Tasiast gold deposits are hosted in Archaean volcanic-sedimentary sequences that have been deformed and metamorphosed to lower amphibolite peak metamorphic grade. Mineralization is both structurally and lithologically controlled, epigenetic in style and was coincident with early stages of post-peak metamorphic retrograde Greenschist P-T conditions.

The Tasiast gold deposits fall into the broad category of orogenic gold deposits. The regional geological setting and deposit features at Tasiast are similar to other wellknown Archaean lode gold deposits hosted along greenstone belts in granitoidgreenstone terranes.

The Tasiast deposits are hosted within a package of strongly foliated and folded rocks in the hanging wall block of an assumed thrust fault or thrust fault system referred to as the Tasiast thrust system. Modelling and interpretation of high-resolution gravity data shows deep geometry suggestive of a thrust system underlying the Aouéouat belt. The Tasiast thrust system displays zones of strong deformation typically 0.5 m to 10 m wide and characterized by laminated foliation with locally preserved mylonitic textures. Hydrothermal alteration assemblages, sulphides and quartz veins are commonly spatially associated with the zones of intense deformation.

All of the Tasiast deposits host an intense, generally N-S striking, variably dipping, penetrative foliation, S1, which is axial planar to tight isoclinal folds in the host sequence (Davis, 2018). The foliation fabric within the main mine sequence, at West Branch, dips moderately to the East at 40-50°, steepens to the North to 55-65° at Piment and becomes sub- vertical, at the north end of the mine sequence, near Prolongation.

Pit mapping at Tasiast includes the collection of structural fabric measurements for structural geology and geotechnical application. Numerous consultants have assisted Kinross in developing a structural model for the Tasiast deposits along with developing pit mapping procedures. Most recently, in 2018, Dominique Chardon worked with the Mine Geology department to review and analyse the significant database of structural data collected from pit mapping activities.

Quartz-carbonate veins sets occur sub-parallel and oblique to foliation and range in style from boudinaged, buckled, folded to planar. The veins clearly formed in extensional and/or Riedel shear orientations and were progressively folded, rotated, locally boudinaged and partially or wholly transposed parallel to the foliation. In the core of the West Branch Greenschist Zone vein, densities are typically higher in the meta- intrusive dioritic unit (averaging between 2% to 5%) than in the meta-basalt (<2%). This higher density suggests the coarser-grained feldspar- rich dioritic facies focused stresses and readily developed brittle-ductile shears, as expected for quartzofeldspathic rocks under retrograde Greenschist metamorphic conditions. Along the margins of the West Branch deposit, both the dioritic and meta-mafic volcanic units have a low vein density (<1%). Quartz-carbonate veins also developed locally within FVC that envelops the Greenschist Zone and within the footwall meta- sedimentary units.

Gold occurs as both microscopic grains and coarse visible gold. When observed in hand specimen, grains are commonly spatially associated with hairline fractures in quartz veins and margins of sulphide minerals. The majority of the quartz veins containing coarse visible gold cut the foliation at a slightly oblique angle and mainly dip gently to the east. The majority of gold grains occur along the margin of the gangue and ore minerals, with 98% of the calculated volume/mass of the grains occurring in liberated and partially liberated forms. By volume/mass calculations, the majority (greater than 70%) of the volume is associated with the coarser (plus 75 µm) size fraction. Encapsulated gold grains are rarely observed. When present they are predominantly a very fine grain size. Semi- quantitative scanning electron microscopy analysis of gold grains indicated low silver (less than 15%) and trace iron (less than 3%) content.

Ore and waste rock is mined in 10 metre benches by conventional open pit methods primarily from the West Branch pit. Tasiast currently operates a load and haul fleet of 46 CAT 793D (220 ton) trucks, five Komatsu 785 (92 t) and five CAT 6060 shovels plus two RH340B excavators. Blasting techniques, including presplit and buffer hole blasting, are employed to protect the pit walls.

Ore and waste rock is mined by conventional open pit methods from two pits (West Branch and Piment). Prior mining has taken place in West Branch, Piment and several other smaller pits at Tasiast. From September 2010 when Kinross acquired the property to the end of 2019, a total of 637 million tonnes of material have been mined from various pits, including 53 million tonnes in 2016, 75 million tonnes in 2017, 87 million tonnes in 2018 and 85 million tonnes in 2019.

The existing shovel and haul truck fleets will be used for the duration of mining and no replacement of this equipment is anticipated. Equipment life has been projected from actual operating hours, with estimates of future usage based on the mine plan.

Waste rock is used for haul road and tailings dam construction as needed. The existing road network is well developed, and requires continued maintenance. Additional roads will also be required throughout the life of the mine. These roads will be constructed using the current mining and support mining fleets.

Primary Crushing
Mined ore above plant feed cut-off grade is transported from the open pits to the plant by truck and either deposited onto the ROM pad or directly dumped into a Gyratory Crusher.

Crushing of the mineralized material takes place in a single stage; a primary gyratory crusher that reduces rock to less than 210 mm. The rock is conveyed to a coarse ore stockpile that uses three apron feeders to feed the 40 ft SAG mill.

Grinding
The SAG mill works in closed circuit pebble crushing with a circulating load of up to 40%. The SAG mill is also in closed circuit with a cyclone cluster. Cyclone overflow is pumped to two, parallel Ball Mills. The Ball Mills are in closed circuit with cyclones. The target grind size is 80% passing 90 µm. Cyclone overflow containing solids of the required size flows to linear trash screens prior to entering the leaching circuit. Coarser solids are returned to the mill for further grinding, with a bleed to a gravity circuit to capture liberated, coarse gold particles.

The existing Tasiast CIL plant has proven capable of processing approximately 15 kt/d. Kinross has decided to increase the existing CIL plant capacity in stages through a debottlenecking exercise. The modifications to achieve and initial target of 21 kt/d and later 24 kt/d form the basis of this project and are detailed below.

The existing CIL processing plant produces the majority of the gold shipped from Tasiast. The remaining gold is produced from the dump leach operations via a dedicated ADR plant. All produced gold is in the form of bullion and is transported regularly to a refinery for final refining and sale.

Unit gold recovery estimates for the existing plants are based on metallurgical test work and a review of historical performance. The recovery varies by mineralization type, lithology and grade.

Dump Leach Pads
The dump leach operation is nearing the end of its life. Rinsing of the pads is expected to begin in early 2020 and take appr ........