Denison Mines Corp. Provides Date for Second Quarter 2012 Results and Conference Call

Atrium on Bay, 595 Bay Street, Suite 402 Toronto, ON M5G 2C2 Ph. 416-979-1991 • Fx. 416-979-5893 • www.denisonmines.com

PRESS RELEASE

Denison Mines Corp. Provides Date for Second Quarter 2012 Results and Conference Call

July 31, 2012 (DML:TSX; DNN:NYSE MKT) Denison Mines Corp. ("Denison" or the "Company") announces that the Company will issue its second quarter 2012 results in the evening on Thursday, August 9, 2012. Denison will hold a telephone conference with a webcast presentation at 9:00 am ET on Friday, August 10, 2012 to discuss financial results for the second quarter ending June 30, 2012.

Please call in 5-10 minutes before the conference starts and stay on the line (an operator will be available to assist you). The call-in number is (416) 340-2217.

To view the live presentation, please log on at www.denisonmines.com 10 minutes prior to the call.

Approximately two hours after the call:

a replay of the telephone conference will be available at 905-694-9451 and the passcode is  6011854; and the presentation will be available at www.denisonmines.com.

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About Denison

Denison Mines Corp. is a uranium exploration and development company with interests in exploration and development projects in Saskatchewan, Zambia and Mongolia. As well, Denison has a 22.5% ownership interest in the McClean Lake uranium mill, located in northern Saskatchewan, which is one of the world’s largest uranium processing facilities. Denison’s exploration project portfolio includes the world-class Phoenix deposit located on its 60% owned Wheeler River project also in the Athabasca Basin region of Saskatchewan.

Denison is engaged in mine decommissioning and environmental services through its Denison Environmental Services (DES) division. Denison is also the manager of Uranium Participation Corporation (TSX-U), a publicly traded company which invests in uranium oxide in concentrates and uranium hexafluoride.

For further information, please contact:

Ron Hochstein (416) 979-1991 ext. 232 President and Chief Executive Officer

James Anderson (416) 979-1991 ext. 372 Executive Vice President & Chief Financial Officer