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STEEP ROCK SLOPE RETENTION <br />When the south portal was developed, near vertical rock faces were excavated to <br />provide room for a warehouse, shop and offices. The warehouse and shop will be left in <br />place for the postmining commercial land use. Thus, the near vertical rock faces will be <br />left in place. The steep rock faces are shown on Figure 14-14. <br />Rule 4.27.3(3) states in part that "The person who conducts the surface coal mining <br />operation must demonstrate to the Board or Division, using standard geotechnical <br />analysis, that the minimum static factor of safety for the stability of all portions of the <br />reclaimed land is at least 1.3. This Rule should apply only to regraded areas, not the <br />rock cut slopes in native material that will not be disturbed during reclamation. <br />Rule 4.27.3(8) allows alternative specifications to be utilized as long as such <br />alternatives are as environmentally sound and structurally stable as that resulting from <br />compliance with requirements of 4.27. Even though the provisions of Rule 4.27 may not <br />apply to the subject steep rock faces, the following demonstration is presented: <br />Steep rock slopes frequently exist at surface coal mining operations. Design criteria for <br />haul and access roads allow cut slopes in rods to be as steep as 0.25h:1v without <br />stability analysis. Additionally, highwall remnants allowed under Rule 4.14.1(2)(f) need <br />only be suffidently stable so as not to pose a hazard to the public health and safety or <br />to the environment. <br />The steep rock faces at the south portal have been in existence for over thirty years. <br />Although there has been some rock spalling, there has never been a slope failure. Over <br />the thirty year period, the rock faces have been subjected to a wide variety of <br />environmental extremes and still remain stable. The long term stability of the steep rock <br />faces is by far the best indicator of their continued stability. <br />In my professional opinion, the steep rock faces located behind and north of the <br />warehouse, shop and offices are environmentally sou®oo®d structurally stable and <br />have a static factor of safety of at least 1.3. ~ogp REC/.r!® <br />Stoves ~a Date <br />1923~\~`~o <br />Go <br />~~~~~ e <br />~~e~p <br />i~ <br />PR3 A14-10-1 06/07 <br />