbarton Deposit and F-Zone
Sulphide iron formation containing nickel and copper was mined at the Dumbarton deposit and F-Zone, both part of the Makwa mineralization. The iron formation contains pyrrhotite rich sulphide and chert layers. The widest and highest-grade sections of the deposit occur adjacent to both sides of a 60-m long gabbro plug that intruded into the iron formation. Nickel and copper grade-thickness contours suggest that mineralized shoots plunge steeply to moderately to the east and that the F-Zone probably had higher copper grades and much lower nickel grades than the Dumbarton deposit. The mineralization consists of massive and near massive pyrrhotite, pentlandite, and chalcopyrite interspersed with mafic material and magnetite.
Chromite Mineralization
The chromite occurs as stratigraphic layers up to about three metres thick at the transition from ultramafic to anorthositic gabbro at Makwa. In 1943, Bird River Chromite drilled nine holes totalling 894 m over approximately three kilometres of strike length and intersected grades up to 27% Cr2O3 over one metre. The chromite layers may also have potential for nickel, platinum, and palladium.
Other Mineralization
Other mineralization at Makwa, including the Cup Anderson, Beaver and Wento copper sulphide showings, and the 1987 gold intersections, was described by Juhas, 1973 and is summarized in Evans, 2005 and Jacobs et al., 2007.
Mayville
Nickel-copper sulphide mineralization at the M2 Deposit is hosted by a leuconorite unit sandwiched between two heterolithic ultramafic breccia units, and just below the structural hanging wall mafic metavolcanic rocks of the Lamprey Falls Formation. As noted in the Property Geology section, the Mayville Intrusion lithostratigraphic sequence is overturned and north facing, therefore, the structural hanging wall rocks represent the lower contact of the Mayville Intrusion.
Deposit Types
Four deposit types have been identified in the Project area; these are as follows:
1. Magmatic nickel-copper-platinum group-metals (PGM) sulphide deposits.
2. Magmatic chromite deposits.
3. Magmatic PGM.
4. Lithium-cesium-tantalum (LCT) pegmatites.
Magmatic Nickel-Copper-PGM Sulphide Deposits
This is the dominant deposit type in the MM Project area encompassing both Mayville and Makwa where the mineralization is associated with differentiated mafic/ultramafic sills. Nickel and copper are the main economic commodities with lesser contributions from cobalt, palladium, platinum, and gold.
Magmatic Chromite Deposits
At Makwa, chromite occurs as stratigraphic layers up to three metres thick at the transition from ultramafic to anorthositic gabbro. In 1943, Bird River Chromite drilled nine holes totaling 894 m over approximately three kilometers of strike length and intersected grades up to 27% Cr2O3 over one meter.
Magmatic PGM
Mustang drilling on the Mayville Property intersected a zone of platinum-palladium mineralization hosted in ultramafic rocks. Drill hole MAY-11-07 intersected 41.1 m at an average grade of 2.9 g/t Pt+Pd including 9.5 g/t Pt+Pd over 9.1 m. Follow-up drill holes in 2011 intersected the zone along strike. Additional drilling is planned to properly define the PGM zone.
LCT Pegmatites
A series of spodumene-bearing pegmatite dykes (Donner Lake pegmatite field) occur in the greater Mayville area, especially in the central part of the Donner Lake property. These pegmatites are related to the pneumatolytic and hydrothermal phases of the magmatic consolidation process, permeating the contact between the granites and the embedding rocks – in this case mafic metavolcanic and gabbro intrusive units. The deposits belong to the Rare-Element (low temperature and pressure) pegmatites of the LCT (lithium, cesium, and tantalum) type. As the name suggests, these pegmatites are characterized by the abundance of lithium, with cesium and tantalum to a lesser extent. Other co-products are tin, beryllium, rubidium, and silicon.