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 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.

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 Flin Flon Concentrator is capable of producing two concentrates: a zinc concentrate and a copper concentrate with gold and silver credits. The Flin Flon Concentrator typically processes approximately two million tonnes of ore annually.