Fire Assay — Gold (AAS Finish)
Industry-standard gold analysis utilizing 30g/50g lead collection fire assay fusion followed by cupellation, acid digestion, and Flame AAS finish for exploration drill cores, rock chips, and trench samples.
Analytical Overview & Methodology
Our Fire Assay Gold with AAS Finish (FA-AAS-01) represents the international exploration benchmark for gold determination in drill cores, reverse circulation (RC) cuttings, rock chips, and channel samples. Operating under strict ISO/IEC 17025 principles, RVA Laboratories delivers sub-part-per-million accuracy across complex geological formations in Tanzania and the wider East African Greenstone belts.
Methodology & Workflow
A representative 30g or 50g charge is mixed with customized flux formulations designed specifically for African geological matrices (silicate, carbonate, or pyritic ores). The mixture is fused at 1,050°C in heavy-duty gas-fired fusion furnaces where molten lead captures all gold and precious metals. The resulting lead button is cupelled at 950°C in porous magnesium oxide cupels, oxidizing lead and leaving a high-purity silver-gold prill.
The prill is digested in concentrated aqua regia on precision graphite digestion blocks and aspirated into our calibrated Flame Atomic Absorption Spectrometers. Dual-beam optics and background correction eliminate spectral interferences, delivering reliable gold detection down to 0.01 ppm.
| Method Code | FA-AAS-01 |
|---|---|
| Element Coverage | Gold (Au) |
| Detection Range | 0.01 – 100.0 ppm Au (g/t) |
| Sample Requirement | 30g to 50g pulverized pulp (85% passing 75µm) |
| Instrumentation | High-Temperature Fusion Furnace + Flame Atomic Absorption Spectrometer (FAAS) |
| Standard Turnaround | Standard: 3-5 Working Days | Fast-Track Rush: 24-48 Hours |
Laboratory Protocols & Execution Specs
- Sample Charge: 30g or 50g pulverized sample pulp
- Collection Method: Lead collection fire assay with optimized borax-silica-litharge flux
- Digestion: Cupellation to silver prill followed by aqua regia dissolution
- Analytical Finish: Atomic Absorption Spectroscopy (AAS) with deuterium background correction
- Target Matrix: Exploration drill cores, RC chips, trench samples, low-to-medium grade gold ores
- QA/QC Protocols: 1 CRM, 1 blank, and 1 duplicate per 20-sample tray rack
JORC & NI 43-101 Data Integrity Guarantee
Every batch tested under method FA-AAS-01 includes matrix-matched Certified Reference Materials (CRMs), analytical blanks, and duplicate splits at a minimum 20% insertion rate. Official digital Certificates of Analysis are digitally signed and traceable.