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and refining the design based upon observed conditions. Based on the observations and <br />evaluations at a given stage, the next stage of the operation is designed and <br />implemented. <br />Using this method, Phase IA of the excavation process will involve an "experimental" <br />excavation which will consist of slopes of 50 ft wide benches and 40 ft tall highwalls in <br />various orientations well within the mining limits. Phase IB benches and highwalls will <br />be developed based on the performance of Phase IA. Evaluations will consist of <br />observing rock mass behavior, mapping rock mass features, reviewing stability analyses <br />in light of updated information, and / or kinematic analysis. Periodic review will be <br />done in order to compare current rock mass conditions and slope behavior to those <br />observed in the initial phase. <br />B. Bench and Highwall Configuration <br />Typical bench and highwall configurations are presented in Figure D-3, Typical Bench <br />and Highwall Cross Sections. There are two planned designs for benches and <br />highwalls. Above elevation 5800, benches will be 50 ft wide and highwalls will be 40 <br />ft tall. Below elevation 5800, benches will be 40 ft wide and highwalls will be 50 ft <br />tall. <br />Highwalls will generally be developed in 40 ft high lifts where practical which <br />corresponds to the typical drill length for blasting holes. For highwalls greater than 40 <br />feet tall, which are possible for the lower portion of the quarry, blasting will be either in <br />multiple lifts of 40 ft or less, or drilled full length with longer drill rod strings. Rock <br />will be loosened and fragmented by conventional blasting, then loaded into an in-pit <br />mobile primary crusher(s), with conveyor transport to the main process area. <br />C. Reserve Quantities and Mine Life <br />Reserve quantities and timetables discussed in this section are based on volumes of <br />material in-place including saleable rock and overburden. Estimated durations of <br />phases is being provided by Applegate Group, Inc. Table D-1, Estimated Volumes, <br />shows the estimated in-place volumes for each phase as well as the estimated total <br />volume of overburden and saleable material. Overburden estimates are based on an <br />assumed overburden depth of ten feet. <br />Note that the maximum build-out configurations shown are contingent upon <br />encountering competent enough rock to sustain the slopes as shown. Ongoing <br />geotechnical evaluations using the observational method will determine the final build- <br />out, which may be significantly less aggressive than shown on the figures. For all <br />mining phases, mined slopes which are at the final build-out configurations will be <br />reclaimed concurrent with mining in later phases. <br />\\Server0l\common\PROJECTS\106052-000 Parkdale Mine Plan\R. Records and Correspondence\R11 Reports\Permit_1_24_08.doc