General CRM FAQs - FAQS - AMIS - African Mineral Standards


What are CRM's

CRM's are samples with known grades used in quality assurance programs to help check assay results, especially laboratory bias and precision. They form an essential part of sample quality assurance programs and are an essential part of the mineral resource audit trail in bankable feasibility studies.

What’s the difference between an RM (reference material), a CRM (certified reference material) and QCM (quality control material)?

RM (Reference Material) is material, sufficiently homogeneous and stable with respect to one or more specified properties, which has been established to be fit for its intended use in a measurement process.

CRM (Certified Reference Material) is a reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that states the value of the specified property, its associated uncertainty, and a statement of metrological traceability.

QCM (Quality Control Material) is a material intended for internal laboratory quality control. A material or substance one or more of whose property values are sufficiently homogeneous, stable and well established to be used for maintaining or monitoring measurement processes. A QCM does not have formally assigned property values or uncertainties (ISO/CD Guide 80 - Guidance for in-house Production of Reference Materials for Metrological Quality Control (QCMs)).

What is a matrix reference material?

A matrix reference material is defined as a reference material that contains major, minor, and trace components. Matrix materials are intended to be used in conjunction with the analysis of real samples of the same or a similar matrix. They are normally materials that are sampled from nature ISO DGUIDE 30:2013(E) 2.4.

How will this CRM add value to my results?

It gives you faith in all of the other numbers. This CRM is quite simply a ruler you can use to measure the performance of your laboratory and to check the results the lab is reporting in an auditable way. It’s far easier to fix a problem in the lab than to fix a mineral resource or a mining problem or a metallurgical process.

Is it really necessary to use matrix reference materials?

It is global best practice for there to be a specific reference material for every type of sample sent to the laboratory.

The use of control samples that closely match the material being sampled will make life easier for the analyst and will result in fewer failed batches.

You may need to use the closest match available if there isn’t an exact match.

Synthetic gold standards may be an acceptable substitute for some ore types but they are really easy to get a good analysis from and they don’t really test the assayer.

What do you do if you have a lab quality problem? (besides blame the CRM)

AMIS Reference Materials are made so a single laboratory can compare their results with 15 to 30 other laboratories. If your laboratory is reporting quality sample results that fail your accept/reject QA rules (or Westgard Rules), or if you have just woken up to a >10% QC sample failure; quickly follow the Control Sample Failure Checklist in the Technical Information Section.

Note: complaints about the performance of CRM’s are rare and always taken seriously. They are fully investigated in accordance with internal company procedures and in accordance with the AMIS ISO 9001:2008 Certification.

AMIS will immediately replace CRM’s found to be faulty or which have been mislabelled.


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