Denison Announces Discovery of Additional High-Grade Mineralization at Gryphon and Reports Results from Successful Delineation Program
Denison Mines (NYSE:DNN) has announced the discovery of additional high-grade uranium mineralization at its Gryphon deposit, located approximately 3 km northwest of the Company's Phoenix ISR uranium project. A significant intersection in drill hole WR-837AD2 revealed 2.3 metres at 1.69% eU3O8, including 0.5 metres at 5.48% eU3O8, approximately 40 metres outside the previously defined D1 lens.
The discovery was part of a successful 12,500-metre delineation program completed in the first half of 2025. The Gryphon deposit contains Indicated Mineral Resources of 61.9 million pounds U3O8 at an average grade of 1.7%. The project demonstrates robust economics with an estimated after-tax NPV of $864.2 million and an IRR of 37.6%, with competitive cash operating costs of USD$12.75/lb U3O8.
Denison Mines (NYSE:DNN) ha annunciato la scoperta di ulteriore mineralizzazione di uranio ad alto tenore nel suo giacimento Gryphon, situato a circa 3 km a nord-ovest del progetto di uranio ISR Phoenix dell'azienda. Un'intersezione significativa nel foro di sondaggio WR-837AD2 ha rivelato 2,3 metri con il 1,69% di eU3O8, inclusi 0,5 metri con il 5,48% di eU3O8, a circa 40 metri al di fuori della lente D1 precedentemente definita.
La scoperta fa parte di un programma di delimitazione di 12.500 metri completato con successo nella prima metà del 2025. Il giacimento Gryphon contiene Risorse Minerarie Indicate di 61,9 milioni di libbre di U3O8 con un tenore medio dell'1,7%. Il progetto mostra solide prospettive economiche con un NPV post-tasse stimato di 864,2 milioni di dollari e un IRR del 37,6%, con costi operativi in contanti competitivi di USD 12,75 per libbra di U3O8.
Denison Mines (NYSE:DNN) ha anunciado el descubrimiento de mineralización adicional de uranio de alta ley en su depósito Gryphon, ubicado aproximadamente a 3 km al noroeste del proyecto de uranio ISR Phoenix de la compañía. Una intersección significativa en el taladro WR-837AD2 reveló 2,3 metros con 1,69% de eU3O8, incluyendo 0,5 metros con 5,48% de eU3O8, aproximadamente a 40 metros fuera del lente D1 previamente definido.
El descubrimiento formó parte de un exitoso programa de delimitación de 12,500 metros completado en la primera mitad de 2025. El depósito Gryphon contiene Recursos Minerales Indicados de 61,9 millones de libras de U3O8 con una ley promedio del 1,7%. El proyecto presenta una sólida economía con un VAN después de impuestos estimado en 864,2 millones de dólares y una TIR del 37,6%, con costos operativos en efectivo competitivos de USD 12,75 por libra de U3O8.
Denison Mines (NYSE:DNN)는 회사의 Phoenix ISR 우라늄 프로젝트에서 약 3km 북서쪽에 위치한 Gryphon 광상에서 추가 고등급 우라늄 광물화 발견을 발표했습니다. 시추공 WR-837AD2에서 중요한 교차구간이 2.3미터 구간에 1.69% eU3O8를 나타냈으며, 그 중 0.5미터 구간에 5.48% eU3O8가 포함되어, 이전에 정의된 D1 렌즈에서 약 40미터 밖에 위치해 있습니다.
이번 발견은 2025년 상반기에 완료된 성공적인 12,500미터 경계 설정 프로그램의 일부입니다. Gryphon 광상은 평균 등급 1.7%로 61.9백만 파운드의 U3O8 지정 자원을 포함하고 있습니다. 이 프로젝트는 세후 순현재가치(NPV) 8억 6,420만 달러와 내부수익률(IRR) 37.6%로 견고한 경제성을 보여주며, 경쟁력 있는 현금 운영비용은 U3O8 파운드당 미화 12.75달러입니다.
Denison Mines (NYSE:DNN) a annoncé la découverte d'une minéralisation d'uranium à haute teneur supplémentaire dans son gisement Gryphon, situé à environ 3 km au nord-ouest du projet d'uranium ISR Phoenix de la société. Une intersection significative dans le forage WR-837AD2 a révélé 2,3 mètres à 1,69% de eU3O8, incluant 0,5 mètre à 5,48% de eU3O8, à environ 40 mètres en dehors du lentille D1 précédemment définie.
Cette découverte fait partie d'un programme de délimitation de 12 500 mètres mené avec succès au cours du premier semestre 2025. Le gisement Gryphon contient des ressources minérales indiquées de 61,9 millions de livres d'U3O8 avec une teneur moyenne de 1,7%. Le projet présente une économie solide avec une valeur actuelle nette après impôts estimée à 864,2 millions de dollars et un taux de rentabilité interne (TRI) de 37,6%, avec des coûts d'exploitation compétitifs en espèces de 12,75 USD par livre d'U3O8.
Denison Mines (NYSE:DNN) hat die Entdeckung zusätzlicher hochgradiger Uranmineralisierung in seiner Gryphon-Lagerstätte bekannt gegeben, die etwa 3 km nordwestlich des Phoenix ISR-Uranprojekts des Unternehmens liegt. Ein bedeutender Abschnitt im Bohrloch WR-837AD2 zeigte 2,3 Meter mit 1,69% eU3O8, darunter 0,5 Meter mit 5,48% eU3O8, etwa 40 Meter außerhalb der zuvor definierten D1-Linse.
Die Entdeckung war Teil eines erfolgreichen 12.500 Meter umfassenden Abgrenzungsprogramms, das in der ersten Hälfte des Jahres 2025 abgeschlossen wurde. Die Gryphon-Lagerstätte enthält Indizierte Mineralressourcen von 61,9 Millionen Pfund U3O8 mit einem durchschnittlichen Gehalt von 1,7%. Das Projekt weist eine robuste Wirtschaftlichkeit mit einem geschätzten Nachsteuer-NPV von 864,2 Millionen US-Dollar und einem IRR von 37,6% auf, bei wettbewerbsfähigen Cash-Betriebskosten von 12,75 USD pro Pfund U3O8.
- Discovery of new high-grade uranium mineralization extending 40 metres beyond previous estimates
- Successful delineation program confirming geological model and grade expectations
- Robust economics with after-tax NPV of $864.2M and 37.6% IRR
- Competitive cash operating costs of USD$12.75/lb U3O8
- Significant resource base of 61.9M pounds U3O8 at 1.7% grade
- High initial capital costs requirement of CAD$737.4 million
- Project still requires additional drilling to define expansion potential
Insights
Denison's discovery expands Gryphon's high-grade uranium resource with promising drill results, enhancing the already robust project economics.
Denison Mines has made a significant discovery that extends the high-grade D1 lens at their Gryphon uranium deposit. Drill hole WR-837AD2 intersected 2.3 metres at 1.69% eU3O8 including 0.5 metres at 5.48% eU3O8 approximately 40 metres outside the previously defined mineralized domain. This represents a meaningful extension to the already substantial resource base at Gryphon.
The technical significance of this discovery cannot be overstated. The mineralization remains open both down-plunge and along strike to the northeast, suggesting substantial potential for resource expansion. Finding such high-grade uranium outside the existing resource envelope is particularly valuable, as it indicates the deposit's boundaries aren't fully constrained.
The 2025 delineation program achieved multiple objectives beyond just discovery. It confirmed the geological model of the deposit, increased drilling density in the A1 high-grade domain (which contains approximately 50% of the indicated mineral resources), and collected critical geotechnical, metallurgical and hydrogeological data for future development work. Notably, drill hole WR-831D1D2 demonstrated the exceptional grade potential of Gryphon, intersecting 11.0 metres at 1.76% eU3O8 in the A1 lens and 14.5 metres at 2.13% eU3O8 in the B3 lens.
The existing Gryphon resource estimate of 61.9 million pounds U3O8 at 1.7% grade (Indicated category) already represents one of the highest-grade undeveloped uranium deposits globally. With estimated cash operating costs of USD$12.75/lb and all-in costs of USD$25.47/lb, Gryphon is positioned to be among the lowest-cost uranium operations worldwide. The collection of 250 kg of whole-core samples for metallurgical testing and installation of vibrating wire piezometers for hydrogeological studies demonstrates Denison's methodical approach to de-risking this asset.
The new discovery announced by Denison has significant positive implications for the valuation of the Wheeler River project. Extending high-grade mineralization 40 metres beyond the current resource boundary in the D1 lens represents a meaningful growth opportunity for the Gryphon deposit. This expansion potential is particularly valuable considering the robust economics already established for this deposit.
The PFS updated in 2023 demonstrated an after-tax NPV of $864.2 million with an IRR of 37.6%, based on the existing probable reserves of 49.7 million pounds at 1.8% U3O8 and a uranium price of $75/lb. The low projected operating costs make this project exceptionally attractive in the current uranium market.
What's particularly compelling is the dual-asset nature of Wheeler River. While Phoenix advances through permitting toward becoming a low-cost ISR operation, Gryphon provides substantial growth optionality with its conventional underground mining approach. Having both deposits within proximity (just 3 km apart) creates infrastructure synergies that enhance the overall project economics.
The delineation results confirm the deposit's geological continuity and grade profile, reducing technical risk. The collection of additional metallurgical samples (250 kg of whole-core) and hydrogeological data further de-risks the project. This systematic approach to advancement demonstrates management's technical competence.
Denison's strong joint venture portfolio (including interests in McClean Lake, Midwest, Waterbury Lake, Millennium, and Kiggavik) provides additional upside beyond Wheeler River. The company's 22.5% ownership in the McClean Lake Joint Venture is particularly valuable as it includes both unmined deposits and an operating mill currently processing Cigar Lake ore. The planned extraction via the SABRE mining method starting in 2025 could generate near-term cash flow to support Denison's development activities at Wheeler River.
The discovery was made as part of a highly successful delineation drill program carried out at Gryphon during the first half of 2025. Results from the delineation drilling are expected to add confidence to the previously estimated mineral resources for Gryphon, having confirmed the current geological interpretation of the deposit and intersecting uranium grades in line with expected values.
Denison's President and CEO, David Cates, commented, "Our 2025 Gryphon delineation program was highly successful and achieved each of the program's key objectives – including (a) increasing the density of drill testing within the A1 high-grade domain and confirming the geological model, (b) collecting additional geotechnical, metallurgical and hydrogeological samples and information to support future project evaluation efforts, and (c) initial testing of areas identified for possible expansion of mineral resources that are outside of the mine design outlined in the 2023 Pre-Feasibility Study ("PFS").
The delineation results demonstrate that Gryphon is an excellent high-grade basement-hosted uranium deposit that justifies further project development evaluation and de-risking. With a focus on confirming the mineralization in the A-series of lenses, a limited number of drill holes were designed to test for possible expansion of the estimated mineral resource. As a result, we are excited that drill hole WR-837AD2 encountered high-grade mineralization outside of the existing mineralized domain in an area that remains wide open for further expansion down-plunge and along strike. We are currently developing plans to follow-up this result and test other expansion targets."
Gryphon Uranium Deposit
Gryphon was discovered by Denison in 2014 and is estimated to contain Indicated Mineral Resources of 61.9 million pounds U3O8 (1,643,000 tonnes an average grade of
Gryphon is comprised of 24 primarily basement-hosted stacked lenses referred to as the A-series, B-series, C-series, D-series and E-series lenses, which are interpreted to be stacked to form a zone of mineralization measuring approximately 280 metres long by 113 metres wide, with each lens having variable thicknesses and generally plunging to the northeast and dipping to the southeast (See Figure 2). Four high-grade domains have been established within the A1 and D1 lenses. The A1 high-grade domain represents
Potential future development of the Gryphon deposit has been assessed as an underground mining operation at a PFS level in 2018 with a cost update completed in 2023. The outcomes of the study highlight robust economics with an estimated after-tax base-case Net Present Value ("NPV") of
Discovery of Additional High-Grade Mineralization Associated with the D1 lens
The D series lenses were targeted for potential mineral resource expansion in 2025 given their high-grade, structurally controlled nature, and that previous drilling left the mineralization partially open in the down-plunge and along-strike directions. Prior to this program, no significant expansion drilling has occurred proximal to Gryphon since 2018.
The last drill hole of the 2025 program (WR-837AD2) encountered high-grade uranium mineralization, which is interpreted to expand the extent of the D1 zone by ~40 metres in the down-plunge direction. This drill hole tested a 100-metre gap in the previous drill hole spacing (see Figure 3) and justifies further follow-up drilling to test to additional down-plunge extension as well as the potential for along strike continuation. Drill hole WR-836 was also completed in the expansion area and also encountered notable uranium mineralization, which indicates the system is open along strike to the north.
Denison reports its initial drilling results as radiometric equivalent uranium ("%eU3O8") from a calibrated, triple gamma, down-hole probe. All mineralized intersections have been sampled for chemical U3O8 assay and final results will be compiled following receipt of the data.
Table 1: Drill hole intercepts by lens for WR-836 and WR-837AD2.1
Drill Hole | Lens | From | To | Length | %eU3O82 |
WR-8361 | D13 | 800.3 | 800.8 | 0.5 | 0.40 |
WR-837AD21 | D13 | 834.6 | 836.9 | 2.3 | 1.69 |
(includes)4 | 835.6 | 836.1 | 0.5 | 5.48 |
Notes: | |
1. | Drill hole orientation (azimuth/dip) for WR-836 is 306.8o/-73.4o and for WR-837AD2 is 311.1o/-71.0o |
2. | eU3O8 is radiometric equivalent uranium from a calibrated total gamma down-hole probe. All intersections have been sampled for chemical U3O8 assay |
3. | Intersection interval is composited above a cut-off grade of |
4. | Intersection interval is composited above a cut-off grade of |
5. | As most of the drill holes are oriented steeply toward the northwest and the basement mineralization is interpreted to dip moderately to the southeast, the true thickness of the mineralization is expected to be approximately |
2025 Delineation Drill Program Highlights
A total of ~12,500 metres of diamond drilling was completed in seventeen drill holes and multiple off cuts during the 2025 delineation program at Gryphon. Overall, the delineation program confirmed the current geological interpretation of the deposit and supported the grade-thickness (GT) assumptions in the resource block model.
The A1 lens was the primary focus of the drill program as the high-grade and low-grade domains contain approximately
The B and C series lenses are located below the A series within the center of the deposit and were also intersected as part of the 2025 delineation program. Together the B and C series lenses account for approximately
Several drill holes encountered significant results, demonstrating the high-grade nature of Gryphon, including the following results from WR-831D1D2, which tested the primary lenses and returned the best mineralized intercepts from the delineation program:
Table 2: Drill hole intercepts by lens for WR-831D1D2.1
Lens | From | To | Length | %eU3O82 |
A43 | 655.6 | 657.3 | 1.7 | 0.87 |
A33 | 664.9 | 667.3 | 2.4 | 0.20 |
A23 | 682.5 | 684.3 | 1.8 | 0.76 |
A13 | 689.3 | 700.3 | 11.0 | 1.76 |
(includes)4 | 692.6 | 694.4 | 1.8 | 3.85 |
(includes)4 | 695.3 | 697.2 | 1.9 | 5.28 |
B13 | 701.2 | 708.0 | 6.8 | 0.13 |
B23 | 713.0 | 717.4 | 4.4 | 0.14 |
B33 | 721.0 | 735.5 | 14.5 | 2.13 |
(includes)4 | 723.9 | 725.7 | 1.8 | 6.38 |
(includes)4 | 727.1 | 727.6 | 0.5 | 2.60 |
(includes)4 | 731.5 | 734.0 | 2.5 | 6.16 |
B3 (continued)3 | 737.5 | 743.8 | 6.3 | 0.91 |
(includes)4 | 740.1 | 740.7 | 0.6 | 3.42 |
Notes: | |
1. | Drill hole orientation (azimuth/dip) 295.8o/-77.0o |
2. | eU3O8 is radiometric equivalent uranium from a calibrated total gamma down-hole probe. All intersections have been sampled for chemical U3O8 assay |
3. | Intersection interval is composited above a cut-off grade of |
4. | Intersection interval is composited above a cut-off grade of |
5. | Intersections with less than 0.5 GT were left out of the table to simplify the results |
6. | As most of the drill holes are oriented steeply toward the northwest and the basement mineralization is interpreted to dip moderately to the southeast, the true thickness of the mineralization is expected to be approximately |
Additional Data Collected for Future De-risking and Study Work
Approximately 250 kg of whole-core samples were collected for metallurgical test work. Metallurgical test programs are being developed to assess uranium recoveries to advance the evaluation work completed to support the 2018 and 2023 PFS.
Geotechnical logging was completed on all drill holes and hydrogeological information was collected from two of the drill holes which were outfitted with vibrating wire piezometers (VWPs). The information collected from these exercises is expected to increase the understanding of different hydrogeological zones to support future mine-design planning.
This work adds to the extensive database of geological, hydrogeological, geotechnical, and metallurgical data for Gryphon. This site-specific data is expected to be used to validate certain key assumptions in potential future technical studies further evaluating the Gryphon deposit for underground mining.
About Wheeler River
Wheeler River is the largest undeveloped uranium project in the infrastructure-rich eastern portion of the
Based on the respective studies, both deposits have the potential to be competitive with the lowest cost uranium mining operations in the world. Permitting efforts for the planned Phoenix ISR operation commenced in 2019 and several notable milestones were achieved in 2024 with the submission of federal licensing documents and the acceptance of the final form of the project's Environmental Impact Statement by the Province of
About Denison
Denison is a uranium mining, exploration and development company with interests focused in the
Additionally, through its
In 2024, Denison celebrated its 70th year in uranium mining, exploration, and development, which began in 1954 with Denison's first acquisition of mining claims in the
Qualified Persons
The technical information contained in this press release has been reviewed and approved by Chad Sorba, P.Geo., Denison's Vice President Technical Services & Project Evaluation, who is a Qualified Persons in accordance with the requirements of NI 43-101.
Cautionary Statement Regarding Forward-Looking Statements
Certain information contained in this news release constitutes 'forward-looking information', within the meaning of the applicable
In particular, this news release contains forward-looking information pertaining to the following: scope, objectives and interpreted results of the Gryphon delineation program; future plans, including potential future exploration potential and metallurgical test programs; and expectations regarding its joint venture ownership interests and the continuity of its agreements with its partners and third parties. 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.
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. For example, the modelling and assumptions upon which the plans for Wheeler River are based may not be maintained after further work is completed. In addition, Denison may decide or otherwise be required to discontinue testing, evaluation and other work if it is unable to maintain or otherwise secure the necessary resources (such as testing facilities, capital funding, regulatory approvals, etc.). Denison believes that the expectations reflected in this forward-looking information are reasonable but no assurance can be given that these expectations will prove to be accurate and results may differ materially from those anticipated in this forward-looking information. For a discussion in respect of risks and other factors that could influence forward-looking events, please refer to the factors discussed in Denison's Annual Information Form dated March 28, 2025 or subsequent quarterly financial reports under the heading 'Risk Factors'. These factors are not, and should not be construed as being exhaustive.
Accordingly, readers should not place undue reliance on forward-looking statements. The forward-looking information contained in this news release is expressly qualified by this cautionary statement. Any forward-looking information and the assumptions made with respect thereto speaks only as of the date of this news release. Denison does not undertake any obligation to publicly update or revise any forward-looking information after the date of this news release to conform such information to actual results or to changes in Denison's expectations except as otherwise required by applicable legislation
View original content to download multimedia:https://www.prnewswire.com/news-releases/denison-announces-discovery-of-additional-high-grade-mineralization-at-gryphon-and-reports-results-from-successful-delineation-program-302506529.html
SOURCE Denison Mines Corp.
FAQ
What did Denison Mines (DNN) discover in their latest drilling program at Gryphon?
What are the current mineral resources at Denison's Gryphon uranium deposit?
What are the economic metrics for DNN's Gryphon project?
How much drilling did Denison complete in their 2025 Gryphon delineation program?
Where is the Gryphon uranium deposit located?
