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<br />A 5 C I <br />' 2. APPROACH <br />' In order to eliminate as much variability as possible from the database, the following <br />approach to sampling and analysis was taken: <br />' all samples were taken in a manner consistent with the sampling and handling <br />protocols described in the John C. Halepaska report of May 1992, already <br />' submitted to CMLRB by BMRC; <br />specifically, samples were tested and treated for potential sulphide <br />interference at the time of sampling, {by the addition of cadmium nitrate), <br />prior to preservation to pH 12 with sodium hydroxide to prevent cyanide <br />volatilization. Samples were rechecked for sulphide species on receipt by the <br />' laboratory. <br />' • samples were treated for potential nitrate interference in the Cyanide analysis <br />with sulphamic acid by Laboratory "C", (see data description below); <br />' • the same samples were split and analyses were performed by two separate <br />laboratories; <br />• laboratories were requested to use specified methods of enalysis for all <br />parameters requested, to eliminate method variation. (This was not possible <br />' for total cyanide in the case of Laboratory "A", and Laboratory "A" chose to <br />use ion chromography for free cyanide analysis) <br />• both laboratories instituted full QA/OC procedures for the sartiples, including <br />replicate analyses and "spiking" of samples, to assess the potential for matrix <br />variation effects. <br /> <br /> <br /> <br /> <br />' 2 <br />