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Section 780.18(b) Continued. <br />4) The shallow alluvial welts are completed in unconsolidated alluviallcolluvial <br />materials. Well closure will involve filling the well casing with clean sand to within <br />3 feet of the ground surface, cutting and pulling the casing at this level, and filling <br />the remainder of the borehole with cement to create a 3-foot surface plug. A steel <br />fence post will be set in the cement surface plug as a permanent marker. <br />5) Same of the deep wells have a cement surface plug and collar around the casing <br />extending no more than 10 feet below grade. All deep wells will be inspected for <br />the presence or absence of a cement surface plug and collar, as this will affect <br />closure requirements. <br />6) Current well depth and casing condition will be evaluated by inserting a wireline <br />into the borehole and determining how deep the line will reach. Measured depth <br />will be compared with original well depth, based on available borehole logs. <br />7) Based on drill logs and water level measurements, some of the boreholes may be <br />completed in a ground water unit exhibiting artesian conditions, requiring special <br />sealing techniques per Rule 4,07.3(2). Borehole conditions (re: artesian flows at <br />the surface) will be evaluated by evacuating any boreholes where potential <br />artesian conditions exist and allowing them to recharge for at least 3 days. If <br />recharge water levels indicate artesian conditions, boreholes will be sealed from <br />bottom to within 10 feet of the surface with a cement slurry. <br />8) Well sealing and plugging requirements will be dependent on the results of the <br />borehole evaluations previously outlined as Steps 5, 6, and 7, summarized as <br />follows: <br />Sa) Boreholes where the wireline probe reached within 10-20 feet of original <br />depth or through the coal bed and where artesian conditions were <br />confirmed -Using awireline-conducted tool, perforate the casing starting <br />at the bottom of the borehole. The perforating method will be designed to <br />maintain the integrity of the casing with perforations at 20-foot intervals. <br />After perforating, coiled tubing will be inserted downhole to the bottom of <br />the casing and a cement slurry will be pumped down the coiled tubing <br />while gradually withdrawing <br />MR-37 780-88b Revised -September 2002 <br />