ENDEAVOUR TO LAUNCH EXPANSION OF SABODALA-MASSAWA;
DFS CONFIRMS ITS POTENTIAL TO BECOME TOP TIER GOLD MINE

London, 4 April, 2022 Endeavour Mining plc (LSE:EDV, TSX:EDV, OTCQX:EDVMF) ("Endeavour" or the "Group" or the "Company") is pleased to announce that it will soon launch the construction of its Sabodala-Massawa expansion in Senegal, supported by the recently completed Definitive-Feasibility Study (“DFS”).

The DFS recommends the expansion of the Sabodala-Massawa complex by supplementing the current 4.2Mtpa Carbon-in-leach (“CIL”) plant with a 1.2Mtpa BIOX® plant to process the high-grade refractory ores from the Massawa Central Zone and Massawa North Zone deposits (“Expansion Project”), with first gold production expected in early 2024.

Sébastien de Montessus, President and CEO of Endeavour Mining, said : “We are extremely pleased with both the current performance of Sabodala-Massawa and the Definitive Feasibility Study results announced today, as they demonstrate the asset’s potential to be a top tier mine capable of producing in excess of 400,000 ounces per year at an industry-leading AISC.

Given the robust project economics, which significantly exceed our investment criteria, and the strong exploration upside potential, we are excited to launch this low-capex intensive brownfield expansion project as it will continue to improve the quality of our operating portfolio and contribute to driving the Group’s return on capital employed above our 20% target. In line with our capital allocation framework, we are very pleased to be able to pursue this organic growth opportunity while maintaining a healthy balance sheet and the financial flexibility to continue to deliver strong capital returns to shareholders.

We believe we are well positioned to unlock the full value of the Sabodala-Massawa complex as we have significantly de-risked the project by integrating key changes into the DFS, based on experience gained from operating the asset and the results of further technical analysis, and we have highly experienced operating and construction teams already in place.”

As shown in Tables 1 and 2 below, the Expansion Project is expected to yield an incremental production of 1.35Moz of gold at a low AISC of $576/oz over the life of mine and boasts robust economics with an after-tax IRR of 72%, NPV _5% of $861 million and a quick 1.4-year payback period at a gold price of $1,700/oz.

Table 1: Sabodala-Massawa Expansion Project Highlights (excludes current CIL operation)

Table 2: Sabodala-Massawa Expansion Project Economics (excludes current CIL operation)

As shown in Figure 1 below, the Expansion Project is expected to add an incremental average production of 194koz per year, over its first five years of operations (2024 – 2028) at an average AISC of $531/oz. As such, the Expansion Project is expected to lift the Sabodala-Massawa complex to top tier status with an expected average annual production of 373koz per year over the next 5 years at an average AISC of $745/oz for the combined CIL and BIOX® operation, as shown in Table 3 below.

Strong upside potential exists as the DFS does not include the conversion of the previously announced discovery of 709koz of M&I resources, which is expected to notably boost 2023 production.

Figure 1: Production Profile (next 10 years) for Sabodala-Massawa Combined CIL and BIOX® Operation

Table 3: Sabodala-Massawa Combined CIL and BIOX® Operation Summary

As shown in Table 4 below, the mine is capable of self-funding the Expansion Project given the robust cumulative cash flow expected to be generated from the existing CIL operation in 2022 and 2023.

Table 4: Sabodala-Massawa Combined CIL and BIOX® Operation – Next 5 years profile

Leveraging Endeavour’s construction and operating experience, several key changes have been incorporated in the DFS, compared to Teranga’s 2020 PFS, to significantly de-risk the project, as summarized in Table 5 below.

Table 5: Key Changes in DFS vs. PFS

DEFINITIVE-FEASIBILITY STUDY DETAILS

Background
Endeavour acquired the Sabodala-Massawa mine from Teranga Gold on 10 February 2021, prior to which Teranga Gold acquired the Massawa project from Barrick Gold on 4 March 2020, combining the Sabodala mill and deposits with the nearby Massawa deposits. As such, the Sabodala-Massawa mine consists of two mining licenses, the Sabodala exploitation permit (“Sabodala licence”) and the Massawa exploitation permit (“Massawa licence”) and two further exploration permits. The Sabodala licence is held by Sabodala Gold Operations SA (“SGO”) while the Massawa license is held by Massawa SA (“Massawa”). Endeavour holds indirectly through its subsidiaries a 90 percent stake in each of SGO and Massawa with the Government of Senegal holding the remaining interest.

In August 2020, Teranga Gold filed a Preliminary Feasibility Study (“PFS”) for the phased expansion of Sabodala-Massawa. In 2021, Endeavour expedited the completion of the initial upgrades at the existing Sabodala-Massawa CIL plant and simultaneously advanced the DFS for the addition of a refractory ore processing plant to confirm the economic viability of processing the high-grade refractory ores from the Massawa Central Zone and Massawa North Zone deposits.

Lycopodium Minerals Pty Ltd (“Lycopodium”) was responsible for the compilation of the report and delivery of the DFS to Endeavour. Orelogy completed the mine design for the DFS. Minescope Services are consulting on the Process Plant, while Metso-Outotec, who own the BIOX® technology, are providing the BIOX® and milling technology. Land and Marine Geological Services Pty Ltd (“L&MGSPL”) will be designing and executing the Tailings Storage Facility (“TSF”) design. QGE Pty Ltd (“QGE”) will be providing the power station expansion engineering services and managing the delivery of the power station expansion by an Original Equipment Manufacturer on a lump sum turn key basis.

Endeavour expects to file a Technical Report pursuant to National Instrument 43-101 – Standards of Disclosure for Mineral Projects in respect of the Sabodala-Massawa DFS within the following 45-day period.

Geology
At the Sabodala-Massawa Complex, all of the defined mineral resources are within the Sabodala and Massawa exploitation permit areas. The permit areas are transected by two prominent, first order shear zones, the Main Transcurrent Shear Zone (“MTZ”) and the Sabodala-Sofia Zone (“SSZ”) both trending north-northeast. Existing deposits and exploration targets are closely associated with these first order structures.

Figure 2: Sabodala-Massawa Geology Map

Within the Sabodala licence, lithologies generally trend north-northeast to northeast with steep dips. The sequence is dominated by mafic volcanics, with intercalated interflow sediment horizons.

On the Massawa licence, the stratigraphy is dominated by a package of volcaniclastic rocks to the west, and a package of greywackes to the east. Bedding typically strikes to the north-northeast with a steep dip of between 75° to 80° toward the west. Several igneous rocks including sills of gabbro, felsic intrusions, and feldspar (and/or quartz-feldspar) porphyries intrude this dominantly clastic sequence.

The deposits at the Sabodala-Massawa Complex are classified as orogenic gold deposits. The mineralisation is often associated with quartz shear veins, extension vein arrays, shear zones, and disseminated sulphides. Mineralisation is typically associated with greenschist metamorphic grade and vein dominated styles. The typical mineralogy of the gold-bearing mineralisation is quartz-carbonate ± albite ± K-feldspar veins with up to 10% (pyrite ± arsenopyrite ± base metals) sulphides. Alteration assemblages are typically dominated by iron-rich carbonate, albite, chlorite, scheelite, fuchsite and tourmaline. High grades are more commonly associated with high strain environments, and with the presence of arsenopyrite. The continuity of the gold grade is associated with alteration style, deformation intensity, and the presence of intrusive contacts. Gold is often hosted in brecciated zones, along with extensional and shear veins. Typically, moderate to strong silica-carbonate alteration and sulphides are present.

Reserves and Resources
As shown in Table 6 below, the mineral reserves and resources for the Sabodala-Massawa complex (Combined CIL and BIOX® operation) stand at 4.44Moz and 6.88Moz respectively. The current resource to reserve conversion ratio is temporarily low, at 65%, as the previously announced discovery of 709koz of M&I resources are yet to be reflected in Reserves.

Table 6: Sabodala-Massawa (Combined CIL and BIOX® Operation) Mineral Reserves and Resources

The mineral Reserves and Resources were estimated as at 31 December 2021 in accordance with the provisions adopted by the Canadian Institute of Mining Metallurgy and Petroleum (CIM) and incorporated into the NI 43-101. Reported tonnage and grade figures have been rounded from raw estimates to reflect the relative accuracy of the estimate. Minor variations may occur during the addition of rounded numbers. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Resources were constrained by MII Pit Shell and based on an open-pit cut-off of grade range of 0.50 g/t Au to 1.00 g/t Au and an Underground cut-off grade range of 2.00g/t Au to 2.84 g/t Au. Reserves are based on a gold price of $1,300/oz and resources are based on a gold price of $1,500/oz.

The DFS economics for the Expansion Project is based on the refractory ore reserves, which represent 35% of the mine’s reserves, as detailed in Table 7