The Sampling Process

The sampling process begins with the selection of a representative sample of the deposit, which is then processed to remove any contaminants and to prepare it for analysis. This can involve crushing, grinding, and pulverizing the sample, depending on the mineral being analyzed. The prepared sample is then analyzed to determine its chemical composition and other properties, such as size, shape, and mineral content.

Quality Assurance and Quality Control

Quality assurance and quality control are essential components of the sampling process, as they help to ensure the accuracy and reliability of the results. QA/QC involves a series of checks and balances throughout the sampling process, from the selection of the sample to the final analysis. The goal of QA/QC is to identify and correct any sources of error or bias in the process, and to provide a high level of confidence in the results.

After a few high profile mining/exploration scams (Bre-X) the Canadian government, and many others have followed suit, demand a higher caliber and standards for reporting sample data. This falls under what is known as NI 43-101 whereby a qualified geoscientist (Professional Geoscientist) must review all aspects of the sampling procedures for accuracy and potential issues.

In addition to strict sample/rock handling guidelines developed by the geologist/engineer to minimize contamination at the exploration site, there are specific methods to verify and increase the validity of sample data at the lab level.

Blanks

Blanks are material which is guranteed not to contain any of the mineral being assayed for. This will determine if potential contamination at the lab setting is taking place. If a known non-mineralized sample shows a positive result to a mineral – a red flag is raised. Blanks are usually purchased from labs, or simple ground up glass will suffice.

Standards

Standards or samples purchased from labs, which have a known grade of mineral to be tested for. They can be high, low or even median grade standards. The purpose of the standards are to test for calibration errors at the lab level. Proper procedure is to have standards of varying grades to best represent close to expected grades in the samples being tested. A standard which is returned with a value outside the accepted range (given by standard source lab) could indicate poor mixing of the sample, or an calibration error of the equipment/personell handling the samples.

Duplicates

Duplicates are taken in two different phases. Core duplicates are a secondary splitting of core resulting in two samples that in theory should be similar in grade. The second, usually done as internal tests in the lab is to retest a sample already tested, again the samples should in theory be similar. A rule of thumb is that all samples above a certain grade are automatically re-sampled for verification. Under regulations some core must remain and be stored for future verification if need be.

If core duplicates at the exploration phase differ by a large amount it could indicate contamination or improper sampling procedures. There is variance in precious metal samples is to nugget effect and can show up in assays.

If lab duplicates come back with variance, it may indicate mixing, procedure or calibration errors. Precious metal duplicates can vary due to the nugget effect. Any company can request any sample to be retested -sometimes by another lab for verification of assays.

It is common practice that all samples above a certain grade be verified by another independent lab.