GENERAL34269 - Laserfiche WebLink

Home Browse Search

~. Design Call and Nicholas (1994) CC&V (1995-6) Wall Orientation Inter bench Slope (degree) Catch Bench Width (feet) Overall Slope Angle (degree) Inter bench Slope (degree) Catch Bench Width (feet) Overall Slope Angle (degree) East 72° 31' S2° 79° 28' 60° West 72° 48' 45° 79° 28' 60° North 72° 40' 48° 79° 40' S2° South 79° 40' S2° "Noses" 79° 80' 40° As noted above, the steeping of [he interramp angles along [he east highwall resulted from CC&V's fmding that some relatively steep natural joint sets would be intersected by the highwalls. Steepening the interramp slope has provided a highwall face that is almost parallel to the natural joint set. The steeper slope lessens the potential for failure. Performance of current slope desigi:s The performance of the current design has been evaluated by inspections and measurements, with the following results: 1. Catch Bench Performance. Inspection indicates that about 10 percent of the width of the catch benches is "used" to catch rock. There is no evidence that the majority of the debris caught by these benches is the result of highwall failure. Rather the catch material is the result of minor sloughing of individual "rocks" loosened by blasting. In only one case has there been minor slumpage and this movement does not appear to be continuing. 2. Overall Slope Movement. Monitoring of the movement of the highest, steepest slope (the southern portion of the east highwall) by electronic distance measurement equipment indicates that there is no evidence of sustained progressive or pervasive movement of the highwalls. 2. Additional Friction Angle Information on Cresson Ore ("Shear Box Testing") With respect to additional tests to affirm the friction angle of the Cresson ore, CC&V notes that in CC&V's January 9, 1996 submission, Attachment 7 to the letter, "Shear Strength Testing Results for Cresson Ore," which also was dated January 9, 1996, presented an additional test 8