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~ STATE OF COLORADO <br />MINED LAND RECLAMATION DIVISION of coo <br />Department of Natural Resources ~~`-~9g <br />Nr.~ v <br />1313 Sherman SL, Room 215 ~ . ~, „ ~ ~ <br />Denver, CO 80203 i L._~ , <br />303 866 3567 +~e ~b <br />FAx 303 832-8106 <br />Roy Romer, <br />Governor <br />DATE : May 7 , 1992 Michael B. Long, <br />Division Director <br />T0: Mr. Art Lefler <br />c/o Gary Dodson <br />Battle Mountain; San Lut~~ D J e ~ ~ ~ i ~ ~ '~ ~ ~~ <br />FROM: Harry Posey <br />RE: Tailings Pond Characterization <br />This memo is to confirm our earlier conversation today and to call your attention <br />to other items. <br />1. The purpose of the pond characterization study is twofold: (1) to determine <br />variation in metal and cyanide levels throughout the ponds in order to <br />(2) determine how to collect representative samples from each pond for future <br />monitoring or to verify that previous sampling has been representative. <br />2. The number and location of the samples taken for pond characterization is up <br />to Battle Mountain to determine. In any case the sampling should be adequate <br />to determine both the vertical and horizontal variability in the pond. <br />3. Recognizing that holding time is a critical component of cyanide analysis, you <br />should know prior to sample collection whether your contract ldb can handle <br />the volume of samples you are collecting or whether they can adgquately <br />preserve the samples to prevent sample degradation. Your suggestion to employ <br />Adrian Smith to make that determination, while commendable, cannot abrogate <br />the lab's responsibility for verifying that their reported values are reliable. <br />4. As a reminder, please recall that the NOPV abatement plan specifies that <br />environmental monitoring modifications must be complete by July 9. <br />5. The Division iterates again that we do not believe your present, in-house <br />probe method for detecting free cyanide is capable of yielding accurate <br />analyses using the direct detection method. More reliable methods indicate <br />that levels in the ponds are 10 times greater or more than the levels detected <br />by probe. Out of concern for worker safety, we recommend that vpu check with <br />MSHA nr other cyanide experts to assure that nrolonaed exposure to the air <br />e is volatiiiz <br />Please call me if you have questions. <br />HHP/ern <br />cc: Bruce Humphries <br />Mike Long <br />Larry Oehler <br />Jim Pendleton <br />Jim Stevens <br />9992E <br />