Denison Discovers Uranium Mineralization Three Kilometres Northeast of the Huskie Zone, Waterbury Lake Project
Denison Mines Corp.
1100 – 40 University Ave
Toronto, ON M5J 1T1
www.denisonmines.com
@DenisonMinesCo
PRESS RELEASE
DENISON DISCOVERS URANIUM MINERALIZATION
THREE KILOMETRES NORTHEAST OF THE HUSKIE ZONE,
WATERBURY LAKE PROJECT
Toronto, ON – September 17, 2018 Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN:
NYSE American) is pleased to report a new discovery of uranium mineralization on the Company’s
Waterbury Lake project, located in the infrastructu re rich eastern portion of the Athabasca Basin regi on in
northern Saskatchewan. Basement-hosted uranium mine ralization was intersected in two drill holes,
approximately three kilometres northeast of the project’s Huskie zone, returning mineralized assay intervals
of 0.43% U 3O8 over 1.0 metre (including 0.73% U 3O8 over 0.5 metres) in drill hole WAT18-478 and 0.45%
U3O8 over 0.5 metre as well as 0.31% U 3O8 over 0.5 metre and 0.20% U 3O8 over 0.5 metre in drill hole
WAT18-479.
The two drill holes were completed as a fence and were designed to test the intersection of the interpreted
regional Midwest structure with the conductive GB t rend. The mineralization is contained within a 60 t o 80
metre wide package of highly structured and strongly altered graphitic basement rocks, which remains open
along strike to the northwest and southeast. Additional targets exist along the interpreted Midwest structure,
notably to the south at the intersection with the uranium-bearing Oban trend.
Dale Verran, Denison’s Vice President Exploration, commented, “These drill holes were designed as an
initial test of a geological concept – that high-gr ade uranium mineralization occurs at the
intersection of the interpreted regional Midwest st ructure with cross-cutting, graphite-bearing,
structural corridors, as evidenced by the occurrenc e of the J Zone and Roughrider deposits and
the Huskie zone. We are very encouraged by these ea rly results along the GB trend, which has
validated the concept by identifying a mineralized system in proximity to the interpreted structural
intersection. We look forward to following up on these results with further drilling, and the potential
to discover high-grades along strike at GB or along the mineralized Oban trend.”
Further details of the summer 2018 exploration program are provided below and in Figures 1 and 2.
Summer 2018 Exploration Program
The summer 2018 exploration program at Waterbury La ke commenced in late-July and included 3,315
metres of diamond drilling in seven completed holes . The program was focused on drill testing regional
exploration targets related to the interpreted Midwest structure and additional step-out drilling down-dip and
up-dip of the Huskie zone. An initial DCIP resistiv ity survey is planned for mid-September to map the
potential extension of the Midwest structure on to the Waterbury Lake property to the southwest of the
Midwest Main deposit (25.17% Denison-owned) – with the possibility of defining drill targets for futur e
testing. Summer 2018 drill target areas and the location of the DCIP resistivity grid are shown in Figure 1.
Regional Exploration Drilling
A total of four holes were completed on regional targets approximately 2.5 to 3.0 kilometres to the northeast
of the Huskie zone, where the regionally interprete d Midwest structure is projected to intersect the
geologically favourable GB and Oban trends. Figure 2 provides a summary map of the drilling completed
along the GB and Oban trends.
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The regional exploration drilling was highlighted b y two drill holes along the GB trend, completed
approximately 100 metres apart on a north-south fen ce, which both intersected basement-hosted uranium
mineralization. The mineralization occurred as stru cturally-controlled disseminations of uraninite
(pitchblende) associated with massive clay replacement. Highlight intersections included:
• 0.43% U 3O8 over 1.0 metre (including 0.73% U 3O8 over 0.5 metre) from 262.5 to 263.5 metres in
drill hole WAT18-478.
• 0.20% U 3O8 over 0.5 metre from 372.0 to 372.5 metres, 0.45% U 3O8 over 0.5 metre from 410.5 to
411.0 metres and 0.31% U3O8 over 0.5 metre from 420.0 to 420.5 metres in drill hole WAT18-479.
Drill hole WAT18-478 and WAT18-479 were drilled on an azimuth of 0 degrees with dips of -72 degrees
and -74 degrees, respectively. True thickness of th e mineralization is estimated at approximately 70% of
the intersection lengths. The sub-Athabasca unconfo rmity was intersected at approximately 200 vertical ly
below surface in both holes.
The mineralization intersected is open along strike to the northwest and southeast along the GB trend.
Historic drilling was completed during the early 1980’s at a typical spacing of 400 to 600 metres along strike;
however, the drill holes targeted the sub-Athabasca unconformity and did not adequately test the basement
rocks. Apart from the mineralization intersected, multiple geological features were encountered that indicate
potential for high-grade, basement-hosted mineralization, including:
• A broad package of graphitic metasediments, 60 to 80 metres in true width, which has undergone
extensive brittle faulting. The faulting is typical ly coincident with the foliation of the graphitic
metasediments which strike east-west and dip moderately to steeply to the south; with cross-cutting
breccia zones interpreted to represent structures associated with the regionally interpreted Midwest
structure.
• Multiple zones of silica (quartz) flooding, along with bounding granites to the north and south of the
metasedimentary package, which indicate good rheolo gical contrast with the potential to create
space for mineralizing fluids; and
• Strong clay alteration indicating the presence of extensive hydrothermal fluid movement.
In addition, the faulting and alteration identified in the basal sandstone in WAT18-478, along with a possible
unconformity offset to the north, suggest a compelling target at the unconformity at the up-dip projection of
the basement mineralization intersected.
The two regional holes designed to test the Oban trend as part of the summer 2018 program are interpreted
to have tested outside of the intersection of the O ban trend and the Midwest structural zone. A compel ling
basement target still exists on the Oban trend approximately 800 metres to the south of drill holes WAT18-
478 and WAT18-479.
Huskie Zone Drilling
The Huskie zone of high-grade basement-hosted uranium mineralization was discovered by Denison during
the summer of 2017 and is located approximately 1.5 kilometres to the northeast of the property's J Zo ne
uranium deposit. Prior to summer 2018, the completi on of 23 drill holes on an approximate 50 x 50 metr e
spacing allowed for the definition of mineralization over a strike length of approximately 250 metres and dip
length of up to 170 metres. The individual lenses of mineralization vary in interpreted true thickness between
approximately 2 and 7 metres. Highlight drill intersections include:
• 9.1% U 3O8 over 3.7 metres (including 16.8% U 3O8 over 2.0 metres) in drill hole WAT17-446A (see
Denison’s press release dated October 11, 2017); and
• 4.5% U 3O8 over 6.0 metres (including 5.8% U 3O8 over 4.5 metres) in drill hole WAT18-452 (see
Denison’s press release dated April 25, 2018).
The mineralized lenses are interpreted to occur as parallel, stacked lenses, which are conformable to the
foliation and fault planes within the east-west striking graphitic gneiss unit. The drilling to date suggests the
grade, thickness, and number of lenses present is c ontrolled by the presence of northeast striking fau lts
which cross-cut the graphitic gneiss unit. The nort heast striking faults identified at the Huskie zone are
interpreted to be part of the regional Midwest structure.
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A total of three drill holes were completed as part of the summer 2018 program, with targets located b oth
up-dip and down-dip of the known mineralization with a view to test for high-grade extensions related to the
northeast striking, cross-cutting faults.
• Drill hole WAT18-475A , completed as a 50 metre step up-dip of the know m ineralization,
intersected 0.12% eU 3O8 over 1.0 metre from 277.5 metres and 0.15% eU 3O8 over 1.0 metre from
285.5 metres. Due to core loss, the interval is re ported as radiometric equivalent U 3O8 (“eU 3O8”)
derived from a calibrated total gamma downhole probe. The mineralization intersected by WAT18-
475A appeared as disseminations of uraninite (pitch blende) contained within zones of strong clay
replacement surrounded by patches of quartz floodin g. True thickness of the mineralization is
expected to be 75% of the intersection length given the drill hole’s azimuth and dip of 154 degrees
and -81 degrees, respectively.
• The two holes designed to test for extensions down -dip of Huskie, WAT18-473 and WAT18-474 ,
intersected the targeted structure but no significant mineralization was encountered.
Midwest Extension DCIP Resistivity Survey
Current interpretation suggests the Midwest structu re, which hosts the Midwest Main and Midwest A
deposits on the Midwest property (25.17% Denison owned), may extend onto the Waterbury Lake property
to the southwest of the Midwest Main deposit. An in itial DCIP resistivity survey is planned for mid-
September to map the possible extension of the Midw est structure and to define possible drill targets for
future testing.
Waterbury Lake Property
The Waterbury Lake property consists of multiple cl aims covering 40,256 hectares, and is located in th e
infrastructure rich eastern portion of the Athabasc a Basin region in northern Saskatchewan. The prope rty
is jointly owned by Denison (65.45%) and Korea Wate rbury Uranium Limited Partnership (“KWULP”)
(34.55%) through the Waterbury Lake Uranium Limited Partnership (“WLULP”). KWULP consists of a
consortium of investors in which Korea Hydro & Nuclear Power (“KHNP”) holds a majority position. KWULP
has elected not to fund the 2018 exploration progra m and, as a result, will incur dilution of its owne rship
interest in the WLULP. KHNP is also a significant shareholder in Denison, holding 58,284,000 common
shares of Denison, which represents approximately 1 0.42% of the Company’s issued and outstanding
common shares.
Sampling and Assay Procedures
Drill core with anomalous total gamma radioactivity (>500 counts per second using a RS-120 or RS-125
scintillometer) was sampled over 0.5 metre interval s. Sampling is undertaken on site by splitting the core
in half, with one half submitted for analysis and t he other half retained in the core box for future r eference.
Uranium chemical assays are performed by the Saskat chewan Research Council (“SRC”) Geoanalytical
Laboratories located in Saskatoon. Sample preparati on involves crushing and pulverizing core samples t o
90% passing -106 microns. Splits of the resultant p ulps are initially submitted for multi-element ICP- MS
analysis following partial (HNO 3:HCl) and total (HF:HNO 3:HClO 4) digestions. Samples with ≥ 1,000 ppm U
(partial digest) are re-assayed for U 3O8 using an ISO/IEC 17025:2005 accredited method for the
determination of U 3O8 weight %. Pulp splits are digested using aqua-regi a and the solution analyzed for
U3O8 weight % using ICP-OES. In addition to internal ch ecks by SRC Geoanalytical Laboratories, the
Company has rigorous quality assurance and quality control ("QAQC") procedures including the insertion
of standard reference materials, blanks and field d uplicates. The assay data is subject to verificatio n
procedures by qualified persons employed by Denison prior to disclosure. For further details on the assay,
QAQC and data verification procedures please see De nison's Annual Information Form dated March 27,
2018 filed under the Company's profile on SEDAR (www.sedar.com).
Qualified Persons
Dale Verran, MSc, P.Geo, Pr.Sci.Nat., Denison's Vice President, Exploration, who is a Qualified Person in
accordance with the requirements of NI 43-101, has reviewed and approved the technical information
contained in this release.
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About Denison
Denison is a uranium exploration and development company with interests focused in the Athabasca Basin
region of northern Saskatchewan, Canada. In additio n to its 63.3% owned Wheeler River project, which
ranks as the largest undeveloped high-grade uranium project in the infrastructure rich eastern portion of
the Athabasca Basin region, Denison's Athabasca Basin exploration portfolio consists of numerous projects
covering approximately 320,000 hectares. Denison's interests in Athabasca Basin also include a 22.5%
ownership interest in the McClean Lake joint ventur e (“MLJV”), which includes several uranium deposits
and the McClean Lake uranium mill, which is current ly processing ore from the Cigar Lake mine under a
toll milling agreement, plus a 25.17% interest in the Midwest and Midwest A deposits, and a 65.45% interest
in the J Zone deposit and Huskie discovery on the W aterbury Lake property. Each of Midwest, Midwest A,
J Zone and Huskie are located within 20 kilometres of the McClean Lake mill.
Denison is also engaged in mine decommissioning and environmental services through its Denison
Environmental Services division and is the manager of Uranium Participation Corp., a publicly traded
company which invests in uranium oxide and uranium hexafluoride.
For more information, please contact
David Cates (416) 979-1991 ext. 362
President and Chief Executive Officer
Sophia Shane (604) 689-7842
Investor Relations
Follow Denison on Twitter @DenisonMinesCo
Cautionary Statement Regarding Forward-Looking Statements
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 an d similar Canadian legislation concerning the busin ess, operations and financial
performance and condition of Denison.
Generally, these forward-looking statements can be identified by the use of forward-looking terminolog y such as "plans", "expects",
"budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "believes", or the negatives and/or variations of such words and
phrases, or state that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur", "be achieved" or "has
the potential to". In particular, this press release contains forward-looking information pertaining to the following: exploration (including
drilling) and evaluation interpretations, activities, plans and objectives, and Denison’s percentage in its properties and its plans and
agreements with its joint venture partners, as applicable.
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 forward-looking statements. 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 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 27, 2018 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 press 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 press release. 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 .
This document contains certain information derived from third-party publications and reports, includin g estimates of resources and
mineralization of the Roughrider deposit, which Denison believes are reliable but have not been independently verified by Denison.
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Figure 1: Summary plan map of the summer 2018 exploration program related to the Midwest
regional structure.
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Figure 2: Summary plan map of the GB and Oban trends.