Overview; Calibre Mining Corp. has outlined mineral resources in four areas within the Borosi Concessions.
Within the Projects currently owned 100% by Calibre Inferred Resource total;
55,724,000 tonnes grading 1.34 g/t AuEq containing 2.4 million ounces of gold equivalent.
Additionally resources within the Rosita D JV (33% Calibre) host 211,000 gold equivalent ounces Inferred and 252,000 gold equivalent ounces Indicated.
|Primavera||100% CXB||Au-Cu Porphyry||Inferred||44,974,000|
|C. Aeropuerto||100% CXB||Au Skarn||Inferred||6,052,000|
|EBP (Riscos/Luna)||100% CXB||LS Epithermal||Inferred||4,698,000|
|Rosita D||JV 33% CXB||Cu - Au Skarn||Inferred||5,393,000|
|Rosita D||JV 33% CXB||Cu - Au Skarn||Indicated||6,460,000|
|(Au g/t)||(Ag g/t)||Cu (%)||(Aueq g/t)|
|Rosita D (inferred)||0.49||9.0||0.46||1.22|
|Rosita D (Indicated)||0.47||7.3||0.50||1.21|
|Rosita D (inferred)||85,500||1,564,500||55,100,000||211,337|
|Rosita D (Indicated)||96,700||1,520,500||70,969,000||251,526|
1. Cerro Aeropuerto currently optioned to Centerra Gold
2. Riscos de Oro and La Luna currently optioned to JV with IAMGOLD
Primavera Gold-Copper Porphyry; Calibre Mining Corp. announced the maiden resource on the 100% Owned Primavera Gold-Copper porphyry in December of 2016. The inferred Resources is 45 million tonnes grading 0.84 g/t AuEq containing 1.2 million ounces gold equivalent.
Inferred Resource at a cutoff of 0.5 g/t Au for the Primavera Au-Cu Porphyry Deposit
1. CIM definition standards were followed for the resource estimate.
2. The 2016 resource models used Ordinary Krig grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids (HG=high grade, LG= low grade, sap=saprolite).
3. A base cutoff grade of 0.5 % g/t Au was used for reporting resources.
4. Densities varied by material type and ranged from 2.4 for saprolite to 2.71 for diorite and the volcanics have variable estimated densities using inverse distance.
5. Gold Equivalent (AuEq) calculated using $1300/oz Au for gold, $2.40/lb for Copper, and $20.00/oz Ag for silver and metallurgical recoveries are assumed to equal for all metals.
The Primavera Project NI 43-101 Inferred Resource Estimate was prepared by independent qualified person Todd McCracken, P. Geo. of WSP. The resource estimate is based on the combination of geological modeling, geostatistics and conventional block modeling using the Ordinary Krig methodology of grade interpolation. The mineralized zones were defined by wireframed solids consisting of HG=high grade, LG= low grade, and sap=saprolite. The mineral resources were estimated using a block model with parent blocks of 10m X 10m X 5m. A capping study was made using histograms, probability plots, quantile plots and deciles plots to define the capping values resulting in capping value of; HG: 2.7 g/t Au; 9 g/t Ag; 1% Cu and LG: 1.7 g/t Au, 3.6 g/t Ag and 0.46% Cu.
The WSP Resource Estimate also evaluated the Primavera Deposit at a range of cutoff grades between 0.1 g/t Au and 0.9 g/t Au. Results are as follows;
Inferred Resource at Range of Cutoff Grades for the Primavera Au-Cu Porphyry Deposit
WSP also completed whittle analyses to estimate an open pit-constrained Inferred resource with results as follows;
Open Pit-Constrained Inferred Resource at a 0.5 g/t Au Cutoff- Primavera Au-Cu Porphyry Deposit
1. Whittle optimized open pit.
2. Mining Cost $2.25/t mined, Processing Cost $20/t processed (included G and A and Selling Costs)
3. Mining Dilution 5% @ 0 grade and Mining Recovery 95% both applied globally.
4. Metal Recovery; 90% for Au and 90% for Cu.
5. Metal prices; $1300/oz Au and $2.40/lb Cu
6. Overall slope angles; 200 overburden, 420 saprolite, and 440 in rock.
WSP ‘s resource estimate for Primavera is based on drill core assay results from a total of 33 holes totaling 13,491 metres of drilling and 52 trenches totaling 660.9 metres. Statistical and geostatistical analysis was completed on the total database to assess the characteristics and distribution of gold, copper and silver values across the deposit. Variograms were generated for gold, copper and silver and search parameters established for grade interpolation using kriging.
Additional Resources; Calibre Mining Corp. has outlined additional Inferred resources in three deposits; Cerro Aeropuerto, Riscos de Oro, and La Luna.
In February 2011, Calibre announced two new gold and silver resources for the 100% owned Cerro Aeropuerto and La Luna deposits. The National Instrument 43-101 (“NI 43-101”) compliant, inferred resource totals 835,450 ounces of gold and 4,288,070 ounces of silver (903,000 ounces of gold equivalent).
Calibre announced its third gold and silver 43-101 Inferred resource on the 100% owned Riscos de Oro deposit in September 2012. The new inferred resource totals 222,300 ounces of gold and 4,142,000 ounces of silver (287,100 ounces of gold equivalent).
Calibre’s three National Instrument 43-101 (“NI 43-101”) compliant inferred resources total 1,057,750 ounces of gold and 8,430,070 ounces of silver (1,190,000 ounces of gold equivalent). The inferred resources were compiled by Wardrop a Tetra Tech company (“Wardrop”).
Inferred Resource for Cerro Aeropuerto, La Luna & Riscos de Oro (using a 0.6 g/t AuEq cutoff grade)
|Riscos de Oro||2,159,000||3.20||59.67||4.14||222,300||4,142,000||287,000|
1. Resource models used Inverse Distance grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids and a base cutoff grade of 0.6 g/t.
2. Resource Estimates for La Luna and Cerro Aeropuerto detailed in Technical Report titled NI 43-101 Technical Report and Resource Estimation of the Cerro Aeropuerto and La Luna Deposits, Borosi Concessions, Nicaragua by Todd McCracken, dated April 11, 2011.
3. Gold Equivalent (AuEq) for Riscos de Oro was 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%.
4. Gold Equivalent (AuEq) for La Luna and C. Aeropuerto was calculated using $1058/oz Au for gold and $16.75/oz Ag for silver, and metallurgical recoveries and net smelter returns are assumed to be 100%.
The Cerro Aeropuerto resource is contained within the Siuna Project currently optioned to Centerra Gold. The Riscos de Oro and la Luna deposits are contained within the Eastern Borosi Project currently in IAMGOLD JV.
Rosita D JV (33% Calibre) Resources; Additional resources exists on the Rosita D Joint Venture which is owned 33% by Calibre Mining and 67 % by Rosita Mining.
In February 2016 the Rosita D Resource Update included; Stockpile resources upgraded to Indicated category, Total gold and copper resources increased from the 2012 estimate by 24% and 8% respectively, and the maiden tailings resources estimated.
The resource estimate in stockpiles totals 70.9 million lbs. of copper and 96,660 oz. of gold and 46.2 million lbs. of copper and 50,330 oz. of gold in the Indicated and Inferred categories respectively. Indicated resources total 6.46 million tonnes grading 0.47 grams gold per tonne and 0.5% copper per tonne whilst Inferred resources total 3.44 million tonnes grading 0.46 grams gold per tonne and 0.61% copper per tonne in a series of stockpiles located near the former producing Santa Rita gold-copper open pit mine. These estimates have been based on a US$10 net smelter return (“NSR”) cut off. In addition, the Company is also reporting maiden Inferred resources of 1.96 million tonnes grading 0.56 grams gold per tonne at cut-off of 0.3 g/t gold in tailings located proximal to the Santa Rita stockpiles.
The results of these resource estimates, which are summarized in Table below, were prepared by Yungang Wu., P. Geo., an independent Qualified Person as defined by NI 43-101.
Table- Indicated and Inferred Mineral Resource Estimate, Santa Rita Stockpiles and Tailings
|ZONE||Class||AuEq g/t||Au Eq oz|
1. 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.
2. A gold price of US$1,200/oz, copper price of US$2.5/lb and silver price of US$16/oz were utilized in the NSR calculations of block values with process recoveries of 80% for gold, 35% for Cu (10% deducted for smelting) and 65% for silver. These values were equated against a cut-off grade of US$10 for stockpiles and 0.3 g/t Au for tailing mineral resources.
3. For the cut-off grade, mining costs were assumed at US$1.00/t, process costs at US$7.50/t and G&A costs at US$1.50/t
The updated NI 43-101 resource estimates incorporated the results of a reverse circulation drilling campaign completed by Rosita in the fourth quarter of 2015. This work included 1,040 m of drilling in 55 vertical in-fill holes on five stockpiles located near the former Santa Rita open pit and 87 auger holes totaling 460 metres in a portion of the tailings piles, drilled in 2012 and 2013. Drilling to test the tailings only tested a small portion of the overall tailing piles which remain open for possible resource expansion
The stockpiles at the project were generated over a 17-year operating life from 1959 to 1975 at the Santa Rita open pit mine. A total of 5.4 million tonnes averaging 2.06% copper, 0.93 grams gold and 15.08 grams silver per tonne were mined. In addition to the stockpile resources, the concessions also include 15 exploration targets for gold-copper skarn and porphyry mineralization.
Notes (for all Resource Estimates):
- CIM definition standards were followed for the resource estimate.
- Numbers may not add exactly due to rounding.
- Mineral Resources that are not mineral reserves do not have economic viability
- 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.
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.