Denison Continues to Expand Gryphon D Series Lenses with Multiple High-Grade Mineralized Intersections
Denison Mines Corp.
1100 – 40 University Ave
Toronto, ON M5J 1T1
www.denisonmines.com
@DenisonMinesCo
PRESS RELEASE
DENISON CONTINUES TO EXPAND GRYPHON D SERIES LENSES
WITH MULTIPLE HIGH-GRADE MINERALIZED INTERSECTIONS
Toronto, ON – March 29, 2017 Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN:
NYSE MKT) is pleased to report multiple high-grade uranium intercepts amongst the D series of mineralized
lenses, which are located outside of the existing r esources estimated for the Gryphon deposit, on the
Company’s 60% owned Wheeler River project. Exploration and infill drilling are ongoing at Wheeler River,
as part of a 16,000 metre winter drill program focused on increasing both the resource size and confidence
of the Gryphon deposit.
Preliminary equivalent grade results (“eU 3O8”) obtained from a downhole radiometric probe, incl ude the
following highlights from exploration drilling on the D series lenses:
• 7.50% eU 3O8 over 1.2 metres (including 9.0% eU 3O8 over 1.0 metres) in WR-689,
• 2.90% eU 3O8 over 1.7 metres (including 3.7% eU 3O8 over 1.3 metres) in WR-689, and
• 1.60% eU 3O8 over 1.0 metre in WR-689D1
New high-grade mineralization was also intersected by drill hole WR-689 through the planes of the Gryphon
B series lenses approximately 125 metres southwest along strike of WR-507D2, which included an
intersection of 19.31% U 3O8 over 1.0 metre (see Denison’s Press Release dated November 17, 2016),
returning the following highlight intersection:
• 2.70% eU 3O8 over 1.9 metres (including 5.1% eU 3O8 over 1.0 metres)
In addition to exploration drilling to expand miner alization outside of the Gryphon deposit, the 2017 winter
drilling program is focused on continuing with infi ll and delineation drilling within the Gryphon depo sit’s A,
B and C series lenses, with the objective of increa sing the level of confidence of the previously rele ased
inferred resources to an indicated level. The 2017 winter infill and delineation drilling program commenced
on the up plunge and down plunge fringes of the deposit and has not yet reached the central, higher grade
and thicker portions of the deposit. To date, multi ple drill holes have intersected higher equivalent grades
and/or thicker intersections when compared with the current inferred grade model, highlighted by the
following:
• 2.50% eU 3O8 over 9.1 metres (including 5.8% eU 3O8 over 1.0 metres and 6.0% eU 3O8 over
2.2 metres) in WR-687D2,
• 4.10% eU 3O8 over 5.8 metres (including 8.1% eU 3O8 over 2.8 metres) in WR-582D2,
• 2.50% eU 3O8 over 4.6 metres (including 8.3% eU 3O8 over 1.2 metres) in WR-684, and
• 0.39% eU 3O8 over 14.2 metres (including 1.2% eU 3O8 over 1.0 metres) in WR-684
Denison's Vice President Exploration, Dale Verran, commented “The 2017 drill program’s results to date
confirm continuity and high-grades of the Gryphon d eposit mineralized lenses and exhibit possible upsi de
to the resource with thicker and/or higher equivalent grades intersected than expected in select portions of
the deposit. In addition, initial drill holes targeting horizons outside of the current resource were successful
in expanding high-grade mineralization along the horizons of the previously identified D series lenses. With
four drill rigs currently turning on the project our team is hard at work until mid-April when the winter program
is expected to be concluded and planning will commence for the sizeable summer drill program.”
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Exploration Drilling Outside of the Gryphon Deposit
The objective of drill holes WR-689 and WR-689D1 was to test the continuity of the D series lenses between
the previous exploration holes completed on an appr oximate 50 x 50 metre spacing. The D series lenses
are not included in the current NI 43-101 resource estimate for the Gryphon deposit and occur footwall, and
within 200 metres to the north and northwest, of th e A, B and C series lenses. Some of the mineraliza tion
that has been discovered while testing the D series of lenses, however, occurs within the A, B and C series
planes. Preliminary radiometric equivalent U 3O8 (“eU 3O8”) results for drill holes WR-689 and WR-689D1
are provided in Table 1 and locations illustrated in Figures 1 to 5.
Table 1: Mineralized intersections from highlight exploration drill holes completed during winter 2017
Section Drill Hole From (m) To (m) Length (m) (5) eU 3O8
(%) (1)(2)(4)
Lens
Designation
5175GP
WR-689D1 560.5 561.5 1.0 0.22 B Series
WR-689D1 566.3 567.3 1.0 0.11 B Series
WR-689D1 570.4 571.4 1.0 0.18 B Series
WR-689D1 668.4 669.4 1.0 0.13 D Series
WR-689D1 675.7 676.7 1.0 0.13 D Series
WR-689D1 (3) 679.7 680.7 1.0 1.6 D Series
WR-689D1 692.3 693.7 1.4 0.23 D Series
5200GP
WR-689 557.2 558.6 1.4 0.54 B Series
WR-689 561.0 562.0 1.0 0.13 B Series
WR-689 564.9 566.8 1.9 2.7 B Series
including (3) 565.6 566.6 1.0 5.1 B Series
WR-689 573.2 574.2 1.0 0.60 B Series
WR-689 584.1 585.1 1.0 0.32 B Series
WR-689 679.6 680.6 1.0 0.50 D Series
WR-689 684.6 685.6 1.0 0.15 D Series
WR-689 711.1 712.8 1.7 2.9 D Series
including (3) 711.3 712.6 1.3 3.7 D Series
WR-689 718.4 719.6 1.2 7.5 D Series
including (3) 718.5 719.5 1.0 9.0 D Series
Notes:
1. eU 3O8 is radiometric equivalent U 3O8 from a calibrated total gamma downhole probe. eU 3O8 results are preliminary in nature
and all mineralized intervals will be sampled and submitted for chemical U 3O8 assay.
2. Intersection interval is composited above a cut- off grade of 0.1% eU 3O8 unless otherwise indicated.
3. Intersection interval is composited above a cut- off grade of 1.0% eU 3O8.
4. Composites are compiled using 1.0 metre minimum ore thickness and 2.0 metres maximum waste
5. As the drill holes are oriented steeply toward t he northwest and the basement mineralization is interpreted to dip moderately
to the southeast, the true thickness of the mineralization is expected to be approximately 75% of the intersection lengths.
The results yielded by WR-689 and WR-689D1 represen t new additional mineralization in both the B and
D series planes and provide additional confidence to the continuity of previously modelled D series lenses.
Additional drill testing for D series lens minerali zation is warranted down-dip and down plunge of the se
intersections. In addition to the immediate follow up of WR-689, D series lens mineralization remains open
along strike to the northeast and southwest.
Five exploration holes (WR-681A, WR-682, WR684A, WR -685 and WR-686) were completed
approximately 50 metres down-dip of the A and B ser ies lenses to test the depth extents of the
mineralization along the southeastern edge of the G ryphon deposit. Despite intersection of favorable
structure and some alteration, none of the holes intersected significant mineralization.
3
Infill and Delineation Drilling of the Gryphon Deposit
The infill and delineation drilling program is desi gned to upgrade the current inferred resources of t he
Gryphon deposit to an indicated level of confidence by increasing the previous 50 x 50 metre drill spa cing
to an approximate 25 x 25 metre spacing. The progr am commenced in 2016, with the completion of an
initial five drill holes. A further 13 drill holes, totaling approximately 6,800 metres, have been completed as
part of the winter 2017 program, with a further 22 drill holes planned to be completed during the remainder
of the winter program and into the summer 2017 program.
Preliminary radiometric equivalent U 3O8 (“eU 3O8”) results for the 13 infill and delineation drill h oles
completed to date during the 2017 winter program are provided in Table 2, and locations shown in Figures
1 to 4. The results can be summarized as follows:
• A Series Lenses: The drill hole mineralized intercepts of the A series lenses are largely consistent
with previously modelled lens interpretations confirming continuity and high-grades. Drill holes WR-
684 and WR-687D2 returned improved intercepts of thickness and/or equivalent grades compared
to the inferred grade model, including 0.39% eU 3O8 over 14.2 metres and 2.5% eU 3O8 over 9.1
meters respectively. The results to date from the A series lenses are illustrated in Figure 2.
• B Series Lenses: The drill hole mineralized intercepts of the B series lenses are largely consistent
with previously modelled lens interpretations confi rming continuity and high-grades. Certain
mineralized intercepts indicated expansion of the B series lenses, as highlighted below and
illustrated in Figure 3;
o Drill hole WR-684 (2.5% eU 3O8 over 4.6 metres) and WR-688D2 (0.47% eU 3O8 over 1.7
metres) intersected mineralization less than 25 met res down plunge and outside of the
current resource estimate, and
o Drill hole WR-683D1 (0.31% eU 3O8 over 1.0 metre and 0.46% eU 3O8 over 1.0 metre) and
drill hole WR-584BD1 (0.11% eU 3O8 over 1.0 metre) intersected mineralization
approximately 50 and 75 metres up plunge and outside of the current resource estimate.
• C Series Lenses: The drill hole mineralized intercepts of the C ser ies planes confirmed the up
plunge and down plunge limits of the C series lense s which are included in the current resource
estimate, as illustrated in Figure 4. Infill and de lineation drilling is yet to commence for the main
portion of the C series lenses which are included in the current resource estimate.
Table 2: Mineralized intersections from infill and delineation drill holes completed during winter 2017
Section Drill Hole From (m) To (m) Length (m) (5) eU 3O8
(%) (1)(2(4))
Lens
Designation
4775GP
WR-584BD1 624.8 627.8 3.0 2.0 A Series
including (3) 626.0 627.6 1.6 3.7 A Series
WR-584BD1 637.6 638.6 1.0 0.11 B Series
4825GP
WR-683 No significant mineralization
WR-683D1 635.8 638.9 3.1 1.8 A Series
including (3) 636.2 638.2 2.0 3.5 A Series
WR-683D1 645.2 646.2 1.0 0.31 B Series
WR-683D1 657.5 658.5 1.0 0.46 B Series
4875GP
WR-687D1 672.0 673.0 1.0 0.40 A Series
WR-687D1 673.4 674.4 1.0 0.10 A Series
WR-687D1 676.6 678.0 1.4 1.6 B Series
4
including (3) 676.8 677.8 1.0 2.2 B Series
WR-687D1 682.7 683.7 1.0 0.55 B Series
WR-575D1 626.2 625.9 1.5 0.36 A Series
4900GP
WR-687 681.4 682.4 1.0 0.14 A Series
WR-687 685.0 686.5 1.5 0.88 A Series
WR-687 685.2 686.2 1.0 1.2 B Series
WR-687 690.8 691.8 1.0 0.12 B Series
WR-687D2 (3) 648.9 649.9 1.0 1.8 A Series
WR-687D2 652.8 661.9 9.1 2.5 A Series
including (3) 653.9 654.9 1.0 5.8 A Series
including (3) 656.4 657.7 1.3 1.6 A Series
including (3) 659.4 661.6 2.2 6.0 A Series
WR-687D2 676.3 677.3 1.0 0.14 B Series
WR-687D2 686.2 687.4 1.2 0.15 B Series
5125GP
WR-688 774.1 778.9 4.8 0.51 A Series
including (3) 776.6 777.6 1.0 1.1 A Series
WR-688D2 756.5 757.5 1.0 0.33 A Series
WR-688D2 761.2 762.7 1.5 3.0 A Series
including (3) 761.3 762.3 1.0 4.3 A Series
WR-688D2 767.5 769.2 1.7 0.47 B Series
5150GP
WR-582D2 741.6 742.6 1.0 0.72 A Series
WR-582D2 746.2 752.0 5.8 4.1 A Series
including (3) 748.8 751.6 2.8 8.1 A Series
WR-684 796.1 797.1 1.0 0.11 A Series
WR-684 813.7 827.9 14.2 0.39 A Series
including (3) 813.7 814.7 1.0 1.2 A Series
WR-684 830.5 835.1 4.6 2.5 B Series
including (3) 831.0 832.2 1.2 8.3 B Series
WR-688D1 766.5 768.9 2.4 0.72 A Series
including (3) 767.6 768.6 1.0 1.4 A Series
WR-688D1 775.5 776.5 1.0 0.16 A Series
5175GP
WR-684D1 803.6 805.2 1.6 0.18 A Series
WR-684D1 806.4 807.4 1.0 0.13 A Series
WR-684D1 808.3 810.2 1.9 0.18 A Series
WR-684D1 813.6 815.5 1.9 0.18 A Series
WR-684D1 831.5 832.5 1.0 0.12 A Series
Notes:
1. eU 3O8 is radiometric equivalent U 3O8 from a calibrated total gamma downhole probe. eU 3O8 results are preliminary in nature
and all mineralized intervals will be sampled and submitted for chemical U 3O8 assay.
2. Intersection interval is composited above a cut- off grade of 0.1% eU 3O8 unless otherwise indicated.
3. Intersection interval is composited above a cut- off grade of 1% eU 3O8.
4. Composites are compiled using 1.0 metre minimum ore thickness and 2.0 metres maximum waste
5. As the drill holes are oriented steeply toward t he northwest and the basement mineralization is interpreted to dip moderately
to the southeast, the true thickness of the mineralization is expected to be approximately 75% of the intersection lengths.
5
Illustrative Figures & Further Details
A plan map of the northeast plunging Gryphon mineralized lenses, projected up to the simplified basement
geology at the sub-Athabasca unconformity, is provi ded in Figure 1. The plan map shows the location of
the A, B, C and D series lenses interpreted to the end of 2016 with the winter 2017 mineralized pierce points
shown as yellow stars. The inset on Figure 1 shows a schematic cross section of the A, B, C and D seri es
lenses and their respective inclined longitudinal s ection windows (as shaded rectangles). Figures 2 to 5
provide inclined longitudinal sections of the Gryph on A, B, C and D series lenses respectively. Shown on
the inclined longitudinal sections are the various mineralized lenses projected to their respective pl anes
and drill hole pierce points. Drill hole pierce po ints prior to the winter 2017 program are shown as black
circles whereas winter 2017 pierce points are shown as either yellow stars (mineralized) or grey circles (not
significantly mineralized).
It should be noted for Figures 1 to 5 that mineralized lenses are designated either A, B, C or D series, and
coloured accordingly, based on the interpreted stra tigraphic planes in which they occur (i.e. their po sition
relative to the different geological units and fault structures identified). In the 2016 Denison Press Releases
all new lenses defined outside of the Gryphon deposit’s A, B and C series lenses, which constitutes the NI
43-101 inferred resource estimate, were designated D series lenses. Further geological data from 2017
drilling and an improved geological model has allow ed Denison to re-classify some of the previously
modelled D series mineralized lenses into new A, B or C series lenses based on their stratigraphic position
ahead of future resource estimation. The modelled mineralized lenses shown in Figures 1 to 5 are defined
using a 0.05% U3O8 or eU 3O8 grade shell and minimum thickness of two metres. There is no certainty that
the modelled mineralized lenses shown will constitute future mineral resources and they may be subject to
modifications as further drilling data becomes available.
Further details regarding the Gryphon deposit and t he current mineral resource estimates are provided in
the NI 43-101 Technical Report for the Wheeler Rive r project titled “Preliminary Economic Assessment for
the Wheeler River Uranium Project, Saskatchewan, Ca nada" dated April 8, 2016 with an effective date of
March 31, 2016. A copy of this report is availabl e on Denison’s website and under its profile on SEDAR
at www.sedar.com and on EDGAR at www.sec.gov/edgar.shtml.
Qualified Persons
The disclosure of a scientific or technical nature contained in this news release was prepared by Dale
Verran, MSc, Pr.Sci.Nat., Denison's Vice President, Exploration, who is a Qualified Person in accordan ce
with the requirements of NI 43-101. For a descript ion of the assay procedures and the quality assuran ce
program and quality control measures applied by Denison, please see Denison's Annual Information Form
dated March 24, 2016 filed under the Company's profile on SEDAR (www.sedar.com).
About Wheeler River
Wheeler River is the largest undeveloped high-grade uranium project in the infrastructure rich eastern
portion of the Athabasca Basin region, in northern Saskatchewan. The project is a joint venture betwe en
Denison (60% and operator), Cameco Corp. (30%), and JCU (Canada) Exploration Company Limited
(10%), and is host to the high-grade Gryphon and Ph oenix uranium deposits discovered by Denison in
2014 and 2008, respectively. The Gryphon deposit is hosted in basement rock and is currently estimated
to contain inferred resources of 43.0 million pound s U 3O8 (above a cut-off grade of 0.2% U 3O8) based on
834,000 tonnes of mineralization at an average grade of 2.3% U 3O8. The Phoenix unconformity deposit is
located approximately 3 kilometres to the southeast of Gryphon and is estimated to include indicated
resources of 70.2 million pounds U 3O8 (above a cut-off grade of 0.8% U 3O8) based on 166,000 tonnes of
mineralization at an average grade of 19.1% U 3O8, and is the highest grade undeveloped uranium deposit
in the world.
On April 4th, 2016, Denison announced the results of a Preliminary Economic Assessment (“PEA”) for the
Wheeler River Project, which considers the potentia l economic merit of co-developing the high-grade
Gryphon and Phoenix deposits as a single undergroun d mining operation. The PEA returned a base case
pre-tax Internal Rate of Return ("IRR") of 20.4% ba sed on the current long term contract price of uran ium
(US$44.00 per pound U 3O8), and Denison's share of estimated initial capital expenditures ("CAPEX") of
6
CAD$336M (CAD$560M on 100% ownership basis). Exploration results from the winter and summer 2016
drilling program have not been incorporated into the resource estimate or the PEA. The PEA is preliminary
in nature and includes inferred mineral resources t hat are considered too speculative geologically to have
the economic considerations applied to them to be c ategorized as mineral reserves, and there is no
certainty that the preliminary economic assessment will be realized. Mineral resources are not mineral
reserves and do not have demonstrated economic viab ility. On July 19th, 2016 Denison announced the
initiation of a Pre-Feasibility Study ("PFS") for t he Wheeler River property and the complimentary
commencement of an infill drilling program at the G ryphon deposit to bring the inferred resources to a n
indicated level of confidence.
About Denison
Denison is a uranium exploration and development company with interests focused in the Athabasca Basin
region of northern Saskatchewan. Including its 60% owned Wheeler River project, which hosts the high-
grade Phoenix and Gryphon uranium deposits, Denison 's exploration portfolio consists of numerous
projects covering over 350,000 hectares in the infr astructure rich eastern Athabasca Basin. Denison's
interests in Saskatchewan also include a 22.5% ownership interest in the McClean Lake joint venture, which
includes several uranium deposits and the McClean L ake uranium mill, which is currently processing ore
from the Cigar Lake mine under a toll milling agreement, plus a 25.17% interest in the Midwest deposit and
a 63.01% interest in the J Zone deposit on the Wate rbury Lake property. Both the Midwest and J Zone
deposits 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, th ese 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-looking information
pertaining to the following: exploration (including drilling) and evaluation act ivities, plans and objectives; potential mineraliza tion of
drill targets; the estimates of Denison's mineral resources and the results of its PEA.
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, uncert ainties and other factors that may cause the actual results, level of activity,
performance or achievements of Denison to be materi ally different from those expressed or implied by s uch forward-looking
statements. Denison believes that the expectations reflected in this forward-looking information are r easonable but there can be no
assurance that such statements will prove to be acc urate and may differ materially from those anticipa ted 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 “Risk
Factors” in Denison’s Annual Information Form dated March 24, 2016 available under its profile at www.sedar.com and in its Form
40-F available at www.sec.gov/edgar.shtml . These factors are not, and should not be construed as being, exhaustive.
Accordingly, readers should not place undue relianc e on forward-looking statements. The forward-lookin g information contained in
this press release is expressly qualified by this cautionary statement. 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 its expectations except as otherwise required by applicable legislation.
7
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, 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.
8
Figure 1: Plan map of the northeast plunging Gryphon mineralized lenses projected up to the simplified basement geology at the
sub-Athabasca unconformity.