Endeavour Silver Intersects High-Grade Silver-Lead-Zinc Mineralization at its Kolpa Operation

Rhea-AI Summary

Endeavour Silver (NYSE: EXK) has announced significant drill results from its ongoing exploration program at the Kolpa Mine in Peru. The company intersected high-grade mineralization, including notable results of 247 gpt Ag, 0.77% Pb, 10.70% Zn and 0.55% Cu over 8.20 metres in hole DDH-H1-25-88, and 266 gpt Ag, 1.34% Pb, 4.73% Zn and 0.23% Cu over 5.15 metres in hole DDH-H1-25-92.

The exploration focused on the Poderosa West and Caudalosa Chica veins within Corridor 3. The Poderosa West vein has been mapped at surface for approximately 2.5 kilometers, with 14 drill holes completed totaling 2,343 meters. The company plans to resume drilling in late Q4 2025 and is developing new underground drill stations for further step-out drilling.

Positive

• None.

Negative

• Exploration results are still preliminary with no defined resource estimates yet
• Some drill holes returned limited or no significant mineralization

Insights

Mining Exploration Geologist

Encouraging high-grade silver-polymetallic drill results at Kolpa strengthen resource potential and demonstrate exploration upside.

Endeavour Silver's exploration drilling at its Kolpa operation in Peru has yielded impressive high-grade intersections that significantly enhance the project's resource potential. The standout results include 247 gpt silver with 10.70% zinc over 8.20 meters and 266 gpt silver with 4.73% zinc over 5.15 meters of true width. These grades are substantially above typical economic thresholds for underground mining operations.

The geological context is particularly promising - the identified structural corridors with 'structural pairing' create ideal conditions for mineralization. The Poderosa West vein's 2.5-kilometer surface exposure represents significant exploration potential, with only 14 drill holes completed so far. Similarly, the Caudalosa Chica vein extends for over 1.5 kilometers and has barely been tested with just three initial holes.

What makes these results compelling is their location within an established mining district with existing infrastructure. The planned systematic exploration program, including both underground and surface drilling, indicates a methodical approach to resource development. The polymetallic nature of the mineralization (silver, lead, zinc, copper) provides valuable co-product credits that enhance overall economics, effectively lowering the silver equivalent cost of production.

This exploration success demonstrates that Endeavour has barely scratched the surface at Kolpa, with multiple underexplored structural corridors suggesting substantial resource growth potential. The company's planned resumption of drilling in Q4 2025 should provide a steady flow of exploration results that could significantly expand the project's resource base.

VANCOUVER, British Columbia, Sept. 25, 2025 (GLOBE NEWSWIRE) -- Endeavour Silver Corp. (“Endeavour” or the “Company”) (TSX: EDR, NYSE: EXK) is pleased to announce positive drill results from its ongoing exploration program at the Kolpa Mine, located in Peru’s Huancavelica province. The area is marked by sub-vertical geological structures formed by compressive forces associated with the Andean Orogeny. These forces have created well-developed vein systems trending southwest to northeast, which are significant for guiding mineralization.

Importantly, these structural patterns can repeat and extend across neighboring vein sets that are oriented differently. This creates adjoining sequences—referred to as ‘structural pairing’—that enhance the potential for mineral discovery. The Company has successfully identified corridors where these structural pairings occur, targeting prospective areas for brownfields exploration.

Within Corridor 3, the Company carried out drilling on the Poderosa West and Caudalosa Chica veins, targeting the establishment of mineral resources. The Poderosa West vein, previously identified through both surface outcrops and earlier drilling, has now been mapped at surface for approximately 2.5 kilometers. Since acquiring the project, Endeavour has completed 14 drill holes totaling 2,343 meters near existing underground workings, intersecting significant zones of mineralization. Key highlights from this program include:

• 247 gpt Ag, 0.77% Pb, 10.70% Zn and 0.55% Cu over 8.20 metres estimated true width in hole DDH-H1-25-88
  
  
• 266 gpt Ag, 1.34% Pb, 4.73% Zn and 0.23% Cu over 5.15 metres estimated true width in hole DDH-H1-25-92
  
  

Additionally, Caudalosa Chica has been mapped for over 1.5 kilometers where three drill holes were completed in July and August, two intersected significant mineralization.

Management is currently evaluating both surface exploration and recent drill results to design a comprehensive, systematic exploration program at the Kolpa Mine. At Poderosa West, ongoing underground development is facilitating access for new underground drill stations, which will support further step-out drilling. Additionally, the Company has submitted applications for surface drilling along the entire 2.5-kilometer vein. Drilling activity in Corridor 3, targeting these two key structures, is scheduled to resume in late Q4 2025.

“Kolpa’s geology continues to demonstrate outstanding potential, with multiple underexplored targets that point to a long runway of discovery,” said Dan Dickson, Chief Executive Officer. “We are only scratching the surface and the opportunity to unlock further value through exploration is both exciting and significant. The latest results highlight the exploration potential for Kolpa and the hard work that the team has put into this asset.”

Table 1. Significant Drill Results

Hole	Structure	From (m)	To (m)	True Width (m)	Ag (gpt)	Pb	Zn	Cu
						(%)	(%)	(%)
DDH-H1-25-106	Ramal (HW Caudalosa 1)	66.1	68.3	2.2	107	1.10	1.43	0.19
	Caudalosa 1	109.65	112.05	2.4	0.93	0.01	0.03	0.00
DDH-H1-25-109	Caudalosa 1	117.85	120.1	1.7	33	0.25	0.28	0.03
	Ramal (FW Caudalosa 1)	158.85	159.15	0.3	313	8.16	30.00	0.18
DDH-H1-25-74	Poderosa West	388.55	389.15	0.6	95	4.02	2.74	0.72
DDH-H1-25-76	Poderosa West	136.65	137.95	1	45	0.92	2.49	0.15
DDH-H1-25-80	Poderosa West	142.15	143.85	1.3	35	2.68	2.96	0.09
DDH-H1-25-83	Poderosa West	166.9	168.15	1	9	0.16	0.68	0.07
DDH-H1-25-88	Poderosa West	37.55	45.75	8.2	247	0.77	10.70	0.55
DDH-H1-25-92	Poderosa West	53.05	58.2	5.15	266	1.34	4.73	0.23

Abbreviations include: gpt: grams per tonne; Au: gold; Ag: silver; m: metre.

Note: An additional six holes were drilled including holes DDH-H1-25-70, 71, 72 and 73 intercepted the Poderosa West vein and were assayed internally and not supervised by a Qualified Person. DDH-H1-25-90 was abandoned and DDH-H1-25-102 targeted a separate vein that returned no significant results.

Figure 1. Structural Corridors

Table 2. Drill Hole Locations and Orientation

Hole	East	North	Elevation	Azimuth	Dip	Area
DDH-H1-25-70	500117.57	8556436.51	4514.60	215.5	25.1	Poderosa West
DDH-H1-25-71	500117.08	8556435.59	4513.30	199.9	-33.7	Poderosa West
DDH-H1-25-72	500117.26	8556435.53	4513.00	146.9	-37.4	Poderosa West
DDH-H1-25-73	500116.78	8556435.80	4513.50	112.6	-30.0	Poderosa West
DDH-H1-25-74	499706.85	8556574.35	4756.80	188.1	-14.9	Poderosa West
DDH-H1-25-76	500152.27	8556317.94	4515.06	10.6	-57.2	Poderosa West
DDH-H1-25-80	500147.64	8556316.60	4514.32	293.7	-52.8	Poderosa West
DDH-H1-25-83	500152.51	8556318.81	4514.88	45.0	-40.0	Poderosa West
DDH-H1-25-88	500226.92	8556466.85	4513.14	165.0	-42.0	Poderosa West
DDH-H1-25-90	499707.51	8556574.15	4756.90	170.0	-12.0	Poderosa West
DDH-H1-25-92	500227.66	8556467.22	4513.32	120.0	-35.0	Poderosa West
DDH-H1-25-102	499707.02	8556583.04	4755.74	359.7	-38.8	Silvia-Vanessa
DDH-H1-25-106	502253.65	8555492.11	4393.05	348.6	-23.0	Caudalosa
DDH-H1-25-109	502253.64	8555492.26	4394.91	9.5	16.5	Caudalosa

Kolpa is a silver-focused polymetallic mine in the districts of Huachocolpa and Santa Ana in the province and department of Huancavelica, approximately 490 km southeast of Lima, Peru. The Company directly or indirectly holds mining rights to 143 mining concessions and claims covering 25,177 hectares and 1 beneficiation concession covering 366 hectares. Mineralization at Kolpa occurs mainly as polymetallic epithermal deposits rich in silver, lead, zinc and copper.

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.

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.

Drill core samples, with the exception of DDH-H1-25-106 and DDH-H1-25-102, were shipped to Certimin Laboratory, located in Lima, Peru, for sample preparation and analysis. The Certimin lab is ISO/IEC 17025, ISO 9001, 14001 and 45001 certified. Silver and base metals were analyzed using a multi-acid digestion with four acids with an ICP-OES finish and gold was assayed by 30-gram fire assay, read by atomic absorption spectroscopy (AAS). Over limit analyses for silver were re-assayed by 30-gram fire assay and gravimetric finish and for lead, zinc and copper re-assayed by ore-volumetric assay.

Drill core samples for drill holes DDH-H1-25-106 and DDH-H1-25-102 were sent to the Bureau Veritas Laboratory in Lima, Peru, for sample preparation and analysis. This laboratory holds international certifications such as ISO/IEC 17025, ISO 9001, ISO 14001, ISO 45001, and ISO 22000, which guarantee the quality of its processes. Silver and base metals were analyzed using a multi-acid digestion with four acids with an ICP-OES finish and gold was assayed by 30-gram fire assay, with atomic absorption spectroscopy (AAS) reading. Over limit analyses for silver were re-assayed by 30-gram fire assay and gravimetric finish and for lead, zinc and copper re-assayed using volumetric methods.

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.

Contact Information

Allison Pettit
Vice President, Investor Relations
Tel: (604) 685 - 9775
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 Company’s exploration and drilling plans and programs at Kolpa, exploration potential at Kolpa, Kolpa’s potential to create shareholder value, the opportunity for mineral discovery 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 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 Peru, 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; 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, mining operations will operate and the mining products will be completed in accordance with management’s expectations and achieve their stated production 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.

A photo accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/ba2f1d9e-5689-457f-8876-d87a1d5a5e5c

FAQ

What were the key silver grades discovered in Endeavour Silver's (EXK) Kolpa Mine exploration?

The exploration revealed high-grade results including 247 gpt Ag over 8.20 metres in hole DDH-H1-25-88 and 266 gpt Ag over 5.15 metres in hole DDH-H1-25-92.

Where is Endeavour Silver's Kolpa Mine located and what is its size?

The Kolpa Mine is located in Peru's Huancavelica province, approximately 490 km southeast of Lima. The property comprises 143 mining concessions covering 25,177 hectares and 1 beneficiation concession covering 366 hectares.

What is the extent of the Poderosa West vein at EXK's Kolpa Mine?

The Poderosa West vein has been mapped at surface for approximately 2.5 kilometers and has been confirmed through both surface outcrops and drilling.

When will Endeavour Silver resume drilling at the Kolpa Mine?

Endeavour Silver plans to resume drilling activities in Corridor 3, targeting the Poderosa West and Caudalosa Chica veins, in late Q4 2025.

What type of mineralization is present at EXK's Kolpa Mine?

Kolpa contains polymetallic epithermal deposits rich in silver, lead, zinc and copper, with mineralization occurring in sub-vertical geological structures.