Denison Announces the Commencement of a 7,500 Metre Drilling Program on the Wheeler River Uranium Property

08:31 EDT Tuesday, September 29, 2009

TORONTO, ONTARIO--(Marketwire - Sept. 29, 2009) - Denison Mines Corp. (TSX:DML) (NYSE Amex:DNN) ("Denison" or the "Company") announces a 7,500 metre drill program on the Wheeler River Property in the Athabasca Basin of northern Saskatchewan to further define the high-grade Phoenix discovery made in 2009. The Wheeler River project is a joint venture among Denison, who is the operator and holds a 60% interest, Cameco Corp. (30% interest) and JCU (Canada) Exploration Company, Limited (10% interest).

New Drill Program

The Phoenix uranium discovery has the potential to develop into a deposit of major importance in Saskatchewan. In order to accelerate the evaluation of this discovery, a 7,500 metre, 15 hole drill program has been initiated. This drill program will include eight drill holes around hole WR-273, which intersected 62.6% U3O8 over 6.0 metres. Four drill holes are also planned to further evaluate the area around WR-258 and WR-259, which intersected 11.8% U3O8 over 5.5 metres and 17.8% U3O8 over 4.5 metres, respectively. The balance of the program will test other priority targets along the one kilometre strike length of the Phoenix discovery. The budget for this drill program is $1.5 million and the results will be released following completion of the work.

Summer Drill Program

Assay results have been received for all the holes drilled this summer on the Wheeler River Property. A total of 11 holes (WR-270-280 inclusive) were completed during the summer program. Table 1 lists the drill hole assays with significant uranium intersections. Assay results for drill holes WR-270, 272, 273, 274, and 276 of the summer program have not only confirmed, but have substantially increased the high-grade down-hole probe results previously reported. Hole WR-275 was lost in altered sandstone just above the unconformity while five of the remaining six drill holes did not intersect significant mineralization, but did intersect intense alteration typically associated with uranium mineralization. The Phoenix zone has now been tested over a strike length of one kilometre, and remains open along strike.

Drill hole WR-279, intersected 0.26% U3O8 over 0.5 metres from a depth of 520.5 metres, in the basement, 117.0 metres below the unconformity, as well as graphite, which is considered important in the formation of Athabasca Basin deposits. This intersection may be indicative of the potential for basement-hosted mineralization up or down-dip from this drill hole. Strong alteration and structure encountered in hole WR-280 may be indicative of nearby mineralization. Further drilling will be carried out in these areas.

All drill holes reported to date were drilled at -80 degrees, and while the exact attitude of the mineralization remains uncertain, it is believed, at this time, that the mineralized intervals represent near true widths. All results are now reported at a 0.05% U3O8 cut-off.

The Wheeler River Property, which hosts the Phoenix discovery, is located in the Athabasca Basin between the McArthur River and Key Lake operations. This discovery has many geological similarities to the McArthur River deposit but is at a shallower depth.

Table 1. Summer Drill Program Results (see Map)

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Hole # From To Interval Assay Grade
(m) (m) (m) (%U3O8)
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WR-270 376.0 377.0 1.0 0.96

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WR-272 411.0 415.5 4.5 4.13
And 416.0 416.5 0.5 0.15
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WR-273 405.0 411.0 6.0 62.60

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WR-274 409.7 418.0 8.3 4.83
And 423.5 424.0 0.5 0.11
And 425.0 426.5 1.5 0.47
And 429.0 430.5 1.5 2.84
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WR-276 411.0 412.0 1.0 0.32
And 412.0 415.0 3.0 1.29
And 418.5 420.5 2.0 0.36
And 422.0 424.0 2.0 1.57
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WR-279 494.0 495.0 1.0 0.07
And 497.5 498.0 0.5 0.11
And 520.5 521.0 0.5 0.26
And 540.0 541.0 1.0 0.06
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The technical information contained in this press release related to the above described exploration activities is reported and verified by William C. Kerr, Denison's Vice President, Exploration, who is a qualified person as defined by NI 43-101. For a description of the quality assurance program and quality control measures applied by Denison, please see Denison's Annual Information Form dated March 26, 2009 filed under the Company's profile on the SEDAR website.

WHEELER RIVER Property Map:http://media3.marketwire.com/docs/dml929.pdf