IsoEnergy Announces Initial Mineral Resource Estimate for the High-Grade Hurricane Uranium Deposit
IsoEnergy Announces Initial Mineral Resource Estimate for the High-Grade
Hurricane Uranium Deposit
Saskatoon, SK, July 18, 2022 – IsoEnergy Ltd. (“IsoEnergy” or the “Company”) (TSXV: ISO; OTCQX: ISENF)
is pleased to announce the initial independent Mineral Resource Estimate (the “Resource Estimate”) for
the Hurricane uranium deposit on its 100% owned Larocque East project in the eastern Athabasca Basin
of Saskatchewan.
Highlights
• Indicated Mineral Resources of 48.61 million lbs of U3O8 based on 63,800 tonnes grading 34.5%
U3O8, including 43.89 million lbs U 3O8 at an average grade of 52.1% U3O8 within the high -grade
domain
• Inferred Mineral Resources of 2.66 million lbs of U3O8 based on 54,300 tonnes grading 2.2% U3O8
• Indicated Mineral Resources are highly insensitive to cut -off grade due to the high -grade and
compact nature of the Hurricane Deposit (refer Table 2)
Table 1 – Summary of Hurricane Attributable Mineral Resources (as of July 8, 2022)
Notes:
1. CIM (2014) definitions were followed for all Mineral Resource categories.
2. Mineral Resources are estimated at a uranium cut-off grade of 1.00% U3O8.
3. Tonnes are based on bulk density weighting.
4. Mineral Resources are estimated using a long-term uranium price of US$65/lb.
5. Minimum grade width of one metre was applied to the resource domain wireframes.
6. Bulk density was interpolated using values derived from a regression curve based on U 3O8 assay values.
7. Numbers may not add due to rounding.
Category Domain Tonnage
(000 t)
Grade
(% U3O8)
Contained Metal
(Million lb U3O8)
Indicated High-Grade 38.2 52.1 43.89
Medium-Grade 25.6 8.4 4.72
Low-Grade - - -
Indicated Total 63.8 34.5 48.61
Inferred High-Grade - - -
Medium-Grade 4.0 11.2 1.00
Low-Grade 50.3 1.5 1.66
Inferred Total 54.3 2.2 2.66
Table 2 – Hurricane Block Model Sensitivity to Cut-Off Grade (as of July 8, 2022)
Note: Mineral Resources are estimated at a uranium cut off grade of 1.0% U 3O8
Tim Gabruch, President and Chief Executive Officer commented: “Since incorporation by NexGen Energy
in 2016, IsoEnergy’s objective has been to explore for high -grade uranium on the eastern side of
Saskatchewan’s Athabasca Basin. Following the discovery of Hurricane in July 2018 IsoEnergy has focused
on determining the scope and scale of the deposit. The six drilling programs completed since then have
culminated in today’s announcement of an Indicated Mineral Resource of 48.61 million pounds U3O8 at
an average grade of 34.5% U3O8, with the high-grade domain containing nearly 44 million pounds U3O8 at
an average grade of 52.1% U3O8. The team at IsoEnergy is extremely proud of the work done on Hurricane,
and it is rewarding to present this initial Resource Estimate to the Company’s stakeholders.
Hurricane’s exceptionally high uranium grade and relatively shallow depth, together with its proximity to
existing eastern Athabasca Basin road, power and milling infrastructure are key attributes. Saskatchewan
is home to the world’s largest and highest-grade uranium mines and deposits, and it is recognized as the
premier mining jurisdiction in Canada and one of the best globally. For decades it has also been
established as one of the most stable, dependable jurisdictions for the world’s nuclear energy providers
to source uranium. Today, the outlo ok for nuclear energy has never been more positive, with growing
recognition of the vital role it will play in providing clean, baseload energy to help address climate change
challenges globally. IsoEnergy will continue to progress Hurricane with an object ive to meaningfully
contribute to the world’s growing demand for clean nuclear energy.”
Andy Carmichael, Vice President of Exploration commented: “This Mineral Resource Estimate establishes
Hurricane as the world’s newest, very high -grade uranium deposit. On average , one cubic metre of
Hurricane’s high-grade domain weighs over 4.5 tonnes and contains over 5,200 lbs of U3O8. Of the past-
and presently- producing uranium mines in the Athabasca Basin, Hurricane is most analogous to the Cigar
Resource
Category
Cut-off Grade
(% U3O8)
Tonnage
(000 t)
Grade
(% U3O8)
Contained Metal
(Million lb U3O8)
Indicated 0.05 63.8 36. 72 48.61
0.25 63.8 36.72 48.61
0.50 63.8 36.72 48.61
0.75 63.8 36.72 48.61
1.00 63.8 36.72 48.61
2.00 63.8 36.76 48.61
3.00 63.4 36.98 48.58
5.00 60.1 38.75 48.29
10.00 44.1 49.63 45.65
Inferred 0.05 288.2 0.73 4.67
0.25 199.6 0.99 4.37
0.50 124.5 1.37 3.77
0.75 82.3 1.76 3.20
1.00 54.3 2.23 2.66
2.00 11.5 5.57 1.42
3.00 5.1 9.62 1.08
5.00 4.0 11.21 1.00
10.00 2.0 13.42 0.61
Lake deposit at the nearby operating mine with respect to the mineralization’s grade, thickness, width,
style, and the alteration halo and ground conditions which mantle the deposit . Notably, Hurricane’s
Mineral Resource Estimate employs a cut-off grade consistent with uranium Mineral Resource Estimates
reported from Cigar Lake and other operations in the eastern Athabasca Basin.”
Geology and Mineralization
The Hurricane zone measures 375 metres along strike, up to 125 metres wide, and up to 12 metres thick.
The high-grade domain, which contains 43.89 million pounds of U3O8 at an average grade of 52.1% U3O8,
occupies an area 125 metres long and is up to 63 metres wide and up to 4.5 metres thick. Mineralization
at Hurricane occurs at the sub-Athabasca unconformity approximately 325 metres vertically below surface
and is essentially horizontal. East-west trending, steeply north -dipping basement rocks underlying
Hurricane host centimetre - to metre- scale fault zones preferentially occurring at contacts between
graphitic and non-graphitic units. Mineralization is controlled by the intersection of these fault zones with
the sub -Athabasca unconformity resulting mineralization elongated in its east -west dimension.
Mineralization ranges from disseminated to massive and includes very high-grade intersections, including
38.8% over 7.5 metres in LE20-76 between 322.5 and 330 metres which includes a subinterval averaging
74.0% U 3O8 over 3.5 metres from 324.0 to 327.5 metres . Additional Hurricane drilling highlights are
presented in Table 3, including intercepts from high-grade domain.
Drilling, Sampling and Analytical
The Mineral Resource Estimate was defined using 52 diamond drill holes totaling 20,387 metres and using
785 samples. Uranium grade data comprises chemical assays o f half split drill core samples collected on
site by IsoEnergy staff. All samples were assayed at the independent Saskatchewan Research Council (SRC)
Geoanalytical Laboratory of Saskatoon, an ISO/IEC 17025 accredited facility. Samples were analysed using
a combination of inductively coupled plasma - mass spectrometry (ICP-MS), inductively coupled plasma -
optical emission spectrometry ( ICP-OES), and partial or total acid digestion of one aliquot of
representative sample pulp per analysis. Mineralized samples were analysed for U3O8 by ICP-OES. Quality
Assurance and Quality Control (QA/QC) measures include the field insertion of Certified Reference
Material (CRM) standards, CRM blanks, and duplicate samples. The Mineral Resource Estimate grade data
was obtained only from chemical assays; no radiometric data were utilized.
Estimation Methodology
Mineral Resources were estimated by SLR Consulting (Canad a) Ltd. (SLR), an independent consulting
company experienced in completing uranium Mineral Resource estimates in the Athabasca Basin and
worldwide.
Wireframe models of mineralized zones were used to constrain the block model grade interpolation
process. The models represent grade envelopes using the geological interpretation described above as
guidance. The wireframes consisted of Low -Grade (LG), Medium -Grade (MG), and High- Grade (HG)
domains at nominal cut-off grades (COG) of 0.05%, 5.0%, and 25.0% U3O8, respectively (Figures 1 and 2).
Sample intervals with assay results less than the nominated COG were included within the mineralized
wireframes if the core length was less than two metres or allowed for modelling of grade continuity. Hard
domain boundaries were employed to prevent assay results from one domain influencing the remaining
domains.
Statistical evaluation of samples from each domain was completed separately to determine the treatment
of high-grade assays. No capping was applied to the High-Grade domain; assays were capped at 5.0% U3O8
and 20.0% U3O8 within the Low- and Medium-Grade domains, respectively. High grade x density threshold
value of 250 (approximately equivalent to 55% U3O8) spatial restrictions equal to half the parent search
ellipse dimensions were utilized within the High-Grade domain.
The uranium grade was used to estimate the density of each sample using polynomial formula developed
by SLR from the results of 115 samples analyzed for bulk density and uranium grade. Densities were then
interpolated into the block model to convert minera lized volumes to tonnage and were also used to
weight the uranium grades interpolated into each block.
Blocks were classified as Indicated or Inferred based on drill hole spacing, confidence in the geological
interpretation, and apparent continuity of mineralization. All the blocks within the HG domains and blocks
within the MG domain with apparent grade continuity from two or more holes were classified as
Indicated. For the LG grade domain, blocks that did not meet the criteria of grade x thickness (GT) greater
or equal to 1.0%m were removed from the Mineral Resource reporting . The block model was validated
using s wath plots of composite grades versus inverse distance cubed , ordinary kriging, and nearest
neighbour grades in the X, Y, and Z dimensions, volumetric comparison of blocks versus wireframes, visual
inspection of block versus composite grades on plan, vertical, and long section, and statistical comparison
of block grades and assay composite grades.
Table 3 – Selected Drilling Results from the Hurricane Deposit
LE20-30 329.5 334.5 5.0 7.8 180/-80 442.0 Section 4460E Mineralized
incl. 332.0 333.0 1.0 34.9 HG Domain Intercept
LE20-32A 329.5 339.0 9.5 17.5 180/-80 470.0 Section 4510E Mineralized
incl. 334.5 337.0 2.5 63.6 HG Domain Intercept
LE20-34 325.5 334.0 8.5 33.9 180/-80 461.0 Section 4435E Mineralized
incl. 328.0 332.5 4.5 62.1 HG Domain Intercept
LE20-40 319.5 326.0 6.5 12.6 000/-90 368.0 Section 4435E Mineralized
incl. 323.0 324.5 1.5 53.8 HG Domain Intercept
LE20-51 322.0 330.0 8.0 13.6 000/-90 341.0 Section 4510E Mineralized
incl. 326.5 329.0 2.5 38.4 HG Domain Intercept
LE20-52 318.5 326.0 7.5 22.7 000/-90 365.0 Section 4435E Mineralized
incl. 322.5 324.5 2.0 79.2 HG Domain Intercept
LE20-53 317.5 328.0 10.5 11.7 000/-90 374.0 Section 4410E Mineralized
incl. 325.0 327.5 2.5 44.7 HG Domain Intercept
LE20-54 329.5 337.5 8.0 14.4 180/-79 428.5 Section 4510E Mineralized
incl. 333.5 337.0 3.5 28.1 HG Domain Intercept
LE20-57 343.3 350.3 7.0 16.6 217/-70 413.3 Section 4435E Mineralized
incl. 347.3 349.3 2.0 52.6 HG Domain Intercept
LE20-62 321.0 325.5 4.5 6.2 000/-90 350.0 Section 4435E Mineralized
incl. 324.5 325.5 1.0 18.5 HG Domain Intercept
LE20-64 322.5 329.0 6.5 37.6 000/-90 412.5 Section 4535E Mineralized
incl. 324.5 329.0 4.5 54.2 HG Domain Intercept
LE20-68 320.0 334.0 14.0 5.5 180/-80 470.0 Section 4485E Mineralized
incl. 332.0 333.5 1.5 49.3 HG Domain Intercept
LE20-72 320.5 326.5 6.0 6.2 000/-90 398.0 Section 4460E Mineralized
incl. 325.0 326.0 1.0 27.8 HG Domain Intercept
LE20-76 322.5 330.5 8.0 36.4 000/-90 359.0 Section 4435E Mineralized
incl. 323.5 327.5 4.0 71.7 HG Domain Intercept
LE21-78C11 248.0 260.0 12.0 5.2 000/-90 323.0 Section 4460E Mineralized
incl. 257.5 258.5 1.0 42.4 HG Domain Intercept
LE21-107 324.5 332.0 7.5 17.7 000/-90 344.0 Section 4485E Mineralized
incl. 327.5 331.0 3.5 34.5 HG Domain Intercept
Notes:
All results previously disclosed
1: LE21-78C1 is a wedged offcut from LE21-78 at 70m
Location NoteHole-ID From
(m)
To
(m)
Length
(m)
Hole Length
(m)
Azimuth/Dip
(degrees)
Chemical Assays
(% U3O8)
Figure 1 – Plan view of Mineralized Domains with Selected Drilling Results
Figure 2 – Cross Section 4435E Showing High-, Medium-, and Low-Grade Domains with Drilling Results
Figure 3 - IsoEnergy Athabasca Projects