Denison Announces Significant Increase in Mineral Resource

Denison Announces Significant Increase in Mineral Resource Estimates
for the Phoenix Deposits 
TORONTO, ONTARIO -- (Marketwire) -- 01/09/13 -- Denison Mines Corp.
(TSX:DML)(NYSE MKT:DNN)(NYSE Amex:DNN) ("Denison" or the "Company")
is pleased to announce an updated Mineral Resource Estimate for the
high grade Phoenix A and Phoenix B uranium deposits on its Wheeler
River project in Northern Saskatchewan.  
For the combined Phoenix A and B deposits, the total Indicated
Mineral Resource is estimated to contain 52,300,000 lbs U3O8 based on
152,400 tonnes of mineralization at an average grade of 15.6% U3O8.
Additionally, the total Inferred Mineral Resource is estimated to
contain 7,600,000 lbs U3O8 based on 11,600 tonnes of mineralization
with an average grade of 29.8% U3O8. This Mineral Resource estimate
update represents a 47% increase in Indicated lbs U3O8 and a 100%
increase in Inferred lbs U3O8 over the previous Mineral Resource
estimate done in 2010. 
The Wheeler River property lies between the McArthur River mine and
Key Lake mill complex in the Athabasca Basin in northern
Saskatchewan. Denison is the operator and holds a 60% interest in the
project. Cameco Corporation holds a 30% interest and JCU (Canada)
Exploration Company, Limited holds the remaining 10% interest. 
Summary Table 
The following table summarizes the Mineral Resource estimate by
deposit and classification.  
2012 Phoenix Mineral Resource Estimate Summary  
(Effective Date December 31, 2012) 

                                                       Grade    Million lbs
Category               Deposit         Tonnes       (% U3O8)           U3O8
Indicated            A Deposit        133,500           15.8           46.5
Indicated            B Deposit         19,000           14.1            5.9
Total Indicated                       152,400           15.6           52.3
Inferred             A Deposit          6,300           51.7            7.2
Inferred             B Deposit          5,300            3.5            0.4
Total Inferred                         11,600           29.8            7.6


1.  CIM Definitions were followed for classification of Mineral Resources. 
2.  Mineral Resources are reported above a cut-off grade of 0.8% U3O8. 
3.  The cut-off grade is based on internal conceptual studies and a price of
    $50 per lb U3O8. 
4.  Numbers may not add due to rounding.

Geology and Mineralization 
Mineralization at Phoenix shares many similarities with other
unconformity related Athabasca uranium deposits. It occurs along the
sub-Athabasca unconformity at its intersection with a moderately east
dipping fault zone which results in an elongate and sub-horizontal
shape to the deposits. Fault zones are best developed in graphitic
metasediments in the underlying basement rocks. Mineralization varies
from disseminated to massive, with several very high grade drill hole
intersections averaging greater than 50% U3O8 over true thicknesses
up to 6.0 meters. With the completion of this Mineral Resource
estimate, the Phoenix deposits now belong to a select group of very
high grade unconformity uranium deposits that includes the prolific
McArthur River mine (37 kilometers to the northeast) and the soon to
be producing Cigar Lake deposit (80 kilometers to the northeast). 
Estimation Methodology 
Denison has estimated Mineral Resources for the Phoenix Deposits with
data collected from several surface diamond drilling campaigns from
2008 to 2012. Uranium grade data is comprised of chemical assays on
split drill core samples. All assays were completed by SRC
Geoanalytical Laboratories in Saskatoon, Saskatchewan using the
Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES)
method. Quality control and quality assurance protocols for the
chemical assays include the use of standard reference materials,
blanks, check assays and duplicate samples. In those cases where
drill core recovery is poor, chemical assays have been replaced with
equivalent uranium grades obtained from down-hole radiometric
Geology, structure, and the size and shape of the mineralized zones
has been interpreted using data from 168 diamond drill holes which
resulted in three dimensional wireframe models that represent 0.05%
U3O8 grade envelopes. Models of mineralization at each of the two
deposits contain higher grade zones within an envelope of lower grade
material, resulting in a total of four estimation domains - Phoenix A
higher grade, Phoenix A lower grade, Phoenix B higher grade and
Phoenix B lower grade. 
Based on 165 dry bulk density determinations, Denison developed a
formula relating bulk density to grade which was used to assign a
density value to each assay. Bulk density values were used to weight
grades during the resource estimation process and to convert volume
to tonnage. 
Uranium grade times density (GxD) values and density (D) values were
interpolated into each domain block model using an inverse distance
squared (ID2) algorithm. Hard domain boundaries were employed such
that drill hole grades from any given domain could not influence
block grades in any other domain. Very high grade composites were not
capped but grades greater than a designated threshold level for each
domain were subject to restricted search ellipse dimensions in order
to reduce their influence. Block grade was derived from the
interpolated GxD value divided by the interpolated D value for each
block. Block tonnage was based on volume times the interpolated D
The Mineral Resources for the Phoenix Deposits were classified as
Indicated and Inferred based on drill hole spacing and apparent
continuity of mineralization. The block models were validated by
comparison of domain wireframe volumes with block volumes, visual
comparison of composite grades with block grades, comparison of block
grades with composite grades used to interpolate grades, and
comparison with estimation by a different method. 
Roscoe Postle Associates Inc. (RPA) was retained by Denison on behalf
of the Wheeler River Joint Venture to audit the Mineral Resource
estimate and to prepare an independent Technical Report in accordance
with the requirements of National Instrument 43-101. William E.
Roscoe, Ph.D. P.Eng. of RPA, is the independent "Qualified Person"
responsible for the Mineral Resource estimate. The Technical Report
supporting the estimate will be filed on SEDAR ( 
Looking Ahead 
Denison is planning to complete large winter and summer drilling
programs similar in scale to that completed in 2012. The winter 2013
drilling program is expected to begin on January 16th, with two
drills primarily devoted to exploring for additional mineralization
near Phoenix and at other targets on the Wheeler River property.
Particular emphasis will be placed on following the trend of
mineralization and alteration along strike to the northeast of
Phoenix A. 
Qualified Person 
The disclosure of a scientific or technical nature contained in this
news release was prepared by Steve Blower P.Geo., Denison's Vice
President, Exploration, who is a Qualified Person in accordance with
the requirements of NI 43-101 and has been approved by William E.
Roscoe, Ph.D. P. Eng. of RPA. For a description of the quality
assurance program and quality control measures applied by Denison,
please see Denison's Annual Information Form dated March 28, 2012
filed under the Company's profile on SEDAR at 
About Denison 
Denison Mines Corp. is a uranium exploration and development company
with interests in exploration and development projects in
Saskatchewan, Zambia and Mongolia. Including the world class Phoenix
deposits, located on its 60% owned Wheeler River project, Denison's
exploration project portfolio includes 26 projects and totals over
330,000 hectares in the Eastern Athabasca Basin region of
Saskatchewan. 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 Lake uranium mill,
one of the world's largest uranium processing facilities and a 25.17%
interest in the Midwest deposit, which is located 15 kilometres from
the McClean Lake mill. Internationally, Denison owns 100% of the
conventional heap leach Mutanga project, in Zambia, and an 85%
interest in the in-situ recovery projects held by the Gurvan Saihan
Joint Venture, in Mongolia. 
Denison is engaged in mine decommissioning and environmental services
through its Denison Environmental Services (DES) division and is the
manager of Uranium Participation Corporation (TSX:U), a publicly
traded company which invests in uranium oxide in concentrates and
uranium hexafluoride. 
Cautionary 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" or
"does not expect", "is expected", "budget", "scheduled", "estimates",
"forecasts", "intends", "anticipates" or "does not anticipate", or
"believes", 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". 
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
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 correct and such forward-looking
information included in this press release should not be unduly
relied upon. This information speaks only as of the date of this
press release. In particular, this press release may contain
forward-looking information pertaining to the following: the
estimates of Denison's mineral resources; capital expenditure
programs; estimated production costs, exploration and development
expenditures and reclamation costs; expectations of market prices and
costs; supply and demand for uranium; possible impacts of litigation
and regulatory actions on Denison; exploration, development and
expansion plans and objectives; Denison's expectations regarding
raising capital and adding to its mineral resources through
acquisitions and development; and receipt of regulatory approvals,
permits and licences and treatment under governmental regulatory
There can be no assurance that such statements will prove to be
accurate, as Denison's actual results and future events could differ
materially from those anticipated in this forward-looking information
as a result of those factors discussed in or referred to under the
heading "Risk Factors" in Denison's Annual Information Form dated
March 28, 2012, available at, and in its Form
40-F available at, as well as the following:
global financial conditions, the market price of Denison's
securities, volatility in market prices for uranium; ability to
access capital, changes in foreign currency exchange rates and
interest rates; liabilities inherent in mining operations;
uncertainties associated with estimating mineral reserves and
resources and production; uncertainty as to reclamation and
decommissioning liabilities; failure to obtain industry partner and
other third party consents and approvals, when required; delays in
obtaining permits and licenses for development properties;
competition for, among other things, capital, acquisitions of mineral
reserves, undeveloped lands and skilled personnel; public resistance
to the expansion of nuclear energy and uranium mining; uranium
industry competition and international trade restrictions; incorrect
assessments of the value of acquisitions; property title risk;
geological, technical and processing problems; the ability of Denison
to meet its obligations to its creditors; actions taken by regulatory
authorities with respect to mining activities; the potential
influence of or reliance upon its business partners, and the adequacy
of insurance coverage. 
Accordingly, readers should not place undue reliance on
forward-looking statements. These factors are not, and should not be
construed as being, exhaustive. 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. The
forward-looking 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 Denison's
expectations except as otherwise required by applicable legislation. 
Cautionary Note to United States Investors Concerning Estimates of
Measured, Indicated and Inferred Resources: This press release may
use the terms "Measured", "Indicated" and "Inferred" 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.
Denison Mines Corp.
Ron Hochstein
President and Chief Executive Officer
(416) 979-1991 ext 232 
Denison Mines Corp.
Steve Blower
Vice President, Exploration
(604) 689-7842
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