Rio Tinto Option Rosita District - 100% Owned Cxb
The 214 km2 Rosita District is host to a series of advanced targets including the Santa Maria, high grade gold-silver low sulphidation epithermal vein system. Other advanced Targets include Minnesota, Terciopelo, and others previously within the B2Gold Joint Venture.
The Santa Maria Project consists of a well-defined low sulphidation epithermal mineralization. Previous work by Calibre includes 16.3 line kilometres of soil sampling (812 samples), 55 rock samples as well as geological mapping over 9 km2. Low Sulphidation Epithermal vein mineralization is confirmed over 800 metres of strike length, and inferred over a total strike length of three kilometres. Rock sample results include; 64.1 g/t Au, 109 g/t Ag, 0.513% Cu, and 3.75% Pb,. Soil results define a 1000m x 50-100m Au-Pb-Zn ± Cu soil anomaly with results to 666 ppb Au, 1190 ppm Pb, 1050 ppm Zn and 889 ppm Cu.
The central portion of the Santa Maria Project area has been subjected to intermittent artisanal mining activity along a strike length of 800m. Exposures are largely limited to shallow shafts and pits which have been excavated by artisanal groups; rare float material is located in some areas. Sampling by Calibre has consistently returned anomalous gold and silver with highlighted results including;
|SAMPLE||LITHOLOGY||TYPE||AU G/T||AG G/T||CU PPM||PB PPM|
Highlights of the Maiden 2017 Santa Maria Diamond Drilling
|HOLE ID||FROM M||TO M||LENGTH (M)||AUEQ G/T||AU G/T||AG G/T||CU %||ZN %|
- Intervals are core lengths / true width are estimated to be 70-80% of lengths.
- Length weighted averages from uncut assays (NSV = no significant values).
- drill holes 001, 003, and 008 previously reported – see News Release July 5 2017.
- AuEq calculated using; $1300 Au, $20 Ag, $2.50 Cu, and $1.25 Zn with 100% recoveries
Two additional holes were drilled in the northern extension of the drilled area. Drill hole SM17-012 is a 50 metre step out from the discovery hole SM17-001 which intersected 4.95 m grading 4.16 AuEq g/t (1.51 g/t Au, 24.7 Ag, 1.72 % Cu) and was successful intersecting the highest grade interval in the maiden drilling program which returned 5.85 m grading 7.50 AuEq g/t (2.02 g/t Au, 58.6 Ag, 3.46 % Cu). A further step out an additional 50 metres north, drill hole SM17-013, continued to intersect the structure returning 4.30 m grading 2.55 AuEq g/t (0.12 g/t Au, 13.8 g/t Ag, 1.68% Cu). Based on the drilling completed to date the gold-silver mineralized structure in increasing in copper content to the north.
New results also include three holes drilled on the southern portion of the structure which returned; SM17-009 with 1.65 m grading 1.30 AuEq g/t (0.30 g/t Au, 9.9 Ag, 0.34 % Cu, 0.63 % Zn), SM17-010 with 2.31 m grading 0.99 AuEq g/t (0.35 g/t Au, 32.4 Ag, 0.03 % Cu, 0.16 % Zn), and SM17-011 with 0.30 m grading 0.61 AuEq g/t (0.15 g/t Au, 13.5 Ag, 0.09 % Cu, 0.20 % Zn) Intercepts in the southern end of the drill tested portion of the structure continue to have anomalous gold and silver associated with elevated zinc and lesser copper with this metal distribution interpreted to be related to greater distance from source relative to the northern portion of the structure.
The 2017 maiden drill program at Santa Maria consisted of 13 diamond drill holes totaling 2100 metres. The drilling tested 800 metres of strike length to depths of between 50 and 100 metres below surface.
Results define a northern segment 300 metres in strike length with gold-silver mineralization associated with high copper values transitioning in the central portion which contains variable amounts of both copper and zinc and 200 metres further to the south where it is characterized by low copper and high zinc. The overall Santa Maria geochemical anomaly has been traced for more than three kilometres. The northern portion of the anomaly is adjacent to a kilometer-scale intrusive which one potential source for the mineralized fluids is. Additional work consisting of wide-spaced soil sampling, rock sampling, and geological mapping is planned for this area.
Existing targets with potential for further gold-silver-copper-zinc discoveries on the Santa Maria Project include both the northern and southern structural extensions to the drill tested area (where additional multi-element anomalies have been defined), additional sub-parallel structures which have been identified based on rock and soil anomalies, intrusive related mineralization associated with the mapped granodiorite centered two kilometres north of the current drilling, as well as skarn zones hosted in previously recognized altered limestone and sedimentary rocks.
The 100% owned Rosita District also hosts the Minnesota Gold Project. 2014 reconnaissance diamond drilling program at the Minnesota gold project consisted of seven widely spaced drill holes totaling 992 metres which tested three areas along the 3.5 km by 1.0 km trend of the defined by a strong auger and gold-in soil anomaly and surface rock sampling. Drilling results include: 31.35 metres grading 0.63 g/t Au including 12.40 metres grading 1.07 g/t Au and 47.0 metres grading 0.63 g/t Au including 4.50 metres grading 3.43 g/t Au.
Additional Targets within the 100% owned Rosita District include Terciopelo, Fruta de Pan, and others.