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H. BACKGROUND ' <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. The <br /> significant changes presented in these Amendments were a reconfiguration of the East Highwall <br /> ' of the Central Quarry to address slope instabilities in that area and the provisional change in <br /> slope inclinations elsewhere to as steep as 0.5H:1 V based on evaluations of preliminary slopes <br /> established at 1H:IV. As a condition of the Amendments, the steeper slopes and revised <br /> ' configuration could be implemented only in accordance with specific, predetermined steps <br /> outlined in the Observational Method. Conditional approval of the Amendments required annual <br /> reporting of geotechnical data, slope stability evaluations, and current mine conditions in areas <br /> ' where steeper slopes were utilized, or where unusual conditions were encountered. <br /> The Observational Method as described in Mine Plan Amendments Nos. 3 and 4, is a step-wise <br /> ' approach to slope design by which new information is regularly used to upgrade previous <br /> analyses. This method was utilized as a practical approach to designing slopes in a rock mass <br /> with variable conditions and which is in some areas poorly exposed and difficult to characterize. <br /> A key factor of the method is that baseline conditions are established during initial evaluations; <br /> observed conditions are then compared with the baseline. Annual geotechnical reports are <br /> presented as a required condition of permit approval and to provide the opportunity for regular <br /> ' regulatory review of geotechnical aspects of mining activities. <br /> According to permit conditions, the Observational Method is applicable to any slope in the <br /> quarry, except the East Highwall of the Central Quarry, which is steeper than an 80 ft highwall <br /> and 80 ft bench configuration. The method also applies to the East Highwall if the slope is <br /> altered from the previously approved slope reconfiguration of 40 ft highwalls and 50 to 60 ft <br /> benches shown in the approved Amendments. In addition, CAMAS is applying the method to <br /> the approved slope reconfiguration for the East Highwall to verify baseline design assumptions. <br /> t2 G:\PROD ECTS\'_02 W\002\97AN N RPT.W PF <br /> 1 <br />