VANCOUVER, BRITISH COLUMBIA -- (MARKET WIRE) -- 09/27/12

Calibre Mining Corp. (TSX VENTURE:CXB) (the "Company" or "Calibre") is pleased to provide an update on the exploration programs directed at the Company's 100% owned projects on the Borosi Concessions, northeast Nicaragua. Calibre controls a 100% interest in 511.1 km2 of prospective gold, silver and copper mineral concessions in northeast Nicaragua that include the Cerro Aeropuerto, La Luna and Riscos de Oro gold-silver deposits that host a combined NI 43-101 Inferred Resource at a 0.6 g/t AuEq cut-off of 10,750,000 tonnes grading 3.06 g/t Au and 24.38 g/t Ag containing 1,057,000 oz Au, 8,430,000 oz Ag (see Calibre news release dated September 5, 2012). Additionally, Calibre has joint venture exploration programs underway with Alder Resources Ltd. on the 33.6 km2 Rosita gold-copper-silver project and B2Gold Corp. on the 322.3 km2 Primavera gold-copper porphyry project and surrounding exploration concessions.

Calibre exploration programs have been on-going throughout 2012 on both the:

1.  100% owned Eastern Epithermal Gold-Silver District which includes the
    Riscos de Oro and La Luna gold-silver deposits as well as the Blag Gold
    Project; and 

2.  100% owned Western Siuna Gold-Silver District which includes the past
    producing La Luz gold mine, Cerro Aeropuerto gold deposit and extensive
    underexplored exploration targets. 

President and CEO, Greg Smith, states; "In addition to increasing Calibre's 100% owned NI 43-101 Inferred Resources on the Borosi Concessions to over 1.0 million oz Gold and 8.4 million oz Silver our geologists and field crews continue to be highly successful in discovering and expanding the mineralized footprint within this highly prolific yet underexplored gold-silver-copper district. We continue to advance our 100% owned projects through cost efficient exploration targeted at the discovery and delineation of porphyry, skarn and epithermal gold-copper-silver mineralization."

Eastern Epithermal Gold-Silver District is in the north-eastern portion of the Borosi Concessions and contains the Riscos de Oro and La Luna gold deposits as well as the Blag Gold Project. Highlights of recent advancement include:

1.  Completion of the initial National Instrument 43-101 Inferred Resource
    Estimate at Riscos de Oro at a cut off grade of 0.6 g/t AuEq of
    2,159,000 tonnes grading 3.20 g/t Au and 59.67 g/t Ag (4.14 g/t AuEq)
    containing 222,300 oz Au and 4,142,000 oz Ag (287,100 oz AuEq.) - see
    news release September 5, 2012; 

2.  Completion of a 90 km2LiDAR laser topographic mapping survey covering
    the Riscos de Oro, La Luna and Blag areas which was highly successful in
    defining numerous previously unrecognized structural zones; 

3.  Follow-up detailed soil and rock sampling has been completed on
    structural targets; and 

4.  Trenching of high priority structural targets is on-going. 

LiDAR surveys were completed over the Eastern Epithermal District with the production of high resolution topographic data and imagery. The surveys identified interpreted epithermal vein systems and targets in areas of poor relief and/or thick vegetative cover along strike from known zones and in areas previously unidentified.

At Blag more than 25 individual structures were recognized the longest of which is greater than 1.5 kilometres in length. Based on results of the LiDAR a detailed program of soil sampling was completed along lines spaced at roughly 100 metre intervals. A total of 881 samples were analysed with values ranging up to 1040 ppb Au and 21 samples returning highly anomalous values greater than 100 ppb Au. In conjunction with the soil sampling a program of mapping, prospecting, and rock sampling was also undertaken. Grab samples of epithermal-style quartz vein material on surface highlighted several areas with highly anomalous contents for gold and silver. Anomalous gold values are associated with variably anomalous values in silver, arsenic, barium, lead, and antimony. Highlights of the rock sample results include:

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SampleID  Easting  Northing  Au g/t  Ag g/t  As_ppm  Ba_ppm  Pb_ppm  Sb_ppm
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B12R5036 800068.3 1555278.5   22.72    12.3      72     151      44       1
B12R1031 802067.1 1555585.4   13.50   100.0      20      32     623      84
B12R0068 800076.4 1555282.0   11.29     9.7     121     107      30       1
B12R5059 800093.4 1555315.2    6.90     4.8      50     447      10       6
B12R5061 799753.0 1555167.6    3.80     5.8      27      55       1       6
B12R1054 800512.2 1555238.6    3.02     1.9      15      50      27       2
B12R5056 801183.1 1556391.4    2.98   231.7       5      37     162       3
B12R5062 801567.5 1556070.3    2.73   423.9      22     119     140       7
B12R3006 800516.2 1555234.5    2.52     1.2      16      30      15       1
B12R1028 802088.0 1555280.9    2.34    74.6     2.5     102      10      11
B12R1056 800517.8 1555235.7    1.25     2.7      17      88      19       7
B12R1035 801565.7 1556116.3    1.24    45.3      23       5     149       1
B12R3007 800823.6 1556077.3    0.69    19.1       6      23      50       2
B12R5063 801557.2 1556041.2    0.59    19.2      20       5      14       6
B12R1029 801988.5 1555274.5    0.57    20.4       8      17      11      21
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Calibre is now advancing the Blag Project with a program of trenching on high priority structural and geochemical targets. To date results have been returned for a total of four preliminary trenches from the Blag Gold Project with an additional six trenches completed and pending assays. Veins range from north-south oriented (unique to Blag) to northeast-southwest oriented (regional trend) and dip steeply. In some trenches, two veins have been encountered and are separated by several metres of andesite host rock containing minor quartz veinlets of similar orientation. Individual veins/silicified zones can reach 2m width. Trenching is ongoing on other targets defined by LiDAR topographic anomalies and coincident anomalous soil geochemistry.

Results from the initial Blag trenches include:

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Trench ID       From (m)       To (m) Interval (m)      Au (pm)     Ag (ppm)
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BTR12-064          12.7         14.1          1.4         0.12         39.7
BTR12-065          18.2         19.0          0.8         0.10         12.3
BTR12-068          16.0         18.0          2.0         0.51          6.1
BTR12-070          15.0         16.0          1.0         0.84         11.7
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Western Siuna Gold-Silver-Copper District is in the south-western portion of the Borosi Concessions and contains the Cerro Aeropuerto gold-silver deposit as well as the past producing La Luz gold mine. Recent exploration has also included an extensive regional program on a large land package located along trend from the known mineralized zones. Highlights of recent advancement include:

1.  Trenching of Cerro Aeropuerto gold system; 

2.  Extensive geological and structural mapping and geochemical sampling of
    the northern extension to the Siuna mineralization has defined areas of
    favourable geology and alteration, including surface samples anomalous
    in gold, silver, copper, lead and zinc; and 

3.  Additional work will include follow up detailed soil sampling on
    structural and geological targets and trenching of high priority
    anomalies. 

A series of five trenches at Cerro Aeropuerto were re-mapped and re-sampled. Structural data from Calibre geologists show a dominant N-S oriented mineralized zone with dips ranging between 72 and 90 degrees (west dipping). The structural zones range from 0.1 to 5.3 meters in width and contain remnant sulphide. Results confirm significant gold, zinc, silver, and copper mineralization in all trenches including 11.0 m grading 0.56 g/t Au and 7.6 g/t Ag and 14.0m grading 1.7 g/t Au and 8.5 g/t Ag. Cerro Aeropuerto trench intercepts are tabulated below:

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               From     To    Int     Au     Ag     Cu     Zn     Pb     Mo
Trench ID        (m)    (m)    (m)  (g/t)  (g/t)  (ppm)  (ppm)  (ppm)  (ppm)
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CATR12-001     0.00  11.00   11.0   0.56    7.6    565   3368    534   15.9
               2.00   3.70    1.7   1.04    7.0    890   5552    672   24.0
CATR12-002     0.00  14.00   14.0   1.70    8.5   1153   1966     94    6.6
               0.00   3.00    3.0   3.95   11.6   2378   3201    232    4.4
               4.60   8.40    3.8   1.50    7.4    938   1672     52    9.4
CATR12-003     0.00   7.00    7.0   0.93    8.7   1705   2892    202    3.6
               1.00   2.00    1.0   4.13    6.1   2250   5493   1094    3.0
CATR12-004    16.00  20.70    4.7   0.74    7.4    881    817    238    3.5
              19.50  20.70    1.2   1.50   13.4   1522    430    438    7.0
              32.00  51.90   19.9   0.27    1.6     78    310     39    0.8
CATR12-005     0.00  34.00   34.0   0.64   13.1    233    827    305    2.4
               1.60   3.00    1.4   1.51    4.5    139   1212   1212    2.0
              30.00   34.0    4.0   2.23   90.5   1538   1791   1982    7.8
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Reconnaissance mapping and prospecting in the northern Siuna area has confirmed bedrock to be composed of andesite volcanics similar in character to those encountered in the Bonanza and Riscos de Oro areas. A total of 43 stream sediment samples have been collected in the northern Siuna area including in several drainages where visible gold was noted. Results are pending and additional sampling is on-going. The presence of epithermal-style quartz veins in the northern Siuna concessions suggests a possible extension of the Bonanza gold camp located 25 km to the north. Additional prospects of interest include La Toboba where strongly silicified andesite enveloped by diorite and cut by a northwest oriented fault contains disseminated pyrite. At the Roskilete gold target diorite units are exposed along a northwest oriented drainage containing abundant active and abandoned placer gold workings and quartz veining. Assays are pending for these targets that may be prospective for either porphyry and/or skarn-style mineralization.

In the central portion of the Siuna camp numerous northeast and northwest oriented, steeply dipping fault zones have been observed in outcrops of local creeks and rivers. The geochemical signature of rock sample results (Au-Ag-Cu-Pb) of the Casa Blanca prospect points toward an epithermal nature for the mineralization. La Virgen and Cerro Asa have Au-As +/- Cu signatures indicative of possible porphyry and/or skarn systems while Montes de Oro has a Au-Zn-As +/- Cu signature is more characteristic of skarn-style mineralization. Individual samples assayed up to 1.32% Cu, 3.30 g/t Au, and 25.2 g/t Ag.

Mr. Gregory Smith, P.Geo., the President and CEO of the Company, is the Qualified Person as defined by NI 43-101, and is responsible for the accuracy of the technical data and information contained in this news release.

About Calibre Mining Corp.

Calibre Mining Corp. is a TSX Venture Exchange listed company (TSX VENTURE:CXB) that is focused on the acquisition, exploration and development of gold and silver deposits in Central America. The Company is focused on its 100% owned Riscos de Oro gold-silver deposit, the drilling program at the Primavera gold-copper project in conjunction with B2Gold Corp. and the drilling program on the Rosita copper-gold-silver project in conjunction with Alder Resources Ltd. 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.

Contacts:
Calibre Mining Corp.
Mark Carruthers
604-681-9944
www.calibremining.com