Mr. Ryan King of Calibre reports

CALIBRE AND IAMGOLD SIGN OPTION AGREEMENT ON THE EASTERN BOROSI PROJECT, NICARAGUA

Calibre Mining Corp. and Iamgold Corp. have signed an option agreement, dated May 26, 2014, whereby Iamgold can earn a 51-per-cent interest, and subsequently an additional 19-per-cent interest, for a total of 70-per-cent interest in the Eastern Borosi project, consisting of 176 square kilometres within the Borosi concessions in northeast Nicaragua. The Eastern Borosi project hosts gold-silver resources in two deposits and a series of well-defined low-sulphidation epithermal gold-silver targets. Unless otherwise specified, all amounts set out in this news release are expressed in U.S. dollars.

Highlights:

• First option: To earn a 51-per-cent interest in the Eastern Borosi project, Iamgold must pay Calibre $450,000 and invest $5-million in exploration on the property over three years.
• The minimum year-one exploration commitment under the first option is $1.5-million.
• Second option: Once vested at 51 per cent, Iamgold can elect to earn an additional 19 per cent in the Eastern Borosi project for a total of 70 per cent by paying Calibre an additional $450,000 and by investing a further $5-million in exploration on the project over a subsequent three-year term.
• The total potential investment by Iamgold under the first and second options is $10.9-million.

President and chief executive officer Greg Smith stated: "Calibre is tremendously excited to have formed this partnership with Iamgold to advance the gold-silver resource potential of the Eastern Borosi project. The Eastern Borosi project represents less than 40 per cent of Calibre's 463 square kilometres of 100-per-cent-owned concessions in the mining triangle of Nicaragua. On the Eastern Borosi project, Calibre has defined existing gold-silver resources at the Riscos de Oro and La Luna deposits, and has also outlined a series of high-priority drill targets, all with existing permits, allowing for drill testing of new, high-grade vein targets and for expanding the existing gold-silver resource base. We welcome Iamgold to Nicaragua, where they join B2Gold Corp. and Alder Resources Ltd. as Calibre's partners in advancing the gold-silver-copper potential of the Borosi concessions. Calibre and our shareholders will benefit from our three partners investing a total of up to $12-million on the company's gold-silver-copper projects over the next three years."

Significant terms of the Calibre-Iamgold option agreement

1. First option: Iamgold has the option to earn a 51-per-cent interest in the mineral titles held by Calibre in the Eastern Borosi project of the Borosi concessions. The option consists of:
   1. Iamgold to invest $5-million in exploration on the project over three years;
   2. There will be a minimum $1.5-million year-one commitment, and additional expenditures are optional;
   3. Iamgold will make cash payments to Calibre totalling $450,000, including $150,000 on signing, $150,000 on the first anniversary date and $150,000 on the second anniversary date of the option agreement;
   4. Iamgold will present exploration budgets and plans to a technical committee, having equal representation from Iamgold and Calibre, for approval with Iamgold to have tie-breaking vote;
   5. Calibre to be project operator in the first year, or a longer period should the parties agree, with Iamgold having the option to assign a geologist;
   6. Iamgold to have the right to take over operatorship following the first anniversary, or such later time as the parties agree;
   7. During the period that Calibre operates, it will receive a 10-per-cent overhead recovery fee on all costs incurred on the project, except government payments and drill contracts for which the overhead fee will be 5 per cent;
2. Second option: Iamgold to earn an additional 19 per cent over the subsequent three years by spending an additional $5-million and making staged cash payments of an additional $450,000 in three annual payments;
3. At such time as Iamgold exercises the second option, or elects not to enter into the second option, the parties will form a joint venture to advance the project; the participation ratio of Iamgold to Calibre interests will be 51:49 or 70:30, depending on whether the second option has been exercised;
   1. At such time, the parties will agree to enter into an industry-standard agreement to govern a joint venture when formed;
   2. Should a party elect not to participate in a work program, a standard straight-line dilution formula will apply;
   3. Dilution to a 10-per-cent direct joint venture interest converts to a 10-per-cent net profits interest (NPI);
4. The option agreement with Iamgold is subject to TSX Venture Exchange approval.

Iamgold and Calibre are in agreement on the objectives for the initial $1.5-million 2014 exploration program on the Eastern Borosi project, and diamond drilling is expected to commence in the near term. Previous work by Calibre has outlined a series of high-priority drill targets, including the existing Riscos de Oro and La Luna gold-silver deposits, the high-grade Guapinol and Blag gold systems, as well as the La Sorpresa and El Paraiso gold targets. The Riscos de Oro and La Luna National Instrument 43-101 inferred mineral resources are shown in the attached table and are open for potential expansion.

           EASTERN EPITHERMAL PROJECT INFERRED RESOURCE 
                 SUMMARY -- BOROSI PROJECT, NICARAGUA                                 
                                                                            

Zone               Tonnes  Grade  Grade  Grade  Contained  Contained  Contained
                             (Au    (Ag  (AuEq         Au         Ag       AuEq   
                             g/t)   g/t)   g/t)   (ounces)   (ounces)   (ounces) 

La Luna         2,539,000   1.56  14.01   1.78    127,700  1,143,570    146,000 
Riscos de Oro   2,159,000   3.20  59.67   4.14    222,300  4,142,000    287,000 
Total                                            350,000   5,286,000    433,000 

1. Resource models used inverse-distance grade estimation within a three-   
   dimensional block model with mineralized zones defined by wireframed     
   solids and a base cut-off grade of 0.6 gram per tonne.
2. The resource estimate for Riscos de Oro is detailed in a technical report      
   titled "NI 43-101 Technical Report and Resource Estimation of the Riscos 
   de Oro Deposit, Borosi Concessions, Nicaragua" by Todd McCracken, dated   
   Oct. 9, 2012.                                                         
3. The resource estimate for La Luna is detailed in technical report titled
  "NI 43-101 Technical Report and Resource Estimation of the Cerro 
   Aeropuerto and La Luna Deposits, Borosi Concessions, Nicaragua" by Todd 
   McCracken, dated April 11, 2011.
4. A density of 2.65 grams per cubic centimetres was applied. For Riscos 
   de Oro, a capping of silver grades at 591 grams per tonne was applied.                                           
5. Numbers may not add exactly due to rounding.                             
6. Gold equivalent (AuEq) for Riscos de Oro was calculated using prices of 
   $1,264 per ounce gold and $19.78 per ounce silver, and for La Luna, AuEq
   was calculated using prices of $1,058 per ounce gold and $16.75 per 
   ounce silver, and metallurgical recoveries and net smelter returns are 
   assumed to be 100 per cent.               
7. Mineral resources that are not mineral reserves do not have economic     
   viability.
8. The quantity and grade of reported inferred resources in this estimation 
   are uncertain in nature, and there has been insufficient exploration to   
   define these inferred resources as an indicated or measured mineral      
   resource, and it is uncertain if further exploration will result in       
   upgrading them to an indicated or measured mineral resource category.    

Calibre's 100-per-cent-owned concessions

Calibre maintains 100-per-cent ownership of the 253-square-kilometre Siuna district, which hosts the Cerro Aeropuerto mineral resource consisting of an NI 43-101 inferred mineral resource at a 0.6-gram-per-tonne-gold-equivalent cut-off of six million tonnes, grading 3.64 grams per tonne gold and 16.16 grams per tonne silver, containing 707,750 ounces gold and 3.1 million ounces silver (see Calibre news release dated Feb. 28, 2011). Cerro Aeropuerto is one kilometre south of the now Calibre-owned historic La Luz mine, which produced 2,273,000 ounces of gold from 17 million tonnes grading 4.14 grams per tonne gold from skarn-style mineralization. Additionally, at the Montes de Oro target, located 10 kilometres north of the La Luz mine, Calibre has outlined a 400-metre-by-650-metre gold-in-soil anomaly with trenching results to date, including 52.3 metres grading 7.1 grams per tonne gold, 27.5 metres grading 4.92 grams per tonne gold and 19.3 metres grading 2.71 grams per tonne gold (see Calibre news release dated Jan. 23, 2014, and Nov. 20, 2013, for further details). At Montes de Oro, gold-skarn target trenching has defined two high-grade, subparallel gold mineralized zones: one 250 metres long and one 500 metres long.

Calibre-B2Gold option/joint venture

Calibre and B2Gold have a joint venture that gives B2Gold the right to acquire an additional 19-per-cent interest (70 per cent total) in the Primavera gold-copper project and surrounding Borosi concessions by spending $6-million (Canadian) on exploration over three years. At the Primavera gold-copper project, past drilling intersected significant porphyry-style mineralization, including 261.7 metres grading 0.78 gram per tonne gold and 0.3 per cent copper. Additional channel sampling in 2013 returned high-grade results from the Minnesota gold project, including 9.2 metres grading 4.17 grams per tonne gold. An exploration program managed by B2Gold continues on a series of targets, with recent trench results from the Minnesota gold project including 14.8 metres grading 1.85 grams per tonne gold and 8.5 metres grading 1.22 grams per tonne gold.

Calibre-Alder Resources option

Calibre's third agreement in the Borosi concessions has granted Alder Resources an option to earn a 65-per-cent interest in the 33.6-square-kilometre Rosita gold-copper-silver project by spending $4-million (Canadian) on exploration and by issuing to Calibre a total of one million Alder common shares by 2015. Past production from the Santa Rita open-pit gold-copper-silver mine was 305 million pounds of copper, 177,737 ounces of gold and 2.6 million ounces of silver. Significant drill intercepts from Alder's work include 65 metres grading 1.48 grams per tonne gold, 0.2 per cent copper and two grams per tonne silver, and 15 metres grading 15.82 grams per tonne gold, 0.04 per cent copper and 0.23 gram per tonne silver. Alder has tabled an NI 43-101 inferred mineral resource in gold-copper-silver surface stockpiles at a 0.15-per-cent-copper-equivalent cut-off of 7.9 million tonnes, grading 0.46 gram per tonne gold, 0.62 per cent copper and 9.2 grams per tonne silver, containing 118,000 ounces gold, 108 million pounds copper and 2.35 million ounces silver (see Calibre news release dated May 9, 2012).

The technical content in this news release was read and approved by Gregory Smith, PGeo, president and chief executive officer of the company, who is the qualified person as defined by NI 43-101.