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7 <br />problems exist with the WAD cyanide method. Total meta] concentrations are within 10% <br />of dissolved metal concentrations with the exception of calcium and 'trop values. The <br />calcium concentration in the un5ltered sample was "20% greater (on a relative percent <br />difference basis -RPD = (~A-B~(A+B))x200%) than in the filtered sample. This may be <br />due to visible precipitation of gypsum (CaSO42H20) in the upper tailings pond, which is <br />more concentrated in most constituents than the lower tailings pond. The higher iron <br />concentration in the unfiltered sample again indicates that colloidal iron is present in the <br />upper tailings pond. <br />Collection Pond. The collection pond has the highest cyanide concentrations. The quality <br />control duplicate analysis results for cyanide are quite poor. According to TR-006, duplicate <br />samples must agree within t the detection limit if the analyzed value is s 5 times the <br />method detection limit and within s 20% RPD if the analyzed value is > 5 times the method <br />detection limit (Appendix A). The total cyanide duplicate values for the filtered samples are <br />±70% RPD. For WAD cyanide the duplicate values for both filtered and unfiltered samples <br />are unacceptable: for unfiltered samples the duplicates are ±114% RPD and for filtered <br />samples they are within ±38% RPD. The duplicate analyses for the other constituents in <br />both the filtered and unfiltered samples are within 10% RPD except for total copper <br />(±12.2% RPD) and total sodium (±17.9% RPD). <br />3.13 Groundwater Samples <br />Groundwater Wells. As discussed above, no groundwater wells were able to be sampled <br />because the groundwater pump was not operational. <br />3.1.4 Quality Conttrol Samples <br />Field and Rinse Blank. The field blank and rinse blank used second-stage DII water from <br />the BMRI laboratory and had lower concentrations of iron, zinc, calcium and sodium than <br />the DI water used for the first third-party sampling. The rinse blank had comparable <br />concentrations of constituents to the field blank except for sodium, which was somewhat <br />higher in the rinse blank. Samples were collected for nitrate+nitrite, but analyses were not <br />performed because cyanide was not expected to be detected in these samples. <br />3.2 FILTERED VS. DISSOLVED CONCENTRATIONS IN PROCESS POINT <br />SAMPLES <br />In this and the following third-party sampling trip both filtered and unfiltered samples were <br />and will be collected to determine (1) if there are significant differences between total and <br />dissolved metal concentrations, and (2) if filtered and total ryanide concentnations differ <br />RCG/Hagler, Bailly, Inc <br />