Mr. Don Gray reports

ENDEAVOUR SILVER PROVIDES A Q4 2024 CONSTRUCTION PROGRESS UPDATE ON TERRONERA; SURFACE CONSTRUCTION PROGRESS NEARLY 90% COMPLETE

Endeavour Silver Corp. has provided a Q4 2024 construction progress update for its Terronera project in Jalisco state, Mexico. A photo gallery presentation accompanies this news release and can be found on the company's website. All dollar references in this news release are in U.S. dollars.

Substantial progress was achieved on Terronera's upper plant platform during the fourth quarter, with systems commissioning under way. Focus continues on the lower platform.

"Endeavour Silver's Terronera project is nearing completion," commented Don Gray, chief operating officer. "Dry commissioning is advancing well on the upper platform and we're completing final installations and the last of the punch list items. Our team's efforts are concentrated on timely completion of the lower platform, where structural steel is advancing to install the tailing filters. We're focused on maintaining our construction schedule and momentum to have Terronera ready for full commissioning in early Q2 2025."

Q4 2024 construction and development highlights

Site works and activities as of Dec. 31, 2024:

• Safety: The health and safety program and procedures are complete and ready for transition from construction and commissioning into operations.
• Community relations: Community support and the hiring and training of local employees continue to be a priority.
• Progress: Overall project progress reached 89.4-per-cent completion. Current capital expenditures are approximately $302-million as of Dec. 31, 2024. Management estimates total project spend of $332-million.
• Mine development: During the fourth quarter, 1,694 metres were developed underground for a project total of 7,239 metres. Of note, the underground explosives magazine storage permit was approved, which will improve development efficiencies.
• Upper plant platform site: Much of the construction is complete, with final punch list items being addressed and various areas being handed over to the commissioning and operations teams:
  • Primary crusher: The primary jaw crusher commissioning was completed, and the area was transferred to operations. A total of 6,000 tonnes of ore has been crushed.
  • Grinding: Commissioning of the grinding circuit commenced with successful SAG (semi-autogenous) and ball mill testing for multiple hours at full operating speed to check bearing temperatures, vibrations and lubrication systems under no-load conditions.
  • Flotation: Flotation equipment, including pumps, tanks, verti-mill, low-pressure blowers and instrumentation have been installed. Remaining items for installation include pressure relief valves, hoses and final piping.
  • Raw and process water tanks: Installation and hydro testing are 100 per cent complete.
• Lower platform facilities and tailing storage facility (TSF): The lower platform area was 42 per cent complete:
  • TSF main embankment: The main embankment reached the 1,185-metre elevation and the TSF facility is ready to receive filtered tailings.
  • Tailing filters: Swing plates mounted below both tailing filters were installed and first-floor concrete was poured; structural steel installation is advancing for the second floor prior to installing the filter press.
  • Tailing area tanks: Storage tanks have been assembled; hydro testing and anchoring will be completed in Q1 2025.
  • Event pond liner: The pond area liner was installed; the feed and overflow channel lining will be completed in Q1 2025 (completed in January).
  • Upper surface water diversion canal: The TSF diversion canal for the south and east perimeters is nearly 90 per cent complete.
  • Concentrate filter building: The second concrete floor was poured and is ready for installing the concentrate filter.
• Auxiliary buildings:
  • Laboratory building: Construction was completed, and the facility was turned over to operations.
  • Plant maintenance building: The plant maintenance building reached 80-per-cent completion and is scheduled for completion in mid-Q1 2025.
• On-site personnel: At the end of Q4, the Terronera work force included 297 Endeavour Silver employees and 821 contract workers.

Updated initial capital cost

The project team conducted a comprehensive review of the remaining Terronera completion costs. The company forecasts initial capital costs to be $332-million (see table below). The mining cost increase of approximately $16-million is related to the extended project schedule as well as increased waste rock disposal costs, including hauling, placement at the temporary waste dump and construction of the permanent waste rock dump. Mineral process plant costs, which includes the lower platform and tailing facility construction, are estimated to be approximately $13-million over budget. These costs include additional work for expediting structural steel fabrication, blasting required for lower platform excavation, off-site materials purchased for tailing facility construction, extra work required for supporting the cut above the lower platform elevation and contractor indirect costs. The $2.2-million increase for site infrastructure is related to the additional scope for constructing the mill shop, warehouse and assay/met lab and temporary power generation. Total project indirect costs increased by $29-million, offset with the $8.7-million contingency. Owner costs increased due to additional engineering, construction management, enlarging the camp capacity and adding several administrative support buildings (for example, offices and training). Project indirect costs increased due to the extended project schedule and a larger work force, overlapping project construction and completion activities.

Next steps and planning

The Terronera project is anticipated to begin full system commissioning in early Q2 2025. For Q1 2025, upper platform efforts will focus on installing remaining items, punch list completion and commissioning. The TSF main embankment is anticipated to reach the final 1,198-metre elevation and tailing and concentrate filters will be installed, along with final piping, electrical and instrumentation work. The remaining critical path items are the tailing filter presses, which are expected to be completed by early Q2 2025. The company plans to provide operational guidance as construction approaches wet commissioning.

About Endeavour Silver Corp.

Endeavour is a mid-tier precious metal company committed to sustainable and responsible mining practices. With operations in Mexico 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, which has helped it achieve its goal of becoming a premier senior silver producer.

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