Denison Intersects 5.0% eU3O8 Over 4.7 Metres at the Unconformity as Definition and Expansion Drilling Continues on the Gryphon Deposit at Wheeler River

Denison Mines Corp.

TORONTO, ONTARIO--(Marketwired - Aug. 30, 2017) - Denison Mines Corp. ("Denison" or the "Company") (TSX:DML)(NYSE MKT:DNN)(NYSE American:DNN) is pleased to report the intersection of new high-grade unconformity-hosted uranium mineralization in drill hole WR-689D3 approximately 250 metres along strike to the northeast and 200 metres up-dip of the Gryphon deposit, on the Company's 60% owned Wheeler River project. Preliminary radiometric equivalent probe results ("eU3O8") from drill hole WR-689D3 are highlighted by an interval of 5.0% eU3O8 over 4.7 metres, including 8.5% eU3O8 over 2.7 metres, from mineralization occurring immediately above the sub-Athabasca unconformity that is comprised of massive to semi-massive uraninite (pitchblende) associated with hydrothermal hematite and clay alteration.