The 777 deposit lies in the western portion of the Paleoproterozoic Flin Flon Greenstone Belt.

The Flin Flon formation is subdivided into three mappable members containing units of heterolithic and monolithic breccias, rhyolite flows and domes, and massive and pillowed basalt flows and flow-top breccias. It is comprised of the Millrock member, which contains the 777 and Callinan mineralization, and in footwall to it the Blue Lagoon and Club members.

A complex succession of felsic and basalt-dominated heterolithic volcaniclastic rocks host the Flin Flon Main, Callinan and 777 VMS deposits within the Greenstone Belt. The north-trending, VMS-hosting, 30 to 700 metre thick volcanic/volcaniclastic succession is recognized for at least 5 kilometres along strike and has an average dip of 60°E. The volcaniclastic rocks have been interpreted to occupy a volcano-tectonic depression within a basaltic footwall succession

The 777 and Callinan deposits occur within an east-facing sequence of volcanic rocks documented as tholeiitic and basalt-dominated, and dated around 1888 Ma. The rocks immediately hosting the mineralization, however, consist of quartz-phyric (“QP”) and quartzfeldspar-phyric rhyolite flows and quartz-feldspar crystal-lithic volcaniclastic rocks of rhyolitic composition.

The 777 deposit can be divided into two main southeast plunging trends, the North Limb and the South Limb, as well as the West Zone. All three zones lie within the same stratigraphic sequence with the same lithofacies. The West Zone lies in the footwall in what is interpreted to be a lower thrust slice and both limbs have the same stratigraphic sequence. On average the lenses strike at 010° and dip to the east at 45°. All zones have a relatively shallow plunge trending at -35° towards 140°. Horizontal widths throughout the deposit range from 2.5 metres to 70 metres in thickness, and can be thicker when two or more zones overlap.

Mineralization is generally medium to coarse grained disseminated to solid sulphides consisting of pyrite, chalcopyrite, sphalerite, pyrrhotite, and magnetite. The principle gangue minerals are chlorite and quartz. Alteration minerals include biotite, epidote and actinolite.

The 777 mine is a multi-lens orebody with shaft access down to the 1508 metre level. The mine consists of an internal ramp that provides access to each mining level. Mobile tired diesel equipment is utilized. Load haul dump (“LHD”) units vary from 6.1m3 to 7.6m3 . Trucks are 40 to 50 ton units feeding an ore pass system or direct to rock-breakers which feed an underground crusher and ore is skipped to surface via the shaft.

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.

Drilling is done by top hammer long-hole drills with holes varying in length between 10 metres and 20 metres long and a hole diameter of 3 inches. Mucking is accomplished by remote LHD units and then loaded to haul trucks.

Ore at 777 mine is loaded by LHDs to underground haul trucks, which dump to a series of ore passes that feed three chutes on 1412 metre level. Haul trucks are loaded from the chutes and haul the ore directly to the main ore pass system on 1412 metre level. The ore is temporarily stored in a 1,725 tonne coarse ore bin that feeds the crusher. From the crusher it is conveyed to a 1,600 tonne fine ore bin, where it is conveyed to a loading pocket at the 1508 metre level and placed into two 15 tonne skips and hoisted to surface. The ore on surface is hauled by 53 to 63 tonne haulage trucks directly to the Flin Flon concentrator or is dumped on a stockpile close to the concentrator.

Ore from 777 North expansion is loaded onto haul trucks by LHDs and transported up the ramp to surface. The ore is dumped on the ground prior to being sent through a surface crusher operated by a contractor. The ore is then loaded and transported for processing at the Flin Flon concentrator or stockpiled nearby.

The Flin Flon concentrator is an operating plant running at steady state, with a capacity of 7,200 tpd. The concentrator produces zinc and copper concentrates. [2019 TR, 92]

Historically, the Flin Flon Concentrator treated both Reed ore from the Reed mine and 777 ore from the 777 mine from 2014 to 2016 at a blend mix of 7:3, 777/Reed, producing copper and zinc concentrates. However, upon closure of the Reed mine in July 2018, the Flin Flon concentrator now treats primarily 777 ore and Lalor ore in batches as scheduled. [2019 TR, 92]

Flin Flon concentrator processes 777 ore into copper and zinc concentrates. Copper concentrate is sold to third party purchasers and zinc concentrate is sent to Flin Flon zinc plant where it is further processed into special high grade and continuous galvanizing grade aluminum alloy zinc metal before being sold to third party purchasers.

The Flin Flon concentrator facility includes a paste backfill plant and associated infr ........