Calibre's Joint Venture Partner Alder Resources' Drilling Returns 10 Metres Grading 1.42 % Copper, 0.18 g/t Gold and 20.45 g/t Silver, Rosita Project, Nicaragua

12 sept. 2012
Bambana Drilling Returns a Near Surface Intercept of 13.0 Metres Grading 1.23% Copper, 0.36 g

Vancouver, British Columbia: Calibre Mining Corp. (TSX-V: CXB) (the "Company" or "Calibre") is pleased to present assay results from a diamond drilling program completed on the Rosita D Concession, in northeast Nicaragua under an option agreement with Alder Resources Ltd. (TSX-V: ALR) ("Alder").

Calibre and Alder entered into an option agreement dated August, 2011 whereby Alder can earn a 65% interest in the 3,356 hectare Rosita D concession (the "Property") located within Calibre's 100%-owned Borosi concessions in northeast Nicaragua by expending a total of CDN$4.0 million on exploration on the property and by issuing to Calibre a total of 1,000,000 common shares of Alder over a 4 year period. Alder is the project operator.

The results are for the final six holes from its Phase 1 core drilling program at the Rosita copper-gold-silver project in northeast Nicaragua. Results include a well mineralized intercept that returned 10 metres grading 1.42% copper ("Cu"), 0.18 grams per tonne ("g/t") gold ("Au") and 20.45 g/t silver ("Ag") within a wider intercept that returned 0.50% Cu, 0.08 g/t Au and 6.44 g/t Ag over 53.0 metres. This mineralization was intersected approximately 120 metres below the base of the historic Rosita Pit.

Two holes at the Bambana prospect, four kilometres northwest of Rosita, also returned excellent results with intercepts of 13 metres grading 1.23% Cu, 0.36 g/t Au and 10.63 g/t Ag and 18 metres grading 1.74% Cu, 0.09 g/t Au and 16.65 g/t Ag. In both holes mineralization begins at surface.

Selected highlights of the drill results are presented in Table 1 and illustrated in Figures 1, 2 and 3.

Table 1. Summary of selected final diamond drill results at Santa Rita and Bambana.

Hole ID  Area From
D915 Santa Rita 57.0 63.0 6.0 0.36 0.15 3.07 0.49
  and 96.0 149.0 53.0 0.50 0.08 6.44 0.63
  including 128.0 138.0 10.0 1.42 0.18 20.45 1.77
  and 129.0 133.0 4.0 1.94 0.25 30.05 2.45
D916 Santa Rita 7.0 12.0 5.0 0.33 0.09 1.14 0.40
D917 Santa Rita 0.0 55.0 55.0 0.05 0.31 0.86 0.25
  including 8.0 14.0 6.0 0.19 1.07 3.62 0.90
  and 98.0 105.0 7.0 0.32 0.13 4.37 0.45
  and 165.0 169.0 4.0 0.35 0.55 2.40 0.72
D918 Santa Rita 71.0 85.0 14.0 0.87 0.81 7.96 1.47
D919 Bambana 0.0 13.0 13.0 1.23 0.36 10.63 1.58
D920 Bambana 0.0 18.0 18.0 1.74 0.09 16.65 1.99

NB. Thickness represents drilled width; true widths are unknown at this time. CuEq = Cu% + Au g/t x (0.6033) + Ag g/t x (0.012) and US$2.90/lb Cu, US$1200/oz Au and US$24/oz Ag.

The intercept in hole D915 occurs within a thick, lower grade zone that includes 53.0 metres grading 0.50% Cu, 0.08 g/t Au and 6.44 g/t Ag. Hole D918, collared 250 metres southwest of D915, returned 14 metres grading 0.87% Cu, 0.81 g/t Au and 7.96 g/t Ag also in skarn and starting at 71 metres. Hole D917, located 80 metres west of hole D915, intersected a wide, low grade gold zone that returned 55 metres from surface grading 0.31 g/t Au, with low Cu and Ag values. The mineralization is hosted in skarn, and all three intercepts lie below the central part of the Santa Rita pit (See Figure 2). The average intercept width of the higher grade intercepts is 10.3 metres, and together they define a strike length of 250 metres, and occur over a vertical range of roughly 150 metres. These results, together with those announced previously (See Alder news releases of September 5 and May 31, 2012), have traced mineralization along 1,100 metres from surface to 200 metres vertical depth. The Santa Rita/R-13 mineralized corridor contains most of the historic resources on the Rosita property and these zones will be selectively targeted with in-fill drilling later this year.

At Bambana, northeast directed angle hole D919, located at the T3 Zone, cut 13 metres from surface grading 1.23% Cu, 0.36 g/t Au, and 10.6 g/t Ag. Previous trenching results and panel sampling at T3 returned encouraging results (see Alder news release of June 13, 2012) with up to 29 metres grading 2.09% Cu, 0.19 g/t Au, and 14.6 g/t Ag. Mineralization in D919 is localized in variably oxidized and clay-weathered potassium feldspar-quartz altered andesitic volcanics and diorite containing copper oxides and minor sulphides. Off-set hole D920 returned 18 metres grading 1.74% Cu, 0.09 g/t Au, and 16.65 g/t Ag. The recoveries in this hole were locally very poor, however, the results are consistent with the mineralization encountered to date and as such, the grade is taken as representative. Drilling and trench work has defined a near-surface, good grade, "exotic" copper zone that is open to modest expansion and appears to be rooted within, or proximal to a primary Cu-Au-Ag zone.

The Phase 1 diamond drilling program included 20 holes totaling 5,908.5 metres. Eighteen of the holes were collared in the Santa Rita to R-13 corridor and two holes were drilled at Bambana to test high grade copper oxide mineralization below a trench and two benches. All of the holes intersected varying levels of copper, gold and silver mineralization.

Alder has delineated a stockpile resource at Rosita of 7.95 million tonnes grading 0.62% Cu, 0.46 g/t Au and 9.20 g/t Ag (1.01% CuEq) (see Alder news release of May 9, 2012). This material is at surface and already broken, so could provide a readily available source of mill feed at low cost. Drilling to date has led Alder management to believe that estimated mineral resources will be expanded along the Santa Rita/R-13 corridor and Bambana. Several areas of historic resources are also present that have not yet been tested.

Alder is currently carrying out a geologic mapping, soil sampling and trenching program, designed to test several high quality IP geophysical anomalies, and high grade copper--gold bearing grab samples from the highly prospective Bambana Cu-Au-Ag porphyry prospect, and the El Rastro prospect where artisanal miners are mining gold 1.5 kilometres north of the R-13 pit. Previous work at Bambana has returned 3.32% Cu, 0.22 g/t Au and 37.55 g/t Ag over 12.0 metres in what appears to be related to porphyry-style mineralization in a trench as well as 2.09% Cu, 0.19 g/t Au, 14.6 g/t Ag and 1.98% Cu, 0.14 g/t Au and 14.4 g/t Ag over two 29 metre bench channel samples (See Figure 1). These targets represent significant potential upside for Alder in addition to the Santa Rita and R-13 mineralized zones.

Quality Assurance/Quality Control

All drill holes were collared using HQ-size drill core, and reduced to NQ-size where necessary. Core was loaded on-site into wooden core boxes and transported on a daily basis by Company personnel to Alder's secure field office in Rosita, where geologists logged the holes, and selected intervals for assay. Individual samples of drill core were sawed, using a 10" diamond blade trim saw. Half of the sample was retained in the core box, the rest loaded into a pre-numbered, heavy gauge plastic bag, sealed and then trucked on a weekly basis (by the laboratory or by Company personnel) to Inspectorate Exploration and Mining Services' preparation laboratory in Managua. There, pulps were prepared for shipping to Inspectorate's Analytical laboratory in Vancouver, where each sample was analyzed via fire assay for gold and for copper, silver and 28 other elements using ICP (Inductively Coupled Plasma-atomic emission spectrometry) methods. Alder has implemented an industry standard Quality Assurance/Quality Control program that includes the insertion of certified standards and blanks into the sample stream.

Qualified Person
Mr. Gregory Smith, P.Geo, the President and CEO of Calibre, 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.V: 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"

Greg Smith, P.Geo.
President and CEO

For further information contact:
Mark Carruthers -- Vancouver, Canada
604 681 9944

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.

Figure 1. Location of diamond drill holes at Bambana illustrated on the -100 metre IP chargeability depth slice.

Figure 2. Location of diamond drill holes at Santa Rita reported in this news release.

Figure 3. Longitudinal section along Santa Rita/R-13 corridor, south side.



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