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iii iiiiiiiiiiiuiii <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sher man St., Room 215 <br />Denver, CO 80203 <br />Phone: 0031 ilGG-35G7 <br />FAX: 13071 83?-B I OG <br />DATE: February 11, 1993 <br />T0: Bruce Humphries <br />FROM: Larry Oehler ~~~ <br />lip` <br />- <br />RE: High Cadmium Analyses, Battle Mountain Gold Company, San Luis <br />Project, File No. M-88-112 <br />of cow <br />~~~~ a <br />:. ~~~ <br />tev~ <br />Rov Romer <br />Governor <br />A1ichael B. Lung <br />Drvrsion Dnector <br />Analyses of water samples at Battle Mountain Gold Company's San Luis Project for <br />dates prior to and including the November 11-12, 1992 biweekly sampling event show <br />high dissolved cadmium readings. <br />The analyses showing high cadmium are probably the result of contamination of <br />sampling equipment and subsequently water samples. Dr. Harry Posey and Alana Scott, <br />Environmental Engineer for BMG, consider the use of cadmium nitrate used to <br />precipitate sulfides out of process water samples to be the most promable source of <br />contamination. According to Ms. Scott, cadmium nitrate was used to treat process <br />water samples in the same filter apparatus used to filter ground and surface water <br />samples analyzed for dissolved metals. It is believed that cadmium forbed onto the <br />filter apparatus, which is acrylic plastic, and desorbed during subs@quent sampling <br />events. This idea is being investigated. <br />The filter apparatus was washed in accordance with procedures in the permit; <br />however, cadmium is released as a result of a solution chemistry profess rather than <br />by washing and rinsing. Except for two samples taken on September 4 and 16, 1992 <br />that appear to be recording errors unfiltered samples taken at the same locations <br />and times show total cadmium to be below the detection limit. This meinforces the <br />belief that the dissolved cadmium resulted from contamination of the filter <br />apparatus. <br />Battle Mountain Gold discontinued the use of cadmium nitrate after their <br />November 11-12, 1992 sampling event and preliminary analyses of their <br />November 23-25, 1992 samples show no cadmium above detection limits. Also, <br />Ann Maest competed a third party monitor sampling on the same dates and her report <br />shows total cadmium to be below the detection limit. <br />A BMG biweekly sampling event occurred in late January. All locations that have <br />shown high dissolved cadmium analyses were sampled and are being analyzed on a rush <br />basis. The results should be available soon. <br />I will continue to monitor this matter. <br />/ern <br />cc: Ken Kluksdahl <br />Anne Baldrige <br />Alana Scott - <br />Dean Massey - <br />Maclovio Mart <br />Helen Sigmund <br />Nora Jacquez <br />- BMG <br />- BMG <br />BMG <br />BMG <br />Inez - CCCD <br />- CCCD <br />- CCCD <br />Maria Valdez - PAEC <br />Roger Flynn - PAEC <br />Jane I. Kircher <br />Jim Pendleton - DMG <br />Harry Posey - DMG <br />Jim Stevens - DMG <br />6188E <br />