Great Bear has implemented a systematic and rigorous quality assurance/quality control (QAQC) procedures for all drill programs and surface sampling programs to ensure best practices in handling of all samples and disclosure of results.
The technical information on this website pertaining to geological, geochemical and geophysical interpretation, as well as gold assay results, has been reviewed and approved by R. Bob Singh, P.Geo and Andrea Diakow, P.Geo, both Qualified Persons as such term is defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects.
All QA/QC procedures below have undergone an independent third-party review from Lynda Bloom, P.Geo of Analytical Solutions Ltd.
QA/QC Procedures – Diamond Core Samples
Drill core is brought to the core logging facility (Red Lake) and is then geotechnically logged: orientation marks measured, magnetic susceptibility, and specific gravity values are recorded by the geotechnician. All data is recorded electronically on a tablet. The orientation lines are preserved in the cut core. Core is cut a along a line established at a consistent spacing to the orientation line to ensure the same half of the core is consistently being submitted for analysis. Where the orientation line is not available, a continuous cut line is drawn perpendicular to fabric.
The drill core is logged by a geologist who then lays out sample intervals varying from 0.3 to 1.5 meters in length. Samples with visible gold are marked on the sample tag with a red line through the bar code. Upon completion, the core is sawn in half on-site, with one side bagged and labelled; the remaining half is placed in core boxes to serve as a permanent record and stored in core racks on site. Core sawing equipment is cleaned between samples; water and abrasives are used to clean the blade.
Core Sample Insertion
Quality control insertion rates are a minimum of 10% of the total sample volume with either a lab certified gold or blank standard inserted every 10 samples. Gold standards that have been selected include low (~1 g/t Au), medium (3-5g/t Au) and high (>10 g/t Au) grade. The high-grade gold standard is selected to test the gravimetric analysis stream conducted on all gold samples greater than 10 g/t Au. The tolerable limits are values returned which are within the certified known standard deviations of the quality control material.
Sample Preparation & Shipping
Bagged and labelled rock samples are combined with the associated quality control samples, packaged in crates, fastened with a security tag, and shipped to Activation Laboratories Ltd. (independent lab with ISO/IEC 17025 accreditation) for analysis using a bonded courier. A rigorous chain of custody is established between the company, the commercial trucking company and the laboratory.
Samples received by the lab are logged, weighed and assigned into batches. Sample preparation begins with crushing samples to 80% passing 2mm. From this sample, 250 grams of material is separated out using a riffle splitter which is then further pulverized to at least 95% -105 microns resulting in a pulp that is ready for analysis. When the lab encounters samples with visible gold (red line through bar code) an additional round of cleaning procedures is performed between samples to mitigate the risk of cross contamination. The remainder of the sample is re-sealed in its original bag until it is eventually returned to Great Bear. Analysis on the pulp includes fire assay with AA finish and ICP with near total 4-Acid digestion. Samples that assay greater that 10 g/t gold in fire assay undergo a 50-gram gravimetric finish.
Upon receiving assay results from the lab, quality control samples are queried from the database to ensure they fall within the tolerable limits established by the certification of the quality control material. Quality control samples that fall outside the tolerable limits are flagged for investigation. If it is determined that the outlier is a result of inaccuracy in the assaying process, the quality control sample and additional shoulder samples are submitted for re-assay. The investigation is completed once the re-assays results are within tolerable ranges on both the quality control sample and the shoulder samples. This QAQC work is completed prior to disclosing results.
Field Duplicated and Check Assays
A field duplicate study using the analysis of ¼ split core was conducted from 2017 to 2020. Samples were selected at random every 40-60 samples, the ¼ cut sample size was used to ensure the other half of the core was still retained. Results from this work showed reliable duplication of gold results in significant population of the dataset. This procedure was discontinued in 2020 in favor of checking pulp and reject duplicates at a second laboratory.
Pulp material is being submitted as check assay to a separate ISO/IEC 17025 accredited lab on a quarterly basis, selected to represent 1% of all low grade material and 1.5% of material greater than 1 g/t. General repeatability of these samples is assessed to identify potential lab inaccuracy or biasing. To date no concerns have been noted from this work.
All reject and pulp materials from samples are returned from the laboratory to the Company and stored securely on site. Cut drill core is also stored securely on site.
Methodology for Calculations Composite Intervals
Calculated gold composites in the LP Fault Zone use a minimum grade of 0.10 g/t gold, un-capped assays and contain no more than three metres of internal dilution with zero grade.
Composited intervals adhere to strict geological zones by observing major lithological formations and staying within distinct mineralization styles.
Drilling Width versus True Width
Where possible, best efforts are made to calculate true widths of zones. In established vein zones such as the Hinge Zone and Limb Zone, true widths are calculated by intersecting the drillhole intercept with the vein geometry. These values range from 75 – 95% of true width and are reported on a hole by hole basis.
True widths on the LP Fault Zone are undetermined due to the complex nature of anastomosing mineralized corridors, zone dip, drill direction and lower cut-off grades. The company is working towards establishing accurate 3D models to assist with establishing true widths for LP drillhole intercepts.
Hinge and limb zone data collected up to December of 2019 are included in the 43-101 technical report document dated March 23, 2020:
Great Bear includes 100% of its drilling results in its news releases. Since December of 2019, the core focus of drilling has been on the LP Zone and hole locations and results are posted its website at:
This information includes reported gold intervals, drill hole locations, azimuths and dips which allow any investor to reconstruct all publicly released data.