777 is located within the Flin Flon Greenstone Belt (FFGB) in the Canadian Shield, one of the world’s largest exposed areas of Precambrian rocks. Within the Canadian Shield are large, deformed remnants of ancient volcanic-sedimentary terrain known as greenstone belts, which historically have been proven locations of base and precious metals.

The orebodies of the FFGB occur in a highly prospective early Proterozoic island-arc assemblage that stretches for an exposed length of 250 kilometres east-west and 75 kilometres north-south. The deposits are copper-zinc VMS type, rich in gold and silver, and hosted in both felsic and mafic volcanic rocks, with the felsic type hosting the largest deposits. VMS orebodies in the area have ranged in size from less than 100,000 tonnes to more than 60 million tonnes.

The Lalor VMS deposit is flat lying, with zinc mineralization beginning at approximately 570m from surface and extending to a depth of approximately 1,160m. The mineralization trends about 270° to 310° azimuth and dips between 15° and 30° to the north. It has a lateral extent of about 900m in the north-south direction and 700m in the east-west direction.

Sulphide mineralization is pyrite and sphalerite. In the near solid (semi-massive) to solid (massive) sulphide sections, pyrite occurs as fine to coarse grained crystals ranging one to six millimetres and averages two to three millimetres in size. Sphalerite occurs interstitial to the pyrite. A crude bedding or lamination is locally discernable between these two sulphide minerals. Near solid coarse grained sphalerite zones occur locally as bands or boudins that strongly suggest that remobilization took place during metamorphism.

Reed hosts a volcanogenic massive sulphide deposit that precipitated at or near the seafloor in association with contemporaneous volcanism, forming a stratabound accumulation of sulphide minerals. Volcanogenic massive sulphide deposits typically form during periods of rifting along volcanic arcs, fore arcs, and in extensional back arc basins. Rifting causes extension and thinning of the crust, providing the high heat source required to generate and sustain a high-temperature hydrothermal system (Franklin et al., 2005).

777 mine
Long-hole open stope is the mining method used at the 777 mine. Mine sequencing involves primary, secondary, chevron and longitudinal retreat stopes that are either paste or unconsolidated loose waste rock backfilled. Long-hole stopes are mined at 15 metre to 17 metre vertical sill to sill intervals. Stope strike lengths are generally 16 metres with widths of 2 to 100 metres, with an average of approximately 20 metres. The ore is undercut at the top and bottom of the block, providing access for drilling and mucking.

Lalor mine
Mining methods at Lalor that are currently in use or planned in the immediate future include: mechanized cut and fill, post pillar cut and fill, drift and fill and longhole open stoping (transverse and longitudinal retreat).

Ore is mucked using Load Haul and Dump (LHD) loaders which are operated remotely in inaccessible areas. The ore is then loaded into underground haul trucks or ore passes and transported to the ore handling system at the production shaft for hoisting to surface.

Reed mine
Underground longhole stoping was chosen as the mining method for Reed because of the steep dip of the mineralization and good quality of the ground.

Ore produced at the 777 mine is transported to Hudbay’s Flin Flon concentrator for processing into copper and zinc concentrates. Copper concentrate is sold to third party purchasers and zinc concentrate is sent to Hudbay’s Flin Flon zinc plant where it is further processed into special high grade zinc before being sold to third party purchasers.

The run of mine material will be transported by ttruck directly to Flin Flon where it will be crushed to less than 150mm prior to concentrating. Further testing is required to determine if the Reed mineralization will be blended with 777 Mine ore or batched independently. If batching is necessary the material will be stockpiled prior to concentrating.

Concentrating and processing of the mineral resource will be done at the Flin Flon Concentrator, which is capable of producing both copper and zinc concentrates. Due to the relatively low zinc grade for the Reed deposit, the plan is to only produce a copper concentrate with gold and silver credits.