Read the sample identifiers, reporting basis and analytical method together. A laboratory result applies to the submitted sample; its relevance to the shipment depends on how that sample was collected.
An assay report records the results obtained from a submitted sample. To use it in a purchase decision, you need to know what was sampled, how the laboratory tested it and whether the results address the receiving plant’s requirements.
Read the complete report before transferring a grade into a price comparison. The sample description, units and method notes may change how that number should be interpreted.
Begin with the report’s identity
Check the laboratory name, report number, issue date, client name and sample identifiers. Obtain the complete report, including notes and continuation pages. A cropped screenshot can omit qualifications that matter to interpretation.
Where the decision warrants it, contact the laboratory through independently obtained contact details to ask about its report-verification process. Do not assume a phone number added to a forwarded image belongs to the laboratory. Confirm what the laboratory can disclose and who is authorised to request it.
Read the units and reporting basis
Percent, parts per million and grams per tonne are not interchangeable labels. Neither are an element and its oxide. A lithium result expressed as Li is different from one expressed as Li₂O; the reporting basis needs to be explicit before comparing offers.
Also check whether a value is reported on a dry basis and how moisture was established. Write the units beside every number you transfer into your buying model. That small discipline helps prevent comparisons between unlike quantities.
Ask whether the method suits the question
A laboratory’s accreditation and the scope of an individual method are separate things to examine. ISO/IEC 17025 addresses the competence, impartiality and consistent operation of testing and calibration laboratories. It is not an accreditation of the mineral seller or a certification of an entire shipment. [1]
Ask the laboratory or an independent technical adviser whether the method is suitable for the sample matrix, target analytes and concentration range. Review detection limits, preparation procedures and any qualifications. Do not use a field-screening result as a final settlement assay unless the parties have specifically agreed an appropriate procedure.
Trace the sample back to the lot
Was the sample taken from one rock, one bag, several increments or a defined stockpile? Who selected it? Could the sampling favour higher-grade pieces? Was the material subsequently blended, moved or replaced?
SGS’s sampling guidance emphasises obtaining representative material for analysis. For a buyer, the commercial implication is to agree a defensible collection and preparation procedure for the actual lot, rather than relying on an attractive specimen. [2]
Look beyond the payable component
A receiver may care about contaminants, particle size and process compatibility as much as the target metal. Ask the receiver which limits are absolute rejection thresholds and which lead to a price adjustment. Do not invent impurity thresholds from a report that was prepared for a different purpose.
An assay does not itself establish processing recovery. Where recovery is important, request suitable metallurgical work and an explanation of how representative that work is. Material with an appealing grade can still be a poor match for a particular plant.
Resolve disagreement before settlement
Decide how duplicate samples will be retained, how analytical differences will be handled and when an independent umpire result will apply. Name the relevant laboratory-selection process and the party paying for each step. Those terms are easier to negotiate before a dispute has financial consequences.
Record the review in a short note: identify the report, the lot it is said to represent, the checks completed and the questions referred to the laboratory or technical adviser. Attach that note to the offer so that the purchasing decision carries the qualifications as well as the reported grade.
References
The linked sources support the referenced information. Checklists and review questions are ECG’s editorial suggestions. This article provides general information, not advice on a particular transaction. External references do not imply an affiliation or endorsement.
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