Calibre Expands Trench Intercept at the 100% Owned Montes de Oro Target to 52.3 Metres Grading 7.1 g/t Gold

VANCOUVER, BRITISH COLUMBIA--(Marketwired - Aug 15, 2013) - Calibre Mining Corp. (TSX VENTURE:CXB) (the "Company" or "Calibre") is pleased to provide an update on activities at the 100% owned Montes de Oro target within the Siuna District, Borosi Concessions, northeast Nicaragua.

Highlights

• Results from extensions of Trench MTR13-009 have expanded the high grade mineralized intercept to 52.3 m grading 7.1 g/t Au.

• Additional high grade trench results returned from recent work include; 23.0 m grading 5.25 g/t Au (MTR13-017) including 9.0 m grading 10.15 g/t Au, 16.2 m grading 4.68 g/t Au (MTR13-019) including 6.0 m grading 10.14 g/t Au.

• At Montes de Oro, trenching has partially tested a strong coincident gold-silver-copper-lead-zinc soil anomaly extending over a 400 metre by 650 metre area which remains open to the northeast.

President and CEO, Greg Smith stated, "Calibre continues to advance the Montes de Oro target, intersecting high grade gold mineralization over expanding widths. This high priority target continues to return consistently high grade gold intercepts with recent work now showing apparent widths of several tens of metres. On-going work is advancing the understanding of the mineralization."

Recent trench results include;

- Weighted averages calculated using uncut assays.

- Trench intercepts are sample lengths and further work is required to determine true widths.

- For previous Montes de Oro trench results see Calibre news releases dated June 3 and July 26, 2013.

Based on the latest assays results at least two high grade sub-parallel mineralized trends are present at Montes de Oro (MTR13-009 trend and MTR13-017 trend). The zones have an inferred northeast orientation and appear to dip shallowly to the northwest. The MTR13-009 trend may continue as far as MTR13-018 a distance of approximately 200 metres.

Six new trenches and three trench extensions were completed at Montes de Oro during July 2013 for a total of 208.4 metres. The MTR13-017 tunnel extension returned a composite of 23.0 m grading 5.25 g/t Au and remains open to the northwest. The gold mineralization in MTR13-017 is distributed throughout the tunnel, primarily associated with a strongly oxidized horizon which dips between 20-40 degrees to the northwest roughly concordant with bedding. The mineralized oxide zone present in MTR13R-024 is very similar to the zone present in MTR13-017 and may be an "up dip" extension of the horizon located along strike to the west-southwest. MTR13-024 returned 3.70 m grading 3.86 g/t Au.

Other significant results are from trenches MTR13-022 with 6.0 m grading 4.73 g/t Au and MTR13-025 with 3.5 m grading 5.51 g/t Au, 0.11% Cu and 0.32% Zn. Both MTR13-022 and MTR13-025 contained lenses of massive sulphide with mineralization similar to MTR13-009. The mineralization present in trenches MTR13R-007, MTR13-018 and MTR13R-020 is similar in style and is primarily hosted within a strongly oxidized, argillic altered and fractured equigranular diorite unit. No obvious quartz veining has been observed but the rock is strongly fractured and contains rafts of sulphide bearing sediments. A northeast oriented zone of higher grade mineralization can be traced over a length of 50 m between trenches MTR13-020 and MTR13-018. Lower grade disseminated style mineralization also exists with long intervals including 39.40 m grading 0.96 g/t Au in MTR13-018 and 50 m grading 0.53 g/t Au in MTR13-020.

In addition to the regional host volcano-sedimentary package at least two phases of intrusive rocks have been mapped on the property; the principal hornblende bearing equigranular diorite and a coarse hornblende diorite unit.

The existing soil anomaly at Montes de Oro is a strong coincident gold-silver-copper-lead-zinc anomaly which extends over a 400 metre by 650 metre area and remains open to the northeast. Two additional soil lines were added to the Montes de Oro soil grid to test the northeast extension and a total of 22 samples were collected. The results are pending.

Work continues at Montes de Oro, targeted at further defining the high grade gold mineralization and testing the extensions of existing trenches and additional anomalous areas. Updated maps detailing the result of the current exploration programs will be posted on the Company's web site at www.calibremining.com.

Quality assurance and quality control procedures include the systematic insertion of blanks, standards and duplicates into the rock sample strings. Samples are placed in sealed bags and shipped directly to Acme Labs in Managua, Nicaragua for sample preparation and then to Acme Labs in Vancouver, Canada for gold fire assay and ICP multi element analyses. The technical content in this news release was read and approved by Gregory Smith, P.Geo, President and CEO of the Company who is the Qualified Person as defined by NI 43-101.

About Calibre Mining Corp.

Calibre controls a 100% interest in 429 km² of mineral concessions and additionally, Calibre has joint venture exploration programs underway with B2Gold Corp. on 322.3 km ² of concessions which include the Primavera gold-copper porphyry discovery and Alder Resources Ltd. on the 33.6 km² Rosita gold-copper-silver project. Major shareholders of Calibre include gold producer B2Gold and investment fund Sun Valley Gold.

Calibre Mining Corp.

Greg Smith, P.Geo., President and CEO

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.