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LocationWestern AustraliaCameco's share100%Mine typeOpen pitEstimated resources128.1 million lbs (measured and indicated)Average ore grade0.15% U3O8ProductUranium concentratesDiscovered1972Development ProgressWe believe that we have some of the best undeveloped uranium projects in the world. However, our current focus is on producing from our tier-one uranium assets at a pace aligned with our contract portfolio and market opportunities. No work is planned at Yeelirrie in 2026.Environmental AssessmentsA number of studies have been completed to evaluate the potential effects during the construction, operation, and decommissioning of the Yeelirrie project.Learn more at camecoaustralia.com

US ISR OperationsAs a result of our 2016 curtailment decision, commercial production has ceased. As production is suspended, we expect ongoing cash and non-cash care and maintenance costs to range between US$14 million and US$15 million for 2026.See full Quarterly ReportEnvironment & SafetyWorker safety, environmental monitoring and proper decommissioning after project completion are of the utmost importance to Cameco.See moreReserves & ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.See more

2026 Q2 UpdateProductionMcArthur River ProductionCameco's Share (million lb)Three months ended June 30 Six months ended June 30  20262025Change20262025Change2026 Plan  2.31.828%5.85.114%10.0 to 11.5   In the second quarter of 2026, total packaged production from McArthur River and Key Lake was 3.3 million pounds (2.3 million pounds our share) compared to 2.6 million pounds (1.8 million pounds our share) in the second quarter of 2025. In the first six months of the year, total packaged production from McArthur River and Key Lake was 8.3 million pounds (5.8 million pounds our share) compared to 7.3 million pounds (5.1 million pounds our share) in the first six months of 2025. Production has been higher in 2026 due to differences in the mine planIn May, flooding in northern Saskatchewan affected the primary transportation route used to supply the McArthur River and Key Lake operations. Although the sites themselves were not directly impacted, the delivery of critical operating materials and reagents was interrupted, resulting in a temporary suspension of production at Key Lake and reduced mining activity at McArthur River for approximately two weeks. We continue to expect production between 14.0 million to 16.5 million pounds of U3O8 (10.0 million to 11.5 million pounds our share) in 2026. Maintenance ShutdownsThe annual maintenance outage at the Key Lake mill is expected to begin in the third quarter. Due to the nature of the work being carried out, the planned shutdown period is expected to be longer than in previous years and there is a risk that production may be impacted if there are restart challenges or delays in commissioning new equipment.There is no planned shutdown of the McArthur River mine in 2026. Labour RelationsA new collective agreement with the United Steelworkers Local 8914 was reached in April 2026, for a 3-year term, expiring in December 2028.See full Quarterly ReportEnvironment & SafetyWorker safety, environmental monitoring and proper decommissioning, after mining is completed, are of the utmost importance to Cameco.See moreReserves & ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.See more

Measured and Indicated As of December 31, 2025(100% basis)(tonnes in thousands; pounds in millions; totals may not add up due to rounding) MeasuredIndicatedTotal Measured and IndicatedPropertyTonnesGrade%U3O8Content(lbs U3O8)TonnesGrade%U3O8Content(lbs U3O8)Content(lbs U3O8)Cameco’s Share(lbs U3O8)Cigar Lake82.35.09.1153.85.0717.226.314.3Kintyre   3,897.70.6253.553.553.5McArthur River72.02.283.662.62.223.16.74.7Millennium   1,442.62.3975.975.953.0Rabbit Lake   1,836.50.9538.638.638.6Tamarack   183.84.4217.917.910.3Yeelirrie27,172.90.1695.912,178.30.1232.2128.1128.1Crow Butte1,558.10.196.6939.30.357.213.813.8Gas Hills-Peach687.20.111.73,626.10.1511.613.313.3Inkai75,923.10.0358.263,488.40.0234.592.737.1North Butte-Brown Ranch604.20.081.11,438.40.092.83.93.9Ruby Ranch   2,215.30.084.14.14.1Shirley Basin89.20.160.31,638.20.114.14.44.4Smith Ranch-Highland3,703.50.107.914,372.30.0517.024.924.9Total109,892.5-184.4107,462.3-319.7504.0404.0Note that mineral resources:do not include amounts that have been identified as mineral reservesdo not have a demonstrated economic viabilitytotals may not add due to roundingInferredAs of December 31, 2025(100% basis)(tonnes in thousands; pounds in millions; totals may not add up due to rounding)PropertyTonnesGrade%U3O8Content(lbs U3O8)Cameco’s Share(lbs U3O8)Cigar Lake163.45.5520.010.9Fox Lake386.77.9968.153.3Kintyre517.10.536.06.0McArthur River36.40.532.41.7Millennium412.43.1929.020.2Rabbit Lake2,460.90.6233.733.7Tamarack45.61.021.00.6Crow Butte531.40.161.81.8Gas Hills-Peach3,307.50.086.06.0Inkai33,742.20.0323.38.9North Butte-Brown Ranch294.50.070.40.4Ruby Ranch56.20.140.20.2Shirley Basin508.00.101.11.1Smith Ranch-Highland6,861.00.057.77.7Total49,323.5-201.3153.2Note that mineral resources:do not include amounts that have been identified as mineral reservesdo not have a demonstrated economic viabilitytotals may not add due to roundingMineral Reserves and ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.We have interests in a number of uranium properties. The tables in this section show the estimates of the proven and probable mineral reserves, and measured, indicated, and inferred mineral resources at those properties. However, only three of the properties listed in those tables are material uranium properties for us: McArthur River/Key Lake, Cigar Lake and Inkai. Mineral reserves and resources are all reported as of December 31, 2025.We estimate and disclose mineral reserves and resources in five categories, using the definition standards adopted by the Canadian Institute of Mining, Metallurgy and Petroleum Council, and in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101), developed by the Canadian Securities Administrators.  About mineral resourcesMineral resources do not have to demonstrate economic viability but have reasonable prospects for eventual economic extraction. They fall into three categories: measured, indicated and inferred. Our reported mineral resources are exclusive of mineral reserves.measured and indicated mineral resources can be estimated with sufficient confidence to allow the appropriate application of technical, economic, marketing, legal, and sustainability factors to support evaluation of the economic viability of the depositmeasured resources: we can confirm both geological and grade continuity to support detailed mine planningindicated resources: we can reasonably assume geological and grade continuity to support mine planninginferred mineral resources are estimated using limited geological evidence and sampling information. We do not have enough confidence to evaluate their economic viability in a meaningful way. You should not assume that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource, but it is reasonably expected that the majority of inferred mineral resources could be upgraded to indicated mineral resources with continued exploration.Our share of uranium in the following mineral resource tables is based on our respective ownership interests. Reported mineral resources have not demonstrated economic viability.About mineral reservesMineral reserves are the economically mineable part of measured and/or indicated mineral resources demonstrated by at least a preliminary feasibility study. The reference point at which mineral reserves are defined is the point where the ore is delivered to the processing plant, except for ISR operations where the reference point is where the mineralization occurs under the existing or planned wellfield patterns. Mineral reserves fall into two categories:proven reserves: the economically mineable part of a measured resource for which at least a preliminary feasibility study demonstrates that, at the time of reporting, economic extraction could be reasonably justified with a high degree of confidenceprobable reserves: the economically mineable part of a measured and/or indicated resource for which at least a preliminary feasibility study demonstrates that, at the time of reporting, economic extraction could be reasonably justified with a degree of confidence lower than that applying to proven reserves For properties where we are the operator, we use current geological models, an average uranium price of $63 (US) per pound U3O8, and current or projected operating costs and mine plans to report our mineral reserves, allowing for dilution and mining losses. We apply our standard data verification process for every estimate. For properties in which we have an interest but are not the operator, we will take reasonable steps to ensure that the reserve and resource estimates that we report are reliable.Our share of uranium in the mineral reserves table below is based on our respective ownership interests.Changes this year Our share of proven and probable mineral reserves decreased from 457 million pounds U3O8 at the end of 2024 to 433 million pounds at the end of 2025. The change was primarily the result of production at Cigar Lake, Inkai and McArthur River, which removed 25 million pounds of proven and probable reserves from our mineral inventory slightly offset by other adjustments based on the mineral reserve estimate updates at Cigar Lake, McArthur River and Inkai.Our share of measured and indicated mineral resources decreased from 408 million pounds U3O8 at the end of 2024 to 404 million pounds at the end of 2025. Our share of inferred mineral resources decreased from 153 million pounds U3O8 to 152 million pounds U3O8. Qualified personsThe technical and scientific information discussed on this page for our material properties (McArthur River/Key Lake, Cigar Lake and Inkai) was approved by the following individuals who are qualified persons for the purposes of NI 43-101:McArthur River/Key LakeGreg Murdock, general manager, McArthur River, CamecoDaley McIntyre, general manager, Key Lake, CamecoAlain D. Renaud, principal resource geologist, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoCigar LakeKirk Lamont, general manager, /Cigar Lake, CamecoScott Bishop, director, technical services, CamecoAlain D. Renaud, principal resource geologist, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoInkaiAlain D. Renaud, principal resource geologist, technical services, CamecoScott Bishop, director, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoSergey Ivanov, deputy director general, technical services, Cameco Kazakhstan LLPImportant information about mineral reserve and resource estimatesAlthough we have carefully prepared and verified the mineral reserve and resource figures in this document, the figures are estimates, based in part on forward-looking information.Estimates are based on knowledge, mining experience, analysis of drilling results, the quality of available data and management’s best judgment. They are, however, imprecise by nature, may change over time, and include many variables and assumptions, including:geological interpretationextraction planscommodity prices and currency exchange ratesrecovery ratesoperating and capital costsThere is no assurance that the indicated levels of uranium will be produced, and we may have to re-estimate our mineral reserves based on actual production experience. Changes in the price of uranium, production costs or recovery rates could make it unprofitable for us to operate or develop a particular site or sites for a period of time. See page 2 of our 2025 Q4 MD&A for information about forward-looking information.Please see our mineral reserves and resources section of our most recent annual information form for the specific assumptions, parameters and methods used for McArthur River, Inkai and Cigar Lake mineral reserve and resource estimates. Important information for US investorsWe present information about mineralization, mineral reserves and resources as required by National Instrument 43-101 – Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators (NI 43-101), in accordance with applicable Canadian securities laws. As a foreign private issuer filing reports with the US Securities and Exchange Commission (SEC) under the Multijurisdictional Disclosure System, we are not required to comply with the SEC’s disclosure requirements relating to mining properties. Investors in the United States should be aware that the disclosure requirements of NI 43-101 are different from those under applicable SEC rules, and the information that we present concerning mineralization, mineral reserves and resources may not be comparable to information made public by companies that comply with the SEC’s reporting and disclosure requirements for mining companies.

Rabbit Lake remains in a safe state of care and maintenance following the suspension of production in 2016. We continue to evaluate opportunities to minimize care and maintenance costs while maintaining critical infrastructure and processes. We expect care and maintenance costs to range between $44 million and $47 million for 2026.See full Quarterly ReportEnvironment & SafetyWorker safety, environmental monitoring and proper decommissioning after project completion are of the utmost importance to Cameco.See moreReserves & ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.See more

SafetyThe Inkai operation has an excellent safety record. The operation has a management system to identify, document and address risks and engage all workers and managers in development of a strong safety culture. The safety management system is certified to the international OHSAS:18001 standard and is focused on driving continual improvement in safety performance of employees and contractors.Radiation ProtectionRadiation risks are effectively managed at Inkai through a formal radiation protection program and dedicated personnel who ensure that doses to workers are as low as reasonably achievable. The program ensures that radiation protection is considered in the physical design of all facilities and operating procedures. It also provides for systematic monitoring of radiation in work areas and tracking the exposures of individual workers using a combination of monitoring devices and health testing. Radiation exposures at Inkai are far below the regulated limits.Environmental ProtectionEnvironmental protection at Inkai is managed through an ISO 14001-certified environmental management system. The system provides for systematic identification and mitigation of environmental risks and reduction and effective management of waste. Inkai uses the in situ recovery (ISR) mining method which produces no tailings or waste rock and involves minimal surface disturbance. Uranium is extracted from underground by pumping a mild acid solution into the ore zone. The uranium is freed from a sandstone formation and pumped to the surface for processing.Environmental MonitoringMonitor wells are installed around the ore zones to allow testing of groundwater quality around the ore zones.Waste ManagementThe situ recovery (ISR) mining method employed at Inkai produces no tailings or waste rock. Water used in the process is recycled. Plastic, cardboard, scrap metal and other waste materials are sent for recycling to external companies.DecommissioningDetailed plans are being developed to provide for decommissioning of the Inkai mine. Once operations are complete in a wellfield, the brackish groundwater in the deep sandstone aquifer being mined recovers by natural attenuation. All piping and other infrastructure is removed and surface lands are restored to their original state.Environmental AssessmentAll new mining developments and significant changes to existing operations are subject to environmental review and licensing by Kazakh regulatory authorities.Regulatory OversightThe Inkai operation is overseen by a number of Kazakh regulatory authorities, including the Atomic Energy Committee, the Ministry of Environmental Protection, the Ministry of Emergency Situations and the Ministry of Labour and Social Protection.

Our relationships with our workforce, Indigenous Peoples, and local communities are fundamental to our success. We aim to build a workforce that is dedicated to continuous improvement and shares our values.The following are highlights of selected social topics discussed in our 2025 Sustainability Report. Please see the report for more information or Our Performance for all indicator results.

Since 1990, Blind River has received Cameco's top award for safety performance, the Mary-Jean Mitchell Green Award, more times than any other Cameco facility.SafetyWe manage the safety of our workers through programs, systems, and standards, with our Safety, Health, Environment and Quality (SHEQ) Policy providing overarching guidance. There are many aspects of the management system that contribute to a safe work environment, a few examples include:Risk assessments help identify issues and determine the appropriate controls; the corrective action process verifies that incidents and near misses are reported, tracked, investigated and shared with colleagues; and emergency preparedness and planning prepare us to respond to serious incidents.We have developed 12 corporate safety standards to help protect our workers from our most common hazards. Some standards guide our general safety practices, such as our job hazard analysis and our job task observation, and other standards deal with specific hazardous situations (similar to other companies’ life saving rules): such as fall protection, confined space entry, rigging and hoisting, and control of hazardous energy (also referred to as lockout/tagout).Routine audits are conducted to monitor compliance with regulations and our own requirements. These and other aspects of the management system are routinely examined to verify that they continue to be effective at keeping our workers safe.Radiation ProtectionRadiation risks are effectively managed at Blind River through a formal radiation protection program and dedicated personnel who ensure that workers are safe. The program ensures that radiation protection is considered in the physical design of all facilities and operating procedures. It also provides for systematic monitoring of radiation in work areas and tracking the exposures of individual workers using a combination of monitoring devices and health testing. Radiation exposures at Blind River are far below regulatory limits.Environmental ProtectionAt Cameco, protection of the environment is one of our highest corporate priorities during all stages of our activities, from exploration through development, operations, decommissioning, and reclamation.We monitor our performance by tracking corporate and site-specific key performance indicators, conducting environmental monitoring programs, and regularly auditing our adherence to the requirements of these programs We use the information from all of our programs to help us to identify opportunities to improve.Environmental management systemWe have a ISO 14001-certified environmental management system used across our operating sites, which is supported by a corporate Environmental Management Program that outlines the operating requirements sites must meet. Our environmental management system encourages and promotes continuous adaptation of our practices based on new information and technologies.Environmental risk assessmentsWe complete environmental risk assessments to systematically identify, quantify, and to characterize the potential risks to the environment, workers, and the public. We use our environmental risk assessments to inform our decisions and actions. Additionally, we complete an iterative process, where required, to verify that our proposed measures to protect the environment and the public are effective. We review or update the assessments every five years, incorporating results from our environmental monitoring programs and other scientific advances.Corrective action processWe have a corrective action process in place to systematically investigate and address the causes of non-conformance to regulatory requirements or internal standards. The process includes classifying the non-conformance, assigning the appropriate level of investigation (dependent on incident significance), and tracking the recommended corrective actions to prevent and mitigate similar occurrences.AuditsTo support our culture of continuous improvement, our processes and operations undergo regular audits, including:Our environmental management system is audited by a third-party every three years as a requirement to maintain our ISO 14001 certification.Our SHEQ team conducts an internal audit of our SHEQ programs on a three-year cycle. The total audit scope is split in half and executed on a rotating basis. This means that all our sites undergo at least two audits to cover all aspects of our SHEQ programs within every three-year period. The audit follows the ISO 19001 process and encompasses our environmental and safety programs.We also maintain and implement an internal audit program at our corporate office. Results and recommendations from this systematic and documented process are presented to senior management, who are responsible for implementing them and correcting any deficiencies. The internal audit group reports to the audit and finance committee of the board.Environmental Incidents and Other Events​Environmental incidents and other events are reported to regulatory agencies as required by federal and provincial regulations. This includes releases to the environment reportable to Ontario Ministry of Environment's Spills Action Centre.If you have questions about any of the items posted here, please contact us.Latest incident or event:Posting DateAugust 11, 2026Incident DateAugust 7, 2026IncidentNon-Occupational Emergency TransportDetailsA non-Cameco employee experiencing a non-occupational medical illness was assessed by a site first aid attendant and transported by ambulance to a local health care facility for further evaluation.Corrective ActionN/ACameco Environmental Effect RatingN/APast reportingPosting DateAugust 11, 2026Incident DateAugust 7, 2026IncidentNon-Occupational Emergency TransportDetailsA non-Cameco employee experiencing a non-occupational medical illness was assessed by a site first aid attendant and transported by ambulance to a local health care facility for further evaluation.Corrective ActionN/ACameco Environmental Effect RatingN/APosting DateAugust 6, 2026Incident DateJuly 31, 2026Incident Reportable Discharge DetailsFollowing routine monitoring, results revealed that effluent discharge in July from stormwater collection exceeded the Ministry of Environment, Conservation and Parks discharge limit for total suspended solids as a result of the sitewide wildfire ash deposits. It should be noted that the Refinery only operated for three days in late July. The regulatory limit is 15.0 mg/L, but the July monthly average was 17.6mg/L.There was no health or safety risk posed to the public, workers, or the environment.Corrective ActionThe Ministry of the Environment, Conservation and Parks and the Canadian Nuclear Safety Commission have been notified.Conservation and Parks and the Canadian Nuclear Safety Commission have been notified.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateApril 14, 2026Incident DateApril 13, 2026IncidentNon-Reportable SpillDetailsDuring the spring thaw, ground movement caused several drums containing uranium ore concentrates to topple. This resulted in a small release of uranium ore concentrate onto the paved surface.There was no risk of uranium escaping the facility boundary, and no risk to the health or safety of the public. The volume of material released was well below the reportable threshold of 200 kg.Corrective ActionDamaged drums and pallets were contained, and residual material was recovered. The area was radiation monitored until cleanup was completed. Cameco informed the Canadian Nuclear Safety Commission.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateFebruary 18, 2026  Incident DateFebruary 9, 2026IncidentTransportation IncidentDetailsUpon opening a sea container at the Blind River Refinery, an employee identified a small amount of contamination on a drum and a very small amount of loose uranium on the plastic liner. There was no health or safety risk posed to the public or the environment.  Corrective ActionThe contaminated drum was cleaned, and the contaminated liner was disposed of in accordance with applicable regulatory requirements. The sea container was monitored for contamination and met release criteria in accordance with applicable regulatory requirements. Cameco notified the consignor and the Canadian Nuclear Safety Commission. Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateJanuary 12, 2026Incident DateDecember 15, 2025IncidentNon-Reportable SpillDetailsA lift truck carrying eight drums of uranium ore concentrate was involved in a single vehicle incident in the yard of the Blind River Refinery. The lift truck contacted an unmarked curb, covered by snow causing the truck to shift. Six of the eight drums were affected resulting in the release of approximately 150 kilograms of uranium ore concentrate onto the paved surface. There was no health or safety risk posed to the driver, public or the environment.Corrective ActionDamaged drums and pallets were contained, and residual material was recovered. The area was radiation monitored until cleanup was completed. Cameco notified the Canadian Nuclear Safety Commission.Cameco Environmental Effect Ratingnegligible impact 2Posting DateOctober. 21, 2025Incident DateSeptember 18, 2025IncidentERT ActivationDetailsA pull station was activated at the Blind River Refinery when a small fire was observed on a piece of equipment in the plant. The fire was extinguished using a nearby extinguisher. The emergency response team was activated. There was no health or safety risk posed to the workers or environment.Corrective ActionThe small fire was extinguished and cleaned up. The Canadian Nuclear Safety Commission was notified.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateMarch 10, 2025Incident DateMarch 6, 2025IncidentTransportation Incident DetailsA tractor trailer carrying three full UO3 tote bins was involved in a minor vehicle incident while travelling south on Highway 12. A passenger vehicle pulled out in front of the tractor trailer causing the driver to swerve into the far lane attempting to avoid a collision but in doing so struck another vehicle with its trailer.There was no damage to the tractor trailer, nor the tote bins so the vehicle continued onto its intended destination.There was no health or safety risk posed to the public or the environment.Corrective ActionThe police were called and attended the scene. As there was no damage to the tractor trailer it continued to its intended destination.Cameco notified the Canadian Nuclear Safety Commission transport section.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateFebruary 28, 2025 Incident DateFebruary 27, 2025 IncidentTransportation Incident DetailsA tractor trailer carrying three full UO3 tote bins was involved in a minor incident when stopped at a red traffic light in Blind River eastbound on Highway 17. A passenger vehicle, unable to stop due to slippery road conditions, rear-ended the tractor trailer. There was no damage to the tractor trailer or the tote bins, so the vehicle was able to safely continue onto its intended destination. There was no health or safety risk posed to the public or the environment. Corrective ActionThe police were called and representatives from Cameco and the trucking company attended the scene. As there was no damage to the tractor trailer continued to its intended destination. Cameco notified the Canadian Nuclear Safety Commission transport section. Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateJanuary 28, 2025Incident DateJanuary 23, 2025IncidentTransport Occurrence (Minor Vehicle Incident)DetailsA tractor trailer carrying a sea container of uranium ore concentrate was involved in a minor incident on Highway 401 east bound near Brockville, Ontario. A passenger vehicle was merging onto Highway 401 when its driver lost control, crossing all lanes and ending up in front of the truck.There was no damage to the trailer nor the sea container, and only minor damage to the front of the truck. The truck was still roadworthy and continued to its intended destination, Cameco’s Blind River Refinery.                             There was no health or safety risk posed to the public or the environment.Corrective ActionThe passenger vehicle was towed from the scene. There was no damage to the trailer or sea container, and only minor damage to the front of the truck. The truck continued to its intended destination. Cameco notified the Canadian Nuclear Safety Commission transport section.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateNovember 29, 2024Incident DateNovember 28, 2024IncidentERT ActivationDetailsOn November 28, a pull station was activated at the Blind River Refinery when a small fire was observed inside of a 5-gallon plastic pail in the plant. The fire was extinguished using a nearby fire extinguisher.Due to the speedy response and action of the emergency response team there was no health or safety risk posed to the workers or the environment.Corrective ActionThe fire was extinguished and cleaned up. The Canadian Nuclear Safety Commission was notified.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateJuly 30, 2024Incident DateJuly 1, 2024IncidentReportable Leak & DischargeDetailsOn June 26, 2024, when the glycol heating systems were drained for maintenance, a mechanical failure occurred. It was observed that the drain valve on number three coil was leaking glycol. A pipe cap was immediately installed to stop the leak. It was assumed the leak had been minimal and there was minimal glycol in the system since the coil had been isolated and drained in 2023 when it had failed.During a maintenance inspection, it was determined that glycol had passed through the sewage plant and was released to Lake Huron on July 1, 2024. A lab investigation estimates 70L of glycol had spilled.  There was no health or safety risk posed to the public, workers, or the environment by this release.Corrective ActionAn investigation is currently underway by Cameco to prevent future occurrences.The Canadian Nuclear Safety Commission, Town of Blind River and the Ministry of Environment, and Conservation and Parks have been notified.Cameco Environmental Effect Ratingno measurable impact to the environment1Posting DateMay 3, 2024Incident DateMay 2, 2024IncidentReportable SpillDetailsOn April 18, a sink hole was observed near two groundwater supply wells for the Blind River Refinery, close to the Mississaugi River. This sinkhole was located adjacent to the golf course, situated west of the parking lot, which is part of the Town property leased from Cameco. As a precautionary measure, we promptly cordoned off the affected area and initiated the process of determining next steps to have the underground well water supply line repaired. Cameco has been closely monitoring the sinkhole and noted no significant changes. On May 2, it was observed that there is now additional groundwater flow from the well line, carrying sediment and overflowing into the river.There was no health or safety risk posed to the public, workers, or the environment by the release of groundwater that had not been used by the refinery.Corrective ActionCameco is working to rectify the situation and has contacted a contractor to install a silt curtain and are in the process of securing hydrovac services. Additionally, Cameco is actively pursuing a separate contractor to repair the well supply line.The Canadian Nuclear Safety Commission, Town of Blind River and the Ministry of Environment, Conservation and Parks have been notified.Cameco Environmental Effect Ratingno measurable impact to the environment1Cameco Environmental Effect RatingLevel 1 - no measurable impact to the environmentLevel 2 - negligible impactLevel 3 - short-term, seasonal impactLevel 4 - mortality of some species, but not affecting ecosystem functionLevel 5 - impairment of ecosystem functionN/A - not applicableNotes1 Includes all releases to the environment reportable to Ontario Ministry of Environment's Spills Action Centre and other significant events.Waste ManagementSolid wastes contaminated by uranium are reprocessed, recycled and re-used to the extent possible. Waste materials that cannot be reprocessed, recycled or re-used are safely stored on site until appropriate disposal options are available.DecommissioningDetailed plans and financial guarantees are in place to restore the Blind River site to public use once the facility reaches the end of its productive life.Environmental AssessmentAll new significant changes to existing operations are subject to environmental assessments to identify potential effects on the environment.Regulatory OversightThe Blind River refinment facility is licensed and regulated by the Canadian Nuclear Safety Commission (CNSC). The operation is also subject to other federal and provincial regulations for the protection of people and the environment, including by Environment Canada and Ontario’s Ministry of the Environment. Federal and provincial regulators conduct regular site inspections and audits to verify that people and the environment are protected. Sustainability at CamecoWhen measuring the sustainability and ethical impact of a company, environmental, social and governance (ESG) are key factors considered by the public and investors. Sustainability and ESG matters have been an important focus at Cameco for many years and we have a strong performance record.Learn More

LocationSaskatchewan, CanadaCameco's share69.9%Mine typeUndergroundEstimated resources (Cameco's share)53.0 million lbs (indicated), average grade U3O8: 2.39%20.2 million lbs (inferred), average grade U3O8: 3.19%ProductUranium concentratesDiscovered2000Other possible featuresOff-site processingEmployment: about 150 at full productionEstimated life of mine: 10 yearsDevelopment ProgressWe believe that we have some of the best undeveloped uranium projects in the world. However, our current focus is on producing from our tier-one uranium assets at a pace aligned with our contract portfolio and market opportunities. No work is planned at Millennium in 2026.Environmental AssessmentA number of studies have been completed to evaluate the potential effects during the construction, operation, and decommissioning of the Millennium project.See more

US ISR OperationsAs a result of our 2016 curtailment decision, commercial production has ceased. As production is suspended, we expect ongoing cash and non-cash care and maintenance costs to range between US$14 million and US$15 million for 2026.See full Quarterly ReportEnvironment & SafetyWorker safety, environmental monitoring and proper decommissioning after project completion are of the utmost importance to Cameco.See moreReserves & ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.See more

2026 Q2 UpdateProductionProduction on a 100% basis was 2.8 million pounds for the quarter and 5.3 million pounds for the first six months of the year, compared to 2.3 million pounds and 3.5 million pounds respectively in the same period last year. JV Inkai is targeting 2026 production of 10.4 million pounds (100% basis) of which our purchase allocation is expected to be 4.2 million pounds U3O8. In the first half of the year, we purchased 0.8 million pounds of U3O8. The achievement of JV Inkai’s 2026 production target requires it to successfully manage several ongoing risks, including the availability of sulfuric acid, other procurement and supply chain issues, transportation challenges, construction delays and inflationary pressures on its production costs.Due to equity accounting, our share of production is shown as a purchase at a 5% discount to the spot price and included in inventory at this value at the time of delivery. Our share of the profits earned by JV Inkai on the sale of its production to the joint venture partners is included in “share of earnings from equity-accounted investee” on our consolidated statement of earnings. Excess cash, net of working capital requirements, is distributed to the partners as dividends once declared. The geopolitical situation continues to cause transportation risks in the region. We could continue to experience delays in our expected Inkai deliveries. To mitigate this risk, we have inventory, long-term purchase agreements and loan arrangements in place we can utilize. Depending on when we receive shipments of our share of Inkai’s production, our share of earnings from this equity-accounted investee and the timing of the receipt of our share of dividends from the joint venture may be impacted.Delivery ScheduleThe geopolitical situation continues to cause transportation risks in the region. We could continue to experience delays in our expected Inkai deliveries. To mitigate this risk, we have inventory, long-term purchase agreements and loan arrangements in place we can draw on. Depending on when we receive shipments of our share of Inkai’s production, our share of earnings from this equity-accounted investee and the timing of the receipt of our share of dividends from the joint venture may be impacted.See full Quarterly ReportEnvironment & SafetyWorker safety, environmental monitoring and proper decommissioning after project completion are of the utmost importance to Cameco.See moreReserves & ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.See more