Calibre Mining Corp. Trenches 1.53 g/t Gold Over 51.25 Metres at the Primavera Gold-Copper Prospect

VANCOUVER, BRITISH COLUMBIA -- (Marketwire - Oct. 3, 2011) - Douglas Forster, Chairman of Calibre Mining Corp. (TSX VENTURE: CXB) (the "Company" or "Calibre"), is pleased to announce that the Company has received complete assay results from the initial two trenches excavated on the newly discovered Primavera gold-copper prospect on the Borosi Project in northeast Nicaragua.

Both trenches intersected continuous gold and associated copper mineralization over their entire excavated lengths. Weighted averages for the trenches include; Trench PRTR11-005 assaying 1.53 g/t Au and 680 ppm Cu over 51.25 metres (open) and Trench PRTR11-010 assaying 0.78 g/t Au and 980 ppm Cu over 107.0 metres (open) (see Table 1 below).

The two trenches are located approximately 100 metres apart with PRTR11-005 trending east-west and PRTR11-010 trending north-south. The trenches are part of a series of five recently excavated trenches located within an 850 metre by 300 metre coincident gold-copper soil anomaly in a region with very limited rock exposure. Mineralization in the trenches is characterised by abundant stockwork veining and the area is thought to be prospective for porphyry related gold-copper mineralization. The mineralized interval in the trenches is open in both directions and the trenching and sampling program is on-going.

Douglas Forster, Chairman stated: "The Primavera gold-copper prospect is a potentially porphyry-related bulk tonnage gold-copper target located within a district that has produced over 5 million ounces of gold and 300 million pounds of copper. We are very encouraged by the initial trench results from this extensive gold-copper system and this new discovery highlights the underexplored nature of the historic 'Mining Triangle' in northeast Nicaragua. In addition to the trenching program at Primavera, Calibre has two drill rigs completing a resource delineation drill program at our 100% owned Riscos de Oro gold-silver project located 22 km northeast of the Primavera prospect."

For a detailed location map, please view the Primavera gold-copper prospect plan map on the Company's website at www.calibremining.com.

Table 1 – Primavera Trench Sampling Results

Trench ID 	From (m) 	To (m) 	Interval (m) 	Gold (g/t) 	Copper (ppm)
PRTR11-005* 	0.00 	51.25 	51.25 	1.53 	680
					
PRTR11-010 	0.00 	107.00 	107.00 	0.78 	980
Including 	4.00 	27.00 	23.00 	1.03 	695

*Trench PRTR11-005 was extended with partial assay results for PRTR11-005 being previously released (see Calibre News Release dated Aug 3/11).
-Weighted averages calculated using uncut assays.

The Primavera gold-copper prospect is subject to an option agreement with B2Gold, whereby Calibre is acting as operator and B2Gold may earn up to a 51% interest in specific concessions within the Borosi area by funding CDN $8 million in expenditures by June 2014. Once the earn-in is complete, B2Gold may elect to carry an individual prospect within the concession area through to a Preliminary Economic Assessment for an additional 14% interest in the prospect.

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 Inspectorate Labs in Managua, Nicaragua for sample preparation and then to Inspectorate 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., Vice President, Exploration and a Qualified Person ("QP") as defined by NI 43-101.


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. Calibre has outlined a NI 43-101 compliant Inferred resource totalling 835,450 ounces of gold and 4,288,070 ounces of silver at its 100% owned Borosi Project, Nicaragua. The Company is focused on a resource delineation drill program at its 100% owned Riscos de Oro gold-silver project and the trenching and drilling program at the Primavera gold-copper prospect in conjunction with B2 Gold. Major shareholders of Calibre include gold producer Yamana Gold Inc. and investment fund Sun Valley Gold.


CALIBRE MINING CORP.

Douglas Forster
M.Sc., P.Geo., Chairman



Cautionary Note Regarding Forward Looking Statements

Safe Harbour 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.

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Contact Information

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