Calibre Mining Corp.
TSX VENTURE : CXB

Calibre Mining Corp.

September 05, 2012 10:11 ET

Calibre Announces NI 43-101 Inferred Resource Estimate Containing 222,300 oz Au and 4,142,000 oz Ag (287,100 oz AuEq) at the 100% Owned Riscos de Oro Deposit, Borosi Project, Nicaragua

Calibre 100% Owned Inferred Resources on the Borosi Project Total 1,057,750 ozs Gold, 8,430,070 oz Ag (1,190,000 oz AuEq.) in 3 Gold-Silver Deposits

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 5, 2012) - Calibre Mining Corp. (TSX VENTURE:CXB) (the "Company" or "Calibre") is pleased to announce a National Instrument 43-101 Inferred Resource Estimate at the Company's 100% owned Riscos de Oro Deposit on the Borosi Project, northeast Nicaragua. The Inferred Resource Estimated at a cut off grade of 0.6 g/t AuEq is 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.) as outlined in the table below:

Riscos de Oro Project, Nicaragua
2012 Inferred Mineral Resource Summary

Zone Tonnes Grade
(Au g/t)
Grade
(Ag g/t)
Grade
(AuEq g/t)
Contained
Au (ounces)
Contained
Ag (ounces)
Contained
(ounces AuEq)
Upper 1,539,000 2.45 64.42 3.46 121,200 3,188,000
Lower 620,000 5.07 47.87 5.82 101,100 954,000
Total 2,159,000 3.20 59.67 4.14 222,300 4,142,000 287,100
  1. CIM definition standards were followed for the resource estimate.
  2. The 2012 resource models used Inverse Distance grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids.
  3. A base cutoff grade of 0.6 g/t AuEq was used for reporting resources with capping of silver grades at 591 g/t.
  4. A density of 2.65 g/cm3 was applied.
  5. Numbers may not add exactly due to rounding.
  6. Gold Equivalent (AuEq) calculated using $1264 /oz Au for gold and $19.78/oz Ag for silver and metallurgical recoveries and net smelter returns are assumed to be 100%.
  7. Mineral Resources that are not mineral reserves do not have economic viability
  8. The quantity and grade of reported inferred resources in this estimation are uncertain in nature and there has been insufficient exploration to define these inferred resources as an indicated or measured mineral resource and it is uncertain if further exploration will result in upgrading them to an indicated or measured mineral resource category.

President and CEO, Greg Smith, states; "We are extremely encouraged with this initial resource estimate at the Riscos de Oro gold-silver deposit. The resource is open in all directions and is contained within less than 700 metres of the defined seven kilometre strike length to the Riscos de Oro structure. As such, we believe there is potential to significantly expand this resource in the near future." Mr Smith adds, "The Riscos de Oro system is a classic low sulphidation epithermal structure and, as is typical of these types of deposits there continues to be tremendous upside potential for delineating additional resources. Calibre has identified a series of high priority drill targets including; the up dip portion of the lower zone which was not tested by the previous drilling, as well as along strike and down dip extensions."

The Resource Estimate was prepared by independent qualified person Todd McCracken, P. Geo. of Tetra Tech Inc. ("Tetra Tech"). The mineral resource estimate is based on the combination of geological modeling, geostatistics and conventional block modeling using the Inverse Distance method of grade interpolation. The mineral resources were estimated using a block model with parent blocks of 20m X 20m X 5m split three times into sub-blocks. The geological model including mineralized intercepts were generated by Calibre personnel and then audited by Tetra Tech. The QAQC protocols and corresponding sample preparation and shipment procedures for the Calibre drilling at Riscos de Oro have been reviewed by Tetra Tech.

A technical report is being prepared and will be filed in the next 45 days.

The Resource Estimate also evaluated the Riscos de Oro Deposit at a range of cut off grades between 0.4 and 2.0 g/t AuEq. Results are as follows;

AuEq
CUT-OFF
TONNES Grade
AuEq g/t
Grade
Au g/t
Grade
Ag g/t
Contained
Au oz
Contained
Ag oz
Contained
AuEq oz
0.4 2,255,000 3.98 3.08 57.56 223,290 4,173,423 288,599
0.6 2,159,000 4.14 3.20 59.67 222,257 4,142,076 287,075
0.8 2,037,000 4.34 3.36 62.41 220,309 4,087,071 284,266
1.0 1,917,000 4.56 3.53 65.27 217,797 4,023,009 280,752
1.2 1,807,000 4.77 3.70 68.17 214,918 3,960,356 276,893
1.4 1,696,000 4.99 3.88 71.41 211,325 3,893,867 272,259
1.6 1,595,000 5.21 4.05 74.62 207,545 3,826,497 267,425
1.8 1,514,000 5.40 4.19 77.55 203,963 3,774,633 263,032
2.0 1,451,000 5.55 4.31 79.59 201,016 3,713,150 259,122

The 2012 Riscos Mineral Resource estimate is based on 9494 metres in 37 diamond drill holes completed by Calibre in 2010 and 2011 as well as 22 existing drill holes totalling 3126.8 metres. The drilling is generally spaced at 25 to 50 metre intervals along strike and down dip. Additional data related to historical drilling, underground development and past production was used to aid in the geological interpretation.

The Riscos de Oro mineralized zone is a low sulphidation epithermal system consisting of two closely spaced zones of quartz veining, stockworks and breccias with associated sulphides. Limited past production occurred from a shallow open pit (now flooded) and two underground levels down to depth below surface of 91 metres previously accessed through a shaft in the late 1970's. No detailed records exist of this past production.

The Riscos de Oro resource complements the existing 100% Calibre owned gold and silver resources on the Borosi Project located at la Luna deposit (10 km south of Riscos) and Cerro Aeropuerto deposit located 60 km southwest. As outlined in the table below the 100% Calibre owned Inferred resources on the Borosi project total 1,057,750 ozs Au and 8,430,070 ozs Ag (1,190,000 oz AuEq.)

100% Calibre Owned Inferred Resource Summary - Borosi Project, Nicaragua

Zone Tonnes Grade
(Au g/t)
Grade
(Ag g/t)
Grade
(Aueq g/t)
Contained
Au (ounces)
Contained
Ag (ounces)
Contained
Aueq (ounces)
La Luna 2,539,000 1.56 14.01 1.78 127,700 1,143,570 146,000
C. Aeropuerto 6,052,000 3.64 16.16 3.89 707,750 3,144,500 757,000
Riscos de Oro 2,159,000 3.20 59.67 4.14 222,300 4,142,000 287,000
Total 1,057,750 8,430,070 1,190,000
  1. Resource models used Inverse Distance grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids and a base cutoff grade of 0.6 g/t.
  2. Resource Estimates for La Luna and Cerro Aeropuerto detailed in Technical Report titled NI 43-101 Technical Report and Resource Estimation of the Cerro Aeropuerto and La Luna Deposits, Borosi Concessions, Nicaragua by Todd McCracken, dated April 11, 2011.
  3. Numbers may not add exactly due to rounding.
  4. Gold Equivalent (AuEq) for Riscos de Oro was calculated using $1264 /oz Au for gold and $19.78/oz Ag for silver, and metallurgical recoveries and net smelter returns are assumed to be 100%.
  5. Gold Equivalent (AuEq) for La Luna and C. Aeropurto was calculated using $1058/oz Au for gold and $16.75/oz Ag for silver, and metallurgical recoveries and net smelter returns are assumed to be 100%.
  6. Mineral Resources that are not mineral reserves do not have economic viability

The Riscos de Oro resource estimate data in this news release was read and approved by Todd McCracken, P.Geo. of Tetra Tech., who is independent of Calibre and a Qualified Person ("QP") as defined by National Instrument 43-101.

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.

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