Four main styles of base metal mineralization have been identified on the Property:
• Hydrothermal Quartz Veins (MQV)
• Stockwork (STK)
• Stratabound (SMS)
• Mississippi Valley type (MVT)

The Hydrothermal Quartz Veins of the MQV (and STK), are characteristic of polymetallic base metal veins.

Quartz veins containing base metal mineralization occur in a north-trending, 16 km long corridor in the southern portion of the Property, where the occurrences are exposed on surface. Vein showings were referred to historically as Zones 1 through 12. The Main Zone, which includes the Main Quartz Vein (MQV) and other styles of mineralization, is found in historical Zones 1, 2 and 3. Vein Zones 4 to 12 extend discontinuously for about 10 km to the south of the Main Zone. The Rico showing is located approximately 4 km north of the Main Zone.

Stockwork (STK) type mineralization is associated with the MQV and does not appear to represent a true stockwork but rather a series of tensional splays from the MQV. STK mineralization is exposed underground in the 880m L and has been intersected in drillholes.

Stratabound (SMS) mineralization is associated with several of the vein zones and occurs near the currentlyknown lower limits of vein mineralization. Vein mineralization contains fragments of SMS indicating that the deposition of SMS pre-dated vein formation. SMS mineralization is not exposed on surface or underground and is known only from drillholes.

Mississippi Valley type (MVT) showings in the northern section of the Property are developed over a distance of approximately 10 km and from north to south are referred to as the Samantha, Joe, Horse, Zulu, Zebra and Road.

The Prairie Creek Mine will be a 100% underground mining operation extracting the majority of ore from a steeply-dipping, narrow, base metal bearing vein-fault structure referred to as the Main Quartz Vein (MQV). Three levels of underground adits (970L, 930L, 883L) were established previously at the Mine. Several shrinkage stopes were partly mined above the 930 and 883 levels, generating a stockpile of approximately 10,000 tonnes of mixed ore and waste that is stored near the mill.

Mining will be by longhole open stoping (LHOS) in the MQV vein and in the Stockwork (STK) area. Drift and fill (DAF) will be employed in the Stratabound Massive Sulphide (SMS) area. An average mining rate of 1,600 tonnes per day of ore is projected. At steady-state, approximately 585,000 tonnes of ore per year will be mined. Mine life is projected to be 14.5 years.

Mining of the MQV will be by LHOS. The mining level in the ore at the 883 m elevation has previously been established along a significant part of its length but will be slashed to 4.5 m W x 4.5 m H to serve as a mucking horizon. The average vein width is less than 4.5 m; where it exceeds 4.5 m, the level and sub-level widths will be adjusted appropriately. Mining below the 883 level will require similar main levels, driven 4.5 m W x 4.5 m H, to be established every 60 m vertically; within this 60 m height there will be a sub-level driven every 15 m or 20 m at 4.0 m x 4.0 m dimensions. Generally, a 15 m sub-level interval is adopted where the vein width is less than 3 m. Access to the sublevels will be gained by ramp and cross cuts. Ore development in the vein will be for a distance of up to 250 m north and south (each side) of the access point. Slots will then be developed between sub-levels followed by retreat LHOS towards the access in approximately 30 m panels. The lowest elevation sub-level will lead the mining front, with all ore being mucked from the main (mucking) level. Broken ore will be drawn down in a controlled fashion so as to provide interim wall support and assist in minimizing wall dilution. Fill fences will be constructed on all levels other than the uppermost, after the extraction of each panel. The mining cycle will thus involve ore development, followed by drilling, blasting, mucking, and filling.

The STK area, and any MQV areas where geometry necessitates less than 60 m high extraction, will generally be mined in similar longhole retreat fashion at individual panel heights up to 20 m. For STK mining, some access development through paste fill is projected for the later stages in the mine life.

The SMS zone is approximately tabular in nature, dipping at about 15 to 20 degrees and with thickness up to, nominally, 20 m. It will be mined using a primary-secondary DAF mining method. Panels will be driven at 5 m H x 7.5 m W to the extremities of the ore before filling with, largely, paste fill. Primary panels will thus generally have ore on either side, while secondary panels will generally have backfill on either side. Binder concentration in secondaries will generally be significantly lower than that for primaries. Extraction of each 5-m cut on any horizon will be followed by extraction of the cut above in similar fashion. Each access into the zone may be used for up to three cuts by taking down backs in the access after each cut is complete.

Metallurgical tests indicate that the Prairie Creek mineralization is amenable to a combined process of pre-concentration by dense media separation (DMS) and sequential flotation circuits for lead sulphide, zinc sulphide, and lead oxide concentrates.

The current crushing facilities have a 1,750 tpd capacity, with an installed jaw crusher, short-head cone crusher, double-decked screen, and conveyor systems feeding an 1,800 t fine ore bin. A new dense media separation (DMS) plant, with a nominal feed rate of 1,600 tpd, will be installed downstream of the crushing circuit and is expected to reject an average of approximately 25% of the feed as waste with minimal metal losses. The milling circuit is designed for 1,200 tpd at nominally 80% passing 156 µm. The ROM ore is expected to be softer initially and then harder as the mine develops deeper and an increase in the Bond Work Index is anticipated. As such, a new secondary ball mill (200 kW tyre mill) is planned for installation, costed as sustaining capital after 5 years of operation. Precise timing of this additional milling power will need to be optimized based on the work index progression over time and other economic factors.

The existing refurbished crushing circuits, consisting of a primary crushing unit and a secondary crushing unit in closed circuit with a vibrating screen, will reduce ROM ore to a particle size of 80% passing 10 mm.

The major equipment and facilities in this area include:
• ROM ore dump pocket (40 t live capacity) with a fixed grizzly and a vibrating feeder.
• Coarse ore surge bin (136 t) with an apron feeder fitted with grizzly bars.
• Kue-Ken 36'' x 24'' jaw crusher.
• Secondary crushing feed surge bin (45 t) with a belt feeder.
• Double deck screen with apertures of 25 mm and 15 mm.
• Symons Nordberg 5.5' shorthead cone crusher.
• Conveyors including a metal detector and a magnetic separator.
• Fine ore bin (1,800 t) with a reversible belt feeder.
• Dust collection systems.

The feed tonnage will be controlled by adjusting the speed of the fine ore bin discharge conveyor belt. Operators will have the ability to set an optimal feed rate based on DMS plant on-stream analyser information.

The DMS plant (new equipment) is designed to reject gangue material to reduce effective feed tonnage and increase feed grades to the downstream grinding and flotation circuits. The crushed ore is deslimed, whereby material finer than 1.4 mm is removed and is followed by a dense media (ferrosilicon) cyclone separation at a proposed separation SG of 2.8. The rejects from the DMS plant will be conveyed to a temporary 200 t stockpile (uncovered) and will be loaded onto the waste ore haul trucks by a front-end loader for transport to the waste rock storage facility.

The sink fraction will be discharged into the deslime pump box where the fines and sink will both be pumped to the primary ball mill grinding circuit. The DMS circuit is designed to be by-passed, whereby the feed will be directed to the grind circuit via the feeder under the fine ore bin.

The grinding circuit will consist of a ball mill in closed circuit with classifying hydrocyclones located within the existing mill building.

Polymetallic, sequential flotation will be employed to separate lead and zinc sulphide and lead oxide. Three separate flotation circuits will be installed in order: sulphide lead, sulphide zinc, and oxide lead flotation. All existing refurbished flotation cells will be utilized for sulphide flotation. The existing regrind ball mill will be refurbished and utilized to further grind the lead sulphide rougher flotation concentrate in order to maximize grade of the final lead sulphide concentrate.

Lead sulphide flotation:

The lead sulphide flotation circuit consists of rougher and three stages of cleaner flotation and the major equipment for lead sulphide flotation circuit includes:
• One new rougher conditioning tank, equipped with a mechanical agitator.
• Refurbished existing rougher flotation trough cells (ten (10) of 2.8 m3 capacity) with the existing concentrate diverter plates.
• New rougher flotation trough cells (seven (7) of 5 m3).
• Two rows of new 4 x 5 m3 1st cleaner, 1st cleaner scavenger, and 2nd cleaner flotation trough cells.
• Refurbished existing 3rd cleaner trough flotation cells (six (6) of 1.4 m3 capacity).
• Two (2) existing refurbished cleaner conditioning tanks, equipped with mechanical agitators.
• Ancillary equipment including pump boxes, sump pumps, and samplers.
• Refurbished existing regrind ball mill with cyclones, pumpbox, and pumps.

Zinc sulphide flotation:

The zinc sulphide flotation circuit consists of rougher flotation followed by three stages of cleaner flotation.

The major equipment for the zinc sulphide flotation circuit includes:
• Two (2) existing rougher conditioning tanks, each equipped with mechanical agitators.
• Refurbished existing trough rougher flotation cells (ten (10) of 2.8 m3 capacity).
• Refurbished existing trough 1st, 2nd, 3rd cleaner flotation cells and 1st scavenger cleaner flotation cells (twelve (12) of 1.4 m3).
• Ancillary equipment including pump boxes, pumps, and samplers.

Lead oxide flotation:

The lead oxide flotation circuit consists of new equipment including rougher / scavenger flotation and two stages of cleaner flotation cells located within a new building connected to the mill building via an arctic corridor. The lead oxide flotation circuit design is based on historical testwork (pre 2017) results. New lead oxide flotation floatation test work is underway and the new lead oxide flotation circuit will be optimized when the test results are available.

The major equipment proposed for the lead oxide flotation includes:
• Two (2) new rougher conditioning tanks equipped with mechanical agitators.
• Nine (9) 5 m3 new rougher / scavenger trough flotation cells.
• Five (5) 5 m3 new 1st and 2nd cleaner trough flotation cells.
• New building.
• Glycol heating system.
• Ancillary equipment including pump boxes, pumps, and samplers.

The concentrate from the three flotation circuits will be dewatered by thickening and pressure filtration. The lead oxide and lead sulphide concentrates are combined in the lead thickener, resulting in a blended lead concentrate. The filtered lead and zinc concentrates will be stored separately on site in a temporary stockpile before being loaded into 20 t purpose built concentrate containers. Both the existing concentrate thickeners and pressure filters will be refurbished and upgraded for use.