PAL1000 method for gold assay
- Representative – Large assay sample size up to 1000 g to minimize nugget effect
- Fast – Even 1-2 days turnaround time for rush orders and 1-3 weeks for regular orders
- Quality – Accurate method for cyanide leachable gold
- Economical – Typically lower total cost than in fire assay
CRS Laboratories offers gold assays for geological samples with PAL1000 method. The method is capable of analysing very large samples up to 1 kg, which improves the representativeness of the assay results and minimizes the gold nugget effect.
The PAL1000 machine contains steel pots, in which the samples are completely pulverized (typically to better than 90% < 75µm) with steel balls and simultaneously leached with cyanide (using Assay Tabs). The solution is analyzed for gold by FAAS. For lower detection limit solvent extraction is used in addition. The quality control of the analysis includes certified reference materials, blank samples and duplicates for every leach batch.
The cyanide leaching waste is treated on-site in our waste water purification process in which the cyanide is destroyed. The waste water treatment process consist of chemical reactions, flocculation and ion exchange. The resulting process water is nontoxic and is allowed to be disposed to sewer.
The PAL1000 method measures only the cyanide leachable gold, so refractory gold is not assayed. Also graphite (by preg-robbing) and high sulphide (tens of percents) may lower the recovery of the gold in the cyanide leaching. We recommend residual gold testing for PAL1000 when samples from any new mineralization are requested for analysis. However, we have several gold mines and exploration companies in Finland and Sweden as our customers, and their recoveries have been 95-100 % gold in the cyanide leaching. The recovery is measured by first leaching the sample with the PAL1000 cyanide leach, and then the leaching residue is analyzed by fire assay for non-cyanide leachable gold.
We can customise the PAL1000 service package to meet the customer’s requirements. We have fast turnaround times and the report delivery times can be scheduled in advance. The sample size for analysis can be varied between 100-1000 g and detection limit can be lowered with additional solvent extraction if needed. We also offer various other sample preparation and analysis services to supplement the PAL1000 assay.
Contact us for more information and quote. We will be happy to serve!