Endeavour Silver Continues to Confirm High-Grade Structures During its 2024/2025 Drill Program at Pitarrilla

VANCOUVER, British Columbia, June 03, 2025 (GLOBE NEWSWIRE) — Endeavour Silver Corp. (“Endeavour” or the “Company”) (NYSE: EXK; TSX: EDR) is pleased to report positive drill results from its exploration program at its 100% owned Pitarrilla project in Durango, Mexico. The focus of the drill program is to further define the geometry of multiple, sub-vertical, mineralized feeder structures and the mineralized manto that was initially outlined by historical drilling. Drilling from surface and underground has been successful in intersecting high-grade silver, zinc and lead mineralization and provides additional confidence required to upgrade existing mineral resources.

Highlighted Drill Results from Casas Blancas Vein

• 1,127 gpt Ag, 1.40% Pb and 4.36% Zn for for 1,319 gpt AgEq over 2.08 m ETW, including 4,630 gpt Ag, 2.26% Pb and 3.49% Zn for for 4,814 gpt AgEq over 0.20 m ETW in hole BPD-505
• 893 gpt Ag, 2.06% Pb and 2.56% Zn for for 1,038 gpt AgEq over 3.97 m ETW, including 5,090 gpt Ag, 9.22% Pb and 0.84% Zn for for 5,363 gpt AgEq over 0.23 m ETW in hole BPD-506
• 232 gpt Ag, 1.05% Pb and 8.79% Zn for for 573 gpt AgEq over 4.10 m ETW, including 973 gpt Ag, 2.47% Pb and 33.94% Zn for for 2,246 gpt AgEq over 0.46 m ETW in hole BPD-501

Highlighted Drill Results from Danna Vein

• 2,481 gpt Ag, 2.39% Pb and 4.57% Zn for for 2,707 gpt AgEq over 1.03 m ETW, including 4,520 gpt Ag, 4.35% Pb and 7.96% Zn for for 4,918 gpt AgEq over 0.54 m ETW in hole BPU-005
• 307 gpt Ag, 2.11% Pb and 2.26% Zn for for 443 gpt AgEq over 5.22 m ETW, including 1,020 gpt Ag, 14.30% Pb and 14.25% Zn for for 1,904 gpt AgEq over 0.52 m ETW in hole BPU-014
• 322 gpt Ag, 1.57% Pb and 3.65% Zn for for 493 gpt AgEq over 7.37 m ETW, including 922 gpt Ag, 6.43% Pb and 12.55% Zn for for 1,538 gpt AgEq over 0.55 m ETW in hole BPU-019

Highlighted Drill Results from Victoria Vein

• 221 gpt Ag, 2.98% Pb and 6.39% Zn for for 527 gpt AgEq over 2.34 m ETW, including 495 gpt Ag, 6.91% Pb and 15.75% Zn for for 1,238 gpt AgEq over 0.30 m ETW in hole BPU-017
• 643 gpt Ag, 5.81% Pb and 6.93% Zn for for 1,043 gpt AgEq over 1.51 m ETW, including 1,015 gpt Ag, 9.15% Pb and 8.78% Zn for for 1,569 gpt AgEq over 0.91 m ETW in hole BPU-018

Highlighted Drill Results from Manto Pitarrilla

• 129 gpt Ag, 0.84% Pb and 2.55% Zn for for 242 gpt AgEq over 247 m, including 716 gpt Ag, 4.19% Pb and 6.61% Zn for for 1,062 gpt AgEq over 1.00 m and 2,680 gpt Ag, 24.03% Pb and 18.90% Zn for for 3,987 gpt AgEq over 0.60 m in hole BPU-022

Abbreviations include: gpt: grams per tonne; Ag: silver; Pb: lead; Zn: zinc; ETW: estimated true width; m: metre. Silver equivalents are calculated using prices of $26/oz for silver, $1.00/lb for lead and $1.35/lb for zinc. Variable amounts of gold and copper occur but have not been included in the AgEq calculation.

Drilling Context

The simplified geology of the Pitarrilla deposit includes three mineralized domains (Figure 5).

1. Upper volcanics, primarily of andesitic composition
2. Conglomerate (Manto Pitarrilla), flat lying, strata-bound with massive replacement mineralization
3. Lower marine sediments

In addition, at least four sulphide mineralized veins (Casas Blancas, Victoria, Danna, and Palmito) and two sulphide mineralized dykes (Cuchara and Pena) have been identified. Drilling has confirmed that all structures originate below the marine sediments, extend through Manto Pitarrilla, and into the upper volcanics. These feeder structures remain open at depth.

Between September 2024 and April 2025, an additional 31 drill holes totaling 11,200 metres have been completed. 4,360 metres from 12 holes collared from surface and 6,839 metres from 19 holes from underground drill stations. The Danna vein returned the widest mineralized interval with results up to 7.4 metres in estimated true width from hole BPU-019, while two of three holes that intersected Casas Blancas returned economic grades over 4.0 metres in estimated true width (BPD-501 and BPD-506).

Drill hole BPU-022 was drilled at a low angle (-22.5 degrees) through the horizontal lying Manto Pitarrilla and returned 247 m (apparent width) of 254 gpt AgEq (see figure 5). Due to the irregular geometry of the Manto Pitarrilla, true width is variable, however drill data estimates the dimensions to be approximately 400 metres wide and up to 100 metres high in some parts.

Table 1. Surface Diamond Drill Results

*Drill holes BPD-502, BPD-503, BPD-504, BPD-507, BPD-508, BPD-509, BPD-510, BPD-511 and BPD-512 returned no significant results

Table 2. Underground Diamond Drill Results, Vein Intercepts

Table 3. Manto Pitarrilla

(1) Note: No capping has been applied but high-grade intervals have been highlighted. True width has been calculated from interpreted sections. Gold (Au) and copper (Cu) have been excluded in the AgEq calculation.

Figure 1. Casas Blanca Longitudinal Section

Figure 2. Victoria Longitudinal Section

Figure 3. Danna Longitudinal Section

Figure 4. Palmito Longitudinal Section

Figure 5. Cross Section – Manto Pitarrilla

Since acquiring the Pitarrilla Project in July 2022, Endeavour has undertaken an extensive re-logging of historical drill core to enhance its understanding of the deposit’s geology and mineralization controls. The Company has prioritized the identification and delineation of multiple high-grade feeder structures, which are believed to be the primary conduits for the silver, lead, and zinc sulphide mineralization. These structures are interpreted to extend into the high-grade manto, initially outlined by the previous owner. A Technical Report supporting updated Mineral Resource Estimates was published on November 21, 2022 (refer to news release dated December 8, 2022).

Pitarrilla is a large undeveloped silver, lead, and zinc project located 160 kilometres north of Durango City, in northern Mexico. The project is within the Municipality of Santa María del Oro and Indé on the eastern flank of the Sierra Madre Occidental mountain range. The property comprises 4,752 hectares across five concessions and has significant infrastructure in place with direct access to utilities. A significant resource has been defined with over 240,000 metres of exploration drilling incurred to date. A number of key permits are already in place for underground mining and development, including permits for water use and discharge, general use of explosives, change use of soil, as well as underground mining and development which are permitted under an Environmental Impact Statement.

About Endeavour Silver

Endeavour is a mid-tier precious metals company with a strong commitment to sustainable and responsible mining practices. With operations in Mexico and Peru, and the development of the new cornerstone mine in Jalisco state, the company aims to contribute positively to the mining industry and the communities in which it operates. In addition, Endeavour has a portfolio of exploration projects in Mexico, Chile and the United States to facilitate its goal to become a premier senior silver producer.

Quality Assurance / Quality Control

Drill core samples were shipped to ALS Limited in Zacatecas, Mexico for sample preparation and then for analysis at the ALS laboratory in North Vancouver and rock samples were shipped to SGS Lab in Durango, Mexico for sample preparation and analysis. The ALS Zacatecas, North Vancouver facilities and SGS lab are ISO 9001 and/or ISO/IEC 17025 certified. Silver and base metals were analyzed using a four-acid digestion with an ICP-AES / ICP-OES finish and gold was assayed by 30-gram fire assay with atomic absorption (“AA”) spectroscopy finish. Over limit analyses for silver were re-assayed by 30-gram fire assay and gravimetric finish and for lead and zinc re-assayed using an ore-grade four-acid digestion with ICP-AES / ICP-OES finish.

Control samples comprising certified reference samples, duplicates and blank samples were systematically inserted into the sample stream and analyzed as part of the Company’s quality assurance / quality control protocol.

Qualified Person

Dale Mah, P.Geo., Vice President Corporate Development, a qualified person under NI 43-101, has approved the scientific and technical information contained in this news release.

Contact Information

Allison Pettit
Director, Investor Relations
Email: apettit@edrsilver.com
Website: www.edrsilver.com

Cautionary Note Regarding Forward-Looking Statements

This news release contains “forward-looking statements” within the meaning of the United States private securities litigation reform act of 1995 and “forward-looking information” within the meaning of applicable Canadian securities legislation. Such forward-looking statements and information herein include but are not limited to statements regarding the anticipated work program at Pitarrilla, areas of focus and priorities for the work program at Pitarrilla, a future economic study at Pitarrilla, Pitarrilla’s potential to create shareholder value, and the timing and results of various activities. The Company does not intend to and does not assume any obligation to update such forward-looking statements or information, other than as required by applicable law.

Forward-looking statements or information involve known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, production levels, performance or achievements of Endeavour and its operations to be materially different from those expressed or implied by such statements. Such factors include but are not limited to changes in production and costs guidance; the reliability of Mineral Resource Estimates; results of the work program at Pitarrilla; the ongoing effects of inflation and supply chain issues on mine economics; changes in national and local governments’ legislation, taxation, controls, regulations and political or economic developments in Canada and Mexico; financial risks due to precious metals prices; operating or technical difficulties in mineral exploration, development and mining activities; risks and hazards of mineral exploration, development and mining (including, but not limited to environmental hazards, industrial accidents, unusual or unexpected geological conditions, pressures, cave-ins and flooding); inadequate insurance, or inability to obtain insurance; availability of and costs associated with mining input and labour; the speculative nature of mineral exploration and development; risks in obtaining necessary licenses and permits; fluctuations in the prices of silver and gold; fluctuations in the currency markets (particularly the Peruvian sol, Mexican peso, Chilean peso, Canadian dollar and U.S. dollar); and challenges to the Company’s title to properties; as well as those factors described in the section “risk factors” contained in the Company’s most recent form 40F/Annual Information Form filed with the S.E.C. and Canadian securities regulatory authorities.

Forward-looking statements are based on assumptions management believes to be reasonable, including but not limited to: the continued operation of the Company’s mining operations, no material adverse change in the market price of commodities, the reliability of Mineral Resource Estimates; anticipated results of the work program at Pitarrilla, work programs will continue and will be completed in accordance with management’s expectations and achieve their stated outcomes, and such other assumptions and factors as set out herein. Although the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements or information, there may be other factors that cause results to be materially different from those anticipated, described, estimated, assessed or intended. There can be no assurance that any forward-looking statements or information will prove to be accurate as actual results and future events could differ materially from those anticipated in such statements or information. Accordingly, readers should not place undue reliance on forward-looking statements or information.

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