REG - Aura Energy Limited - Aura increases Tiris' Mineral Resources by 55%
12/06/2024 07:30
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RNS Number : 1146S Aura Energy Limited 12 June 2024
12 June 2024
Aura increases Tiris' Mineral Resources by 55%
to 91.3 Mlbs U(3)O(8)
Resource growth adds confidence in future expansion and scale opportunities
KEY POINTS:
• Tiris' global Mineral Resources increased by 55% to 91.3 Mlbs
U(3)O(8), up from 58.9Mlbs U(3)O(8) 1 (#_ftn1) (global Mineral Resources
includes Tiris East and Oum Ferkik Project areas)
• The recent 15,262m drill program delivered a very large 28.9 Mlbs
U(3)O(8) increase in the Tiris East Uranium Project's Mineral Resources,
totalling 76.6 Mlbs U(3)O(8), delivered at a discovery cost of only US$ 0.14
per lb U(3)O(8)
• Measured and Indicated Mineral Resources increased by 35% adding
10.3 Mlbs U(3)O(8) providing further confidence to the Front End Engineering
Design ("FEED") 2 (#_ftn2) production schedule
• Drilling results and the increase in Mineral Resources both
demonstrate significant future resource growth potential at Tiris from ongoing
exploration activities
• The major increase in the Tiris Mineral Resources:
o Reinforces Auras' commitment to progress Tiris towards a development
decision in late 2024 or early 2025;
o Offers significant potential to materially enhance the already excellent
FEED economics of NPV(8) US$ 388 M and IRR 36% after tax 3 (#_ftn3) , 4
(#_ftn4) ,, and
o Presents real opportunities to increase the Project's future scale beyond
the current 17-year mine life at 2 Mlbs pa U(3)O(8) production
• Additional Mineral Resources were defined from extensions to known
mineralisation and exhibit the same characteristics as the current shallow
free digging mineralisation that has proven exceptional beneficiation
characteristics
• Mine scheduling and optimisation including a review of the Ore
Reserve Estimate will now be undertaken on the enhanced Mineral Resources
Aura Energy's Managing Director and CEO Andrew Grove said:
"The resource growth at Tiris confirms our view that this is an important
uranium province with the capacity for further growth upside.
The Board believes that the very significant increase in Mineral Resources
resulting from the successful drilling campaign will have a materially
positive impact on Tiris' economics and has been delivered at a very low
discovery cost of just US$ 0.14 per lb.
Mineralisation was identified not only from high strength radiometric
anomalies, but from areas of low strength anomalies, significantly increasing
the exploration potential of the area as these low-level anomalies have been
ignored in past exploration.
More opportunities remain to expand the known mineralisation within the
current granted tenements. In addition, the potential for future discoveries
within the 13,000km(2) of new tenement applications is significant as we have
only just begun exploration over this district-scale opportunity.
The increased Mineral Resource inventory will further support the funding and
development of the Tiris Uranium Project in the near future."
Tiris Global Mineral Resource Estimate as at June 2024
Area Class Mt Grade ppm U(3)O(8) Mlbs U(3)O(8)
Tiris East Measured 34 230 17.3
Indicated 48 212 22.6
Inferred 79 210 36.7
Total 162 215 76.6
Oum Ferkik Inferred 22 294 14.6
Total Mineral Resources Measured 34 230 17.3
Indicated 48 212 22.6
Inferred 102 229 51.4
Total 184 225 91.3
Tiris Global Mineral Resource Estimate reported using a 100ppm U(3)O(8)
cut-off grade, see Table 1 for details
Aura Energy Limited (ASX: AEE, AIM: AURA) ("Aura" or "the Company") is pleased
to provide an update on the Mineral Resource Estimate ("MRE") for the Tiris
Uranium Project ("Tiris" or the "Project") in Mauritania.
The drilling program undertaken in 2024 has delivered a major increase to the
Project's Global Mineral Resources totalling 184 Mt at 225ppm for 91.3 Mlbs
U(3)O(8) at a 100ppm cut-off grade. This is a 55% increase in the contained
U(3)O(8) from the previous MRE, reported in 2023, of 113Mt at 236ppm for
58.9Mlbs 5 (#_ftn5) U(3)O(8).
This drilling program was aimed at assessing additional resource potential at
Tiris East and delivered a 10.3 Mlbs or 35% increase of Measured and Indicated
("M&I") Resources, which stands at 83 Mt @ 219ppm for 39.9 Mlbs U(3)O(8,)
and a 76% increase in total Inferred Resource, which stands at 102 Mt @ 229ppm
for 51.4 Mlbs U(3)O(8.) The detail of the upgraded resource across the project
areas and the previous resources are shown in Table 1.
In April 2024 6 (#_ftn6) , Aura completed an air core ("AC") drilling program
of 2,995 holes for 15,262 metres, a 37% increase in the total number of holes
available for resource calculations, to evaluate a previously announced
exploration target of between 8 Mlbs and 32 Mlbs 7 (#_ftn7) . The Mineral
Resource increase of 32.4 Mlbs U(3)O(8) exceeded the upper end of the
exploration target range, providing strong support to Aura's exploration
methodology, and is a strong indication to the mineralisation potential that
may be available in regional leases that are currently under application 8
(#_ftn8) .
In addition to targeting extensions to known mineralisation, and testing
previously un-drilled radiometric anomalies around Tiris East, the program
considered several conceptual targets over low-level radiometric anomalies.
Several of these conceptual targets returned very positive results, further
increasing exploration potential of the area. This is a major change from
previous exploration in the area.
Mineral Resource estimates were undertaken utilising Multiple Indicator
Kriging ("MIK") estimation methodology and recoverable Mineral Resources
reported using a 10x10x1m Selective Mining Unit ("SMU"). The Competent Person
for the 2024 Tiris Mineral Resource Estimates is Mr Arnold van der Heyden of
H&S Consulting Pty Limited ("HSC").
Figure 1 - Location of the Tiris Uranium Project, Mauritania
Figure 2 shows radiometrics, tenement boundaries, Prospect locations, resource
boundaries reported in 2024 and 2023, along with drilling completed during the
current and prior programs
Figure 3. Oum Ferkik, showing radiometrics, tenement boundaries, 2024 resource
boundary (100ppm cut) and the resource boundary calculated in 2011 along with
drill hold locations
MRE June 2024 MRE Feb 2023 % Change
Deposit Class Mt U(3)O(8) Mlb U(3)O(8) V(2)O(5) ppm Mlb V(2)O(5) Mt U(3)O(8) Mlb U(3)O(8) V(2)O(5) ppm Mlb V(2)O(5) Mt Mlb U(3)O(8)
Hippolyte East Inferred 2 172 0.8 56 0.3 no previous estimate N/A N/A
Hippolyte North Measured 11 237 5.6 77 1.8 8 236 4.2 76 1.3 35 35
Indicated 7 238 3.7 77 1.2 6 217 2.8 70 0.9 24 32
Inferred 9 236 4.9 77 1.6 5 212 2.2 69 0.7 100 123
Sub-total 27 237 14.3 77 4.6 19 224 9.1 73 3.0 48 57
Hippolyte South Indicated 5 205 2.1 67 0.7 5 192 2 62 0.6 2 5
Inferred 28 181 11 59 3.6 3 176 1.1 57 0.3 926 900
Sub-total 32 184 13.2 60 4.3 7 186 3 60 1.0 336 340
Hippolyte West C Inferred 4 244 2.2 79 0.7 8 310 5.6 100 1.8 70 34
Marie Inferred 10 246 5.3 80 1.7
Lazare North Measured 4 291 2.4 94 0.8 1 282 0.6 91 0.2 280 300
Indicated 10 247 5.3 80 1.7 10 229 5.1 74 1.6 -4 4
Inferred 4 299 2.4 97 0.8 4 210 1.7 68 0.6 0 41
Sub-total 17 268 10.1 87 3.3 15 228 7.4 74 2.4 16 36
Lazare South Measured 8 234 4.4 76 1.4 9 233 4.4 76 1.4 -2 0
Indicated 7 217 3.1 70 1.0 5 226 2.6 73 0.8 27 19
Inferred 6 209 2.6 68 0.8 5 222 2.3 72 0.8 19 13
Sub-total 21 222 10.1 72 3.3 19 228 9.3 74 3.0 11 9
Sadi Measured 11 198 4.9 64 1.6 12 189 4.8 61 1.6 -3 2
Indicated 20 187 8.4 61 2.7 7 200 3.2 65 1.0 174 163
Inferred 17 201 7.5 65 2.4 10 228 5.2 74 1.7 64 44
Sub-total 48 195 20.8 63 6.7 29 206 13.2 67 4.3 66 58
All Tiris East Measured 34 230 17.3 75 5.6 29 218 14 71 4.5 18 24
Indicated 48 212 22.6 69 7.3 33 215 15.6 70 5.1 46 45
Inferred 79 210 36.7 68 11.9 35 237 18 77 5.8 130 104
Sub-total 162 215 76.6 69 24.9 97 224 47.7 73 15.4 68 61
Oum Ferkik Inferred 22 294 14.6 95 4.7 16 305 11.2 99 3.6 37 30
All Deposits Measured 34 230 17.3 74 5.6 29 218 14 71 4.5 18 24
Indicated 48 212 22.6 69 7.3 33 215 15.6 70 5.1 46 45
Inferred 102 229 51.4 74 16.6 51 261 29.2 85 9.4 100 76
Grand Total All 184 225 91.3 73 29.6 113 236 58.9 77 19.0 63 55
Table 1 - Comparison of Tiris Global Mineral Resource Estimate (totals may
vary slightly due to rounding), both Feb'23 and Jun'24 MRE were reported using
a 100ppm U(3)O(8) cut-off
Tiris Uranium Project Summary
The Tiris Uranium Project is in north-eastern Mauritania, approximately
1,200km northeast of the capital, Nouakchott. Access is via Zouérat, 744 km
by bitumen road and then a further ~700km on hardpan desert roads (Figure 1).
The Mineral Resource Estimate ("MRE") is based on drilling conducted on two
Mineral Exploration permits held 100% by Aura Energy: 562B4 Oum Ferkik, 2365B4
Oued EL Foule Sud, and on two Exploitation permits: 2492C4 Oued El Foule,
2491C4 Ain Sder held by Tiris Ressources SA (85% Aura Energy). Oum Ferkik is
under application for conversion to an Exploitation Permit.
Global Mineral Resources at Tiris currently stand at 184Mt at 225ppm for
91.3Mlbs U(3)O(8 ) , including Measured and Indicated Resources of 83Mt @
219ppm for 39.9Mlbs U(3)O(8 )and Inferred Resource of 102Mt @ 229ppm for
51.4Mlbs U(3)O(8 )(applying a 100ppm U(3)O(8) cut-off grade)(.)
The recently released FEED 9 (#_ftn9) study defined a near-term low-cost 2
Mlbs U(3)O(8) pa uranium project with a 17-year mine life and very strong
economics; NPV(8) US$ 388 M, IRR 36% and 2.5 year pay-back at a US$80/lb
U(3)O(8) price. The Project has significant optionality in the design,
allowing expansion to expand to accommodate growth in Mineral Resources. The
Tiris East Mineral Resources are very shallow (less than six metres deep),
free dig mineralisation, with no crushing or grinding that has proven
exceptional beneficiation characteristics which gives rise to Tiris' robust
economics.
Regional Geological Setting
The Tiris Uranium Project lies in the north-eastern part of the Reguibat
Craton, an Archaean (>2.5 Ga) and Lower Proterozoic (1.6-2.5 Ga) aged
complex composed principally of granitoids, meta-sediments and meta-volcanics
(Figure 4). The resources lie within Proterozoic portions of the craton. This
part of the craton generally consists of intrusive and high-grade metamorphic
rocks of amphibolite facies grade. In addition to the Archaean and
Paleoproterozoic basement rocks, two principal types of Cainozoic surficial
sediments occur; Hamada (sand and outwash fan material) and Cailloutis (flat
lying calcrete layers, typically 1 to 3 metres thick, in places partially
silicified) which in this area stand out as small mesas up to a few metres
above the surrounding land surface. Several small uranium occurrences were
known in the Reguibat Craton from exploration during the 1950's.
Figure 4: Regional geology of Mauritania; red stars are Aura uranium resources
All the resource zones are generally at less than 5m depths lie beneath flat
land surfaces covered by surficial hamada and thin aeolian sand deposits
(Figure 5). This shallow overburden largely covers the basement rocks, which
only appear as scattered outcrops.
Figure 5: Typical landscape within Tiris project area, trench illustrating
soft sandy overburden with gravelly free digging calcrete ore generally less
than 6 metres deep.
Uranium Mineralisation
The uranium resources generally lie either within weathered, partially
decomposed red granite or in colluvial gravels developed on or near red
granites. Small portions occur in other rock types such as meta-volcanics and
meta-sediments. The resources are believed to have developed within shallow
depressions or basins, either within weathered granitic rocks or where
colluvial material has accumulated in desert sheet wash events. The pebbles
within the gravels are generally unweathered fragments washed in from the
nearby exfoliating granites and other crystalline rocks, mixed with sand,
silt, calcrete, gypsum and yellow uranium vanadates. The gravels and weathered
granite occur at surface or under a very thin (<30 cm) veneer of wind-blown
sand and form laterally continuous, single, thin sheets overlying fresh rock,
usually granite. The uranium mineralisation generally forms thin shallow
horizontal tabular bodies ranging in thickness from 1 to 12 m hosted in
weathered granite and granitic sediments.
It is inferred that the deposits were formed by near-surface leaching of
uranium from the uraniferous red granites by saline groundwaters during the
wet Saharan "pluvial" periods. There have been several periods over the past
2.5 million years, the most recent ending only 5,900 years ago. Evaporation
during the subsequent arid periods caused the precipitation of uranium
vanadates, along with calcium, sodium and strontium carbonates, sulphates and
chlorides.
The host material at Tiris is granitic gravel or weathered granite containing
powdery calcium carbonate (calcrete) and sulphates. Although the Tiris
mineralisation is associated with calcium carbonates, it differs from other
well-known calcrete uranium deposits such as Langer Heinrich and Yeelirrie, in
that they are river valley-fill deposits. The Tiris deposits have formed in
shallow depressions in unconsolidated and uncemented gravels and in partially
decomposed granites. In Namibia and Western Australia, the mineralisation is
typically within calcareous clays or massive hard calcrete which forms below
the water table, often at several levels related to the changing positions of
the water table. In contrast, Aura's Tiris deposits are believed to be
pedogenic calcrete occurrences that formed in the vadose zone by capillary
action above the permanent water table.
The uranium mineralisation occurs principally as carnotite
K(2)(UO(2))(2)(VO(4))(2).3H(2)O) and possibly some of the chemically-similar
calcium uranium vanadate, tyuyamunite Ca(UO(2))(2)(VO(4))(2).5-8H(2)O) in
varying proportions. In this report, "carnotite" refers to any mineral in the
carnotite-tyuyamunite series. The carnotite occurs as fine dustings and
coatings on granite or granite mineral fragments, and on the surfaces or
partly within the calcite cement that forms the patches of calcrete. The
carnotite is mostly ultrafine, micron scale in grain size. The carnotite is
distributed erratically in numerous patches and strings over short distances.
Twelve prospect areas have been identified in Tiris East and were drilled in
this program (Figure 2). Of these, eleven prospects returned economic
resources, grouped into eight MRE's (Table 1). The four Marie Prospects
(E,F,G,H) have been grouped into one MRE. A further MRE was completed over Oum
Ferkik (previously referred to as Tiris West), despite no new drilling being
completed, so that the resource estimation methods are consistent with that
used at Tiris East. The form of mineralisation in each MRE is as follows:
1. The Sadi MRE occurs in an irregular NNW trending area with a north-south
length of 10.6km and an average east-west extent of ~3.0km. There are a few
smaller patches of mineralisation outside the main zone. The MRE starts at
surface and extends to a maximum depth of 17m below surface, although the
majority of mineralisation occurs within 8m of surface.
2. The Lazare North MRE occurs over an area of 4.8km east-west and averages
~2.0km north-south. It comprises two main areas with an additional small patch
in the north-west. The MRE starts at surface and extends to a maximum depth of
12m below surface, although the majority of mineralisation occurs within 7m of
surface.
3. The Lazare South MRE occurs over an area of 7.8km east-west and averages
~1.5km north-south. It comprises two main areas with an additional smaller
patch to the east. The MRE starts at surface and extends to a maximum depth of
19m below surface, although the majority of mineralisation occurs within 6m of
surface.
4. The Hippolyte North MRE occurs as multiple lenses over an area of 6.1km
east-west and 9.6km north-south and was divided into 7 separate zones for
grade estimation. The MRE starts at surface and extends to a maximum depth of
11m below surface, although the majority of mineralisation occurs within 6m of
surface.
5. The Hippolyte South MRE occurs as multiple lenses over an area of 8.0km
east-west and 9.2km north-south and was divided into 5 separate zones for
grade estimation. The MRE starts at surface and extends to a maximum depth of
9m below surface, although the majority of mineralisation occurs within 6m of
surface.
6. The Hippolyte East MRE occurs as four separate lenses over an area of 3.8km
east-west and 4.3km north-south and was divided into three separate zones for
grade estimation. The MRE starts at surface and extends to a maximum depth of
8m below surface, although the majority of mineralisation occurs within 5m of
surface.
7. The Hippolyte West C MRE occurs as a single irregular zone over an area of
3.6km north-south and averages ~1.3km east-west. The MRE starts at surface and
extends to a maximum depth of 10m below surface, although the majority of
mineralisation occurs within 7m of surface.
8. The Marie MRE occurs as four separate zones (E, F, G, H) over an area of
~12km east-west and ~7.5km north-south. Marie E extends 1.8km N-S and 0.6km
E-W; Marie F is 1.8km N-S and 0.75km E-W; Marie G is 1.5km N-S and 2.0km E-W;
and Marie H is 4.0km N-S and 0.6km E-W. The MRE starts at surface and extends
to a maximum depth of 9m below surface, although the majority of
mineralisation occurs within 6m of surface.
The Oum Ferkik area comprises two separate deposits, grouped into one MRE,
within a rectangle around 3.4km north-south and 7.2km east-west.
9. The Oum Ferkik K MRE occurs as a single irregular zone over an area with
maximum dimensions of 2.6km north-south and 2.4km east-west. The MRE starts at
surface and extends to a maximum depth of 11m below surface, although the
majority of mineralisation occurs within 6m of surface.
10. The Oum Ferkik L MRE occurs as a single irregular zone over an area with
maximum dimensions of 2.9km north-south and 1.9km east-west. The MRE starts at
surface and extends to a maximum depth of 11m below surface, although the
majority of mineralisation occurs within 6m of surface.
These dimensions do not account for sand dunes that overlay parts of some
deposits. The models account for sand dunes that overlie mineralisation in
places and can be over 10m high. These dunes move on an annual basis within
specific corridors. AEE provided the outlines of the base of sand dunes from
aerial imagery and H&S Consulting generated volumes based on a nominal
height of 10m. The modelling of these volumes and their location is somewhat
subjective, but it does give a nominal indication of the location of the sand
dune corridors.
Drilling techniques, hole spacing and mapping
Approximately 7,944 drill holes were used in this Resource Estimate using
predominantly air core drilling, with small diamond drilling programs in 2017
and 2022 utilising triple tube PQ core allowing grade estimation by both
chemical analysis and downhole gamma logging for validation purposes. In
approximately 76% of these, U(3)O(8) grade was determined by downhole gamma
logging with disequilibrium factor applied, and in the remainder (44%),
U(3)O(8) grade was determined by chemical assay. Table 2 presents the drilling
metres undertaken on the project, broken down by drilling and sampling methods
and year of completion.
Year Total Holes Total meters Aircore PQ core Assay Samples Gamma surveys
Holes Metres Holes Metres Samples Number of holes
2010/2011 1457 6650 1370 6202 6241
2012 423 2487 423 2289 3000
2017 1487 8190 1428 7872 59 318 626 1481
2022 1669 10955 1604 10531 66 430 819 1668
2024 2995 15262 2995 15262 2992
Total 8031 43543 7820 42155 125 748 10686 6141
Table 2. Drilling quantity and method, along with sampling method per year on
the Tiris Project for holes included in this MRE.
In most cases, Measured Resources are based on 50m x 50m spaced drill holes,
Indicated Resources are based on 100m x 100m spaced holes, and Inferred
Resources on 100m x 200m spaced holes. For the 2022 drilling, the drill
spacing for Measured Resources was undertaken at 50m x 50m or 70m by 70m
spacing. In 2017, three 100m x 100m squares were drilled at 12.5m hole spacing
in both N-S and E-W directions to investigate grade anisotropy. In 2022, a
further two such detailed patterns were drilled. Variography constructed by
the resource consultants confirmed that the drill spacings are appropriate for
the Resource classifications. In 2024, drilling assessed potential for
Inferred mineralisation so drilling began on initial wide-spaced programs and
was closed into 200m x 100 m collar spacing to achieve coverage required for
at least Inferred resources.
The uranium mineralisation is flat lying to sub-horizontal so vertical holes
were drilled, intersecting the mineralisation at a high angle. The collars are
spaced in a grid pattern to provide adequate coverage of the mineralisation.
The mineralisation sits within sediment and weather rock, and while most areas
have very limited outcrop, some zones such as Hippolyte North had a
significant amount of outcrop. In some areas this outcropping material can be
soft, weathered and contain visible carnotite, but most outcrops are of very
hard granitic material, so are unlikely to be mineralised and not amenable to
be dug freely. To account for solid outcrop in the resource statements,
geological outcrop mapping was undertaken in the field by Aura geologists for
a small portion of the work and, where adequate field data was not available,
the outcrop was digitised from Worldview 3-HD Satellite Imagery to 15cm
resolution provided by Geoimage Pty Ltd. Three versions of the outcrop map
were produced (that were based upon different interpretations of the imagery)
so the effect of three amounts of outcrop upon the resource was assessed.
Given that the drillholes are already very shallow in the areas of outcrop,
there was not a significant different in the results after applying the three
different interpretations of imagery. The middle-case outcrop scenario was
used for the MRE. Field investigations will be undertaken in the future to
determine fact-check the digitised plans.
Logging and Sampling
A summary of sampling methods is presented in Table 2. Prior to 2017, analysis
of mineralisation was undertaken using chemical assay from chip samples.
Sampling in 2009 was from reverse circulation drilling, but due to excessive
sample loss, these results were not used in any MRE's. Sampling in 2010, 2011,
2012 and 2015 were from AC chips but the 2015 was also found to suffer from
sample loss, so subsequent programs relied on downhole geophysical methods in
AC holes, supported by chemical assays/downhole geophysics from PQ diamond
core. The samples from 2015 were not included in the MRE and most areas
covered by these holes were redrilled and surveyed with downhole gamma.
For drilling programs prior to 2017, all drilled material provided by the AC
rig was collected in its entirety in 1m intervals except for the first metre
which was sampled in 0.5m intervals. All intervals were geologically logged.
AC drill cuttings were riffle split on-site to extract samples for assay. PQ
diamond drill core lengths were measured to an accuracy of ~1cm immediately on
removal from the core barrel to determine and record core recovery. After
transportation to the core yard in Nouakchott, depths were marked on the core
at 1-metre intervals and recovery data was checked again. Assays taken from
the PQ core were compared against downhole gamma information from the same
hole. Table 1 in the appendices contains all material information to
understand the estimates of Mineral Resources.
For holes drilled from 2017 onwards, uranium concentrations were measured by
downhole total count gamma logging, which was converted to equivalent uranium
grades (eU(3)O(8)) by applying calibration information, an air correction and
minor smoothing. A check was undertaken on the disequilibrium between U(238)
and its gamma-emitting daughter products. To test for radioactive
disequilibrium, 343 pulped-core samples were sent to Australian Nuclear
Science and Technology Organisation ("ANSTO"). Results were compiled and
interpreted by D Wilson of 3D Exploration. Disequilibrium factors were
produced in two different ways. The first was based on laboratory measurements
made at ANSTO, which resulted in a disequilibrium factor of 1.29. The second
was a comparison of drill core assay results against downhole gamma logging
resulting in a conversion factor of 1.16. When the apparent underestimation of
grade by ICP analysis (in comparison to the more accurate DNA analysis) by 7%
is taken into consideration the drill hole assay data imply a conversion
factor of 1.24. Aura personnel decided a disequilibrium factor of 1.25 was
appropriate and applied this to convert raw gamma eU(3)O(8) grades to U(3)O(8)
grades.
Downhole geological logging on AC holes was traditionally undertaken only in
the final metre, which was washed and stored in chip trays, to determine the
rock character at end of hole. This process continued in 2024, except the
upper portion of the hole was also logged from photos. Full logs were
completed for PQ core holes. Differentiation of the weathered granite from
granitic sediments is unreliable from air-core sample returns.
Year Total Holes Total meters Aircore Number of holes Geologically logged (greater than 75%) Number of holes geologically logged (final metre)
Holes Metres
2010/2011 1457 6650 1370 6202 1452 1402
2012 523 2487 423 2289 523 523
2017 1487 8190 1428 7872 1486 57
2022 1669 10955 1604 10531 1518 425
2024 2995 15262 2995 15262 2882 2862
Table 3. Proportion of holes geologically logged per program
Sample analysis and Quality Assurance and Quality Control ("QAQC")
2011/12 AC drill samples were submitted to Stewart Laboratories sample
preparation facility near Zouérat in Mauritania. Samples were crushed by jaw
crusher to -12mm and 1kg was riffle split for pulverising to +85% passing 75
microns. An ~100g split was bagged and sent to Stewart Laboratories in Ireland
for analysis by pressed pellet XRF. Previous analysis comparing different
analytical methods (XRF, ICP, DNC) had indicated that XRF is an accurate
method on this material, if an x-ray band is selected for measurement that is
not affected by the presence of strontium, and this was done. This method will
measure total uranium.
The drill core was cut in half longitudinally by a diamond saw. For each
half-metre of core, half-core was bagged for assay. This task was completed in
2017 by ALS Laboratories and in 2022 by MMM Laboratories in Nouakchott, under
the supervision of an Aura Geologist. Bagged ½ core samples were prepared by
ALS Laboratories Nouakchott by Method Prep 22 (Crush to 70% less than 6mm,
pulverize entire sample to better than 85% passing 75 microns). A 100g sample
of pulp was split off using a mini-riffle splitter. For diamond core drilled
in 2022, sample preparation was completed by MMM Laboratories in Nouakchott,
using the same method as for the 2017 core samples, except the 100g sample of
pulp was split off using rotary splitter. Sample pulps were forwarded by air
to ALS in Ireland for uranium analysis by ALS Method U-MS62 (U by ICP-MS after
four-acid digestion) which provides near total extraction. ROL-21 agitation
was carried out on the pulps before selecting assay aliquot.
For the 2017, 2022 and 2024 programs, downhole gamma logging was performed by
2 down-hole Auslog gamma sondes utilising an A075 Natural Gamma Tool. Drill
holes were gamma logged as soon as possible after drilling to avoid radon
build-up. Each borehole was logged in both directions to verify consistency.
Logging speed was 2 metres per minute, with a sample interval of 1cm. At least
one hole was re-logged after each 20 holes as a repeatability check. A
reference hole was established and relogged every 2 days as a check on
consistency. Gamma logging procedures & interpretation were supervised by
consultant David Wilson who qualifies as a Competent Person in these matters.
For the assayed sample, duplicates, blanks, and standards were inserted in the
assay sample stream at regular intervals. QAQC procedures for the 2011/12 AC
drilling involved submission of 1 QAQC sample in every 5 samples, comprised
of: field duplicates every twelve samples, blanks every 31 samples, umpire
assays every 11 samples, certified reference material every 129 samples.
Umpire analysis was carried on 427 sample intervals. For each of these, the
original pressed pellet XRF sample assayed by Stewart Labs was re-assayed by
ICP at Stewart Labs. Each of these samples was also assayed by XRF and by ICP
at ALS Labs. Accuracy & precision were within acceptable limits. QAQC
procedures for the 2017 and 2022 diamond drilling comprise, submission of one
standard, blank and field duplicate every 25 samples. In each set of 25
samples, a blank was inserted at every tenth position, standard at every
twentieth position and field duplicate every 25th position. Accuracy &
precision were within acceptable limits.
Specific Gravity measurements.
Dry bulk density of diamond drill core samples was measured at the ALS
facility in Nouakchott using an immersion method (Archimedes principle) on
selected PQ diamond drill core intervals ranging in size from 10cm to 30cm.
Competent pieces of drill core were selected on a nominal interval of 50cm.
The samples chosen are believed to be representative of the surrounding rock
type. All density samples are wrapped in cling film to avoid water absorption.
A total of 412 density measurements have been taken from drill core at the
Tiris deposits with values ranging from 1.50 to 2.66t/m3 and averaging
2.13t/m3.
Measured density values show that there is a reasonable correlation between
density and the depth of the sample. A regression was used to assign densities
to each block in the block models based on depth below surface.
Geological Interpretation
The interpretation of the mineralisation as flat lying tabular bodies is
undisputed. The lateral extents of the mineralisation are poorly defined and
recent drilling around the edges of the deposits shows that mineralisation is
not necessarily limited to areas with stronger surface radiometric anomalies.
The continuity of both grade and geology are affected by the extent of
weathering of the granitic host. Continuity does not appear to be affected by
faulting. The extent of outcrop/subcrop and its relationship to free-digging
mineralisation is somewhat uncertain but a conservative approach has been
taken to minimise this risk. Alternative interpretations of the geology are
unlikely to significantly impact estimated resources.
Modelling was undertaken to generate surfaces representing the base of the
mineralisation at each deposit in order to limit the extrapolation of grades
into volumes that have no data. This is important at Tiris as there is a
general decrease in uranium grades with depth. These basal surfaces generally
represent the top of fresh granite, where air-core drilling could penetrate no
further. The basal surfaces were produced using the locations of the end of
the deepest assay from each drill hole. Most AC holes were drilled using a
blade, to refusal, so the end of hole generally represents the base of
weathering. The exceptions are the 2022 air-core drilling, when a hydraulic
hammer was used instead of a conventional blade bit, and all diamond core
holes. Therefore, these holes could penetrate fresh rock, while the blade bit
used in other years could not. This difference is important to the Tiris
project because the DFS assumes that mining will be free-digging.
Consequently, fresh rock intersected in the 2022 air-core holes and all
diamond core drilling will not be mineable under current assumptions and needs
to be excluded from the MRE. Therefore, in deposits with 2022 air-core holes
and diamond core drilling (Sadi, Lazare South and Hippolyte North), an
additional surface was created to represent the top of fresh rock, which may
be shallower than the base of mineralisation in places. The material logged as
fresh in descriptions of either regolith, weathering or oxidation was not
material but was nonetheless excluded from the MRE.
Areas of obvious outcrop were excised from the MRE assuming a dip of 45
degrees between weathered granite/granitic sediments and the fresh granite.
At the time that the estimates were completed, no topographic survey data were
available. The majority of the recent drill collar locations were surveyed
using a Differential Global Positioning System (DGPS). HSC used the locations
of all drill hole collars that had been located with the DGPS to create a
wireframe representing the topographic surface. The elevations of all drill
holes that had been located using a handheld GPS were then derived from this
topographic surface.
All geological models contain block proportions of material:
• Below topography
• Above base of mineralisation
• Above top of fresh rock
• Above top of holes
These proportions were later combined to assess estimates of material between
the different surfaces.
The block proportion below topography was used to assign average block depth,
which was used to calculate dry bulk density and allow assessment of
mineralisation in one metre slices below surface.
Estimation and classification methodology
New estimates were generated for all deposits reported here, determined by
H&S Consultants Pty Limited ("HSC"). There is significant additional
recent drilling for all the Tiris East deposits, while Tiris West was
re-estimated with existing historical data using the same methodology as Tiris
East to make all estimates consistent and compatible.
Uranium concentration was estimated by recoverable Multiple Indicator Kriging
("MIK") using GS3 geostatistical software. The uranium grades at the Tiris
deposits exhibit a positively skewed distributions and therefore show
reasonable sensitivity to a small number of high grades. MIK is considered an
appropriate estimation method for the uranium grade distribution at the Tiris
deposits because it specifically accounts for the changing spatial continuity
at different grades through a set of indicators variograms at a range of grade
thresholds. It also reduces the need to use the practice of top cutting.
All drill hole intervals were composited to 0.5m for estimation. No direct
top-cuts were applied but the average of the mean and median grades was
applied to the top indicator class to address any potential extreme values.
The larger deposits were subdivided into a number of subzones for estimation,
with conditional statistics generated for each of the subzones. All class
grades used for estimation of the mineralised domains were derived from the
class mean grades, except the top indicator class.
The base of mineralisation surface was used to limit the extrapolation of
grades into volumes that had no data. The proportion of outcrop was estimated
for each block based on digitising provided by AEE and used to deplete the MRE
on the assumption that this material cannot be dug freely.
Vanadium is a potential by-product and vanadium oxide (V(2)O(5)) has been
estimated for the mineral resources using the stoichiometric V(2)O(5)/U(3)O(8)
ratio for carnotite group minerals. These V(2)O(5) values represent
potentially recoverable vanadium in carnotite and not total vanadium occurring
in mineralisation, which is significantly higher in almost all cases. These
potentially recoverable V(2)O(5) values are based on the analysis of a
substantial database of available sample data and represent average values
that may be conservative. This procedure relies on the correlation between
uranium and vanadium in carnotite group minerals, which are the only
uranium-vanadium minerals identified to date at Tiris.
The recoverable MIK technique employed by HSC in this case requires a set of
14 variogram models, one for each of the fourteen grade thresholds used. Sets
of variogram models were created for the major Subzones and were applied to
subzones that did not have sufficient data to generate reliable models.
Drill hole spacing varies from 50x50m or 70x70m in the better drilled
deposits, out to 100x200m in the less well drilled deposits.
Sample length varies by assay type and year. Earlier chemical assays
(2009-2012) are typically 1.0m in length, apart from 0.5m intervals for the
first metre in each hole. Later (2017-2022) chemical assays are consistently
0.5m in length. All raw radiometric data (one-centimetre readings) has been
composited to regular 0.5m intervals. All drill hole grade data were
composited to nominal 0.5m intervals for analysis and estimation.
The block dimensions were 50x50m in plan-view and 1m vertically. The plan
dimensions were chosen as it is the nominal drill hole spacing (preferable for
MIK estimation). The vertical dimension was chosen to reflect the anisotropy
of the mineralisation and the downhole data spacing.
The minimum selective mining unit size is assumed to be 10x10x0.5m.
A three-pass search strategy was used to estimate the U(3)O(8) grades at each
of the deposits. Each pass required a minimum number of samples with data from
a minimum number of octants of the search ellipse to be populated.
Discretisation was set to 5x5x2 points in X, Y and Z, respectively. The search
criteria are shown below. The last short axis of the search ellipse is
vertical. The maximum distance of extrapolation of the reported estimates from
drill hole data points is limited to around 220m.
80x80x2.0m search, 16-48 samples, minimum 4 octants
160x160x2.0m search, 16-48 samples, minimum 4 octants
240x240x3.0m search, 8-48 samples, minimum 2 octants
HSC validated the models statistically using histograms, boxplots, scatter
plots and summary statistics. No independent check estimates were produced but
the new models were compared to previous estimates and found to be consistent
and compatible. The new MRE takes appropriate account of previous estimates.
Classification is based on the search pass used to estimate the block. In some
cases, the blocks at surface were populated in a later search pass than blocks
immediately below, as these blocks did not meet the minimum search criteria
due to the fact that there are no samples above the topography. In order to
alleviate this, the minimum search pass from a column of blocks was propagated
upwards.
Pass one nominally equates to Measured Resources, pass two translates to
Indicated Resources and Pass three equates to Inferred Resources.
In deposits drilled entirely at 100x200m hole spacing, the entire resource was
classified as Inferred, regardless of estimation pass, to maintain consistency
with previous estimates.
A small number of estimated model blocks occur outside the current AEE leases,
and these were excluded from the reported MRE.
Reason for difference in resource quantity and modifying factors due to Mining
and Metallurgical Parameters
The drilling undertaken in Tiris East this year represents an approximate 37%
increase in the number of holes drilled into the resource. Given that the
previous resources included areas that had been drilled in a much denser
pattern, this percentage understates the actual surface area of resource
drilled. The area of MRE covered in 2023 was 39km(2), while the current MRE
covers 85km(2), so the current MRE has a surface area approximately 2.2 times
the size of the 2023 MRE. The increase in contained metal (Mlbs U(3)O(8)) is a
factor of 1.3 (from 60.6 to 76.6 Mlbs).
The MRE at Oum Ferkik presents an increase in resource tonnage despite having
no additional drilling in that Prospect. The contained metal has changed from
11.2 to 14.6 Mlbs U(3)O(8), presenting a 3.4 Mlb increase. Surface area
increased from 2.9 to 6.5 km(2). This increase can be attributed to several
factors:
1. This (2024) resource estimation was undertaken utilising MIK, while
the earlier model used ordinary kriging ("OK"). The OK method used a 100ppm
boundary on the resource, so is considered to be conditionally biased, given
there is no natural hard geological boundary at the 100ppm limit.
Mineralisation does continue outside of the drill pattern and, with the spotty
grades, is not sufficiently assessed to close off the boundary.
2. Holes or intervals with no data that were previously not assayed due
to failing a sample screening process were not included at all in the previous
modelling. With the generation of new data, we have been able to show that the
sample screening method used historically was not accurate, and these holes
may indeed be mineralised. A low-grade value was assigned to these holes and
they were included in the MRE.
3. Both OK and MIK both used 50x50m mining blocks, but MIK assumed a
10x10m selective mining unit ("SMU") while effectively the OK model had an SMU
of 50x50m. This means that in the OK model, 10x10m areas that are above 100ppm
but surrounded by lower grade material would have been diluted by lower grade
material, and potentially excluded from the contained tonnage. This highlights
the need for effective consideration of mining parameters in the resource
estimate.
All of the resources reported here have been estimated on the assumption that
the deposits will be mined by open-pit and free digging, with no blasting or
crushing. Recoverable MIK includes block support correction to account for the
change from sample size support to the size of a mining block. This process
requires an assumed grade control drill spacing and the assumed size of the
SMU. The variance adjustment factors were estimated from the U(3)O(8) metal
variogram models assuming a minimum SMU of 10x10x0.5m (east, north, vertical)
with high quality grade control sampling on a 10x10x0.5m pattern (east, north,
vertical).
Internal dilution within the SMUs is accounted for by the estimation method;
external mining dilution and other mining recovery factors are not included in
the estimates. If a larger SMU size or a broader grade control drill pattern
is implemented, then the selectivity assumed in the reported resources may not
be realised.
The FEED Study 10 (#_ftn10) completed in February 2024 indicates that the
Tiris deposits are amenable to a free digging mining operations without the
need for crushing and grinding, and ore beneficiation will deliver a
high-grade leach feed. A cut-off grade of 100ppm was selected due to the
upgrade indicated by the metallurgical testwork. The Enhanced Definitive
Feasibility Study 11 (#_ftn11) completed in March 2023 declared an Ore
Reserve Estimate at a 110ppm U(3)O(8,) so the current resource cut-off grade
is considered appropriate.
ENDS
The Board of Aura Energy Ltd has approved this announcement.
This Announcement contains inside information for the purposes of the UK
version of the market abuse regulation (EU No. 596/2014) as it forms part of
United Kingdom domestic law by virtue of the European Union (Withdrawal) Act
2018 ("UK MAR").
For further information, please contact:
Andrew Grove Paul Ryan SP Angel Corporate Finance LLP
Managing Director and CEO Morrow Sodali Nominated Advisor and Broker
Aura Energy Limited Investor & Media Relations David Hignell
agrove@auraee.com (mailto:Agrove@auraee.com) p.ryan@morrowsodali.com (mailto:p.ryan@morrowsodali.com) Kasia Brzozowska
+61 414 011 383 +61 409 296 511 Grant Barker
+44 203 470 0470
About Aura Energy (ASX: AEE, AIM: AURA)
Aura Energy is an Australian-based mineral company with major uranium and
polymetallic projects in Africa and Europe.
The Company is focused on developing a uranium mine at the Tiris Uranium
Project, a major greenfield uranium discovery in Mauritania. The February 2024
FEED study demonstrated Tiris to be a near-term low-cost 2 Mlbs U(3)O(8) pa
near term uranium mine with a 17-year mine life with excellent economics and
optionality to expand to accommodate resource growth.
Aura plans to transition from a uranium explorer to a uranium producer to
capitalise on the rapidly growing demand for nuclear power as the world shifts
towards a decarbonised energy sector.
Beyond the Tiris Project, Aura owns 100% of the Häggån Project in Sweden.
Häggån contains a global-scale 2.5Bt vanadium, sulphate of potash ("SOP")
and uranium resource. Utilising only 3% of the resource, a 2023 Scoping Study
outlined a 27-year mine life based on mining 3.5 Mtpa.
Disclaimer Regarding Forward-Looking Statements
This ASX announcement (Announcement) contains various forward-looking
statements. All statements other than statements of historical fact are
forward-looking statements. Forward-looking statements are inherently subject
to uncertainties in that they may be affected by a variety of known and
unknown risks, variables and factors which could cause actual values or
results, performance or achievements to differ materially from the
expectations described in such forward-looking statements. The Company does
not give any assurance or guarantee that the anticipated
results, performance or achievements expressed or implied in those
forward-looking statements will be achieved.
Notes to Project Description
The Company confirms that the material assumptions underpinning the Tiris
Uranium Production Target and the associated financial information derived
from the Tiris production target as outlined in the Aura Energy release dated
28 February 2024 for the Tiris FEED study continue to apply and have not
materially changed.
The Company confirms that it is not aware of any new information or data that
materially affects the information included in the relevant market
announcement and that all material assumptions and technical parameters
underpinning the estimates in the relevant market announcements continue to
apply and have not materially changed.
Concerning the Resource statements, there is a low level of geological
confidence associated with the inferred mineral resource and there is no
certainty that further exploration work will result in the determination of
indicated measured resource or that the production target will be realised.
Competent Persons
The Competent Person for the 2024 Tiris Mineral Resource Estimates for all
deposits is Mr Arnold van der Heyden of H&S Consulting Pty Limited. The
information in the report to which this statement is attached that relates to
the 2024 Mineral Resource Estimate is based on information compiled by Mr van
der Heyden. Mr van der Heyden has sufficient experience that is relevant to
the resource estimation to qualify Mr van der Heyden as a Competent Person as
defined in the 2012 edition of the 'Australasian Code for Reporting of
Exploration Results, Mineral Resources and Ore Reserves'. Mr van der Heyden is
an employee of H&S Consultants Pty Limited, a Sydney based geological
consulting firm. Mr van der Heyden is a Member and Chartered Professional of
The Australasian Institute of Mining and Metallurgy ("AusIMM") and consents to
the inclusion in the report of the matters based on his information in the
form and context in which it appears.
The Competent Person for drill hole data and for integrating the different
resource estimates from September 2022 to [December 2023] is Dr Michael
Fletcher. The information in the report to which this statement is attached
that relates to compiling resource estimates and to drill hole data is based
on information compiled by Dr Michael Fletcher. Dr Fletcher has sufficient
relevant experience in the preparation and compilation of exploration data
across a broad range of deposits to qualify as a Competent Person as defined
in the 2012 edition of the 'Australasian Code for Reporting of Exploration
Results, Mineral Resources and Ore Reserves'. Dr Fletcher is a consultant to
Aura Energy and a full-time employee of GeoEndeavours Pty Ltd. Dr Fletcher is
a Member of the Australasian Institute of Geoscientists and consents to the
inclusion in the report of the matters based on his information.
The Competent Person for drill hole data and for integrating the different
resource estimates prior to September 2022 is Mr Neil Clifford. The
information in the report to which this statement is attached that relates to
compiling resource estimates and to drill hole data is based on information
compiled by Mr Neil Clifford. Mr Clifford has sufficient experience that is
relevant to the style of mineralisation and type of deposit under
consideration and to the activity which he is undertaking to qualify Mr
Clifford as a Competent Person as defined in the 2012 edition of the
'Australasian Code for Reporting of Exploration Results, Mineral Resources and
Ore Reserves'. Mr Clifford is a consultant to Aura Energy. Mr Clifford is a
Member of the Australasian Institute of Geoscientists. Mr Clifford consents to
the inclusion in the report of the matters based on his information.
The Competent Person for interpreting downhole gamma information,
disequilibrium analysis and assay results is Mr David Wilson. Mr Wilson has
sufficient experience that is relevant to the style of mineralisation and type
of deposit under consideration and to the activity which he is undertaking to
qualify as a Competent Person as defined in the 2012 edition of the
'Australasian Code for Reporting of Exploration Results, Mineral Resources and
Ore Reserves'. Mr Wilson is a consultant to Aura Energy and is a full-time
employee of 3D Exploration. Mr Wilson is a Member of the Australasian
Institute of Geoscientists and consents to the inclusion in the report of the
matters based on his information.
APPENDIX 1
JORC Code 2012
Table 1 Appendix 5A ASX Listing Rules
Section 1 Sampling Techniques and Data
(Criteria in this section apply to all succeeding sections)
Criteria JORC Code explanation Commentary
Sampling techniques · Nature and quality of sampling (e.g. cut channels, random chips, or
specific specialised industry standard measurement tools appropriate to the
minerals under investigation, such as down hole gamma sondes, or handheld XRF · 7 field sampling programs have been completed, with data
instruments, etc). These examples should not be taken as limiting the broad from 5 of these used for this MRE, as shown in the following table:
meaning of sampling.
Year Total Holes Total meters Aircore RC PQ core Assay Samples Gamma surveys
Holes Metres Holes Metres Holes Metres Samples Number of holes
· Include reference to measures taken to ensure sample representivity 2009 305 1704 305 1704 1004 74
and the appropriate calibration of any measurement tools or systems used. 2010/2011 1457 6650 1370 6202 87 448 6241
2012 423 2487 423 2289 3000
· Aspects of the determination of mineralisation that are Material to 2015 582 3313 582 3313 3966
the Public Report. 2017 1487 8190 1428 7872 59 318 626 1481
2022 1669 10955 1604 10531 66 430 819 1668
· In cases where 'industry standard' work has been done this would be 2024 2995 15262 2995 15262 2992
relatively simple (e.g. 'reverse circulation drilling was used to obtain 1 m Total 7844 43543 7820 42155 87 448 125 748 10686 6141
samples from which 3 kg was pulverised to produce a 30 g charge for fire
assay'). In other cases, more explanation may be required, such as where there
is coarse gold that has inherent sampling problems. Unusual commodities or
mineralisation types (eg submarine nodules) may warrant disclosure of detailed · Drill spacing of 200 by 100m is generally required for
information. inferred resources, 50 by 100m for indicated resources, and 50 by 50m for
measured resources.
· Drill results showed questionable sample return in the RC
drilling, and the 2015 AC program so data from those programs was not included
in this MRE. Most areas covered by those programs have been redrilled. After
2015, the main sampling method was downhole geophysical logging of AC holes,
supported by PQ core drilling with downhole geophysical logging and chemical
assay.
· For the programs from 2015 and earlier, AC drill cuttings
were riffle split on site to extract approx. 2 kg samples for assay for the
downhole intervals 0 to 0.5m, 0.5 to 1.0m, 1 to 2m, & thereafter in 1m
intervals to end of hole.
· Down hole gamma logging in 2017, 2022 and 2024 was by 2
down-hole Auslog gamma sondes operated by Poseidon Geophysics (Pty) Ltd based
in Gaborone Botswana using 3 geophysicists employed by Poseidon geophysics.
Quality control was managed by David Wilson from 3D Exploration.
· The 2 sondes (serial numbers T093 and T272) were sent to
the Department of Environment, Water & Natural Resources, Adelaide South
Australia for calibration prior to the surveys in both 2017 and 2022.
· Mapping of outcrops was undertaken in field programs of
2015, 2018, 2022 and 2024. Most outcrop mapping was included in large areas of
scree and float so was of limited use for resource modelling. Although many
outcrop areas are hard and probably unmineralized (and not available for
free-dig and current treatment plan), some areas are weathered granite (as
seen in metallurgical pit programs). Outcrop maps were mostly constructed from
digitising satellite imagery (Worldview 3-HD Satellite Imagery to 15cm
resolution provided by Geoimage Pty Ltd), with reference to aircore drilling
depths to determine what part of the image were probably outcrop. This work
needs to be field checked during later work.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, rotary · AC drilling in all programs prior to 2022 was conducted
air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or by Wallis Drilling of Perth WA using a Mantis drill rig with NQ size bit
standard tube, depth of diamond tails, face-sampling bit or other type, (outer diameter 75.7mm) except for the 2015 program which used HQ size bit (OD
whether core is oriented and if so, by what method, etc). 96mm). Diamond drilling (DD) was carried out by Capital Drilling Mauritanie
SARL utilising triple tube PQ coring (122.6mm outer diameter bit, 85mm
diameter core).
· In 2022, AC drilling was conducted by Sahara Natural
Resources (Guinea) using a 650 model DTH cum-rotary rig. PQ triple-tube
diamond drilling was conducted by Tayssir Drilling.
· The 2024 AC drilling program was conducted by Sahara
Natural Resources using their purpose- built SNR SAC15 multi-wheel drive rig.
Drill sample recovery · Method of recording and assessing core and chip sample recoveries and · For the 2010, 2011, 2012 Aircore programs, no sample
results assessed. recovery information is available.
· Measures taken to maximise sample recovery and ensure representative · 2015 AC drilling the total drill return for each sample
nature of the samples. interval was bagged and weighed to an accuracy of approximately 0.25kg to
estimate sample recovery. The assay results for the 2015 drilling are
· Whether a relationship exists between sample recovery and grade and considered inaccurate due to loss of fine uranium-bearing carnotite during the
whether sample bias may have occurred due to preferential loss/gain of drilling process, on the basis of 63 holes which were later gamma logged which
fine/coarse material. indicated that eU3O8 grades were approx. 3 times greater than assay grades.
Between 2015 and 2023, 35% (205) of the 2015 collars had another hole drilled
within 15 metres and a downhole gamma survey undertaken.
· Efforts were made to minimise dust loss, eg in most holes
the first metre was drilled without applying compressed air, and thereafter
minimum air necessary to lift the sample was applied. In view of the ultrafine
grain size of the uranium mineral carnotite, even where high recoveries were
recorded, it is possible that some carnotite was lost in dust emitted from the
drill rig cyclone. resulting in underestimation of uranium grade
· For PQ core, given the ultra-fine-grained nature of the
carnotite mineralisation, loss of uranium is likely in any core runs recording
less than 100% recovery, and even where 100% recovery is recorded it is
possible some loss of carnotite may have occurred.
· 2017, 2022, 2024 AC drillholes were not physically
sampled, and downhole gamma surveys were completed for grade measurement.
· All drill core was transported in covered core trays to
Nouakchott for geological logging, density determination, and core cutting.
· Drill core lengths were measured to an accuracy of c. 1cm
immediately on removal from the core barrel to determine & record core
recovery. After transportation to the core yard in Nouakchott, the depths were
marked on the core at 1 metre intervals and recovery data was checked again.
81% of core samples have a recovery of 95% or greater, and 85% of core samples
have a recovery of 90% or greater.
Logging · Whether core and chip samples have been geologically and · In 2011/12/15 AC drilling each sample interval was
geotechnically logged to a level of detail to support appropriate Mineral geologically logged by an onsite geologist and drill logs were uploaded to
Resource estimation, mining studies and metallurgical studies. Aura's database managed by Reflex Hub in Perth. A sample of sieved &
washed chips for each sample interval was retained in chip trays for
· Whether logging is qualitative or quantitative in nature. Core (or reference. In 2017 and 2022 AC drilling, only the bottom hole sample was
costean, channel, etc) photography. geologically logged, and a sample retained in chip trays.
· The total length and percentage of the relevant intersections logged. · In 2024 drilling, all holes were geologically logged,
mostly from photographs, with logging limited to weathering, presence of
carnotite, and rock type. The last sample from each hole was washed and
retained in chip trays. The amount of lithological logging completed in each
drilling program is shown in the following Table:
Year Total Holes Total meters Number of holes Geologically logged (greater than 75%) Number of holes geologically logged (final metre)
2009 305 1704 305 294
2010/2011 1457 6649.55 1452 1402
2012 523 2486.90 523 523
2015 582 3312.50 582 581
2017 1487 8189.77 1486 57
2022 1669 10955.04 1518 425
2024 2995 15262.09 2882 2862
· Drill core was photographed, geologically logged and logs
were recorded on Aura's logging template and uploaded to Aura's database.
· A total of 559 density samples have been taken. In
2011/12/17 drilling, 385 density measurements (which included 25 duplicate
determinations) were taken on drill core by ALS Laboratories in Nouakchott
under the supervision of Aura's geologist. In 2022, 174 density measurements
were taken on drill core by MMM Laboratories SARL in Nouakchott, under the
supervision of an Aura geologist.
· Database management was undertaken by Reflex Hub in Perth
prior to July 2019, and by Earth SQL in Melbourne after that date.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core · 2010/2011/12/15 AC drill samples were riffle split on
taken. site to provide a minimum 2kg sample for assay and a duplicate split for
reference and possible umpire analysis.
· If non-core, whether riffled, tube sampled, rotary split, etc and
whether sampled wet or dry. · Duplicates, blanks, and standards were inserted in the
assay sample stream at regular intervals as detailed in the next section.
· For all sample types, the nature, quality and appropriateness of the
sample preparation technique. · Drill core from 2017 was cut in half longitudinally by
diamond saw by ALS Laboratories after marking up by, and under the supervision
· Quality control procedures adopted for all sub-sampling stages to of, an Aura geologist. This task was completed in 2022 by MMM Laboratories in
maximise representivity of samples. Nouakchott, under the supervision of an Aura geologist.
· Measures taken to ensure that the sampling is representative of the · For each half-metre of core, half-core was bagged for
in-situ material collected, including for instance results for field assay.
duplicate/second-half sampling.
· Given the fine-grained nature of the uranium minerals
· Whether sample sizes are appropriate to the grain size of the these sample sizes are appropriate.
material being sampled.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and · 2010/2011/12 AC drill samples were submitted to Stewart
laboratory procedures used and whether the technique is considered partial or Laboratories sample preparation facility near Zouérat in Mauritania (In 2012
total. Stewart Laboratories became part of ALS Laboratories). Samples were crushed by
jaw crusher to -12mm and 1kg was riffle split for pulverising to +85% passing
· For geophysical tools, spectrometers, handheld XRF instruments, etc, 75 microns. An c. 100g split was bagged and sent to Stewart Laboratories in
the parameters used in determining the analysis including instrument make and Ireland for analysis by pressed pellet XRF. Previous analysis comparing
model, reading times, calibrations factors applied and their derivation, etc. different analytical methods (XRF, ICP, DNC) had indicated that XRF is an
accurate method on this material, if an x-ray band is selected for measurement
· Nature of quality control procedures adopted (eg standards, blanks, that is not affected by the presence of strontium, and this was done. This
duplicates, external laboratory checks) and whether acceptable levels of method will measure total uranium.
accuracy (i.e. lack of bias) and precision have been established.
2015 AC drill samples were submitted to ALS Laboratories sample preparation
facility in Nouakchott Mauritania. Samples were crushed by jaw crusher to
-12mm and 1kg was riffle split for pulverising to +85% passing 75 microns. An
c. 100g split was bagged and sent to ALS Global in Ireland for analysis by ALS
method MC-ICP61 after 4-acid digestion. This method will measure near total
uranium.
· For diamond core drilled in 2017, bagged ½ core was
prepared by ALS Laboratories Nouakchott by Method Prep 22 (Crush to 70% less
than 6mm, pulverize entire sample to better than 85% passing 75 microns). An
c. 100g sample of pulp was split off using mini-riffle splitter, placed in
sample envelope and forwarded by air to ALS in Ireland for uranium analysis by
ALS Method U-MS62 (U by ICP-MS after 4 acid digestion). 4 acid digestion
provides near total extraction.
· For diamond core drilled in 2022, sample preparation was
completed by MMM Laboratories in Noakchott. Samples were crushed to 70% less
than 6mm, pulverize entire sample to better than 85% passing 75 microns. An c.
100g sample of pulp was split off using rotary splitter, placed in sample
envelope and forwarded by air to ALS in Ireland for uranium analysis by ALS
Method U-MS62 (U by ICP-MS after 4 acid digestion). ROL-21 agitation was
carried out on the pulps before selecting assay aliquot. 4 acid digestion
provides near total extraction.
· Downhole gamma logging was performed by 2 down-hole
Auslog gamma sondes comprising:
§ DLS5 Winch Controller
§ W600-1 12V Portable Winch
§ A075 Natural Gamma Tool
· Logging procedures involved:
§ Drill holes were gamma logged as soon as possible after drilling to
avoid radon build-up.
§ Each borehole logged in both directions to verify consistency.
§ Logging speed: 2 metres per minute
§ Sampling interval: 1cm
§ At least one hole was re-logged after each 20 holes as a repeatability
check.
§ A reference hole was established and relogged every 2 days as a check
on consistency.
§ Gamma logging procedures & interpretation were supervised by
consultant David Wilson who qualifies as a Competent Person in these matters.
· QAQC procedures for the 2011/12 AC drilling comprised, on
average:
§ Field duplicates assays: 1 in every 12 samples
§ Blanks: 1 in every 31 samples
§ Umpire assays: 1 in every 11 samples
Umpire analysis was carried on 427 sample intervals. For each of these the
original pressed pellet XRF sample assayed by Stewart Labs was re-assayed by
ICP by Stewart Labs. Each of these samples was also assayed by XRF and by ICP
by ALS Labs.
§ Certified Reference material: 1 in every 129 samples
§ Total QAQC samples: 1 in every 5 samples
Accuracy & precision were within acceptable limits.
· QAQC procedures for the 2017 and 2022 diamond drilling
comprise, submission of one standard, blank and field duplicate every 25
samples. In each set of 25 samples, a blank was inserted at every tenth
position, standard at every twentieth position and field duplicate every
25(th) position.
· 190 sample pulps sent to ANSTO Minerals at Lucas Heights
for U determination by Delayed Neutron Count, serving as the Umpire analysis.
· Certified reference standards at 128, 264, and 550ppm
were purchased from African Mineral Standards, South Africa. Blanks were
prepared from sand collected near the University of Nouakchott, that had been
scanned with a hand-held spectrometer.
Verification of sampling and assaying · The verification of significant intersections by either independent · Excluding the 2009 and 2015 programs, ie for all drilling
or alternative company personnel. included in this MRE, 7945 holes were drilled in total. Of these, 7820 were
aircore, and 125 were PQ diamond core. Approximately 76 % of holes were
· The use of twinned holes. surveyed using downhole gamma, while diamond drillholes were both gamma logged
and chemically assayed for validation purposes. The holes drilled in 2009 and
· Documentation of primary data, data entry procedures, data 2015 were excluded from all resource estimates and this report (887 holes).
verification, data storage (physical and electronic) protocols.
· To test for radioactive disequilibrium 343 samples were
· Discuss any adjustment to assay data. sent to Australian Nuclear Science and Technology Organisation (ANSTO) in
Australia for equilibrium determinations. Results were compiled and
interpreted by D Wilson of 3D Exploration. Disequilibrium factors were
produced in two different ways. The first was based on laboratory measurements
made at ANSTO, which suggested a disequilibrium factor of 1.29. The second was
comparison of drill core assay results against downhole gamma logging which
suggested a conversion factor of 1.16. When the apparent under estimation of
grade by ICP analysis (in comparison to the more accurate DNA analysis) by 7%
is taken into consideration the drill hole assay data imply a conversion
factor of 1.24. Aura personnel decided a disequilibrium factor of 1.25 was
appropriate and applied this to convert eU3O8 grades to U3O8 grades. A factor
of 1.25 needs to be applied to all raw gamma grades to provide the correct U
grade. All drillhole data recorded was uploaded to Aura's online database
managed by Reflex Hub during the programs prior to July 2019 and managed by
Earth SQL after that date. Analyses were forwarded directly from the
laboratories to the database manager for incorporation in the database.
Location of data points · Accuracy and quality of surveys used to locate drill holes (collar · 2010/2011/12 drillhole collars were surveyed by handheld
and down-hole surveys), trenches, mine workings and other locations used in GPS. According to Garmin, 90% of handheld GPS coordinates should fall within
Mineral Resource estimation. 15m accuracy for modern hand-held GPS units.
· Specification of the grid system used. · All 2017, 2022, and 2024 drillhole collars were surveyed
by differential surveying conducted by IRC-Magma (ISO 9001-2015) to an
· Quality and adequacy of topographic control. accuracy of +/- 20cm in all dimensions.
· In 2024, Survey was undertaken prior to demobilisation of
the on-site geological staff, and checks were undertaken to ensure all DGPS
surveys fell within 15.2 metres of the hand-held gps. Any questionable holes
were re-surveyed before demobilisation.
· The grid projection used is UTM WGS84 Zone 29N.
· An independent check comparing data gathered prior to
2022 to topography was undertaken by PhotoSat of Vancouver, using satellite
data provided to an accuracy of +/- 20cm, confirming the quality and adequacy
of topographic control.
Data spacing and distribution · Data spacing for reporting of Exploration Results. · In most cases Measured Resources are based on 50m x 50m
spaced drillholes, Indicated Resources are based on 100m x 100m spaced holes,
· Whether the data spacing, and distribution is sufficient to establish and Inferred Resources on 100m x 200m spaced holes.
the degree of geological and grade continuity appropriate for the Mineral
Resource and Ore Reserve estimation procedure(s) and classifications applied. · Downhole gamma data was composited into 0.5m intervals.
· Whether sample compositing has been applied. · Three 100m x 100m areas were drilled at 12.5m spacing in
both N-S & E-W directions for geostatistical purposes and to examine
variability. Resource modelling, estimation and classification was done by the
independent resource consultants.
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · In 2017, three 100m x 100m squares were drilled at 12.5m
possible structures and the extent to which this is known, considering the hole spacing in both N-S and E-W directions to investigate grade anisotropy.
deposit type. This indicated a weak NW-SE trend to the mineralisation. The drilling pattern
employed is considered appropriate for the mineralisation orientation. In
· If the relationship between the drilling orientation and the 2022, a further two such detailed patterns were drilled.
orientation of key mineralised structures is considered to have introduced a
sampling bias, this should be assessed and reported if material. · The calcrete mineralisation is flat lying to
sub-horizontal so vertical holes were drilled, intersecting the mineralisation
at a high angle.
· The collars are spaced in a grid pattern so provide
adequate coverage of the mineralisation, demonstrating a broad NW-SE linearity
to the mineralisation, with some internal areas running NE-SW.
Sample security · The measures taken to ensure sample security. · Sample collection was supervised by geologists. Samples
were transported as soon as practicable to independent sample preparation
facilities.
· The core samples were transported to the processing
facility in Nouakchott where they were logged, and sample selection was
undertaken by geologists. The core trays were then transported to MMM
laboratories in Nouakchott for cutting, sampling and sample preparation. The
pulped samples were sent to ALS Ireland for analysis.
· Approximately 76% of drillholes in the Tiris Project
(East and West) were surveyed by downhole gamma logging and for these, sample
security is not relevant.
Audits or reviews · The results of any audits or reviews of sampling techniques and data. · A site inspection was conducted by Oliver Mapeto of
Coffey Mining in 2012. A resource report from 2012 was independently reviewed
and confirmed by Wardell Armstrong International in 2016. A Resource Estimate
at Sadi was done in 2021 by Oliver Mapeto acting then as an independent
consultant. The 2018, 2023 and 2024 Mineral Resource Estimates have been
carried out by independent consulting group H&S Consultants Pty Ltd. All
of these consulting groups have reviewed and endorsed the sampling, grade
estimation and QAQC procedures. Dr Michael Fletcher from GeoEndeavours Pty
Ltd. undertook a field inspection in July 2022. Arnold van der Heyden from
H&S Consultants, undertook a field inspection in January 2024.
· Drill spacing of 200 by 100m is generally required for
inferred resources, 50 by 100m for indicated resources, and 50 by 50m for
measured resources.
· Drill results showed questionable sample return in the RC
drilling, and the 2015 AC program so data from those programs was not included
in this MRE. Most areas covered by those programs have been redrilled. After
2015, the main sampling method was downhole geophysical logging of AC holes,
supported by PQ core drilling with downhole geophysical logging and chemical
assay.
· For the programs from 2015 and earlier, AC drill cuttings
were riffle split on site to extract approx. 2 kg samples for assay for the
downhole intervals 0 to 0.5m, 0.5 to 1.0m, 1 to 2m, & thereafter in 1m
intervals to end of hole.
· Down hole gamma logging in 2017, 2022 and 2024 was by 2
down-hole Auslog gamma sondes operated by Poseidon Geophysics (Pty) Ltd based
in Gaborone Botswana using 3 geophysicists employed by Poseidon geophysics.
Quality control was managed by David Wilson from 3D Exploration.
· The 2 sondes (serial numbers T093 and T272) were sent to
the Department of Environment, Water & Natural Resources, Adelaide South
Australia for calibration prior to the surveys in both 2017 and 2022.
· Mapping of outcrops was undertaken in field programs of
2015, 2018, 2022 and 2024. Most outcrop mapping was included in large areas of
scree and float so was of limited use for resource modelling. Although many
outcrop areas are hard and probably unmineralized (and not available for
free-dig and current treatment plan), some areas are weathered granite (as
seen in metallurgical pit programs). Outcrop maps were mostly constructed from
digitising satellite imagery (Worldview 3-HD Satellite Imagery to 15cm
resolution provided by Geoimage Pty Ltd), with reference to aircore drilling
depths to determine what part of the image were probably outcrop. This work
needs to be field checked during later work.
Drilling techniques
· Drill type (eg core, reverse circulation, open-hole hammer, rotary
air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or
standard tube, depth of diamond tails, face-sampling bit or other type,
whether core is oriented and if so, by what method, etc).
· AC drilling in all programs prior to 2022 was conducted
by Wallis Drilling of Perth WA using a Mantis drill rig with NQ size bit
(outer diameter 75.7mm) except for the 2015 program which used HQ size bit (OD
96mm). Diamond drilling (DD) was carried out by Capital Drilling Mauritanie
SARL utilising triple tube PQ coring (122.6mm outer diameter bit, 85mm
diameter core).
· In 2022, AC drilling was conducted by Sahara Natural
Resources (Guinea) using a 650 model DTH cum-rotary rig. PQ triple-tube
diamond drilling was conducted by Tayssir Drilling.
· The 2024 AC drilling program was conducted by Sahara
Natural Resources using their purpose- built SNR SAC15 multi-wheel drive rig.
Drill sample recovery
· Method of recording and assessing core and chip sample recoveries and
results assessed.
· Measures taken to maximise sample recovery and ensure representative
nature of the samples.
· Whether a relationship exists between sample recovery and grade and
whether sample bias may have occurred due to preferential loss/gain of
fine/coarse material.
· For the 2010, 2011, 2012 Aircore programs, no sample
recovery information is available.
· 2015 AC drilling the total drill return for each sample
interval was bagged and weighed to an accuracy of approximately 0.25kg to
estimate sample recovery. The assay results for the 2015 drilling are
considered inaccurate due to loss of fine uranium-bearing carnotite during the
drilling process, on the basis of 63 holes which were later gamma logged which
indicated that eU3O8 grades were approx. 3 times greater than assay grades.
Between 2015 and 2023, 35% (205) of the 2015 collars had another hole drilled
within 15 metres and a downhole gamma survey undertaken.
· Efforts were made to minimise dust loss, eg in most holes
the first metre was drilled without applying compressed air, and thereafter
minimum air necessary to lift the sample was applied. In view of the ultrafine
grain size of the uranium mineral carnotite, even where high recoveries were
recorded, it is possible that some carnotite was lost in dust emitted from the
drill rig cyclone. resulting in underestimation of uranium grade
· For PQ core, given the ultra-fine-grained nature of the
carnotite mineralisation, loss of uranium is likely in any core runs recording
less than 100% recovery, and even where 100% recovery is recorded it is
possible some loss of carnotite may have occurred.
· 2017, 2022, 2024 AC drillholes were not physically
sampled, and downhole gamma surveys were completed for grade measurement.
· All drill core was transported in covered core trays to
Nouakchott for geological logging, density determination, and core cutting.
· Drill core lengths were measured to an accuracy of c. 1cm
immediately on removal from the core barrel to determine & record core
recovery. After transportation to the core yard in Nouakchott, the depths were
marked on the core at 1 metre intervals and recovery data was checked again.
81% of core samples have a recovery of 95% or greater, and 85% of core samples
have a recovery of 90% or greater.
Logging
· Whether core and chip samples have been geologically and
geotechnically logged to a level of detail to support appropriate Mineral
Resource estimation, mining studies and metallurgical studies.
· Whether logging is qualitative or quantitative in nature. Core (or
costean, channel, etc) photography.
· The total length and percentage of the relevant intersections logged.
· In 2011/12/15 AC drilling each sample interval was
geologically logged by an onsite geologist and drill logs were uploaded to
Aura's database managed by Reflex Hub in Perth. A sample of sieved &
washed chips for each sample interval was retained in chip trays for
reference. In 2017 and 2022 AC drilling, only the bottom hole sample was
geologically logged, and a sample retained in chip trays.
· In 2024 drilling, all holes were geologically logged,
mostly from photographs, with logging limited to weathering, presence of
carnotite, and rock type. The last sample from each hole was washed and
retained in chip trays. The amount of lithological logging completed in each
drilling program is shown in the following Table:
Year Total Holes Total meters Number of holes Geologically logged (greater than 75%) Number of holes geologically logged (final metre)
2009 305 1704 305 294
2010/2011 1457 6649.55 1452 1402
2012 523 2486.90 523 523
2015 582 3312.50 582 581
2017 1487 8189.77 1486 57
2022 1669 10955.04 1518 425
2024 2995 15262.09 2882 2862
· Drill core was photographed, geologically logged and logs
were recorded on Aura's logging template and uploaded to Aura's database.
· A total of 559 density samples have been taken. In
2011/12/17 drilling, 385 density measurements (which included 25 duplicate
determinations) were taken on drill core by ALS Laboratories in Nouakchott
under the supervision of Aura's geologist. In 2022, 174 density measurements
were taken on drill core by MMM Laboratories SARL in Nouakchott, under the
supervision of an Aura geologist.
· Database management was undertaken by Reflex Hub in Perth
prior to July 2019, and by Earth SQL in Melbourne after that date.
Sub-sampling techniques and sample preparation
· If core, whether cut or sawn and whether quarter, half or all core
taken.
· If non-core, whether riffled, tube sampled, rotary split, etc and
whether sampled wet or dry.
· For all sample types, the nature, quality and appropriateness of the
sample preparation technique.
· Quality control procedures adopted for all sub-sampling stages to
maximise representivity of samples.
· Measures taken to ensure that the sampling is representative of the
in-situ material collected, including for instance results for field
duplicate/second-half sampling.
· Whether sample sizes are appropriate to the grain size of the
material being sampled.
· 2010/2011/12/15 AC drill samples were riffle split on
site to provide a minimum 2kg sample for assay and a duplicate split for
reference and possible umpire analysis.
· Duplicates, blanks, and standards were inserted in the
assay sample stream at regular intervals as detailed in the next section.
· Drill core from 2017 was cut in half longitudinally by
diamond saw by ALS Laboratories after marking up by, and under the supervision
of, an Aura geologist. This task was completed in 2022 by MMM Laboratories in
Nouakchott, under the supervision of an Aura geologist.
· For each half-metre of core, half-core was bagged for
assay.
· Given the fine-grained nature of the uranium minerals
these sample sizes are appropriate.
Quality of assay data and laboratory tests
· The nature, quality and appropriateness of the assaying and
laboratory procedures used and whether the technique is considered partial or
total.
· For geophysical tools, spectrometers, handheld XRF instruments, etc,
the parameters used in determining the analysis including instrument make and
model, reading times, calibrations factors applied and their derivation, etc.
· Nature of quality control procedures adopted (eg standards, blanks,
duplicates, external laboratory checks) and whether acceptable levels of
accuracy (i.e. lack of bias) and precision have been established.
· 2010/2011/12 AC drill samples were submitted to Stewart
Laboratories sample preparation facility near Zouérat in Mauritania (In 2012
Stewart Laboratories became part of ALS Laboratories). Samples were crushed by
jaw crusher to -12mm and 1kg was riffle split for pulverising to +85% passing
75 microns. An c. 100g split was bagged and sent to Stewart Laboratories in
Ireland for analysis by pressed pellet XRF. Previous analysis comparing
different analytical methods (XRF, ICP, DNC) had indicated that XRF is an
accurate method on this material, if an x-ray band is selected for measurement
that is not affected by the presence of strontium, and this was done. This
method will measure total uranium.
2015 AC drill samples were submitted to ALS Laboratories sample preparation
facility in Nouakchott Mauritania. Samples were crushed by jaw crusher to
-12mm and 1kg was riffle split for pulverising to +85% passing 75 microns. An
c. 100g split was bagged and sent to ALS Global in Ireland for analysis by ALS
method MC-ICP61 after 4-acid digestion. This method will measure near total
uranium.
· For diamond core drilled in 2017, bagged ½ core was
prepared by ALS Laboratories Nouakchott by Method Prep 22 (Crush to 70% less
than 6mm, pulverize entire sample to better than 85% passing 75 microns). An
c. 100g sample of pulp was split off using mini-riffle splitter, placed in
sample envelope and forwarded by air to ALS in Ireland for uranium analysis by
ALS Method U-MS62 (U by ICP-MS after 4 acid digestion). 4 acid digestion
provides near total extraction.
· For diamond core drilled in 2022, sample preparation was
completed by MMM Laboratories in Noakchott. Samples were crushed to 70% less
than 6mm, pulverize entire sample to better than 85% passing 75 microns. An c.
100g sample of pulp was split off using rotary splitter, placed in sample
envelope and forwarded by air to ALS in Ireland for uranium analysis by ALS
Method U-MS62 (U by ICP-MS after 4 acid digestion). ROL-21 agitation was
carried out on the pulps before selecting assay aliquot. 4 acid digestion
provides near total extraction.
· Downhole gamma logging was performed by 2 down-hole
Auslog gamma sondes comprising:
§ DLS5 Winch Controller
§ W600-1 12V Portable Winch
§ A075 Natural Gamma Tool
· Logging procedures involved:
§ Drill holes were gamma logged as soon as possible after drilling to
avoid radon build-up.
§ Each borehole logged in both directions to verify consistency.
§ Logging speed: 2 metres per minute
§ Sampling interval: 1cm
§ At least one hole was re-logged after each 20 holes as a repeatability
check.
§ A reference hole was established and relogged every 2 days as a check
on consistency.
§ Gamma logging procedures & interpretation were supervised by
consultant David Wilson who qualifies as a Competent Person in these matters.
· QAQC procedures for the 2011/12 AC drilling comprised, on
average:
§ Field duplicates assays: 1 in every 12 samples
§ Blanks: 1 in every 31 samples
§ Umpire assays: 1 in every 11 samples
Umpire analysis was carried on 427 sample intervals. For each of these the
original pressed pellet XRF sample assayed by Stewart Labs was re-assayed by
ICP by Stewart Labs. Each of these samples was also assayed by XRF and by ICP
by ALS Labs.
§ Certified Reference material: 1 in every 129 samples
§ Total QAQC samples: 1 in every 5 samples
Accuracy & precision were within acceptable limits.
· QAQC procedures for the 2017 and 2022 diamond drilling
comprise, submission of one standard, blank and field duplicate every 25
samples. In each set of 25 samples, a blank was inserted at every tenth
position, standard at every twentieth position and field duplicate every
25(th) position.
· 190 sample pulps sent to ANSTO Minerals at Lucas Heights
for U determination by Delayed Neutron Count, serving as the Umpire analysis.
· Certified reference standards at 128, 264, and 550ppm
were purchased from African Mineral Standards, South Africa. Blanks were
prepared from sand collected near the University of Nouakchott, that had been
scanned with a hand-held spectrometer.
Verification of sampling and assaying
· The verification of significant intersections by either independent
or alternative company personnel.
· The use of twinned holes.
· Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic) protocols.
· Discuss any adjustment to assay data.
· Excluding the 2009 and 2015 programs, ie for all drilling
included in this MRE, 7945 holes were drilled in total. Of these, 7820 were
aircore, and 125 were PQ diamond core. Approximately 76 % of holes were
surveyed using downhole gamma, while diamond drillholes were both gamma logged
and chemically assayed for validation purposes. The holes drilled in 2009 and
2015 were excluded from all resource estimates and this report (887 holes).
· To test for radioactive disequilibrium 343 samples were
sent to Australian Nuclear Science and Technology Organisation (ANSTO) in
Australia for equilibrium determinations. Results were compiled and
interpreted by D Wilson of 3D Exploration. Disequilibrium factors were
produced in two different ways. The first was based on laboratory measurements
made at ANSTO, which suggested a disequilibrium factor of 1.29. The second was
comparison of drill core assay results against downhole gamma logging which
suggested a conversion factor of 1.16. When the apparent under estimation of
grade by ICP analysis (in comparison to the more accurate DNA analysis) by 7%
is taken into consideration the drill hole assay data imply a conversion
factor of 1.24. Aura personnel decided a disequilibrium factor of 1.25 was
appropriate and applied this to convert eU3O8 grades to U3O8 grades. A factor
of 1.25 needs to be applied to all raw gamma grades to provide the correct U
grade. All drillhole data recorded was uploaded to Aura's online database
managed by Reflex Hub during the programs prior to July 2019 and managed by
Earth SQL after that date. Analyses were forwarded directly from the
laboratories to the database manager for incorporation in the database.
Location of data points
· Accuracy and quality of surveys used to locate drill holes (collar
and down-hole surveys), trenches, mine workings and other locations used in
Mineral Resource estimation.
· Specification of the grid system used.
· Quality and adequacy of topographic control.
· 2010/2011/12 drillhole collars were surveyed by handheld
GPS. According to Garmin, 90% of handheld GPS coordinates should fall within
15m accuracy for modern hand-held GPS units.
· All 2017, 2022, and 2024 drillhole collars were surveyed
by differential surveying conducted by IRC-Magma (ISO 9001-2015) to an
accuracy of +/- 20cm in all dimensions.
· In 2024, Survey was undertaken prior to demobilisation of
the on-site geological staff, and checks were undertaken to ensure all DGPS
surveys fell within 15.2 metres of the hand-held gps. Any questionable holes
were re-surveyed before demobilisation.
· The grid projection used is UTM WGS84 Zone 29N.
· An independent check comparing data gathered prior to
2022 to topography was undertaken by PhotoSat of Vancouver, using satellite
data provided to an accuracy of +/- 20cm, confirming the quality and adequacy
of topographic control.
Data spacing and distribution
· Data spacing for reporting of Exploration Results.
· Whether the data spacing, and distribution is sufficient to establish
the degree of geological and grade continuity appropriate for the Mineral
Resource and Ore Reserve estimation procedure(s) and classifications applied.
· Whether sample compositing has been applied.
· In most cases Measured Resources are based on 50m x 50m
spaced drillholes, Indicated Resources are based on 100m x 100m spaced holes,
and Inferred Resources on 100m x 200m spaced holes.
· Downhole gamma data was composited into 0.5m intervals.
· Three 100m x 100m areas were drilled at 12.5m spacing in
both N-S & E-W directions for geostatistical purposes and to examine
variability. Resource modelling, estimation and classification was done by the
independent resource consultants.
Orientation of data in relation to geological structure
· Whether the orientation of sampling achieves unbiased sampling of
possible structures and the extent to which this is known, considering the
deposit type.
· If the relationship between the drilling orientation and the
orientation of key mineralised structures is considered to have introduced a
sampling bias, this should be assessed and reported if material.
· In 2017, three 100m x 100m squares were drilled at 12.5m
hole spacing in both N-S and E-W directions to investigate grade anisotropy.
This indicated a weak NW-SE trend to the mineralisation. The drilling pattern
employed is considered appropriate for the mineralisation orientation. In
2022, a further two such detailed patterns were drilled.
· The calcrete mineralisation is flat lying to
sub-horizontal so vertical holes were drilled, intersecting the mineralisation
at a high angle.
· The collars are spaced in a grid pattern so provide
adequate coverage of the mineralisation, demonstrating a broad NW-SE linearity
to the mineralisation, with some internal areas running NE-SW.
Sample security
· The measures taken to ensure sample security.
· Sample collection was supervised by geologists. Samples
were transported as soon as practicable to independent sample preparation
facilities.
· The core samples were transported to the processing
facility in Nouakchott where they were logged, and sample selection was
undertaken by geologists. The core trays were then transported to MMM
laboratories in Nouakchott for cutting, sampling and sample preparation. The
pulped samples were sent to ALS Ireland for analysis.
· Approximately 76% of drillholes in the Tiris Project
(East and West) were surveyed by downhole gamma logging and for these, sample
security is not relevant.
Audits or reviews
· The results of any audits or reviews of sampling techniques and data.
· A site inspection was conducted by Oliver Mapeto of
Coffey Mining in 2012. A resource report from 2012 was independently reviewed
and confirmed by Wardell Armstrong International in 2016. A Resource Estimate
at Sadi was done in 2021 by Oliver Mapeto acting then as an independent
consultant. The 2018, 2023 and 2024 Mineral Resource Estimates have been
carried out by independent consulting group H&S Consultants Pty Ltd. All
of these consulting groups have reviewed and endorsed the sampling, grade
estimation and QAQC procedures. Dr Michael Fletcher from GeoEndeavours Pty
Ltd. undertook a field inspection in July 2022. Arnold van der Heyden from
H&S Consultants, undertook a field inspection in January 2024.
Section 2 Reporting of Exploration Results
(Criteria listed in the preceding section also apply to this section)
Criteria JORC Code explanation Commentary
Mineral tenement and land tenure status · Type, reference name/number, location and ownership including · The 2024 drilling was conducted on 1 mineral exploration
agreements or material issues with third parties such as joint ventures, permit held 100% by Aura Energy: 2365B4 Oued EL Foule Sud, and on 2
partnerships, overriding royalties, native title interests, historical sites, Exploitation permits (for which Mining conventions have been signed): 2492C4
wilderness or national park and environmental settings. Oued El Foule, 2491C4 Ain Sder held by Tiris Ressources SA. Tiris Ressources
SA is owned 85% by Aura Energy subsidiary, Aura Energy Mauritania and 15% by
· The security of the tenure held at the time of reporting along with ANARPAM, a Mauritanian Government entity.
any known impediments to obtaining a licence to operate in the area.
· During the current program, a mineral resource estimate
was undertaken on 562B4 Oum Ferkik to bring it in line with the resource
calculation methods in Tiris East. This mineral exploration permit is held
100% by Aura Energy. An application for an Exploitation permit has been
submitted for this Lease.
· Aura has completed an Environmental and Social Impact
Assessment which concluded there are no known issues arising from native
title, historical sites, environmental or third-party matters which are likely
to materially affect exploitation.
Exploration done by other parties · Acknowledgment and appraisal of exploration by other parties. · Aura is unaware of any prior exploration on these areas,
other than governmental data gathering projects such as the PRISM-II
Mauritania Minerals Project (USGS)
Geology · Deposit type, geological setting and style of mineralisation. · The mineralisation is of the surficial uranium style. It
occurs within rocks derived from the Proterozoic Reguibat Craton. The
mineralisation is developed within near surface altered and weathered
granites, and within shallow colluvium lying on granite or adjacent
metasediments.
Drill hole Information · A summary of all information material to the understanding of the · Specific drillhole data is not relevant to the reporting
exploration results including a tabulation of the following information for of this resource estimation because the topography is not significantly
all Material drill holes: variable, and all holes are vertical, drilled almost perpendicular to
sub-horizontal mineralisation at depth of less than 10 metres.
1. easting and northing of the drill hole collar
2. elevation or RL (Reduced Level - elevation above sea level in metres)
of the drill hole collar
3. dip and azimuth of the hole
4. down hole length and interception depth
5. hole length.
· If the exclusion of this information is justified on the basis that
the information is not Material and this exclusion does not detract from the
understanding of the report, the Competent Person should clearly explain why
this is the case.
Data aggregation methods · In reporting Exploration Results, weighting averaging techniques, · Data aggregation methods are summarised in the Resource Estimate
maximum and/or minimum grade truncations (eg cutting of high grades) and report by H&S Consultants which this table accompanies.
cut-off grades are usually Material and should be stated.
· Where aggregate intercepts incorporate short lengths of high-grade
results and longer lengths of low grade results, the procedure used for such
aggregation should be stated and some typical examples of such aggregations
should be shown in detail.
· The assumptions used for any reporting of metal equivalent values
should be clearly stated.
Relationship between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of · All drillholes on which the resource estimate is based
Exploration Results. were vertical and approximately perpendicular to the thickness of the sub
horizontal mineralisation.
· If the geometry of the mineralisation with respect to the drill hole
angle is known, its nature should be reported.
· If it is not known and only the down hole lengths are reported, there
should be a clear statement to this effect (eg 'down hole length, true width
not known').
Diagrams · Appropriate maps and sections (with scales) and tabulations of · Refer to the ASX announcement which this table
intercepts should be included for any significant discovery being reported accompanies.
These should include, but not be limited to a plan view of drill hole collar
locations and appropriate sectional views.
Balanced reporting · Where comprehensive reporting of all Exploration Results is not ·
practicable, representative reporting of both low and high grades and/or
widths should be practiced to avoid misleading reporting of Exploration
Results.
Other substantive exploration data · Other exploration data, if meaningful and material, should be · Metallurgical testwork is ongoing. Information on
reported including (but not limited to): geological observations; geophysical processing has been reported in;
survey results; geochemical survey results; bulk samples - size and method of
treatment; metallurgical test results; bulk density, groundwater, geotechnical · ASX release: 29 July 2019 - Tiris Uranium Definitive
and rock characteristics; potential deleterious or contaminating substances. Feasibility Study Completed
· ASX release 23 June 2022 - confirms average 550%
upgrading of uranium with simple screening in test-work
· ASX release: 29 March 2023 - Tiris Uranium Project
Enhanced Definitive Feasibility Study
· ASX release: 28 Feb 2024 - FEED study confirms excellent
economics for the Tiris Uranium Project
· Metallurgical testwork pits were undertaken in the 2024
field program and the data is currently being processed.
Further work · The nature and scale of planned further work (eg tests for lateral · An assessment of further mineral potential and drilling
extensions or depth extensions or large-scale step-out drilling). opportunities on these Leases is currently being undertaken.
· Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling areas,
provided this information is not commercially sensitive.
Section 3. Estimation and Reporting of Mineral Resources
Criteria JORC Code explanation Commentary
Database integrity · Measures taken to ensure that data has not been corrupted by, for The Aura resource database is managed by independent organisation Reflex Hub,
example, transcription or keying errors, between its initial collection and based in Perth.
its use for Mineral Resource estimation purposes.
HSC conducted some basic checks for internal inconsistencies such as
· Data validation procedures used. overlapping intervals, records beyond end of hole depth, unassayed intervals
and unrealistic data values.
Twinned drill holes, generally within 10m, were identified and examined. Twins
without assays or shallower holes were removed for geological interpretation
and grade estimation.
Site visits · Comment on any site visits undertaken by the Competent Person and the The Competent Person for the Mineral Resource Estimate (MRE) undertook a site
outcome of those visits. visit to the Tiris East project area in January 2024. Two days were spent on
site observing air-core drilling operations including down-hole gamma logging,
· If no site visits have been undertaken indicate why this is the case. as well as inspecting the geology of each of the major deposits and locating
older drill hole collar locations. A further half day was spent in the capital
Nouakchott inspecting core and sample storage at the AEE storage facility.
The drilling and gamma logging were being performed in a professional manner
and the core inspection confirmed the presence of significant uranium
mineralisation.
Geological interpretation · Confidence in (or conversely, the uncertainty of) the geological The uranium mineralisation generally forms thin shallow horizontal tabular
interpretation of the mineral deposit. bodies ranging in thickness from 1 to 12m hosted in weathered granite and
granitic sediments. Differentiation of the weathered granite from granitic
· Nature of the data used and of any assumptions made. sediments is unreliable from air-core sample returns.
· The effect, if any, of alternative interpretations on Mineral Resource HSC generated surfaces representing the base of the mineralisation at each
estimation. deposit in order to limit the extrapolation of grades into volumes that have
no data. This is important at Tiris as there is a general decrease in uranium
· The use of geology in guiding and controlling Mineral Resource grades with depth.
estimation.
These basal surfaces generally represent the top of fresh granite, where
· The factors affecting continuity both of grade and geology. air-core drilling could penetrate no further. The basal surfaces were produced
using the locations of the end of the deepest assay from each drill hole.
The exceptions are the 2022 air-core drilling, when a hydraulic hammer was
used instead of a conventional blade bit, and all diamond core holes.
Therefore, these holes could penetrate fresh rock, while the blade bit used in
other years could not. This difference is important to the Tiris project
because the DFS assumes that mining will be free-digging. Consequently, fresh
rock intersected in the 2022 air-core holes and all diamond core drilling will
not be mineable under current assumptions and needs to be excluded from the
MRE. Therefore, in deposits with 2022 air-core holes and diamond core drilling
(Sadi, Lazare South and Hippolyte North), an additional surface was created to
represent the top of fresh rock, which may be shallower than the base of
mineralisation in places.
Areas of obvious outcrop were excised from the MRE assuming a dip of 45
degrees between weathered granite/granitic sediments and the fresh granite.
At the time that the estimates were completed, no topographic survey data were
available. The majority of the recent drill collar locations were surveyed
using a Differential Global Positioning System (DGPS). HSC used the locations
of all drill hole collars that had been located with the DGPS to create a
wireframe representing the topographic surface. The elevations of all drill
holes that had been located using a handheld GPS were then derived from this
topographic surface.
All geological models contain block proportions of material:
· Below topography
· Above base of mineralisation
· Above top of fresh rock
· Above top of holes
These proportions were later combined to assess estimates of material between
the different surfaces.
The block proportion below topography was used to assign average block depth,
which was used to calculate dry bulk density and allow assessment of
mineralisation in one metre slices below surface.
The interpretation of the mineralisation as flat lying tabular bodies is
undisputed. The lateral extents of the mineralisation are poorly defined and
recent drilling around the edges of the deposits shows that mineralisation is
not necessarily limited to areas with stronger surface radiometric anomalies.
The extent of outcrop/subcrop and its relationship to free-digging
mineralisation is somewhat uncertain but a conservative approach has been
taken to minimise this risk.
Alternative interpretations of the geology are unlikely to significantly
impact estimated resources.
The continuity of both grade and geology are affected by the extent of
weathering of the granitic host. Continuity does not appear to be affected by
faulting.
The models account for sand dunes that overlie mineralisation in places that
can be over 10m high. These dunes move on an annual basis within specific
corridors. AEE provided the outlines of the base of sand dunes from aerial
imagery and HSC generated volumes based on a nominal height of 10m. The
modelling of these volumes and their location is somewhat subjective, but it
does give a nominal indication of the location of the sand dune corridors.
Dimensions · The extent and variability of the Mineral Resource expressed as length The MREs reported here occur in ten separate deposits in two areas (Tiris East
(along strike or otherwise), plan width, and depth below surface to the upper and Tiris West) separated by ~200km. All MREs are reported at 100ppm U(3)O(8)
and lower limits of the Mineral Resource. cut-off grade.
The Tiris East area comprises 8 separate deposits within a rectangle around
35km north-south and 74km east-west.
1. The Sadi MRE occurs in an irregular NNW trending area with a
north-south length of 10.6km and an average east-west extent of ~3.0km. There
are a few smaller patches of mineralisation outside the main zone. The MRE
starts at surface and extends to a maximum depth of 17m below surface,
although the majority of mineralisation occurs within 8m of surface.
2. The Lazare North MRE occurs over an area of 4.8km east-west and
averages ~2.0km north-south. It comprises two main areas with an additional
small patch in the north-west. The MRE starts at surface and extends to a
maximum depth of 12m below surface, although the majority of mineralisation
occurs within 7m of surface.
3. The Lazare South MRE occurs over an area of 7.8km east-west and
averages ~1.5km north-south. It comprises two main areas with an additional
smaller patch to the east. The MRE starts at surface and extends to a maximum
depth of 19m below surface, although the majority of mineralisation occurs
within 6m of surface.
4. The Hippolyte North MRE occurs as multiple lenses over an area of
6.1km east-west and 9.6km north-south, and was divided into 7 separate zones
for grade estimation. The MRE starts at surface and extends to a maximum depth
of 11m below surface, although the majority of mineralisation occurs within 6m
of surface.
5. The Hippolyte South MRE occurs as multiple lenses over an area of
8.0km east-west and 9.2km north-south, and was divided into 5 separate zones
for grade estimation. The MRE starts at surface and extends to a maximum depth
of 9m below surface, although the majority of mineralisation occurs within 6m
of surface.
6. The Hippolyte East MRE occurs as four separate lenses over an area
of 3.8km east-west and 4.3km north-south, and was divided into 3 separate
zones for grade estimation. The MRE starts at surface and extends to a maximum
depth of 8m below surface, although the majority of mineralisation occurs
within 5m of surface.
7. The Hippolyte West C MRE occurs as a single irregular zone over an
area of 3.6km north-south and averages ~1.3km east-west. The MRE starts at
surface and extends to a maximum depth of 10 m below surface, although the
majority of mineralisation occurs within 7m of surface.
8. The Marie MRE occurs as four separate zones over an area of ~12km
east-west and ~7.5km north-south. Marie E extends 1.8 km N-S and 0.6km E-W;
Marie F is 1.8km N-S and 0.75km E-W; Marie G is 1.5km N-S and 2.0km E-W; and
Marie H is 4.0km N-S and 0.6km E-W. The MRE starts at surface and extends to a
maximum depth of 9m below surface, although the majority of mineralisation
occurs within 6m of surface.
The Tiris West area comprises 2 separate deposits within a rectangle around
3.4km north-south and 7.2km east-west.
9. The Oum Ferkik K MRE occurs as a single irregular zone over an area
with maximum dimensions of 2.6km north-south and 2.4km east-west. The MRE
starts at surface and extends to a maximum depth of 11m below surface,
although the majority of mineralisation occurs within 6m of surface.
10. The Oum Ferkik L MRE occurs as a single irregular zone over an area
with maximum dimensions of 2.9km north-south and 1.9km east-west. The MRE
starts at surface and extends to a maximum depth of 11m below surface,
although the majority of mineralisation occurs within 6m of surface.
These dimensions do not account for sand dunes that overly parts of some
deposits because the dunes move on an annual basis and the modelling of their
volumes and location is somewhat subjective.
Estimation and modelling techniques · The nature and appropriateness of the estimation technique(s) applied New estimates were generated for all deposits reported here. There is
and key assumptions, including treatment of extreme grade values, domaining, additional recent drilling for all the Tiris East deposits, while Tiris West
interpolation parameters, maximum distance of extrapolation from data points. was re-estimated with existing historical data using the same methodology as
Tiris East to make all estimates consistent and compatible.
· The availability of check estimates, previous estimates and/or mine
production records and whether the Mineral Resource estimate takes appropriate Uranium concentration was estimated by recoverable Multiple Indicator Kriging
account of such data. (MIK) using GS3 geostatistical software. The uranium grades at the Tiris
deposits exhibit a positively skewed distributions and therefore show
· The assumptions made regarding recovery of by-products. reasonable sensitivity to a small number of high grades. MIK is considered an
appropriate estimation method for the uranium grade distribution at the Tiris
· Estimation of deleterious elements or other non-grade variables of deposits because it specifically accounts for the changing spatial continuity
economic significance (e.g. sulphur for acid mine drainage characterisation). at different grades through a set of indicators variograms at a range of grade
thresholds. It also reduces the need to use the practice of top cutting.
· In the case of block model interpolation, the block size in relation to
the average sample spacing and the search employed. All drill hole intervals were composited to 0.5m for estimation.
· Any assumptions behind modelling of selective mining units. No direct top-cuts were applied but the average of the mean and median grades
was applied to the top indicator class to address any potential extreme
· Any assumptions about correlation between variables. values.
· Description of how the geological interpretation was used to control The larger deposits were subdivided into a number of Subzones for estimation,
the resource estimates. with conditional statistics generated for each of the subzones. All class
grades used for estimation of the mineralised domains were derived from the
· Discussion of basis for using or not using grade cutting or capping. class mean grades, except the top indicator class.
· The process of validation, the checking process used, the comparison of Only U(3)O(8) was estimated. No deleterious elements or other non-grade
model data to drill hole data, and use of reconciliation data if available. variables of economic significance were estimated.
Vanadium is a potential by-product and vanadium oxide (V2O5) has been
estimated for the mineral resources using the stoichiometric V(2)O(5)/
U(3)O(8) ratio for carnotite group minerals. These V(2)O(5) values represent
potentially recoverable vanadium in carnotite and not total vanadium occurring
in mineralisation, which is significantly higher in almost all cases. These
potentially recoverable V(2)O(5) values are based on the analysis of a
substantial database of available sample data and represent average values
that may be conservative. This procedure relies on the correlation between
uranium and vanadium in carnotite group minerals, which are the only uranium-
vanadium minerals identified to date at Tiris. The base of mineralisation
surface was used to limit the extrapolation of grades into volumes that had no
data.
The proportion of outcrop was estimated for each block based on digitising
provided by AEE and used to deplete the MRE on the assumption that this
material cannot be dug freely.
The Recoverable MIK technique employed by HSC in this case requires a set of
14 variogram models, one for each of the fourteen grade bins used. Sets of
variogram models were created for the major Subzones and were applied to
Subzones that did not have sufficient data to generate reliable models.
Drill hole spacing varies from 50x50m or 70x70m in the better drilled
deposits, out to 100x200m in the less well drilled deposits.
Sample length varies by assay type and year. Earlier chemical assays
(2009-2012) are typically 1.0m in length, apart from 0.5m intervals for the
first metre in each holes. Later (2017-2022) chemical assays are consistently
0.5m in length. All raw radiometric data (one centimetre readings) has been
composited to regular 0.5m intervals. All drill hole grade data were
composited to nominal 0.5m intervals for analysis and estimation.
The block dimensions were 50x50m in plan view and 1 m vertically. The plan
dimensions were chosen as it is the nominal drill hole spacing (preferable for
MIK estimation). The vertical dimension was chosen to reflect the anisotropy
of the mineralisation and the downhole data spacing.
The minimum selective mining unit size is assumed to be 10x10x0.5m.
A three-pass search strategy was used to estimate the U(3)O(8) grades at each
of the deposits. Each pass required a minimum number of samples with data from
a minimum number of octants of the search ellipse to be populated.
Discretisation was set to 5x5x2 points in X, Y and Z, respectively. The
search criteria are shown below. The last short axis of the search ellipse is
vertical.
1. 80x80x2.0m search, 16-48 samples, minimum 4 octants
2. 160x160x2.0m search, 16-48 samples, minimum 4 octants
3. 240x240x3.0m search, 8-48 samples, minimum 2 octants
The maximum distance of extrapolation of the reported estimates from drill
hole data points is limited to around 220m.
The estimates were reviewed by HSC personnel, and it was concluded that the
estimates reasonably represent the grades observed in the drill holes. HSC
also validated the models statistically using histograms, boxplots, scatter
plots and summary statistics.
No independent check estimates were produced but the new models were compared
to previous estimates and found to be consistent and compatible. The new MRE
takes appropriate account of previous estimates.
No mining has occurred on the Tiris deposits so mine production data were
unavailable for comparison.
Moisture · Whether the tonnages are estimated on a dry basis or with natural Tonnages are estimated on a dry weight basis. The moisture constant was not
moisture, and the method of determination of the moisture content. determined.
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters A cut-off grade of 100ppm U(3)O(8) is used to report the resources as it is
applied. assumed that ore can be economically mined at this grade in an open pit
scenario. This cut-off is considered to be relatively low compared to
operating uranium mines, but metallurgical test work indicates that a
significant upgrade in uranium and decrease in sulphates can be achieved by a
simple screening process.
Mining factors or assumptions · Assumptions made regarding possible mining methods, minimum mining All of the resources reported here have been estimated on the assumption that
dimensions and internal (or, if applicable, external) mining dilution. It may the deposits will be mined by open-pit and free digging, with no blasting or
not always be possible to make assumptions regarding mining methods and crushing.
parameters when estimating Mineral Resources. Where no assumptions have been
made, this should be reported. Recoverable MIK allows for block support correction to account for the change
from sample size support to the size of a mining block. This process requires
an assumed grade control drill spacing and the assumed size of the Selective
Mining Unit (SMU). The variance adjustment factors were estimated from the
U(3)O(8) metal variogram models assuming a minimum SMU of 10x10x0.5m (east,
north, vertical) with high quality grade control sampling on a 10x10x0.5m
pattern (east, north, vertical).
Internal dilution within the SMUs is accounted for by the estimation method;
external mining dilution and other mining recovery factors are not included in
the estimates.
If a larger SMU size or a broader grade control drill pattern is implemented,
then the selectivity assumed in the reported resources may not be realised.
Metallurgical factors or assumptions · The basis for assumptions or predictions regarding metallurgical The metallurgical test work information supplied to HSC indicates that the
amenability. It may not always be possible to make assumptions regarding Tiris deposits are amenable to a process of crushing, screening and an
metallurgical treatment processes and parameters when reporting Mineral alkaline carbonate leach in order to recover uranium. Bench scale test work
Resources. Where no assumptions have been made, this should be reported. indicates that a significant upgrade in uranium and decrease in sulphate
concentrations can be achieved through screening.
No penalty elements identified in work so far.
No other assumptions have been made.
Environmental factors or assumptions · Assumptions made regarding possible waste and process residue disposal AEE has informed HSC that an Environmental and Social Impact Assessment has
options. It is always necessary as part of the process of determining been completed, which concluded there are no known issues arising from native
reasonable prospects for eventual economic extraction to consider the title, historical sites, environmental or third-party matters which are likely
potential environmental impacts of the mining and processing operation. While to materially affect exploitation. HSC therefore assumes that there are no
at this stage the determination of potential environmental impacts, known unusual aspects of the Tiris deposits that may lead to adverse
particularly for a greenfields project, may not always be well advanced, the environmental impacts beyond what is expected from a mining operation.
status of early consideration of these potential environmental impacts should
be reported. Where these aspects have not been considered this should be
reported with an explanation of the environmental assumptions made.
Waste rock and process residue is expected to be disposed of in the areas
surrounding the deposits and processing facility in a responsible manner and
in accordance with all mining lease conditions.
Bulk density · Whether assumed or determined. If assumed, the basis for the Dry bulk density of diamond drill core samples was measured at the ALS
assumptions. If determined, the method used, whether wet or dry, the frequency facility in Nouakchott using an immersion method (Archimedes principle) on
of the measurements, the nature, size and representativeness of the samples. selected PQ diamond drill core intervals ranging in size from 10 to 30cm.
Competent pieces of drill core were selected on a nominal interval of 50cm.
The samples chosen are believed to be representative of the surrounding rock
type. All density samples are wrapped in cling film to avoid water absorption.
A total of 412 density measurements have been taken from drill core at the
Tiris deposits with values ranging from 1.50 to 2.66t/m3 and averaging 2.13
t/m3.
Measured density values show that there is a reasonable correlation between
density and the depth of the sample. A regression was used to assign densities
to each block in the block models based on depth below surface.
Classification · The basis for the classification of the Mineral Resources into varying The classification is based on the search pass used to estimate the block.
confidence categories.
In some cases, the blocks at surface were populated in a later search pass
· Whether appropriate account has been taken of all relevant factors than blocks immediately below, as these blocks did not meet the minimum search
(i.e., relative confidence in tonnage/grade estimations, confidence in criteria due to the fact that there are no samples above the topography. In
continuity of geology and metal values, quality, quantity and distribution of order to alleviate this, the minimum search pass from a column of blocks was
the data). propagated upwards.
· Whether the result appropriately reflects the Competent Person's view Pass one nominally equates to Measured Resources, pass two translates to
of the deposit. Indicated Resources and Pass three equates to Inferred Resources.
In deposits drilled entirely at 100x200m hole spacing, the entire resource was
classified as Inferred, regardless of estimation pass, to maintain consistency
with previous estimates.
A small number of estimated model blocks occur outside the current AEE leases,
and these were excluded from the reported MRE.
This scheme is considered by HSC to take appropriate account of all relevant
factors, including the relative confidence in tonnage and grade estimates,
confidence in the continuity of geology and metal values, and the quality,
quantity and distribution of the data.
The classification appropriately reflects the Competent Person's view of the
deposit.
Audits or reviews · The results of any audits or reviews of Mineral Resource estimates. This Mineral Resource estimate has been reviewed by Aura personnel. The
estimation procedure has also been internally reviewed by HSC. No material
issues were identified as a result of these reviews.
No independent external audits have been completed on the Mineral Resource
estimates.
Discussion of relative accuracy/ confidence · Where appropriate a statement of the relative accuracy and confidence The relative accuracy and confidence level in the Mineral Resource estimates
level in the Mineral Resource estimate using an approach or procedure deemed are considered to be in line with the generally accepted accuracy and
appropriate by the Competent Person. For example, the application of confidence of the nominated JORC Mineral Resource categories. This has been
statistical or geostatistical procedures to quantify the relative accuracy of determined on a qualitative, rather than quantitative, basis, and is based on
the resource within stated confidence limits, or, if such an approach is not the estimator's experience with a number of deposits at NPM and similar
deemed appropriate, a qualitative discussion of the factors that could affect deposits elsewhere. The main factors that affect the relative accuracy and
the relative accuracy and confidence of the estimate. confidence of the estimate are the drill hole spacing and the style of
mineralisation.
· The statement should specify whether it relates to global or local
estimates, and, if local, state the relevant tonnages, which should be The estimates are local, in the sense that they are localised to model blocks
relevant to technical and economic evaluation. Documentation should include of a size considered appropriate for local grade estimation. The tonnages
assumptions made and the procedures used. relevant to technical and economic analysis are those classified as Measured
and Indicated Mineral Resources.
· These statements of relative accuracy and confidence of the estimate
should be compared with production data, where available. This deposit remains unmined so there are no production records for
comparison.
1 (#_ftnref1) ASX and AIM Release: 14 Feb 2023 - Major Resource Upgrade at
Aura Energy's Tiris Project
2 (#_ftnref2) ASX and AIM Release: 28 Feb 2024 - FEED study confirms
excellent economics for the Tiris Uranium Project
3 (#_ftnref3) ASX and AIM Release: 28 Feb 2024 - FEED study confirms
excellent economics for the Tiris Uranium Project
4 (#_ftnref4) ASX and AIM Release: 16 April 2024 - Offtake restructure
delivers significant value
5 (#_ftnref5) ASX and AIM Release: 14 Feb 2023 - Major Resource Upgrade at
Aura Energy's Tiris Project
6 (#_ftnref6) ASX and AIM Release: 29 April 2024 - Tiris extensional drill
programme completed
7 (#_ftnref7) ASX and AIM Release: 17 Oct 2023 - New Uranium Exploration
Target identified at Tiris Project
8 (#_ftnref8) ASX and AIM Release: 29 Nov 2023 - New Tiris Project Tenements
Applications
9 (#_ftnref9) ASX and AIM Release: 28 Feb 2024 - Aura's Tiris FEED Study
Returns Excellent Economics and ASX Release: 16 April 2024 - Offtake
restructure delivers significant value
10 (#_ftnref10) ASX Release: 28 Feb 2024 - FEED study confirms excellent
economics for the Tiris Uranium Project
11 (#_ftnref11) ASX Announcement 29th March 2023; Enhanced Definitive
Feasibility Study confirms robust financial returns and near-term production
potential of the Tiris Uranium Project.
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