NexGen Announces Positive Results from Arrow Project Studies
NexGen Announces Positive Results from Arrow Project Studies
Vancouver, BC, June 13, 2018 – NexGen Energy Ltd. (“NexGen” or the “Company”) (TSX:NXE, NYSE MKT:NXE)
is pleased to report the positive results from Pre‐Feasibility‐stage technical studies including metallurgical,
geotechnical, and hydrogeological assessments. These studies were conducted on the basement‐hosted Arrow
Deposit, located on the Company’s 100% owned Rook I project in Saskatchewan’s Athabasca Basin.
Highlights:
Metallurgical Study
The Bench‐Scale Metallurgical Study has demonstrated high purity yellowcake product can be produced by
using peroxide and MgO. The final product, produced yellowcake, meeting or surpassing industry standards.
High recovery rates confirmed.
o Leaching test samples representing anticipated typical mill feed resulted in 97.6% of uranium
was recovered.
o Optimized solvent extraction (“SX”) resulted in 99.6% of uranium extracted.
Strength tests meet or exceed all requirements set forth in the original design for a potential Paste‐
Backfill to be used for underground stope stability.
o Paste‐Backfill samples composed of representative uranium tailings mixed with binder,
underwent an initial 28‐day Unconfined Compressive Strength (“UCS”) test with results
surpassing the targeted high‐strength Backfill of 1.5 MPa outlined in the initial mine design
in the Preliminary Economic Assessment.
Geotechnical Study
Conventional long‐hole stoping mining method confirmed.
o The geotechnical assessment supports the conventional long‐hole stoping mining method
including the use of longitudinal and transverse stopes, 30 m level spacing, and the nominal
stope strike length of 15 m to 30 m. This represents an excellent stope stability range for
underground mining in competent conditions.
Hydrogeological Study
Hydraulic conductivity consistent with that predicted in basement rocks.
o The hydrogeological study measured hydraulic conductivity. Results were as predicted given
mineralization is completely hosted in the crystalline basement rocks. Conductivity which
measures the presence of water, decreases with depth and is expected to be lowest at depths
associated with mine workings.
Underground Tailings Management Facility is displayed in Figure 1 below.
Development, Activities & Financial
Pre‐feasibility staged technical studies including geotechnical work, hydrogeological work, and
metallurgy continue in advance of the updated Mineral Resource Estimate and maiden Pre‐Feasibility
Study scheduled for the end of Q3 / early Q4 2018.
A summer drilling program is in the final stages of preparation and will begin imminently.
The Company has cash on hand of approximately ~$145 million.
Troy Boisjoli, Vice‐President, Operations and Project Development, commented: “Results from the
metallurgical study demonstrate high recovery of uranium during the leaching and optimized solvent
extraction process. Furthermore, positive results from Paste‐Backfill test work has confirmed proof of concept
for potential application of an underground tailings management facility. In addition to responsible tailings
management, mixing tailings with cement and depositing it back underground will facilitate ongoing and
continued reclamation while in operation. Geotechnical results have confirmed the nature of the basement‐
hosted Arrow Deposit can support conventional long‐hole stoping mining methods. The hydrogeological study
demonstrates hydraulic conductivity is entirely consistent with that of basement‐hosted deposits and is
favourable for mine development. With every stage of development NexGen continues to confirm the
robustness of the Arrow Project.”
Leigh Curyer, Chief Executive Officer, commented: “Development studies continue to emphasize the unique
technical characteristics of the Arrow Project. These results quantify high recovery rates, non‐detect
deleterious metals and competency of the basement rocks. The maiden Pre‐Feasibility Study which will
incorporate an updated Mineral Resource Estimate is on schedule for release at end of Q3 or early Q4. In the
interim, the summer 2018 drilling program will commence imminently which will continue to focus on
determining the overall scale of Arrow and near‐Arrow mineralization as well as further define site
characterization for development.”
Study Details:
Bench‐Scale Metallurgical Study:
Wood PLC (formerly AMEC Foster Wheeler) approved selected drill core samples and interpreted the results.
The bench‐scale metallurgical samples were analyzed by the Saskatchewan Research Council Laboratories
(“SRC”), pilot‐scale metallurgical testing is ongoing.
Thirteen composite samples were prepared from the crushed core assay rejects and used for
leaching/QEMSCAN/acid generation (PAG)/tailings preparation for paste backfill tests. The samples were
blended and homogenized in a mixer to prepare the composite sample.
Paste‐Backfill Testing:
Testing six varying compositions of representative uranium tailings combined with binder underwent
an initial 28‐day UCS testing. The most successful of the mixtures came from sample M6, this mixture
combined 61.01% uranium tailings with a resulting 2.15 MPa from UCS testing, surpassing the targeted
high‐strength Backfill of 1.5 MPa.
Modal mineralogy analysis:
QEMSCAN analyses on the Medium Grade (“MG”) composite and A1 to A5 individual shear zone
samples indicate that uraninite was present as fresh and altered uraninite. No primary Mo‐bearing
minerals were identified in any samples, and all samples were dominated by clay minerals with
uraninite most commonly associated with the clay minerals
Mill work index measurements:
Five composite samples were prepared from full diameter NQ core for comminution testing, including
SAG mill work index and Bond Ball mill work index “SAGDesinTM tests”. The results categorized the
samples as medium hardness materials which indicates standard grinding conditions.
Leaching analysis:
Batch leaching on the Medium Grade (“MG”) composite sample (50kg) was performed at baseline
conditions to generate adequate quantity of baseline residue and pregnant leach solution (PLS) for the
downstream tests. The MG composite sample uranium leaching recovery was 97.6%.
Solvent extraction testing and filtration test:
Optimized solvent extraction (“SX”) resulted in 99.6% of U extracted with a phase separation time of
3.1 minutes. The SX testing results on the settling filtrates, which were produced from the settling
tests of the leaching slurry at the seven leaching conditions, support optimized leaching conditions for
Low Grade, Medium Grade and High Grade samples. Both the U extraction rate (from 98.7% to 99.7%)
and the phase separation time (3.7 to 5.9 minutes) were in the expected range.
The Bench‐Scale Metallurgical Study has demonstrated high purity yellowcake product can be produced by
using peroxide and MgO. The final product produced yellowcake, meeting or surpassing industry standards.
Geotechnical Study:
BGC Engineering Inc. (“BGC”) interpreted results from available geotechnical data, including geo‐mechanical
property testing completed by SNC Lavalin (Saskatoon, SK) and Golder Associates Ltd. (Burnaby, BC).
Six geotechnical diamond drill holes were completed in the summer of 2017. The holes were designed to
characterize the geotechnical and hydrogeological conditions in support of the envisioned Pre‐feasibility study
(PFS) mine design, targeting:
Life‐of‐mine infrastructure
The A2 and A3 shears
The crown pillar
The core was logged using the industry standard RMR76 system and Q rating system, and regular point load
tests were performed to aid in the determination of intact rock strength. Representative core samples were
selected from five of the drill holes and sent to SNC Lavalin (Saskatoon, SK) and Golder Associates Ltd. (Burnaby,
BC) for geo‐mechanical properties testing. The testing program included unconfined compressive strength,
triaxial strength, and tensile strength tests on rock core samples, direct shear tests on discontinuities, index
tests on discontinuity infills and X‐ray diffraction (XRD) tests on rock specimens. On four of the geotechnical
holes, 39 downhole packer tests were completed to measure the hydraulic conductivity in various rock units
and along structures and an acoustic televiewer survey was performed to collect in‐situ structural
measurements. Vibrating wire piezometers were installed in four of the holes to allow for long‐term monitoring
of water pressures in specific intervals.
In addition to the 2017 data, NexGen provided BGC with a geotechnical data set that was collected using the
RMR89 system (termed RMR’) and consists of 178 drill holes within or proximal to the Arrow Deposit. BGC
interpreted the available data and proposed eight geotechnical domains:
1. Overburden (sand, cobbles, boulders)
2. Cretaceous (siltstone/mudstone/sandstone/coal seams)
3. Devonian (sandstone)
4. Athabasca (sandstone)
5. Paleoweathered basement (gneiss)
6. Faults and shear zones (gneiss, altered gneiss, +/‐ mineralization)
7. Unaltered basement (gneiss)
8. Altered basement (altered gneiss, +/‐ mineralization)
Using a 30 m level height, BGC recommends that transverse stopes have a span of 10 m to 15 m, at a stope
strike length of (15 to 30 m) (check this is consistent with the bullet point in highlights, respectively. For
longitudinal stopes, stope length is limited by the unsupported walls (minimal level of ground support) ranging
from 20 m to 30 m, dependant on location. Stope lengths greater than 20 m to 30 m would utilize cable bolt
support in the walls.
Hydrogeological Study:
BGC Engineering Inc. (“BGC”) interpreted results from data collected on site by NexGen Energy personnel.
BGC estimated the hydraulic conductivity of the crystalline basement rock from data obtained from the 31
packer tests performed on the geotechnical diamond drill holes.
The hydrogeological investigation indicates the Arrow Deposit has basement hydraulic conductivity values
ranging from 5.2x10‐10 to 1.7x10‐6 m/s. These values are typical of metaphoric, crystalline basement rock.
Figure 1: Underground Tailings Management Facility (RPA 2017)
About NexGen
NexGen is a British Columbia corporation with a focus on the acquisition, exploration and development of
Canadian uranium projects. NexGen has a highly experienced team of uranium industry professionals with a
successful track record in the discovery of uranium deposits and in developing projects through discovery to
production.
NexGen owns a portfolio of prospective uranium exploration assets in the Athabasca Basin, Saskatchewan,
Canada, including a 100% interest in Rook I, location of the Arrow Deposit in February 2014, the Bow discovery
in March 2015, the Harpoon discovery in August 2016 and the Arrow South discovery in July 2017. The Arrow
deposit's updated mineral resource estimate with an effective date of December 20, 2016 was released in
March 2017, and comprised 179.5 M lbs U3O8 contained in 1.18 M tonnes grading 6.88% U3O8 in the Indicated
Mineral Resource category and an additional 122.1 M lbs U3O8 contained in 4.25 M tonnes grading 1.30%
U3O8 in the Inferred Mineral Resource category.
Leigh Curyer
Chief Executive Officer
NexGen Energy Ltd.
+1 604 428 4112
www.nexgenenergy.ca
Travis McPherson
Vice President Corporate Development
NexGen Energy Ltd.
+1 604 428 4112
http://www.nexgenenergy.ca
For Media Inquiries:
Jonathan Goldberg
KCSA Strategic Communications
+1 212 896 1282
Technical Information
Natural gamma radiation in drill core reported in this news release was measured in counts per second (cps)
using a Radiation Solutions Inc. RS‐120 gamma‐ray scintillometer. The reader is cautioned that total count
gamma readings may not be directly or uniformly related to uranium grades of the rock sample measured; they
should be used only as a preliminary indication of the presence of radioactive minerals.
Split core samples will be taken systematically, and intervals will be submitted to SRC Geoanalytical
Laboratories (an SCC ISO/IEC 17025: 2005 Accredited Facility) of Saskatoon for analysis. All samples sent to SRC
will be analyzed using ICP‐MS for trace elements on partial and total digestions, ICP‐OES for major and minor
elements on a total digestion, and fusion solution of boron by ICP‐OES. Mineralized samples are analyzed for
U3O8 by ICP‐OES and select samples for gold by fire assay. Assay results will be released when received and
after stringent internal QA/QC protocols are passed.
All scientific and technical information in this news release has been prepared by or reviewed and approved
by Mr. Troy Boisjoli, Geoscientist Licensee, Vice President – Operations & Project Development for NexGen.
Mr. Boisjoli is a qualified person for the purposes of National Instrument 43‐101 Standards of Disclosure for
Mineral Projects ("NI 43‐101"), and has verified the sampling, analytical, and test data underlying the
information or opinions contained herein by reviewing original data certificates and monitoring all of the data
collection protocols.
For details of the Rook I Project including the quality assurance program and quality control measures applied
and key assumptions, parameters and methods used to estimate the mineral resource please refer to the
technical report entitled "Technical Report on the Preliminary Economic Assessment of the Arrow Deposit,
Rook 1 Property, Province of Saskatchewan, Canada" dated effective September 1, 2017 (the "Rook 1 Technical
Report") prepared by Jason J. Cox, David M. Robson, Mark B. Mathisen, David A. Ross, Val Coetzee and Mark
Wittrup, each of whom is a "qualified person" under NI 43‐101. The Rook I Technical Report is available for
review under the Company's profile on SEDAR at www.sedar.com.
U.S. investors are advised that while the terms "indicated resources" and "inferred resources" are recognized
and required by Canadian regulations, the U.S. Securities and Exchange Commission does not recognize these
terms. U.S. investors are cautioned not to assume that any part or all of the material in these categories will
ever be converted into mineral reserves.
Forward‐Looking Information
The information contained herein contains "forward‐looking statements" within the meaning of the United
States Private Securities Litigation Reform Act of 1995 and "forward‐looking information" within the meaning
of applicable Canadian securities legislation. "Forward‐looking information" includes, but is not limited to,
statements with respect to the activities, events or developments that the Company expects or anticipates will
or may occur in the future. Generally, but not always, forward‐looking information and statements can be
identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates",
"forecasts", "intends", "anticipates", or "believes" or the negative connotation thereof or variations of such
words and phrases or state that certain actions, events or results "may", "could", "would", "might" or "will be
taken", "occur" or "be achieved" or the negative connotation thereof.
Forward‐looking information and statements are based on the then current expectations, beliefs, assumptions,
estimates and forecasts about NexGen's business and the industry and markets in which it operates. Forward‐
looking information and statements are made based upon numerous assumptions, including among others,
that the proposed transaction will be completed, the results of planned exploration activities are as anticipated,
the price of uranium, the cost of planned exploration activities, that financing will be available if and when
needed and on reasonable terms, that third party contractors, equipment, supplies and governmental and other
approvals required to conduct NexGen's planned exploration activities will be available on reasonable terms
and in a timely manner and that general business and economic conditions will not change in a material adverse
manner. Although the assumptions made by the Company in providing forward looking information or making
forward looking statements are considered reasonable by management at the time, there can be no assurance
that such assumptions will prove to be accurate.
Forward‐looking information and statements also involve known and unknown risks and uncertainties and
other factors, which may cause actual results, performances and achievements of NexGen to differ materially