The Red Lake operation is an underground mine, operating in three different historical mining complexes (Red Lake, Campbell and Cochenour) and the recently acquired Bateman Gold Project.

The Campbell-Red Lake and Bateman gold deposits are located within the Red Lake greenstone belt of the Superior Tectonic Province. This belt is host to one of Canada’s largest and richest Archean gold deposits producing more than 26 million ounces of gold since the 1930s. The Red Lake Greenstone Belt is subdivided into several rock assemblages recording magmatic and sedimentary activities that occurred from 3.0 to 2.7 billion years before the present. The tholeiitic and komatiitic metabasalts of the Balmer Assemblage are the oldest volcanic rocks in the belt and are host to the major gold deposits in the Red Lake district, including the Campbell-Red Lake and Bateman deposits.

Gold mineralisation is mainly associated with silicification and sulphide minerals that replace carbonate veins, breccias and wall rock selvages. The carbonate veins and breccias, which are composed of ankerite ± quartz, were formed before and/or in the early stage of penetrative ductile deformation, whereas silicification, sulphide replacement and gold mineralisation were coeval with deformation.

The Cochenour Complex covers mineralization discovered at the Western Discovery Zone deposit and the former Cochenour–Willans mine. It also includes the former Gold Eagle Mines Joint Venture property; host to the Bruce Channel deposit and the former Gold Eagle mine.

The mineralization within the Red Lake Mines can be classified as an Archean greenstone belt- hosted gold deposit.

The majority of the mineralization in these types of deposits is intimately associated with quartz ± carbonate (calcite, ankerite, or siderite) veins with persistent sericite–carbonate alteration haloes in highly deformed, Archean host rocks that have been regionally metamorphosed to lower or middle greenschist facies. The host rocks are highly-altered, supracrustal rocks; most commonly tholeiitic basalts, komatiites or their volcaniclastic or subvolcanic equivalents. Mineralization also occurs in felsic volcanic rocks, porphyries, greywackes and conglomerates.

The Red Lake-Campbell Deposit can be accessed though the Red Lake and Campbell Complexes. It has approximate deposit dimensions of 2.2 km north–south, 3.2 km east–west, and remains open down-dip and along strike. Mine workings extend to 2,360 m depth (52 Level), with the deepest drill intercept currently at around 2,600 m depth.

Mineralization is primarily localized within the tholeiitic mafic rocks and shows strong structural control along broad to discrete shear structures running along a 135° trend in the east, refracting to a 120° trend in the west. Other significant mineralized zones occur along discordant brittle structures which most commonly appear as a conjugates system generally oriented east-west (110° azimuth) and north–south (160° azimuth). Competency and permeability contrasts between adjacent lithologies is also important as seen by the strong association of higher-grade mineralization when basalt comes in contact with ultramafic rocks.

Mineralized zones in the Red Lake-Campbell deposit are distinguished first by spatial orientation relative to structural corridors and second by the style of mineralization. It is common for mineralized zones to have multiple styles of mineralization within the same host lithology. There are four types of mineralization in Red Lake-Campbell Deposit:
1) Vein style gold mineralization;
2) Vein and sulphide style gold mineralization;
3) Disseminated sulphide style mineralization (often referred to as replacement style mineralization), there are sub-styles within this group;
4) Free gold mineralization style.

The Cochenour can be accessed by the Cochenour Complex and is connected underground to the Campbell Complex. The Cochenour Deposit covers an area that is approximately 750 m by 500 m and remains open down-dip. Mine workings extend 1,800 m (5320 Level). The deposit remains open down-dip.

The Cochenour Deposit comprises the Main, Inco, Upper Main Zone (UMZ), Banded Iron Formation (BIF), Footwall and new exploration targets. The Main and Inco zones form part of the original Cochenour Mine. The Western Discovery exploration target is located on McKenzie Island, approximately 1.5 km due west of the Cochenour mine site and will be included in the Cochenour Deposit.

The Cochenour deposit appears folded about a southwest-trending antiform, plunging to the southwest at 50° immediately in the hanging wall of the East Bay deformational corridor. A series of massive, felsic tuffs, reworked tuffs and felsic intrusions occurs along the western flank of the former Cochenour mine, which makes up the base of the overlying Bruce Channel assemblage. At surface, these rocks define the location of a north–south running shear zone, referred to as the Gold Eagle Shear, which dips steeply due west at approximately 65° underneath the Bruce Channel of Red Lake.

Mineralization in the Cochenour deposit is made up of the same styles as the Red LakeCampbell deposit. Mineralized zones in the Cochenour deposit are distinguished first by spatial orientation relative to major structural and by the style of mineralization.

Cochenour Main and West Zones
Mineralization is associated with discrete shear structures immediately in the footwall of the Cochenour Thrust structure. The geometries of this mineralization was complicated by numerous roughly north–south, steeply-oriented fault structures, as well as by numerous roughly east–west trending, steeply-dipping, very narrow (1 to 5 mm), brittle offset structures referred to as “black-line faults”.

This mineralization type occurs within sheared ankerite-altered iron-tholeiitic basalts and ankerite veins, with higher-grade mineralization located in close proximity to peridotitic rocks. Mineralization consists of intense late, vitreous silica replacement accompanied by a significant component (locally up to 30%) sulphide minerals. The most common sulphides include fine needle- like arsenopyrite, pyrite–pyrrhotite, with minor sphalerite, chalcopyrite and stibnite. Gold occurs as both free-milling gold as well as refractory grain coatings on fine arsenopyrite grains.

Inco Zones
Mineralogy is very similar to that located in the Cochenour Main/West Zones, and consists of intense late silica replacement accompanied by a significant component sulphide mineral replacement (fine needle-like arsenopyrite, pyrite/pyrrhotite, with minor sphalerite, chalcopyrite and stibnite). Gold appears as free milling gold as well as refractory arsenopyrite associated gold.

Bruce Channel Deposit (Upper Main and Footwall Zones)
Footwall Zone structures appear as a series of steeply-dipping, fault-hosted, ~160°-trending, sheared carbonate vein structures that are generally developed in the footwall to the UMZ. These Footwall Zone structures share many features in common with the north–south shear structures associated with the Inco Zone mineralization, and are probably directly related to the same suite of ~160°-trending narrow shears found higher up in the mine.

Upper Main Zone structures currently extend vertically for about 1,000 m and locally have strike lengths as long as 550 m. Mineralization is typically 2–5 m wide, but can occur as broader, structurally-stacked zones.

The Red Lake operation is an underground mine, operating in three different historical mining complexes (Red Lake, Campbell and Cochenour) and the recently acquired Bateman Gold Project which has consolidated the mining region and provided significant opportunities to maximise production and margins. Data integration and orebody re-modelling work will be undertaken and a new mine plan developed.

Red Lake, Campbell and Cochenour are interconnected underground. Access is through three shafts: Cochenour, Reid and No. 3 shafts. The primary mining method is sublevel open stoping, along with traditional and modified Avoca methods. Ore and waste is moved via internal passes, trams and ramp trucking. Ore is hoisted to surface through two production shafts, Reid and #3 Shaft. Ventilation is a push-pull system consisting of 4 intake and 5 exhaust fans and 15 underground booster fans.

Mining is carried out with a company-owned fleet of mining equipment, supplemented by contractor production drills.

Red Lake Processing Complex
The crushing plant is a two-stage process which reduces underground ore from about 30 cm to 1 cm. Underground ore from a coarse ore bin is fed to a jaw crusher and sizing screen. Screen oversize is crushed in a cone crusher and screen undersize is conveyed into a fine ore bin as plant feed material.

In 2007, an expansion to the mill was completed, which consisted of a reclaim facility to receive ore from the #3 Shaft, a new verti-mill, and upgrades to mill pumps and tanks.

Campbell Complex
The ore is hoisted from the Reid Shaft to a 1,300 t coarse ore bin. From there, it is transferred to a 250 t coarse ore bin located in the Campbell Mine head frame. The crushing plant consists of two Ross feeders, jaw crusher, standard cone crusher, short head cone crusher, Tyler double deck screen, variable speed short feeder belt, and six conveyors.

A 19 mm product is produced in three stages of crushing at an average rate of 140 t/h. A jaw and standard cone crusher operates in open circuit and a short head cone crusher operates in closed circuit with an 18 mm vibrating screen. The closed side setting of the standard and short head cone crusher is approximately 19 mm and 15 mm, respectively.

Fine ore is conveyed to the mill by inclined conveyor discharging, via a conveyor, to a 3,100 t fine ore bin.

Grinding is achieved in a two-stage rod/ball mill circuit. The ore from the fine ore bin is fed to the rod mill via two slot feeders and a conveyor. The grinding circuit consists of a 2.74 m x 3.8 m rod mill and 3.8 m x 4.7 m ball mill discharging, through trommel screens, into a common primary pump box.

The Campbell Mill uses conventional crushing and grinding which is followed by gravity concentration to recover freemilling gold. Refractory gold is recovered by flotation followed by pressure oxidation, neutralisation and CIL. Current capacity is 800ktpa and is planned to increase to 1.1Mtpa by 2023.

The Red Lake Mill was successfully commissioned in February 2021 (previously on care and maintenance) and has a current capacity of 300ktpa.

The new Bateman Mill (currently on car and maintenance) has a nameplate capacity of 650ktpa and is currently permitted to 450ktpa. It may be expandable to 900ktpa with minimal expenditure.

Red Lake Processing Complex
The original Red Lake mill was built in 1948, but was dismantled in early 2000, making way for a completely new mill. The new process facilities consist of three separate plants: the crushing plant; processing plant; and paste fill plant. Commercial production from the facilities began on January 1, ........