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Clayton Group Services Page 2 of 4 <br />Standard Operating Procedures <br />SOP -10 - Destruction of Monitoring Wells <br />4. Once on site, conduct a "tail -gate meeting" and review the scope of work and Health <br />and Safety Plan with drillers and any other personnel present. <br />5. Remove the casing, annular material, and surface seal. If the casing can not be <br />removed, it may be necessary to abandon all or part of the well by leaving the casing <br />in place and taking care to properly seal the well. Several techniques may be used to <br />remove casing from the well bore depending on well construction and materials used: <br />Pulling the casing - If the well was not grouted originally, it may be possible to <br />pull the casing with hydraulic jacks or by bumping the casing with the draw <br />works of the drill rig. In this technique, care must be taken not to pull past the <br />tensile strength of the casing material and breaking the casing down -hole. <br />Overdrilling - In overdrilling a large -diameter hollow -stem auger or direct rotary <br />techniques are used to drill around the casing. Overdrilling, with a diameter at <br />least two inches larger than the casing, is conducted to the full depth of the <br />previous boring. Upon removal of the casing, the hole is redrilled at a diameter <br />larger than the original boring to remove annular sealant and filter pack materials. <br />6. The volume of the hole needs to be calculated to determine the minimum amount of <br />sealing material to be placed in the boring. Typically, more than this volume of <br />sealing material will be required since some sealing material typically migrates into <br />the subsurface formations during filling of the borehole. The borehole volume coin be <br />calculated by the equation: <br />V= 3.14xr2xDx7.481 <br />Where: r = radius of the boring in feet <br />D = depth of the boring in feet <br />V = volume of the borehole in gallons <br />or <br />For 7 1/4 -inch boring: <br />V = 2.14Gal/Linear Ft. x D <br />For 8 1/4 -inch boring: <br />V = 2.78Gal/Linear Ft. x D <br />For 10 1/4 -inch boring: <br />V = 4.29Gal/Linear Ft. x D <br />For 12 1/4 -inch boring: <br />V = 6.13Gal/Linear Ft. x D <br />S:Ermr\Prof\SOPs\SOP-10.doc <br />