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Corporate History

Denison was formed by articles of amalgamation as International Uranium Corporation ("IUC"), effective May 9, 1997 pursuant to the Business Corporations Act (Ontario) (the "OBCA"). On December 1, 2006, IUC combined its business and operations with Denison Mines Inc. (“DMI”), by way of arrangement under the OBCA (the "IUC Arrangement"). Pursuant to the IUC Arrangement, all of the issued and outstanding shares of DMI were acquired in exchange for IUC's shares. Effective December 1, 2006, IUC's articles were amended to change its name to "Denison Mines Corp."

Prior to July 2012, Denison was engaged in the exploration, development, mining, and milling of uranium and vanadium, with projects in the United States, Canada, Zambia and Mongolia. At the time, Denison's principal assets included 100% ownership of the White Mesa Mill in Utah and 22.5% ownership of the McClean Lake uranium mill in Saskatchewan.

On June 29, 2012, Denison sold its shares in certain subsidiaries, which owned all of the Company's mining assets and operations located in the United States ("U.S. Mining Division"). The sale was carried out by way of a plan of arrangement between Denison and Energy Fuels Inc. ("EFR"). After completing the various steps in the plan of arrangement, Denison shareholders retained their interest in Denison and received 1.106 common shares of EFR for each Share held in Denison. By completing the transaction with EFR, Denison transformed its business to focus on its uranium exploration and development projects in Saskatchewan, Zambia and Mongolia.

In 2013, through its acquisitions of JNR Resources Inc. ("JNR"), Fission Energy Corp. ("Fission") and Rockgate Capital Corp. ("Rockgate"), and in 2014, through its acquisition of International Enexco Limited ("IEC"), Denison increased its project portfolio in Canada, primarily in the Athabasca Basin, and expanded its position in Africa by acquiring interests in uranium exploration properties in Namibia and Mali.

Throughout 2015 and 2016, Denison worked to further achieve its objective of focusing on its core activities in the Athabasca Basin. In November 2015, Denison completed the sale of its interest in the Gurvan Saihan joint venture in Mongolia to Uranium Industry a.s. pursuant to an amended and restated share purchase agreement entered into on November 25, 2015.

In June 2016, GoviEx Uranium Inc. ("GoviEx") and Denison completed a transaction to combine their respective African uranium mineral interests, in which GoviEx acquired all of Denison's African uranium mineral interests in Zambia, Mali and Namibia through the acquisition from Denison of Rockgate. In exchange for Rockgate, Denison received a total of 56,050,450 common shares of GoviEx and 22,420,180 GoviEx common share purchase warrants.

In 2017, Denison executed an agreement with the partners of the Wheeler River Joint Venture ("WRJV"), pursuant to which Denison's ownership of the Wheeler River project increased to approximately 66% by October 2018. In 2018, Denison subsequently entered into an agreement with Cameco Corporation, pursuant to which Denison acquired Cameco's approximate 24% in the project in exchange for the issuance of 24,615,000 common shares of Denison. As a result, effective October 26, 2018, the WRJV is a joint venture between Denison as operator (now 90% interest) and JCU (Canada) Exploration Limited ("JCU") (10% interest).


In September 2018, Denison entered into an agreement with Cameco Corporation pursuant to which Denison would increase its ownership interest in the Wheeler River project to 90% through the acquisition of 100% of Cameco’s minority interest in the Wheeler River Joint Venture (“WRJV”) (subject to certain rights of first refusal in favour of JCU (Canada) Exploration Limited (“JCU”), pursuant to the WRJV joint venture agreement) in exchange for the issuance to Cameco of 24,615,000 Shares of Denison. JCU waived its rights under the WRJV joint venture agreement to acquire any of Cameco’s interest, and Denison’s acquisition of Cameco’s interest was completed effective October 26, 2018.

Also in September 2018, Denison announced the results of the Pre-Feasibility Study (“PFS”) for the Wheeler River project. The PFS was completed in accordance with NI 43-101 and is highlighted by the selection of the in-situ recovery (“ISR”) mining method for the development of the high-grade Phoenix deposit with an estimated average operating cost of $4.33 (US$3.33) per pound U3O8. The PFS  considers the potential economic merit of co-developing the Phoenix and Gryphon deposits. The ISR mining operation planned for Phoenix, would see associated processing to a finished product occurring at a plant to be built on site at Wheeler River. The Gryphon deposit is designed as an underground mining operation, utilizing a conventional long hole mining approach with processing of mine production assumed at Denison's 22.5% owned McClean Lake mill. Taken together, the project is estimated to have mine production of 109.4 million pounds U3O8 over a 14-year mine life, with a base case pre-tax Net Present Value of $1.31 billion (8% discount rate), Internal Rate of Return of 38.7%, and initial preproduction capital expenditures of $322.5 million.

In December, the Company's Board of Directors and the WRJV each approved the advancement of the Wheeler River project, following a detailed assessment of the robust economic results demonstrated in the PFS.


In June 2019, the Canadian Nuclear Safety Commissions and the Saskatchewan Ministry of Environment accepted the Provincial Technical Propoal and Federal Project Description submitted by Denison for the ISR uranium mine and processing plant proposed for the Wheeler River Project. This acceptance initiated the Environmental Assessment process for Wheeler River in accordance with the requirements of both the Canadian Environmental Assessment Act, 2012 and the Saskatchewan Environmental Assessment Act.

Also in June, the Company announced that it had executed a series of Memoranda of Understanding in support of the Wheeler River Project, with certain Indigenous communities who assert that Wheeler River falls partially or entirely within their traditional territories and where traditional land use activities are currently practiced within the local and regional area surrounding the project. These non-binding MOUs formalize the signing parties’ intent to work together in the spirit of mutual respect and cooperation, in order to collectively identify practical means by which to avoid, mitigate, or otherwise address potential impacts of the project upon the exercise of Indigenous rights, Treaty rights, and other interests, as well as to facilitate sharing in the benefits that are expected to flow from the project.

In July, Denison’s Closed Mines group entered into a new two-year services agreement with Rio Algom Limited, a subsidiary of BHP Billiton Limited. Under the terms of the agreement, the Closed Mines group is responsible for carrying out the management and operation of nine of Rio Algom’s decommissioned mine sites in Ontario and Quebec from July 1, 2019 to June 30, 2021, which services include the operation of water treatment plants and tailings management facilities; environmental monitoring and compliance, data management, and regulatory reporting; maintenance of roads, dams and electrical infrastructure; site management, including health and safety, procurement, logistics, and budgeting activities; and project management and execution for various projects, including infrastructure upgrades and replacements, engineering and environmental programs, as well as water management initiatives.

 In December, Denison reported the completion of a highly successful ISR field program at Phoenix. The 2019 ISR field program was designed to validate the permeability of Phoenix, and to collect an extensive database of hydrogeological data to further evaluate the ISR mining conditions present at Phoenix. This detailed data is expected to facilitate detailed mine planning as part of the completion of a future  feasibility Study. The ISR field program, as described above, successfully achieved each of its planned objectives.


In March, Denison announced the temporary suspension of Wheeler River EA activities, and adjustments to its prior 2020 Outlook, amidst the significant social and economic disruption resulting from the COVID-19 pandemic and the Company's commitment to ensure employee safety, support public health efforts to limit transmission of COVID-19, and exercise prudent financial discipline.

In June, the Company announced the completion of independent hydrogeologic modeling for the Phoenix deposit at Wheeler River, based on site-specific data collected from the 2019 ISR field program, which produced demonstration of “proof of concept” for the application of the ISR mining method at Phoenix, with respect to potential operational extraction and injection rates, a significant milestone in de-risking the technical risks identified in the 2018 PFS.

In July, Denison announced the resumption of ISR field testing activities at Phoenix, with the commencement of the 2020 ISR field program. The work was intended to build additional confidence in the results of the hydrogeologic model developed for the deposit, and to support further field work expected to be required for the completion of a future FS.

Also in July, the Company announced the completion of a conceptual mining study, evaluating the use of the ISR mining method, for the J Zone deposit at the Waterbury Lake project and the initiation of a preliminary economic assessment.

And in July, Denison announced the London Court of International Arbitration had rendered a final award in favour of Denison in the arbitration between Denison and Uranium Industry a.s. (“UI”) 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”). The arbitration panel declared that UI violated its obligations to the Company under the related agreements, and ordered UI to pay the Company US$10,000,000 plus interest at a rate of 5% per annum from November 16, 2016, plus certain legal and arbitration costs. The arbitration panel further dismissed all other claims and counterclaims.

In October, Denison provided an update on field activities at Wheeler River, with the completion of its 2020 ISR field program at Phoenix and the commencement of an ~12,000 metre exploration drilling program designed to test initially for extensions to known mineralization at Phoenix and then advance to regional targets for the discovery of satellite uranium deposits potentially amenable to ISR mining. The ISR field program included the installation of five additional monitoring wells in two clusters, which will allow for long-term monitoring and the modelling of groundwater impacts through construction, operations and decommissioning of the Phoenix project, each of which will be an important element of the effect assessment in an Environmental Impact Statement.

In November, Denison announced its decision to restart the formal EA process for Wheeler River effective January 2021. The decision to resume the EA process marked the end of the temporary suspension announced in March 2020 amidst the significant social and economic disruption that emerged as a result of the COVID-19 pandemic.

Also in November, Denison announced the successful completion of the independent PEA for the Waterbury Lake property evaluating the potential use of the ISR mining method at the THT deposit. The PEA was completed in accordance with NI 43-101. The THT ISR operation is estimated to produce total mine production of 9.7 million pounds U3O8 (177,664 tonnes at 2.49% U3O8) over an approximate six year mine-life with final processing occurring at Denison’s 22.5% owned McClean Lake mill with a base case pre-tax NPV of $177 million (8% discount rate), IRR of 39.1%, and initial capital expenditures of $111.6 million, excluding pre-construction evaluation and development costs.

In December, Denison announced the completion of a trade-off study assessing the merit of adopting a freeze wall design as part of the ISR mining approach planned for Phoenix. Based on the results of the trade-off study, it was determined that a freeze wall design has the potential to offer significant environmental, operational, and financial advantages compared to the freeze cap (or freeze "dome") design previously planned for the project and included in the Wheeler PFS. Accordingly, the Company has decided to adapt its plans for the Project to use a freeze wall in future Project design and environmental assessment efforts.

2021 Recent Developments

In January, the Company reported the results from its 2020 regional exploration program at Wheeler River, which included the discovery of new high-grade unconformity-hosted uranium mineralization up to 7.66% U3O8.  Drill hole WR-741AD2, which was completed along the K West conductive trend on the western side of the Wheeler River property, intersected high-grade uranium mineralization approximately four kilometers north northwest of Phoenix. Similar to Phoenix, uranium mineralization discovered in WR-741AD2 is interpreted to straddle the unconformity contact of the underlying basement rocks and the overlying Athabasca Basin sandstone. In addition to high-grade uranium, the assay results from WR-741AD2 are highlighted by the presence of high-grade nickel.

In February, Denison announced that the company finalized its 2021 plans for the further advancement of the Wheeler River project and additional field testing activities for the de-risking of the application of the ISR mining method at Phoenix.

Also in February, the Company reported the results from the 2020 exploration and expansion drilling program focused on the area proximal to the Phoenix deposit at Wheeler River. As part of this program, 21 drill holes were completed for a total of approximately 8,100 metres – all of which were located outside of the extents of the mineral resources currently defined at Phoenix. The results from the program were highlighted by the intersection of high-grade uranium mineralization in Zone C, where no mineral resource is currently estimated: 5.69% U3O8 over 5.0 metres in WR328D1, located approximately 22 metres northeast of historic mineralized hole WR-368 (1.59% U3O8 over 2.0 metres); and 8.84% U3O8 over 2.5 metres in WR-767D1, located approximately 35 metres to the northeast of WR-328D1.

In March, the Company announced its inclusion in the S&P/TSX Composite Index – the headline index for the Canadian equity market – effective prior to the open of trading on Monday March 22, 2021.

And in March, the Company announced a project finance initiative to acquire physical uranium, intended to enhance its ability, if a future decision is made to advance Wheeler River into construction, to (i) access future project financing with the potential collateralization of the uranium holdings and/or (ii) provide the Company with increased flexibility to negotiate long-term uranium supply arrangements with future customers.


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