Endeavour Mining Increases Ity Project Mineral Resources to 3.8 Million Ounces of Gold

Abidjan, July 27, 2017 - Endeavour Mining (TSX:EDV) (OTCQX:EDVMF) is pleased to announce that its exploration program at its Ity CIL Project, in Cote d'Ivoire, has increased the Indicated Resource by 1.0 million ounces since the beginning of the year, to reach 3.8 million ounces.

As illustrated in Table 1, this marks a 1.5 million ounce increase in the Indicated Resource base since the publication of the November 2016 Feasibility Study ("FS"), representing a 65% increase. An updated reserve estimate is expected to be published in September as part of an Optimization Study ("OS") which is expected to be based on a circa 4.0Mtpa gravity circuit/Carbon-In-Leach ("CIL") plant, an increase from the previously contemplated 3.0Mtpa plant, to better capture the value created from recent exploration success.

Table 1: Summarized Resource Evolution Following Publication of 2016 CIL Feasibility Study

Reserves shown exclude the Heap Leach operation Reserves. Resource estimated to the Indicated status, as such no Measured Resources available. Mineral Reserve estimates follow the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") definitions standards for mineral resources and reserves and have been completed in accordance with the Standards of Disclosure for Mineral Projects as defined by National Instrument 43-101. Notes for the 2017 Optimization Study Inventory Mineral Resource estimate are provided in Section "About the Mineral Resources" of this Press Release, with effective date May 31, 2017. Full details on the Year-End 2016 Inventory and the 2016 Feasibility Study Inventory are available in the Company's published press releases dated respectively March 7, 2017 and November 10, 2016.

Patrick Bouisset, Executive Vice-President Exploration and Growth at Endeavour, said: "Our exploration team has done exceptional work over the past months which has led to a significant increase in the resource base at Ity ahead of the Optimization Study. These results and the numerous other identified targets, on which initial drilling reconnaissance is currently being conducted, further demonstrate the prospective nature of the greater Ity area and our confidence in delivering against our 5-year exploration strategy disclosed last November. We believe that the 80km Ity corridor which we control is among the most prospective areas in West Africa and we look forward to building on our exploration success."

Sébastien de Montessus, President & CEO, stated: "Under Patrick's leadership, Ity has been transformed from a 20-year operation nearing the end of its life into an asset that now has the potential to be one of our flagship operations. Our ability to quickly grow the Indicated Resource demonstrates the robustness of Ity, as well as the quality of our exploration team. We now look forward to announcing the results of the Optimisation Study and making a formal investment decision in September, following which we will transition the construction team from Houndé to Ity later this year."

EXPLORATION EFFORTS

Ahead of the Optimization Study, exploration efforts since the beginning of the year have been mainly directed at increasing Indicated Resources on known deposits through in-fill, delineation, and extension drilling, with up to eight rigs deployed. As shown in Figure 1 below, more than 31,000 meters of diamond drilling were conducted, with efforts mainly focused on Daapleu, Bakatouo, Verse Ouest, Colline Sud and Mont Ity/Ity Flat deposits.

In parallel, initial drilling also took place on several other exploration targets in the vicinity of the Ity mine and the Le Plaque discovery, which was announced earlier this year. This exploration program will be pursued during the second half of 2017, following the integration of pending analysis results.

Figure 1: Ity Mining Complex H1-2017 Exploration Drilling Focus

Compared to the resource inventory used to build the 2016 Feasibility Study, a total of 1.5Moz of Indicated Resources were added, with the main increases coming from the discovery of Bakatouo (+704koz), and additional Indicated resources outlined at Daapleu (+384koz), Mont Ity / Flat (+189koz), and Verse Ouest (+187koz), as shown Table 2 below.

Table 2: Resource Evolution Following Publication of 2016 CIL Feasibility Study

Resource estimated to the Indicated status, as such no Measured Resources available. Mineral Reserve estimates follow the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") definitions standards for mineral resources and reserves and have been completed in accordance with the Standards of Disclosure for Mineral Projects as defined by National Instrument 43-101. Notes for the 2017 Optimization Study Inventory Mineral Resource estimate are provided in Section "About the Mineral Resources" of this Press Release, with effective date April 30, 2017. Full details on the Year-End 2016 Inventory and the 2016 Feasibility Study Inventory are available in the Company's published press releases dated respectively March 7, 2017 and November 10, 2016.

BAKATOUO DEPOSIT

A total of 4,700 meters comprising 30 holes were drilled on the Bakatouo deposit following the publication of its maiden resource in late 2016, with both infill and extension drilling done as shown in Figure 2 below.

Figure 2: Bakatouo Drill Area

Drilling conducted during the first half of 2017 has identified additional mineralization within the previous resource envelope and at depth, as well as through some extensions which remain partially open to the southeast, southwest, northwest and northeast of the deposit.  Additional drilling is planned in the second half of the year to test these extensions, with the priority being the northeast extension.

Figure 3: Bakatouo Cross-Section

As shown in the table below, the H1-2017 program added 229koz of Indicated Resources while the average grade decreased as ounces added through the defined extensions were of lower grade than the central part of the deposit. The Indicated resource however remains very robust with more than 35% of its Indicated Resource grading above 4.5 g/t and 50% grading above 3.0 g/t. Due to its higher-grade nature, the Optimization Study envisages Bakatouo to be mined in the first years of the CIL production.

Table 3: Bakatouo Resource Evolution

DAAPLEU DEPOSIT

A total of over 14,860 meters, comprising 77 holes, were drilled on the Daapleu deposit consisting of both infill drilling and resource delineation outside of and as an extension of the down dip of the 2016 resource boundary, as illustrated in Figure 4 below, increasing the Daapleu Indicated Resource by 384koz to 1,349koz.

Figure 4: Daapleu Drill Area

The H1-2017 program has demonstrated the high continuity of mineralization (Fluidized Rhyolite and high grade shear zone) within the Daapleu deposit, which remains fully open at depth towards the northwest as illustrated in Figure 5 below.

Figure 5: Daapleu Cross-Section

MONT ITY/ITY FLAT DEPOSIT

A total of over 8,300 meters, comprising 77 holes, were drilled at the Mont Ity /Ity Flat deposits during the first half of 2017, concentrating on the northeast high grade zone which was not previously accessible for drilling due to ongoing mining activities. This drill campaign confirmed the continuity of mineralization between the two areas, which are now considered to be a single deposit, and added 189koz of Indicated Resources. An additional drilling program is ongoing on the central part of the Mont Ity deposit in order to convert additional Inferred Resources into Indicated status before year-end.

The results demonstrate the very high grade mineralization in this area of the deposit, as shown in selected intercepts illustrated in Figure 6 below.

Figure 6: Mont Drill Area

Within the drilled area, mineralization remains clearly open at depth, as shown in Figure 7 below.

Figure 7: Mont Ity/Flat Cross-Section

OTHER NEARBY TARGETS

In H1-2017, initial exploration drilling, for which the results are still pending, also took place on several other exploration targets in the vicinity of the Ity mine (as per the blue dashed area in the Figure 8 below) and on the Le Plaque discovery which was announced earlier this year. This area, located within 5km from the current Ity mining complex, represents a small portion of the 80km corridor controlled by Endeavour.

This exploration program will be pursued in Q4-2017, after the end of the rainy season and the integration of pending analysis results, with the main focus on delineating a maiden Inferred Resource at the Le Plaque discovery.

Figure 8: Ity Mine Area and Surrounding Exploration Targets

NEXT STEPS

• Follow-up drilling on the Bakatouo extensions
• Drilling campaign on Le Plaque to delineate the extent of mineralized potential and aim for Inferred status by year-end
• Follow-up drilling on other exploration targets in the vicinity of the Ity mining complex
• Follow-up on the airborne geophysical survey, soil geochemistry, and auger drill results obtained in H1-2017 on the Greater Ity regional area

QUALIFIED PERSONS

The scientific and technical content of this news release has been reviewed, verified and compiled by Gérard de Hert, EurGeol, Senior VP West Africa Exploration for Endeavour Mining. Gérard de Hert has more than 19 years of mineral exploration and mining experience, and is a "Qualified Person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101"). 

ASSAYS AND QUALITY ASSURANCE/QUALITY CONTROL

All the related drill samples were prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects. All samples were diamond drill core (HQ and NQ size at Daapleu and Bakatouo, HQ and NTW at Ity-Ity FLat). After photography, and geologic and geotechnical logging, the core was marked up for sampling via approved procedures and was cut in half with electric saw and diamond impregnated core blades. Sampling involved collecting the left-hand side at designated sampling intervals for processing and analysis, and leaving the right-hand side in core boxes for reference.

Samples were dried, crushed and pulverized on site at the SMI Ity exploration mechanical preparation facilities. The facilities were constructed and commissioned with Bureau Veritas Laboratories (Abidjan), an independent laboratory services provider, whom also designed and implemented site procedures and protocols and supervised training. In January 2017, SGS Laboratories (SGS Cote D'Ivoire SA) took over the management and running of the preparation facilities, as part of a new contract with SGS to build and run an onsite laboratory to process present and future exploration and mine sample processing requirements. The new laboratory maintains separate dedicated preparation equipment for both exploration and mine samples.

The pulverized samples (pulps) were stored in 200g kraft paper packets and shipped to SGS Burkina SA in Ouagadougou for gold analysis. Samples were analyzed using a standard 50-gram gold fire assay with an Atomic Absorption finish (FAA505); above detection limit samples were re-analyzed via gravimetric procedure (FAG505).

Sampling and assay data were monitored through a quality assurance/quality control program designed to follow NI 43-101 and industry best practice. Certified reference materials were sourced from Geostats Pty Ltd Australia. Standards (oxide and sulphide at different grades) duplicate and blank control samples were inserted at a rate of 18 in every batch of 100 samples submitted to SGS. Results are loaded electronically into the company's Acquire database.

ABOUT THE MINERAL RESOURCE  

The insitu Mineral Resources, which include Daapleu, Mont Ity / Ity Flat, Bakatouo, Gbeitouo, Walter, Zia NE and Colline Sud, have been reported inside optimised pit shells and above a 0.5 g/t Au cut-off. Reporting within an optimised pit shell satisfies the requirement for the Mineral Resource to have reasonable prospects for future economic extraction. The pit optimisation assumes a US$1,500/oz Au price.

The Mineral Resource for the rock dumps, which include the Teckraie and Verse Ouest Mineral Resources and also the Aires heap leach pad, have not been reported inside an optimised pit shell. These deposits have been built up above the existing topography and the associated shallow laterite located directly below, therefore satisfying the requirement for the Mineral Resource to have reasonable prospects for future economic extraction. The Teckraie and Verse Ouest rock dump Mineral Resources and Aires leach pad Mineral Resources have been reported above 0.0 g/t Au because there is unlikely to be any grade selectivity during mining. The underlying laterite Mineral Resources for each of the deposits has been reported above 0.5 g/t Au given the possibility for some mining selectivity. All Mineral Resources are current as at April 30, 2017. Mineral resources which are not mineral reserves do not have demonstrated economic viability.

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.

The statistical analysis, geological modelling and resource estimation for Colline Sud were prepared by Kevin Harris, CPG. Mr. Harris is Endeavour Mining's Group Resource Manager and is a "Qualified Person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101").

The statistical analysis, geological modelling and resource estimation for Bakatouo, Mt Ity/Ity flat, Daapleu and Verse Ouest were prepared by Mark Zammit, CPG. Mr. Zammit is a principal consultant geologist with Cube Consulting Pty Ltd and is a "Qualified Person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101").