Laserfiche WebLink
<br /> <br />Exhibit D - Mining Plan <br />1. Please specify the average depth (inches) to which topsoil will be <br />stripped for each mining phase. The soils data (Exhibit I; <br />application) indicate soil depths in the plant area ranging from 6 <br />to 17 inches (including subsoil) and soil depths over much of the <br />proposed pit area range from 20 to 36 inches. The operator should <br />salvage adequate amounts of soil to allow replacement to a depth of <br />10 to 12 inches on the pit slopes and 12-16" at the plant area. <br />This seems consistent with existing conditions and such amounts <br />should be feasible given the excess of material made available by <br />the creation of lakes (see Exhibit E; #1 ). <br />2. Specify the approximate amount (cu. yds.) of topsoil that will be <br />stored at any one time. <br />3. The mining plan map should be revised to show typica] topsoil <br />storage locations. <br />4. Where will the overburden be stored prior to backfill activities? <br />5. It is our understanding that only on-site overburden materials will <br />be used to backfill pit slope areas. Is this correct? <br />6. The mine plan proposes the use of a dragline for gravel extraction, <br />and then the pit slopes will be backfilled to achieve the reouired <br />3H:IV slopes. Backfilling into a lake can be difficult because the <br />material sometimes slides toward the lake center and stable slopes <br />are not achieved. <br />Please discuss your plans to create and maintain pit slopes that are <br />no steeper than 3H: IV (5 ft. above to 10 ft. below waterline) and <br />that are stable. <br />7. Does the operator anticipate the installation of an asphalt batch <br />plant? <br />8. How will the operator store fuel materials so as to avoid <br />contamination of surface and/or ground waters? <br />9. Please general]y discuss the procedures that will be used during the <br />relocation of Third Creek to ensure that preexisting flow conditions <br />are not damaged. <br />10. Page D-1, paragraph 4 seems to imply that the pits will be mined <br />without dewatering; however, there is a]so a statement that water <br />will be discharged to the South Platte River. Wi11 the operator be <br />dewatering the pit during mining operation? If not, explain the <br />statement regarding water discharge. Also, is the operator aware of <br />NPDES requirements? (Note: if the pits are to be dewatered during <br />mining, we will be asking questions regarding impacts to the McCann <br />Ditch, adjacent wells and to the local cottonwoods). <br />