Information on this website of a technical or scientific nature is reviewed and approved by Andrew Swarthout, AIPG Certified Professional Geologist, who is the President and CEO of the Company and a Qualified Person as defined in NI 43-101.
All diamond drilling has been performed using HQ diameter core with recoveries averaging greater than 95%. Core is logged and split on site under the supervision of Bear Creek geologists. Sampling is done on two-metre intervals and samples are transported by Company staff for direct shipping to ALS Chemex, Laboratories in Lima, Peru. ALS Chemex is an ISO 9001:2000-registered laboratory and is preparing for ISO 17025 certification. Silver, lead, and zinc assays utilize a multi-acid digestion with atomic absorption (“ore-grade assay method”). The QC/QA program includes the insertion every 20th sample of known standards prepared by SGS Laboratories, Inspectorate, Peru and Rock Labs, Australia.
The Corani Phase 1 Detailed Engineering work was conducted by GMI SA Ingenieros Consultores. GMI’s final Phase 1 Detailed Engineering report will be incorporated in the 2017 Corani Feasibility Study, which is being prepared by a team of independent engineering consultants and will be filed on SEDAR (www.sedar.com) by late October 2017. Kevin Gunesch, PE, Principal Mining Engineer of GRE, is the QP responsible for the Project Description and History, Market Studies and Mining Methods. Juan Carlos Tapia, ChE, IMCh is the QP for the Recovery Methods and Conclusions and Recommendations. Deepak Malhotra, PhD, MMSA, Independent Consultant, and Rick Moritz, Principal Mining Engineer of GRE are the QPs for Mineral Processing and Metallurgical Testing. Terre Lane, MMSA, Principal Mining Engineer of GRE, is the QP responsible for the Resource and Reserve Estimations and Economic Analysis. Larry Breckenridge, PE, Principal Environmental Engineer of GRE, is the QP for Environmental and Permitting and Social Community Impact sections. Denys Parra, PE, Independent Consultant, is the QP for responsible for Geotechnical studies. Jennifer Brown, PG, SME-RM, an associate of GRE, is the QP for Geological Setting and Mineralization, Exploration, Drilling and Data Verification sections of the study.
The 2015 Corani Feasibility Study was prepared by a team of independent engineering consultants. Daniel Neff, PE, of M3 acted as the Independent QP as defined by NI 43-101 and additionally is the QP responsible for the market studies, infrastructure, process plant capital and operating costs, economic analysis, conclusions and recommendations portions of the study. Tom Shouldice, PEng, independent consultant, is the QP for the metal recoveries and metallurgical testing sections. Rick Moritz, MMSA, Principal Mining and Process Engineer, of GRE is the QP for portions of the metallurgical analysis. Terre Lane, MMSA, Principal Mining Engineer, of GRE is the QP for the resource and reserve estimation and mining methods and mine capital and operating cost portions of the study. Laurie Tahija, MMSA, of M3 is the QP for the plant process engineering portion of the study. Chris Chapman, PE of GRE is the QP for the geotechnical, environmental, infrastructure, waste stockpile and tailings designs. Christian Rios, CPG, independent consultant, is the QP responsible for geology and mineralization, exploration, drilling, sample preparation, analyses and security, data verification, mineral resource estimates and adjacent properties.
The methods used in determining and reporting the Corani Project Mineral reserves and resources presented herein (derived from the 2015 Corani Feasibility Study) are consistent with the CIM Best Practices Guidelines. Numbers may not total due to rounding.
Assumptions used in the 2015 Corani Feasibility Study Mineral reserve estimate and economic analysis by GRE and M3 are:
- Silver Price=$20.00/oz.; Lead Price=$0.95/lb.; Zinc Price=$1.00/lb.
- Variable NSR cut-off values from $11/tonne to $23/tonne at different times in the production schedule to manage mill requirements and maximize project economics.
- Metallurgical testing of the Corani ore started in 2005 and over 500 batch floatation tests were completed since. The previous interpretation of test results was a classification of recovery performance into 4 “metallurgical types” from 9 mineralization ore codes applying an average recovery to each metallurgical type. These groups exhibited a large variation in flotation recovery. Recent analysis of metallurgical test work indicates that recovery is strongly related to the presence and/or absence of oxide minerals. Using advanced statistical methods (including classification cluster analysis and nonparametric regression analysis), zinc grade, mineralogy from geologic logs, and elevation were identified as good indicators of oxidation and as a result, good predictors of recovery. These parameters were used to develop statistical numerical models to much more accurately predict recovery. Validation testing shows the new model projections of recovery closely fit all available metallurgical test work data.
- The new recovery model was used for pit optimization, mine planning, and production scheduling. The overall result was approximately 8% increase in silver and zinc recovery and an 8% decrease in lead recovery from those cited in the 2011 Corani Feasibility Study.
The Mineral resource pit shell is a Whittle pit based on the following input assumptions:
- Silver Price=$30.00/oz.; Lead Price=$1.425/lb.; Zinc Price=$1.50/lb.
- Mixed oxide material that was not economic by flotation processing was not included in the Mineral reserves, however, this material is included in the Mineral resources.
- The Mineral resource cut-off was $9.49/tonne processing cost, plus $1.51 G&A cost which represents the internal process cut-off.
- The potentially leachable mixed oxide material that fell within the Mineral resource pit shell was included as a silver resource cut-off grade of 15g/tonne and block elevation above 4900 meters.
- Mineral resources are not Mineral reserves and do not have demonstrated economic viability.
All diamond drilling at Corani has been performed using HQ diameter core with recoveries averaging greater than 95%. Core is logged and split on site under the supervision of Bear Creek geologists. Sampling is done on two-meter intervals and samples are transported by Company staff to Juliaca, Peru for direct shipping to ALS Chemex, Laboratories in Lima, Peru. ALS Chemex is an ISO 9001:2000-registered laboratory and is preparing for ISO 17025 certification. Silver, lead, and zinc assays utilize a multi-acid digestion with atomic absorption (“ore-grade assay method”). The QC/QA program includes the insertion every 20th sample of known standards prepared by SGS Laboratories, Lima. A section in Bear Creek’s website is dedicated to sampling, assay and quality control procedures.
Total cash cost per ounce of silver is calculated in accordance with a standard approved by The Silver Institute, a nonprofit international association that draws its membership from across the breadth of the silver industry. Adoption of the standard is voluntary and the cost measures presented may not be comparable to other similarly titled measures of other companies. Total cash cost includes mine site operating costs such as mining, processing, administration, and treatment and refining charges, but is exclusive of amortization, reclamation, capital, exploration costs and taxes on income. Total cash costs are reduced by lead and zinc by-product revenues, and then divided by silver ounces sold to arrive at total cash cost of per ounce of silver, net of by-product revenues.
The Company has elected to follow the Silver Institute’s cash cost standard, and has therefore excluded reclamation costs from its calculation of total cash cost per ounce of silver.