Summary:
The Bracemac-McLeod deposits comprise a cluster of polymetallic VMS lenses. All shallower deposits are mined-out and only the McLeod Deep lens remains.
The PD-1, Caber / Caber Nord deposits are part of the Matagami camp. Deposits are a polymetallic VMS of the same age and derived from the same ore forming hydrothermal system as the rest of the Matagami camp deposits.
Mineralization - Bracemac Deposits
The Bracemac deposit comprises three distinct lenses, Bracemac KT (BKT), Bracemac Main (BRC) and Upper Bracemac (uBRC), forming a stacked sequence interpreted as resulting from reactivation of an hydrothermal system along a synvolcanic structure following deposition of the Wabassee Group hanging wall basalts.
Upper Bracemac Zone
The uBRC is a small tabular lens oriented approximately N130° and dipping at -62°. The upper part of the lens is probably coming to surface under 30 to 35 m of overburden. The longest axis of this orebody is about 150 m long, plunging to N275° / -45°, and the shortest about 75 m long plunging to N150° / -45°. The uBRC lens is roughly located 80 m over the BRC zone.
The sulphides of this zone are semi-massive and count for 35 to 50% of the rock, the rest being mostly basalt, tuffite, magnetite, black chlorite (Chl), quartz (Qz) and calcite (Cal) veins. Typically, the zone is composed of 20-25% sphalerite, 15-20% pyrite, 15-20% pyrrhotite and 2-3% of chalcopyrite.
Bracemac Main Zone
The Bracemac Main zone (the designation has later been shortened to Bracemac - BRC) is a flat shaped body oriented at N093° and inclined at -74°. Its longest axis is over 225 m long and is plunging through N250° / -50°. Its shortest axis is 130 m long, plunging at N110° / -40°. The BRC zone is 80 m under the uBRC zone and more than 300 m over the BKT zone.
The BRC massive sulphide zone is copper rich, and has a Zn grade lower than typical Matagami deposits. Gold values stand in the order of 0.2 to 0.5 g/t. The sulphides are finely laminated and mainly composed of pyrite and pyrrhotite (30-70%) with sphalerite enriched intervals and chalcopyrite-magnetite zones.
Bracemac KT Zone
The Bracemac KT (BKT) zone is formed of two parts with irregular shapes, starting near surface at less than 200 m, down to over 600 m. The upper portion of this orebody is a flat shaped disk with a thick center and thin edges dipping at -45°. The lower portion is an elongated and narrow branch dipping at -65°. The upper part is zinc rich; the lower part is copper rich.
The upper part of BKT was followed laterally over 275 m and vertically over 200 m. Its upper end is bordered by a late coarse grained dacitic intrusion; the lower end is limited by a syn-volcanic fault. The lateral extensions are progressively reducing in thickness. The core of the deposit intersected in holes 46 and 47 is over 20 m thick, and the rim thickness rapidly diminishes to between two and four meters. As previously mentioned, this bed is dipping at a low angle, between 40° and 45°. The alteration is extensive under the sulphides in the Watson Lake rhyolite in this area. Strong chloritisation is observed throughout the unit with localised pipe alteration directly under the zone, along the synvolcanic fault and towards the lower part.
Spectacular zinc concentrations were intersected in this zone. The most significant one is the interval crosscut in hole BRC-07-46: 23% Zn over almost 20 m, including 41.25% Zn over 3.4 m. On the western end of this KT mineralization, a series of subeconomic intervals were also intersected in a stringer zone, about 25 to 40 meters under the KT or the massive sulphides.
The main sulphides intersected in the upper part of BKT are sphalerite and pyrite with locally (specially in hole 47) chalcopyrite, pyrrhotite and galena. The lower part of BKT is elongated in the direction of N200° / -60,-65°. This is a narrow arm (25 to 50 m wide), containing copper and zinc rich sulphides, that has been followed over a distance of 300 m from the vertical elevation of -350 m down to -600 m.
Mineralization – McLeod Deposits
The McLeod deposit area is probably one single broad mineralized area with, so far, three main centers of mineralization identified: McLeod zone, West McLeod and Copper Stringer.
The McLeod deposit is a stratabound and extensive deposition area at the KT interface. It forms a 600 m side’s triangle when considering the extremities of West McLeod and McLeod zone. The present delineation program was concentrated on the mineralization above 600 m for the McLeod zone. However, the drillholes have been extended to intercept the Copper Stringer zone about ten to fifteen meters beyond McLeod Zone. The lower part of the McLeod Zone, the West McLeod Zone, remains classified as Inferred resources. In addition, the 2010 exploration program defined a new zone named McLeod Deep, located directly under the McLeod zone, and presumed at the same stratigraphic position. The McLeod Deep zone has been categorized in Inferred resources as well.
The whole McLeod zone is regularly dipping at N110° / -65° to -70°. Its longest axis is over 600 m long and is plunging through N241° / -65. The three mineralization centers will be described separately even if everything indicates that they are linked together and part of the same mineralised system.