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Pressure Cats Method. In the pressure cap method, the grouting is done with the hole drilled about 2 feet (0.6 metre) below the bottom of the. conductor casing and the remainder of the well drilled after the grout is in place and 41 set. The grout is placed through a grout pipe set inside the conductor casing. CCe LO 1. The casing is suspended about 2 feet w 2 (0.6 metre) above the bottom of the drilled hole and filled L with water. 2. A pressure cap is placed over the conductor �4 ` casing and grout pipe extended through thecap and casing to � the bottom of the hole. 3. The grout is forced through the pipe, up F into the annular space around the outside of the conductor s LO casing, to the ground surface. 4. When the grout has set, the pressure cap and the plug formed during grouting are removed and drilling � w LL of the rest of the well is continued. o q+: 0 Because there is the possibility that coarse aggre- ti, Z gate will "jam" the grout pipe, concrete cannot be used as a ,, sealant when this method is used. # �+Z- Continuous Injection. This method, called the Normal Displacement Method in the oil industry (which developed W zcc it), involves pumping grout through a tube or pipe centered in '� 'y~ the casing via a "float shoe" fitted at the bottom of the # 3 ;�. casing. The grout is forced up into the annular space to the ; � � ground surface as is the case with the pressure cap method �I •, a (above). The tube is detached and flushed. The float shoe, which has a back pressure valve, is drilled out. Because x there is the possibility that coarse aggregate will "jam" the w i � grout pipe, concrete cannot be used with this method. a a n �? cc Sealing-off Strata ' ` � - cc r When the hole for a well is drilled, a strata may be found that produces water of undesirable quality. To prevent a x# ¢ a the movement of this water into other strata and to maintain LL the quality of the water to be produced by the well, such aCLL strata must be sealed-off. Also, where a highly porous non- water producing strata is encountered, it too must be sealed- off to prevent the loss of water or hydraulic pressure from the well. �. . The follow' methods can be used se in al' -off � sealing -off or zones (see Figure 11). In addition, several of the methods described for sealing the upper annular space can also be used. Pressure-Grouting Method. This method can be CL employed where a substantial annular space exists between the well casing and the wall of the drilled hole.