Exhibit 99.12

SRK Consulting (Canada) Inc. 1500, 155 University Avenue Toronto, Ontario, Canada M5H 3B7 T: +1.416.601.1445 F: +1.416.601.9046 toronto@srk.com www.srk.com

CONSENT

Ladies and Gentlemen:

The undersigned company hereby consents to (1) the references to the undersigned company’s name included or incorporated by reference in the Annual Report on Form 40-F of Denison Mines Corp. and the registration statement on Form F-10 (File No. 333-238108) of Denison Mines Corp. (the “Registration Statement”) in connection with the reports entitled (a) “Technical Report with an Updated Mineral Resource Estimate for the Midwest Property, Northern Saskatchewan, Canada” dated March 26, 2018, and (b) “Preliminary Economic Assessment for Tthe Heldeth Túé (J Zone) Deposit, Waterbury Lake Property, Northern Saskatchewan, Canada” with an effective date of October 30, 2020, and (2) all other references to the undersigned company included or incorporated by reference in the Annual Report on Form 40-F of Denison Mines Corp. and the Registration Statement.

Dated: March 29, 2021

SRK CONSULTING (CANADA) INC.

Per:__(Signed) Glen Cole______________

Glen Cole, PGeo

Practice Leader

SRK Consulting (Canada) Inc.

Local Offices: Saskatoon Sudbury Toronto Vancouver Yellowknife Group Offices: Africa Asia Australia Europe North America South America