RCS - South Harz Potash Ld - Ohmgebirge Metallurgical Test Work Results
21/12/2022 10:00
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RNS Number : 4623K South Harz Potash Ltd 21 December 2022
ASX ANNOUNCEMENT
21 December 2022
BENCH SCALE METALLURGICAL TEST WORK CONFIRMS OHMGEBIRGE PROCESSING ROUTE
· Metallurgical test work validates scoping study process flow design
· Targeted K60 grade MOP product confirmed
· Byproduct NaCl produced as chemical grade vacuum salt with a purity of >99%
· Potential Mg(OH)(2) and CaCO(3) process byproducts identified
· Feasibility Study level metallurgical test work scheduled to commence Q1 CY23
South Harz Potash Limited (ASX:SHP) (South Harz or the Company) is pleased to
report that it has received encouraging results from metallurgical test work
completed by K-UTEC AG Salt Technologies (K-UTEC). Test work was performed on
core samples collected from drillholes OHM-01 and OHM-02 completed during 2022
within the Ohmgebirge Mining Licence(1).
Results of the metallurgical test work confirm the process route selected for
the Ohmgebirge Scoping Study is suitable for processing the ore type expected
to be delivered to the mill. Results confirm a preliminary crushing size of
<4mm will enable KCl extraction from the cold leach stage of the process
flow design. The selected processing route is expected to achieve production
of K60 (agriculture sales grade) MOP that is the standard of the global potash
industry.
Test work carried out by K-UTEC in their Sondershausen laboratories, located
close to the project area, considered the quantity and quality of NaCl (salt)
byproduct expected to be produced from future operations. Results verified the
selected process route can produce chemical grade vacuum salt with a purity
exceeding 99%. K-UTEC further reported that additional Mg(OH)(2) and CaCO(3 )
by-products can be extracted via the selected processing route. A
well-established market for chemical grade NaCl, Mg(OH)(2) and CaCO(3) exists
in the NW European area.
Test work informed the composition and character of the resultant waste
products and additionally confirmed that process waste is suitable for use as
mine backfill material. Further metallurgical and backfill test is planned
during 2023.
South Harz Managing Director, Luis da Silva, commented:
"Outcomes from the recent scoping study were based on conventional KCl
processing routes common to the potash industry. We are delighted to report
that metallurgical test work results received from K-UTEC validate the
selected processing route is appropriate for the Ohmgebirge Development
Project. Importantly, results confirm that salable MOP product should be
easily achievable from the samples provided. Metallurgical testing also
indicate that high-grade by-products, including NaCl, are achievable,
providing a significant benefit given South Harz' proximity to well
established European markets. We are looking forward to beginning the next
phase of work in the new year and remain on track with feasibility study
workstreams as we continue to advance the Ohmgebirge Development Project
toward production."
OHMGEBIRGE SCOPING STUDY PROCESS FLOWSHEET
The Ohmgebirge Scoping Study (see ASX release 8th August 2022) selected an
optimal process route of cold leaching followed by evaporation and cooling
crystallisation. The key steps involved in this process flowsheet are:
• Crushing/milling of ore at surface.
• Cold leaching of soluble chloride minerals, KCl and NaCl, at approximately
20-25°C with water.
• Separation of undissolved sulphate minerals and undissolved NaCl and usage as
backfilling material.
• Clarification of leaching liquor and separation of fines (clay, anhydrite).
• Mixing of clarified potash liquor with recycled mother liquor and heating this
mixed brine to boiling temperature.
• Evaporation of water with mechanical vapour compression at approximately
110°C.
• Separation of crystallised NaCl.
• Cooling of hot KCl-NaCl liquor in multi-step vacuum crystallisation plant.
• Separation of obtained KCl-crystalline crop from the mother liquor and
preparation of Muriate of Potash (MOP) with a K(2)O content of 60% to 62%.
• Recycling of cold KCl-NaCl-mother liquor back to the evaporation process.
Figure 1: Block flow diagram of process route selected for the Ohmgebirge
Project.
CRUSHING AND SCREENING
Test work completed on samples collected from recent drillholes OHM-01 and
OHM-02 considered the crushing and milling requirements of the expected ore
from the future mine. The results carried out with a crushing size of <4mm
resulted in sufficient grain separation to enable dissolution of KCl during
the cold leach stage.
DISSOLVING AND WASHING
The test work investigated the dissolving kinetics of KCl and NaCl, and
MgSO(4) and CaSO(4) to highlight the optimal cold leach retention times and
temperature of the cold leach solvent. Test work confirmed that weak NaCl
brine solution is potentially the best solvent option for the cold leach
phase, in comparison to pure demineralised water, which would have an
advantageous effect on future water demands for the processing facility. This
will be further refined during follow on test work.
Characterisation of leach residues was also carried out by K-UTEC, with the
results indicating a waste residue composed of 62% NaCl, 18.4% SO(4) and 3.1%
K(2)O, and 5.3% H(2)O using a weak NaCl bine as a solvent at 25(o)C solvent
temperature. The scoping study envisages that all leach residues will be
backfilled into open spaces in the mine, and characterisation and composition
of the leach residue confirms that this is feasible. Further optimisation work
for the cold leach stage is planned for during 2023 together with
comprehensive slurry backfill test work.
The resultant brine from the cold leach stage then underwent the brine
purification step where NaOH is added to precipitate out Mg(OH)(2) and
Na(2)CO(3) is added to precipitate out CaCO(3). This purification bench scale
test work confirmed the process route as developed in the scoping study. The
test work also confirmed the potential for production of Mg(OH)(2) and CaCO(3)
as additional by-products from the operations.
EVAPORATION AND CRYSTALLIZATION
Evaporation-crystallisation bench scale test work was carried out on purified
leach brine or mother liquor. The scoping study proposed crystallisation of
NaCl be carried out by heating and evaporation and crystallisation of KCl is
carried out by cooling. The composition of the KCl-NaCl-Liquors obtained from
the cold leach and brine purification stage was near saturation with a ratio
between KCl and NaCl approximately 1 to 2. The mother liquor brine was heated
up to ~110(o)C where hot solid-liquid separation of NaCl was achieved at 5 bar
pressure. The mother liquor brine was allowed to cool, resulting in the
crystallisation of KCl, with cold solid-liquid separation of KCl being carried
out under vacuum. Four cycles of brine recirculation were required to achieve
maximum recovery of the KCl and NaCl products. All KCl was crystallised out
with a composition close to 60 % K(2)O without any further washing, which has
been included in the scoping study. Further washing guarantees product
specifications are reached and may be used to increase product grade to K62.
The crystallised NaCl product direct from the crystalliser achieved an initial
grade of ~80 % NaCl, which could satisfy local road de-icing salt requirements
without further washing. The scoping study does include an additional washing
purification step for NaCl and the test work confirmed that the grade and
composition of NaCl after leaching, filter cake washing and drying is ~99.6%
NaCl with 0.4% H(2)O.
KEY PROCESS ATTRIBUTES
The selected process route avoids the disadvantages of conventional hot
leaching and flotation and increases recoveries of the components of the raw
salt. It can efficiently handle the polymineralic ore type found at Ohmgebirge
by separating out the easily soluble chloride minerals (KCl and NaCl) from
insoluble material and sulphate minerals at the cold leach stage. As noted in
the scoping study, unwanted dissolved salt components in the resultant brine
can be removed by precipitation of calcium carbonate and/or magnesium
hydroxide with soda ash and/or caustic soda when added in the brine
purification step prior to evaporation-crystallisation. The precipitates are
freely removed by sedimentation and filtration.
Other key attributes identified during initial testing include:
· Bleed streams can be either monetized as other products or handled
in the backfill.
· The chosen process, proven historically, maximizes the KCl recovery
in similar ore bodies.
· That a simple process route optimises the number of employees.
· The chosen route requires a lower demand for steam in heating
process
· The selected process consumes less energy and other auxiliary
materials.
Over the various unit operations, the predicted recoveries were identified,
and the results are in the range quoted in the scoping study. To clearly show
the overall recovery from the ore, including the volumes of the waste streams
to be backfilled, pilot scale testing is planned during 2023. Preliminary mass
and energy balances will be included in pilot scale test work to inform
equipment sizing and estimating for the PFS planned for completion during
2023.
Ohmgebirge Mineral Resource Estimate
The Ohmgebirge Mineral Resource is 338 Mt at 12.9% potassium oxide (K(2)O)
totalling approximately 44 Mt of contained K(2)O (see Table 1). This estimate
comprises 290 Mt of Sylvinite (key focus seam for development) grading 13.5%
K(2)O (split approximately 89% Indicated and 11% Inferred categories) and 48
Mt of Carnallitite at 9.8% K(2)O (100% Inferred).(2)
Table 1: JORC Ohmgebirge Mineral Resource estimate (July 2022)
Mineralised Seam Categorisation Tonnage (Mt) K(2)O (%) K(2)O (Mt)
Sylvinite Indicated 258 13.54 35
Inferred 32 12.85 4
Sylvinite total 290 13.47 39
Carnallite Inferred 48 9.81 5
Carnallitite total 48 9.81 5
TOTAL RESOURCE Indicated and Inferred 338 12.91 44
Minimum cut‐off grade ≥5% K2O; 15% geological loss applied to account for
potential unknown geological losses.
Figure 2: Ohmgebirge Mining Licence area showing the approximate location of
historic drillholes and the twin confirmatory holes, OHM-01 and OHM-02.
Competent Persons Statement - Metallurgical Results
The information in this announcement that relates to the 2022 Metallurgical Test Work Results for Ohmgebirge and is based on test work completed by K-UTEC under the supervision of Mr. Stephan Kaps, who is a Fellow of the Institute of Mining and Metallurgy. Mr. Kaps is independent of South Harz Potash and is a consulting Chemical Engineering and Head of Engineering at K-UTEC. Mr Kaps has sufficient experience which is relevant to metallurgical processing of the style of potash 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. Kaps consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
Competent Person Statement - Resources & Exploration Results
Elizabeth de Klerk M.Sc., Pr.Sci.Nat., SAIMM., Micon's Senior Geologist and Competent Person visited the South Harz Potash project on four separate occasions, from the 12th to 16th February, the 6th to 8th March 2018, from 15th to 17th October 2019 and specifically to the Ohmgebirge drill sites on 5(th) to 8(th) April 2022. The most recent visit included meetings with drilling supervisors and potash consultants "Ercosplan" and an inspection of the analytical laboratory facilities at K-UTEC AG Salt Technologies ("K-UTEC") in Sondershausen, Germany.
Elizabeth de Klerk is the Managing Director and Senior Geologist of Micon International Company Limited (UK) has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which she 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".
Mrs de Klerk consents to the inclusion in this document of the matters based on this information in the form and context in which it appears.
This ASX release has been approved by Managing Director, Luis da Silva.
Investor and media enquiries
Luis da Silva Michael Vaughan Justine James / Matthew Young
Managing Director Fivemark Partners Alma PR
South Harz Potash Ltd +61 422 602 720 +44 203 405 0205
info@southharzpotash.com michael.vaughan@fivemark.com.au shp@almapr.co.uk
About South Harz
South Harz Potash (ASX: SHP) (South Harz) is a potash exploration and development company with its flagship project located in the South Harz Potash District region of Germany, midway between Frankfurt and Berlin.
The South Harz Project hosts a globally large-scale potash JORC (2012) Mineral Resource estimate of 5 billion tonnes at 10.6% K(2)O of Inferred resources and 258 million tonnes at 13.5% K(2)O of Indicated Resources across four wholly-owned project areas located favourably within central Europe.(2) This comprises three perpetual potash mining licences, Ohmgebirge, Ebeleben and Mühlhausen-Nohra, and two potash exploration licences, Küllstedt and Gräfentonna, covering a total area of approximately 659km².
With strong established infrastructure proximate to the key European market, the South Harz Project is well positioned to enable rapid economic development across multiple deposits.
South Harz Potash: Growing a responsible potash business in the heart of Germany
www.southharzpotash.com (http://www.southharzpotash.com)
1. Refer ASX Announcements 29 April 2022 and 8 June 2022. South Harz
is not aware of any new information or data that materially affects the
information included in these ASX releases.
2. Refer to South Harz ASX release dated 12 July 2022 for full Mineral
Resource estimate details. In accordance with ASX Listing Rule 5.23, the
Company is not aware of any new information or data that materially affects
the information included in this release and the Company confirms that, to the
best of its knowledge, all material assumptions and technical parameters
underpinning the estimates in this release continue to apply and have not
materially changed.
GLOSSARY
% - Percent
°C - degree Centigrade
Ca - Calcium
CaCO(3 )- Calcium Carbonate
CaSO(4) - Calcium sulphate
ASX - Australian Stock Exchange
CP - Competent Person
€ - Euro
h - Hour(s)
Insols - Acid insoluble material
K - Potassium
K(2)O - Potassium oxide
KCl - Potassium chloride
K60 - Standard grade MOP product (K60
refers to 60% K(2)0 equivalent to 95% KCl)
kg - kilogramme
km - kilometre
km(2) - square kilometre
kt - thousand tonnes
m - metre
Mg - Magnesium
MgCl(2) - Magnesium chloride
Mg(OH)(2) - Magnesium hydroxide
MgSO(4) - Magnesium sulphate
MOP - Muriate of Potash
Mt - million tonnes
Mt/a - million tonnes per year
Na - Sodium
NaCl - Sodium chloride (salt)
QP - Qualified Person
Report - technical report
ROM - Run of Mine
SO(4) - sulphates
Südharz - South Harz
t - tonne
t/a - tonnes/year
t/d - tonnes/day
t/h - tonnes/hour
Wt% - Weight percent
y - Year(s)
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