Calibre Mining Corp. provided an update on the company's exploration activities and recent discoveries at the 100% owned Riscos de Oro gold-silver deposit and other high priority targets in the Eastern Epithermal District on the Borosi Concessions, northeast Nicaragua. Calibre controls a 100% interest in 429 km(2) of mineral concessions in the Mining Triangle of NE Nicaragua. Additionally, Calibre has joint venture exploration programs underway with Alder Resources Ltd. on the 33.6 km(2) Rosita gold-copper-silver project; and with B2Gold Corp. on 322.3 km(2) of concessions which includes the Primavera gold-copper porphyry discovery. New Discoveries; Calibre continues to outline numerous high priority targets along two sub-parallel gold-silver vein trends; the 8.5 kilometre Riscos de Oro - El Paraiso Trend and the >10km Guapinol - La Sorpresa Trend; significant trench results have been returned for BTR13-097 on the Riscos de Oro vein extension located 500 m north-east of the existing gold-silver resource; 2 veins intersected: 13.50 m @ 3.26 g/t Au and 14.7 g/t Ag (0.00-13.50m), including 3.00m @ 11.51 g/t Au and 56.6 g/t Ag (6.60-9.60m). Additional soil results returned from the Guapinol-California area; evidence for numerous parallel vein sets with cumulative strike length of 15.8 km; numerous rock samples containing anomalous Au-Ag values, Mapping and prospecting in the La Sorpresa area identified up to 5 vein systems with a cumulative strike length of 5.8 km; rock sampling returned up to 42.46 g/t Au and 2457 g/t Ag. The vein-style gold-silver mineralization discovered in Calibre's Eastern Epithermal District is geologically similar to mineralization at the near-by Bonanza mine which has produced in excess of 2.8 million ozs of gold. Calibre continues to advance the Riscos de Oro - El Paraiso trend. Work has included; 9427.6 m diamond drilling (37 holes), 232 surface rock samples, 382 trench rock samples, 587.7 m trenching (26 trenches), 63.4 line km soil sampling (2,432 samples), as well as reconnaissance geologic mapping over 36 km(2). Significant results include; multiple significant drill intersections by Calibre including 10.25 g/t Au and 288.25 g/t Ag over 5.40 m in RD11-010; the Riscos de Oro gold-silver deposit has been confirmed over a 725 m strike length and to a depth of 300 m and remains open for resource expansion; gold in soil anomaly has been delineated over a 7 kilometre strike length from the deposit towards the southwest. Additional work is planned including; trenching of best soil and rock geochemical anomalies and follow-up diamond drilling program testing the along strike extension of the system. Results have been received for a step out trench completed on the Riscos de Oro trend 500 metres northeast of the existing resource area. The trench returned 13.50 m grading 3.26 g/t Au and 14.7 g/t Ag (including 3.00m @ 11.51 g/t Au and 56.6 g/t Ag) from two epithermal quartz veins. The results from this trench extend the Riscos de Oro structure 500 metres towards the northeast. Calibre continues to define the recently identified Guapinol - La Sorpresa gold-silver trend. Work completed includes; 199 surface rock samples, 41 line km soil sampling (2,055 samples), and reconnaissance geologic mapping over 27 km(2). Work to date has outlined multiple parallel, northeast oriented gold and silver bearing quartz vein systems. Surface rock results include 42.5 g/t Au, 2457 g/t Ag, 4468 ppm Pb and 1513 ppm Zn highlighting the high-grade nature of some veins. Long lived, small scale artisanal mining in the Guapinol and California areas confirms consistent gold grades in quartz veins. Planned work includes trenching of high priority soil and rock geochemical anomalies. Historic drilling at the Guapinol gold-silver zone consisted of 16 diamond drill holes testing a single structure along 150 metres of strike length and down to a depth of approximately 80 vertical metres. Drilling highlights include: G-4; 1.84 m @ 2.33 g/t Au and 276.48 g/t Ag, G-6; 1.52 m @ 28.87 g/t Au and 21.87 g/t Ag, G-8; 3.10 m @ 13.08 g/t Au and 10.02 g/t Ag, and G-11; 0.5 m @ 32.43 g/t Au and 103.15 g/t Ag. Mapping, prospecting and soil sampling completed in 2013 along the Guapinol-La Sorpresa trend successfully identified up to 7 parallel veins in the immediate Guapinol prospect area while five new vein systems have been identified in the area of the La Sorpresa prospect. Other veins have been identified in the El Carmen and Pueblo Santo areas. Recent soil and rock results have further defined and extended the multiple parallel epithermal veins encountered in the Guapinol trend to a cumulative strike length of over 15.8 km. The majority of the veins occur within three main northeast oriented parallel systems.

Calibre Mining Corp. (TSXV:CXB) has retained Roman Friedrich and Company Limited to provide financial advice regarding strategic alternatives available to Calibre Mining to enhance its shareholder value. Calibre Executive Chairman Douglas Forster stated, "I have worked with RFC in the past and look forward to this relationship adding significant value to Calibre and our projects in Nicaragua. Calibre's current 1.0 million oz. Inferred Gold Resource is open for resource expansion and with $2.3 million in working capital and new gold/silver discoveries at Guapinol, La Sorpresa, Montes de Oro and La Virgen in addition to the Primavera gold-copper discovery Calibre is well positioned to enhance shareholder value in the historic and underexplored Mining Triangle of north-east Nicaragua."

Calibre Mining Corp. announced that the Company has signed a letter agreement with B2Gold Corp. granting B2Gold an option to acquire a further 19% interest in and to the Primavera Gold-Copper Porphyry Project containing a total of 322 km(2) of mineral concessions in north-east Nicaragua. Calibre currently controls a 49% interest in the Project, while B2Gold controls a 51% interest and is project operator. In addition to this joint venture with B2Gold, Calibre controls a 100% interest in 463 km(2) of mineral concessions in the Mining Triangle of northeast Nicaragua. This Letter Agreement dated April 24, 2013 confirms the agreement between Calibre and B2Gold to enter into a definitive Joint Venture Agreement ("JV Agreement") with respect to the Project, which will contain a further option for B2Gold to earn an additional 19% interest in and to the Project for a total interest of 70% by spending $6.0 million in additional project expenditures over 3 years. Upon entering into the JV Agreement, the original Option Agreement between Calibre and B2Gold (entered into in June 2009 and amended in July 2010 and October 2010) will terminate and be superseded by the JV Agreement.