BonanzaThe Bonanza Camp is comprised of the 100% Calibre owned Bonanza H-1 and Pispis concessions which have a combined area of 23,917 ha (239 sq. km) and make up the west-northwest portion of Calibre's larger Borosi land package. The Bonanza district is host to numerous economic low-sulphidation style gold-silver epithermal veins which have been the basis for past and current production at the Bonanza Mine. The Bonanza Mine is owned and operated by the private, arms-length company Hemco Nicaragua SA ("Hemco") and is located on Hemco held mining concessions.
Figure 1. Calibre's Bonanza Camp location View PDF
Calibre's concessions in the Bonanza district are a contiguous group of claims which cover the northeast and southwest extensions of the Bonanza epithermal vein trend. This 18+ kilometre trend is highly prospective for economic gold, silver, and base metal mineralization and has a significant production history. To date the Bonanza Mine has produced over 2.6 million ounces of gold from low-sulphidation epithermal veins*.
Bonanza mine production*:* Historical production from (Arengi 2002).
2,626,533 ounces gold
611,131 ounces silver
Geology of the Bonanza Camp
The Bonanza Camp is composed of two northeast trending sequences of Tertiary aged Matagalpa andesitic volcanics that flank a central andesitic pyroclastic unit. To the north, these pyroclastics become progressively more felsic as they approach an intrusion of similar composition. Veins located in the southwest portion of the trend are typically base metal-rich, while those in the northeast are gold-silver-rich. The lack of exposure of significant intrusive rocks or rocks of the Todos Santos Formation suggests minimal erosion and overall good preservation of the contained epithermal systems.
Exploration at the Bonanza Camp
Recent exploration has focused on the northeast extension of the Bonanza vein trend. A combination of mapping, prospecting, soil sampling and trenching over a 2.5 km x 2.0 km area has delineated several sets of gold-bearing quartz veins extending northeast for 2.5 kilometres from the southern concession boundary.
A series of six trenches were cut across two sub-parallel silicified zones containing crystalline quartz veinlets hosted within argillically altered andesite (Figure 2). Highlights of the trenching include 7.30 g/t gold over 4.7 metres in trench BTR10-18 and 1.35 g/t gold over10.9 metres in trench BTR10-29 (Table 1).
Results from these trenches confirm that mineralization extends at least 600 metres along strike of what is inferred to be the northeast extension of the Washington vein set, part of the Panama Group of gold rich veins currently being mined by Hemco. Exploration work is ongoing at the Bonanza Camp.
|TRENCH||From (m)||To (m)||Interval (m)||Au (g/t)|
Figure 2. Significant trench and geochemical results for NE Bonanza View PDF
Figure 3. Panorama of Trench BTR10-18
Figure 4. Silicified vein structure (BTR10-18)
Figure 5. Trench BTR10-29
Figure 6. Silicified vein structure (BTR10-29)