Calibre Mining has unveiled results for the first four holes of the planned 11 drill holes from the 2015 diamond drilling program on its Montes de Oro gold project, Siuna District, Nicaragua.
Calibre Mining president and CEO Greg Smith said: "These initial results from the 2015 drilling program at Montes de Oro have confirmed the existence of gold mineralization associated with zones of massive sulphide mineralization as well as wide zones of disseminated sulphide mineralization.
"With assays being received for only four holes of a planned eleven hole drill program we are encouraged by the presence of wide-spread gold-bearing sulphide mineralization which correlates well with the 300 metre by 500 metre strong, IP geophysical anomaly on the Montes de Oro Project. We look forward to receiving results for the pending samples and completing the remaining drill holes in this Phase I drilling program."
Drilling at Montes de Oro has intersected wide spread gold and associated base metal mineralization. In general very broad low grade gold mineralization containing zones of higher gold grades is characteristic of the mineralized intervals discovered to date. The massive sulphide zone in drill hole MD15-007 returned 12.13 metres grading 2.42 g/t Au within the wider interval which includes veined and disseminated sulphides and averages 37.71 metres grading 1.19 g/t Au. The massive sulphide interval occurs between 86.7 and 98.8 metres down hole which due to the steep to moderate topography in the area is approximately 25 to 40 metres below surface.
The gold is related with increased concentrations of sulphides within the host rocks including;
- massive sulphide zones, and
- veins, veinlets, disseminations, and replacements in fragments,
- centimetre scale cross-cutting polymetallic quartz veinlets containing a combination of sphalerite-galena-chalcopyrite-arsenopyrite-pyrrhotite-pyrite.
Sulphides consist of pyrrhotite and pyrite, sphalerite, chalcopyrite with lesser arsenopyrite and trace amounts of galena and stibnite. Higher grade gold values are especially closely related to increase in copper in the form of chalcopyrite notably in the massive sulphide zone in hole MD15-007 which averages 0.18% Cu over 12.13 metres.
The gold-bearing massive sulphide zones are concentrated at or near the contacts between andesite hornblende dykes and the calcareous sediments and reactive volcanics. Moderate gold values are also associated with blebby and disseminated sulphide and sulphide only veins found in the more permeable volcanic units most notable a coarse, angular, multi-lithic volcanic breccia. Additional gold mineralization occurs in cross-cutting polymetallic quartz and minor carbonate veinlets with abundant sphalerite, galena, chalcopyrite, arsenopyrite, with minor pyrrhotite and pyrite which appear to be the latest phase of mineralization.
The Siuna District is located in the south-west portion of the Borosi Concessions and contains the past producing La Luz Mine that produced 17.1 million tonnes of ore grading 4.14 g/t gold. Approximately one kilometre south of the La Luz Mine, Calibre has defined an NI 43-101 Inferred Mineral Resource, at the Cerro Aeropuerto gold-silver deposit at a 0.6 g/t AuEq cutoff of 6.0 million tonnes grading 3.64 g/t gold and 16.16 g/t Ag containing 707,750 ozs gold and 3.1 million ozs silver. Montes de Oro is located 10 kilometres north of the La Luz Mine.