Orogenic gold mineralization at Kumtor is structurally dependent and formed penecontemporaneous with shearing on major faults through the system. Alteration associated with gold mineralization formed during several stages and at relatively high temperatures. The deposit is present along a continental-scale, amagmatic shallow-dipping (~25°-45°) structure cutting phyllite strata along the Kumtor shear zone. This structure is situated at the margin of the Middle Tien Shan terrain near the Nikolaev line – the Kyrgyz-Kazakh micro-continental suture.

Major features of the Kumtor Deposit compare favourably with those in prominent orogenic gold deposits present in black shale flysch strata such as Muruntau (Uzbekistan), Sukhoi Log, Olympiada and Natalka (Russia). However, contrasting features with these deposits include host-rock composition and age, age and grade of host rock metamorphism, age of mineralization, and presence or absence of magmatic rock, as well as degree and composition of associated alkaline metasomatism (sodium versus potassium). Nonetheless, the main distinctive feature of the Kumtor deposit versus other orogenic gold deposits hosted by black shales is absence of anomalous arsenic (>100 ppm) in mineralized rock. Another unusual feature of Kumtor mineralization is its large quantity of CaO gains, together with sulphur and CO2. This has resulted in a major presence of abundant MnFe-carbonate minerals in mineralized rock, accompanied with a relatively re ........

Mining is carried out using conventional open pit drill, blast, load, and haul operations. There are WRSFs currently in use and planned to be used for the remaining mine life, all of which require continuous management due to underlying foundation conditions and/or water inflow from adjacent glaciers. The Central, Southwest and Sarytor open pit rock masses are structurally complex with many faults and relatively weak rock mass, particularly the Central Pit; coupled with adjacent glaciers, this makes for a relatively complex mining situation requiring continuous geotechnical and water management. Over the remaining mine life Kumtor plans to mine 60.2 Mt ore and 1,641 Mt waste, have a peak mining rate of 205.6 Mt per year, average strip ratio of 27.2 waste:ore tonnes and continue until 2031.

In 2019, Centerra temporarily suspended open pit mining operations at Kumtor after a failure event at the Lysyi Valley WRSF. Due to the need to focus on search and rescue efforts as well as stabilize the WRSF, the operation was halted for one month. It is noted that the failure occurred in the then primary WRSF location causing further delay. In 2020, Kumtor Mine received all necessary approvals and permits to recommence operations and continue ore processing.

Open pit mining is performed using conventional open pit bulk mining methods with hydraulic shovels and mining trucks on 10-m benches.

The top mining elevation in the current ultimate pit design is at ........

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The process plant was originally designed with a capacity to process 4.8 Mtpy ore and is currently operating at 6.3 Mtpy.

The ore to be processed is managed through a number of stockpiles that receive ore with different metallurgical characteristics and of different grade ranges, as determined by grade-control data, and thus allows blending of the process feed for optimum gold recovery.

Hydro-cyclone overflow at 80% passing 150 microns gravitates to the flotation circuit, comprising 2 parallel banks of 9, 42 cubic metres (m3) naturally aspirated flotation cells. The flotation concentrate is thickened in a 15.2-m diameter concentrate wash thickener.

Ultra-fine grinding of flotation concentrate is completed in two stages. Flotation concentrate from the wash thickener underflow is first re-ground to 90% passing 20 microns in a 5.49-m diameter x 7.92-m long, 4,100-kW ball mill in closed circuit with-150 mm diameter hydro-cyclones. After thickening in the 15 ........