Denison Announces Commencement of Conventional Ore Processing at White Mesa Mill

Denison Mines Corp. ("Denison") (TSX: DML)(AMEX: DNN) is pleased to announce that processing of conventional ore at Denison's White Mesa mill in Utah began on Monday April 28th. Initial testing of the grinding circuit began on April 21st, with the first ore from Tony M mine fed to the leach circuit on April 28, 2008.

Over the next 30 to 45 days, the mill will be processing uranium-only ore from the Tony M operation and will then switch to the uranium/vanadium ores from the company's Colorado Plateau mines. Currently, there are approximately 150,000 tons of ore from the various Company owned mines on the stockpile at the mill.

The completion of the modernization of the mill's vanadium circuit and the relining of tailings Cell 4A is continuing on schedule. Ron Hochstein, Denison's President and COO stated "this is a great achievement by the staff and contractors at White Mesa who have modernized the facility while continuing operations on alternate feed material, and without a lost time accident."

Denison is projecting production of between 1.4 and 1.7 million pounds of U3O8 and 3.0 to 4.0 million pounds of vanadium pentoxide from White Mesa in 2008. Currently, Denison has approximately 170,000 pounds of U3O8 in inventory from the processing of alternate feed materials in the first four months of 2008.

Denison is also pleased to announce that as a result of prior contractual arrangements, the company is receiving another shipment of high grade alternate feed material that contains about 600,000 pounds U3O8. This material could be processed in parallel with the conventional ore. This would entail construction of a separate circuit. The additional production will all be credited to Denison's account. The construction and operation of the circuit is conditional upon receipt of regulatory approvals.

About Denison

Denison Mines Corp. is a premier intermediate 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. Further, the Company has ownership interests in two of the four conventional uranium mills operating in North America today. The Company also has a strong exploration and development portfolio with large land positions in the United States, Canada, Mongolia and Zambia.

This news release contains "forward-looking statements", 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 Mines Corp. ("Denison").

Forward looking statements include, but are not limited to, statements with respect to estimated production; the development potential of Denison's properties; the future price of uranium; the estimation of mineral reserves and resources; the realization of mineral reserve estimates; the timing and amount of estimated future production; costs of production; capital expenditures; success of exploration activities; permitting time lines and permitting, mining or processing issues; currency exchange rate fluctuations; government regulation of mining operations; environmental risks; unanticipated reclamation expenses; title disputes or claims; and limitations on insurance coverage. 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".

Forward looking statements are based 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, including but not limited to risks related to: unexpected events during construction, expansion and start-up; variations in ore grade, tonnes mined, crushed or milled; delay or failure to receive board or government approvals; timing and availability of external financing on acceptable terms; actual results of current exploration activities; conclusions of economic evaluations; changes in project parameters as plans continue to be refined; future prices of uranium and vanadium; possible variations in ore reserves, grade or recovery rates; failure of plant, equipment or processes to operate as anticipated; accidents, labour disputes and other risks of the mining industry; delays in the completion of development or construction activities, as well as those factors discussed in or referred to under the heading "Risk Factors" in Denison's Annual Information Form dated March 28, 2008 available at http://www.sedar.com/ and its Form 40-F available at http://www.sec.gov/. Although management of Denison has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended.

There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. Denison does not undertake to update any forward-looking statements that are incorporated by reference herein, except in accordance with applicable securities laws. Mineral resources, which are not mineral reserves, do not have demonstrated economic viability. Readers should refer to the Annual Information Form and the Form 40-F of the Company for the year ended December 31, 2007 and other continuous disclosure documents filed since December 31, 2007 available at http://www.sedar.com/, for further information relating to their mineral resources and mineral reserves.

Cautionary Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Resources: This news release uses the terms "Measured", "Indicated" and "Inferred" Resources. United States investors are advised that while such terms are recognized and required by Canadian regulations, the United States Securities and Exchange Commission does not recognize them. "Inferred Mineral Resources" have a great amount of uncertainty as to their existence, and as to their economic and legal feasibility. It cannot be assumed that all or any part of an Inferred Mineral Resource will ever be upgraded to a higher category. Under Canadian rules, estimates of Inferred Mineral Resources may not form the basis of feasibility or other economic studies. United States investors are cautioned not to assume that all or any part of Measured or Indicated Mineral Resources will ever be converted into Mineral Reserves. United States investors are also cautioned not to assume that all or any part of an Inferred Mineral Resource exists, or is economically or legally mineable.

Contacts:Denison Mines Corp.E. Peter Farmer(416) 979-1991 ext. 231Denison Mines Corp.Ron Hochstein(604) 689-7842Denison Mines Corp.James Anderson(416) 979-1991 ext. 372(416) 979-5893Website: http://www.denisonmines.com/