In Q4-2021, Endeavour’s Mana Gold Mine in Burkina Faso gold production increased due to higher processed grade and plant recovery rate, which was partially offset by a slight decrease in plant throughput.
Total open pit tonnes mined decreased due to reduced mining activity at the bottom section of Wona South Stage 2 pit which is nearing completion. This was partly offset by mining higher-grade ore from the Wona South Stage 3.
Total underground tonnes mined decreased due to increased waste and development mining activities at the Siou underground in order to increase the mining in stopes which delivered better grades. Total underground development metres slightly increased due to the commencement of development at the Wona underground mine, where two new portals were established.
Tonnes milled decreased due to a planned plant shutdown for mill relining while the average processed grade increased due to better grades mined at Wona South Stage 3 as well as Siou underground. Recovery rates increased slightly due to oxide materials from the Wona South Stage 3 pit.
AISC increased due to higher unit mining costs as a result of mining in deeper elevation of the Wona South stage 2 open pit, no more classification of open pit waste extraction as non-sustaining capital given the pit is nearing completion, and higher processing costs due to planned mill maintenance. This was partially offset by decreased sustaining capital expenditure due to less development at Siou underground.
Sustaining capital of $2.4 million, an increase compared to $2.1 million in Q3-2021, is related to underground development to create new stoping levels. Non-sustaining capital expenditure of $6.9 million, a decrease compared to $11.2 million incurred in Q3-2021, was mainly related to waste capitalisation, activities related to the preparation of the Wona underground portals and the TSF raise.
FY-2021 production totalled 205koz, significantly beating the guided 170-190koz range due to out-performance in mining of the Wona South open pit providing high grade feed to the processing plant and higher plant availability and capacity. This was partially offset by the lower grade. The AISC amounted to circa $1,026/oz achieving the guided $975-$1,050/oz range.
FY-2021 production increased by 83koz over the prior year due to the benefit of consolidating a full year of operations, strong plant performance and increased underground tonnes mined while the AISC increased by $173/oz primarily due to higher underground mining costs due to the mining of ore at increased depth, which was partially offset by lower open pit mining costs.
Following a strong out-performance in FY-2021, Mana is expected to produce between 170—190koz in FY-2022 at an AISC of $1,000—1,100/oz.
Mining at Wona open pit is expected to conclude at the end of H1-2022, while in H2-2022 mill feed is expected to be sourced primarily from Siou underground whilst development progresses at Wona underground where stope production is expected to commence in late FY-2022. Siou underground is largely developed and stope production is expected to be consistent throughout the year, though grade will vary depending on the stopes in production. Mining at the Maoula satellite pit, which was initially expected to commence in late H2-2022, is being considered to start earlier than planned. Mill throughout is expected to be lower in H2-2022 following the transition away from the Wona open pit. This is expected to be partially offset by supplemental feed from stockpiles and from Wona underground development in H2-2022 as well as slightly higher grades from Siou underground, while recovery rates are expected to remain strong.
Sustaining capital expenditure is expected to decrease from $12.6 million in FY-2021 to approximately $7.0 million in FY-2022, with expenditure relating mainly to plant maintenance and equipment re-builds. Non-sustaining capital expenditure is expected to be flat over FY-2021 at approximately $40.0 million in FY-2022, with expenditure relating mainly to the Wona underground development and associated infrastructure as well as Maoula infrastructure and a TSF wall raise.