Metallurgical tests show pathway to reduced processing costs
Released
Released
Announcement PDF
Koppamurra Rare Earths Project, South Australia
May 16, 2023
Highly successful metallurgical tests point
to significantly lower processing costs
Breakthrough testwork shows that removing larger ore particles before processing
increases head grade significantly for little reduction in total recovered rare earths
Australian Rare Earths Limited (ASX: AR3) is pleased to announce pivotal metallurgical test results which
highlight the potential to significantly reduce capital and production costs at its Koppamurra rare earths
project.
The tests demonstrated that the vast majority of the valuable rare earths occur in the smaller particles. By
separating the ore through simple beneficiation, the larger particles could be removed from the downstream
process.
This resulted in 90 per cent of the magnet rare earths being contained in 64 percent of the ore.
The results are considered transformational as they demonstrate the potential to reduce re-agent
consumption, simplify materials handling, reduce the volume of the leach vessels and therefore reduce
capital and operating costs significantly.
Acting Managing Director Rick Pobjoy welcomed the results:
“These latest tests by industry experts ANSTO demonstrate that more than 90 per cent of the important
magnetic rare earths can be captured in less than two thirds of the mass during primary processing when
the maximum feed size is restricted to less than 75 microns.
“This means we could substantially reduce the amount of ore we process substantially, while still maintaining
90 per cent of the valuable rare earths. The potential impact on processing costs and therefore the overall
economics of the project and shareholder returns are extremely substantial.
“Further work is underway on this approach in parallel with our drive to continue growing the Koppamurra
Resource”.
Assay by size – Testwork Outline
ANSTO Minerals (ANSTO) has completed a number of work programs for Australian Rare Earths (AR3) relating
to the recovery of rare earths from the Koppamurra deposit. This latest testwork explores the potential for
screening the mineralised clay to remove a portion of the overall material while retaining the majority of the
REEs and increasing the REE grade.
A scope of work to screen a representative composite sample of the Koppamurra mineral resource and leach
the oversize and undersize fractions was prepared by ANSTO. Initial screening work was conducted at 38 µm,
with diagnostic leach tests conducted on the oversize and undersize fractions. The oversize fraction was
screened further at 45, 75 and 106 µm. Assessment of the screened fractions led to further screening and
leaching of a <75 µm fraction.
Figure 1 - A composite of five composite samples (CP003, CP004, CP006, CP009 & CP010) representative of
the current Koppamurra Mineral Resource were used in this testwork.
The initial screen at 38 µm upgraded the total rare earth + Y oxide (TREYO) in the <38 µm fraction by 37%,
with only 60% of the mass. The TREYO grade improved from 1133 ppm in the head to 1557 ppm. Further
screening of the >38 µm fraction showed 43% of the remaining REs were present in the <75 µm fractions,
with only 14% of the mass. Following assessment of these results, an additional screening test was conducted
at 75 µm. The Magnet REE upgrade to the <75 µm fraction was 41%.
Diagnostic leaches were performed on the size fractions generated through this testwork. The leaches were
used to identify any bias of rare earth recovery toward one size fraction or other. Diagnostic leaches are
conducted at pH 4 and pH 1 and at low solids volumes, establishing baseline rare-earth extraction
characteristics of the samples.
Follow up testing from these test results will include repeating the screening at 75 µm across a number of
other samples and to test leaching at full slurry density (25 wt%), including optimisation of leach pH as
reported previously (ASX: 19/09/2022). This is required to validate the diagnostic results presented here
and gather more information on the resulting acid consumption, leach liquor composition and slurry
handling at the finer particle size.
Further testwork will also include an investigation of the impact of the addition of MgSO4 to the test lixiviant
at various points from pH 1 to pH 4. The results here indicate a positive impact on RE recovery.
Conditions
Sample ID
Reagent
pH
Time (h)
ARE <38 µm
ARE <38 µm
ARE >38 µm
ARE >38 µm
ARE <75 µm
ARE <75 µm
ARE <75 µm
0.3 M MgSO4 (pH 4)
H2SO4 (pH 1)
0.3 M MgSO4 (pH 4)
H2SO4 (pH 1)
0.3 M MgSO4
0.3 M MgSO4
H2SO4 (pH 1)
4.0
1.0
4.0
1.0
4.0
1.0
1.0
0.5
2.0
0.5
2.0
0.5
2.0
2.0
Pr
%
13
42
26
57
18
59
50
Nd
%
14
45
26
57
20
62
52
Tb
%
15
39
24
50
20
52
45
Dy
%
14
33
16
37
19
53
45
LRE
%
7
27
14
68
11
39
38
HRE Magnet REE TREY TREY-Ce
%
%
%
%
15
14
10
15
35
43
29
39
17
25
15
22
39
54
58
45
20
20
14
20
54
60
42
55
45
50
39
46
Table 1 - Magnet Rare Earth recovery (%) at various size fractions and test conditions
The announcement has been authorised for release the by the Board of AR3 Limited.
For further information please contact:
AR3 Limited
Rick Pobjoy
Acting Managing Director
T: 1 300 646 100
Media Enquiries
Nicholas Read / Paul Armstrong
Read Corporate
T: 08 9388 1474
Competent Person’s Statement
The information in this report that relates to metallurgical results is based on information compiled by
Australian Rare Earths Limited and reviewed by Mr. Jon Weir who is the Technical Director – Metallurgy of
Wallbridge Gilbert Aztec and a Member of the Australian Institute of Mining and Metallurgy (M AusIMM).
Mr. Weir has sufficient experience that is relevant to the metallurgical testing which was undertaken 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. Weir consents to the inclusion in this report
of the matters based on this information in the form and context in which it appears.
Listing Rule 5.23 disclosure
The Company confirms that it is not aware of any new information or data that materially affects the
Exploration Results and/or the estimates of Mineral Resources in this release, and in respect of the estimates
of Mineral Resources reported, that all material assumptions and technical parameters underpinning the
estimates continue to apply and have not changed.
About Australian Rare Earths Limited
Australian Rare Earths is committed to the timely exploration and development of its 100% owned, flagship
Koppamurra Project, located in South Australia and Victoria. Koppamurra is a prospective ionic clay hosted
rare earth deposit, uniquely rich in all the elements required in the manufacture of rare earth permanent
magnets which are essential components in electric vehicles, wind turbines and domestic appliances.
The Company is focused on executing a growth strategy that will ensure AR3 is positioned to become an
independent and sustainable source of rare earths, playing a pivotal role in the global transition to a green
economy.
Appendix I
JORC Table 1 – Section 2, Reporting of Exploration Results
Criteria
Mineral
tenement
and land
tenure
status
Section 2 Reporting of Exploration Results
Explanation
Comment
Type, reference
Koppamurra Project comprises of a granted
name/number, location
South Australian Exploration Licences (EL),
and ownership including
EL6509, EL6613, EL6690 and EL6691, along
agreements or material
with Victorian EL007254 covering a combined
issues with third parties
area of ~4,000 km2 which is in good standing.
such as joint ventures,
EL6509 is within 100m of a Glen Roy
partnerships, overriding
Conservation Park and the Naracoorte Caves
royalties, native title
National Park, the latter of which is excised
interests, historical sites,
from the tenement. The License area
wilderness or national
contains several small Extractive Mineral
park and environmental
Leases (EML) held by others, Native
settings.
Vegetation Heritage Agreement areas, as well
The security of the tenure
as the Deadman’s Swamp Wetlands which
held at the time of
are wetlands of national importance.
reporting along with any
known impediments to
A Native Title Claim by the First Nations of the
obtaining a licence to
South East #1 has been registered but is yet
operate in the area.
to be determined. The claim area includes the
areas covered by EL’s 6509, 6613, 6690 and
6691.
The exploration work was completed on the
tenements (EL 6509 and EL6613) in South
Australia and EL007254 which are 100%
owned by the company Australian Rare
Earths Ltd.
The Exploration License EL6509 original date
of grant was 15/09/2020 with an expiry date
of 14/09/2022.
The Exploration License EL6613 original date
of grant was 07/07/2021 with an expiry date
of 06/07/2027.
The Exploration License EL007254 original
date of grant was 29/04/2021 with an expiry
date of 28/04/2024.
Details regarding royalties are discussed in
chapter 3.4 of Australian Rare Earths
Prospectus dated 7 May 2021.
Exploration
done by
other
parties
Acknowledgment and
appraisal of exploration
by other parties.
Exploration activities by other exploration
companies in the area have not previously
targeted or identified REE mineralisation.
Historical exploration activities in the vicinity
of Koppamurra include investigations for coal,
gold and base metals, uranium, and heavy
mineral sands.
Historical exploration by other parties is
detailed in Chapter 7 of Australian Rare
Earths Prospectus dated 7 May 2021.
Geology
Deposit type, geological
setting and style of
mineralisation.
The ionic clay hosted REE mineralisation at
Koppamurra is hosted by clayey sediments
interpreted to have been deposited onto a
limestone base (Gambier Limestone) and
accumulated in an interdunal, lagoonal or
estuarine environment which has been
extensively mapped east of the Kanawinka
fault in SE SA. A dedicated post-doctoral
research program investigating the source of
the REE at Koppamurra is ongoing, with no
definitive source of the REE confirmed to date
although preliminary results of this study
have ruled out the alkali volcanics in southeastern Australia which was originally
considered. Mineralogical test work
conducted on clay samples from the project
area established that the dominant clay
minerals are smectite and kaolin, and that the
few REE-rich minerals detected during the
scanning electron microscope (SEM)
investigation were not considered
inconsistent with the suggestion that a
significant proportion of REE are distributed
in the material as adsorbed elements on clay
and iron oxide surfaces.
Drill hole
Information
A summary of all
information material to
the understanding of the
exploration results
including a tabulation of
the following information
for all Material drill
holes:
- easting and
northing of the drill
hole collar
- elevation or RL
(Reduced Level –
elevation above sea
level in metres) of
the drill hole collar
- dip and azimuth of
the hole
- down hole length
and interception
depth
- 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.
The material information for drill holes
relating to this report are contained within
Appendices of this release.
Data
aggregation
methods
In reporting Exploration
Results, weighting
averaging techniques,
maximum and/or
minimum grade
truncations (eg cutting
of high grades) and cutoff 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.
No metal equivalents or data aggregation
methods have been used.
Relationship
between
mineralisation
widths and
intercept lengths
Diagrams
Balanced
reporting
The assumptions used for
any reporting of metal
equivalent values should
be clearly stated.
These relationships are
particularly important in
the reporting of
Exploration Results.
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’).
Appropriate maps and
sections (with scales)
and tabulations of
intercepts should be
included for any
significant discovery
being reported These
should include, but not
be limited to a plan
view of drill hole collar
locations and
appropriate
sectional views.
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.
All intercepts reported are down hole lengths.
The mineralisation is interpreted to be flat
lying. Morphology of the mineralised unit is
influenced by the morphology of the
undulating limestone basement below.
Drilling is vertical perpendicular to
mineralisation. Any internal variations to REE
distribution within the horizontal layering was
not defined, therefore the true width is
considered not known.
Diagrams are included in the body of this
release.
This release contains all drilling results that
are consistent with the JORC guidelines.
Where data may have been excluded, it is
considered not material.
Other
substantive
exploration data
Further
work
Other exploration data,
if
meaningful
and
material, should be
reported
including (but not
limited to): geological
observations;
geophysical survey
results; geochemical
survey results; bulk
samples – size and
method of treatment;
metallurgical test
results; bulk density,
groundwater,
geotechnical and rock
characteristics;
potential deleterious or
contaminating
substances.
The nature and scale of
planned further work
(eg tests for lateral
extensions or depth
extensions or largescale step-out drilling).
Diagrams clearly
highlighting the areas of
possible extensions,
including the main
geological
interpretations and
future drilling areas,
provided this
information is not
commercially sensitive.
All known relevant exploration data has been
reported in this release.
AR3 intend to continue to define the
Koppamurra resource during 2023. This will
include (but not limited to) drilling, assay,
ground based geophysical surveys and further
metallurgical testwork.
Appendix II
Aircore Drillhole Collars contributing to material provided for
metallurgical test work
Hole_ID East
North
RL
493793 5885320
KM1198
KM1199
493895 5885317
KM1200
493995 5885317
KM1202
493891 5885218
KM1204
493797 5885117
KM1205
493894 5885116
KM1209
493799 5885019
KM1418
495827 5883287
KM1419
495736 5883291
KM1423
495350 5883395
KM1427
495746 5883397
KM1430
495747 5883493
KM1445
495756 5883600
KM1446
495864 5883592
KM1591
495443 5884516
KM1594
495143 5884513
KM1595
495046 5884515
KM1597
495250 5884415
KM1598
495347 5884421
KM1600
495447 5884320
KM1601
495349 5884320
KM1602
495265 5884317
KM1608
496253 5882694
KM1609
496351 5882689
KM1610
496376 5882796
KM1611
496245 5882792
KM1622
496284 5882591
KM1623
496375 5882593
KM1672
494380 5882815
KM1674
494378 5883015
KM1690
494080 5883007
KM1691
494280 5883112
KM1693
494181 5883019
KM1694
494281 5882916
KM1695
494178 5882914
KM1696
494081 5882916
Drill MethoDown Hole Width (mm) Total Depth EOH (m) Azim
96.7 Air-Core
76
8
97.3 Air-Core
76
12
94.9 Air-Core
76
18
98.2 Air-Core
76
9
98 Air-Core
76
6
98.1 Air-Core
76
9
97.8 Air-Core
76
6
110.4 Air-Core
76
6
109.5 Air-Core
76
6
104.3 Air-Core
76
6
107.3 Air-Core
76
6
105.9 Air-Core
76
9
108.8 Air-Core
76
6
111.4 Air-Core
76
9
105.6 Air-Core
76
12
101.9 Air-Core
76
8
101.4 Air-Core
76
11
101.3 Air-Core
76
9
100.4 Air-Core
76
18
105.8 Air-Core
76
6
103.3 Air-Core
76
6
103.4 Air-Core
76
6
111.2 Air-Core
76
12
110.9 Air-Core
76
9
109.5 Air-Core
76
15
112 Air-Core
76
12
111.3 Air-Core
76
9
111.6 Air-Core
76
9
102.8 Air-Core
76
6
99.4 Air-Core
76
6
101.2 Air-Core
76
5
99.9 Air-Core
76
6
100.6 Air-Core
76
6
99.6 Air-Core
76
6
99.6 Air-Core
76
6
99.8 Air-Core
76
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Dip
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
-90
Appendix III
Drillhole intervals used for the material provided for
metallurgical test work
CP_#
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP003
CP004
CP004
CP004
CP004
CP004
CP004
CP004
CP004
CP004
CP004
CP006
CP006
CP006
CP006
CP006
CP006
CP006
CP006
CP006
CP006
CP009
CP009
Hole_ID Sample_ID Depth_From Depth_To
KM1198
671503
2
3
KM1198
671504
3
4
KM1198
671505
4
5
KM1198
671506
5
6
KM1199
671510
1
2
KM1200
671525
4
5
KM1202
671548
0
1
KM1204
671564
1
2
KM1204
671565
2
3
KM1205
671570
1
2
KM1205
671571
2
3
KM1209
671613
4
5
KM1672
676211
2
3
KM1674
676223
2
3
KM1690
676349
2
3
KM1691
676353
1
2
KM1691
676354
2
3
KM1693
676366
2
3
KM1694
676372
2
3
KM1695
676378
2
3
KM1695
676379
3
4
KM1696
676382
0
1
KM1418
673808
2
3
KM1418
673809
3
4
KM1419
673814
2
3
KM1423
673847
2
3
KM1427
673875
4
5
KM1430
673896
4
5
KM1430
673897
5
6
KM1445
674028
2
3
KM1446
674036
4
5
KM1446
674037
5
6
KM1591
675513
7
8
KM1594
675537
4
5
CP009
CP009
CP009
CP009
CP009
CP009
CP009
CP009
CP009
CP009
CP009
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
CP010
KM1595
KM1595
KM1597
KM1598
KM1598
KM1598
KM1598
KM1600
KM1600
KM1601
KM1602
KM1608
KM1608
KM1609
KM1609
KM1610
KM1610
KM1610
KM1611
KM1611
KM1611
KM1622
KM1623
KM1623
675546
675547
675560
675572
675573
675574
675575
675591
675592
675595
675601
675648
675649
675657
675658
675668
675669
675670
675683
675684
675685
675812
675820
675821
5
6
5
8
9
10
11
3
4
1
1
7
8
4
5
6
7
8
6
7
8
7
6
6
6
7
6
9
10
11
12
4
5
2
2
8
9
5
6
7
8
9
7
8
9
8
7
7
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