Calibre Mining Corp.
TSX VENTURE : CXB

Calibre Mining Corp.

March 31, 2010 09:00 ET

Calibre Initiates Drill Program at Borosi Gold-Copper Project, Nicaragua

VANCOUVER, BRITISH COLUMBIA--(Marketwire - March 31, 2010) - Calibre Mining Corp. (TSX VENTURE:CXB) (the "Company" or "Calibre") is pleased to report that the first drill hole of a planned 26 hole, 6,000 metre diamond drill program has been completed on the Borosi gold-copper project in northeast Nicaragua. The Borosi project covers approximately 71,000 hectares within the historic Mining Triangle of Nicaragua. The current drill program at Borosi consists of drill testing three distinct gold prospects: the Bambana, La Luna and Riscos de Oro targets. In addition, systematic exploration of other high priority targets at Borosi will be ongoing to further define drill targets.

Bambana Target

Bambana is the first of three targets to be drill tested at Borosi. The drill program, which began on March 18th, is testing a 500 metre by 300 metre area that has anomalous gold and copper in soil and coincident geophysical anomalies. Drilling of the second hole has commenced. The Bambana target lies four kilometres northwest of the past producing Rosita copper mine, a copper skarn deposit that is estimated to have produced 305 million pounds of copper over the life of the mine1. The Bambana target area is associated with artisanal gold workings and a small prospecting pit. Calibre's sampling of the prospecting pit returned grades of 1.64 g/t gold, 1,645 g/t silver and 29.9% copper over 0.90 metres.

La Luna Target

Drilling at La Luna will drill test recently discovered gold-bearing epithermal quartz veins and quartz breccias that have been delineated over a strike length of 1,100 metres through a soil sampling and trenching program. Recent trenching results from the La Luna include 3.11 g/t gold over 2.10 metres (BTR10-012). Trench results are outlined in Table 1.

Table 1: La Luna Trenching Results

Trench Area From (m) To (m) Metres Gold (g/t Au)
BTR10-009* La Luna 9.20 13.40 4.20 3.49
BTR10-010 La Luna 12.30 16.00 3.70 2.25
BTR10-011* La Luna 8.50 11.70 3.20 3.92
BTR10-011* La Luna 18.90 20.20 1.30 3.36
BTR10-012 La Luna 7.80 9.90 2.10 3.11
BTR10-017* La Luna 7.50 9.80 2.30 1.45
*previously released

Drilling at La Luna will also test the depth extent of a zone associated with an historical small open cut which assayed 3.56 g/t gold over 12 metres.

Riscos de Oro Gold Target

At Riscos de Oro the drill program will focus on two targets: the main Riscos de Oro vein that contains historical open pit and underground workings; and a possible parallel vein located 800 metres to the northwest. The down dip extensions of the Riscos mine will be drill tested 100 to 150 metres below the abandoned workings and historical Rosario drilling. Historical drill intercepts of 9.43 g/t Au and 163 g/t Ag over 6.2 metres (DDH SG-16), 14.5 g/t Au and 174 g/t Ag over 3.79 metres (DDH SG-17) and 8.06 g/t gold and 563 g/t silver over 4.1 metres (DDH SG-4) were reported from this zone between the 46 metre and 93 metre development levels2. Additional drill holes at Riscos de Oro will follow up on the northeast and southwest extensions of the Riscos vein trend as well as the parallel zone northwest of the Riscos mine.

Quality assurance and quality control procedures include the systematic insertion of blanks, standards and duplicates into the soil and rock sample strings. Samples are placed in sealed bags and shipped directly to ALS CHEMEX labs in North Vancouver, BC for gold fire assay and ICP multi element analyses. The technical content in this news release was read and approved by Roger March, P.Geo., a professional geologist registered in the Province of Newfoundland & Labrador and a qualified person as defined by NI 43-101.

The Borosi gold-copper project is subject to an option agreement, whereby B2Gold may earn an initial 51% in the Borosi concessions by completing C$8 million in exploration expenditures over a period of three years. The Borosi exploration budget through July 2010 is C$2.5 million, with Calibre acting as operator.

Calibre Mining Corp. is an aggressive, well financed, TSX Venture Exchange listed company (TSX VENTURE:CXB) that is focused on the acquisition, exploration and development of gold and copper deposits in Central America. Major shareholders of Calibre include gold producers Yamana Gold Inc. and Kinross Gold Corp.

1 From Arengi et al (2003).
2 Rosario Company Records on Riscos de Oro. Circa 1975 to 1977.

Calibre Mining Corp.

Robert D. Brown, B.Sc., MBA, President and CEO

Cautionary Note Regarding Forward Looking Statements

Safe Harbor Statement under the United States Private Securities Litigation Reform Act of 1995: Except for the statements of historical fact contained herein, the information presented constitutes "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements including but not limited to those with respect to the price of gold, silver or copper, potential mineralization, reserve and resource determination, exploration results, and future plans and objectives of the Company involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievement of Calibre Mining Corp. to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. There can be no assurance that such statements will prove to be accurate as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements.

Neither 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.

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