Both the Tulkubash and the Kyzyltash mineralisation are classified as orogenic gold deposits. The Tulkubash mineralisation exhibits characteristics of shallow epithermal mineralisation,
and is further classified an epizonal orogenic deposit. The Kyzyltash mineralisation formed in a much deeper environment and is classified as mesothermal orogenic gold deposits.

The Chaarat Property, located within the Middle Tien Shan Province, locates within the Tien Shan Metallogenic Belt, a Hercynian fold and thrust belt that crosses Central Asia.

The Sandalash River valley down cuts a northeast-trending sequence of Cambro-Ordovician siliciclastic sediments which comprise the Chaarat Formation. This in turn is overthrust by a sequence of younger Devonian-age quartzites which make up the Tulkubash Formation. The sedimentary rocks hosting mineralisation strike north-easterly and exhibit dips between 40° and 75° to the northwest. Younger, Permo-Triassic-age granodiorite and diorite phases intrude the sediments and are closely associated with the gold mineralisation and, in some areas, are themselves mineralised.

Mineralisation and associated hydrothermal alteration at Chaarat are genetically associated with igneous intrusive rocks along a system of regional-scale, sinistral, oblique-slip faults. Within this setting, there are two distinct types of mineralisation: the Tulkubash-type and the Kyzyltash-type. However, the proximity of the two types of mineralisation and the common structural controls suggest that both were the result of a common hydrothermal event.

The Chaarat Formation is made up of three members which exhibit a sequential package of alternating, moderately- to well-bedded, dark coloured, siltstones, shales, quartzites, and greywackes, with minor limestone interbeds. The lower member is up to 170 m thick, consisting of grey siliceous siltstone interbedded with minor dark siltstone and shale. The middle member is approximately 300 m thick. It consists of interbedded fine- and mediumgrained sandstones, greywackes and siltstones, with a basal zone consisting of lenticular beds of polymictic gravely conglomerates and sandstones. The upper member is dominated by shales and rhythmically interbedded siltstones and finegrained sandstones which commonly exhibit graded bedding. The member is 70 m to 90 m thick whereas the thickness of individual beds ranges between 1 m and 2 m.

The Chaarat Property lies within the Sandalash Fault Zone (SFZ), a zone defined by a series of subparallel brittle shear zones that are the result of the local, predominantly sinistral strike-slip, displacement of the SFZ. The gold mineralisation occurs in various extensional structures, related to pressure relief during faulting (Kramer 2009; Jakubiak 2017). The SFZ comprises three mineralised fault zones, namely the Tulkubash Structural Zone, the Contact Fault, and the Main Zone Fault as well as one unmineralised zone called the Irisay Fault.

Gold mineralisation within the Chaarat Property is divided into two styles of mineralisation:
- The Kyzyltash mineralisation, which is divided into the Main and Contact zones. This mineralisation is sulphide-rich and refractory; and
- The Tulkubash mineralisation, which is oxidised and can be processed through conventional heap leach methods.

The Tulkubash mineralisation is the primary subject of this feasibility study; however, the Kyzyltash mineralisation is briefly described for completeness.

The Tulkubash zone is a mineralised structural zone that trends northeastsouthwest and dips steeply 55° to 75° to the northwest. The Tulkubash zone is interpreted to be a brittle shear zone that developed as the result of predominately sinistral strike-slip motion within the SFZ. Gold mineralisation within the Tulkubash zone occurs within zones of intense silicification and quartz flooding, which form individual gold-bearing lodes that can range from 5 m to 45 m in true thickness. Where multiple lodes are present, the Tulkubash zone can have a width of up to 250 m with the individual lodes separated by unmineralised country rock. Development drilling of the Tulkubash deposit indicates that the zone is remarkably continuous, however its thickness does vary along strike.

A distinctive feature present in areas of strong mineralisation are ovoid shaped hydrothermal breccias which are interpreted as fossilised steam vents. They form resistant spires up to 10 m high and 5 m to 10 m in cross section. The breccias are clast-supported with less than 5% carbonate cement and are easily identified in outcrop by the distinctive preferential growth of lichens on the carbonate cement. The breccias are typically barren but occur within areas of strong gold mineralisation. Goldbearing lodes are characterised by red and red-brown hematitic iron oxides, with minor yellowbrown limonite, and rarely occurring jarosite and stibiconite. The Tulkubash zone is largely oxidised with low oxidation material occurring at the base and more strongly oxidised material at the top. The contact between unoxidised sulphide ore and oxidised ore can be gradational but is often observed with a sharp contact, suggesting at least some of the oxidation is hypogene.

Using Tulkubash composites, gold particles are identified in heavy liquid separates (Kirchner and Coetzee 2011). The gold occurs as electrum containing a low silver content, typically ranging between 4% and 8%, with a few grains at 16% silver. Silver was also observed as silver-rich tetrahedrite and within a silver-rich lead-antimony-sulfosalt. The widespread silicification and deep oxidation is in distinct contrast to the Kyzyltash zone, where minor quartz occurs in thin veinlets with no significant oxidation.

The Kyzyltash zone is a series of sulphide-bearing ore bodies made up of the Main zone and Contact zone mineralisation (Figure 7-6) and locates to the East and northeast of the Tulkubash Zone. The mineralised zones occur within two subparallel northeast-trending structural zones that have been traced for 10 km along strike. The ore consists of goldarsenopyrite-stibnite- tetrahedrite mineralisation occurring in sheared and altered wall rock. The ore exhibits strong sericitic alteration, with lesser amounts of quartz, quartz vein stockwork, ankerite, and calcite gangue. In some areas, antimony and silver are significant constituents of mineralisation, the latter particularly in the Contact zone and in the M7000 ore body (about 21 g/t silver average). Antimony, in stibnite and various sulfosalts, can locally reach values of 10% or more over 1 m to 2 m thick zones. Trace amounts of copper and molybdenum are also present in some of the ore.

Petrographic work completed by Chaarat on more than 50 thin sections showed that free gold is present in the ore and occurs as inclusions in quartz and arsenopyrite. The gold mineralisation is, to some extent, correlated with arsenic, which mostly occurs as arsenopyrite. In some localised zones, there are very high silver values (greater than 400 g/t silver). The distribution of silver values is not fully understood, and transitions from silver-rich areas to silver-deficient areas can occur over distances of less than 20 m along strike.

The following associated overall slope geometry was recommended by WAI:
- Berm width: 5.5 m;
- Bench height: 15 m;
- Bench face angle: 66° and 75°;
- Inter-ramp angle: 51° and 58°; and
- Geotechnical berm: 9.5 m.

The bench face angles in the final designs vary between 60° and 75°, with 8 m berm widths to comply with local regulations and to allow mechanised cleaning. The inter-ramp angles (IRA) of around 51° and 58° for the various design sectors (i.e., Sectors 1 to 4), were flattened slightly to accommodate bench width and aligned with the WAI bench geometry recommendations. The IRA for the fault zone was reduced to 45°.

In the revised 2020 pit design it was noted that the final highwall reaches a height of 375 m, a moderate highwall height increase of approximately 1.4%.

The Tulkubash 2020 EOY open pit design is composed of three separate pits arranged along the strike of the orebody over 2 km. The pits are situated in steep, mountainous terrain at elevations of 2,300 masl to 2,800 masl. The deposit is divided up into two zones, the Main Zone and the Mid Zone.

The Main Zone Pit is situated at the southwestern end of the mining area. It is the single largest pit accounting for over 90% of the reserve by both tonnage and contained gold. The Main Zone Pit hosts a reserve of 19.4 Mt ore grading 0.86 g/t Au, containing 538 Koz Au. Associated with the ore is 50.4 Mt of waste resulting in a strip ratio of 2.6:1 (t:t). The Main Zone Pit is approximately 1.3 km in length. The width of the pit varies from 530 m at the south end and 370 m in the central portion before narrowing to 130 m at the northeast end. The crest of the final pit lies at an elevation of 2,740 masl while the elevation of the final pit bottom is 2,365 masl resulting in a maximum vertical extent of 375 m at the south end. Overall, the final highwall ranges between 250 m to 300 m in height. The Main Zone Pit exhibits a single pit bottom at the south end of the pit and two other lenticular bottom benches arranged along strike as the pit moves to the northeast. Most of the benches in the pit intersect surface contours except for the bottom 40 m to 50 m.

The Mid Zone Pit design is composed of two separate small open pits. These pits are arranged along strike length about 150 m northeast of the Main Zone Pit. The Mid Zone accounts for approximately 7% of the reserve by tonnage and 6% of the contained gold. The Mid Zone Pits host a reserve of 1.4 Mt ore grading 0.72 g/t Au, containing 33 Koz Au. Associated with the ore is 3.7 Mt of waste resulting in a strip ratio of 2.6:1 (t:t). The first Mid Zone pit is roughly circular with a diameter of about 150 m and a depth of 120 m. The second Mid Zone pit, located immediately to the northeast is bigger, being about 350 m in length, 150 m wide, and 150 m deep. Although small and lower grade than the Main Zone, the Mid Zone Pits offer the highest metallurgical recovery in the reserve, over 76%.

The deposit will be developed and mined using conventional hard rock open pit mining techniques. Mine development will entail establishing large enough working areas in the open pit to enable safe and efficient mining operations at production rates that are high enough to support a steady state supply of ore for processing. All vegetation and organic material will be cleared and deposited in designated stockpiles (SP) to be used in the future for rehabilitation and mine closure. Topsoil will similarly be stripped and stockpiled separately and will be used to rehabilitate the area once mining is finished.

Once access to the initial bench elevation is established, dozers will level a large enough area to allow blasthole drilling. This initial platform will then be drilled and blasted, dozed down, and the process repeated until a bench wide enough (15 m) to accommodate single-side truck loading is established. Steady state production benches will be at least 25 m wide. The drilling and blasting of 5 m benches will commence and waste rock will be used to widen haul roads pioneered to the waste dumping areas. Once the initial working areas are sufficiently developed to support steady state production, mine development work will progress along strike. It is in this manner that the open pits will be developed along strike across the hillside with access development, bench development, and steady state mining following each other in a continuous sequence.

Haul roads connecting the open pit area to the Sandalash River Bridge and the waste dump will be constructed during pre-production. The cost of these roads has been designated as part of the project capital expenditure.

The mining plan calls for 4.6 years of production mining preceded by 13 months of pre-production stripping, a total of 68 months. Total mined tonnage over the LoM, including pre-stripping, is 74.9 Mt with an average mining rate of 13.0 Mtpa or about 37,000 tpd. The mining rate peaks in 2025 at 18.5 Mtpa or about 53,000 tpd. During the 13-month pre-production period, 7.4 Mt of material is mined including 600 kt of ore. 409 Kt of this ore is sent to the HLF, including the material for the overliner. The remaining approximately 185 Mt of ore is stockpiled for processing later in the LoM.

The ore process rate at full production is 4.9 Mtpa. In years where mining exceeds this figure, ore is stockpiled. In years where ore mined is less than the process rate, ore is reclaimed from the stockpile. Stockpiling and reclaiming ore allow the schedule to manage annual variations in ore and waste mining from the open pits.

The crushing facility will be designed to have 85% availability, and 82% utilisation, to yield a 70% effective utilisation. However, higher crushing facility runtimes are expected to be achieved during the steady state operation of the plant.

The ROM pad will have a capacity of 33,122 m³ based on a stockpile height of 12 m and an angle of repose of 37 degrees. This corresponds to approximately 63,000 tonnes at an average RoM bulk density of 1.90 t/m³. This will be sufficient for routine storage purposes and for a major interruption to mine supply of up to about 4 days, based on a processing rate of 13,500 t/d.

A conventional three-stage crushing circuit will crush ROM ore to a P80 of 12.5 mm, at a rate of 13,500 t/d. Lime is added to the crushed ore before it is transported to the heap leach pad.

Run-of-Mine (ROM) ore is delivered by 30 tonne haul trucks to the primary crusher. The trucks dump on to 700 mm aperture stationary grizzly installed over the truck dump hopper. This hopper has a live capacity of 70 tonnes. Oversize rocks will be broken by a mobile rock breaker. Space has also been allowed for a future fixed rock breaker.

The hopper has two-sided access. One side will be in continuous use by trucks and the other will be for a mobile rock breaker and may be used by trucks if necessary.

The ore is withdrawn from the dump hopper via an 1800x8800mm apron feeder, which supplies material to a 1.6 m x 4.5 m vibrating grizzly. The vibrating grizzly oversize is directed to a C150 jaw crusher, which reduces the rock size to 80% passing 180mm prior to being conveyed by the secondary cone crusher feed conveyor to the secondary crusher.

A self-cleaning belt magnet is installed over the conveyor belt which feeds the secondary crusher. The vibrating grizzly screen undersize is conveyed to the by-pass screen building. The bypass screen is a low head high “G” double deck screen with an upper deck aperture size of 35mm and bottom deck selected to produce a 14 mm separation, corresponding to the desired product size of 80% passing 12.5 mm. Both decks comprise modular panels made of abrasion resistant rubber.

Screen undersize (minus 12.5 mm material) is conveyed by a transfer conveyor to the tail end of the final product conveyor, which feeds the fine ore stockpile. Bypass screen oversize material (i.e. plus 12.5 mm) is conveyed back to the secondary crusher feed conveyor upstream of the belt magnet. Both primary crushing and by-pass screening take place in enclosed buildings.

Primary crusher product and by-pass screen oversize material are combined and fed directly to the secondary cone crusher. The secondary cone crusher discharge product is transported to the screen feed bin in the screen house building by the screen feed conveyor.

The screen feed bin supplies two 3 m x 7.2 m double deck banana screens which screen at a separation of 35 mm (top deck) and 15 mm (bottom deck). The oversize material from the product screens reports to the crusher feed conveyor via a transfer conveyor. This conveyor discharges into the tertiary crusher feed bin, which has a live capacity of 125 tonnes.

Two belt feeders installed under tertiary crusher feed bin supply two parallel tertiary cone crushers. Space has been allowed for a future third tertiary crusher. The discharge material from the tertiary cone crushers reports to the screen feed conveyor, where it combines with the secondary crusher discharge and delivers crushed ore to the product screen feed bin.

The fine ore stockpile is an open stockpile and it is designed for live capacity of approximately 10,000 tonnes. A reclaim tunnel underneath the stockpile is of a multi-plate steel culvert type construction. Three belt feeders in the tunnel withdraw material from the stockpile and discharge onto the truck loading conveyor belt. Truck loading will be controlled by the appropriate instrumentation.

The mobile crusher will be positioned at the mine.

A conventional three-stage crushing circuit will crush ROM ore to a P80 of 12.5 mm, at a rate of 13,500 t/d. Lime is added to the crushed ore before it is transported to the heap leach pad. Trucks will haul the crushed ore to the heap leach pad where it will be stacked in 7 m lifts.

The prepared areas of ore on the heap leach will be irrigated with a dilute cyanide solution at a rate of 10 l/m2 /h to dissolve the gold and silver from the ore into the solution. Once the solution percolates through to the base of the pad, it gravitates to the pregnant leach solution (PLS) pond. From there, it is gravity fed to the ADR plant for gold and silver recovery; however, a pump is used to begin the siphon process. The precious metals from the pregnant solution adsorb on to granular activated carbon in the CIC circuit (‘Carbon in Column’) of the ADR plant. After passing through the CIC tanks, the solution now depleted in gold (barren solution), is recirculated back to the heap leach pa ........