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I. INTRODUCTION <br />1.01 General <br />On behalf of Aggregate IndusMes West Central Region, Inc. (Aggregate Industries), Lyman <br />Henn, Inc. (Lyman Henn) has prepared this Geotechnical Addendum to the 2003 Notice of <br />Intent to Continue Mining Operations/Annual Report for the subject Regular (112) Mining and <br />Reclamation Permit. This conforms to Rule 6, Section 6.5 and is also required to comply with <br />Permit Amendment No. 5, carried over from Permit Amendment Nos. 3 and 4. Specifically, <br />this exhibit provides supplemental data required by the Division of Minerals and Geology <br />(DMG) per Stipulation No. 4 in the Letter of Conditional Approval of Amendment 4, dated 16 <br />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" slope <br />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:1 V) slopes with <br />maximum highwalls not exceeding MSHA regulation requirements, except the east side of the <br />Central Quarry, are implemented without special geotechnical analyses based on prior analyses <br />of global conditions at the quany. In the east side of the Central Quarry, the default slopes are <br />40 feet (ft) highwalls and 50 to 60 ft benches. <br />