Centamin PLC announces Doropo pre-feasibility study update

Centamin (LSE:CEY)(TSX:CEE) is pleased to provide an update on the pre-feasibility study at its Doropo project located in north-eastern Cote d’Ivoire, including an upgrade to Mineral Resources; details of potential operating and capital cost-saving opportunities within the processing flowsheet; and identified resource growth potential within the license area.

Martin Horgan, CEO, commented: “The Doropo PFS workstreams are advancing well and delivering positive results. Following the completion of an extensive infill drilling programme through 2021 and 2022, we have now delivered the first mineral resource estimate constrained in pit shells, with 2.5Moz in the Indicated category eligible to be assessed for inclusion in the maiden reserves estimate. The Indicated Resource grade of 1.52g/t Au should support improved project economics given it exceeds the 1.25g/t Au average feed grade assumed in the 2021 PEA. In addition, the exploration team has successfully identified a number of targets for follow-up drilling that show potential to deliver further resource growth.

Furthermore as part of the PFS metallurgical test work programme, we have identified an opportunity to remove the flotation and regrind circuit that was outlined in the PEA, in favour of a whole of ore leach flowsheet. Given the potential to deliver significant capital and operating cost savings, we are undertaking further comparative test work ahead of publishing the outcome of the PFS which is now expected in H1 2023.”

Constrained mineral resource demonstrates the potential scale of eventual economic extraction

Over the last 18 months a 124,000 metre reverse circulation (“RC”) and core infill drilling programme was completed. PFS infill drilling was undertaken on a 25 metre x 50 metre spacing versus previously wider-spaced drilling of 50 metre x 50 metre. Samples were prepared on-site and sent to independent laboratories in Cote d’Ivoire and Ireland, with industry standard quality assurance and quality control (“QAQC”) applied.

The Mineral Resource Estimate (“MRE”) data presented in the tables included in this document comprises a summary extract of the Mineral Resource report for the Doropo project. For comparative purposes, data for 2021 has been included where possible. Note that the 2021 MRE is minimally constrained* and the 2022 MRE has been constrained using optimised pit shells.

Resource upside

Extensional and regional exploration targets identified

Over the last 18 months, in addition to the PFS infill drilling programme, the exploration team have focussed on surface mapping, geochemistry, portable x-ray fluorescence analysers (“pXRF”) multi-element analysis and reviews of the artisanal mining sites. Furthermore, historic data has been reinterpreted and reanalysed including the auger, RC, air-core and core drilling data, airborne geophysical data, and inductively coupled plasma (“ICP”) multi-element data.

Pre-feasibility update

Potential processing flowsheet update offers capital and cost saving opportunities

The 2021 PEA indicated a processing flowsheet which included a full flotation and regrind circuit. The results of the more detailed mineral processing and metallurgical recovery studies, including a more extensive metallurgical drilling programme, have indicated the potential to simplify the processing circuit.

The PFS mineral processing and metallurgical recovery studies included a dedicated 6,230 metre metallurgical drilling programme. The initial whole ore metallurgical test work was performed as a baseline for the detailed metallurgical test work programme. Gold extraction for the fresh samples averaged around 85% at an average head assay grade of only 0.6 g/t Au. With the oxide and transitional samples both averaging above 90% for assay head grades of 0.8 and 1.0 g/t Au respectively.

These encouraging initial results indicate the opportunity to remove the pyrite flotation, ultrafine grind circuit and subsequent flotation concentrate leaching circuits. This would have significant positive implications for both the capital and operating costs as the process flowsheet would become a more conventional whole of ore leach circuit configuration.

Centamin is now in the process of performing comparative testing of flotation and fine grinding configurations versus whole of ore leaching to confirm the potential to remove the PEA flotation circuit flowsheet design.

Given the material impact this could have on the overall economics of the project we have taken the decision to delay the results of the PFS into H1 2023 when we expect the comparative study to be completed.


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