Deposit Geology
The Project area, comprising the Kudz Ze Kayah claim blocks within which the ABM deposit is located, encompasses units of the Grass Lakes group. The surface geology of the property was initially mapped by Cominco in 1996 at 1:20,000 scale (Schultz & Hall, 1997) and subsequently by BMC at 1:20,000 scale in 2017 (Baker et al., 2017).

The ABM deposit (comprising the ABM Zone and Krakatoa Zone) primarily comprises continuous, shallowdipping massive sulphide mineralization hosted within a thick felsic package of volcaniclastics and coherent sill/flow complex that locally make up the Kudz Ze Kayah formation.

Massive sulphide of the ABM Zone is hosted within a felsic rock package, whereas the Krakatoa Zone is predominantly hosted by a pre-mineralization mafic sill located within the felsic volcanic package. Mineralization at Krakatoa also occurs in the felsic hangingwall units stratigraphically overlying the mafic sill, in what is broadly interpreted to be the equivalent of the ABM mineralized position. Only scattered vein-style and disseminated mineralization occurs within the mafic sill lying stratigraphically below the ABM Zone.

The upper limits of the ABM and Krakatoa Zones are truncated near surface and overlain by glaciofluvial sediments. The massive sulphide mineralization at ABM occurs under approximately 2– 20 m of glaciofluvial overburden and is up to approximately 30 m in true thickness, whereas the Krakatoa Zone occurs under approximately 30 m of glaciofluvial overburden and is up to approximately 22 m in true thickness. The downdip margin of the ABM Zone appears to transition into a mixed and variably carbonaceous felsic volcanosedimentary package, whereas the Krakatoa Zone currently remains open at depth beyond the down-dip extent of the mafic sill.

A post-mineralization brittle fault zone (East Fault) offsets the ABM and Krakatoa zones, and angular clasts of sulphide are to be found within the fault zone breccias. The south-eastern margin of Krakatoa is cut by another late brittle fault zone of the same generation (Fault Creek Fault). There exists a marked difference in the stratigraphy east of the Fault Creek Fault, with recent drilling having identified a package to the east of the fault, dominated by felsic volcaniclastics and minor felsic intrusives, which transitions conformably up into the overlying Wind Lake formation. The marked change in volcanic stratigraphy across the Fault Creek Fault, despite little of no evidence of a significant offset of the Wind Lake formation basal contact, could potentially indicate the presence of a syngenetic fault structure along the south-eastern limit of the Krakatoa Zone. Recent attempts at a reconstruction of the ABM Zone and Krakatoa Zone into a single massive sulphide unit are also not consistent with the degree of movement along the East Fault that is observed at the Wind Lake formation basal contact. These features could indicate the presence of syngenetic fault structures either side of the Krakatoa Zone that was later the locus of late-stage brittle faulting. As such, the area east of the Krakatoa Zone remains a significant exploration target. A schematic geological cross-section through both the ABM and Krakatoa zones.

Mineralization

ABM Zone
Massive sulphide of the ABM Zone is up to 39 m true thickness, extending approximately 700 m along strike and approximately 500 m down dip. It dips to the north-northeast at approximately 35° near surface, transitioning to a dip of approximately 15° at around 200 m depth below the valley floor. The up-dip extent of the deposit is truncated by erosion and covered by approximately 2–20 m of glaciofluvial overburden.

Massive sulphide mineralization of the ABM Zone occurs as several stacked massive sulphide lenses to the west, transitioning to a single massive horizon at around 415,025 m E and extending to approximately 415,250 m E where it is then truncated by the post-mineralization East Fault. Stockwork and disseminated mineralization occurs equally both in the hanging wall and footwall to massive sulphide, and to a lesser degree between massive sulphide lenses.

Sulphide mineralization is dominated by pyrite, sphalerite, pyrrhotite (+ marcasite), galena and chalcopyrite, with minor arsenopyrite and a range of sulphosalts predominantly comprising tennantite-tetrahedrite and freibergite. Both the up-dip part of ABM Zone and most of Krakatoa Zone have elevated sulphosalt content relative to the remainder of the ABM deposit.

Krakatoa Zone
Krakatoa Zone mineralization, bound to the west by the East Fault and to the east by the Fault Creek Fault, is hosted within Kudz Ze Kayah formation that dips at 35° to the north-northeast. Although of lesser extent, the distribution of mineralization within the Krakatoa Zone is more spatially complex than the ABM Zone due to the stacked mineralized lens system. Massive sulphide mineralization occurs within three principal mineralized horizons:

1. The “Upper lens”, broadly interpreted as the stratigraphic equivalent to the ABM lens.
2. The “Main lens”, the major component of Krakatoa Zone in terms of sulphide mineralization with a true thickness up to 22 m.
3. A less pronounced and semi-continuous “Lower lens”.

Krakatoa Zone mineralization is broadly concordant with stratigraphic layering of the host rocks, extending over approximately 200 m of strike, at least 500 m down dip, and up dip to the base of glacial overburden of 20–30 m thickness.

Several pre- to syn-mineralization growth faults are thought to influence the massive sulphide bodies at Krakatoa in terms of offsets and changes in massive sulphide thickness. Both the large coherent mafic and aphanitic rhyolite bodies appear to have an influence on the spatial distribution of sulphide mineralization. As these bodies are themselves mineralized, it is likely that these coherent bodies acted as fluid aquacludes during mineral deposit formation.

Host rock types and alteration styles of Krakatoa Zone mineralization are for the most part similar to those encountered in the ABM Zone. The key difference is the degree of mineralization associated with the mafic sill, which below ABM Zone is only poorly mineralized. The Main lens comprises the bulk of mineralization at Krakatoa, with massive sulphide occurring both within the felsic volcanics immediately beneath the mafic sill, and within the mafic sill, after replacement of enclaves of felsic volcaniclastics and/or replacement of the mafic sill itself.

Pursuant to the mining plan contained in the Feasibility Study the majority of the ABM Deposit will be mined by open pit mining methods. It is expected that a single pit will be mined, with mining of the ABM Zone comprising four separate stages, and with the Krakatoa Zone mined in a single stage. A total of 14.0 Mt of ore and 138.4 Mt of waste will be mined by open pit mining methods, for an expected average LOM strip ratio of 9.9:1. The Stage One ABM Zone pit has an expected strip ratio of 6:1, in order to facilitate a rapid payback of pre-production capital.

Open Pit Mining
The open pit optimization evaluated several slope sets based on D&S recommendations, but primarily allowing for haul roads to be placed on the hanging wall or the foot wall of the main mineralization.

The Krakatoa pit will be mined as a single stage, as the pit is small and mined near the end of the project life. A portion of the waste material in the Krakatoa pit will be mined early to create a lay down and portal staging area for the planned underground operation. The remainder of the pit is planned to be mined toward the end of the project and concurrently with underground mining.

The ABM Zone dips to the northeast. The deposit, on the surface, is confined by the valley running approximately north to south, and the pit will mine both sides of the valley hills. The main ramp entrance was placed on the north side of the ABM pit, at the lowest point possible, to minimize the amount of pioneering road works leading to the Process Plant, stockpiles and other infrastructure.

As a consequence, the impact of the northnortheast fault was reduced by ensuring the pit wall steps behind the fault once the wall approached within 10 m of the fault. In addition, a 40 m wide geotechnical bench at 1,400 mRL was included in the design to reduce the OSA.

An 8 m-wide perimeter bench will be established where the pit design intersects the base of the overburden. The perimeter bench does not have a fixed elevation; rather, it follows the surface of the transition zone. The bench face angle through the overburden layer is related to its thickness as assessed by D&S.

The haul road designs are based on a fleet of 140 tonne haul trucks, for which 27 m-wide ramps are designed for a double-lane road, including a safety berm on the pit crest side and a drainage ditch on the pit wall side. Singlelane ramps were designed to be 20 m wide.

Underground Mining
The KZK Project comprises two mineralized zones, ABM and Krakatoa. Underground mining has only been considered for the Krakatoa Zone.

Insufficient mineralization has been defined, and complex geotechnical conditions exist below the current ABM pit design to justify underground mining in this area at present. The primary mining method planned is underhand longhole stoping with cemented paste-fill for footwall and hangingwall mining areas. Development of the underground mine is planned to commence in July 2026, once the ABM Stage 1 open pit has progressed to the 1,355 mRL bench and excavated the portal area. Underground operations are scheduled for completion in June 2031.

The planned sequence of mining will see the upper levels of the underground mine extracted and paste-filled, and the open pit mined down towards this paste pillar later in the Project. The following recommendations are provided from the Geotechnical report (Dempers & Seymour, 2019b):
- Stope voids, as well as any access development within 20 m of the final pit walls are to be tight filled with cemented paste-fill
- Any stope voids or development within 15 m of the pit floor are to be probed drilled from the pit and treated as voids during pit production
- A monitoring program for the pit walls will be required to monitor and assist the planning and implementation of any mitigation strategies, where large wall movements are detected, or the potential indicated by the monitoring.

Access to the underground mine will be via a single ramp with portal at the 1,355 mRL bench from the saddle area within stage 1 of the ABM open pit. Access to the underground portal area will become available in the first half 2025. Underground trucks will haul ore and waste out of the mine and dump adjacent to the portal, where the open pit load and haul fleet will rehandle the material to the ROM pad or waste storage facility as appropriate.

A second ramp is proposed for ventilation of the underground workings as there is a significant layer of overburden material overlying the competent bedrock. This makes raise boring or conventional raising difficult and uneconomic, given the likelihood that shaft sinking would be required through the overburden before commencing vertical development.

Crushing
A reinforced concrete steel bridge, with retaining wall, extends from the ROM pad to the ROM bin dump point. This bridge provides access for the FEL. A Caterpillar 988 FEL or equivalent will be used to feed the crusher from the ROM pad. A 900 mm grizzly for scalping oversize material is installed on the ROM Bin which will have 20 minutes retention time (135 t).

ROM ore is withdrawn from the bin by an apron feeder and fed to a vibrating grizzly for removal of fines. The vibrating grizzly will operate ahead of the primary crusher to remove fines from the crusher feed. The Design Case throughput rate for the crusher was estimated to be 446 t/h, operating 13.5 hours per day.

Provision was made for tramp metal magnet on the Primary Crusher Discharge Conveyor, as well as a metal detector on the Coarse Ore Stockpile Feed Conveyor.

Insertable bag type dust collectors are provided to collect and filter out fugitive dust emissions from the materials handling circuit.

Normal crusher feeding practice will entail the crusher operator manning the FEL and loading the ROM bin. Video monitors in the FEL cab will allow the operator to monitor the status of the crusher during loading operations. An emergency stop switch located in the FEL cab will be capable of shutting down all crushing operations remotely from the cab.

Grinding – SAG and Ball Mills
The SAG Mill and Ball Mill grinding circuit are located at the southern end of the Process Building where the ore is fed from the Coarse Ore Stockpile via the SAG Mill Feed Conveyor. The grinding circuit will comprise an open circuit SAG Mill and a Ball Mill in closed circuit with cyclones.

The SAG Mill will be a 5.79 m diameter x 5.49 m effective grinding length (EGL), grate discharge, steel-lined mill, driven by a 2.7 MW single pinion drive. The SAG Mill will discharge over a 12 mm aperture trommel screen. Trommel oversize (pebbles and steel scats) will be returned to the SAG Mill Feed Conveyor by three recycle conveyors in series.

The Ball Mill be a 4.72 m diameter x 7.32 m EGL, overflow discharge, rubber-lined mill driven by a 2.7 MW single pinion drive. The mill will be driven by a fixed speed drive and will operate at nominally 75% of critical speed. The Ball Mill will discharge over a 10 mm aperture trommel screen. The oversize will discharge into a bunker for disposal as waste. The undersize will gravitate into the mill discharge hopper.

The SAG Mill trommel screen undersize will also gravitate to the mill discharge hopper, where the combined mill discharge will be diluted with process water and pumped via duty/stand-by pumps to a hydrocyclone cluster for classification. The overflow from the cluster will flow by gravity to the flotation feed trash screen, to remove any trash prior to flotation. A portion of the cyclone underflow can be directed to the SAG Mill to facilitate balancing of the grinding in the SAG Mill and Ball Mill as the SAG Mill will generally have spare capacity on most ore types.

A common liner handler will be used to facilitate removal and installation of the SAG Mill and Ball Mill liners during planned mill relines.

An overhead gantry crane will be used for recharging grinding media as well as maintenance of the mills and cyclones.

Provision has been made within the Grinding and Classification area to receive a gold recovery facility if required in the future.

Regrind – Vertical Mills
Regrinding the copper, lead and zinc rougher concentrates to P80 of 30 µm, 30 µm and 35 µm respectively has been included based on testwork. A single Metso SMD 355 kW unit was selected for each of the copper, lead, and zinc regrind duties. The plant layout has allowed space for an additional regrind mill should future expansion be required.

The Kudz Ze Kayah Process Plant and associated facilities has been designed to process ROM ore at a rate of 2.0 Mtpa to produce separate copper, lead, and zinc concentrates and tailings; however, the plant will be capable of processing at 270 tph based on average ore comminution properties and average plant feed grades. The process rate will be varied depending on the grade of the ore.
The process flowsheet consists of following key stages:
• Crushing, stockpiling and grinding of the ore.
• Pre-float, rougher and cleaner flotation of copper, including regrind of copper rougher concentrate.
• Sequential pre-float, rougher and cleaner flotation of lead, including regrind of lead rougher concentrate.
• Sequential pre-float, rougher and cleaner flotation of zinc, including regrind of zinc rougher concentrate.
• Thickening, filtration, and stockpiling on site of copper, lead, and zinc flotation concentrates. Copper and zinc concentrates will be loaded in bulk o ........