This NI 43-101 technical report presents updated mineral resources and processing information for the Chirano Gold Mine in Ghana, effective 31 December 2023.
Report context
This technical report and updated Mineral Resource Estimate for Chirano Gold Mines Limited, which operates the Chirano Gold Mine in Ghana, West Africa, was prepared on behalf of Asante Gold Corporation. The effective date is 31 December 2023 and the issue date is 30 April 2024. The report is compliant with National Instrument 43-101 and Form 43-101F1. The Chirano Gold Mine has been in production since 2005 and has produced over 2.8Moz of gold since 2010 up to the end of 2023. Current life of mine is five years.
Processing route
Overall process description
The Chirano processing plant comprises a 3.6Mtpa milling and carbon-in-leach (CIL) processing circuit with associated infrastructure including tailings storage facilities. The plant processes ore from both open pit and underground operations.
Gravity circuit
A gravity concentration circuit was implemented in November 2023. The estimated gravity concentration recovery from 2023 test work is 10.5%. This resultant 10% reduction in the CIL head grade by gravity concentration mitigates recovery losses associated with coarse gold dissolution in the leaching circuit. The estimated overall gold recovery improvement from gravity concentration is in the range of 0.5% to 1.0%.
Intensive leach reactor
The plant includes an intensive leach reactor for processing gravity concentrate. Electrowinning is used for gold recovery from solution.
Current plant modifications
Modifications completed or planned include:
- Gravity circuit (installed November 2023)
- Pebble crusher
- Pressure Swing Adsorption (PSA) oxygen plant
- Shear reactor circuit (planned Q1 2024)
- Pre-leach and CIL agitators upgrade (planned Q2 2024)
- Mill cyclones upgrade (planned Q2 2024)
- Fine tertiary cone crusher (planned H1 2024)
Reagents
Reagents used in the processing plant include flocculant, Goldilox, hydrogen peroxide, caustic soda, and sodium cyanide.
Plant process services
Raw water and process water systems are in place, along with compressed air supply.
Plant gold recovery performance (2022-2023)
For the period August 2022 to September 2023, the plant processed an average of 285,289 tonnes per month in 2022 and 278,531 tonnes per month in 2023. Average feed grades were 1.34 g/t Au in 2022 and 1.47 g/t Au in 2023, with overall gold recoveries of 88% and 86% respectively.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Plant throughput capacity | 3.6 Mtpa | Design |
| Plant throughput (2022) | 3,423,470 tonnes | Actual operating data |
| Plant throughput (2023) | 3,296,882 tonnes | Actual operating data |
| Average feed grade (2022) | 1.34 g/t Au | Actual operating data |
| Average feed grade (2023) | 1.47 g/t Au | Actual operating data |
| Overall gold recovery (2022) | 88% | Actual operating data |
| Overall gold recovery (2023) | 86% | Actual operating data |
| Estimated gravity recovery | 10.5% | Testwork (2023) |
| Estimated overall recovery improvement from gravity | 0.5% – 1.0% | Estimated from testwork |
| Aboduabo oxide gold recovery (base case leach) | 87.8% – 93.5% | Testwork (Q4 2023) |
| Gold leached by direct cyanidation (tails sample) | 5.3% | Diagnostic leach test (2023) |
| Mild oxidative pre-leached gold extraction (tails sample) | 16.6% | Diagnostic leach test (2023) |
| Total gold recoverable from tails with shear reactor | 21.9% | Diagnostic leach test (2023) |
Project website: https://www.asantegold.com/operations/chirano
Technical qualifications
The qualified persons have not researched property title or mineral rights for the project and express no opinion as to the validity of ownership status of the property. The technical report has been prepared on the understanding that the current operations and property are, or will be lawfully accessible for evaluation, development, mining and processing. The qualified persons are independent of Asante Gold Corporation and there is no circumstance that could interfere with any judgments made in this technical report.
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Source: NI 43-101 Technical Report and Updated Mineral Resource Estimate, Chirano Gold Mines Limited, Ghana, West Africa, effective date 31 December 2023, issue date 30 April 2024.
