The Copperwood Project consists of sediment- hosted stratiform copper deposits. Such deposits consist of copper and copper-iron sulfide minerals hosted by siliciclastic rocks in which a relatively thin (typically less than 3 m thick) copper-bearing zone is mostly conformable with stratification of the host sedimentary rocks. Copper occurs as disseminations and veins.

Mineralization
Mineralization is hosted within two sedimentary sequences termed the Lower Copper Bearing Sequence (“LCBS”) and Upper Copper Bearing Sequence (“UCBS”) at the base of the Nonesuch Formation.

The LCBS is composed of the Domino, Red Massive and the Gray Laminated units.

The UCBS is composed of the Upper Transition, Thinly, Brown Massive and Upper Zone of Values units.

The Domino is the main mineralized subunit, averaging 1.6 m in thickness, but thinning to about 0.5 m on the eastern edge of the Copperwood Deposit. Copper assays at Copperwood are remarkably consistent within individual units with mean copper grades of 2.58 wt.%, 0.39 wt.%, and 1.32 wt.% for the Domino, Red Massive and Gray Laminated subunits, respectively. The Red Laminated demonstrates a localized 1% increase in copper grades occurring at the base of the unit adjacent to the Gray Laminated. Silver is also present, with mean grades of 5.5 g/t.

Chalcocite is the only observed copper sulfide- bearing mineral at Copperwood, occurring principally as disseminations within shale and siltstone. Individual disseminated grains of chalcocite are most commonly very fine-grained, approximately 5 to 50 microns (“µ:) in diameter. Chalcocite occurs as free grains and as complex grains where it appears to have replaced pyrite grains, as evidenced by remnant patchy domains of an iron oxide mineral (probably hematite). In the highest-grade samples, located in the top 0.3 m of Domino subunit, chalcocite occurs as layers that are parallel to laminations in the rock. These layers are usually less than 2 mm thick. Occasionally, ovoids of chalcocite occur that are up to 3 mm in their long axis. They possibly result from the replacement of organic carbon.

There is an overall negative correlation with the degree of oxidation of the host rock within the LCBS and the abundance of chalcocite within the LCBS. The dark-gray to gray colored Domino subunit has the highest copper grades; the medium to light-gray-colored Gray Laminated has medium copper grades; and, the redbrown colored Red Massive has distinctly the lowest copper grades.

Grade profiles for each of the LCBS units show that there is a natural break in the grade profile, at approximately 1 wt.% copper. The 1 wt.% copper grade is a natural cut-off and is extensively used in Zambian and other African sediment-hosted copper deposits, where most intercepts grade a few tenths of a percent copper above or below the mineralized interval and well over 1 wt.% copper inside the mineralized interval.

The UCBS hosts the same style of chalcocite mineralization as the LCBS, but contains trace to no chalcocite mineralization the western, thicker part of the Deposit. The copper grade gradually increases towards the center of the Western Syncline and Section 6 contains an UCBS grade of 0.5 to 0.8 wt.% copper. The UCBS becomes more mineralized in Section 5 and has a copper grade greater than 1.0 wt.% in the eastern half of the section where the thickness of the UCBS ranges from 2.5 to 3.2 m. Here the copper grades are greater than 1.5 wt.%, 3.0 wt.%, 0.3 wt.%, and 0.9 wt.% for the Upper Transition, Thinly, Brown Massive, and Upper Zone of Values subunits, respectively. The Upper Transition and Thinly units are of economic interest and were the focus of the resource estimate.

The proposed mining method for the Copperwood Project is conventional drill and blast room- and-pillar given the relatively sub-horizontal orebody that varies in thickness from 1.6 m to 3.7 m.

The method consists of the extraction of a series of entries and cross-cuts in the ore leaving pillars in place to support the back. The entries cross cuts and pillars are sized using a geotechnical analysis of the rock, and experience from other mines sharing similar ground conditions.

The Project’s mining equipment consists of a low-profile two-boom electric-hydraulic jumbo for drilling. A one-boom electric-hydraulic low-profile bolter is considered for the installation of ground support. A load haul dump (“LHD”) unit with a 10 t (6 yd3 ) capacity is planned for ore removal from the face and transport of the broken ore to a rock breaker- loading point. A rock breaker will reduce the size of larger particles in the blasted ore, which will be placed on a belt conveyor and transported to the surface crushed ore storage bins from which the mill is fed.

Main accesses and haulage of ore from certain distant working areas are developed using 30 t underground mining trucks to transport the ore to the rock breaker or to the surface stockpile. A mix of ANFO and emulsion explosives are used for blasting to reduce the excavation overbreak. The rooms are mined with a single pass approach, such that the pillars will immediately have their final dimensions. This approach is recommended for better control and better productivity.

The mine is comprised of two sectors; the Eastern part and the Western part. The Western part contains higher grades and a thicker mineralized zone. For these reasons, mining will begin in the western part. The mining direction will generally follow the dip of the orebody, but in some areas the dip is too steep to follow. In the areas where the dip is too steep, the mining will be done at an angle to the dip direction.

Based on geotechnical information and mineralization geometry, an underground room- and-pillar method is selected for the Copperwood deposit. This mining method allows for both a good ore selectivity and productivity. However, a series of pillars are left in place to provide roof stability. The mining design was based on a mining rate of approximatively 2.4 Mt/yr. The underground access and infrastructure development were designed to support the mining method and size based on mining equipment and production rate requirements.

Mining Parameters.
The basic operational assumptions are summarized as follows:
• Minimum mining height 2.1 m (limited by the equipment);
• Maximum mining height 5.8 m;
• Average mining height 2.5 m;
• Average mining height western sector 2.81 m;
• Average mining height eastern sector 2.21 m;
• Cut-off grade 1% Cu;
• Annual production – 2.4 Mt;
• Entry drift (main access) and room and pillar width 6.1 m;
• Lake Superior horizontal protection 30 m;
• Surface pillar 25 m;
• Old test mine pillar 10m;
• Fresh air raise 5 m;
• East exhaust air raise 5 m;
• West exhaust air raise 4 m;
• Conveyor maximum optimal distance to the face heading 250 m;
• Minimum of 12 rooms per operating panel.

The process plant design for the Copperwood Project is based on a metallurgical flowsheet designed to produce copper concentrate. The flowsheet is based on well proven unit operations in the industry.

The process plant has been designed for a throughput of 6,600 mtpd (dry). The overall flowsheet includes the following steps:
- Crushed ore reclaim;
- Grinding and classification;
- Rougher flotation;
- Rougher concentrate regrind;
- Cleaner flotation, using three stages of cleaning;
-Concentrate thickening and filtration;
-Tailings disposal.

Crushed Ore Reclaim.
Crushed ore from the underground mine will be conveyed to a crushed ore transfer conveyor equipped with a weightometer. This conveyor will discharge onto a bidirectional/reversible conveyor which in turn feeds the crushed ore bins. The two crushed ore bins will be equipped with two pan feeders, each to reclaim material to feed the SAG mill feed conveyor. The conveyor will be equipped with a weightometer for measuring and controlling the SAG mill feed rate.

A surplus ore feeding system, comprised of a hopper and a feeder, will allow ore material to be fed to the crushed ore bin via a front-end loader from the ore stockpile if required.

Grinding and Classification Circuit.
The grinding circuit will receive ore at a nominal top size of 203 mm with an 80% passing size of 150 mm. The circuit will consist of a SAG mill in closed circuit with a screen and a ball mill in closed circuit with a cyclone cluster.

The SAG mill will be a 7.92 m diameter x 4.21 m EGL mill with a 5,500 kW motor. The SAG mill will operate with 12% to 15% ball charge. Ore will be fed to the SAG mill at a controlled rate, nominally 274 dry mtph, and water added to the feed chute to achieve the desired milling feed density. Flotation reagents including sodium hydrosulphide (NaSH), alkylaryl dithiophosphate (A-249) and sodium isobutyl Xanthate (SIBX), will also be added to the mill feed. Product from the SAG mill will discharge over a grate with the oversize reporting to the scats bunker where it will be periodically removed by the skid-steer loader. Grate undersize will be pumped to the SAG mill discharge screen. The screen will be a single- deck inclined screen with a width of 2.4 m and length of 3.7 m. The screen deck will have an aperture of 2.0 mm. The screen oversize will be recycled back to the SAG mill and the undersize will gravitate to the cyclone feed pump box where it will be further diluted to achieve the required cyclone feed density.

Two vertical spindle sump pumps will service the grinding and classification area. The concrete floor under the mill area will slope to the sumps to facilitate cleanup. Grinding media for the mills will be introduced by use of a dedicated kibble.

Rougher Flotation.
Cyclone overflow will gravitate to the trash screen, which will be a linear screen designed to remove foreign material prior to flotation. Trash will report to the trash bin which will be periodically removed for emptying. Screen undersize will gravitate to the rougher conditioner tank. A sampler will be installed on the screen underflow line to take a sample to the On-stream Analyzer (“OSA”) for metallurgical, process control and particle size measurement purposes.

Regrind.
Rougher concentrate and second cleaner tailings will report to the regrind cyclone feed pump box. The slurry will be pumped to the regrind cyclone cluster by the regrind cyclone feed pumps. The cyclone underflow will gravitate to the regrind mill where water and lime (if required) will be added to achieve the desired milling density and desired operating pH respectively. The regrind mill will be a vertical mill and grinding will be achieved via attrition and abrasion of the particles in contact with steel media.

Cleaner Flotation.
Cleaner flotation will consist of three stages of closed circuit cleaning.

The first cleaner flotation cells will consist of six 18 m3 trough cells in series. First cleaner concentrate will gravitate to the first cleaner concentrate, while the first cleaner tailings will gravitate to the first cleaner scavenger flotation cells.

The first cleaner scavenger flotation cells will consist of seven 18 m3 trough cells in series. Lime, A-249 and SIBX will be added to the first cleaner scavenger flotation feed box where they will mix with the first cleaner flotation tail. First cleaner scavenger concentrate will be collected in a pump box and will be pumped back to the rougher flotation circuit. First cleaner scavenger tailings will gravitate to a pump box from where the material is pumped to the flotation tailings pump box. A sampler will be installed on this stream to take a sample to the OSA for metallurgical and process control purposes.

The second cleaner flotation cells will consist of six 8 m3 trough cells in series. Lime and SIBX will be added to the second cleaner flotation feed box where they will mix with the first cleaner concentrate. Second cleaner concentrate will be collected in a pump box and will be pumped to the third cleaner flotation circuit. Second cleaner tailings will be collected in a pump box and will be pumped to the regrind cyclone feed pump box.

The third cleaner flotation cells will consist of six 2 m3 trough cells in series. Third cleaner concentrate will be collected in a pump box and will be pumped to the concentrate thickener. A sampler will be installed on the pump discharge line to take a sample to the OSA for metallurgical and process control purposes. Third cleaner tailings will gravitate to the first cleaner concentrate pump box.

Concentrate Thickening and Filtration.
Final concentrate at 15.1 mtph solid will be pumped to the 16 m diameter high rate concentrate thickener, along with filtrate return from the filtration area. Flocculant stock solution will be further diluted to 0.25% w/w with process water in an in-line mixer prior to addition to the concentrate thickener. Thickener overflow at a flow rate of 41.6 m3/h will gravitate to the process water tank for re-use.

Thickened concentrate will be pumped batch wise to the concentrate filter press using the one operating, and one standby, GIW LCC-H 150-500 filter feed pumps. The filter 1,500 mm x 1,500 mm x 40 mm will remove water from the concentrate to meet the target moisture of approximately 9% w/w using a series of pressing and air blowing steps. After the desired filtration time of approximately 12 minutes, the filter press will open and discharge concentrate directly to the floor of the concentrate shed. Following discharge of concentrate, the filter cloth will be washed prior to the next cycle using raw water and Grundfos CR32-9 pump. Some 9.9 m3/h filtrate from the concentrate filter will be returned to the concentrate thickener by gravity. Filter cloth wash will be drained into the filter area sump pump.

A front-end loader (“FEL”) will be used to remove the concentrate from beneath the filter press and transfer it to the adjacent 542 t concentrate storage areas. Concentrates will be loaded into the loadout hopper by the FEL when required. Concentrate from the load-out hopper will be transferred to the concentrate trucks via a 900 mm wide concentrate feeder and 750 mm wide truck loading conveyor. The truck loading conveyor will be equipped with a weightometer.

Tailings Handling.
Rougher and first cleaner scavenger tailings will be combined in a mixing box from where a final flotation sampler will take a sample to the OSA for metallurgical and process control purposes. The mixing box discharge will combine with a number of intermittent reagent sump pump streams in the flotation tails pump box. Flotation tailings will be pumped to the Tailings Dam Facility (“TDF”).