The Stibnite Advisory Council’s Independent Water Monitoring Program reported consistent results between its ground and surface water data and that of Perpetua Resources in its third year of testing.
This one-page summary presents the results from an interlaboratory comparison between two analytic laboratories (SVL Analytical Inc., Kellogg, Idaho and Anatek Labs, Inc., Moscow, Idaho) that tested concentrations of water quality analytes from waters collected at the Stibnite Gold Project site in 2023.
Methods: Surface and groundwater samples were collected from 9 sites plus 2 for quality control on August 8 and July 18, 2023, respectively. A total of 25 water quality parameters were evaluated for each of the 11 samples resulting in a total of 275 sample-analyte combinations per sampling event. Collection occurred via split sampling — the separation of a water sample into two parts such that each part was representative of the original sample — with each sample independently analyzed by Anatek Labs (Moscow, ID) and SVL Analytical (Kellogg, ID).
Results: Results of the 275 surface water analysis comparisons indicated that 95.3% (n=262) were acceptable and 4.7% (n=13) were flagged. Results of the 275 comparisons of groundwater analyte concentrations indicated that 97.5% (n=268) were acceptable and 2.5% (n=7) were flagged. Most flagged values were for very low concentrations close to the method detection limits.
Conclusions: Based on the results of surface and ground water comparisons in 2023, two primary conclusions can be drawn: 1) there was strong interlaboratory agreement in both surface and groundwater results between Anatek and SVL laboratories; 2) there was no consistent site-specific or analyte differences between laboratories other than slightly higher (~1 part per trillion) mercury concentrations reported by SVL, mostly at extremely low concentrations. For more information, please contact Dr. Timothy Link (tlink@uidaho.edu) with the University of Idaho’s College of Natural Resources.