Corporate History

The Denison of today is the result of a series of strategic acquisitions, amalgamations and divestitures by its predecessor companies.

The Denison name has a long history in the Canadian uranium mining industry. Based on company archives, the Company's involvement in the uranium mining industry dates back to 1954, when a predecessor to modern Denison acquired uranium claims in the Elliot Lake region of Ontario, Canada.

The Denison Mine was the longest continuous uranium mining operation in the Elliot Lake, Ontario area, with operations running from 1957 to 1992, during which time it produced 69 million tonnes of ore.

1993:  The McClean Lake Joint Venture (“MLJV”) was established, and Denison obtained its 22.5% interest in the McClean Lake project.

1995:  Development of the McClean Lake project began, with mill construction. Mining operations occurred on several deposits from 1996 to 2008:  JEB (1996 to 1997), Sue C (1997 to 2002), Sue A (2005 to 2006), Sue E (2005 to 2008) and Sue B (2007 to 2008).

1997:  Denison formed its Denison Environmental Services division in 1997 to provide mine decommissioning and mine care and maintenance services to industry and government, as well as to manage Denison’s post mine closure environmental obligations on its Elliot Lake landholdings.  Denison still proudly retains a talented technical team, principally located in Elliot Lake, Ontario, that remains focused on long-term monitoring and other post-closure mine care and maintenance services for Denison’s legacy mines.

1999:  McClean Lake ore processing activities reached commercial production and operated until the end of June 2010, producing approximately 50 million pounds U₃O₈,

2004:  Preliminary study work began by the MLJV, on what would become the Surface Access Borehole Resource Extraction (“SABRE”) mining program.

2006:  The formation of the modern corporate Denison, when International Uranium Corp. acquired Denison by plan of arrangement and changed its name to Denison Mines Corp.

2012:  Denison sold its US Mining Division, which included 100% ownership of the White Mesa Mill in Utah, to Energy Fuels Inc.

2013:  Denison acquired JNR Resources Inc., Fission Energy Corp. and Rockgate Capital Corp.

2014:  The McClean Lake mill re-commenced operations under a toll milling agreement with the delivery of ore shipments from the Cigar Lake Mine, owned by the Cigar Lake Joint Venture and operated by Cameco.

2015:  Denison sold its interest in the Gurvan Saihan joint venture in Mongolia to Uranium Industry a.s.

2016:  McClean Lake mill expansion was completed, allowing for the licensed production capacity of the mill to increase to 24 million pounds U₃O₈ per year. Processing of Cigar Lake mine ore production is up to 18 million pounds U₃O₈ per year, and the mill has capacity to process ore from other sources in the future.

2016:  Denison sold its subsidiary Rockgate, which had been reorganized to hold Denison’s varied uranium mineral interests in Zambia, Mali and Namibia, to GoviEx Uranium Inc.

2017:  Denison increased its interest in its flagship Wheeler River project, to approximately 66%.

2017-2019:  Denison 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 formalized 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 Wheeler River project.

2018:  Denison acquired Cameco Corporation’s 24% in the Wheeler River project, increasing its interest to 90%, with the remaining 10% held by JCU (Canada) Exploration Limited.

2018:  Denison announced the results of the Pre-Feasibility Study for the Wheeler River project, highlighted by the selection of the in-situ recovery (“ISR”) mining method for the development of the high-grade Phoenix deposit.

2019:  The Canadian Nuclear Safety Commissions and the Saskatchewan Ministry of Environment accepted the Provincial Technical Proposal 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.

2020:  Denison announced the results of the Preliminary Economic Assessment for the Waterbury Lake property evaluating the potential use of the ISR mining method at the Tthe Heldeth Túé (“THT”) deposit.  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.

2021 – March:  Denison entered into a Participation and Funding Agreement and Letter of Intent with the English River First Nation (“ERFN”) in connection with the advancement of the proposed ISR mining operation at Wheeler River, as well as an Exploration Agreement in respect of Denison’s exploration and evaluation activities within the ERFN traditional territories. These agreements reflect Denison’s desire to operate its business in a progressive and sustainable manner that respects ERFN rights and advances reconciliation with Indigenous peoples. The agreements provide ERFN with economic opportunities and other benefits, and establish a foundation for future collaboration in an authentic, cooperative, and respectful way.

2021 - March:  Denison 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.

2021 - March:  Denison completed a strategic acquisition of 2.5 million pounds U₃O₈, at a weighted average price of US$29.66 per pound U₃O₈ (including purchase commissions of US$0.04 per pound U₃O₈) and a total cost of approximately US$74.15 million.  The uranium spot price appreciated to US$42.00 per pound U₃O₈ by December 31, 2021, resulting in a fair value gain on Denison’s physical uranium holdings of approximately $41.4 million for the year ended December 31, 2021.

2021 - August:  Denison acquired 50% of JCU, with the other 50% held by UEX Corporation, thereby increasing Denison’s effective interest in the Wheeler River project to 95%.  Through its 50% ownership of JCU, Denison holds additional interests in various uranium project joint ventures in Canada, including the Millennium project (JCU 30.099%), the Kiggavik project (JCU 33.8123%) and Christie Lake (JCU 34.4508%).

2021 - November:  Denison announced the MLJV’s completion of a SABRE test mining program at McClean North.  The SABRE field test ran safely from May to September 2021 with four cavities mined and the recovery of approximately 1,500 tonnes of high-value ore ranging in grade from 5% to 16% U₃O₈. The program was concluded successfully with no safety, environmental or radiological incidents. Importantly, key operating objectives associated with the test program – including targets for cavity diameter, rates of recovery, and mine production rates – were all achieved during the field test.

2021 - December:  Denison formally adopted an Indigenous Peoples Policy, which reflects the Company’s recognition of the important role of Canadian business in the process of reconciliation with Indigenous peoples in Canada and outlines the Company’s commitment to take action towards advancing reconciliation.  https://denisonmines.com/site/assets/files/6165/indigenous_peoples_policy.pdf

2022 - January:  The CNSC approved the amendment to the Mine Operating License for the McClean Lake operation to further extend the capacity and life of the tailings management facility.  

2022 - 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 Indigenous People’s Policy and advancing reconciliation through taking action.

2022 - August: Denison announced it had obtained all necessary permitting to conduct the planned ISR feasibility field test (“FFT”) at the Phoenix deposit at Wheeler River, designed to provide further verification of the permeability, leachability, and containment parameters needed for the successful application of the ISR mining method at Phoenix.

2022 - October: Denison 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.

2022 - October: Denison achieved a significant regulatory milestone for Wheeler River with the submission of the draft Environmental Impact Statement 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.

2023 - June: In June 2023, Denison released the results of the Feasibility Study (‘Phoenix FS’) completed for ISR mining of the Wheeler River Phoenix deposit.  The Phoenix FS demonstrates robust economics including:

• Base case pre-tax Net Present Value (‘NPV’) (8%) of $2.34 billion (100% ownership-basis) representing a 150% increase in the base-case pre-tax NPV_8% for Phoenix from the 2018 Pre-Feasibility Study.
• Very robust base-case pre-tax Internal Rate of Return (‘IRR’) of 105.9%.
• Adjusted base case after-tax NPV8% of $1.56 billion (100% basis) and IRR of 90.0% – with Denison’s effective 95% interest in the project equating to an adjusted base case after-tax NPV_8% of $1.48 billion.
• Base case pre-tax and after-tax (adjusted) payback period of 10 months – equating to a reduction of 11 months for the pre-tax payback period from the 2018 PFS.
• Optimized production profile, based on ISR mine planning efforts evaluating production potential for individual well patterns – resulting in an increase to the planned rate of production by approximately 43% during the first five years of operations.
• Estimated pre-production capital costs of under $420 million (100% basis), yielding an impressive base-case after-tax (adjusted) NPV to initial capital cost ratio in excess of 3.7 to 1.
• Robust economics that easily absorb cost-inflation and design changes impacting both operating and capital costs, confirming Phoenix’s estimated cash operating and all-in costs to be amongst the lowest-cost uranium mining projects in the world.
• Phoenix FS plans aligned and costed to meet or exceed environmental criteria expected to be required by the ongoing regulatory approval process.
• Updated mineral resource estimate, reflecting the results of 70 drill holes completed in support of ISR de-risking and resource delineation activities, which has upgraded 30.9 million pounds U₃O₈ into measured mineral resources.  The updated mineral resource also resulted in an increase to the average grade of the Zone A high-grade domain, which is now estimated to contain 56.3 million pounds U₃O₈ in Measured and Indicated mineral resources at an average grade of 46.0% U₃O₈.
• Upgraded 3.4 million pounds U₃O₈ into Proven mineral reserves, representing the equivalent of 85% of production planned during the first calendar year of operations.

2023 - June: Denison also completed a cost update to the 2018 PFS for conventional underground mining of the basement-hosted Gryphon deposit at Wheeler River. The scope of the Gryphon Update was targeted at the review and update of capital and operating costs. Mining and processing plans remain largely unchanged from the 2018 PFS aside from minor scheduling and construction sequencing optimizations. The key points include:

• Base case pre-tax NPV (8%) of $1.43 billion (100% basis) is a 148% increase in the base-case pre-tax NPV_8% for Gryphon from the 2018 PFS.
• Strong base-case pre-tax IRR of 41.4%.
• Base case after-tax NPV_8% of $864.2 million (100% basis) and IRR of 37.6% – with Denison’s effective 95% interest in the project equating to a base case after-tax NPV_8% of $821.0 million.
• Base case pre-tax payback period of 20 months, and base case after-tax payback period of 22 months – equating to a reduction of 17 months for the pre-tax payback period from the 2018 PFS.
• Importantly, Gryphon remains a highly valuable project that provides Denison with an additional source of low-cost potential production to deploy significant free cash flows expected from Phoenix.
• $113 million raised through equity financings to fund operations and the advancement of Phoenix.

2023 - September:  Denison and ERFN signed a landmark Shared Prosperity Agreement supporting the development and operation of Wheeler River. The SPA received support from a substantial majority of ERFN members who participated in a ratification vote on its key terms.  The signing of the SPA follows years of active engagement, including a four-month-long ERFN-led community consultation process ahead of the ratification vote, and represents a significant milestone in the history of both Denison's relationship with ERFN and the Project.  The SPA acknowledges that the Project is located within ERFN’s Ancestral Lands, describes a mutual commitment to maintain an open, respectful, and cooperative relationship between Denison and ERFN to ensure mutual prosperity as the development and operation of the Wheeler River project, and provides Denison with ERFN’s consent to advance the project.

2023 - November:  Denison announced the completion of an inaugural ISR field test program at the THT deposit on the Waterbury Lake property. The program included (i) the installation of an eight well ISR test pattern designed to collect an initial database of hydrogeological data, (ii) testing of a permeability enhancement technique, (iii) the completion of hydrogeologic test work, highlighted by the achievement of hydraulic conductivity values consistent with those from the 2020 Preliminary Economic Assessment, and (iv) the execution of an ion tracer test which established a 10 hour breakthrough time between the injection and extraction wells, while also demonstrating hydraulic control of the injected solution. Overall, the program successfully achieved each of its planned objectives.