Large land package in strategic location
Calibre has a 100% interest in the Borosi gold-copper concessions consisting of 71,000 hectares of contiguous mining and exploration concessions in the highly prolific but underexplored Mining Triangle in northeastern Nicaragua. The Borosi concessions are named after the three historical producing regions -- Bonanza, Rosita and Siuna. The concessions are located approximately 230 kilometres northeast of the capital city of Managua and 80 kilometres west of the port town of Puerto Cabezas. Three small towns (Siuna, Rosita and Bonanza) are located within the concessions.
Borosi located in historic Mining Triangle of Nicaragua
The Mining Triangle of Nicaragua is one of the most prolific mining districts of Central America. Historical production in the Mining Triangle district is estimated* at over:
5 million ounces gold
4 million ounces silver
305 million lbs copper
Two major historic mines operated on the Borosi concessions as recently as the early 1980s -- the La Luz-Siuna gold mine and Santa Rita copper mine. The La Luz-Siuna mine produced approximately 2.3 million ounces of gold and the Santa Rita mine produced approximately 350 million pounds of copper from skarn deposits*. A number of smaller past producers are also located on the Borosi concessions including the La Luna, Riscos de Oro and Blag historic mines.
Gold is currently produced at the Bonanza gold mine. Calibre's concessions in the Bonanza district are contiguous claims surrounding the Bonanza mine, which is owned and operated by a private, arms-length company. The Bonanza mine has produced over 2.6 million ounces of gold from low-sulphidation epithermal veins since 1939*.
Potential for two major types of mineral deposits
The Borosi concessions have has the potential to host two major types of mineralization:
Low sulphidation epithermal veins (gold and silver)
Skarns and associated porphyry mineralization (gold and copper)
Numerous mineral prospects and projects located within four camps
The Borosi concessions are subdivided into four regional camps based on the dominant geology and type of mineralization:
Eastern Epithermal camp
Rosita camp
Bonanza camp
Siuna camp
Calibre has over 20 mineral prospect and projects that have the potential to host significant gold, silver and copper mineralization.
Multi-faceted C$2.5 million exploration program in 2009/2010 season
A C$2.5 million exploration program for the 2009/2010 exploration season at Borosi was announced in September 2009. The exploration program is being funded by B2 Gold Corp. with Calibre as operator. The aggressive exploration program is being conducted to improve the understanding and potential of several mineral systems at Borosi and to advance a number of high priority precious and base metal projects.
The first facet of the exploration program is grassroots exploration and consists of property-wide geological mapping and data compilation plus mapping, sampling and descriptions of mineral prospects. Grassroots exploration provides a property-wide framework for future exploration and a better understanding of the potential of the different camps and each of the known mineral prospects.
The second facet of the exploration program is focused on target delineation work on mineral prospects located in the Eastern Epithermal and Rosita camps. This exploration consists of detailed mapping, soil and rock sampling and trenching of high priority prospects. The intent of the target delineation work is to advance the best mineral prospects through to projects in the drill testing stage.
Diamond drilling is the third facet of the exploration program. Drilling of projects provides a better understand the geometry and potential for mineralization -- both epithermal vein and skarn/porphyry mineralization.
Comprehensive grassroots and target delineation work
The initial grassroots and target delineation exploration program focused on the Eastern Epithermal and Rostita camp and has accomplished the following to date:
1:10,000 scale mapping over 7,100 hectares
1,397 lithology point stations collected
671 rock samples collected
71 line-kilometres of soil sampling
788 metres of trenching
Outlined new epithermal veins from rock and soil sampling
Outlined potential skarn/porphyry mineralization
Three projects in diamond drill stage
The 2009/2010 exploration program has been successful in outlining new gold-silver epithermal zones and a high grade gold-copper prospect. During the current exploration season, three projects have rapidly advanced through grassroots exploration, mapping, sampling and trenching through to the drill testing stage. Systematic exploration of additional mineral prospects is ongoing to define additional drill targets.
The approximate 6,000 metre drill program for 2009/2010 consists of diamond drilling three distinct projects:
Bambana copper-gold project, Rosita camp
La Luna gold-silver project, Eastern Epithermal camp
Riscos de Oro gold-silver project, Eastern Epithermal camp
Regional geology at Borosi
Basement rocks in the region consist of northeast trending interbedded sequences of limestone, (calcareous) mudstone, and greywacke of the Early Cretaceous Todos Santos Formation. These units host most of the reported skarn mineralization. Sedimentary rocks may be locally interbedded with pre-Matagalpa andesitic tuffs and flows of Cretaceous age. Near continuous volcanism from the late Cretaceous to mid-Tertiary resulted in the intrusion of numerous felsic to intermediate composition stocks, plugs and dikes with a dominant northeast orientation. Porphyry style mineralization is reported in some of these intrusions. The associated Matagalpa andesitic to basaltic volcanics and pyroclastics are widely distributed through the region and host most of the low-sulphidation style epithermal mineralization.
Calibre as operator at Borosi
Calibre purchased a 100% interest in the Borosi concessions from Yamana Gold in July 2009 and subsequently entered into a joint venture agreement with B2Gold to further explore and develop the project. Under the terms of the agreement, B2Gold may earn a 51% interest in the Borosi concessions by completing C$8 million of exploration expenditures over a three year period. In September 2009, the Management Committee approved a C$2.5 million exploration program for the Borosi concessions, with Calibre acting as operator.
