The Loulo and Gounkoto deposits can be classified as typical shear hosted Birimian style mesothermal gold deposits.

LOULO PERMIT GEOLOGY AND MINERALISATION
The Loulo project area is characterised by a sequence of sandstone, limestones and greywackes which are truncated by three major north to NE trending shear zones. Two major mineralised bodies have been discovered within the Project area, Gara and Yalea. Several other satellite deposits (Baboto, Gara West and Loulo 3) are also present.

The Yalea main mineralized body is hosted by the Yalea Shear, where it is intercepted by the Yalea Structure. The Yalea Shear is a 1.4-kilometer long brittle-ductile, north-south striking, mineralized fault that transects the Yalea Structure, which is a complex, north to north-northeast striking shear zone. The Yalea mineralization is predominantly hosted in hydrothermally brecciated argillaceous pink quartzites.

Gara is located 6 km NNW of the Yalea deposit and is hosted within 800 m long tourmaline sandstone/greywacke unit which outcrops on surface as black quartzite forming small (10 m) topographic highs. The host lithologies are (from west to east): chemical (limestone or carbonate altered) sediments and alternating argillitic and quarzitic bands (argillaceous quartzite or SQR) in the hanging wall, mineralised quartz tourmaline (QT) ranging from 5 m to 20 m thick (average 15 m) and a coarse to medium grained greywacke unit in the footwall. The sedimentary package is also crosscut by three unmineralised late EW dolerite sub-horizontal dykes that plunge shallowly from north to south.
Gold mineralisation is strata bound and hosted predominantly within the quartz-tourmaline sandstone unit which is enveloped within footwall greywackes and hanging wall schistose sandstone. Higher gold grades typically occur where the veining is most intense and the range of vein orientation more complex and are mostly in association with carbonate-pyrite. Mineralised veins also contain minor chalcopyrite, scheelite, rare earth element phosphates and nickeliferous sulphides.

Baboto is a shear hosted deposit situated along a north-south striking shear structure located approximately 14 km NNE from the Yalea deposit. This 5 km long structure contains the Baboto South, Centre and extends to Baboto North on a neighbouring permit.
Gold mineralisation is mainly associated with the finely disseminated pyrite occurring in the brittleductile shear breccias. These zones generally have a lensoidal shape defined by a series of subparallel N-S shears that follow the lithological contacts between the conglomerate, quartzite, and greywacke. The tabular pyrite or arsenopyrite does not correlate with gold mineralisation, while the fine acicular arsenopyrite is often associated with the mineralised zones. The hanging wall and footwall to the mineralisation are in general strongly foliated rock. The geological model consists of multiple sub parallel dilation structures hosting mineralised zones, which have a lensoidal shape.

Loulo 3 is located 4 kilometers north-northeast of the Yalea mine. Loulo 3 consists of four mineralized zones: a north-northwest trending main zone (“MZ1”), which is situated on the Loulo 3 structure and is transected by the north-northeast striking main zone (“MZ2”), which is situated on the Yalea structure, and two sub-parallel northwest striking footwall zones. The MZ2 mineralisation has an overall strike length of 1.8 km, ranges in thickness between 6 m to 12 m. Both MZ1 and the FW zone have smaller dimensions, being 580 m in strike, 5 m to 7 m thick and 200 m in strike, with 5 m thickness, respectively. The stratigraphy at Loulo 3 (inclusive of Loulo 2) comprises three major lithological sub units, which from east to west include: the hanging wall (“HW”) package (subunits HW1 to HW5), the host package (subunits HP1 to HP4), and the footwall (“FW”) package (subunits FW1 to FW2). The mineralization in Loulo is hosted in the HP4 subunit of the Main Sandstone package with a dominant vein-hosted mineralization style within MZ1 or quartz-tourmaline veins in MZ2. These vein arrays locally transition into bedding-parallel hydrothermal breccias with local semi-massive to massive pyrite, which can also include arsenopyite and hematite, and form the high-grade shoots within the Loulo 3 deposit.

Gara West is located in the hanging wall sequence approximately 400 m west of the Gara pit and is characterised by predominantly shear and breccia hosted mineralisation within a medium to coarse grained sandstone unit that is variably altered with tourmaline, chlorite, and silicacarbonate. The sandstone hosts four mineralised lodes striking NNE and dipping moderately westward. All mineralised zones are sub-parallel, striking NNE and dipping steeply westward.
The gold mineralisation is strata bound and hosted in strongly developed quartz carbonate vein arrays as well as associated disseminations and hydrothermal breccias within pink quartzite. The mineralisation exhibits a pinch and swell geometry at the scale of the deposit and have greater continuity along strike than at depth. Higher grades are associated with increasing intensity of quartz-carbonate vein development, carbonate-hematite-goethite alteration, and intensity of brecciation.

GOUNKOTO PERMIT GEOLOGY AND MINERALISATION
The Gounkoto Exploitation Permit (Gounkoto Permit) incorporates the Gounkoto and Faraba Reserves.

Gounkoto is a large north-northwest trending shear zone, with a complex assemblage of ductile shear breccias, shears and faults characterized by a stepped geometry, with wider zones of mineralization generally seen on the northwest trending structures and narrower zones on the north-south trending structures.
Gold is strongly associated with sulphide mineralisation, dominantly pyrite. Magnetite, chalcopyrite, arsenopyrite and pyrrhotite are also present locally and have a strong association with gold. Gold is also commonly found in gangue in zones of strong silica-carbonate alteration.

The Faraba deposit strikes NNW and is comprised of several zones of gold mineralisation hosted within and along the contacts of north-south striking, coarse grained, gritty sandstone units (lithic wackes) in a package of sheared argillaceous sediments. The host sandstones for mineralisation are arkosic grits comprised of plagioclase and quartz grains in a matrix containing dolomite and clay minerals. Lithologic layering (transposed bedding) dips steeply westward; however, the mineralised zones dip steeply to the east.
Mineralization is predominantly pyrite, with subordinate arsenopyrite, local magnetite, rare chalcopyrite and pyrrhotite. The mineralization is rheological competency contrast controlled and is typically vein-hosted (i.e. massive, stringers and blebs), or occurs as dissemination in strongly altered hosts (i.e. blebs and fine grains), with semi-massive to massive sulphides typically within the lower parts of the system adjacent to the Faraba Structure. Higher-grade portions of the system appear to plunge shallowly southward in longitudinal section.
The Faraba North target consists of a series of discrete shears and hydrothermal breccia, with vein-style mineralizations associated with pyrite and arsenopyrite. The mineralization zones are sub-parallel to stratigraphy and a total of eight mineralized zones have been generated in the HW domain, and two zones of Dip Domain Boundary (“DDB”) mineralization. The eight mineralized zones in the HW domain are characterized by strong hematite alteration within the first two zones. Then, silica albite, with minor tourmaline and chlorite alternation, for the next three zones, followed by silica carbonate dominant alteration in the lower most zones. The DDB mineralization is characterized by strong silica carbonate and hematite alteration.

The Loulo-Gounkoto Complex is currently comprised of open pits at Gounkoto, Faraba (which has yet to commence mining), satellite deposits: Baboto, Loulo 3 and Gara West. Additionally, the Yalea, Gara and Gounkoto underground mines are all currently in operation and are accessed via portals located in the open pits and a box cut.

OPEN PITS

Production from Loulo started in 2005 as an open pit operation, followed by the development of the underground mines.

Gounkoto, a greenfields discovery, poured its first gold in 2011, with its ore processed at the Loulo plant under a tolling agreement.

The Loulo Permit are comprised of the Baboto open pit, Loulo 3 open pit, and the Gara West open pit. Baboto oxide and free dig transition ore is scheduled to be mined in 2018, however the rest of the Baboto open pit fresh ore and the other pits will be mined from 2024 onwards, after the larger Gounkoto open pit is depleted. The production from these pits has not been extensively detailed. Randgold intends to use the same contractor that has already mined part of the Baboto open pit, so the fleet requirement is known. The Loulo 3 open pit was mined previously in 2013 and the eastern push back forms the remaining Ore Reserve. Both Loulo 3 and Gara West open pits will use the same equipment as they are timed to be mined consecutively.

Gounkoto is an on-going operation that applies selective mining. Ore is classified as either Full Grade Ore (FGO), delivered to primary crushers, or Marginal Ore (MO), which is stockpiled close to the primary crushers, and blended with the FGO to provide a consistent feed grade. The Gounkoto mining plan has been sequenced in such a way that the south pit will be mined out in advance of the north pit. This will allow the waste mined from the north pit to be backfilled into the south pit resulting in a shorter haul than the conventional route of tramming out of the pit and onto a waste dump. This, however, means excess ore must be mined in 2019 and stockpiled to ensure the plant feed requirements are maintained during the waste pushback mining in years 2020 to 2022.

Open pit mining is conducted by the contractor Gounkoto Mining Services (GMS), a local subsidiary of DTP Terrassement (DTP Mining), using either free-dig or conventional drill, blast, load, and haul methods.

UNDERGROUND MINES

The Yalea, Gara and Gounkoto underground mines are all currently in operation and are accessed via portals located in the open pits and a box cut.

Development of Gounkoto underground commenced in 2020 with the aim of mining the crown pillar under the North Pit during the second quarter of 2023. It adds high-grade ounces to Loulo-Gounkoto from 2023. The mining method for Gounkoto underground consists of long-hole bench stoping with backfill.

The declines were originally developed as twin declines. One decline containing a conveyor and the second decline is used for mobile equipment access. The lower part of the mines has been developed as single declines with truck haulage up to crushers which feed ore and waste onto the conveyors.

Three mining methods are used at the Yalea and Gara underground mines. They are long hole transverse open stoping; long hole longitudinal retreat open stoping; and stoping under rock fill (SURF). SURF mining is planned to be introduced in the weathered areas of Yalea South Upper.

The SURF method is planned for the portion of Yalea South Upper that has weathered transition or saprolite present in the mineralised zone, or the immediate hanging wall. The method will be used is expected to provide a more consistent production in the less competent ground.

From an operational perspective SURF is very similar to longitudinal sub level caving (SLC). The exception is that in SURF waste rock is tipped into the stope to fill mined voids and prevent caving of the hanging wall. In contrast SLC works by the hanging wall caving to fill the mined void.

In 2014 paste fill plants were commissioned. The paste fill plants at each of the mines produce a mixed paste / aggregate fill. With the introduction of paste fill the lower areas of the mines are being mined using an underhand (top down) long hole stoping method which retreats to central accesses in an echelon format. Panels are 50 m long, mined as single level stopes (25 m high) and filled with cemented paste fill. The paste fill is exposed by the mining of both the panel below and the next panel on the same level. Transverse long hole open stoping is used in the wider (>15 m wide) parts of Yalea North. Transverse stopes are 15 m to 30 m along strike and mined from hanging wall to footwall.

Ore material is crushed at Gounkoto with a primary Sandvik CJ815 jaw crusher and secondary cone Sandvik CS660 crusher. The final crushed product is minus 40 mm (80%) and minus 60 mm (20%) at a throughput rate depending on the final crushed size requirement. For the selected 35 mm product size the throughput rate is 360 tph.

The trucks transport ore from Gounkoto to Loulo, approximately 30 km away, using an average cycle time of 90 minutes. The trucks deliver crushed ore to the ROM pad at Loulo and feed the crushed ore directly into the hard rock circuit via the existing gyratory crusher.

Run of Mine ore from the shafts and Gounkoto operations are blended using detailed source analyses to provide a blend of ore to the plant for treatment, meeting the plant operating specifications. The ore is crushed in three stages of crushing to provide a suitable product for feed to the primary mill. Soft ore is fed to the mineral sizer, followed by ball milling. The mill products are classified using hydrocyclones, returning the course material underflow to the grinding circuit. The cyclone overflow is thickened to a suitable underflow density and pumped to the CIL plant.

• Crushing – three stage crushing for the hard rock sulphide ores and a single stage roll toothed crusher for the soft weathered oxide ores.
• Milling – one primary mill (7 MW); two identical single stage ball mills (4.5 MW), one scat conveyor system is inserted to return all mills scats back to primary mill via a cone crusher.

Crushing – Hard Ore
Hard rock is delivered to the tipping bin. Tipping can be completed from two directions.

The hard rock crusher plant consists of a primary gyrator crusher (FFE Minerals 1,300 mm by 1,750 mm) driven by a 450 kW electric motor. A tramp iron magnet is installed over the product conveyor to remove steel. A metal detector trips the conveyor if metal is detected.

The primary crusher operated at a rate of 700 tph, feeds the secondary crushers which operate in open circuit and then the tertiary crushers which operate in closed circuit. An additional metal detector is installed on the feed to the tertiary crushers

The secondary circuit consists of two Sandvik CS6800 Hydrocone crushers and the tertiary circuit consists of four H6800 Hydrocone crushing units, all are powered by a 315 kW electric motor. The secondary and tertiary crushers are housed in separate buildings connected via transfer conveyors.

The final product from the tertiary crushers discharges onto a reclaim ore stockpile, via a conveyor system, and has a live capacity of about 40,000 t and a total of approximately 115,000 t. This is the feed to the SAG mill.

Crushing - Soft Ore

A separate facility exists to crush the soft ore when it is available. The soft ore crushing consists of a tooth roll crusher (MMD 625 - 3 tooth) driven by a 250 kW electric motor. This feeds a separate stockpile area and the roll crusher product is fed directly onto the ball mill conveyor feed.

Grinding and Classification

The milling section produces a leach feed with approximately 75% passing 75 microns. The milling circuit comprises of a SAG mill operating as the primary mill (6.1 m dia. and 9.5 m EGL and installed motor power of 7,000 kW to be upgraded to 8,000 kW) operating in open circuit. The oversize or scats are re-handled to the stockpile and re-crushed. The primary mill discharge feeds two parallel single stage overflow type ball mills (5.5 m dia. by 8.0 m EGL) with a power rating of 4,500 kW each, operating in closed circuit with a dedicated cluster of twelve 250 mm hydrocyclones of which eight are typically in use.

An additional High Pressure Grinding Roll (HPGR) has been installed to treat scats at a rate of 100 t/h.

The Loulo processing plant uses a CIL gold extraction process with a throughput capacity of 4.8 million tonnes per annum.

Since 2014 multiple optimisation projects have been undertaken, resulting in increased throughput and improved recoveries.

The upgraded process plant remains a conventional crushing, milling, gravity, CIL, and tailings disposal circuit. However, the gravity circuit has been taken off-circuit since September 2017.
The upgraded process plant remains a conventional crushing, milling, gravity, CIL, and tailings disposal circuit.

The process plant uses the following circuits:

• Crushing
• Milling
• Gravity - four centrifugal primary concentrators followed by two intensive leach reactors to treat primary concentrates (the gravity circuit has been taken off-circuit since September 2017).
• CIL recovery process.
• Zadra elution process.
• Electrowinning.
• Tailings pumping/deposition split between slime dam and paste plant.

Gravity Concentration (the gravity circuit has been taken off-circuit since September 2017)

A bleed stream from each cyclone cluster underflow is diverted to its respective gravity concentration circuit.

In each primary concentration circuit, the feed slurry from the cyclone underflow is fed on a horizontal vibrating screen to remove material greater than 2 mm from the concentrator feed that would otherwise plug the concentrator bowl riffles.

Screen undersize from each cluster feeds Knelson XD-48 and QS-40 gravity gold concentrators after which the concentrates pass to a common feed hopper and Gemini dressing table located in the gold room. There is also the presence of an ILR1000 and ACACIA CS2000.

The mill products are classified using hydrocyclones, returning the course material underflow to the grinding circuit. The cyclone overflow is thickened to a suitable underflow density and pumped to the CIL plant.

Leaching and Adsorption

The CIL circuit consists of fourteen tanks that operate in series, each having a nominal capacity of 2,500 m3 giving a retention time of approximately 40 hours. Cyclone overflow, at a density of 35% solids, is introduced onto a linear trash screen (0.7 mm by 0.7 mm apertures) and the undersize goes to the leach feed thickener, the thickener underflow at a density of 50% presented as leach feed. Two pre-oxidation tanks receive the CIL circuit, each with six high-shear reactors (Aachen REA-400). Cyanide is added into Tank 2 and doses automatically to control concentration around the desired value with ± 2%. An oxygen dispersion system is installed to maintain optimal dissolved oxygen across CIL to assist leaching consisting of power mixers (EKATO in front tanks #3 to 7). The oxygen plant, operated by Air Liquide, supplies 44 tpd. Hydrogen peroxide is injected at the thickener underflow, as required, to maintain the required dissolved oxygen levels necessary for the process. Each CIL tank is fitted with a mechanically swept cylindrical inter-tank screen (0.8 mm) complete with pumping mechanism.

Fresh carbon is introduced to tank fourteen and is advanced to tank three in counter current flow to the pulp, using recessed impeller vertical pumps.

Elution and Gold Recovery

Loaded carbon is recovered from CIL tank 3 into the acid wash cone. After elutriation, it is acidwashed using a 3% hydrochloric acid solution, followed by a caustic neutralisation/water flushing step. The rinsed carbon is transferred to one of two elution columns where the caustic/cyanide solution is circulated at elevated temperature (135°C) and pressures using the Zadra process. Loulo carbon stripping consists of two parallel circuits from harvest - elution column – heater and exchanger to electro-winning cells at the gold room.

The pressure Zadra method utilises a pressure strip vessel that reverses the chemical equilibrium of the adsorbed gold-cyanide complex on the activated carbon resulting in desorption of the goldcyanide complex from the activated carbon into the strip solution.

The pressure Zadra process is conducted in a batch-by-batch process and requires approximately eight to 16 hours to complete.

The gold is then recovered downstream from the strip column by electro-winning. Six electrowinning cells are provided in the gold house for the electro-winning circuit where the pregnant electrolyte is introduced for gold deposition.

After each elution, the gold loaded stainless steel mesh cathodes are removed from the electrowinning cells and hosed down with high pressure water stream. This removes the plated gold onto a hopper where it is collected, settled, decanted and the sludge smelted after it has been dried in one of two electrically heated calcine ovens to produce doré bullion.

The barren carbon is now transferred to the adsorption circuit or to the carbon regeneration kiln where it is regenerated at C 700°C in a horizontal gas fired kiln.

The regenerated carbon is charged back into the CIL circuit.