African Gold Group Confirms Both Oxides and Sulphides to be Incorporated Into Updated Feasibility Study
TORONTO, July 15, 2021 (GLOBE NEWSWIRE) — African Gold Group, Inc. (TSX-V: AGG) (“AGG” or the “Company”) is pleased to announce final metallurgical test results from its comprehensive sulphide testwork programme. Results of the testwork programme will be incorporated into an updated definitive feasibility study (DFS). The final phase of the testwork programme was to undertake variability testing to determine the optimal process route of the ore across the extent of the ore body. The Company is continuing its work on updating mineral resource estimates (MRE) and an updated definitive feasibility study to incorporate additional drilling and the sulphide testwork results.
Highlights from the metallurgical testing include:
- Gravity gold recovery values vary from 40.40% to 73.18% with an 85th percentile of 61.52%. These results indicate that the sulphide ore at Kobada is amenable to gravity recovery.
- Overall gold dissolution at 93.87% (85th percentile) confirms initial findings that consistent overall gold dissolution of above 90% can be achieved on the sulphide ore.
- Cyanide consumption values vary from 0.14 kg/t to 0.46 kg/t with an 85th percentile of 0.34 kg/t, indicating low cyanide consumption of the sulphide ore.
- Lime consumption values vary from 0.23 kg/t to 0.31 kg/t with an 85th percentile of 0.30 kg/t, confirming low lime consumption of the sulphide ore.
Danny Callow, CEO, African Gold Group states:
“The finalisation of our comprehensive sulphide metallurgical testwork programme, culminating in the variability testwork, shows us that sulphides at the Kobada gold project can be treated through a gravity and CIL process. The process design on gravity and CIL for the oxides as presented in our July 2020 Definitive Feasibility Study is suitable for treating the sulphides as well, and this will allow us to add substantial resources to our overall resource base. The sulphides are free-milling, show excellent recoveries and consume low amounts of lime and cyanide, making this a very efficient operating cost process.”
“These results will feed into our updated DFS, allowing us to incorporate sulphides into the life of mine plan and we believe will add additional reserve ounces to our economic models. The wider testwork programme has been highly successful and confirms Kobada’s excellent potential as a future new mine in Mali. We are looking forward to delivering an updated study in Q3-2021.”
The comprehensive metallurgical testing program was conducted by Maelgwyn South Africa (“MSA”) on composite samples from all defined mineral zones (north, south, and central domains) of the main shear zone. The final stage of this process, the variability testing has proven the consistency of being able to treat the sulphides across the extent of the ore body.
Kobada Sulphides Variability Recovery Testwork Results
Upon completion of recovery optimization testwork on a composite sample, the optimum conditions selected were tested on variability samples to determine if the selected process route and optimum conditions selected are applicable across the entire ore body. Six variability samples were selected from the North, South and Central zones. Table 1-1 below shows samples used to make up the variability samples.
|Sample ID||Weight (kg)||Sub samples used for compositing|
|Central||5.72||KB20 – P2-12|
|North||6.93||KB20 – P4A-3
KB20 – P4A-4
KB20 – P4A-25
KB20 – P4A-35
|South 1||15.20||KB19 – P1-3
KB19 – P1-4
KB19 – P1-7
KB19 – P1-11
KB19 – P1-12
|South 2||21.50||KB19 – P1-20
KB19 – P1-21
KB19 – P1-22
KB19 – P1-31
|South 3||9.31||KB19 – P2-1
KB19 – P2-4
KB19 – P2-5
|South 4||27.78||KB19 – P2-6|
Table 1-1: Variability Sample Selection
The selected process route on the oxide ore was gravity followed by cyanidation. Initial scouting testwork on the sulphide ore using the same process route as for the oxides showed gold recovery above 90% with low cyanide and lime consumptions. Therefore, the selected recovery process for the sulphides was gravity followed by intensive cyanidation on the gravity concentrate and cyanidation on the gravity middlings and tails. The following optimum leach conditions were selected for the sulphide ore:
- Grind: 80%-75µm.
- Leach process: Carbon in leach (CIL).
- Cyanide addition – 1kg/t.
- Lab residence time – 12 to 24 hours.
- pH – 10.5.
- Percent solids – 50% w/w.
Table 2-1 shows a summary of the variability recovery results.
|ILR||Leach on Midds
|Composite||g/t Au||% Au||% Au||% Au||g/t||g/t||g/t Au||% Au|
|* Overall gold dissolution refers to gold going into solution and does not include other losses incurred in the plant during operations|
Table 2-1: Variability Recovery Summary Results
The results indicate the following:
- Gravity gold recovery vary from 40.40% to 73.18% with an 85th percentile of 61.52%. These results indicate that the Kobada sulphide ore is amenable to gravity recovery.
- The 85th percentile overall gold dissolution is 93.87% which confirms initial findings that overall gold dissolution above 90% can be achieved on the sulphide ore. The ore leaches well to give tails of 0.03 g/t for low and high grades tested with the exception of North and South 4 samples. Low overall recoveries shown are consistent with low grades tested but tail grades are generally less than 0.03 g/t Au. This ties in with findings from the diagnostic leach test which indicated that 0.02 g/t of the gold is locked in quartz or gangue.
- Cyanide consumption values vary from 0.14 kg/t to 0.46 kg/t with an 85th percentile of 0.34 kg/t. These results confirm initial findings that the sulphide ore is a low cyanide consumer.
- Lime consumption values vary from 0.23 kg/t to 0.31 kg/t with an 85th percentile of 0.30 kg/t. These results indicate that the sulphide ore is a low lime consumer.
Definitive Feasibility Update
The Company is well underway to deliver an updated Definitive Feasibility Study in Q3-2021. The comprehensive update will target two key areas, namely inclusion of more than 7,000 m from the most recent drilling programme (see press release as of February 2, 2021) and inclusion of additional sulphides from the most recent metallurgical testwork into the resource and reserves.
Progress to date includes the following:
- Completion of a full suite metallurgical testwork on sulphide ore based upon multiple samples shipped from the site.
- Preparation and assay of more than 7,000 m of exploration drilling, predominantly focusing on Phase 4 infill drilling results (conversion of high grade inferred resources into measured and indicated category).
- Update of mineral resource and reserve estimates (in progress).
- Update of mine optimization, economic indicators, mine scheduling and waste dump designs based on revised life of mine plan.
- Comminution modelling based upon sulphide testwork.
- Process plant review and design update to treat oxides and sulphides, including but not limited to:
- Update of layouts, PFD’s and P&ID’s
- Update of Mechanical Equipment List (MEL)
- Update of single line diagrams and electrical loads
- Preparation of RFQ’s for additional equipment packages
- Update of SMPP designs and RFQs
- Full peer review and update on earthworks and civil engineering designs
- Tailings Storage Facility design update to incorporate additional volume based on envisaged higher tonnages, addition of sulphides and potential for higher throughput.
- Testwork on samples for TSF (testwork underway).
- Full CAPEX and OPEX update based upon updated SMPP and MEL and future timing of sulphide circuit as well as latest 2021 pricing.
- Updated economic model based upon updated economic indicators, consensus and latest production information.
- Receipt of multiple samples required for ESIA update, which includes but is not limited to:
- Decommissioning and closure plan
- Groundwater review
- Geotechnical testwork
- Air Quality and Noise Impact Assessment
- Blasting and Vibration assessment
- Biodiversity assessment
- Emergency Preparedness and Response plan
About African Gold Group
African Gold Group is a TSX Venture Exchange (TSX-V: AGG) listed exploration and development company with a focus on building Africa’s next mid-tier gold producer. The Company has a highly experienced board and management team with a proven track record in the African mining sector operating mines from development through to production. AGG’s principal asset is the Kobada Project in southern Mali, which is in an advanced stage of development having completed the 2020 definitive feasibility study and is targeting gold production of 100,000 oz per annum. As well as the initial Kobada Gold Project, other exploration locations have been identified on the Kobada, Farada and Kobada Est concessions, offering potential for an increase in resource. For more information regarding African Gold Group visit our website at www.africangoldgroup.com.
For more information:
President and Chief Executive Officer
+(27) 76 411 3803
Non-Executive Chairman of the Board
VP Corporate Development
Camarco (Financial PR)
+44 (0) 20 3757 4997
This press release contains “forward-looking information” within the meaning of applicable Canadian securities legislation. Forward-looking information includes, but is not limited to, statements regarding, processing of sulphide materials, appointment of officers and the grant of incentive stock options. Generally, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “expects” or “does not expect”, “is expected”, “budget”, “scheduled”, “estimates”, “forecasts”, “intends”, “anticipates” or “does not anticipate”, or “believes”, or variations of such words and phrases or statements that certain actions, events or results “may”, “could”, “would”, “might” or “will be taken”, “occur” or “be achieved”. Forward-looking information is subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of AGG to be materially different from those expressed or implied by such forward-looking information, including but not limited to: receipt of necessary approvals; general business, economic, competitive, political and social uncertainties; future prices of mineral prices; accidents, labour disputes and shortages and other risks of the mining industry. Although AGG has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking information. AGG does not undertake to update any forward-looking information, except in accordance with applicable securities laws.
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