The Loulo and Gounkoto deposits can be classified as a typical shear hosted Birimian style mesothermal gold deposits. 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. The Loulo Mine comprises two main deposits, Gara and Yalea, and multiple satellites deposits. Gara Gara is located six kilometres NNW of the Yalea deposit and extends for 2.5 km within a tourmaline sandstone/greywacke unit, which outcrops over 800 m as QT forming low (10 m scale) topographic highs. Mineralisation averages 9 m width and 1.1 km depth. The mineralisation is hosted by a stockwork of quartz- carbonate-pyrite-tourmaline veinlets and associated disseminated pyrite, both of which are confined to a single bed of QT generally less than 30 m thick. The deposit lithologies from west to east are: limestone and argillaceous quartzite (SQR) in the hanging wall (HW), mineralised QT ranging from 5 m to 20 m thick (on average 15 m), and a coarse to medium grained greywacke unit in the footwall (FW). The sedimentary package is also crosscut by three un-mineralised late east-west trending dolerite sub-horizontal dykes that dip shallowly from north to south. The geometry of the deposit is dominated by the strike slip shearing and the development of associated conjugate sets of antithetic structures. This shearing has resulted in folding, fracturing, brecciation, and development of a quartz vein stockwork within the ........

The Loulo operation consists of two established underground mines, namely Yalea and Gara. A third underground mine, Gounkoto, recently commenced production and is currently in a ramp up phase. All three mines employ long hole open stoping with paste fill at a similar scale and all feed the same processing plant. The underground mines are accessed with twin declines at each site, after which stopes are accessed by multiple ramps developed at approximately 500 m intervals along strike. The sub-level spacing varies between 25 m and 20 m. Generally, newer areas are 25 m apart while older areas, crown pillar areas, and geotechnically complex areas are 20 m apart.

Yalea
The Yalea underground mine is a long hole stoping operation producing at a rate of approximately 1.4 Mtpa of ore. Development commenced in 2007, stoping commenced in 2008, and production has ramped up to 1.4 Mt in 2013.

The mine is accessed via twin declines starting in the Yalea open pits. One is a conveyor decline and the other is used for mobile equipment. The lower part of the mine has been developed through a number of single ramps for truck haulage up to crushers located approximately 350 m below surface which feed ore and waste onto the conveyors.

Gara
The Gara underground mine is a long hole stoping operation producing at a rate of 1.3 Mtpa of ore. Development began in 2010, with production gradually ramping up to 1.2 Mt in 2017 and 1.3 Mt in 2020.

Simi ........

The Loulo processing plant processes ore from both the Loulo and Gounkoto operations. The plant uses a conventional crushing, milling, gravity, CIL, and tailings disposal circuit.

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.

Since 2014, multiple optimisation projects have been undertaken, resulting in increased throughput and improved recoveries. The upgraded processing plant remains a conventional crushing, milling, CIL, and tailings disposal circuit.

• Crushing – three stage crushing circuit for the hard rock sulphide ores and a single stage roll toothed crusher for the soft weathered oxide ores.
• Milling – one primary mill (8 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 operate in closed circuit. An additional metal detector is installed on the feed to the tertiary crushers.

The secondary circuit consists of two Sandvik CS660 Hydrocone crushers and the tertiary circuit consists of four CH660 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 approximately 40,000 t and a total capacity of approximately 115,000 t. This is the feed to the primary 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 is composed of a ball mill operating as the primary mill (6.1 m diameter and 9.5 m effective grinding length (EGL) and installed motor power of 7,000 kW upgraded to 8,000 kW) in the open circuit. The oversize or scats are re-handled to the stockpile and re-crushed. The primary mill discharge feeds to two parallel single stage overflow type ball mills (5.5 m diameter 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 tph.

There is planned processing plant expansion scheduled to commence in 2027 which will expand the annual processing plant capacity to 6.2 Mtpa from 2029 onwards. The main expansion works, in parallel to the current flow sheet, will build an independent flow sheet of 4,200 tpd processing plant that include:
- A complete secondary and tertiary crushing circuit in closed circuit with the screening plant to produce a sub-12 mm product;
- A closed-circuit single stage milling circuit, comprising a 4.5 MW ball mill and a hydrocyclone cluster producing a P80 of minus 75 micron.

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