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casing and the annular space between the conductor casing and <br /> the drilled hole filled with sealing material to the depth <br /> specified in Part A of this section. <br /> 4. Wells situated in "hard" consolidated ANNULAR SPACE <br /> formations (crystaline or metamorphic rock). An oversized <br /> hole shall be drilled to the depth specified in Part A of <br /> this section and the annular space filled with sealing ^_— SOIL <br /> material. If there- is significant overburden, a conductor <br /> casing may be installed to retain it. If the material is <br /> heavily fractured, the seal should extend into solid GROUT SEAL ti+ cA51NG <br /> material. If the well is to be open-bottomed (lower section <br /> uncased), the casing shall be seated in the sealing material <br /> (see Figure 5A). <br /> 5. Gravel packed wells. <br /> a. With conductor casing. An oversized / DRILLED HOLE <br /> hole, at least 4 inches (100 millimetres) greater than the I (Open bottom) <br /> diameter of the conductor casing, shall be drilled to the r� <br /> depth specified in Part A of this section and the annular <br /> space between the conductor casing and drilled hole filled <br /> with sealing material. (In this case the gravel pack may A. WELL DRILLED IN ROCK FORMATION <br /> extend to the top of the well but to prevent contamination by <br /> surface drainage, a welded cover shall be installed over the <br /> top in the space between the conductor casing and the <br /> production casing, see Figure 0). <br /> b. Without conductor casing. An oversized WATERTIGHT CAP GRAVEL FILL PIPE <br /> hole at least 4 inches (100 millimetres) greater in diameter ANNULAR GRAVEL FILL PIPE ANNULAR <br /> than the production casing, shall be drilled to the depth SPACE SPACE <br /> specified in Part A of this section and the annular space SOIL <br /> between the casing and drilled hole filled with sealing SOIL ; <br /> material. If gravel fill pipes are installed through the <br /> seal, the annular seal shall be of sufficient thickness to GROUT SEAL }f GROUT SEAL <br /> assure that there is a minimum of 2 inches (50 millimetres) 7 <br /> between the gravel fill pipe and the wall of the drilled hole. ' <br /> The gravel pack shall terminate at the base of the seal (see i} <br /> Figure 5C). If a temporary conductor casing is used, it shall <br /> be removed as the sealing material. is placed. CONDUCTOR <br /> GRAVEL PACK CASING VARIOUS <br /> 6. For wells situated in circumstances differ- FORMATIONS GRAVEL PACK <br /> ing from those described above, the sealing conditions shall .-END OF CASING <br /> be as prescribed by the enforcing agency. <br /> CLAY (Shoe) <br /> 7. Converted wells. Wells converted from one CASING <br /> use to another, particularly those constructed in prior years <br /> without annular seals, shall have annular seals installed to INNER CASING <br /> II the depth required in Part A of this section and at the <br /> thickness described in Part E. Where it is anticipated that <br /> a well will be converted to another use, the enforcing agency •'• <br /> may require the installation of a seal to the depth specified B.WITH CONDUCTOR CASING C.WITHOUT CONDUCTOR CASING <br /> for community water supply wells GRAVEL PACKED WELLS <br /> This statement presumes that land use planning has taken <br /> place and that. zoning requirements are in effect. Figure 5. SEALING CONDITIONS FOR UPPER ANNULAR SPACE- <br /> HARD ROCK FORMATIONS AND GRAVEL PACKED WELLS <br />