DENISON MINES CORP.

Project Developments – Wheeler River

In February, Denison announced that it completed three drill holes during the fall of 2021 to follow up on the discovery of high-grade uranium mineralization in drill hole GWR-045 at Phoenix, which was located outside of the previously defined extent of the high-grade domain of Phoenix Zone A. All three follow-up holes returned intervals of high-grade uranium mineralization. The results were highlighted by drill hole GWR-049, which was expected to intersect a narrow high-grade interval according to then-current modeling, but instead returned 24.9% eU 3 O 8 over 4.2 metres.

In July, Denison announced that it received approval from the Province of Saskatchewan to prepare, construct, and operate the facilities required to carry out the ISR Feasibility Field Test (“FFT”) planned for the Phoenix deposit. The FFT was designed to use the existing commercial-scale ISR test pattern to perform a combined assessment of the Phoenix deposit’s hydraulic flow properties along with the leaching characteristics that had been assessed through the metallurgical core-leach testing program. The approval was granted by the Saskatchewan Minister of Environment and authorizes Denison to operate “pollutant control facilities”, which is typical for mining operations and allows for the management of material recovered from mineral extraction through to wastewater treatment, discharge, and storage (as applicable). The approval followed the completion of a process involving the review of and consultation on the Company’s permit application and supporting materials related to the FFT.

In August, the Company announced that it had received a Licence to Possess, Use, Store and Transfer a Nuclear Substance from the Canadian Nuclear Safety Commission (“CNSC”). With the receipt of this approval, the Company was fully permitted to operate the FFT facility and carry out the process of recovering a uranium bearing solution from the Phoenix ore body.

Also in August, Denison announced the substantial completion of extensive metallurgical test work to define the mechanical components for the planned Phoenix processing plant as part of the FS underway for Wheeler River. The test work confirmed the ability to produce a yellowcake product that meets industry standard ASTM C967-13 specifications.

In September, the Company reported the completion of the construction and wet commissioning of the lixiviant injection system for the FFT and commencement of the leaching phase of the FFT.

In October, the Company announced that it had successfully recovered uranium bearing solution from the ISR FFT at targeted rates and grades, indicating that the hydrogeological system at Phoenix was responding as expected with pH trends, flow characteristics, and uranium recovery meeting expectations. The preliminary results demonstrated the successful acidification of the test pattern and recovery of uranium using the ISR mining method. Given the highly successful results of the FFT, lixiviant injection ceased, and operations at the Phoenix FFT site transitioned from the leaching phase of the FFT to the neutralization phase.

Also in October, Denison announced a significant regulatory milestone for Wheeler River with the submission of the draft Environmental Impact Statement (“EIS”) to the Saskatchewan Ministry of Environment and the CNSC. The EIS submission outlines the Company’s assessment of the potential effects, including applicable mitigation measures, of the proposed ISR uranium mine and processing plant planned for Wheeler River, and reflects several years of baseline environmental data collection, technical assessments, plus extensive engagement and consultation with Indigenous and non-Indigenous interested parties.

In November, Denison announced the CNSC had completed its conformity review of the draft EIS submitted for the proposed ISR uranium mine and processing plant. The CNSC determined the draft EIS met the requirements for the advancement of the EA process, and the federal technical review of the EIS commenced.

In December, Denison announced highly successful results from long-term core leach metallurgical testing completed to further support the establishment of ISR production and recovery curves to be used in the Phoenix FS. The Company completed a long-term test of a representative intact core sample using specialized equipment to replicate in-situ leaching conditions of the Phoenix deposit. The results were highlighted by: (a) overall recovery of uranium in excess of 97%, demonstrating excellent recovery of uranium from intact high-grade core without the use of permeability enhancement; (b) average recovered solution uranium head grade of 18.3 g/L, exceeding the assumed 15 g/L uranium head grade being used in plant designs; (c) continuous intact core leach testing over a period of 377 days, with uranium recovery head grades consistently maintained above 5 g/L during the final stages of the production curve and then declining during the ramp-down stage; and (d) maximum recovered solution uranium head grade of 49.8 g/L achieved using similar lixiviant concentrations as to those used during the FFT.

And in December, Denison reported that the neutralization phase of the FFT had been successfully completed, advising that sampling of MWs around the FFT site confirmed the successful restoration of the leaching zone to environmentally acceptable pH conditions, as outlined in the applicable regulatory approvals for the FFT. The neutralization phase was initiated in mid-October, following the highly successful completion of the leaching phase of the FFT, and was designed to confirm certain environmental assessment assumptions and verify the efficiency and effectiveness of the neutralization process planned for ISR mining at Phoenix. The FFT was highlighted by the recovery of 14,400 pounds of U 3 O 8 dissolved in solutions generated during the leaching and neutralization phases of the test. The final phase of the FFT, involving the management of the recovered solution, was undertaken in 2023.

In January, the Company announced that the CNSC approved an amendment to the operating licence for the MLJV and MWJV operations, which allows for the expansion of the McClean Lake Tailings Management Facility (“TMF”) and accepts the associated revised Preliminary Decommissioning Plan (“PDP”) and cost estimate. See “Denison’s Operations – McClean Lake Mill & Cigar Lake Toll Milling – Mill Licence” for more information.

In March, Denison reported that multiple new high-grade intercepts of unconformity-hosted uranium mineralization were discovered in the final three drill holes completed during the winter 2022 exploration program at the Waterfound property, operated by Orano Canada. Denison holds an effective 24.68% ownership interest in Waterfound through its direct interest in the joint venture and its 50% ownership of JCU. The results were highlighted by drill hole WF-68, which returned a broad zone of uranium mineralization, including a peak interval of 5.91% eU 3 O 8 over 3.9 metres (0.05% eU 3 O 8 cut-off) with a sub-interval grading 25.30% eU 3 O 8 over 0.7 metres, located approximately 800 metres west, along the La Rocque Conductive Corridor, of the previously discovered high-grade mineralization (including 4.49% U 3 O 8 over 10.53 metres) at the Alligator Zone.

In April, Denison completed the sale of 40,000 pounds of U 3 O 8, representing the Company’s share of production from the SABRE test mining program completed at the MLJV in 2021. The uranium was sold at a price of $74.65 (US$59.25) per pound U 3 O 8.

In September, Denison announced that assays received from exploration drilling completed at McClean Lake during the winter of 2022 resulted in a significant expansion of the high-grade unconformity-hosted zone of uranium mineralization discovered in 2021 between the McClean South 8W and 8E pods. Ten drill holes completed during 2022 by Orano Canada returned notable uranium mineralization, including drill hole MCS-58, which returned 2.96% U 3 O 8 over 15.5 metres, including 24.49% U 3 O 8 over 1.5 metres, located approximately 54 metres to the southeast of drill hole MCS-34, which was completed in 2021 and returned a mineralized interval of 8.67% U 3 O 8 over 13.5 metres. Overall, the results from 2022 have successfully expanded the footprint of the mineralized zone to approximately 180 metres in strike length.

Also in September, Denison announced that uranium mineralization was encountered in three of the seven drill holes completed during the summer exploration program at Waterfound, highlighted by drill hole WF-74A, which intersected 4.75% eU 3 O 8 over 13.3 metres, including a sub-interval grading 25.23% eU 3 O 8 over 0.5 metres. The mineralized intersection from WF-74A represents the best mineralized hole drilled on the Waterfound property to date and highlights the potential for the discovery of additional high-grade uranium mineralization further along strike to the west of the Alligator Zone.

During 2022, the Company issued 11,042,862 Shares under the 2021 ATM Program. The Shares were issued at an average price of $1.83 per share for aggregate gross proceeds of $20,200,000. Denison also recognized issue costs of $599,000 related to the 2021 ATM Program Share issuances which includes $404,000 of commissions and $195,000 other costs associated with the maintenance of the 2021 ATM Program. See “Denison’s Securities – ATM Program Activity”.

In January, the Company amended and extended its Credit Facility to January 31, 2023.

Also in January, the Company executed a Repayment Schedule Agreement (the “Repayment Agreement”) with Uranium Industry a.s. (“UI”) pursuant to which the parties negotiated the repayment of the debt owing from UI to Denison with respect to the contingent proceeds of Denison’s sale to UI of its interest in the Gurvan Saihan Joint Venture in Mongolia in 2015 (the “Mongolia Transaction”). In accordance with the Repayment Agreement, the Company received aggregate installment payments in 2022 of US$4,800,000.

And in January, Denison announced the appointment of Ms. Laurie Sterritt to the Board of Directors and the appointment of Mr. Kevin Himbeault as the Company’s Vice President Plant Operations & Regulatory Affairs.

In February, Mr. Jun Gon Kim resigned from the Board. Mr. Yun Chang Jeong joined the Board in early March, filling the vacancy created by Mr. Kim’s resignation.

In April, Denison released its inaugural ESG Report regarding the Company’s environmental, social and governance initiatives and demonstrating its ongoing commitment to sustainability and transparency. Denison’s ESG Reports focus on key ESG topics including the Company’s objective to maintain excellence in corporate governance practices, “best in class” engagement with communities potentially impacted by its activities, diversity in the Company’s workforce, and robust assessments of the environment and biodiversity in the regions within which it operates.

And in April, in connection with the updated PDP and related decrease in the financial assurances required for the MLJV and MWJV reclamation obligation, the Company entered into a further amendment with respect to the Credit Facility pursuant to which the pledged amount of cash required under the Credit Facility was decreased and the additional cash collateral was released.

In May, at Denison’s Annual General Meeting of Shareholders, Mr. Bob Dengler did not stand for re-election to the Board.

In June, Denison and Kineepik Métis Local #9 (“KML”) entered into a Participation and Funding Agreement (the “KML PFA”), which expresses Denison’s and KML’s mutual commitment to the co-development of an agreement supporting the advancement of the Phoenix ISR project. The KML PFA builds on an existing letter agreement between Denison and KML with respect to the support of KML’s contributions to, and participation in, the Federal and Provincial EA process. The parties also entered into an Exploration Agreement (the “KML Exploration Agreement”) in respect of Denison’s exploration and evaluation activities within KML’s land and occupancy area. These agreements reflect Denison’s commitment to the principles set out in the Company’s IPP and advancing reconciliation through taking action.

In October, Denison announced that it entered into an exploration agreement (the “YNLRO Exploration Agreement”) with the Ya’thi Néné Lands and Resources Office (“YNLRO”), Hatchet Lake Denesułiné First Nation, Black Lake Denesułiné First Nation, Fond du Lac Denesułiné First Nation (collectively, the “Athabasca Nations”) and the Northern Hamlet of Stony Rapids, the Northern Settlement of Uranium City, the Northern Settlement of Wollaston Lake and the Northern Settlement of Camsell Portage (collectively, the “Athabasca Communities”) in respect of Denison’s exploration and evaluation activities within the traditional territory of the Athabasca Nations (the “Nuhenéné”). The YNLRO Exploration Agreement expresses the parties’ intention to build a long-term relationship between Denison and the YNLRO, Athabasca Nations, and Athabasca Communities. Denison wishes to conduct and advance its exploration activities in a sustainable manner that respects the Athabasca Nations’ Indigenous rights, advances reconciliation with Indigenous peoples, and provides economic opportunities and other benefits to the Athabasca Communities in an authentic, cooperative and respectful way.

In December, the Company amended the terms of the Credit Facility to extend the maturity date to January 31, 2024, and to increase the credit available under the facility to cover additional standby letters of credit with respect to environmental obligations associated with the FFT activities at Wheeler River.

And in December, Mr. David Bronkhorst retired from his position as Vice President Operations of Denison, remaining with the Company in a technical advisory role. Concurrently therewith, Mr. Himbeault became Vice President Operations & Regulatory Affairs.

2023…