Denison Reports Significant Increase in Economic Results for Wheeler River
Denison Mines Corp.
1100 – 40 University Ave
Toronto, ON M5J 1T1
www.denisonmines.com
PRESS RELEASE
Denison Reports Significant Increase in Economic Results for Wheeler River
Toronto, ON – June 26, 2023. Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN:
NYSE American) is pleased to report the results of (i) the Feasibility Study (“Phoenix FS”) completed for In-
Situ Recovery (“ISR”) mining of the high-grade Phoenix uranium deposit (“Phoenix”) and (ii) a cost update
(“Gryphon Update”) to the 2018 Pre-Feasibility Study (“2018 PFS”) for conventional underground mining of
the basement-hosted Gryphon uranium deposit (“Gryphon”). With the successful completion of the Phoenix
FS, Denison has advanced the planned Phoenix ISR project through the technical de-risking process and
has already commenced the first phases of project execution.
Phoenix and Gryphon are part of the Wheeler River Uranium Project (“Wheeler River” or the “Project”),
which is the largest undeveloped uranium mining project in the infrastructure -rich eastern portion of the
Athabasca Basin region in northern Saskatchewan, Canada. Denison has an effective 95% ownership
interest in Wheeler River and is the project operator.
David Cates, Denison’s President & CEO commented, “The Phoenix FS and Gryphon Update confirm
the robust economics of the two projects situated within the Company’s flagship Wheeler River
property, producing base-case after-tax net present value s of $1.6 bi llion and $0.9 billion,
respectively.
After 4.5 years of rigorous technical de-risking and independent third-party validation, Phoenix has
cemented its position as one of the lowest -cost uranium development projects in the world.
Notably, despite the considerable capital cost pressures experienced by the global mining industry
over the last two years, the economics of a Phoenix ISR mining operation remain exceptionally
robust – producing an improvement in projections of NPV and IRR , when compared to the 2018
PFS, as a result of favourable design changes and optimizations. While most contemporary uranium
development projects have not yet been tested against current cost inflation, the results of the
Phoenix FS and Gryphon Update demonstrate that Denison continues to be uniquely positioned to
become a meaningful uranium producer with multiple low-cost development assets.
With the highly positive results of the Phoenix FS, our team has already shifted focus to advancing
front-end engineering and design efforts, with a target of transitioning into detailed design before
the end of the year.”
This press release constitutes a “designated news release” for the purposes of the Company's prospectus
supplement dated September 28, 2021 to its short form base shelf prospectus dated September 16, 2021.
Phoenix FS Highlights:
• Base case pre-tax Net Present Value (“NPV”) (8%) of $2.34 billion (100% ownership-basis) is a
150% increase in the base-case pre-tax NPV8% for Phoenix from the 2018 PFS.
• Very robust base-case pre-tax Internal Rate of Return (“IRR”) of 105.9%.
• Base-case after -tax NPV 8% of $ 1.56 billion (100% basis) and IRR of 9 0.0% – with Denison’s
effective 95% interest in the project equating to a base-case after-tax NPV8% of $1.48 billion.
• Base-case pre- tax and after -tax payback period of 10 months – equating to a reduction of 11
months for the pre-tax payback period from the 2018 PFS.
• Production profile has been optimized, based on ISR mine planning efforts evaluating production
potential for individual well patterns – resulting in an increase to the planned rate of production by
approximately 43% during the first five years of operations.
• Estimated pre-production capital costs of under $420 million (100% basis), yielding an impressive
after-tax NPV to initial capital cost ratio in excess of 3.7 to 1.
• Robust economics easily absorb cost-inflation and design changes impacting both operating and
capital costs, confirming Phoenix’s position with estimated cash operating and all-in costs expected
to be amongst the lowest-cost uranium mines in the world.
• Phoenix FS plans are aligned and costed to meet or exceed environmental criteria expected to be
required by the ongoing regulatory approval process.
• Updated mineral resource estimate, reflecting results of 70 drill holes completed in support of ISR
de-risking and resource delineation activities, has upgraded 30.9 million pounds U3O8 into
Measured mineral resources, and increased the average grade of the Zone A high-grade domain,
which is now estimated to contain 56.3 million pounds U3O8 in Measured and Indicated mineral
resources at an average grade of 46.0% U3O8.
• Upgraded 3.4 million pounds U3O8 into Proven mineral reserves , representing the equivalent of
85% of production planned during the first calendar year of operations.
Completion of Phoenix ISR De-Risking
• The Phoenix FS reflects i ndependent third -party validation of the selection of the ISR mining
method for Phoenix , and builds on the findings from a comprehensive and rigorous multi -year
technical de-risking process highlighted by the highly successful completion of the leaching and
neutralization phases of the Phoenix Feasibility Field Test (“FFT”) in late 2022.
• Through the technical de-risking process, Denison has acquired extensive deposit -specific data
and develop ed a robust ISR mine planning model that involved evaluation of the production
potential for individual well patterns.
• With technical de- risking of the project substantially complete, front-end engineering design
(“FEED”) efforts to support the advancement of the planned Phoenix operation are already
significantly progressed and the Company is on track to transition into detailed design efforts,
consistent with the Company’s Outlook for 2023, before the end of the year.
Gryphon Update Highlights:
• Scope of Gryphon Update was targeted at the review and update of capital and operating costs –
mining and processing plans remaining largely unchanged from the 2018 PFS aside from minor
scheduling and construction sequencing optimizations.
• Base case pre- tax NPV (8%) of $ 1.43 billion (100% basis) is a 148% increase in the base- case
pre-tax NPV8% for Gryphon from the 2018 PFS.
• Strong base-case pre-tax IRR of 41.4%.
• Base-case after-tax NPV8% of $864.2 million (100% basis) and IRR of 37.6 % – with Denison’s
effective 95% interest in the project equating to a base-case after-tax NPV8% of $821.0 million.
• Base-case pre-tax payback period of 20 months, and base -case after-tax payback period of 22
months – equating to a reduction of 17 months for the pre-tax payback period from the 2018 PFS.
• Project remains to be positioned amongst the lowest-cost uranium mines in the world and provides
Denison with an additional source of low-cost potential production to deploy significant free cash
flows expected from Phoenix.
The results of the Phoenix FS and Gryphon Update have been reviewed and approved by the Technical
Committee of Denison’s Board of Directors.
All amounts are in Canadian dollars unless indicated otherwise.
Phoenix ISR Feasibility Study
The Phoenix FS w as completed by Wood Canada Limited ( “Wood”), WSP USA Environment and
Infrastructure Inc. ( “WSP”), SRK Consulting (Canada) Inc. ( “SRK”), and Newmans Geotechnique Inc.
(“Newmans”). The study confirms robust economics and the technical viability of an ISR uranium mining
operation with low initial capital costs and a high rate of return.
The Phoenix FS reflects several design changes and the results of a rigorous technical de-risking program
completed by Denison over the last 4.5 years following the publication of the 2018 PFS, which was
highlighted by the then-novel selection of the ISR mining method for Phoenix.
With the benefit of extensive metallurgical and field testing of all key elements of the proposed ISR mining
operation, and current cost estimates reflecting recent inflationary pressures, the Phoenix FS is expected
to provide Denison with an excellent basis to advance engineering designs in support of a future final
investment decision (“FID”).
Table 1 – Summary of Key Phoenix Operation Parameters (100% Basis)
Mine life 10 years
Proven & Probable reserves(1) 56.7 million lbs U3O8 (220,900 tonnes at 11.6% U3O8)
First 5 years of reserves(2) 41.9 million lbs U3O8 (Average 8.4 million lbs U3O8 / year)
Remaining years of reserves 14.8 million lbs U3O8 (Average 3.0 million lbs U3O8 / year)
Initial capital costs(3) $419.4 million
Average cash operating costs $8.51 (USD$6.28) per lb U3O8
All-in cost(4) $21.73 (USD$16.04) per lb U3O8
(1) See Table 5 below for additional information regarding Proven & Probable reserves.
(2) The first five years is determined by reference to the 60 month period that commences at the start of operations, which
occurs half way through calendar year 1, and ends half way through calendar year 6. See below for details.
(3) Initial capital costs exclude $67.4 million in estimated pre-construction expenditures expected to be incurred pre-FID.
(4) All-in cost is estimated on a pre -tax basis and includes all project operating costs , capital costs post-FID, and
decommissioning costs divided by the estimated number of pounds U3O8 to be produced.
Table 2 – Summary of Phoenix Economic Results (100% Basis)
Base Case PFS Ref. Case(1)
Uranium selling price UxC Spot Price(2)
(~USD$66 to USD$70/lb U3O8)
USD$65/lb U3O8
(Fixed selling price)
Exchange Rate (USD$:CAD$) 1.35 1.30
Discount Rate 8% 8%
Operating profit margin(3) 90.9% 89.9%
Pre-tax NPV8%(4) (Change from 2018 PFS)(7) $2.34 billion (+150%) $2.05 billion (+5%)
Pre-tax IRR(4) 105.9% 98.4%
Pre-tax payback period(6) ~10 months ~ 10 months
Post-tax NPV8%(4)(5) $1.56 billion $1.38 billion
Post-tax IRR(4)(5) 90.0% 83.9%
Post-tax payback period(5)(6) ~10 months ~ 11 months
(1) The “PFS Reference Case” economic analysis reflects the outcome of the current Phoenix FS based on a uranium selling price
that is the same as the “High Case” previously reported from the 2018 PFS, which was based on a fixed uranium selling price
of USD$65 per pound U3O8 and a US to Canadian dollar exchange rate of 1.3 to 1. This case allows for a direct comparison of
the NPV outcome from the Phoenix FS to the 2018 PFS.
(2) Spot price forecast is based on “Composite Midpoint” scenario from UxC’s Q2’2023 Uranium Market Outlook (“UMO”) and is
stated in constant (not-inflated) dollars, see details below.
(3) Operating profit margin is calculated as aggregate uranium revenue less aggregate operating costs, divided by aggregate
uranium revenue. Operating costs exclude all royalties, surcharges and income taxes.
(4) NPV and IRR are calculated to the start of construction activities for the Phoenix operation, and excludes $67.4 million in pre-
FID expenditures.
(5) Post-tax NPV, IRR and payback period are based on the “adjusted Post -tax” scenario, discussed below, which includes the
benefit of certain entity level tax attributes which are expected to be available and used to reduce taxable income from the
Phoenix operation.
(6) Payback period is stated as number of months to payback from the start of uranium production.
(7) Change from 2018 PFS is computed by reference to the same scenario from the 2018 PFS, as discussed below, adjusted to
incorporate certain pre-FID costs for consistent comparability.
Mineral Resource Estimate
The Phoenix mineral resource estimate has been updated to reflect 70 additional drill holes completed
since the previous mineral resource estimate from 2018. The additional drilling consisted primarily of test
wells installed to support ISR de-risking activities and certain targeted resource definition drill holes. As a
result of the additional drilling, 30.9 million pounds U3O8 have been upgraded from Indicated mineral
resources to Measured mineral resources in recognition of the increased confidence in certain areas of
Phoenix Zone A.
The updated Phoenix mineral resource estimate, inclusive of m ineral reserves, is summarized below.
Mineral resources that are not mineral reserves do not have demonstrated economic viability at this time.
Table 3 – Estimated Phoenix Mineral Resources (100% Basis)
Confidence
Category Domain Volume
(m³)
Density
(g/cm³)
Tonnes
(kt)
Average
Grade
(%U3O8)
Contained
U3O8
(Mlbs)
Measured ZoneA_HG 6,729 3.84 25.9 50.7 28.9
ZoneA_LG 16,459 2.33 38.3 2.3 2.0
Total 23,187 2.77 64.2 21.8 30.9
Indicated ZoneA_HG 8,773 3.37 29.6 42.0 27.4
ZoneA_LG 57,858 2.33 134.8 2.0 5.8
ZoneB_HG 4,334 2.66 11.5 22.3 5.7
ZoneB_LG 17,114 2.34 40.1 0.9 0.8
Total 88,079 2.45 216.0 8.3 39.7
Total Measured and Indicated 111,266 2.52 280.2 11.4 70.5
Inferred ZoneA_Bsmt 2,401 2.34 5.6 2.6 0.3
(1) The effective date of the mineral resource estimate is June 23, 2023. The Qualified Person (QP) for the estimate is Mr. Cliff
Revering, P.Eng., an employee of SRK.
(2) Mineral resource estimates are prepared in accordance with CIM Definition Standards (CIM, 2014) and the CIM Estimation of
Mineral Resources and Mineral Reserves Best Practice Guidelines (CIM, 2019).
(3) Mineral resources are reported at a cut-off grade of 0.1% U3O8.
(4) Mineral resources are reported using a uranium price of USD$55/lb.
(5) All figures have been rounded to reflect the relative accuracy of the estimate and may not add due to rounding.
Mining Overview & Mineral Reserve Estimate
Phoenix is planned to be the first uranium IthefSR mining operation in the Athabasca Basin region.
Comprehensive field and laboratory test work has been completed to de- risk the use of the ISR mining
method at the Phoenix deposit – including the highly successful completion of the leaching and
neutralization phases of the FFT at Phoenix in the fall of 2022. Over 3,300 data points have been collected
within Phoenix to advance hydrogeological evaluations, and extensive groundwater flow modelling has
been completed to develop an advanced three-dimensional estimation of the subsurface flows within and
surrounding the Phoenix deposit. The data allowed for modelling of complex hydrogeological and
geochemical datasets, which together with the uranium recovery curve, were used to estimate the rate of
uranium dissolution within the orebody and facilitate the detailed wellfield design and production planning
process.
The uranium recovery curve was obtained empirically from metallurgical testing completed at the
Saskatchewan Research Council (“ SRC”) facility under the supervision of industry experts . Over 125
kilograms (kg) of Phoenix mineralized samples were leached in a variety of settings, including intact cores
under ISR conditions representative of the deposit , and column leaching and remediation tests
representative of specific hydrogeological units (“HGUs”) of the deposit. The results, including those from
(i) the FFT (which confirm the early stages of the leaching curve), (ii) core leach test #4 (which was leached
over 377 days to over 97% recovery), and (iii) core leach test #5 ( which is representative of the HGU
estimated to contain the largest mass of uranium in the deposit ) were used to inform and validat e the
uranium recovery curve.
Based on the results of the mine planning process, m ining activities have been divided into five phases ,
with a total of 74 extraction wells, 172 injection wells, and 22 monitoring wells, as outlined below:
Table 4 –Wellfield composition for Phoenix by phase
Mining
Phase
Extraction
Wells
Injection
Wells
Monitoring
Wells
1 14 36 6
2 12 30 4
3 13 32 4
4 23 44 4
5 16 30 6
Total 74 172 22
An illustration of the mine planning process is provided in Figure 1, which depicts the planned location of
extraction, injection and monitoring wells within the Phase 1 mining area. In general, each extraction well
is surrounded by 4 or more injection wells, the type of which has been selected and/or located to optimize
cost and recovery.
A unique characteristic of the planned Phoenix ISR mine is the use of artificial ground freezing around the
perimeter of the planned Phoenix mining phases to create a vertical hydraulic barrier surrounding the ISR
mining area. The freeze perimeter is a tertiary containment measure and is planned to consist of vertical
freeze wells constructed from surface and extending into the impermeable lower basement rock underlying
the deposit, which are designed to reduce the temperature of and freeze the ground adjacent to the wells
to encircle the mining area with up to a 10-metre thickness of frozen ground.
Mining is planned to occur over a 10-year period, spanning 11 calendar years , with partial years of
production occurring in both the first and final calendar year of the production plan. Progressive reclamation
and decommissioning is planned to commence in each phase of the ore zone once production has ceased.
The Proven and Probable mineral reserves are estimated to be 56.7 million pounds U3O8. This estimate is
based on the aggregate mine feed to the plant and represents 80.6% recovery of the total available uranium
(U3O8) in the measured and indicated mineral resources. Proven mineral reserves are those which were
subject to a recovery test during the FFT in 2022.
Table 5 –Phoenix Mineral Reserves (100% Basis)
Mining Phase by
Confidence Category
Tonnes
(kt)
Grade
(% U3O8)
Recoverable U3O8
(Mlbs)
Proven
Phase 1 6.3 24.5 3.4
Probable
Phase 1 41.3 20.2 18.4
Phase 2 45.2 13.8 13.7
Phase 3 20.3 11.0 4.9
Phase 4 68.9 7.2 10.9
Phase 5 37.0 6.6 5.4
Total 219.0 11.7 56.7
(1) The effective date of the mineral reserve estimate is June 23, 2023. The QP for the estimate is Mr. Dan
Johnson, P.E., an employee of WSP.
(2) Mineral reserves are estimated at a cut -off grade of 0.5% U3O8 based on the ISR mining method , using a
long-term uranium price of USD$50/lb U3O8 and a USD$/CAD$ exchange rate of 1.33. The mineral reserves
are based on a mine operating cost of $0.78/lb U3O8, process operating cost of $5.20/lb U3O8, and process
recovery of 99%, as discussed below.
Processing Overview
Consistent with the 2018 PFS, the Phoenix FS calls for the construction of a processing plant on the
Wheeler River site, which has been designed to receive uranium bearing solution (“UBS”) from the wellfield
for processing to a finished yellowcake product that meets industry standards.
An acidic lixiviant solution is prepared in the process ing plant and transferred to an injection solution
handling system for distribution in the wellfield. The solution is injected through a series of wells arranged
in a pattern surrounding extraction / recovery wells, which are designed to pump the UBS up to surface
once the lixiviant has travelled through the ore zone and dissolved the uranium from the host rock.
Once the UBS is received at the processing plant, removal of impurities such as iron (Fe) and radium (Ra)
occur via Stage 1 (Fe/Ra) precipitation. Next the purified leach solution feeds the Stage 2 yellowcake
precipitation circuit and the yellowcake product is dried and packaged for shipment. The processing plant
has been designed based on an average uranium head grade of the UBS recovered from the wellfield of
22 grams per litre and is expected to recover 96.5% of the uranium feed contained in UBS after a 6 month
ramp up period of the plant (when recovery is expected to be initially 93.4%). Taken together with planned
subsequent recoveries of uranium contained in the Stage 1 (Fe/Ra) precipitation product, total recovered
uranium of 56.2 million pounds U3O8 is planned to be available for sale – representing a combined 99%
recovery rate.
Overall, the processing plant flowsheet remains largely consistent with the 2018 PFS; however, additional
provisions have been included for effluent treatment via a three-stage neutralization process. Whereas the
2018 PFS assumed a “closed loop” processing system , the Phoenix FS design is aligned with the
engineering components and criteria included in the Environmental Assessment (“EA”) for the project ,
which allow for the treatment of process solutions and controlled release of a treated effluent to the
environment. This is an example of how the iterative nature of the EA process has informed project designs
during the Phoenix FS process, to ensure that the plans are aligned and costed to meet or exceed
environmental criteria expected to be required by the ongoing r egulatory approval process. While this
design for effluent treatment has been adopted for the Phoenix FS, the potential remains for ongoing FEED
studies to optimize the processing plant design.
Site Infrastructure
The Phoenix site is compact and designed to limit environmental disturbance. The natural terrain of the
area is used where advantageous, further reducing the impact of the project on the environment. Based
on the Phoenix FS site layout, shown in Figure 2, the primary site facilities will consist of the ISR wellfield,
ISR processing plant, freeze plant, storage pads, power substation and distribution, process ponds, and
camp accommodations for between 100 and 150 occupants. These facilities are contained within an area
estimated to be less than one square kilometre.
Additional on-site infrastructure includes a seven kilometre gravel road from Highway 914 to the site,
electrical power line from the existing SaskPower transmission line located alongside Highway 914, airstrip,
domestic and construction waste management areas, potable water treatment facilities, sewage treatment
facilities, and fuel storage and distribution facilities.
Capital Costs
Estimated initial direct capital costs of $273.8 million represent a 32% increase compared to the initial direct
capital costs from 2018 PFS , which have been adjusted to reflect the movement of offsite infrastructure
costs from direct costs to Other (Owner’s) costs. The increase in initial direct capital costs reflects recent
inflationary trends in labour and materials costs and the impact of several design changes resulting from
the substantive advancement of project designs from the 2018 PFS. Importantly, the design changes in
the Phoenix FS reflect (i) modifications necessary to allow for production plan optimizations, leading to a
43% increase in the rate of production during the first five years of production, (ii) choices made as a result
of the iterative EA evaluation process, and (iii) results of the multi-year technical de-risking program.
Initial capital costs are expected to be incurred during a 24- month construction period that will include the
establishment of site infrastructure (discussed above) , as well as the freeze wall perimeter around the
Phase 1 mining zone and initial wellfield development within Phase 1.
Table 6 – Phoenix Capital Costs ($ millions)
Initial Sustaining Total
Wellfield 63.0 177.1 240.1
ISR processing plant 102.6 - 102.6
Surface facilities 14.7 2.1 16.8
Utilities 34.8 - 34.8
Electrical 19.1 - 19.1
Civil & earthworks 39.6 - 39.6
Decommissioning - 88.8 88.8
Subtotal – Direct Costs 273.8 268.0 541.8
Indirect costs 70.5 31.6 102.1
Other (Owner’s) costs 32.7 - 32.7
Contingency 42.6 23.3 65.9
Total Capital Costs (100%) 419.4 322.9 742.3
(1) Numbers may not add due to rounding.
Contingencies reflect approximately 11% of total capital costs, which is considered appropriate given the
estimate was prepared to meet AACE Class 3 requirements, as well as Denison’s significant experience
with key capital cost drivers through the completion of multiple field test programs at Phoenix since the
2018 PFS.
Taken together with estimated indirect costs, owner’s costs, sustaining and decommissioning capital costs,
contingencies, and with the reallocation of certain costs to the pre-FID period, total life of mine capital costs
are estimated at $742.3 million. This represents a 74% increase in life of mine capital costs compared to
the 2018 PFS.
As is demonstrated by the project’s current NPV in the PFS Reference Case (up 5% from the 2018 PFS),
the economic outcome of the project has not been adversely impacted by the increase in life of mine capital
costs. Significant contributors to the overall increase in capital costs include the wellfield, ISR processing
plant, and decommissioning costs, as further described below:
Wellfield
+$141.0 million
The increase includes the adoption of a phased “freeze wall ” design to
replace the novel “freeze dome” concept included in 2018 PFS. The freeze
dome introduced significant technical risk to the ISR mining process and
added complexity from an environmental protection standpoint. The cost of
the freeze dome was included in initial capital costs, whereas the cost of the
freeze wall is spread over the life of mine, thus significantly reducing the
impact to the NPV from the overall increase in capital costs.
Materials and installation costs for the ISR injection and extraction wells are
now based on the Company’s actual experience in installing both large and
small-diameter test wells during the de -risking process, providing a much
more accurate estimate of costs compared to the 2018 PFS.
Processing Plant
+$47.1 million
The increase reflects a variety of design adjustments to the processing plant,
including those which enable an increase in the planned production rate by
43% during the first 5 years, which has a positive impact on the NPV.
Decommissioning
+$60.2million
The increase reflects the incorporation of costs associated with ore zone
groundwater remediation to achieve targets proposed in the EA; more
detailed management and regulatory cost requirements, improved accuracy
in well decommissioning activities, process plant decontamination and
demolition including transport and disposal of waste materials , additional
costs for decommissioning larger industrial water treatment facilities, and
environmental monitoring labour and analytical costs. A s these increased
capital costs are primarily expected to occur at the end of the mine life, the
impact to the NPV from the increased capital costs is minimized.
Operating Costs
Average estimated operating costs of $8.51 (USD$6.28) per pound U 3O8 produced remain highly
competitive amongst the lowest-cost uranium mining operations globally. Operating costs during the first
five years of production are expected to be $6.64 (USD$4.90) per pound U3O8, benefitting from increased
scale of operations and higher concentrations of uranium contained in recovered UBS. During the
remaining years of production, operating costs are expected to be $13.69 (USD$10.10) per pound U3O8.
As a proportion of operating costs per pound, processing costs have increased from the 2018 PFS, now
accounting for nearly 62%, as compared to 45% in the 2018 PFS. The biggest contributors to the increased
processing costs include reagent usage, as well as estimated costs for reagents, fuel/propane, and labour.
Changes to r eagent usage reflect the results of the Company’s multi -year technical de-risking process,
which has provided a robust data set of metallurgical tests on which the current estimate of reagent usage
has been based, as compared to limited preliminary leach data used for the 2018 PFS.
The cost of reagents, fuel/propane, and labour reflect the impact of inflation and supply chain challenges
experienced through 2022 and into 2023. Based on the timing of this study, reagent and fuel/propane
prices used may be reflective of “peak inflation” pricing and present a possible opportunity for optimization
in future years. These cost increases are expected to impact uranium mining operations globally; however,
few have completed significant operating cycles and/or estimates of future costs in the current cost
environment.