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 withi ........

The 777 mine was closed on schedule, in June 2022, after 18 years of steady production.


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 h ........

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