Denison Mines : PDAC Corp. Investor Forum – March 2020

Uranium Development & Exploration

The Athabasca Basin, Northern Saskatchewan

March 2020 | PDAC Corporate Presentation Forum for Investors - Uranium

Cautionary Statements & References

This presentation and the information contained herein is designed to help you understand management's current views, and may not be appropriate for other purposes. This presentation contains information relating to other companies and provincial infrastructure, and the plans and availability thereof, derived from third-party publications and reports which Denison believes are reliable but have not been independently verified by the Company.

Certain information contained in this presentation 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, theseforward-lookingstatements can be identified by the use offorward-lookingterminology 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 presentation containsforward-lookinginformation pertaining to the results of, and estimates, assumptions and projections provided in, the PFS, including future development methods and plans, market prices, costs and capital expenditures; assumptions regarding Denison's ability to obtain all necessary regulatory approvals to commence development; Denison's percentage interest in its projects and its agreements with its joint venture partners; and the availability of services to be provided by third parties. Statements relating to "mineral resources" are deemed to beforward-lookinginformation, as they involve the implied assessment, based on certain estimates and assumptions that the 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. Denison faces certain risks, including the inability to permit or develop the project as currently planned, the unpredictability of market prices, the use of mining methods which are novel and untested in the Athabasca basin, events that could materially increase costs, changes in the regulatory environment governing the project lands, and unanticipated claims against title and rights to the project. Denison believes that the expectations reflected in thisforward-lookinginformation are reasonable but there can be no assurance that such statements 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 influenceforward-lookingevents, please refer to the "Risk Factors" in Denison's Annual Information Form dated March 27, 2018 available under its profile at www.sedar.com and its Form40-Favailable at www.sec.gov/edgar.shtml. These factors are not, and should not be construed as being exhaustive.

Readers should not place undue reliance onforward-lookingstatements. The forward-looking information contained in this presentation 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 the September 24, 2018 press release to which this presentation relates. Denison does not undertake any obligation to publicly update or revise any forward-looking information after such date to conform such information to actual results or to changes in its expectations except as otherwise required by applicable legislation.

Cautionary Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Mineral Resources: This presentation 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, the 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 mineral 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.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 investors are also cautioned not to assume that all or any part of an inferred mineral resource exists, or is economically or legally mineable.

Qualified Persons

The disclosure of a scientific or technical nature within this presentation, including the disclosure of mineral resources and reserves and PFS results, was reviewed and approved by 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.

Wheeler River Technical Reports

For further details regarding the Wheeler River project, please refer to the Company's press release dated September 24, 2018 and the technical report titled "Prefeasibility Study for the Wheeler River Uranium Project, Saskatchewan, Canada" with an effective date of September 24, 2018. For a description of the data verification, assay procedures and the quality assurance program and quality control measures applied by Denison, please see Denison's Annual Information Form dated March 12, 2019. Copies of the foregoing are available on Denison's website and under its profile on SEDAR at www.sedar.com and on EDGAR at www.sec.gov/edgar.shtml.

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Diversified Athabasca Basin

Asset Base with Superior

Development Leverage

Strategic Asset Portfolio:

• 90% interest in FlagshipWheeler Riverproject
• • Development stage project
  • Largest undeveloped uranium project in the infrastructure rich eastern Athabasca Basin
  • Environmental Assessment ("EA") initiated
• 22.5% interest inMcClean Lake Uranium Mill
• • Processing +12% of global uranium production
  • Excess licensed capacity
• Additional leverage to the uranium price from interests in undeveloped uranium resources atMcClean Lake, Midwest,and Waterbury Lake
• ~280,000 hectaresof prospective exploration ground in the Athabasca Basin
• Internal sources ofCash Flow
• • Uranium Participation Corp.(TSX-U)
  • Closed mine care & maintenance (formerly Denison Environmental Services)

3

22.5% Denison owned McClean Lake uranium mill

~280,000 Hectares of Prospective Exploration & Development Ground Focused in the Infrastructure Rich Eastern Athabasca Basin

Denison Land Position

as of June 30, 2019

Orano

Waterbury

(Denison 66.6%)

McClean Lake Mill

(Denison 22.5%)

Hook-Carter

(Denison 80%)

Cigar Lake Mine

Rabbit Lake Mill

McArthur River Mine

Wheeler River (Denison 90%)

Key Lake Mine & Mill

All Season	Provincial	4
Highway / Haul Road	Power Grid

Flagship Wheeler River

Development Project(1)

90% Denison Owned (10% JCU):

• Host to twohigh-grade uranium deposits
• NI43-101 compliant Pre-Feasibility Study ("PFS") considers staged development plan
• Phoenixestimated to potentially have lowest costs of any undeveloped uranium deposit
• • In-SituRecovery ("ISR") mining method
  • On-siteprocessing to finished yellow cake
  • Initiation of EA approved by Board & JV
  • All-incosts of US$8.90/lb U3O8
  • Operating costs ofUS$3.33/lb U3O8
• Gryphoncontributes additional low-cost pounds
• • Conventional underground mining approach
  • Assumestoll-milling at McClean Lake mill
  • All-incost of US$22.82/lb U3O8
  • Operating costs ofUS$11.70/lb U3O8
• Combined109.4Mlbs U3O8Probable Reserves
• Combined14year mine life
• Initial CAPEX (Phoenix) of$322.5M(100%)

5

NOTES:(1) Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River Uranium Project, Saskatchewan, Canada" dated September 24, 2018;

ISR test well head installed at Wheeler River Phoenix Deposit, Summer 2019

Wheeler River PFS:

Potential to be one of the lowest all-in cost uranium mining operations

Sample of Global Production Costs(1)(2)

Planned and Producing Operations (with Mining Method)

$50.00

8

O

$45.00

3

U

$40.00

USD$/lb

$35.00

$30.00

-

Costs

$25.00

US$22.82

$20.00

Full

$15.00

/

US$8.90

-in

$10.00

All

$5.00

ISR

ISR

ISR

ISR

UG

ISR

UG

UG

UG

UG

ISR

UG

ISR

OP

$0.00

Denison/Canada

Canada

Kazakhstan

Australia

United States

Africa

NOTES:(1) Chart data, including all-in costs, have been derived from UxC's estimates of Worldwide Production Costs as of August 2019.	6
(2) For Phoenix and Gryphon, refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River
Uranium Project, Saskatchewan, Canada" dated September 24, 2018.

Wheeler River PFS:

Staged development plan with combined 14-year mine life(1)

Million Pounds U O Per Annum 3 8

16

14

12

10

8

6

4

2

0

	Phoenix: 10-year mine life			Phoenix		Gryphon
	@ 6M lbs U3O8per year
		Gryphon: potential second
Environmental		operation. Additional
Assessment /		production to be developed
Permitting &		to match market needs
Feasibility Study

2021 2022 2023 2024 202520262027 2028 2029 2030

2031 203220332034

2035 20362037

NOTES:(1) Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report	7
for the Wheeler River Uranium Project, Saskatchewan, Canada" dated September 24, 2018.

Wheeler River PFS:

Uranium price assumptions, commercial strategy, and sensitivities

	PFS Pre-Tax NPV8%(100% Basis)
	3000
	2500
millions$	2000
1500	$1.41B	$2.59B
	1000	PFS
	$1.31B
	500	$0.5B
		PEA
	0
	Base Case	PEA Ref. Case	High Case
Assumptions / Results(1)	Base Case	PEA Ref. Case	High Case
Uranium selling price	As above	US$44/lb U3O8	US$65/lb U3O8
Pre-tax NPV8%(2)(100% Basis)	$1.31 billion	$1.41 billion	$2.59 billion
Pre-tax IRR(2)	38.7%	47.4%	67.4%
Pre-tax payback period(3)	~24 months	~ 15 months	~ 11 months

Base Case Price Assumptions Reflect Commercial Strategy:

• Phoenix Operation:
• • Lowall-in cost per lb U3O8suggests contract "base-loading" not required
  • Uranium selling price based on UxC
    Spot price forecast (Q3'2018 UMO "Composite Midpoint" scenario)
  • ~US$29/lb U3O8to US$45/lb U3O8
  • Stated in "constant" 2018 dollars
• Gryphon Operation:
• • US$50/lb U3O8fixed price
  • Market support expected to be trigger for development

Comparison to 2016 Preliminary Economic Assessment ("PEA"):

• 2016 PEA providedpre-tax project NPV8%of $513 million at fixed uranium price of US$44/lb U3O8
• PFS equivalent represents +275% ofpre-taxproject NPV from PEA

NOTES:(1) Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River Uranium Project, Saskatchewan, Canada"

dated September 24, 2018; (2) NPV and IRR are calculated to the start of pre-production activities for the applicable operation; (3) Payback period is stated as 8number of years to pay-back from the start of commercial production.

Phoenix Deposit:

Combining the world's lowest-cost uranium mining method with the world's highest-grade undeveloped uranium deposit

9

ISR field testing at Wheeler River Phoenix Deposit, Summer 2019

ISR test well at Wheeler River

Phoenix Deposit, Summer 2019

10

CSW installed at Wheeler River Phoenix Deposit, Summer 2019

Phoenix Deposit:

Combining the world's lowest-cost uranium mining method with the world's highest-grade undeveloped uranium deposit

11

Installation of Commercial Scale Wells as part of ISR Field test work at Wheeler River Phoenix Deposit, Summer 2019

Phoenix Geology: Unique uranium deposit

with exceptionally high grades

Highlights(1):

• Mineralization is situated at or immediately above the unconformity("UC")
• Two distinct zones - Phoenix A + B
• Approximately 400m below surface
• World'shighest-grade undeveloped uranium deposit
• 70.2 million pounds U3O8@ 19.14% U3O8Indicated mineral resources (166,400 tonnes)(2)
• • Zone AHigh-Grade Core contains an
    estimated59.9 M lbs U3O8@ 43.2% U3O8(62,900 tonnes)
  • Cut-offgrade of 0.8% U3O8
  • 1.1M lbs U3O8in Inferred mineral resources (8,600 tonnes @ 5.8% U3O8)(3)

• Geological setting expected to be amenable to ISR mining, with ~90% of the mineral resource (contained metal) hosted in sandstone

Phoenix Zone A		Phoenix Deposit - Plan View
Schematic Cross Section

Athabasca Sandstone

		Unconformity
Zone A
High-Grade Core

Zone A

Lower Grade

Shell

NOTES:(1) Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River Uranium Project, Saskatchewan, Canada" dated September 24, 2018; (2) Indicated resources are inclusive of Reserves; (3) The PFS does not include any economic analysis based on estimated Inferred resources.

Phoenix Operation:

Application of low-cost ISR mining method to high-grade Athabasca Basin

4

1

5

2 3

ISR Mining Process(1):

1. Mining solution (also known as "lixiviant") is pumped through a permeable orebody via injection well
2. Lixiviant dissolves the uranium as it travels through the orebody
3. Uranium bearing mining solution ("UBS") is pumped back to surface via recovery well
4. UBS is sent to a processing plant on surface for chemical separation of the uranium and reconditioning of lixiviant
5. Lixiviant is returned back to well field for further production

NOTES:(1) Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River Uranium Project, Saskatchewan,	13
Canada" dated September 24, 2018.

Phoenix Freeze Cap:

Novel concept to contain mining solution, using established technology

Artificial freeze cap replicates confining layer typically required for ISR mining operations(1)

•Parallel cased holes drilled from surface and anchored into impermeable basement rock surrounding the Phoenix deposit

•Circulation of low-temperature brine solution through cased pipes will freeze groundwater in sandstone surrounding the deposit

•10 metre thick freeze wall, together with basement rocks will encapsulate Phoenix deposit

Eliminates common environmental concerns with ISR mining and facilitates controlled reclamation

NOTES:(1) Indicative design only. Refer to the Wheeler River Technical Report titled "Pre-feasibility Study Report for the Wheeler River Uranium	14
Project, Saskatchewan, Canada" dated September 24, 2018.

Capital Structure & Corporate Information

Market Summary (1)
Exchanges	TSX: DML, NYSE MKT: DNN
Shares Outstanding	590.2 M
Warrants	1.7 M
Share Units	4.9 M
Options	13.7 M
Fully Diluted Shares	610.5 M
Market Cap - DML @ C$0.49/share(2)	CAD $290 M
Daily Trading Volume - DML(3)	0.76 M Shares
Market Cap - DNN @ U$0.38/share(2)	USD$222 M
Daily Trading Volume - DNN(3)	0.50 M Shares
Website: www.denisonmines.com	Email: [e-mail]

Management & Directors

• David Cates (President & CEO, Director)
• Mac McDonald (Exec. VP & CFO)
• Dave Bronkhorst (VP Operations)
• Tim Gabruch (VP Commercial)
• Dale Verran (VP Exploration)
• Catherine Stefan(Non-Executive Chair)
• W. Robert Dengler (Director)
• Brian D. Edgar (Director)
• Ron F. Hochstein (Director)
• Jack Lundin (Director)
• William A. Rand (Director)
• Geun Park (Director)
• Patricia M. Volker (Director)

NOTES:(1) As per Denison's Q3 2019 Financials; (2) Based on shares outstanding above and DML/DNN share prices as of February 14th, 2020; (3) Average	15
daily trading volume over 90 day period as at February 14th, 2020