ASSAY LAB
Overview
Temiskaming Testing Laboratories (TTL) Geochemistry Department offers a suite of assay/geochemical analytical services including but not limited to determination of precious metals (Au, Ag) by fire assay with instrumental and/or gravimetric finish. Further services will be added in the near future.
Sample Preparation
The preparation of a sample is the most critical facet in the analysis of geological materials.
It entails the crushing of all the sample, riffle splitting to obtain a sub-sample (typically, 250 g) that represents the entire sample followed by pulverization for subsequent analysis.
TTL maintains a stringent QA/QC protocol to ensure the integrity of the sample is not compromised. Jaw crushers and pulverizer bowls are frequently cleaned with barren material to bring sample contamination to the barest minimum. A portion of pulverized barren material is tested to monitor contamination and the remainder kept for future analysis if necessary. For every 20 samples, sample duplicate is created at the riffle splitting step and sample replicate created by taking an aliquot from the same pulp bag during the weighing process.
PRECIOUS METALS ANALYSES
Lead Collection Fire Assay with AAS/Gravimetric Finish
Classical fire assay using lead oxide-based flux is employed to separate and collect the precious metals from the sample matrix (gangue), followed by cupellation to separate the precious metals from lead. The silver bead/prill so obtained is digested with HNO3/HCl and subsequently analyzed by AAS. For gravimetric finish, the silver bead is digested with dilute HNO3, the Au is washed, dried, annealed and weighed.
FIRE ASSAY-AAS FINISH
| Code | Analyte | Detection Limit (µg/g) | Upper Limit (µg/g) | Sample Weight (g) |
|---|---|---|---|---|
| FA301-AA | Au | 0.005 | 10 | 30 |
FIRE ASSAY-GRAVIMETRIC FINISH
| Code | Analyte | Detection Limit (µg/g) | Upper Limit (µg/g) | Sample Weight (g) |
|---|---|---|---|---|
| FA301-GR | Au | 0.035 | - | 30 |
| FA303-GR | Ag | 3.50 | - | 30 |