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• <br />conditions is extremely unsafe. Dozers may be used to excavate the mine <br />highwalls in areas to the north, west and south of the natural gas pipeline, but <br />they will not be used in the vicinity of the natural gas pipeline. <br />The Applicant fully recognizes that temporary cut slopes having flatter angles are <br />more stable than steeper slopes. In no event will cut slopes steeper than 1h:iv <br />in the vicinity of the natural gas pipeline be allowed. In fact, the Operator fully <br />intends to see that all temporary cut slopes in the vicinity of the natural gas <br />pipeline are left in a configuration of slopes flatter than 1h:1v and preferably at <br />slopes of 2.5h:1 v. All cut slopes of 1 h:1 v will be backfilled as soon as <br />operationally feasible to ensure that these areas are properly stabilized. The <br />Operator fully, recognizes that the stability issues adjacent to the natural gas <br />pipeline are significantly more important than are the normal slope requirements <br />associated with final reclamation and will conduct his mining operations <br />according. <br />© As discussed above, the Division is satisfied that the proposed mine plan will <br />be protective of the pipeline easement from the standpoint of bulk stability. <br />However, small strains may be sufficient to adversely affect the pipeline, and <br />for this reason the installation of two or three strain gauge emplacements on <br />the pipeline would be a reasonable and prudent measure to detect any small <br />movements in the pipeline that may occur. Early detection of small <br />movements in the pipeline would allow for timely stress relieving measures <br />that would prevent damage. In summary, the Division's position on the <br />installation of strain gauges is that: <br />• The gas pipeline is a critical structure, and the consequences of a <br />failure of the could be catastrophic. As such, a high degree of <br />conservatism is called for in determining appropriate measures to <br />protect the pipeline. <br />• The strain gauges are an accepted and easy-to-use pipeline-monitoring <br />device that can be installed at a reasonable cost. The added degree of <br />pipeline protection provided by strain gauges can be realized relatively <br />inexpensively; requiring their installation a prudent addition to the <br />proposed mine plan. <br />Strain gauge installation and monitoring will require the cooperation of the <br />pipeline operator. If such cooperation cannot be secured, the Division would <br />consider proposals for alternative monitoring methods. Strain gauge specifics <br />and alternative monitoring devices are discussed further below. <br />Response: The Applicant is in full agreement with the concerns raised by the <br />DMG. <br />5 <br />