projects

Riscos de Oro Project



The Riscos de Oro deposit is part of the Eastern Borosi Project and is located 20 kilometres northeast of the historic mining town of Rosita. Riscos de Oro is a southwest trending, low sulphidation epithermal gold-silver quartz vein system that has been traced at surface for over 2 kilometres and has an inferred cumulative strike length of 7 kilometres. Rosario Resources operated a small scale open pit and underground mine at site in the late 1970's which is estimated to have produced 40,826 ounces of gold and 2,567,808 ounces of silver (Lehman, 1981). The underground development consisted of two levels (150ft and 300ft) accessed by a vertical shaft. Two additional mines were operated in the region by Rosario during the same period exploiting gold and silver from low-sulphidation style epithermal quartz veins (Blag, California).

The Riscos de Oro vein system is hosted in an interbedded and variable andesite volcanic sequence that repeats six to ten times at depth. The units have been classified as vent-proximal flows and tuffs with interspersed hypabyssal intrusions (dikes-sills). The sequence transitions from subaerial lithic facies through to coherent flow facies and includes andesitic crystal lithic tuff, hematitic ash tuff, amygdaloidal andesite, porphyritic andesite and aphanitic andesite. The contacts within the sequence are mostly gradational and often do not have definitive contacts. The principal vein has an average orientation of 233/60 (NE-SW) and is believed to have undergone both sinistral strike and normal dip slip during its formation (i.e. oblique slip). Multiple reactivation events are recorded in drill core in the form of reworked quartz vein breccias. Where intact the veins are classic colloform banded low sulphidation style, with a sulphide content ranging from 3% to 10% (see photos below). The observed sulphide assemblage includes pyrite, sphalerite, galena, argentite and minor chalcopyrite. A 2 to 3 metre wide silicified and propylitic alteration halo is often observed in the host rocks immediately adjacent to the veins. Quartz-calcite stockwork veining is also common for several metres surrounding the vein and is more intense in the footwall. In addition to the principal vein at least two other sub-parallel veins have been intersected in drill core both containing significant gold and silver values.

The 2012 Riscos de Oro Mineral Resource estimate is based on 9,494 metres in 37 diamond drill holes completed by Calibre in 2010 and 2011 as well as 22 historic drill holes totaling 3126.8 metres. The drilling was generally spaced at 25 to 50 metre intervals along strike and down dip. Significant drill results were returned over a strike length of 625 metres and to a depth of 300 metres. Vein intercepts ranged from 1.39 to 10.60 metres in width. Additional data related to historical drilling, underground development and past production was used to aid in the geological interpretation. The Riscos de Oro vein system is open for expansion both along strike and at depth.


2012 Inferred Mineral Resource Summary (0.6 g/t AuEq cutoff)
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.
Click to Enlarge
Epithermal vein intersection displaying colloform, chalcedonic and banded textures containing disseminated sulphides to 3% (RD10-005; 242.88-247.06m).
Riscos de Oro Drill Hole RD10-005
 
Gritty quartz vein breccia containing light grey quartz fragments (RD11-011; 198.50m).
Riscos de Oro Drill Hole RD11-011
 
Banded epithermal quartz vein with very fine-grained dark grey sulphide bands (RD11-011; 200.00m).
Riscos de Oro Drill Hole RD11-011
 
Quartz vein breccia containing fragments of banded epithermal quartz set in a light grey quartz matrix; chlorite filling on fractures (RD11-015; 182.40m).
Riscos de Oro Drill Hole RD11-015
 
Colloform banded epithermal quartz vein (RD11-015; 183.80m).
Riscos de Oro Drill Hole RD11-015
 
Brecciated and banded epithermal quartz vein (RD11-016).
Riscos de Oro Drill Hole RD11-016
 

Click to Enlarge
Drill
Updated Drill Map
Drill
Soil Anomlay Map
Cross Sections Map
Cross Sections Map

Drill
Diamond Drilling on Riscos de Oro Project 2011
Drill
Drill Targets

Hole ID Zone From (m) To (m) Interval (m) Gold (g/t) Silver (g/t)
RD10-001 Upper 177.60 183.40 5.80 2.44 292.60
including 177.60 178.40 0.80 14.05 1990.00
Middle 186.10 190.25 4.15 1.01 4.85
RD10-002 Upper 205.40 210.30 4.90 0.97 28.72
including 207.40 209.40 2.00 1.77 56.40
RD11-003 Lower 296.30 299.70 3.40 8.81 55.74
including 297.40 299.70 2.30 11.05 72.30
RD10-005 Lower 242.91 247.05 4.14 9.04 30.02
including 244.75 245.83 1.08 13.30 37.80
RD10-009 Upper 160.70 169.23 8.53 4.23 384.86
including 160.70 161.80 1.10 4.10 99.00
and 162.53 163.80 1.27 9.22 217.00
and 164.70 166.00 1.30 1.76 113.00
and 168.28 169.23 0.95 17.85 2810.00
and 172.20 173.87 1.67 1.53 32.10
RD11-010 Upper 167.10 168.60 1.50 5.98 9.10
Middle 187.40 191.60 4.20 2.50 5.16
Lower 223.00 228.40 5.40 10.25 288.25
including 224.50 226.50 2.00 24.00 714.25
RD11-011 Lower 198.38 202.00 3.62 6.41 139.21
RD11-012 Lower 249.30 259.90 10.60 7.69 211.87
including 249.30 255.95 6.65 9.16 252.50
and 257.90 259.90 2.00 10.02 268.00
RD11-013 Lower 318.04 323.12 5.08 0.82 2.76
RD11-014 Upper 187.87 190.90 3.03 1.54 46.30
RD11-015 Upper 182.00 184.20 2.20 5.44 405.55
RD11-016 Upper 198.50 205.60 7.10 2.72 287.65
including 201.92 205.60 3.68 3.61 518.44
Lower 249.42 253.71 4.29 3.20 13.30
including 249.42 250.42 1.00 12.35 47.00
RD11-017 Upper 223.60 227.50 3.90 9.31 336.06
including 224.96 226.33 1.37 18.70 752.00
RD11-018 Lower 273.03 274.42 1.39 9.11 14.33
and 287.65 289.81 2.16 1.79 5.93
RD11-019 Upper 121.15 126.95 5.80 9.37 64.80
including 125.15 126.95 1.80 13.82 132.10
and 131.50 133.00 1.50 3.05 48.50
RD11-021 Upper 187.74 191.60 3.86 0.24 3.31
Lower 241.80 250.44 8.64 4.40 24.12
including 241.80 244.06 2.26 8.71 29.87
RD11-024 Lower 287.05 289.40 2.35 7.75 15.49
and 291.62 293.19 1.57 2.65 4.60
RD11-025 Upper 136.82 139.77 2.95 4.23 449.80
Lower 220.10 221.50 1.40 0.18 1.60
and 225.93 227.08 1.15 0.11 1.90
RD11-026 Upper 208.84 211.42 2.58 8.74 120.50
Middle 229.47 230.34 0.87 1.22 27.50
Lower 283.10 284.05 0.95 2.48 6.50
RD11-027 Lower 299.00 303.60 4.60 2.28 11.56
including 301.00 302.50 1.50 5.81 26.50
RD11-029 Lower 282.52 284.97 2.45 10.30 56.71
  including 282.52 283.97 1.45 16.30 90.10
RD11-031 Upper 148.50 151.15 2.65 3.33 11.22
including 148.50 149.60 1.10 6.06 14.90
Lower 219.06 223.60 4.54 2.03 12.18
including 221.10 222.10 1.00 7.25 15.80
RD11-033 Upper 211.00 219.00 8.00 2.38 2.28
including 214.00 219.00 5.00 3.66 2.32
Lower 272.87 274.45 1.58 1.94 6.90
RD11-035 Upper 117.75 119.43 1.68 0.19 1.40
RD11-036 Upper 134.63 138.00 3.37 0.22 10.06
RD11-037 Lower 250.39 254.60 4.21 8.66 37.57
including 251.79 252.98 1.19 24.74 84.60

No significant results reported for drill holes: RD10-004, -006, -007, RD11-020, -022, -023, -028, -030, -032, -034

Drill hole RD10-008 was lost due to bad ground.

Mr. Gregory Smith, P. Geo., president & CEO for Calibre Mining is the qualified Person as defined by NI 43-101 and has prepared and approved the technical data and information on this webpage.