Summary

Deposit type

• Porphyry
• Intrusion related

Summary:

New Afton is an alkalic coppergold porphyry deposit.

The New Afton deposit is located at the northwest end of the southern pluton of the Iron Mask batholith; it straddles the contact between the Pothook diorite and volcanic rocks of the Nicola Group. The deposit is bounded to the south by a picrite unit, itself intruded by dykes of the Sugarloaf diorite. Several post-mineral mafic and latite dykes crosscut the other intrusive and volcanic rocks. These dykes are irregular, discontinuous, and volumetrically limited, but appear to have some correlation with structural zones that controlled the emplacement of mineralization. Two suites of younger sedimentary rocks sit unconformably on top of the Nicola Group rocks and Iron Mask intrusive phases: the Ashcroft Formation to the south and the Kamloops Group to the north.

The New Afton mine area is crosscut by a series of arc-related regional-scale brittle-ductile shear zones of various orientations including northwest-, east-, and northeast-trending. Such shear zones are commonly developed along the margins of intrusive bodies; they are interpreted to control the emplacement of the Iron Mask Batholith and related hydrothermal alteration and mineralization. Later episodes of post-mineral extension reactivated these structures, leading to dextral brittle faulting along pre-existing northeast-trending shear zones and to normal movement along pre-existing northwest-trending shear zones.

The deposit consists of three principal zones. First, the Main zone, located on the western edge of the Pothook diorite is subdivided into Lift 1 East, Lift 1 West (both mined out), B3, C-Zone, and D-Zone mining zones (mining is currently focused on the B3 and C-Zone). Second, the HW zones are smaller satellite zones located along the southern margin of the Pothook diorite. Third, the Eastern zones include two separate areas located on the northern margin of the Pothook diorite: East Extension and K-Zone. East Extension is currently in the mine planning phase.

Mineralization is subdivided into three types: hypogene (either chalcopyrite- or bornite-dominant), secondary hypogene (sometimes referred to as mesogene) (overprint of tennantite-enargite + tetrahedrite and bornite + chalcocite rims), and supergene (native copper and chalcocite).

The alteration paragenesis comprises a complex sequence of potassic to calc-potassic and propylitic alteration, in turn overprinted by fault-controlled phyllic assemblages, followed by localized argillic alteration. Copper-gold mineralization is directly related to biotite-dominant potassic/calc-potassic alteration in the central core of the system. Alteration assemblages are categorized and modelled into six principal alteration domains: calcic, biotite-dominant potassic/calcpotassic, potassium (K)-feldspar-dominant potassic/calc-potassic, propylitic, phyllic, and argillic.

Mineralization
The New Afton deposit is a silica-saturated alkalic copper-gold porphyry deposit associated with magmatic phases of the Iron Mask Batholith. Copper-gold mineralization typically occurs as east-west subvertical tabular zones of disseminations, stringers, and fracture-filling sulphides within volcanic rocks of the Nicola Group and Pothook diorite. Host rocks have been altered and mineralized by multiple phases of monzonite intrusions and by dykes believed to be of Cherry Creek affinity. The monzonite intrusions and dykes are spatially associated with mineralization, although are not generally mineralized themselves whereas the monzodiorite dykes are often well mineralized. New Afton mineralized zones can be broadly categorized into three main areas: the Main Zone, Hangingwall (HW) zones, and Eastern zones:

• The Main Zone is a southwest-plunging tabular zone located on the western edge of the Pothook diorite; the zone extends for over 550 m along strike and over 1.5 km down-plunge. It begins on surface as the Afton Pit and continues underground subdivided into Lift 1 East, Lift 1 West, B3, C-Zone, and D-Zone mining zones. The B3 and C-Zone mining zones of the Main Zone are the only zones currently being mined.

• The HW zones are smaller satellite zones located along the southern margin of the Pothook diorite. They are roughly tabular and extend 325 m along strike and 800 m at depth.

• The Eastern zones include two separate areas located on the northern margin of the Pothook diorite: East Extension and K-Zone. East Extension is a tabular, southwest-plunging zone, that extends approximately 300 m along strike and 300 m at depth. K-Zone is currently being explored; its geometry is similar to that of East Extension, but its absolute dimensions are not known.

The mineralized zones at New Afton are grouped into three broad mineralization styles: hypogene, secondary hypogene (or mesogene), and supergene. Hypogene refers to primary sulphide mineralization which is characterized by the presence of chalcopyrite and bornite. Hypogene mineralization is defined for core logging purposes as containing more than 1% chalcopyrite or 0.5% bornite and is mainly associated with biotite alteration. Throughout the New Afton footprint, hypogene mineralization is subdivided in two distinctive styles:

• Chalcopyrite-dominant mineralization hosted in Nicola volcanic rocks along the margins of the monzonite stocks (Main Zone and HW zones).

• Bornite-dominant mineralization hosted in monzodiorite dykes, diorite, and volcanic rocks, located along the margins of the Pothook diorite. Monzodiorite is interpreted as causative intrusion phase for this style of mineralization (East Extension and K-Zone).

Secondary hypogene (sometimes called mesogene) mineralization is narrow, discontinuous, and commonly restricted to brittle faults. It is formed as a later overprint of tennantite-enargite + tetrahedrite, with bornite and chalcocite rimming primary sulphide mineralization.

Supergene mineralization consists of native copper and chalcocite that formed through oxidation of primary sulphides within the uppermost portions of the deposit that were exposed to weathering and erosion. It is defined for core logging purposes as containing 0.5% or more native copper, or, in the absence of native copper, intervals of strong oxidation (hematite and clay) with a threshold assay of 0.2% Cu. The supergene domain is roughly conical in shape and centered below the historical Afton pit.

Mining Methods

• Block caving
• Longhole stoping

Summary:

The New Afton underground mine consists of three zones, each at different stages of development:
• B3 is a fully operational block cave that has been in production since 2021.
• C-Zone is a block cave that transitioned from production ramp-up phase to commercial production in the fourth quarter of 2024.
• East Extension is planned as a long-hole stoping zone and is not yet in production.After completion of ore extraction, stopes are backfilled using a combination of rockfill and cemented rockfill (CRF).

The East Cave and West Cave, together referred to as Lift 1, were mined from 2011 to 2022 and are now depleted.

The New Afton Mineral Reserves are based on block caving and long-hole stoping underground mining methods.

Mine design and mining sequence
Underground access
The underground mine is accessed by decline from a portal on surface located to the south of the processing plant. From surface to a depth of 650 m below surface, a single 5.5 m wide × 6.0 m high decline is used for both vehicle access and the conveyor, which is suspended from the back of the decline. From this elevation to the bottom of CZone at 1,150 m below surface, the mine has two declines: a 5.5 m wide × 5.8 m high access decline and a 5.5 m wide × 6.0 m high conveyor decline.

An exploration ramp was developed from the New Afton pit to provide early access for Lift 1 development and construction but is no longer accessible since the East Cave breakthrough to surface. Emergency egress is available through a fresh-air raise equipped with an Alimak elevator and a staging area.

B3 block cave
The B3 block cave extraction level is approximately 160 m below the mined-out Lift 1 and 760 m below surface. The B3 footprint measures approximately 250 × 125 m for a footprint area of approximately 31,000 m2 ; this is smaller than the Lift 1 and C-Zone block cave footprints. B3 has a total of 65 drawbells.

The B3 extraction level is designed with four longitudinal strike drives and 111 drawpoints arranged in a straightthrough (El Teniente-style) pattern. Drawbell spacing is 16.5 × 27.0 m. Orepasses are located on the level’s east side.

The undercut level was designed 18 m above the extraction level (floor-to-floor) with five undercut strike drives. An apex level was developed in the expected critical hydraulic radius (the expected hydraulic radius required for the cave to self propagate, HRCR) to de-risk initial caving; it was successfully omitted from the remainder of the footprint to reduce development costs. A haulage level is located 20 m below the B3 extraction level where haul trucks are loaded from chutes at the bottom of the orepasses.

C-Zone block cave
The C-Zone extraction level is located approximately 390 m below the B3 extraction level and 1,150 m below surface. The footprint of C-Zone measures approximately 460 × 120 m for an area of approximately 55,000 m2 . C-Zone has a total of 91 drawbells, of which 26 have been blasted as of the end of 2024.

Development of the dual decline from B3 to C-Zone commenced in 2019 and reached the C-Zone footprint in the second quarter of 2022. Undercut blasting commenced in mid-2023 and the first C-Zone drawbell was blasted in October 2023. New Afton achieved commercial production at C-Zone in the fourth quarter of 2024.

In 2020, New Gold completed a redesign of the C-Zone footprint, resulting in improved stress management and increased operational flexibility. The C-Zone footprint includes a footwall access and conveyor decline; it is designed in five levels, listed from top to bottom:
• Undercut level.
• Extraction level.
• Haulage level.
• Ventilation level.
• Dewatering level.

Following the success of the reduced apex level at B3, the apex level is omitted from the C-Zone design, eliminating approximately 2,000 m of development originally planned in the Feasibility Study design.

The undercut level is 20 m above the extraction level; it includes 18 undercutting drives that are designed to sit directly above the 18 lines of the drawbells on the extraction level. The southern end of each undercut drive includes a wider section for the purpose of slot blasting. The undercut level features two orepasses connecting down to the haulage level and one temporary vent raise to the extraction level.

The extraction level has 7 transverse crosscuts, 91 drawbells, and a total of 177 drawpoints arranged in a herringbone layout with a drawbell spacing of 18.0 × 27.0 m. The north-south alignment of the strike drives allows for targeting of the ore contact on the south border of the cave, and provides increased flexibility and improved automation capability. The extraction level has four access drives that connect the extraction footwall drive to the main C-Zone footwall drive, itself located to the north of the footprint. The extraction footwall drive features seven orepasses and one vent raise that each connect to the haulage level below.

The haulage level is located north of the cave footprint and 25 m below the extraction level. The haulage level contains the gyratory crusher in the centre of the level, multiple large muck storage areas, battery bays on either side of the level, and a motor room access drive. The level has three accesses to the main C-Zone footwall drive as well as seven orepasses and two ventilation raises connecting to levels above and below.

East extension mining zone
East Extension is a new zone that was added to Mineral Reserves in 2024. Located 120 m east of the C-Zone block cave, and 150 m above the C-Zone extraction level, the East Extension Mineral Reserves extend approximately 200 m vertically and 140 m along strike. East Extension will be mined longitudinally using the long-hole open stoping mining method. The current design has ten levels, spaced at 20 m vertical intervals, with ramp access from the east. Each level has a single or second parallel ore drive running east-west, with dimensions of 5.0 m wide × 5.0 m high.

There are 114 stopes designed in three panels to optimize scoop productivity; the panels are separated by 5 m thick sill pillars. Based on geotechnical core data and stope stability analysis, stopes were designed with dimensions of 14 m long × 20 m high and a variable stope width up to 20 m. Stoping is sequenced bottom-up within each panel and retreats eastward to the ramp access on each level. After the ore is mucked out, stopes will be backfilled using a combination of rockfill and cemented rockfill (CRF).

Development of the East Extension ramp is scheduled to commence in the second half of 2025 and ore production is planned to take place concurrently with production from the C-Zone block cave from 2026 to 2031.

The underground mine has all the required mobile mining equipment to support current block cave production and C-Zone development. Mining activities are carried out by New Gold personnel and equipment, utilizing mining contractors where required, mostly to support C-Zone cave construction. The purchase of additional mining equipment is considered in the LOM plan to facilitate the C-Zone production ramp up and mining of the East Extension zone.

Comminution

Crushers and Mills

Summary:

Crushing
Run-of-mine ore is crushed to minus 150 mm.

The system consists of two FLSmidth 1100 × 1800 mm gyratory crushers, located on the Lift 1 and C-Zone haulage levels. The C-Zone crusher is located outside of the anticipated cave-induced abutment stress zone. Trucks and LHDs dump directly into the gyratory crushers; both crushers have two dump points to increase dumping efficiency and shorten cycle times. Each crusher is equipped with a remotely controlled rock breaker. Below the crushers are 800 t surge bins that feed crushed material onto the conveyor belt system. The two gyratory crushers can feed the conveyor system simultaneously by adjusting their respective apron feeder speeds at the bottom of the ore bins

A jaw crusher installed during Lift 1 mine development is available as a back-up crusher and has a capacity of 6,700 tpd. Additionally, an MMD GPHC Ltd. 625 mineral sizer was installed as a temporary crusher in the C-Zone conveyor decline to improve material handling efficiency during development and construction of C-Zone. The sizer will be moved to its permanent location, downstream of the gyratory crusher, in 2025 to provide secondary crushing; this will improve mill grinding efficiency and metal recovery at full production from C-Zone.

Grinding
Located beneath the crushed ore stockpile, two 1.8 m × 11 m apron feeders regulate the flow of ore onto the SAG mill feed conveyor. The SAG mill is an 8.5 m diameter × 4 m long Farnell-Thompson mill, driven by a 5,220 kW GE motor with a variable speed drive. The SAG mill discharge is screened over a 2.4 m × 6.1 m Deister double-deck screen with 8 mm × 34 mm apertures on the lower deck. The screen-deck was upgraded from single to double deck as part of the 2015 expansion to allow for an increased milling rate. Both the upper and lower deck oversize are recycled to the SAG mill-feed conveyor, with the option of crushing this recycle stream using an FLSmidth XL600 Raptor cone crusher.

Secondary grinding is accomplished using a 5.5 m diameter × 9.8 m long Farnell-Thompson fixed-speed ball mill driven by a 5,220 kW motor, in closed circuit with seven (five operating) Krebs GMax-26 hydrocyclones. Approximately 7% of the cyclone feed is diverted to a Gekko inline pressure jig and magnetic separation circuit for native copper and gold recovery and magnetite rejection, with concentrate reporting to the concentrate thickener. In addition to the feed diverted to the jig circuit, approximately 8% of the cyclone feed reports to an Outotec SkimAir 500 flash flotation cell with concentrate reporting to the regrind circuit, and the tails reporting to the ball mill feed. The cyclone overflow reports to the tertiary circuit.

Tertiary grinding is accomplished using a Metso Vertimill 3000 in closed circuit with seven (five or six operating) Krebs GMax-26 hydrocyclones. The tertiary cyclone overflow reports to the rougher flotation cells. Approximately 15% of the tertiary cyclone underflow reports to a continuous CVD42 Knelson concentrator for native copper and gold recovery with concentrate reporting to the cleaner inline pressure jig feed. Both the SAG and ball mill circuit control is supported with an expert control system.

Processing

• Gravity separation
• Inline Pressure Jig
• Centrifugal concentrator
• Crush & Screen plant
• Flotation
• Magnetic separation
• Dewatering
• Filter press

Summary:

The processing flowsheet at the New Afton Mine consists of conventional crushing and grinding circuits, a flotation circuit and gravity circuit. Run-of-mine ore is crushed at the underground gyratory crusher and transported via conveyor belts to the crushed ore stockpile on surface. Ore is reclaimed from the stockpile using two apron feeders and transported to the grinding circuit, consisting of a SAG mill and ball mill.

With processing of supergene ore being completed during the third quarter of 2022, the gravity circuit operation was adjusted to focus on recovery of gold rather than of native copper. The concentrates from the flotation and gravity circuits were combined to produce the final bulk copper-gold-silver concentrate for dewatering.

The processing plant throughput is currently limited by mine production and, with C-Zone ramping up in the next few years (2025-2026), the New Afton Mine intends to take advantage of the existing processing capacity at the mill to process up to 16,000 tpd.

Flotation
The tertiary grinding cyclone overflow flows by gravity into the rougher flotation circuit, which consists of two staged flotation reactor (SFR) cells in series followed by six 100 m3 flotation tank cells in series. The two SFRs were commissioned in Q2 2017. The concentrate from the rougher flotation cells is collected in launders and flows by gravity to the regrind circuit; the tailings from the final rougher cell is discharged into the tailings pumpbox. The regrind circuit grinds the flash and rougher flotation concentrates, decreasing the particle size to 80% passing 35 µm to 40 µm prior to processing in the cleaner flotation cells.

The regrind circuit consists of a 932 kW Vertimill in closed circuit with the regrind cyclopac. The regrind cyclopac consists of six (five operating) Krebs GMax-15 hydrocyclones. The underflow stream from two of the operating regrind cyclones is processed through two XD-40 Knelson concentrators to recover liberated gold and native copper from the regrind circuit. The Knelson concentrate discharges to the 3rd cleaner concentrate pumpbox, where it is pumped to the concentrate thickener. The Knelson concentrator tailings are discharged back to the regrind cyclone feed pumpbox. The regrind cyclone overflow discharges into the cleaner flotation circuit and the tailings flow to cleaner scavenger flotation. Cleaner scavenger tailings report to the tailings pumpbox. Three SFR cells were added to the head of cleaner flotation as part of the mill expansion project in 2015 to increase cleaner flotation capacity. The concentrate from these three cells is combined with the inline pressure jig final concentrate, 3rd cleaner concentrate, and regrind Knelson concentrates to produce the final bulk copper-gold-silver concentrate for dewatering.

Dewatering
The final concentrate is pumped to the concentrate thickener, where the solids achieve an underflow slurry density of approximately 55% solids. The slurry is pumped to an agitated tank and subsequently pumped into one of the two filter presses, where it is dewatered to approximately 8% moisture. The dewatered concentrate is discharged from the filter presses directly into the concentrate storage shed, before truck transportation to either the DP World Fraser Surrey Docks container port for ocean shipment to a smelter, or to the Ashcroft terminal for transportation by rail to a smelter in Quebec. In the case of DP World, concentrate is loaded into containers (two per truck) at the New Afton shed. These containers are stored at the port then emptied into the bulk hold of the ship. Empty containers are returned to site for reloading. In the case of Ashcroft, the concentrate is loaded into side-dump trucks at the New Afton shed then stored in stockpiles at the Ashcroft terminal before loading into railcars.

Thickened and amended tailings (TAT)
The rougher and cleaner scavenger flotation tailings are combined in the mill and pumped to the 45m Outotec paste thickener. The slurry discharges to the thickener feed tank. Flocculant is added at the feed tank and/or the thickener feedwell. The slurry exits the bottom of the feedwell into the thickener and is separated into two streams: supernatant thickener overflow and sedimented thickener underflow. The thickener underflow solids concentration is typically maintained in the 61–65 wt% solids range with an average of 63 wt% solids in 2024.

The thickener underflow is pumped out from the bottom of the thickener using a centrifugal pump. The pump discharges to a distribution header which splits the flow equally between the operating cement mixing and tailings pump trains. There are two operating pump trains and one on standby. Each pump train consists of a paste mixer, a pumpbox, a centrifugal charge pump and a high-pressure positive displacement pump. The positive displacement pumps discharge into a combined line, with the deposition location controlled at a valve yard close to the TAT facility. TAT can be discharged to the NATSF or at one of four spigot points along the APTSF (Afton Pit Tailings Storage Facility).

The thickener overflow exits at the top of the thickener via a weir into a collection launder. The launder discharges to a pipe which feeds the thickener overflow pumpbox. The water is returned to the mill process water system to maintain the mill operational water balance. Anti-scalant is added to control calcium carbonate buildup resulting from lime addition in the mill and the relatively high temperature of the recirculating process water.

Processing improvement projects
Two processing improvement projects are planned for 2025 with the objective of maintaining or improving metallurgical recoveries at the higher throughput rates as C-Zone ramps up to full production:
• Secondary crushing.
• Cleaner circuit upgrade.

Secondary crushing
An MMD 625 mineral sizer was installed as a temporary crusher in the C-Zone conveyor decline to improve material handling efficiency during development and construction of C-Zone. The sizer will be moved to its permanent location, downstream of the gyratory crusher, in 2025 to provide secondary crushing which will improve mill grinding efficiency, mill throughput stability and thus metal recovery at full production from C-Zone.

Cleaner circuit upgrade
In the second half of 2025, the existing 3rd cleaner flotation bank (4 × 5 m3 Outotec Tank Cells) will be replaced by a Glencore Jameson E1732/4 cell. The existing 2nd cleaner flotation bank (5 × 5 m3 Tank Cells) will be repurposed to operate as a recleaner-scavenger bank. The purpose of the upgrade is to increase overall copper and gold recoveries in C-Zone at a given final concentrate grade by improving the recovery of ultrafine particles in the cleaner circuit while maintaining cleaner recoveries at a higher rougher mass pull. The Jameson cell provides increased cleaning efficiency for a given footprint with lower energy consumption. The technology and flowsheet were selected based on a Hatch Ltd. study of alternative cleaner flotation technologies and on site pilot testing in 2023 and 2024.

Pipelines and Water Supply

Summary:

The New Afton processing facility uses one source of fresh water and multiple sources of reclaimed water. Water drawn from Kamloops Lake is used for applications requiring fresh rather than reclaimed water, as well as to make up any deficit in the site water balance. Water is reclaimed from the pond generated by consolidating tailings in the NATSF and transported via the PHTSF (Pothook Tailings Storage Facility) for use as mill process water. The dewatering system for the underground mine is also used as mill process water. The majority of mill process water is currently reclaimed from the tailings thickener overflow. Minor sources of process water include the HATSF (Historical Afton Tailings Storage Facility) wells and the dewatering system for the APTSF.

Fresh water is drawn from Kamloops Lake and is used primarily for ore processing make-up water, as road dust suppressant, for vehicle wash-down, fire control, and drilling. Water balance modelling is used to track the inventory of water on site, as well as water consumptions and water losses.

A water pipeline, approximately four kilometres in length, delivers fresh water from Kamloops Lake to the mine site.

Fresh water from Kamloops Lake is provided to the underground mine for both utility and fire water use. Underground water supply is via a 6” steel pipeline suspended from the back of the main conveyor declines and distributed throughout the mine. The crushers and conveyor systems and primary underground maintenance shops are outfitted with fire detection and sprinkler suppression systems.

Water from the NATSF is used at the mill for processing as water is currently ponded on the NATSF. However, after dewatering of the NATSF, reuse will be sourced from the APTSF drainage through the mine dewatering system and the water cap at the PHTSF will become the main water management pond. The expected date for the removal of the NATSF pond is the second half of 2025. At that time, any water required beyond on-site reuse will be pumped from Kamloops Lake, as per current licences.

Removal of the NATSF pond is being managed by utilizing process water over fresh water, which reduces the overall water volumes on site, and by using mechanical evaporators to accelerate natural evaporation processes. New Afton operates 12 mechanical evaporators from April until October but this will cease with removal of the pond in the second half of 2025.

Tailings seepage water is collected either in the mine workings or via the interception wells prior to entering the underground workings. The water collected in the mine workings is pumped to the mill where it joins the mill process water stream. The water from the Interception Wells is pumped into the Pothook TSF, where it becomes a component of process water. HATSF seepage water flows west from the northwestern portion of the facility to a seepage collection pond which maintains control of the water through evaporation and pump-back for processing. The mine site potable water treatment plant provides water to washrooms, kitchens, change room showers, and sinks across the site. Bottled potable water is brought on-site for drinking.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Consultant - Mining & Costs	Josh Parsons		Mar 7, 2025
Environmental & Permitting Manager	Luke Holdstock		Mar 7, 2025
General Manager	Jeffrey LaMarsh		Mar 7, 2025
Health & Safety Manager	Justin Clark		Mar 7, 2025
Maintenance Superintendent	Bryan Madsen		Mar 7, 2025
Mine Operations Superintendent	Tyler Roberts		Mar 7, 2025
Process Manager	Martin Froehling		Mar 7, 2025
Surface Superintendent	Matthew Davis		Mar 4, 2025