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on azeas above the anticipated high water line. Does your topsoil replacement plan <br />include replacing topsoil on the Phase 1 and 2A azeas? The Division will require that <br />these azeas be topsoiled, if it is at all possible. <br />4. Your reclamation plan includes replacement of 6-12 inches of topsoil. The native soils <br />according to Exhibit I have topsoil depths of from 1 foot to several feet. Your plan is to <br />establish grasses, sedges, rushes and forbs. These plants do best when topsoil depths aze <br />adequate (12-18 inches). Since there will be an overabundance of topsoil, please change <br />your plan to so that all reclamation areas will receive a range of topsoil depths averaging <br />at least 12 inches. <br />5. Your plan mentions perimeter screen berms of topsoil. If these berms are to be a <br />permanent part of the fmal reclamation, show them on the reclamation plan maps and <br />describe their dimensions and re-vegetation in detail. Since such berms would be very <br />dry unless they are irrigated, the re-vegetation plan would need to include plants that are <br />drought resistant. If the berms aze not permanent but will be in place throughout the <br />mining operation, show their location, provide their dimensions and discuss their final <br />disposition.. <br />6. Your plan includes the regulatory requirement that topsoil will be segregated from other <br />spoil. At A. I.'s adjoining Tucson Resource Mine, topsoil has not been segregated from <br />other overburden material. What is your plan to insure that pit operating personnel <br />segregate topsoil from outer materials. <br />Your plan for re-vegetation of upland areas includes a seed mix more suited to areas of <br />higher precipitation and sandy soils. Please consider changing your seed mix to the mix <br />recommended by the Natural Resource Conservation Service. Their letter of comment <br />was forwazded to Tetra Tech. <br />8. Your seeding rates for the pond bank slopes, upland azeas and other disturbed azeas aze <br />too low; however, since you maybe changing the mix and seeding rates in response to <br />item 7 above, final review of this issue will. be after the Division receives your response <br />to item (7) seven. <br />9. Your mining Phase 2 includes the construction of a slurry wall. The Construction <br />Materials Rules at 3.1.6(2) states "Earth Dams, if necessary to impound water, maybe <br />constructed if the formation of such impoundments will not damage adjoining <br />property..." The City of Brighton is concerned about the impact of the proposed <br />operation on the Morgan Smith Natural Area, which lies between Phase 2 and the South <br />Platte River. The natural azea has a lazge community of cottonwood trees. Groundwater, <br />which is needed by the trees, moves towazd the river through the alluvium. It appears <br />that the slurry wall may cut off ground water flow to the natural azea. Demonstrate that <br />the sluny wall will not block the groundwater flow into the natural area to the extent that <br />it will cause the trees and other vegetation reliant on the normal groundwater surface to <br />die from lack of water. What is the expected shadowing effect on the ground water <br />table? Will the shadowing effect be enough to cause cottonwood trees and other <br />