Centerra Gold Inc.

Exploration, Drilling; Sampling, Analysis and Data Verification

Since acquiring the Kemess Project, Centerra has conducted various exploration programs in 2019, 2020, 2024 and 2025, at both Kemess North and Kemess South, including geophysical surveys and diamond drilling campaigns.

Diamond drilling at the Kemess Project totals over 350,000 metres of drill core in more than 950 drill holes, and was designed for mineral exploration, resource delineation and infill, to obtain metallurgical samples, to condemn areas planned for infrastructure, and to gather geotechnical and environmental information. Since 2019, Centerra has completed 59,293 metres of diamond drilling in 147 drill holes at Kemess North and Kemess South.

The 2019–2025 drilling by Centerra has continued to define the Kemess North mineralization trend, an east-westerly striking prospective belt of porphyry deposits, over 3.8 km in length, with variable depths from surface. From west to east the trend includes the Nugget, Kemess Underground, Kemess Main, Kemess Offset, Kemess East, and Hilda South targets, with a general trend of deposits occurring at greater depths towards the east. In 2025, drill programs totalled 31,936 metres in 96 drill holes, including at Kemess Main (open-pit and underground) to infill within the resource shell and to expand resources to the west. The 2025 program at Kemess South included 10 holes to confirm historical geological modelling and interpretations, as well as to test for potential mineralization on the western margins of the historical Kemess South open pit.

From 2019 to present, drill samples were cut at the Kemess Project site and half-core samples were sent to BV in Vancouver, British Columbia for sample preparation and pulverization. At BV, all drill core samples were analyzed for precious and base metals, as well as multi-elements. Further to the QA/QC procedures implemented for the 2017–2025 drilling programs, routine data checks are performed to ensure the assays in the drill hole database are checked against assay certificates received by the lab. All the Kemess Project drill core is stored at the Kemess mine site.

Since 2011 there have been 10 metallurgical testwork programs, the most recent being in 2025. Five major mineral types and two waste domains were previously defined in the Kemess Underground. Testwork has been completed on material from both the Kemess Underground deposit and Kemess Main. The results establish the comminution design parameters, flotation performance expectations, and metallurgical recovery assumptions applied in the study. The 2025 test program provided additional mineralogy, comminution, and flotation data specifically for the Kemess Main material, intended to be mined by open pit and which forms the majority of the planned mill feed.

The Kemess Project previously operated from 1999 to 2011 and has been on a care and maintenance program since. There is significant infrastructure already in place, and the existing equipment will be refurbished where possible and supplemented with new and replacement equipment. The plant will process material at a nominal rate of 18.250 Mt/y for 16 years with an average head grade of 0.15% Cu and 0.37 g/t Au. The plant is designed to operate two shifts per day, 365 days per year with an overall plant availability of 92%. The process plant feed will be supplied by Kemess Main and the Kemess Underground deposit and will produce gold rich copper concentrate to be sold to smelters.

For information on the Kemess Project mineral reserves and mineral resources, see*“Mineral Reserves and Resources”* starting on page 16.

A combination of open pit and underground mining methods is proposed for the Kemess Project, as outlined in the Kemess Project Technical Report. The shallow, lower grade Kemess Main deposit, which is located directly above the Kemess Underground, is suited for open pit mining. A longhole open stoping method is proposed for the Kemess Underground deposit.

Open pit mining is scheduled to commence three years before underground development. The 16-year mine life includes 12 years of concurrent open pit and underground mining. The mining sequence facilitates both a phased pit expansion approach and the inclusion of high-grade underground material early in the mining schedule. Ore stockpiling requirements are expected to be minimal for the Kemess Project, and any stockpiling needed to meet operational requirements will be stored on the PAG facility.

Infrastructure

The 380-kilometre access road from MacKenzie to the Kemess Project is being maintained and used on a seasonal basis. The road will be used for truck transport of concentrates to the rail head at Mackenzie and delivery of materials and supplies to the Kemess Project.

The 16.5-kilometre forest service Cheni Mine Road is an all-season gravel road connecting the Kemess North site to the Kemess Main Road turn off. To accommodate non-loaded mining trucks, two bridges along the Cheni Mine Road require upgrading in addition to minor clearing and widening activities.

A 1.6-kilometre all-weather air strip is maintained for passenger aircraft and transport planes. A twin-engine Beech aircraft was routinely used to ferry personnel on and off site during the operation of the Kemess South mine.

Electrical power to the site is supplied by a 380 km, 230 kV transmission line to the mine site, including associated step-down transformers, backup diesel generators, and supporting infrastructure required to power the process plant and the Kemess South site. Centerra is the owner and operator of the transmission line and all related on-site electrical infrastructure.

In Mackenzie, Centerra retains a trans-shipment facility next to a rail spur, for shipment of the Mount Milligan Mine concentrates, which will also accommodate the Kemess Project shipments. Grinding media consumables are received by rail in MacKenzie for transshipment to the mines. The loadout facility at Mackenzie will need to be upgraded to handle increased volumes of concentrate.

The Kemess South mine site previously supported a 50,000 tpd open pit mining and milling operation including an administration building, assay and metallurgical labs, a truck shop, security facilities, and a personnel camp. Capital costs have been included for the development of a new camp to support operations for the life of mine. A new infrastructure pad is required at the Kemess North site to accommodate a truck shop for maintenance servicing and minor repairs, a fuel station, an emergency station, and offices. Other mine site infrastructure will comprise mine administration and maintenance facilities, offices, warehouse, a communications network, an energy management system, service mobile equipment, security facilities, and information technology installations.