Midwest Project

Ownership

The project is owned by Denison (25.17%) and its joint venture partner, Orano Canada (74.83%) pursuant to the Midwest Joint Venture Agreement. Orano Canada is the operator of the project.

Updated Mineral Resource Estimate

The Company retained SRK Consulting to independently review and audit an updated mineral resource estimate for the Midwest project completed by Orano Canada in November 2017.The review and audit was done in accordance with CIM Definition Standards (2014) and NI 43-101. The Company received a memorandum from SRK Consulting dated March 9, 2018, which was incorporated into the Midwest Technical Report.

Midwest Main

The Midwest Main deposit is lens to cigar shaped, 600 metres long, 10 to over 100 metres wide, with thicknesses ranging from five metres to 10 metres. The deposit consists of a near-massive, high-grade mineralized core that straddles the unconformity approximately 210 metres below surface. The high-grade core is surrounded by lower-grade, more dispersed, fracture-controlled mineralization in both sandstone and, in minor amounts, in basement rocks. The high-grade mineralization forms a roughly flat-lying lensoid concentration, with a root extending down into the basement rocks along a steeply-dipping fault.

Midwest A

The Midwest A deposit is approximately 450 metres long, 10 to 60 metres wide, ranges up to 70 metres in thickness and occurs between 150 and 235 metres below surface. Mineralization straddles the unconformity contact with minor amounts hosted within basement structures immediately below the unconformity. Thicker zones of mineralization above the unconformity are concentrated in conglomerate units at the base of the Athabasca sandstone.Similar to Midwest Main, a high-grade core of mineralization is surrounded by a lower-grade, more dispersed, fracture-controlled envelope.

Estimated Mineral Resources

Notes:

1. The Mineral Resource estimate was audited for the Company by SRK Consulting in accordance with CIM Definition Standards (2014) and NI 43-101.
2. Mineral Resources for the Midwest Main and Midwest A deposits are reported above a cut-off grade of 0.1% U₃O₈.

References

Technical Report with an Updated Mineral Resource Estimate for the Midwest Property, Northern Saskatchewan, Canada, dated March 26, 2018, by Dale Verran, MSc, P.Geo, Pr.Sci.Nat. and Chad Sorba, P.Geo, of Denison Mines Corp. and G. David Keller, P.Geo, and Oy Leuangthong, P.Eng, of SRK Consulting.

The information of a scientific and technical nature has been reviewed and approved by a Qualified Person in accordance with the requirements of NI 43-101.