Calibre Mining Corp. Initiates Diamond Drill Program at Primavera Gold-Copper Prospect, Nicaragua

VANCOUVER, BRITISH COLUMBIA -- (Marketwire - Nov. 28, 2011) - Douglas Forster, Chairman of Calibre Mining Corp. (TSX VENTURE:CXB) (the “Company“ or “Calibre“) is pleased to announce that the Company has initiated a Phase 1 diamond drilling program on the Company's Primavera gold-copper prospect on the Borosi Project in Northeast Nicaragua. The Phase 1 drill program is the first drill test of the newly discovered Primavera gold-copper prospect which encompasses an 850 metre by 300 metre gold and copper soil anomaly which has been explored by 6 trenches totalling 497 metres. Over the next 30 days Calibre is planning to complete 3 drill holes totalling approximately 500 metres.

Calibre has also received complete assay results for Trench PRTR11-014 which is the final completed trench on the Primavera target. PRTR11-014 intersected continuous gold and copper mineralization over the entire excavated length of the trench and returned a weighted average grade of 0.42 g/t Au and 1286 ppm Cu over 51.7 metres (170 feet) with the mineralization being open for expansion in all directions (see Table 1 below). Trench PRTR11-014 was excavated in a north-easterly direction and starts approximately 5.0 metres from the east end of trench TRPR11-012 which assayed 0.70 g/t Au and 1313 ppm Cu over 58.0 metres (see Calibre News Release dated November 14, 2011). The six trenches have been excavated within an 850 metre by 300 metre gold and copper soil anomaly that remains open for expansion in a region that has very limited rock exposure and no documented previous exploration.

Mineralization in the trenches consists of magnetite stockwork veining in highly oxidized and fractured andesite and microdiorite. Banded quartz-magnetite veins and veinlets have also been observed in multiple vein orientations. Textures and mineralization characteristics observed in the trenches are indicative of different zones within a porphyry system.


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
PRTR11-011* 	0.00 	179.40 	179.40 	0.63 	997
PRTR11-012* 	0.00 	58.00 	58.00 	0.70 	1313
including 	0.00 	24.00 	24.00 	1.02 	904
PRTR11-013* 	0.00 	49.50 	49.50 	0.25 	1100
including ** 	43.50 	45.00 	1.50 	4.18 	2749
PRTR11-014 	0.00 	51.70 	51.70 	0.42 	1286
including 	0.00 	18.00 	18.00 	0.74 	583
and 	18.00 	51.70 	33.70 	0.25 	1661

* Assay results for trenches PRTR11-005, PRTR11-010, PRTR11-011, PRTR11-012, and PRTR11-013 were previously released (see Calibre News Releases dated October 3, 2011, October 24, 2011 and November 14, 2011)
** Remainder of gold assays in Trench PRTR11-013 average 0.13 g/t Au in a range of 0.06 to 0.41 g/t Au
- Weighted averages calculated using uncut assays.

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

The Primavera gold-copper prospect is subject to an option agreement with B2Gold Corp., whereby B2Gold may earn up to a 51% interest in specific concessions within the Borosi area by funding CDN $8.0 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 Feasibility Study for an additional 14% interest in the prospect. B2Gold has exercised their option to be the project operator including providing on-site geological supervision of the Primavera drill program.

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



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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