Denison Announces 2019 Exploration Program Focused ON High Potential Properties

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Denison Mines Corp. 

1100 – 40 University Ave 

Toronto, ON  M5J 1T1 

www.denisonmines.com 

@DenisonMinesCo 

PRESS RELEASE

DENISON ANNOUNCES 2019 EXPLORATION PROGRAM FOCUSED ON

HIGH POTENTIAL PROPERTIES

Toronto, ON – January 9, 2019 Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN:

NYSE American) is pleased to announ ce the details of a disciplined CAD$6 million (Denison’s share)

exploration program planned for 2019. Exploration activities will be focused on diamond drill testing of targets

on the Company’s Wheeler River, Waterbury Lake, and Hook-Carter properties – each of which are located

in the Athabasca Basin in northern Saskatchewan and are considered to have high potential for a near-term

discovery of uranium mineralization.

2019 Exploration Program Highlights

 Wheeler River: As announced in Denison’s press release dated December 18, 2018, exploration

plans for Wheeler River in 2019 include a diamond drilling program of approximately 13,500 metres

in 23 holes. The program is designed to evaluate high priority regional target areas by focusing on

initial testing of targets at the sub-Athabasca un conformity – which could lead to the discovery of

further uranium deposits that may be amenable to t he use of the low-cost In-Situ Recovery (“ISR”)

mining method. Denison recently selected the ISR mining method for application at Wheeler River’s

high-grade Phoenix deposit, with an estimated operating cost of approximately US$3.33/lb U3O8 (see

Denison’s press releases dated September 24 and October 30, 2018).

 Waterbury Lake: The Company’s geological interpretation indicates that the regional Midwest

structure not only controls the location of the Midwest deposits on the Midwest property (25.17%

Denison owned) but also the J Zone and Huski e deposits on the Waterbury Lake property. The

program planned for 2019 includes approximately 7,300 metres of diamond drilling in 18 holes and

will focus on testing additional high-priority target areas related to the interpreted Midwest structure

– including the follow-up of basement-hosted mineralization, discovered during the summer of 2018,

where the Midwest structure is interpreted to intersect the GB Trend (see Denison’s press release

dated September 17, 2018).

 Hook-Carter: An initial group of reconnaissance drill holes, completed during 2018 along the

Patterson Lake Corridor (“PLC”), at Hook-Carter encountered favourable lithologies, structures and

hydrothermal alteration analogous to the geological settings observed for the Arrow (Nexgen Energy

Ltd.) and Triple R (Fission Uranium Corp.) deposits located 12 and 20 kilometres southwest along

strike, respectively. A diamond drilling program, including approximately 3,900 metres in six holes,

is planned for 2019 to continue to test high priority geophysical targets, particularly along the eastern

edge of the PLC, where geochemical analysis of the 2018 drilling results has returned encouraging

results.

David Cates, President and CEO of Denison, commented “With our focus turning to the advancement of

our flagship Wheeler River project through the Environmental Assessment process, our strategy

continues to involve exploration of our portfolio of high-priority properties – where we have the

potential to deliver Denison’s next high-grade Athabasca uranium discovery. Our Saskatoon-based

exploration team has a track-record of discovery success and has developed a 2019 exploration

program that is disciplined and includes a compelling set of drill targets – each with the potential to

deliver exciting and meaningful exploration results throughout the year.”

Figure 1 provides a location map of Denison’s Athabasca exploration properties as at December 31, 2018.

Exploration targets or target areas, planned for drill te sting in 2019, for the Wheeler River, Waterbury Lake

and Hook-Carter properties are shown in Figures 2, 3 and 4, respectively.

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Wheeler River

Following the completion of a Pre-Feasibility study (“PFS”) in Q3 2018 (see Denison’s press releases dated

September 24 and October 30, 2018), and given the highly encouraging results from the proposed Phoenix

ISR operation, the planned 2019 exploration drilling progr am will be focused on initial testing of regional

targets at the sub-Athabasca unconformity, with the potential to discover additional ISR amenable uranium

deposits. Potential for basement hosted uranium mineralization will not be ignored where opportunities also

exist to evaluate prospective basement targets. High priority regional target areas planned for testing in 2019

include K West, M Zone, K South, Gryphon South, Q S outh (East), and O Zone, each of which is shown in

Figure 2.

The 2019 Wheeler River exploratio n budget totals CAD$3.2 million (100% basis) wh ich includes

approximately 13,500 metres of diamond drilling in 23 holes. Drilling activities are scheduled to commence

in early January for the winter season utilizing one drill rig, follow ed by a results-driven summer drilling

program - providing a staged-approach to target evaluation. The Wheeler River project is owned by Denison

(90% and operator) and JCU (Canada) Exploration Company Limited (10%). Accordingly, Denison will fund

90% of project expenditures in 2019.

Waterbury Lake

Following on from the Company’s discovery of the Huskie deposit in 2017, a revised geological interpretation

of the regional Midwest structure has led to the identi fication of several high priority target areas on the

eastern portion of the Waterbury Lake property (Figur e 3). The target areas primarily occur where the

Midwest structure is interpreted to occur within, or intersect with, graphite-bearing basement lithologies. Initial

testing of these target areas was undertaken during summer 2018 with four drill holes, two of which returned

multiple basement uranium intercepts (up to 0.43% U 3O8 over 1.0 metre) from the GB Trend within a 60 to

80 metre wide package of highly structured and strongl y altered graphitic basement rocks (see Denison’s

press release dated September 17, 2018).

The 2019 exploration program is focused on continued drill testing of high priority target areas associated

with the regional Midwest Structure, including follow-up on the GB Trend, and initial testing of the Oban South

Trend and Midwest Extension area (Figure 3). Within t he Midwest Extension area, to the southwest of the

Midwest deposits, drill targets have been identified from a DCIP resistivity completed during the fall of 2018.

Additional target areas may include GB Northeast (ele ctromagnetic target) and the Waterbury East claim

(follow-up of an historic mineralized intersection of 0.32% U3O8 over 1.1 metres in drill hole WAT07-008).

The 2019 Waterbury Lake budget totals CAD$1.8 m illion which includes approximately 7,300 metres of

diamond drilling in 18 holes. The results-driven drilling program is expected to be completed during the winter

season utilizing one drill rig with a planned start date in mid-January.

The Waterbury Lake property is owned by Deniso n and Korea Waterbury Uranium Limited Partnership

(“KWULP”). Denison is the operator of the project, holding a 65.92% ownership interest (KWULP 34.06%)

as of October 31, 2018. The 2019 exploration program will be funded by Denison, as KWULP has elected to

continue to dilute their interest in the project.

Hook-Carter

A maiden drilling program was completed by Denison in 2018 as part of the first phase of exploration planned

to test, at a reconnaissance level, 7.5 of the 15 kilometr es of interpreted strike length of the Patterson Lake

Corridor (“PLC”) at Hook-Carter. The 2018 drill pr ogram included nine completed drill holes, which

successfully identified multiple prospective trends with geological features commonly associated with

Athabasca Basin unconformity-related uranium deposits – including hydrothermal alteration in both the

sandstone and the basement lithologies associated with graphitic basement structures.

A diamond drilling program, consisting of approximately 3,900 metres in 6 holes, is planned for winter 2019

with a total budget of CAD$1.4 million. The program is designed to complete the first phase of reconnaissance

exploration along 7.5 kilometres of the PLC. The drill targets include both electromagnetic (“EM”) and

resistivity targets from the 2017 grou nd surveys, which are coincident with positive exploration vectors

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identified from a detailed geochemical and clay analysis of the 2018 drilling results. Completion of these

targets, in addition to the targets drilled in 2018, will result in a widely-spaced drill hole coverage, with an

approximate 1,200 metre spacing along strike, on the southwestern portion of the PLC at Hook-Carter –

providing a first pass evaluation and a valuable regional dataset to enable prioritization of follow-up drilling.

Exploration targets planned for drill testing in 2019 are shown in Figure 4.

The Hook-Carter property is highlighted by 15 kilometres of strike potential along the prolific Patterson Lake

Corridor – host to the Triple R deposit (Fission Ur anium Corp.), Arrow deposit (NexGen Energy Ltd.), and

Spitfire discovery (Purepoint Uranium Group Inc., Cameco Corp., and Orano Canada Inc.), which occur within

8 to 20 kilometres of the property. The property is significantly underexplored compared to other properties

along this trend and covers significant portions of the Derkson and Carter Corridors, which provide additional

target areas. The Hook-Carter property consists of 80 mineral claims, covering approximately 24,229

hectares, and is owned 80% by Denison and 20% by ALX Uranium Corp. (“ALX”). The 2019 exploration

program will be funded by Denison, as part of its agreement to fund ALX's share of the first CAD$12 million

in expenditures on the project (see Denison’s Press Releases dated October 13 and November 7, 2016).

Qualified Persons

Dale Verran, MSc, P.Geo, Pr.Sci.Na t., Denison's Vice President, Explorat ion, 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.

The disclosure of the results of the PFS contained in this news release, including the mineral reserves, was

reviewed and approved by Peter Longo, P. Eng, MBA, PMP, Denison’s Vice-President, Project Development,

who is a Qualified Person in accordance with the requirements of NI 43-101.

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 its 90% 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 expl oration portfolio consists of numerous projects

covering approximately 320,000 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 pr ocessing 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 65.92% 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 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

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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 and similar Canadian legislation concerning the business, operations and financial performance

and condition of Denison.

Generally, these forward-looking statements can be identified by the use of forward-looking 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 press release contains forward-lookin g information pertaining to the following: exploration (including drilling) and

evaluation interpretations, activities, plans and objectives; the results of the PFS and plans and expectations with respect th ereto; and

Denison’s percentage in its properties and its plans and agreements with its joint venture partners, as applicable. 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 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 forwar d-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.

Cautionary Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Mineral Resources: This

press release may use the terms “measured”, “indicated” and “inferred” mineral resources. United States investors are advised that while

such terms are recognized and required by Canadian regulations, t he United States Securities and Exchange Commission does not

recognize them. “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 all or any part of an inferred mi neral resource will ever be upgraded to a higher category. Under

Canadian rules, estimates of inferred mineral resources may not form the basis of feasibility or other economic studies. Unite d 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 investors are also cautioned not to assume that all or any part of an inferred mineral resource exists, or is

economically or legally mineable.

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Figure 1: Location map of Denison’s Athabasca exploration properties as at December 31, 2018,

with the Wheeler River, Waterbury Lake and Hook-Carter properties shown in bold outline.

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Figure

Figure 2: Location of the high priority regional target areas planned for exploration drill testing in 2019,

shown on the Wheeler River basement geology map.

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Figure 3: Location of the Waterbury Lake 2019 drill target areas in relation to

the interpreted regional Midwest structure.

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Figure 4: Location of the Hook-Carter 2019 drill targets.