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• • I <br />' replacement well for M-13 at another location. The borehole was abandoned by Layne <br />Environmental Services, Inc. in accordance with the State of Colorado abandonment standards. <br />Details of the abandonment are presented below: <br />Interval (ft) Material <br />surface - 20 Portland Cement <br />' 20 - ]SO Backfill with native cuttings <br />150 - 171 (TD) Bentonite Grout <br />' Between each borehole all drilling equipment which had been used in the advancement of the <br />' borehole, or had come in contact with water produced from the borehole was decontaminated <br />by removing formation material and loose dirt from the equipment, steam cleaning, and au• <br />' drying. <br />Each of the wells were developed, after the grout had set, by a combination of surging with a <br />surge block, bailing, and pumping with a submersible pump. This procedure extracted a <br />'' considerable amount of fines from the formation. Development was continued at each well until <br />the discharge had cleared and was essentially free of suspended material, and th~ water quality <br />' field parameters stabilized. <br />' GEOPHYSICAL LOGGING <br />' Colog, Inc. of Golden, Colorado mobilized to the site on October 27, 1993 to geophysically log <br />~' monitoring well M-14. The geophysical log suite was run in the completed, cased well from the <br />surface to total depth, and included gamma, neutron, and EM conductivity logs. This is the <br />' same suite of geophysical logs that were run in wells M-9, M-l2, and M-13 on July 27, 1992. <br />Due to its proximity to well M-13, the Division agreed to exclude well M-13R from the <br />' geophysical logging requu•ement. <br />' The gamma log is a recording of the natural formations' radioactivity, and is u9ually attributed <br />to clay minerals. The neutron log measures the effects of neutron scattering and collisions with <br />~ ' -5- <br />