Between the pulp and the reported gold grade there are nine or so physical steps — weighing, flux addition, fusion, cupellation, prill handling, dissolution, the instrument finish, QA/QC review, approval. Sample identity has to survive all of them, usually at a rate of hundreds or thousands of samples a day. Paper trays and spreadsheets survive that rate only until the first mixed-up rack.
The worksheet is the backbone
In OnLIMS, the OnWSH electronic worksheet carries the fire assay run. Layout templates group samples with their certified reference materials, blanks and duplicates in furnace sequence, so physical position — not handwriting — is what carries identity through the process:
- Weighing capture Pulp and flux weights land in the worksheet directly from analytical balances — including fire assay balances with auto-tare — with no manual transcription.
- Furnace sequence held The worksheet preserves the fusion and cupellation order, so the prill that comes out of position 14 is the sample that went into position 14.
- Instrument finish mapped AAS or ICP-OES/MS results are captured through serial or file interfaces and mapped automatically onto worksheet positions.
- Electronic locking Two chemists cannot silently overwrite the same worksheet; edits are controlled and recorded field by field — old value, new value, user, timestamp.
- Bidirectional operation Where the instrument software accepts it, OnLIMS writes the sequence file — sample IDs and, where needed, weights — and then captures the instrument's own output.
QA/QC enforced in the run, not discovered after it
The expensive fire assay failure is the one found late: a whole batch approved before anyone notices the standard drifted or a blank came back contaminated. OnQC evaluates CRMs, blanks and duplicates as results arrive, using Shewhart, X-Control, CUSUM and Thompson-Howarth control charts with bias tracked against certified values. A 2SD deviation warns; a 3SD failure blocks sign-off until it is resolved and justified. The batch cannot ride through to the certificate with a failed standard on board.
What laboratory professionals say
“The ONLINE LIMS worksheet module is the best I have seen from all LIMS providers! Highly recommend the product.”
— Russ Calow, Analytical Laboratory Consultant · public comment on LinkedIn
Frequently asked questions
How does a fire assay sample keep its identity through fusion and cupellation?
The worksheet is the anchor. OnLIMS worksheet templates lay out samples, standards, blanks and duplicates in furnace sequence, so position — not handwriting — carries identity through weighing, fusion, cupellation and the instrument finish. Balance and instrument output maps onto worksheet positions automatically.
Can two chemists overwrite each other's fire assay worksheet?
No. Electronic locking controls prevent concurrent edits to the same worksheet, and every change is recorded in a field-level audit trail — old value, new value, user, timestamp. Results lock on publish under supervisor control.
What happens when a fire assay standard fails QA/QC?
OnQC evaluates CRMs, blanks and duplicates as results arrive, using Shewhart, X-Control, CUSUM and Thompson-Howarth charts. A 2SD deviation raises a warning; a 3SD failure blocks sign-off until the deviation is resolved and justified — so a failed standard cannot ride through to the certificate.
Related: Gold mine laboratory LIMS · QA/QC for mining labs · Instrument integration · Fire assay optimization (article)