2001-05-22_REVISION - M2000158 - Laserfiche WebLink

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ENVIRONMENT, INC. MAV 22, 20D 1 PAGE 5 starts. Aline has been added showing when planning for riprap work will begin. Prior to Platte Sand b Gravel reaching this line a map showing where river bank armoring will need to be done will have been submitted and approved by the Division. Also at that time, the bond will be evaluated to determine the cost to rip-rap the lake banks that will be created in the near future. At no time will mining take place within 400 feet of the river without first having armored the banks on the riverside that are subject to erosion and less that 400 feet from the excavation area. This line is at least 430 feet from the closest structure that would be affected by down cutting if the river flooded. Note that there are no lake banks next to a structure that could be affected if flood water entered the excavation area and that mining will not be within 400 feet of the river. Armoring on pit side banks will begin once 500 feet of final shore line has been created in an area needing armoring. No more that 500 feet of erosion sensitive final pit perimeter, will be exposed without armoring, at any one time during the life of the mine. Armoring will be done concurrent with reclamation so PS&G stays within the 500-foot limitation. The bank sloping will be done prior to armoring, the gradation test will be done to see if the in situ material is acceptable, and the riprap will be placed. Resoiling and revegetation will then take place according to the proposed plan. Mining is not expected to reach an area where armoring of lake banks will be necessary for 10 or more years. Armoring will be completed prior to mining within 400 feet of the river where the armoring is needed. The areas that need to be armored will be identified on a map that will be submitted to the Division for review and approval. The operator will continue to monitor the river banks as mining progresses and if additional areas are identified after the first map is submitted a revised map will be prepared and submitted for Division review. on a conservative side mining is not expected to reach the river area within the first 10 years of the mines life. xne estimates cost Review of the Division cost estimate and methodology is accept- able to the applicant. While they believe they can do it at a lower cost, it is understood that the cost for the Division to do the job is greater than the applicant's cost. The applicant is choosing to use concrete rubble but that material may not be available to the Divi- sion. Thus, using quarry rock is the only alternative when calculat-