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INTRODUCTION <br />1.01 General <br />On behalf of Aggregate Industries West Central Region, Inc. (Aggregate Industries), Haley & <br />Aldrich, Inc. (Haley & Aldrich) has prepared this Geotechnical Addendum to the 2001 Notice <br />of Intent to Continue Mining Operations/Annual Report for the subject Regular (112) Mining <br />and Reclamation Permit. This conforms to Rule 6, Section 6.5 and is also required to comply <br />with Permit Amendment No. 5, carried over from Permit Amendment Nos. 3 and 4. <br />Specifically, [his exhibit provides supplemental data required by the Division of Minerals and <br />Geology (DMG) per Stipulation No. 4 in the Letter of Conditional Approval of Amendment <br />4, dated 16 February 1995. <br />1.02 Purpose and Scope <br />The permit Amendments describe in detail an "Observational Method" to mine slope <br />development being implemented at the quarry whereby conservatively designed "default" <br />slope angles may be modified to steeper configurations based on ongoing observation of slope <br />performance, collection of rock mass property data, and slope stability evaluations. Default <br />slope angles consist of a one to one ratio of highwall height to bench width (1H:1V) slopes <br />with maximum highwalls not exceeding MSHA regulation requirements, except the east side <br />of the Central Quarry, are implemented without special geotechnical analyses based on prior <br />analyses of global conditions at the quarry. In the east side of the Central Quarry, the default <br />slopes are 40 feet (ft) highwalls and 50 to 60 ft benches. <br />:\PROIEC'I'S\?02W INOrrisun QuarrylWN\_'W I\Repon\'_IMII ~ewechnical aJJenJum.J« <br />