Evolution Mining FY24 Guidance Update
SECTION 1 - SAMPLING TECHNIQUES AND DATA
Criteria
Sub-sampling
techniques
and sample
preparation
Quality of
assay data
and
laboratory
tests
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Cowal Section 2 Reporting of Exploration Results
Commentary
Resource Definition diamond core is cut with a diamond saw or chisel and the remaining core retained. Core is cut to preserve the bottom of hole orientation line. Diamond
core from infill drilling is submitted for analysis as whole core
In some instances, if unexpected or anomalous assays are returned, an additional quarter core may be submitted for assay.
In 2003 Analytical Solutions Ltd conducted a Review of Sample Preparation, Assay and Quality Control Procedures for Cowal Gold Project. This study, combined with
respective operating company policy and standards (North Ltd, Homestake, Barrick and Evolution) formed the framework for the sampling, assaying and QAQC protocols
used at Cowal to ensure appropriate and representative sampling.
Sample preparation of diamond core samples is undertaken by external laboratories according to sample preparation and assaying protocols established to maximise the
representation of the Cowal mineralization. Laboratories' performance is monitored as part of Cowal's QAQC procedure. Laboratory inspections are undertaken to monitor
compliance to Cowal sampling and sample preparation protocol.
Sample preparation was conducted by SGS West Wyalong, OSLS Bendigo and ALS Orange. Sample preparation consisted of:
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Drying in the oven at 105°C; crushing in a jaw crusher;
Fine crushing in a Boyd crusher to 2-3mm; with SGS and ALS rotary splitting a 3kg assay sub-sample if the sample is too large for the LM5 mill, and OSLS rotary
splitting a 500g charge;
SGS and ALS Pulverising in the LM5 mill to nominal; 90% passing 75 μm; and
a 50g fire assay charge taken with an atomic absorption (AA) finish for SGS and ALS, and a 500g photon assay charge of fine crushed sample for OSLS.
Cu is assayed for using ICP techniques.
Quality control procedures adopted to maximise sample representation for all sub-sampling stages include the collection of field and laboratory duplicates and the insertion of
certified reference material as assay standards (1 in 20) and the insertion of blank samples (1 in 35) or at the geologist's discretion. Coarse blank material is routinely
submitted for assay and is inserted into each mineralised zone and sample identified as containing visible gold where possible. The quality control performance is monitored
as part of Cowal QAQC procedure.
SGS West Wyalong and OSLS Bendigo act as Primary Laboratories and ALS Orange conducts independent Umpire checks and primary assaying during periods of high
sample volume. All labs operate to international standards and procedures and take part in the Geostatistical Round Robin inter-laboratory test surveys. The Cowal QA/QC
program comprises blanks, Certified Reference Material (CRM), inter-laboratory duplicate checks, and grind checks. Both the SGS and ALS laboratories analyse for Au
utilizing Fire Assay with an AAS detection, with the OSLS laboratory analysing for Au utilizing Photon Assay.
Typical protocols for QAQC checks are summarised below, however depending on sample submission batch sizes overall rates may vary slightly:
1:30 fine crush residue has an assay duplicate.
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1:20 pulp residue has an assay duplicate.
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1:20 wet screen grind checks
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1:35 site blanks are inserted into the dispatch ensuring at least 1 blank per fire
1:20 CRMS submitted in the dispatch
The frequency of repeat assays is set at 1 in 30 samples.
All sample numbers, including standards and duplicates, are pre-assigned by a QA/QC Administrator and given to the sampler on a sample sheet. The QA/QC Administrator
monitors the assay results for non-compliance and requests action when necessary. Batches with CRM's that return assays outside the ±2SD acceptance criteria from the
CRM mean are reviewed and re-assayed if definitive bias is determined or re-assay will make a material difference.
Material used for blanks is uncertified, sourced locally, comprising local basalt which has been determined to be below detection limit. Results are reviewed by the QA/QC
Administrator upon receipt for non-compliances. Any assay value greater than 0.1g/t Au will result in a notice to the laboratory.
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