REG - Harena Resources PLC - High Recoveries of Critical Magnet Metals

Harena ResourcesAnnouncement

16/04/2025 07:30

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RNS Number : 2550F  Harena Resources PLC  16 April 2025

 

16 April 2025

 

Harena Resources Plc

 

("Harena" or the "Company")

 

Ampasindava Confirms High Recoveries of Critical Magnet Metals via Low-Impact
Heap Leach Processing

Harena (LSE:HREE) is pleased to report metallurgical test results from its 75%
owned Ampasindava Rare Earths Project in Madagascar. The work confirms that
ionic clay-hosted rare earth elements (REEs) from Ampasindava - including the
strategically critical magnet metals Neodymium (Nd), Praseodymium (Pr),
Dysprosium (Dy) and Terbium (Tb) - can be recovered efficiently using
low-impact heap leach processes such as salt water or standard ammonium
sulphate solutions.

This result supports the Company's goal of developing a technically robust,
environmentally responsible, and geopolitically independent supply of magnet
metals essential to the global defence, energy, and technology sectors.

Highlights:

·    REEs at Ampasindava are readily recoverable through simple ion
desorption, with high extraction rates achieved using a ammonium sulphate
leach in low-acid conditions.

·    Main extractions were approximately 88% Nd, 73% Dy, 67% Y, 86% La,
with low levels of gangue, thorium (Th) and uranium (U) supporting a clean
environmental profile.

·   SGS Lakefield testwork using a pH 5 ammonium sulphate
solution delivered strong results, including 87% Nd, 88% Pr, 71% Dy, 75% Tb
and 63% Y

·    Encouragingly optimal column heap leach test, over 218 hours,
demonstrated recoveries of 88% Nd, 86% Pr, 73% Dy, 79% Tb and 67% Y using
Ammonium Sulphate at a pH of 4.

·    Low value/high bulk Cerium demonstrated minimal recovery, a
significant benefit in production of a high-grade magnet metal concentrates or
carbonates.

 

Joe Belladonna, Managing Director, commented:

"While early days in the programme the high rare earth recovery results
achieved in the SGS Lakefield test work are very encouraging.  This
demonstrates that the process to be employed at Ampasindava will be
environmentally and ecologically friendly. Furthermore, the low-risk process,
simple reagents utilised and no requirement for a tailing storage facility
should benefit the economic and technical viability of Ampasindava."

"With the current geopolitical environment, the race to secure heavy rare
earth feed stocks for defence and new energy applications is accelerating.
Projects that can demonstrate both technical viability and alignment with
Western supply chain priorities are increasingly in focus. Ampasindava's
combination of critical magnet metals, clean extraction, and independence from
Chinese processing gives us a timely opportunity to contribute to a more
resilient global supply chain."

 

 

Summary of Key Technical Information

Metallurgical test work was carried out on 54 bulk and discrete samples of the
regolith clays over several campaigns by the University of Toronto (UoT),
Outotec and SGS Lakefield. The SGS Lakefield samples were sourced from test
pits and were taken between 1m and 10m below surface and weighed between 6kg
and 35kg each. Some were used separately and others amalgamated into several
representative bulk samples including a Master Clay Composite.

The testing culminated in 12 optimum eluant tests and follow on column tests
for the use of salt water or ammonium sulphate as primary leaching agent.
Column tests simulate heap leaching conditions.

Importantly, the results of these tests determined that Ampasindava ionic clay
hosted rare earth elements are released from their adsorption bond liberally
with a low intensity pH4 to pH5 and a residence time of around 10 days.

 

Column Tests

At SGS Lakefield, after the series of shaking tests were finalised two column
(heap) leach tests were designed. The goals were to study the physical
behaviour of the column (irrigation, compaction and to confirm the results
from the shaking tests. Based on the Optimum Eluant Tests results Column 1 was
run using 1M ammonium sulphate solution adjusted to pH 4 as eluant while
Column 2 used 1M sodium chloride solution adjusted to pH4. Standard test
conditions included:

•     Feed consisting of Master Clay Composite;

•     Irrigation rate of 15 L/h/m2 (equivalent to 0.5 mL/min);

•     Room temperature;

•     Running time of 218 hours;

•     DI water washing at 60 L/h/m2 for 24 hours.

 

Before charging to the column, the feed for each column was agglomerated using
their respective eluant solution as binding agent. This was achieved by
spraying eluant onto the feed and rolling the sprayed clay on a plastic sheet
in doses until the feed began to form agglomerates of material that were not
immediately broken by physical force. Once sufficiently wet, the feed was
allowed to air dry.

Once agglomerated, the feed was slowly added to the columns to avoid breaking
the agglomerates; columns were tapped during this process to ensure uniform
packing of the column. Each column was weighed before and after adding the
feed as well as at the end of the test. Eluant addition was started
immediately, considered as time zero. Discharge was not controlled, i.e. it
was not pumped out of the columns.

Overall average feed and discharge rates were calculated using the mass
differences on the weighed containers. The average eluant feed rate was
slightly lower than target at 14.1 L/h/m2 and 12.8 L/h/m2 for Column 1 and
Column 2, respectively. This is due to the drift inherent in any pump
calibration curve, exacerbated by the very slow flowrate required.

The average discharge rate (taken from the time of first discharge onwards)
was calculated to be 13.6 L/h/m2 and 12.8 L/h/m2 for Column 1 and Column 2
respectively, slightly less than the feed rate due to entrainment of eluant
within the column.

After 218 hours of running time the addition of eluant was stopped and the
columns were allowed to drain. Once they stopped draining the solids were
washed with distilled water at an irrigation rate of 60 L/h/m2.

SGS Lakefield Conclusions

Following a series of tests investigating the extraction of rare earth metals
from the mineralization (REE Clay) samples from Ampasindava. The main
conclusions were are as follows:

•     Rare earth metals can be extracted from REE clay by ion desorption
using an ammonium sulphate or sodium chloride solution as eluant. Main
extractions were around 88% Nd, 73% Dy, 67% Y, 86% La. It was also confirmed
that most of the gangue material as well as Th and U remain in the solids and
do not follow the REE into solution.

 

•     It was determined that shaking tests with a single contact and
three eluant washes was the optimum and most practical method to evaluate REE
extraction from REE clay samples. This method of extraction was run for 60
minutes and at room temperature making it very simple and feasible for running
a large number of samples.

 

•     A solution of 1 mol/L ammonium sulphate at pH 4.0 produced the
maximum REE extractions and still achieved low gangue material extractions.
When using sodium chloride, a concentration of 1 mol/L and an adjusted pH of
4.0 were determined as optimum conditions for high REE extractions and low Th
and U extractions.

 

•     Different eluant:ore ratios were tested in an extraction isotherm
style series of tests. The data showed that despite low eluant:ore ratios,
high REE extractions can be obtained. The data shows that a simple counter
current desorption process should be capable of producing high grade REE
liquors while at the same time producing low residue levels (i.e. high
extraction).

 

•     Heap leaching was simulated in a series of small column leach
tests. Two columns were operated for 218 hours; Column 1 was run using a
solution of 1M ammonium sulphate at pH 4 as eluant while Column 2 ran with a
solution of 1M ammonium sulphate at pH 4. The irrigation rates were 14.1 and
12.8 L/h/m2 for Column 1 and 2, respectively. Maximum REE extractions were
accomplished in Column 1 using ammonium sulphate (88% Nd, 73% Dy, 67% Y, 86%
La). Column 2 (sodium chloride) led to lower extractions of 78% Nd, 68% Dy,
63% Y and 82% La. Not only were the extractions lower in Column 2 they also
took more time to achieve those extractions as is shown in Figure 6. Gangue
extractions as well as Th and U extractions remained low in Column 1 and
Column 2.

 

 

 

Table 1. Heap Leaching (Column Test) Main Parameters

 

 

 

 

 

 

 

Table 2. Column 1 - Ammonium Sulphate Solution - (NH(4))(2)SO(4) Extraction %

 

REE extractions were higher in Column 1 (ammonium sulphate) than in Column 2
(sodium chloride); main metal extractions were 88% Nd, 73% Dy, 67% Y, 86% La
for Column 1, and 78% Nd, 68% Dy, 63% Y and 82% La for Column 2.

Table 3. Column 2 - Sodium Chloride Solution - NaCl Extraction %

 

 

 

References:

1.    Independent Specialist Report by SGS - Ampasindava Rare Earths
Project - August 20 2024

 

Contact

 Harena Resources                      www.harenaresources.com.au (https://harenaresources.com.au/)
 Joe Belladonna/Allan Mulligan         +44 (0)1624 681 250

                                       info@harenaresources.com.au (mailto:info@harenaresources.com.au)

 Tavira Financial                      +44 (0)20 7330 1833

 Jonathan Evans/Oliver Stansfield

 Flowcomms (Investor Relations)        +44 (0) 7891 677 441

 Sasha Sethi                           sasha@flowcomms.com

 Twitter                               www.x.com/HarenaResources (http://www.x.com/HarenaResources)
 LinkedIn                              www.linkedin.com/company/harenaresources
                                       (https://www.linkedin.com/company/harenaresources/)

 

Notes to Editors

 

Harena Resources is a rare earths exploration and development company focused
on the Ampasindava Ionic Clay Rare Earth Project in Madagascar (Harena's
interest is 75%). The project hosts one of the largest ionic clay rare earth
deposits outside of China, with significant concentrations of high-value
magnet metals. Harena is committed to low-impact, high-recovery mining,
providing a sustainable supply of critical minerals for the global energy
transition and military defence industries.

Forward-Looking Statements This announcement contains forward-looking
statements that involve risks and uncertainties. Actual results may differ
materially from those expressed or implied in such statements.

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