TORONTO, ONTARIO--(Marketwired - Feb. 9, 2016) - Denison Mines Corp. ("Denison" or the "Company") (TSX:DML)(NYSE MKT:DNN) is pleased to announce the discovery of a new high-grade uranium intersection near the Gryphon deposit on Denison's 60% owned Wheeler River property in Northern Saskatchewan. Drill hole WR-633D1, located approximately 100 metres north of the Gryphon deposit, intersected approximately 11 metres of basement-hosted uranium mineralization including intervals of 5.7% eU3O8 over 1.0 metre and 6.3% eU3O8 over 1.7 metres.
In late 2015, Denison reported a significant increase in the estimated mineral resources on the Wheeler River property. The initial estimate for the Gryphon Deposit added inferred mineral resources of 43.0 million pounds U3O8 at a grade of 2.3% U3O8 to 70.2 million pounds U3O8 of indicated mineral resources grading 19.1% U3O8 at the Phoenix deposit. The Gryphon deposit is basement-hosted and consists of a set of parallel, stacked, northeast plunging lenses that are broadly conformable with the basement stratigraphy. Four groups of lenses have been interpreted to date, namely the A, B, C and D series, based on their position relative to the different basement stratigraphic units. The estimated mineral resources contained in the Gryphon deposit include only the results from the A, B and C series lenses. The D series lenses were excluded as there was insufficient drilling completed at the time of the resource estimate.
Denison's President and CEO, David Cates, commented, "With the successful delineation of the Gryphon deposit, completed in 2015, our exploration team set out in 2016 to discover new uranium mineralization in the vicinity of the Gryphon deposit. We view the geological trend that Gryphon is situated on as a highly prospective district for the discovery of additional mineralization, and only a few short weeks into our exploration program, the property and our exploration team have delivered again with the discovery of additional high-grade uranium mineralization."
New Intersection of High-Grade Uranium Mineralization
Drill hole WR-633D1 was designed to test for further basement-hosted mineralization immediately north of the Gryphon deposit, and down plunge of previous mineralized intercepts. The drill hole encountered the sub-Athabasca unconformity around 500 metres below surface, followed by weak basement-hosted mineralization and alteration around 675 metres, 680 metres, 682 metres and 684 metres before entering high-grade uranium mineralization around 751 metres, as detailed below in Table 1.
| Table 1: WR-633D1Intersection |
| Drill Hole | From (m) | | To (m) | | Length (m)4 | | eU3O81(%) |
| WR-633D12 | 751.5 | | 754.7 | | 3.2 | | 2.0 |
| (includes) 3 | 753.6 | | 754.6 | | 1.0 | | 5.7 |
| (and) 2 | 757.7 | | 765.3 | | 7.6 | | 1.7 |
| (includes) 3 | 760.3 | | 762.0 | | 1.7 | | 6.3 |
| (includes) 3 | 764.2 | | 765.2 | | 1.0 | | 1.2 |
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| Notes: | 1. | eU3O8 is radiometric equivalent uranium from a total gamma down-hole probe |
| | 2. | Intersection interval is composited above a cut-off grade of 0.1% eU3O8 |
| | 3. | Intersection interval is composited above a cut-off grade of 1.0% eU3O8 |
| | 4. | As the drill hole is oriented steeply toward the northwest and the basement mineralization dips moderately to the southeast, the true thickness of the mineralization is expected to be approximately 75% of the intersection lengths |
The high-grade mineralization occurs within altered pelitic gneisses and pegmatite that both occur within the Basal Pegmatite Unit and represents the best intersection to date in this unit, which has undergone little previous drill testing. The mineralization is open in all directions and will be prioritized for follow-up this winter.
Possible Continuation of the D Series Lenses
Previous 50 x 50 metre delineation drilling has shown the Gryphon mineralized lenses to be structurally controlled with a plunge to the northeast. In this regard, the mineralized intersections in drill hole WR-633D1 possibly represent the down plunge extent of some of the D series lenses located approximately 180 metres up plunge to the southwest. Additional drilling will be required to validate if the stratigraphy is continuous and if the intersection of mineralization in WR-633D1 is a continuation of the mineralization occurring in the D series lenses. The D series of lenses is currently defined by intersections from drill holes completed previously. Table 2 provides highlight intersections of the D Series lenses.
| Table 2: DSeriesLensIntersections |
| Drill Hole | From (m) | To (m) | Length (m)3 | | Assay U3O8 (%) |
| WR-5581,4 | 611.7 | 612.2 | 0.5 | | 7.3 |
| WR-5652,4 | 686.0 | 689.9 | 3.9 | | 0.6 |
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| Notes: | 1. | Intersection interval is composited above a cut-off grade of 1.0% U3O8 |
| | 2. | Intersection interval is composited above a cut-off grade of 0.1% U3O8 |
| | 3. | As the drill hole is oriented steeply toward the northwest and the basement mineralization dips moderately to the southeast, the true thickness of the mineralization is expected to be approximately 75% of the intersection lengths |
| | 4. | The intersections listed above are both from the D1 lens. Drill hole WR-558 is located approximately 140 metres up plunge to the southwest of WR-565. |
Wheeler River Property
The Wheeler River property is host to the high-grade Phoenix and Gryphon uranium deposits. The Phoenix deposit is estimated to include indicated resources of 70.2M lbs U3O8 at a grade of 19.1% U3O8, and is the highest grade undeveloped uranium deposit in the world. The Gryphon deposit is hosted in basement rock, approximately 3 kilometres to the northwest of Phoenix, and is estimated to contain inferred resources of 43M lbs U3O8 at a grade of 2.3% U3O8. Wheeler River is a joint venture between Denison (60% and operator), Cameco Corp. ("Cameco") (30%), and JCU (Canada) Exploration Company Limited (10%).
A 47,000 metre exploration drilling program is currently underway at Wheeler River with a focus on testing numerous unconformity and basement exploration targets in the vicinity of the Gryphon deposit, as well as other priority target areas on the property. Concurrent with the winter 2016 drilling program, a Preliminary Economic Assessment ("PEA") is underway studying the economic potential of co-developing the Gryphon and Phoenix deposits. The PEA is expected to be completed during the first half of 2016.
Illustrative Figures & Further Details
A property location and basement geology map is provided in Figure 1. Figure 2 provides a plan map of the northeast plunging Gryphon mineralized lenses projected up to the basement geology at the sub-Athabasca unconformity. The cross-section in Figure 3 represents section line 5187GP and illustrates the new mineralization discovered in drill hole WR-633D1, which occurs to the north of the stacked A, B and C series lenses that define the Gryphon deposit. The cross-section in Figure 4 represents section line 5050GP and illustrates the stacked lenses (A, B and C series) that define the Gryphon deposit, as well as the D series lenses, which occur up plunge of the mineralization intersected in WR-633D1 illustrated in Figure 3.
Further details regarding the Gryphon deposit and the current mineral resources estimated at Wheeler River are provided in the report titled "TECHNICAL REPORT ON A MINERAL RESOURCE ESTIMATE FOR THE WHEELER RIVER PROPERTY, EASTERN ATHABASCA BASIN, NORTHERN SASKATCHEWAN, CANADA.", dated Nov. 25, 2015, authored by William E. Roscoe Ph.D, P.Eng. and Mark B. Mathisen C.P.G of RPA. A copy of this report is available under Denison's profile on SEDAR (www.sedar.com).
Qualified Person
The disclosure of a scientific or technical nature contained in this news release was prepared by Dale Verran, MSc, Pr.Sci.Nat., Denison's Vice President, Exploration, who is a Qualified Person in accordance with the requirements of 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 5, 2015 filed under the Company's profile on SEDAR at www.sedar.com.