Mr. Darren Hall reports

CALIBRE INTERCEPTS HIGH-GRADE GOLD & SILVER MINERALIZATION FROM SEVERAL TARGETS AT ITS EASTERN BOROSI MINE COMPLEX; DRILLING INTERSECTS INCLUDE 10.81 G/T GOLD OVER 3.4 METRES, 9.64 G/T GOLD OVER 3.3 METRES, 1,431.6 G/T SILVER OVER 2.9 METRES AND 642.3 G/T SILVER OVER 5.0 METRES

Calibre Mining Corp. has released drill results from its 2023 resource conversion and expansion program within its 176-square-kilometre Eastern Borosi mine complex located in northeastern Nicaragua, adjacent to a larger, 100-per-cent-owned, prolific 7,281 square km Atlantic mineral concession package.

Gold highlights from the Eastern Borosi drill program:

• 6.87 grams per tonne (g/t) gold (Au) over seven metres estimated true width (ETW), including 19.80 g/t Au over 1.1 metres ETW and 6.08 g/t Au over 3.8 metres ETW, in hole BL-23-118;
• 5.72 g/t Au over 8.9 metres ETW, including 8.21 g/t Au over 4.8 metres ETW and 7.50 g/t Au over 1.3 metres ETW, in hole BL-23-131;
• 8.46 g/t Au over 5.8 metres ETW, including 14.80 g/t Au over 2.9 metres ETW, in hole BL-23-133;
• 7.06 g/t Au over 17.7 metres ETW, including 14.70 g/t Au over 3.3 metres ETW, 12.69 g/t Au over 3.4 metres ETW and 8.92 g/t Au over 2.3 metres ETW, in hole BL-23-136;
• 10.81 g/t Au over 3.4 metres ETW, including 19.10 g/t Au over 1.8 metres ETW, in hole BL-23-143;
• 9.64 g/t Au over 3.3 metres ETW in hole BL-16-044;
• 5.77 g/t Au over 14.5 metres ETW, including 14 g/t Au over 3.8 metres ETW and 10 g/t Au over 2.2 metres ETW, in hole GTH-BL-23-006.

Silver highlights from the Eastern Borosi drill program:

• 1,431.6 g/t silver (Ag) over 2.9 metres ETW, including 1,240.5 g/t Ag over 1.4 metres ETW, in hole BL-15-018;
• 642.3 g/t Ag over five metres ETW, including 1,014 g/t Ag over two metres ETW, in hole BL-15-017;
• 401.8 g/t Ag over 3.5 metres ETW, including 925 g/t Ag over 1.3 metres ETW, in hole BL-23-111;
• 318.1 g/t Ag over 1.5 metres ETW in hole BL-23-112;
• 307.3 g/t Ag over 2.7 metres ETW in hole BL-23-115;
• 227 g/t Ag over nine metres ETW, including 247.8 g/t Ag over 4.8 metres ETW and 437 g/t Ag over 1.3 metres ETW, in hole BL-23-131;
• 181.9 g/t Ag over 2.8 metres ETW, including 288.5 g/t Ag over 1.7 metres ETW and 162.6 g/t Ag over 5.8 metres ETW, including 225.2 g/t Ag over 2.9 metres ETW, in hole BL-23-133.

Note: Estimated true widths for reported vein intercepts are based on 3-D models of individual veins. Estimates are determined in cross-section by measuring the modelled vein thickness perpendicular to the vein margins and through the midpoint of the drill hole intercept. Percentage-based differences between individual ETWs and downhole interval lengths will vary between drill holes depending on drill hole inclination, variations in vein strike and dip, and overall geometries of the different vein systems.

Darren Hall, president and chief executive officer of Calibre, stated: "These drill results at Eastern Borosi reinforce the potential for discovery and resource expansion within the 176 square km Eastern Borosi land package. Moreover, the exceptionally high silver grades demonstrate further potential to capture additional value in the future. During the second quarter of 2023, Calibre achieved a significant milestone as we commenced mining from our high-grade Guapinol open pit (see news release dated April 18, 2023). Today's high-grade results, combined with the established mineral resource base at Eastern Borosi and the potential for mine life extension at our Guapinol operation, confirm the significant mineral endowment of the district. In addition, the 7,281 square km Atlantic mineral concessions are at an early stage but have high-potential for the discovery of both epithermal gold-silver and porphyry copper-gold mineral systems."

Quality assurance/quality control (QA/QC)

Calibre maintains a QA/QC program for all its exploration projects using industry best practices. Key elements of the QA/QC program include verifiable chain of custody for samples, regular insertion of certified reference standards and blanks, and duplicate check assays. Drill core is halved and shipped in sealed bags to Bureau Veritas in Managua, Nicaragua, an independent analytical services provider with global certifications for quality management systems (ISO 9001:2008), environmental management (ISO 14001) and safety management (OH SAS 18001 and AS4801). Prior to analysis, samples are prepared at Veritas's Managua facility and then shipped to its analytical facilities in Vancouver, Canada. Gold analyses are routinely performed by fire assay/AA finish methods. For greater precision of high-grade material, samples assaying 10 grams per tonne gold or higher are reassayed by fire assay with gravimetric finish. Analyses for silver and other elements of interest are performed by induction coupled plasma (ICP).

Qualified person

The scientific and technical information contained in this news release was approved by David Schonfeldt, PGeo, Calibre Mining's corporate chief geologist and a qualified person under National Instrument 43-101.

About Calibre Mining Corp.

Calibre is a Canadian-listed, Americas focused, growing mid-tier gold producer with a strong pipeline of development and exploration opportunities across Newfoundland and Labrador in Canada; Nevada and Washington in the United States; and Nicaragua. Calibre is focused on delivering sustainable value for shareholders, local communities and all stakeholders through responsible operations and a disciplined approach to growth. With a strong balance sheet, a proven management team, strong operating cash flow, accretive development projects and district-scale exploration opportunities, Calibre will unlock significant value.

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