The KSM deposits display many diagnostic features of porphyry Cu ± Au ± Mo systems.

KerrR Zone
The Kerr Zone is centered on an Early Jurassic, north-south trending, steep westerly dipping, tabular intrusive complex. Drilling demonstrates that the Kerr Zone has an extent of 2,400 m along strike, a width of roughly 800 m, and a vertical extent of at least 2,200 m. The flattened and elongated modern morphology of Kerr is highly unusual for porphyry copper-gold deposits, which typically display roughly cylindrical morphologies. The flattened morphology and relatively elevated copper:gold ratio of the Kerr Zone distinguishes Kerr from the other deposits in the district. The surface expression of the Kerr deposit is a large and elongated, northerly trending, pyritic gossan, primarily exposed in a cirque on the northern flank of Kerr peak.

The Kerr intrusive complex is composed of a suite of northerly-striking and steeply westdipping dykes and intrusions emplaced into a sequence of rhythmically bedded siltstones, sandstones, conglomerates, and debris flows belonging to the Lower Jurassic Hazelton Group. Wall rocks adjacent to the intrusions have been hornfelsed and hydrothermally altered, but generally contain marginal metal grades. The complex is composed of an east and west limb separated by a thin wedge of intensely altered sedimentary wall rock. The west limb is up to 500 m thick, and the east limb is up to 300 m thick.

The dominant copper mineral is chalcopyrite, which typically occurs as isolated grains about 0.2 mm to 2 mm across, disseminated and clustered in quartz veins, fractures, and surrounding haloes. Bornite is present almost exclusively in the north half of the east leg, within a QABX zone containing >50% crackled quartz veins, and is accompanied by coarse grained chalcopyrite and minor tennantite. Tennantite-tetrahedrite is rare, but widely distributed in late quartz-carbonate veins, mostly in wall rocks, along with minor sphalerite, rare galena, and arsenopyrite. Visible gold has not been observed except under microscopic examinations, where it is observed as less than 100 µm inclusions within sulphides, mainly chalcopyrite, and sulphide grain boundaries.

Sulphurets Zone
The Sulphurets Zone is situated between the Kerr and Mitchell deposits, immediately to the north of the valley hosting Sulphurets Lake. The main body of the Sulphurets deposit has a lensoidal geometry, dipping approximately 30 degrees northwest. It has a horizontal extent of 2,200 m, down dip extent of 550 m, and true thickness of up to 330 m. Copper and gold grades gradually diminish towards the limits of the known resource area, but the extent of anomalous copper and gold grades has not been completely delineated down dip or in the southwest direction.

Late, discontinuous veins, breccias, shear fillings, and patchy replacements similar to those in the Upper Panel occur throughout the Lower Panel fault block. A higher density of these late mineralized structures is reflected in average arsenic, lead, antimony and zinc concentrations being roughly two to three times those of the Upper Panel. Scattered, sub-meter to centimeter scale quartz and sulphide veins, breccia veins, shear fillings, patchy discontinuous clots or replacements and disseminations occur in all rock types except late dykes, but are most abundant in brecciated and crackled zones. They include coarse pyrite, carbonate, chlorite, quartz, occasionally with minor chalcopyrite, sphalerite, arsenopyrite or galena, and traces of tennantite. Native gold is rare but has been observed as sub-millimeter blebs and stringers in quartz-carbonate-sulphide veins, and chlorite-pyrite-carbonate breccia matrix fillings. A small number of very thin, volumetrically insignificant post-mineral dykes with meterscale widths cut all other lithologies at Sulphurets. These include northwesterly-dipping, fine-grained diabase dykes with aphanitic chilled margins and pervasive chlorite alteration, and two fine-grained, unaltered, black lamprophyre dykes dipping westnorthwest. Similar post-mineral dyke sets are observed in the Kerr, Mitchell, and Iron Cap zones.

Mitchell Zone
The Mitchell Zone crops out in Mitchell Valley, through an erosional window exposing the footwall of the MTF. The zone is a roughly cylindrical gold-copper-molybdenum deposit, dipping ~60° to the northwest, with approximate true dimensions of 1,600 m in strike, 1,500 m down dip, and up to 850 m in thickness. It remains open down dip and along strike to the northeast at depth. Recent glacial melt back has provided exceptional surface exposure of a gold-coppermolybdenum porphyry system. A zone of intense quartz and sulphide veining (“Sheeted Quartz Vein Zone”) forms resistant bluffs in Mitchell Valley. However, the higher-grade core area is mostly covered by talus and moraine west of the bluffs. Active oxidation and leaching of sulphides has produced prominent gossans and extensive copper sulphate precipitates at the surface.

The Mitchell deposit features many characteristics typical of gold-enriched calc-alkaline porphyry copper deposits: calc-alkaline syn-mineral intrusions; hydrothermal alteration assemblages that include deep potassic, peripheral propylitic, and extensive shallow sericitic alteration; and abundant quartz veining. Metals, chiefly gold and copper (in terms of economic value), are generally at low concentrations, finely disseminated, stockwork or sheeted veinlet controlled, and pervasively dispersed over dimensions of hundreds of metres. Grades diminish slowly over large distances; sub-economic grades are encountered at distances of several hundreds of metres beyond the interpreted centre of the system. This is distinct from the Sulphurets and Kerr zones, where there are more abrupt breaks in grade due to higher structural complexity and juxtaposition of weak and moderate grade domains by faulting, both syn-mineral structures controlling breccia contacts, and post-mineral faulting and displacements.

Iron Cap Zone
The Iron Cap deposit is the northernmost porphyry gold-copper-molybdenum deposit in the KSM district, and occurs structurally above the Mitchell deposit, in the panel of rocks between the MTF and STF. It is now known to be hosted by an Early Jurassic intrusive complex that is roughly contemporaneous with those in the Mitchell and Kerr zones. The Iron Cap mineralized zone forms a tabular body striking roughly north-south and dipping ~60° to the west, with approximate true dimensions of 1,500 m in strike, 1,500 m down dip, and up to 800 m in thickness. Mineralization remains open down dip.

Only the southern and eastern margins of the Iron Cap deposit outcrop at surface, where weak to moderate gold + copper ± molybdenum mineralization is primarily hosted in sedimentary strata of the Hazelton Group. It is now known that Iron Cap glacier covers the central and northern portions of the deposit, and that the western side of the deposit is concealed beneath the largely barren hanging wall of the STF.

Total quartz vein abundances at Iron Cap typically range from <1 vol.% to ~5 vol.%. However, a handful of discrete, narrow zones at Iron Cap feature notably high (>10 vol.%) abundances of sheeted A-veins, which correspond to zones of particularly elevated gold and copper grades.

The 2016 PFS uses conventional large-scale open pit and block cave underground mining methods. Pit phases at the Mitchell, Kerr, and Sulphurets deposits have been engineered based on the results of economic pit limit analysis. Starter pits have been selected in higher-grade areas. Underground mining has been proposed for the Iron Cap deposit and below the Mitchell open pit to limit the volume of waste generated from the potential open pits.

Ore is mined from Mitchell open pit from Years 1 to 24. Mitchell transitions to block cave mining as the Mitchell pit is mined out. Ore is mined from Sulphurets open pit from Years 1 to 17. Kerr open pit supplements block cave mining from Year 25 to Year 34, and during these years, ore will be transported by an overland conveyor and rope conveyor system starting at the Kerr pit. Mitchell block cave is estimated to have a production ramp-up period of six years, steady state production at 20 Mt/a for 17 years, and then ramp-down production for another 7 years. Iron Cap is estimated to have a production ramp-up period of four years, steady state production at 15 Mt/a for 10 years, and then ramp-down production for another 9 years. The underground pre-production period would be six years, with first underground ore production from Mitchell and Iron Cap in Years 23 and 32, respectively.

KSM open pit mining operations will employ bulk mining methods and large capacity equipment. Services and support are well established in BC and in the local area for this kind of operation.

The summarized production schedule including both open pit and underground mining. The mine production plan starts in lower capital cost open pit areas using conventional large-scale equipment before transitioning into block cave underground bulk mining later in the mine life. Starting pits have been selected in higher grade lower strip ratio areas and cut-off grade strategy is used to enhance revenues for a minimum capital payback period. The cut-off strategy stockpiles lower grade open pit material early in the mine life. The Mitchell and Iron Cap underground block caves are brought into a development and production sequence to provide continuous mill feed during the LOM, while evening out the mine’s sustaining capital requirements. The open pit sequencing is then adjusted to augment the underground ore production to meet the full mill throughput requirements. The Mitchell underground block cave starts ore production in Year 23 and ramps up to full production by Year 29. Iron Cap block cave ore production starts in Year 32 and reaches full production by Year 36. At this point onward, all ore is supplied by the Mitchell and Iron Cap underground block caves (a total of 96,000 t/d). As the Mitchell block cave production starts to ramp down (starting in Year 46), the mill feed is further reduced to 62,000 t/d. In the final years of production (Year 49 and onwards), the underground ore is supplemented with material stockpiled from the open pits to maintain 62,000 t/d of mill feed.

PRIMARY CRUSHING
There will be five primary crushing sites throughout the plant operation life at the Mitchell, Kerr, and Sulphurets sites, as well as in the underground block caving mines.

At the Mitchell OPC site, primary crushing will mainly consist of two 60 inch by 89 inch gyratory crushers, two apron feeders, and one train load surge bin feed conveyor. The ROM material feeding to the gyratory crushers will be from the Mitchell pit and the first year Sulphurets pit, and will be approximately 80% passing 1,200 mm. The oversize materials will be fragmented by a rock breaker. The gyratory crushers will reduce the ROM material to a particle size of 80% passing 150 mm or less. The products from each gyratory crusher will be fed to one 1.83 m wide by 37 m long conveyor via one 2.13 m wide by 10 m long apron feeder. The crushed ore from the two conveyors will be fed to a 2.13 m wide by 450 m long train load surge bin feed conveyor, which will be located inside of the Mitchell surge bin feed conveyor tunnel. The surge bin is designed to have a live capacity of 30,000 t (two pockets, each 15,000 t). The ore from the Mitchell open pit will feed to the mill during Years 1 to 22, 34, 35, 48, and 49.

For the underground block cave operation, the ore from the lower Mitchell zone will be mined by block caving and crushed on site to 80% passing 150 mm or finer. The crushed ore will be conveyed to the 30,000-t surge bin where the crushed ore will be blended with the materials from the Mitchell and Sulphurets pits and then loaded from the surge bin into the train cars and transported to the end of the MTT at the Treaty site. The ore will be fed to the mill during Years 19 to 49.

The Sulphurets ore will supplement the mill feed from Years 1 to 17, excluding Years 4, 5, 12 and 13, and with the ores from the other deposits during the last four years. The ROM ore from the Sulphurets pit will be trucked to the Mitchell site and crushed at the Mitchell crushing facility in Year 1. Starting from Year 2, the ore produced will be crushed by a 60 inch by 89 inch gyratory crusher at the Sulphurets mine site. The crushed ore will be conveyed to the Mitchell site via the 3.0 km SMCT to a 10,000-t Sulphurets/Kerr coarse ore stockpile. The stockpiled ore will then be reclaimed and trucked to the Mitchell crusher dumping pockets, where the ore will pass through the crushers and be sent to the 30,000-t surge bin together with the crushed Mitchell ore.

The ore from the Kerr deposit, together with the ores from the other deposits, will be introduced to the plant during Years 24 to 34 and 53, the ROM ore and waste rock from the Kerr pit will be crushed by two 60 inch by 89 inch gyratory crushers at the Kerr mine site. The crushed ore will then be conveyed to Mitchell through a 2,480 m cross valley rope conveyor to the Sulphurets site, followed by the 3.0 km overland conveyor through the SMCT to the Sulphurets/Kerr coarse ore stockpile at the Mitchell site. The ore from the stockpile will be trucked to the Mitchell crushing facility or to the 10-Mt surge stockpile for later reclaiming and delivery to the Mitchell crushing facility. Similarly, the reclaimed ore will be trucked to the Mitchell crusher dumping pockets, where the ore will pass through the crushers and be sent to the 30,000-t surge bin together with the crushed Mitchell ore.

The Iron Cap ore will be mined by block caving and crushed on site to 80% passing 150 mm or finer. The crushed ore will be conveyed to a surge bin located at the end of the Iron Cap and MTT connection tunnel. The ore will supplement the mill feed from Year 32 to the end of mine life.

SECONDARY CRUSHING
The reclaimed coarse ore will be conveyed to the secondary crushing facility and fed to four vibrating screens. Each screen oversize will feed a secondary cone crusher. Each secondary crusher is in closed circuit with a screen. The cone crusher product will return to the screen feed conveyor. A spare cone crusher is provided in the circuit for when any of the other four cone crushers require maintenance.

Screen undersize product that is finer than 50 mm will be delivered by conveying to an enclosed surge stockpile with a 60,000 t live capacity. The circuit will consist of the following key equipment:
• five cone crushers, each with an approximately 2.4 m diameter mantle and driven by a 750-kW motor or equivalent
• five 3.7 m wide by 7.3 m long double deck vibrating screens (one unit on standby).

TERTIARY CRUSHING
The reclaimed ore will be further crushed by four HPGR crushers. Four belt feeders will withdraw the reclaimed ore from the two HPGR feed surge bins and feed each of the four HPGR crushers separately. Each HPGR crusher is in a closed circuit with a 4.0 m wide by 8.0 m long double deck vibrating screen. Discharge from the HPGR crushers will be wetscreened at a cut size of 6 mm. The screen oversize will return to the feed conveyor of the HPGR feed bin while the screen undersize will leave the crushing circuit and report to the ball mill grinding circuits. The four HPGR crushing lines will have a total process capacity of 5,762 t/h. The key equipment is as follows:
• four HPGR crushers, each equipped with two 2,900 kW motors
• four 4.0 m wide by 8.0 m long vibrating screens
• four 1.5 m wide by 10.0 m long belt feeders.

PRIMARY GRINDING
The grinding circuit will employ conventional ball mills to grind the HPGR product to a particle size of 80% passing 125 to 150 µm. All the primary grinding circuits are designed to have a nominal processing rate of 5,762 t/h.

The primary grinding circuit will include four milling circuits, which are made up of the following equipment:
• four 7.6 m diameter by 11.9 m long (25 ft by 39 ft) ball mills, each mill driven by two 7.0 MW synchronous motors
• six 700 mm by 650 mm centrifugal slurry pumps (4 in operation and 2 on standby), each equipped with a 1,650 kW variable speed drive
• four hydrocyclone clusters, each with twelve 710 mm diameter hydrocyclones.

Each ball mill will be in a closed circuit with a cluster of twelve 710 mm diameter hydrocyclones. The hydrocyclone underflow will gravity-flow to the ball mill feed chute, while the overflow of each hydrocyclone cluster with a solid density of 37% weight/weight (w/w) will gravity-flow to one of the four copper-gold-molybdenum rougher flotation trains.

Lime will be added to each mill as required. Flotation collectors will be added to the
hydrocyclone feed sumps or to the hydrocyclone overflow collecting sumps.

COPPER-GOLD/MOLYBDENUM BULK CONCENTRATE REGRINDING
The copper-gold/molybdenum bulk concentrate will be reground to a particle size of 80% passing 20 µm in a regrind circuit consisting of three tower mills, each with an installed power of 2,240 kW, and a 250 mm diameter hydrocyclone cluster. The overflow of the hydrocyclones will gravity- flow to the bulk copper-gold/molybdenum cleaner circuit, while the underflow of the hydrocyclones will return to the regrinding mills by gravity flow.

GOLD-BEARING PYRITE CONCENTRATE REGRINDING
The pyrite concentrate will be reground to a particle size of 80% passing approximately 20 µm in three 2,240 kW tower mills. A hydrocyclone cluster consisting of twenty-six 250 mm diameter hydrocyclones will be incorporated with the mills in a closed circuit. The hydrocyclone overflow will report to the gold leach circuit or the copper-pyrite separation circuit.

Depending on copper content, the reground materials may be subjected to a flotation process to separate copper minerals from the other minerals. The copper concentrate will be sent to the copper-gold/molybdenum cleaner flotation circuit, while the flotation tailing will report to the gold leach circuit.

The proposed KSM plant for the 2016 PFS will have an average process rate of 130,000 t/d. A combination of conventional flotation and cyanidation processes are proposed for the PFS. The process plant will consist of three separate facilities:
• an ore primary crushing and handling facility at the mine site
• an ore transportation system by trains through the MTT
• a main process facility in the Treaty OPC area at the Plant Site, including secondary/tertiary crushing, primary grinding, flotation, regrinding, leaching/recovery, and concentrate dewatering.

The products from the primary grinding circuits will be fed into copper-gold/molybdenum rougher/scavenger flotation circuits, consisting of two operation circuits in parallel. The copper rougher flotation concentrates from the flotation circuits will be reground to a particle size of 80% passing, approximately 20 µm in the tower mills.

The reground rougher concentrate will then be upgraded in a clea ........