Cardinal Resources Limited (ASX/TSX: CDV) is pleased to announce a positive development with respect to its metallurgical optimisation testwork activities. As a result of positive leach results, which are expected to enhance the project economics, further laboratory testwork has been initiated.
- Positive leach recovery results reported from Aachen TM pilot scale testwork
- AachenTM is a relatively simple, proven process being used by a number of successful gold producers globally and specifically in Africa. These operations have consistently demonstrated an uplift in gold recoveries with AachenTM
- AachenTM results on Namdini flotation concentrate indicates the following potential improvements:
- increased gold recovery (Table 1)
- coarser regrind size compared with the current flowsheet
- reduced power consumption (ie lower installed power requirements and Opex)
- improved mass transfer of oxygen and reactivity of reagents
- reduced reagent consumption leading to reduced operating costs
- expected reduction of both Capex and in particular, Opex
- Cardinal has already tested 4,447 kg (>4 tonnes) comprising 7 pilot scale composites from 47 drill holes (Table 2) across the entire deposit. Cardinal is finalizing the testwork programme with a further 2,310 kg (>2 tonnes) of samples from an additional 24 drill holes
- Final AachenTM testwork is in progress to further support the results received to date for potential inclusion into the Namdini Feasibility Study
- Peter Lotz, Gold Process & Environment Manager, Maelgwyn Mineral Services Africa, stated:
- “Our AachenTM process is currently deployed at 9 different mine sites in 6 countries, with the longest service life of over 10 years on one of the largest bullion producers within the African continent.
- “We’ve seen our process increase gold recoveries between 2% and 19% in gold producing operations. Former Randgold Resources (now Barrick), a major client of MMS, is using AachenTM equipment at its Loulo and Morila mines in Mali, at its Tongon operation in Côte d’Ivoire, and at the Kibali gold mine in the Democratic Republic of Congo.
- “We look forward to our continuing work with Cardinal in this regard”.
- Cardinal’s Chief Executive Officer / Managing Director, Archie Koimtsidis stated:
- “These highly encouraging results from the metallurgical optimisation programme are potentially an opportunity to further enhance the Namdini project financial outcomes and should be incorporated into the process flowsheet being designed by Lycopodium.
- “The metallurgical optimisation test results recently received and evaluated show promising recovery, capital and operating cost improvements, which can be achieved over and above the current outcomes justifying incorporation into the Feasibility Study”.
Cardinal has recently completed its current testwork to consider the introduction of an AachenTM system into the Namdini process flow sheet which is being established by Lycopodium. The testwork has been completed at the Maelgwyn Mineral Services Africa (MMSA) metallurgical laboratory in South Africa.
The base premise of the process is to scour the mineral surfaces and maximise oxygen transfer to the ore slurry prior to leaching, which enhances leach kinetics, resulting in improved recovery of gold. It is a relatively simple, proven process already being used at 9 gold producing mines.
In addition to a potential increase in gold recovery (and therefore a potential uplift to annual gold production rates), there are typically power and reagent savings (Opex savings) and installed power requirements (Capex savings) that can be realised.
Testwork on integrating the AachenTM process into the Namdini flowsheet demonstrated potential to increase recoveries for the Life of Mine study and also suggested an increase in the grind size from sub 10 microns (µm) into the coarser range of 20 to 45 microns (µm) for certain lithologies. Further testwork is ongoing to consider the optimal grind size and target recovery, with detailed cost/benefit analysis underway as part of the programme.
The AachenTM process has also been successfully used for cyanide destruction, post leach circuit, which will also be analysed for further Opex and Capex savings.
Table 1: Namdini AachenTM Leach Testwork Results – Life of Mine (LOM) Samples1
Regrind Size (P90 µm) | Metavolcanics (MVO) | Granite (GRA) | Diorite (DIO) | |||
AachenTM Leach Recovery2 % | Range of possible overall | AachenTM Leach Recovery2 % | Range of possible overall | AachenTM Leach Recovery2 % | Range of possible overall | |
5 µm | 91 - 95 | 84 - 90 | 92 - 96 | 84 - 91 | 90 - 96 | 83 - 91 |
9 µm | 90 - 96 | 82 - 91 | 88 - 96 | 81 - 91 | 90 - 94 | 82 - 89 |
45 µm | 84 - 88 | 77 - 84 | 95 - 97 | 87 - 92 | 93 - 95 | 86 - 90 |
75 µm | 73 - 75 | 67 - 71 | 76 - 82 | 70 - 78 | 75 - 86 | 69 - 82 |
Notes
Results represent pilot scale composites for each lithology (MVO, GRA, DIO)
- Range of leach recoveries at incremental passes through the Aachen process
- Range of possible overall recovery, calculated by multiplying Aachen leach recovery range by typical flotation recovery range (92-95%), which are results indicated in Cardinal’s PFS NI 43-101 (25 October 2018)
Table 2: Namdini AachenTM Leach Testwork – Summary Total of Samples Submitted by Cardinal
| Samples Mass (kg) | Number of Drill Holes | Number of Intervals (1m) | Number of Final Leach Data Points1 |
TOTAL | 4,447 | 47 | 2,048 | 84 |
Note 1: Leach data points are related to various regrind sizes for the total 7 Starter Pit and Life of Mine pilot scale composites
Figure 1: Shows the drill hole locations for the composites of the AachenTM testwork
Next Steps
As a result of the positive leach results which are expected to enhance Namdini Project economics, further testwork samples have been submitted. All aspects of the Feasibility Study are on track for delivery this quarter, however, Cardinal is reverting to the original Q3 - 2019 Feasibility Study publication timeline in respect of the Company’s flagship Namdini Gold Project in Ghana so that final testwork results from the AachenTM process can be incorporated.
Study Manager Lycopodium continues to accelerate the full integration of all project disciplines and to coordinate the efforts of our other study partners.
Lycopodium is a highly respected mining services company with over 25 years’ global experience in the minerals industry, designing and building large-scale mines, processing plants and associated infrastructure, particularly in Africa and West Africa.
Project Development Partners
COMPANY | ROLE |
Lycopodium | Feasibility Study Managers. Process plant and associated infrastructure. Capital and Operating cost estimation and compilation of the JORC and NI 43-101 Technical reports |
Golder Associates | Mine planning and optimisation, pit design and mine scheduling, Geotechnical, Hydrology and Hydrogeological engineering |
Orway Minerals Consultants | Comminution data analysis, crushing and grinding circuit option study |
ALS Laboratory (Perth) | Metallurgical testwork to support the process design criteria |
Knight Piésold Consulting | Tailings Storage Facility and selected infrastructure design |
Independent Metallurgical Operations | Metallurgical testwork management, analysis and process flowsheet development |
MPR Geological Consultants | Mineral Resource modelling of the Namdini Deposit |
Orefind | Geology and deposit structural genesis |
Sebbag Group International | Mine Design Review |
NEMAS Consult | Environmental Impact Assessment Study |
Whittle Consulting | Enterprise Optimisation of the Namdini Project |
Maelgwyn Mineral Services Africa | AachenTM process metallurgical optimisation |
BDO Advisory | Financial Model Integrity & Reviewer (PEA, PFS and FS) |
ABOUT MAELGWYN – AachenTM Process
Maelgwyn Mineral Services (MMS) is a world leader in the development and implementation of innovative cost- effective technologies and processes in the field of mineral, chemical and waste processing. It has had many patents granted and has won a number of national innovation awards for its process.
The AachenTM process is one of Maelgwyn’s primary business metallurgical technologies which can be tested at their fully certified and commercial laboratory in South Africa. The AachenTM process can be tested at bench and pilot scale in this laboratory.
The AachenTM process uses a pipe shear device designed to improve oxidation of slurries using oxygen. It uses a slot aerator to introduce micron-sized (200µm) oxygen bubbles into the device which has different chambers separated by orifice plates creating a highly efficient contact of oxygen to the slurry. The equipment is especially efficient for high- rate oxidation of sulphides which is ideal for Namdini’s ore since the gold is particulate and occurs as free gold, in fractures in pyrite or in pyrite grains.
The objective is to increase efficient utilisation of the oxygen and as a consequence of the significant increase in real-time oxidation it could allow grind sizes to be coarser thus reducing overall power and reagent costs. The device contains no moving parts, and is designed to withstand erosive effects of mineral slurries.
Figure 2: AachenTM Equipment Illustrations
MMS have commissioned more than 60 of the AachenTM units on the African continent, working with several high-profile mining companies across several jurisdictions.
Former Randgold Resources (now Barrick), a major client of MMS, is using AachenTM oxidation technology at its Loulo and Morila mines, in Mali, at its Tongon operation, in Côte d’Ivoire, and at the Kibali gold mine, in the Democratic Republic of Congo.
MMS has also provided the process to Liberian gold miner Avesoro Resources’ (formerly Aureus Mining’s) New Liberty gold mine and to South African gold miner Pan African Resources at its Barberton Mines operation, where the Aachen units are used in the cyanidation circuit and are also used to support the cyanide detoxification processes.
MMSA is also working on several tailings storage facility reclamation projects in South Africa and aims to use Aachen oxidation technology in the various reclamation processes.
Figure 3: AachenTM Installation - Gold Mine Example 1
Figure 4: AachenTM Installation – Gold Mine Example 2
Figure 5: AachenTM Installation – Gold Mine Example 3
On-site Due Diligence
Cardinal Resources’ management undertook a due diligence review of the AachenTM process in March 2019. The due diligence review included a site visit to the Maelgwyn laboratory facility in Northcliff South Africa followed by a site inspection of two AachenTM devices installed at a gold mine operating in Southern Africa.
A summary of observations made during the site visit is highlighted below:
- There are 63 AachenTM units currently employed at 9 sites in Africa.
- Scale up from laboratory to full production has generally shown greater improvements. Generally, a 5% recovery improvement in the laboratory can translate into 7 or 8% in full-scale operation.
- Slurry input to the unit is generally ~2 m/s and the velocity through the contact zone is ~10 m/s. Oxygen is introduced with micron-sized bubbles (200µm), with + 10 m/s velocity.
- Maelgwyn expect 4,000 to 5,000 hours service between maintenance intervals based on operational experience.
In general terms, high shearing of slurry particles and high velocity of oxygen, results in improved kinetics by scouring the particle surfaces and accelerating the oxidation of the sulphide species which then allows for less residence time and less reagent requirements within the leaching circuit.
AachenTM Testwork Procedure
The scope of work for the pilot scale experiments is outlined in the diagram below. The seven (7) bulk composite sample ID’s were sequentially processed via primary milling, to a grind specification of 50% passing 212 μm, followed by Knelson gravity separation and secondary milling to 80% passing 106 μm. The milled gravity tails were subjected to froth flotation to generate concentrate for the subsequent AachenTM testwork series.
Figure 5: AachenTM Testwork: Procedure – Pilot scale
Summary of the AachenTM testwork results on Namdini samples:
Maelgwyn’s AachenTM Process is showing encouraging results on a number of fronts with the most significant being:
-
- Recovery improvement
- Leach kinetics
- Potential increase in grind size without compromising recovery
- Power and reagent consumption reduction, specifically oxygen and cyanide
All the above points could result in project economic benefits by reducing OPEX and CAPEX whilst improving gold recovery which has provided a clear path forward for Cardinal and the Aachen™ process.
Position of Aachen™ equipment within Namdini Flowsheet
AachenTM will be deployed after the flotation concentrate regrind circuit as indicated in Figure 6. The process throughput is relatively small since only flotation concentrate is treated through the device.
Figure 6: Position of Aachen™ device in Namdini Flowsheet
ABOUT CARDINAL
Cardinal Resources Limited (ASX/TSX: CDV) is a West African gold exploration and development Company that holds interests in tenements within Ghana, West Africa.
The Company is focused on the development of the Namdini Project with a gold Ore Reserve of 5.1Moz (0.4 Moz Proved and 4.7 Moz Probable) and a soon to be completed Feasibility Study.
Exploration programmes are also underway at the Company’s Bolgatanga (Northern Ghana) and Subranum (Southern Ghana) Projects.
Cardinal confirms that it is not aware of any new information or data that materially affects the information included in its announcement of the Ore Reserve of 3 April 2019. All material assumptions and technical parameters underpinning this estimate continue to apply and have not materially changed.
For further information contact:
Archie Koimtsidis Alec Rowlands
CEO / MD IR / Corp Dev
Cardinal Resources Limited Cardinal Resources Limited
P: +61 8 6558 0573 P: +1 647 256 1922
Cannings Purple
Andrew Rowell or Peta Baldwin
E: [email protected]
E: [email protected]
In Europe:
Swiss Resource Capital AG
Jochen Staiger
[email protected]
www.resource-capital.ch
This release has been independently reviewed by CSA Global (Perth) for JORC Code Compliance.
CSA Global have not verified the results presented.
Competent / Qualified Person Statement
All production targets for the Namdini Gold Mine referred to in this report are underpinned by estimated Mineral Resources and Ore Reserves which were prepared by competent persons and qualified persons in accordance with the requirements of the JORC Code and National Instrument 43-101- Standards of Disclosure for Mineral Projects (“NI43-101”), respectively (ASX/TSX press release dated 3 April 2019).
Scientific and technical information contained in this press release has been reviewed and approved by Mr. Daryl Evans, Independent Metallurgical Operations Pty Ltd (IMO), who is a ‘qualified person’ as defined by National Instrument 43‐101 Standards of Disclosure for Mineral Projects (“NI43‐101”). Mr. Evans holds a Qualified Professional status being a Fellow of the Australasian Institute of Mining and Metallurgy (FAusIMM). IMO is an independent consulting firm appointed by Cardinal. IMO and Mr. Evans consent to the inclusion of the matters in this report of the statements based on the information in the form and context in which it appears.
The scientific and technical information contained in this press release is based on information compiled and reviewed by Mr. Richard Bray, a Competent Person who is a Registered Professional Geologist with the Australian Institute of Geoscientists and a full-time employee of Cardinal Resources Ltd. Mr. Bray has sufficient experience which is relevant to the style of mineralization and type of deposit under consideration and to the activity which he has undertaken to qualify as a Competent Person as defined in the JORC Code 2012 and is a qualified person for the purposes of NI43-101. Mr. Bray is a full-time employee of Cardinal and holds equity securities in the Company. Mr. Bray has consented to the inclusion of the matters in this report based on the information in the form and context in which it appears.
ASX Listing Rule 5.23.2
The Company confirms it is not aware of any new information or data that materially affects the information included in this report relating to exploration activities and all material assumptions and technical parameters underpinning the exploration activities in those market announcements continue to apply and have not been changed. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcements. Cardinal confirms that it is not aware of any new information or data that materially affects the information included in its announcement of the Ore Reserve of 3 April 2019. All material assumptions and technical parameters underpinning this estimate continue to apply and have not materially changed.
Disclaimer
This ASX / TSX press release has been prepared by Cardinal Resources Limited (ABN: 56 147 325 620) (“Cardinal” or “the Company”). Neither the ASX or the TSX, nor their regulation service providers accept responsibility for the adequacy or accuracy of this press release.
This press release contains summary information about Cardinal, its subsidiaries and their activities, which is current as at the date of this press release. The information in this press release is of a general nature and does not purport to be complete nor does it contain all the information which a prospective investor may require in evaluating a possible investment in Cardinal.
By its very nature, exploration for minerals is a high‐risk business and is not suitable for certain investors. Cardinal’s securities are speculative. Potential investors should consult their stockbroker or financial advisor. There are a number of risks, both specific to Cardinal and of a general nature which may affect the future operating and financial performance of Cardinal and the value of an investment in Cardinal including but not limited to economic conditions, stock market fluctuations, gold price movements, regional infrastructure constraints, timing of approvals from relevant authorities, regulatory risks, operational risks and reliance on key personnel and foreign currency fluctuations.
Except for statutory liability which cannot be excluded and subject to applicable law, each of Cardinal’s officers, employees and advisors expressly disclaim any responsibility for the accuracy or completeness of the material contained in this press release and excludes all liability whatsoever (including in negligence) for any loss or damage which may be suffered by any person as a consequence of any information in this Announcement or any error or omission here from. Except as required by applicable law, the Company is under no obligation to update any person regarding any inaccuracy, omission or change in information in this press release or any other information made available to a person nor any obligation to furnish the person with any further information. Recipients of this press release should make their own independent assessment and determination as to the Company’s prospects, its business, assets and liabilities as well as the matters covered in this press release.
Forward‐looking statements
Certain statements contained in this press release, including information as to the future financial or operating performance of Cardinal and its projects may also include statements which are ‘forward‐looking statements’ that may include, amongst other things, statements regarding targets, anticipated timing of the feasibility study (FS) on the Namdini project, estimates and assumptions in respect of mineral resources and anticipated grades and recovery rates, impact of the potential implementation of the AachenTM process to the Namdini gold project, production and prices, recovery costs and results, capital expenditures and are or may be based on assumptions and estimates related to future technical, economic, market, political, social and other conditions. These ‘forward–looking statements’ are necessarily based upon a number of estimates and assumptions that, while considered reasonable by Cardinal, are inherently subject to significant technical, business, economic, competitive, political and social uncertainties and contingencies and involve known and unknown risks and uncertainties that could cause actual events or results to differ materially from estimated or anticipated events or results reflected in such forward‐looking statements.
Cardinal disclaims any intent or obligation to update publicly or release any revisions to any forward‐looking statements, whether as a result of new information, future events, circumstances or results or otherwise after today’s date or to reflect the occurrence of unanticipated events, other than required by the Corporations Act and ASX and TSX Listing Rules. The words ‘believe’, ‘expect’, ‘anticipate’, ‘indicate’, ‘contemplate’, ‘target’, ‘plan’, ‘intends’, ‘continue’, ‘budget’, ‘estimate’, ‘may’, ‘will’, ‘schedule’ and similar expressions identify forward‐looking statements.
All forward‐looking statements made in this press release are qualified by the foregoing cautionary statements. Investors are cautioned that forward‐looking statements are not guarantees of future performance and accordingly, investors are cautioned not to put undue reliance on forward‐looking statements due to the inherent uncertainty therein.
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