Information on this website of a technical or scientific nature is reviewed and approved by Andrew Swarthout, AIPG Certified Professional Geologist, who is the Chairman 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.
he 2017 Corani Technical Report was prepared by a team of independent Qualified Persons (or “QP”s, as defined in National Instrument 43-101) including: Juan Carlos Tapia, ChE, IMCh, PE of Sedgman, responsible for Summary, Introduction, Reliance on Other Experts, Recovery Methods, Interpretations and Conclusions, Recommendations and References; Kevin Gunesch, PE, Principal Mining Engineer of GRE, responsible for Property Description and Location, Accessibility and Infrastructure, History, Mining Methods and Market Studies; Jennifer Brown, PG, SME-RM, an associate of GRE, responsible for Geological Setting and Mineralization, Deposit Types, Exploration, Drilling, Sample Preparation and Analysis, Data Verification and Adjacent Properties; Rick Moritz, MMSA, Principal Mining Engineer of GRE, jointly responsible for Mineral Processing and Metallurgical Testing; Deepak Malhotra, PhD, MMSA, Independent Consultant, jointly responsible for Mineral Processing and Metallurgical Testing; Terre Lane, MMSA, Principal Mining Engineer of GRE, responsible for Mineral Resource Estimates, Economic Analysis, Other Relevant Data and Information and jointly responsible for Mineral Reserve Estimates and Mining Methods; Denys Parra, PE, Independent Consultant, jointly responsible for Mineral Reserve Estimates, Environmental Studies, Permitting and Social or Community Impact and Mining Methods; Gregory Wortman, BE (Metallurgy), PE, of Sedgman, jointly responsible for Project Infrastructure; Larry Breckenridge, PE, Principal Environmental Engineer of GRE, jointly responsible for Environmental Studies, Permitting and Social or Community Impact and Project Infrastructure; and, Michal Short, BE (Civil), CEng FIMMM, FAusIMM(CP), FIEAust, CPEng, of GBM, responsible for Capital and Operating Costs.
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.