Denison Announces Completion of Isr Field Program and Initiation of Exploration Program at Wheeler River
Denison Mines Corp.
1100 – 40 University Ave
Toronto, ON M5J 1T1
www.denisonmines.com
PRESS RELEASE
DENISON ANNOUNCES COMPLETION OF ISR FIELD PROGRAM AND
INITIATION OF EXPLORATION PROGRAM AT WHEELER RIVER
Toronto, ON – Oct 28, 2020. Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN: NYSE
American) is pleased to announce that field activi ties at Denison’s 90% owned Wheeler River Uranium
Project (“Wheeler River”) have safely and successfully transitioned from the In-Situ Recovery (“ISR”) field
program at the high-grade Phoenix uranium deposit (“Phoenix”), which was initiated in July (see press
release dated July 27, 2020), to a ~12,000 metre explor ation drilling program designed to test initially for
extensions to known mineralization at Phoenix and then advance to regional targets for the discovery of
satellite uranium deposits potentially amenable to ISR mining.
David Cates, Denison’s President & CEO, commented “Having recently raised US$19 million through a
well supported public offering, Denison remains debt free and is well funded with over CAD$29 million in
cash. We are now turning our attention to finalizing our plans for 2021 and beyond, as well as completing
our planned activities in 2020 – including an exciti ng exploration program at Wheeler River and the
Preliminary Economic Assessment (‘PEA’) planned for the J Zone deposit on the Waterbury Lake property.
I’m proud of the effort that our team has put in to make the most of 2020, despite a temporary suspension
of the formal part of the Wheeler River Environmental Assessment (‘EA’) – carrying out important scopes
of work, including the 2020 ISR field program, in order for the company to be poised for a strong future re-
start to the formal EA process.”
ISR Field Program
The ISR field work completed in 2020 (the “2020 Field Program”) was designed with the primary objective
of building additional confidence in the results of an independent hydrogeologic “Proof of Concept” model
developed for Phoenix by Petrotek Corporation (“Petro tek”) for the application of the ISR mining method
(see press release dated J une 4, 2020). Taken together with the installation of additional environmental
monitoring wells, the data collected during the 2020 Field Program is expected to support the design and
permitting of further field tests to be incorporated into a future Feasibility Study (“FS”).
David Bronkhorst, Denison’s Vice President Operations, commented, “While the formal EA process for
Wheeler River was suspended in March 2020, in response to the COVID-19 pandemic, Denison’s Wheeler
River project team has been busy advancing certain sc opes of work during the year – including the 2020
Field Program. Our activities in 2020 have been designed to ensure the EA and future FS support activities
can advance as quickly as possible, and with minimized impact to the Project schedule, following a decision
to resume the formal EA process.
The 2020 ISR Field Program at Phoenix was completed safely and successfully, despite the disruptions
related to COVID-19 – resulting in the collection of an extensive hydrogeological data set based on
seventeen additional pump and injection tests, permea meter test work and groundwater sampling. This
work is expected to further validate and increase our confidence in the previously announced independent
‘proof of concept’ model developed by Petrotek.”
Key elements of the completed 2020 Field Program included:
Hydrogeological test work
o 17 pump and injection tests were completed between Test Area 1 and Tests Area 2 at
Phoenix Zone A (see Figure 1 for Wheeler River location, and Figure 2 for Phoenix);
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o Data collected from these te sts will supplement the extensive dataset acquired as part of
the 2019 ISR field testing program (see press release dated December 18, 2019), and is
expected to provide additional insight into individual well capacities and the overall
hydrogeological network of the deposit areas.
Permeameter analysis
o Over 1,000 additional drill core samples were collected from historic holes, dried, and
analyzed for permeability and porosity;
o Samples were selected to refine our understanding of the mineralized hydrogeologic
horizons, including the low permeability basement rocks and the overlying sandstone.
Rock mechanics
o Mineralized core samples were collected and shipped to SNC Lavalin (Saskatoon) for
rock mechanics tests, including tensile strength and uniaxial compressive strength;
o The samples targeted various previously identified hydrogeologic units, including the
Upper Clay Zone, Lower Clay Zone and High-Grade Friable Zone;
o Results from these tests will be utilized to better define the design of certain permeability
enhancement techniques for subsequent field programs.
Groundwater sampling
o Groundwater samples were collected from ei ght different environmental monitoring wells
in the Phoenix deposit area;
o Sampling occurred at several horizons within each well – including the horizons above,
below, and within the Phoenix ore body;
o Samples have been submitted to the Saskatchewan Research Council (“SRC”) for
analysis. Once received, data from these samples will be utilized to support the design
and permitting of additional field tests expected to be incorporated into a future FS.
Installation of additional environmental monitoring wells
o Five additional monitoring wells were installed in two clusters, located approximately 500
metres northeast of Phoenix, and 750 metres southeast of Phoenix (see Figure 2);
o The additional monitoring wells will allow for the collection of groundwater flow information
at locations further away from the Phoeni x deposit than had been previously studied,
providing additional data for the site groundwater model – which will allow for long-term
monitoring and the modelling of ground water impacts through construction, operations
and decommissioning, each of which will be an important element of the effects
assessments in an Environmental Impact Statement (“EIS”).
Exploration Drilling Program
The 2020 exploration drilling program at Wheeler River commenced late in the third quarter. The program
is expected to include ~12,000 metres of diamond drilling, planned in 27-30 drill holes. The drill program is
designed to be executed in several phases, with an initial focus on the area proximal to Phoenix where
further exploration and delineation drilling is warranted to identify potential additional mineralization that
could be included as part of a future FS. Of particular focus is the area around Zone B, where previous
exploration results suggest that the potential for additional mineralization rema ins outside of the current
extents of the estimated mineral resource. The pr ogram has also been designed to test for additional
mineralization at Phoenix Zone C (where there are previous mineralized intercepts, but where no mineral
resource is currently estimated) and to explore regio nal target areas elsewhere on the property with the
potential to produce a discovery that could become a satellite deposit potentially amenable to ISR mining.
As of October 27 th, the Company has completed approximately 5,460 metres of drilling, representing
roughly 44% of the total planned for the 2020 exploration program. A total of 12 holes have been completed
to target depth, as well as three holes that were abandoned due to either excessive deviation or drilling
difficulties. All drill holes completed to date hav e been located outside of the previously delineated
mineralized zones for Phoenix, with results highlighted by the following mineralized intercepts:
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WR-765D1 (Phoenix Zone B) intersected uranium mi neralization straddling the unconformity
contact, grading 0.39% eU 3O8 over 3.8 metres (from 399.85 to 403.65 metres) – approximately
15.0 metres east of WR-333 (which previously intersected 14.6% U3O8 over 6.0 metres); and
WR-771 (Phoenix Zone C) encountered uranium mineralization approximately 4 metres below the
unconformity contact, grading 0.86% eU 3O8 over 1.2 metres (from 375.15 to 376.35 metres) –
approximately 28.8 metres to the southwest of WR-368 (which previously intersected 1.59% U3O8
over 2.0 metres)
The remaining targets at Phoenix will be re-prioritized by incorporating the results of the recently completed
drill holes. Dependent on results, exploration drilling pr oximal to Phoenix is expected to be completed in
early to mid-November, with the expectation that the focus of the exploration drill program will shift to
regional drill targets that have been prioritized based on their potential to result in the discovery of satellite
uranium deposits that may be amenable to ISR mining.
The Company reports results as prelimi nary radiometric equivalent grades ("eU 3O8"), derived from a
calibrated downhole total gamma probe, during acti ve exploration programs and subsequently reports
definitive assay grades following sampling and chemical analysis of the mineralized drill core. Radiometric
equivalent probe results are subject to verification pr ocedures by qualified persons employed by Denison
prior to disclosure. For further details on the total gamma downhole probe methods employed by Denison,
QAQC procedures and data verification procedures please see Denison's Annual Information Form dated
March 13, 2020 filed under the Company's profile on SEDAR (www.sedar.com).
About Wheeler River
Wheeler River is the largest undeveloped uranium projec t in the infrastructure rich eastern portion of the
Athabasca Basin region, in northern Saskatchewan – including combined Indicated Mineral Resources of
132.1 million pounds U3O8 (1,809,000 tonnes at an average grade of 3.3% U 3O8), plus combined Inferred
Mineral Resources of 3.0 million pounds U 3O8 (82,000 tonnes at an average grade of 1.7% U 3O8). The
project is host to the high-grade Phoenix and Gryphon uranium deposits, discovered by Denison in 2008
and 2014, respectively, and is a joint venture between Denison (90% and operator) and JCU (Canada)
Exploration Company Limited (10%).
A Pre-feasibility Study (“PFS”) was completed for Wh eeler River in late 2018, considering the potential
economic merit of developing the Phoenix deposit as an ISR operation and the Gryphon deposit as a
conventional underground mining operation. Taken toget her, the project is estimated to have mine
production of 109.4 million pounds U 3O8 over a 14-year mine life, with a base case pre-tax NPV of $1.31
billion (8% discount rate), Internal Rate of Return ("IRR") of 38.7%, and initial pre-production capital
expenditures of $322.5 million. The Phoenix ISR operati on is estimated to have a stand-alone base case
pre-tax NPV of $930.4 million (8% discount rate), IRR of 43.3%, initial pre-production capital expenditures
of $322.5 million, and industry-leading average operating costs of US$3.33/lb U3O8. The PFS is prepared
on a project (100% ownership) and pre-tax basis, as each of the partners to the Wheeler River Joint Venture
are subject to different tax and other obligations.
Further details regarding the PFS, including additional scientific and technical information, as well as after-
tax results attributable to Denison's ownership intere st, are described in greater detail in the NI 43-101
Technical Report titled "Pre-feasibility Study for the Wheeler River Uranium Project, Saskatchewan,
Canada" dated October 30, 2018 with an effective date of September 24, 2018. A copy of this report is
available on Denison's website and under its prof ile on SEDAR at www.sedar.com and on EDGAR at
www.sec.gov/edgar.shtml.
Given recent social, financial and market disruptions, Denison has suspended certain activities at Wheeler
River, including the formal EA process, which is on t he critical path to achieving the project development
schedule outlined in the PFS. The Company is not curr ently able to estimate the impact to the project
development schedule outlined in the PFS, and users are cautioned against relying on the estimates
provided therein regarding the start of pre-production activities in 2021 and first production in 2024.
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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 addition to the Wheeler River project, Denison's Athabasca
Basin exploration portfolio consists of numerous projects covering over 250,000 hectares. Denison's
interests in the Athabasca Basin also include a 22.5% ownership interest in the McClean Lake joint venture
("MLJV"), which includes several uranium deposits and the McClean Lake uranium mill, which is currently
processing ore from the Cigar Lake mine under a to ll milling agreement, plus a 25.17% interest in the
Midwest and Midwest A deposits, and a 66.71% interest in the J Zone and Huskie deposits on the
Waterbury Lake property. Each of Midwest, Midwest A, J Zone and Huskie are located within 20 kilometres
of the McClean Lake mill.
Denison is engaged in mine decommissioning and environmental services through its Closed Mines group
(formerly Denison Environmental Services), which manages Denison's Elliot Lake reclamation projects and
provides post-closure mine care and maintenance services to a variety of industry and government clients.
Denison is also the manager of Uranium Participat ion 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
Qualified Persons
The technical information contained in this release related to the 2020 ISR Field Program and the Wheeler
River PFS has been reviewed and approved by Mr. David Bronkhorst, P.Eng, Denison's Vice President,
Operations, who is a Qualified Person in accordance with the requirements of NI 43-101.
The technical information contained in this release related to the Exploration Drilling Program has been
reviewed and approved by Mr. Andrew Yackulic, P. Geo, Denison's Director, Exploration, who is a Qualified
Person 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 United
States and Canadian legislation concerning the business, operations and financial performance and condition of Denison.
Generally, these forward-looking statements c an be identified by the use of forward-look ing terminology 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 news release contains forward-looking information pertaining to the following: the results of the 2019 Field Test and
2020 Field Program, including the hydrogeologi c model, and their underlying assumptions and interpretations; the 2020 explorati on
drilling program, including its intended scope and timing, objectives and interpretations; the Company’s intentions with respect to the
Waterbury PEA; the current and continued use and availability of th ird party technologies for testing; the results of the PFS a nd
expectations with respect thereto; development and expansion plans and objectives, including the Company’s intentions with respect
to the resumption of the EA and feasibility study support activities and the potential impacts to the project schedule plans for a feasibility
study; the duration and scope of impacts of the COVID-19 pan demic and affiliated operational adjustments; and expectations
regarding its joint venture ownership interests and the continuity of its agreements with its partners.
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 c ause the actual results, level of activi ty,
performance or achievements of Denison to be materially different from those expre ssed or implied by such forward-looking
statements. For example, the results of the 2020 exploration drilling program, 2019 Field Test, hydrogeologic model and/or 2020 Field
Program discussed herein may not be maintained after further te sting or be representative of ac tual conditions within the Phoen ix
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deposit. In addition, Denison may decide or otherwise be required to discontinue the 2020 Field Program, exploration drilling program
or other testing, evaluation and development work at Wheeler River if it is unable to maintain or otherwise secure the necessar y
resources (such as testing facilities, capital funding, regulatory approvals, etc.) or operations are otherwise affected by COVID-19 and
its potentially far-reaching impacts. 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 res pect of risks and other factors that could influence forward-lookin g events,
please refer to the factors discussed in Denison’s Annual Information Form dated March 13, 20 20 or subsequent quarterly financi al
reports under the heading ‘Risk Factors’. These factors are not, and should not be construed as being exhaustive.
Accordingly, readers should not place undue re liance on forward-looking statements. The forward-looking information contained i n
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 rel ease to conform such information to actual results or to changes in
Denison's expectations except as otherwise required by applicable legislation.
Cautionary Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Mineral Resources
and Probable Mineral Reserves: This press release may use the terms 'measured', 'indicated' and 'inferred' mineral resources.
United States investors are advised that while such terms have been prepared in accordance with the definition standards on mineral
reserves of the Canadian Institute of Mining, Metallurgy and Pe troleum referred to in Canadian National Instrument 43-101 Miner al
Disclosure Standards ('NI 43-101' ) and are recognized and required by Canadian regul ations, these terms are not defined under
Industry Guide 7 under the United States Securities Act and, unt il recently, have not been permitted to be used in reports and
registration statements filed with the United States Securities and Exchange Commission ('SEC'). '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 al l or any
part of an inferred mineral resource will ever be upgraded to a higher category. Under Canadian rules, estimates of inferred mi neral
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 investor s are
also cautioned not to assume that all or any part of an inferr ed mineral resource exists, or is economically or legally mineabl e. In
addition, the terms "mineral reserve", "pro ven mineral reserve" and "probable mineral reserve" for the purposes of NI 43-101 di ffer
from the definitions and allowable usage in Industry Guide 7. Effective February 2019, the SEC adopted amendments to its disclosure
rules to modernize the mineral property di sclosure requirements for issuers whose secu rities are registered with the SEC under the
Exchange Act and as a result, the SEC now re cognizes estimates of "measured mineral re sources", "indicated mineral resources"
and "inferred mineral resources". In addition, the SEC has amended its definitions of "proven mineral reserves" and "probable mineral
reserves" to be "substantially similar" to the corresponding definitions under the CI M Standards, as required under NI 43-101.
However, information regarding mineral res ources or mineral reserves in Denison's disclosure may not be comparable to similar
information made public by United States companies.
Figure 1: Location Map of Wheeler River Showing Existing Regional Infrastructure.
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Figure 2: Plan Map of Phoenix Showing Location of 2020 ISR Field Test Work