Denison Announces Court Denies Preliminary Injunction to Suspend Operations at Arizona 1 Mine

TORONTO, ONTARIO -- (Marketwire) -- 06/17/10 -- Denison Mines Corp. (TSX: DML)(NYSE Amex: DNN) ('Denison' or the 'Company') is pleased to report that the United States District Court for the District of Arizona has denied a motion for a preliminary injunction filed by the Center for Biological Diversity, Grand Canyon Trust, Sierra Club, Kaibab Band of Paiute Indians of the Kaibab Indian Reservation, and Havasupai Tribe (the 'Plaintiffs') to halt operations at Denison's Arizona 1 mine.

The Court heard oral argument on June 11, 2010, from the Plaintiffs, Denison, and the U.S. Department of Justice, the latter of which represented Mr. Ken Salazar, Secretary of the Interior and the U.S. Bureau of Land Management ('BLM'). On the basis of the submissions of the parties and the oral argument, the Court ruled that the Plaintiffs have not shown that they are likely to succeed on the merits of their claims that (1) Denison's existing mining plan of operations was invalid, and that BLM was obligated to require a new mining plan of operations before mining could continue, and (2) that BLM failed to supplement its prior environmental review of environmental impacts from operations at the Arizona 1 mine. As a result, the motion for a preliminary injunction was denied.

The Arizona 1 mine is an underground uranium mine located approximately 45 miles south west of Fredonia, Arizona. The mine is 100% owned by Denison Arizona Strip LLC, and operated by Denison Mines (USA) Corp. Ore production began in December 2009. The mine currently is projected to produce approximately 21,100 tons grading 0.49% U3O8 in 2010.

About Denison

Denison Mines Corp. is a mid-sized uranium producer in North America, with mining assets in the Athabasca Basin region of Saskatchewan, Canada and the southwest United States including Colorado, Utah, and Arizona. The Company also has ownership interests in two of the four conventional uranium mills currently operating in North America. Denison also has a portfolio of exploration and development projects in the United States, Canada, Mongolia and Zambia.

Cautionary Statements Regarding Forward Looking Information

Certain information contained in this press release constitutes 'forward-looking information', within the meaning of the United States Private Securities Litigation Reform Act of 1995 and similar Canadian legislation concerning the business, operations and financial performance and condition of Denison.

Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as 'plans', 'expects' or 'does not expect', 'is expected', 'budget', 'scheduled', 'estimates', 'forecasts', 'intends', 'anticipates' or 'does not anticipate', or 'believes', or variations of such words and phrases or state that certain actions, events or results 'may', 'could', 'would', 'might' or 'will be taken', 'occur' or 'be achieved' and 'has the potential to'.

Forward looking statements are based on the assumptions noted in this press release and on the opinions and estimates of management as of the date such statements are made, and they are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Denison to be materially different from those expressed or implied by such forward-looking statements. Denison believes that the expectations reflected in this forward-looking information is reasonable, but no assurance can be given that these expectations will prove to be correct and such forward-looking information included in this press release should not be unduly relied upon. This information speaks only as of the date of this press release. In particular, this press release may contain forward-looking information pertaining to the following: the estimates of Denison's mineral reserves and mineral resources; uranium and vanadium production and sales volumes; capital expenditure programs, estimated production costs, exploration and development expenditures and reclamation costs; expectations of market prices and costs; supply and demand for uranium and vanadium; possible impacts of litigation on Denison; exploration, development, production and expansion plans and objectives; Denison's expectations regarding raising capital and adding to its mineral reserves through acquisitions and development; and receipt of regulatory approvals and permits and treatment under governmental regulatory regimes.

There can be no assurance that such statements will prove to be accurate, as Denison's actual results and future events could differ materially from those anticipated in this forward-looking information as a result of those factors discussed in or referred to under the heading 'Risk Factors' in Denison's Annual Information Form dated March 19, 2010, available at http://www.sedar.com and its Form 40-F for the financial year ended December 31, 2009, available at http://www.sec.gov, as well as the following: global financial conditions; volatility in market prices for uranium and vanadium; changes in foreign currency exchange rates and interest rates; the market price of Denison's securities; the ability to access capital; the ability of Denison to meet its obligations to its creditors; liabilities inherent in mining operations; uncertainties associated with estimating mineral reserves and resources; failure to obtain industry partner and other third party consents and approvals, when required; delays in obtaining permits and licenses for development properties; competition for, among other things, capital, acquisitions of mineral reserves, undeveloped lands and skilled personnel; incorrect assessments of the value of acquisitions; geological, technical and processing problems; and, the potential influence of, or reliance upon, a business partner.

Accordingly, readers should not place undue reliance on forward-looking statements. These factors are not, and should not be construed as being, exhaustive. Statements relating to 'mineral reserves' or 'mineral resources' are deemed to be forward-looking information, as they involve the implied assessment, based on certain estimates and assumptions that the mineral reserves and mineral resources described can be profitably produced in the future. The forward-looking information contained in this press release is expressly qualified by this cautionary statement. Denison does not undertake any obligation to publicly update or revise any forward-looking information after the date of this press release to conform such information to actual results or to changes in Denison's expectations, except as otherwise required by applicable legislation.

Contacts:

Denison Mines Corp.

Ron Hochstein

President and Chief Executive Officer

(416) 979-1991 Extension 232


Denison Mines Corp.

Jim Anderson

Executive Vice President and CFO

(416) 979-1991 Extension 372

(416) 979-5893 (FAX)
www.denisonmines.com