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r, <br />~I <br /> <br /> Q. BACKGROUND <br /> <br /> 2.01 IVline Plan Amendments and Technical Revisions <br />' Mine Plan Amendments Nos. 3 and 4 revised the approach to slope design at the Morrison <br /> Quarry with the implementation of the Observational Method throughout the quarry. These <br /> Amendments carried over in Amendment No. 5. The significant changes presented in these <br />Amendments were a reconfiguration of the east side of the Central Quarry to address slope <br /> instabilities in that area and the provisional change in slope inclinations elsewhere to as steep <br /> as O.SH:1V based on evaluations of preliminary slopes established at 1H:1 V. As a condition <br />' of the Amendments, the steeper slopes and revised configuration could be implemented only <br /> in accordance with specific, predetermined steps outlined in the Observational Method. <br /> Conditional approval of the Amendments required annual reporting of geotechnical data, <br /> slope stability evaluations, and current mine conditions in areas where steeper slopes were <br /> utilized, or where unusual conditions were encountered. <br />' Technical Revision No. 3 modified the mine plain of the Central Quarry by allowing mining <br /> from Bench A (el. 6453 feet) down to Bench E (el. 6253) to be excavated with 30 h benches <br /> and 50 ft highwalls. <br /> 02 Ob <br />2 <br />ti <br />l M <br />th <br />d <br /> serva <br />. <br />ona <br />e <br />o <br /> The Observational Method as described in Mine Plan Amendments Nos. 3 and 4, is a step- <br />' wise approach to slope design by which new information is regularly used to upgrade <br /> previous analyses. This method was utilized as a practical approach to designing slopes in a <br /> rock mass with variable conditions, in which some areas are poorly exposed and difficult to <br />' characterize. This method establishes baseline conditions during initial evaluations. <br /> Observed initial conditions are then compared with [he baseline for analyses. As a required <br /> condition of permit approval, annual geotechnical reports are presented to provide the <br />' opportunity for periodic regulatory review of geotechnical conditions relating to mining <br /> activities. <br />' The Observational Method is applicable to any slope in the quarry, except the west side of the <br /> Central Quarry, which is sleeper than 1 H:1 V. <br /> <br /> <br />1 <br /> <br /> <br />' G'~PROIECTS:O?00 Morrison Quarry100g~?OOOkepori~?000 geo~echnical aJJenJum Joc <br />