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Denison Mines Denison Mines Corp. 1100-40 University Ave Toronto , ON M5J 1T1 www.denisonmines.com PRESS RELEASE DENISON REPORTS RESULTS FROM Q3 2021 Toronto , ON – November 4 , 2021. Denison Mines Corp. ( ' Denison ' or the ' Company ' ) ( TSX : DML , NYSE American : DNN ) today filed its Condensed Interim Consolidated Financial Statements and Management's Discussion & Analysis ( ' MD & A ' ) for the quarter ended September 30 , 2021. Both documents will be available on the Company's website at www.denisonmines.com or on SEDAR ( at www.sedar.com ) and EDGAR ( at www.sec.gov/edgar.shtml ) . The highlights provided below are derived from these documents and should be read in conjunction with them . All amounts in this release are in Canadian dollars unless otherwise stated . David Cates , President and CEO of Denison commented , " Our recent In - Situ Recovery ( ' ISR ' ) field test results reflect several years of progress made towards systematically de - risking the use of the ISR mining method at the high - grade Phoenix deposit - culminating in the successful , and first of its kind , field test of a commercial- scale well pattern located in the expected first phase of the Phoenix orebody . Our accomplishments in the field and the laboratory have significantly increased our confidence in the use of the ISR mining method and support our landmark decision to advance the planned Phoenix ISR operation to the Feasibility Study design stage . With increased interest in the uranium market and a recent lift in both spot and long - term uranium prices , we are encouraged that future utility customers are returning to the market and looking at Denison's Wheeler River project as a potentially viable source of reliable and low - cost future supply . Taken together with our effective 95 % interest in Wheeler River and strong balance sheet , which , as of today , includes 2.5M lbs U308 of physical uranium holdings acquired at a price under US $ 30 / lb U308 , we believe Denison is well positioned to become an intermediate supplier of choice in the second half of the decade at a time when market fundamentals are predicted to be favourable as a result of growing demand for uranium and a relative shortage of advanced low - cost uranium development assets in stable jurisdictions . Our team is focused on advancing Phoenix in the coming months and years to realize on our vision of becoming the next new uranium producer in the Athabasca Basin region . " HIGHLIGHTS ■ Successful completion of ISR field test activities at Phoenix The initial results of the 2021 ISR field test program ( ' 2021 ISR Field Test ' ) completed at the Phoenix uranium deposit ( ' Phoenix ' ) include ( 1 ) the achievement of commercial - scale production flow rates consistent with those assumed in the pre - feasibility study ( ' PFS ' ) prepared for the Wheeler River Project ( ' Wheeler River ' or the ' Project ' ) in 2018 ; ( 2 ) the demonstration of hydraulic control of injected solution during the ion tracer test ; and ( 3 ) the establishment of breakthrough times between injection and recovery wells , spaced 5 to 10 metres apart , that are consistent with the hydrogeological model prepared by Petrotek Corporation ( ' Petrotek ' ) in 2020 demonstrating " proof of concept ” . In addition , the Company completed the clean - up phase following the tracer test , demonstrating the ability to remediate the commercial scale well ( ' CSW ' ) test pattern , reducing tracer concentrations to as low as 4 % of peak test levels , with eight days of remediation . ■ Advancement of Phoenix to feasibility study ( ' FS ' ) stage and selection Wood PLC as independent lead author In September 2021 , the Wheeler River Joint Venture ( ' WRJV " ) approved the initiation of an independent FS for the ISR mining operation proposed for Phoenix . The completion of the FS is a critical step in the progression of the project and is intended to advance de - risking efforts to the point where the Company and the WRJV will be able to make a definitive development decision . The Company also selected leading global consulting and engineering firm 1