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• • <br />Mr. Peter Evans - MLRD <br />Technical Revision -Dam D <br />Page 2 <br />A proposed complete plan for sediment control for the Dam D area will <br />be carried out as follows: <br />1) Prior to mining, surface runoff from the Northeast <br />area will drain to the bottom of the active mining <br />pit due to the elevation differential; any surface <br />runoff from both the East and (south will be collected <br />and drained to the existing Dam D. In the meantime, <br />the 70' bank shall be built up. The 300' pipe or <br />diversion ditch shall also be installed approximately <br />50' within the lease boundary to divert the fresh <br />water away from the mine water as indicated on the <br />attached map. <br />2) During the mining, all undisturbed runoff will <br />be diverted to Magpie Creek Diversion Channel <br />through the 300' pipe/diversion ditch. All mine <br />water will drain to the bottom of the pit, which <br />happens to be the lower elevation and also located <br />at the East of Dam D area. The existing West haul <br />road functions like a collection ditch to bring <br />all the Northeast surface runoff to the bottom of <br />the pit. <br />3) After the mining is finished in the Dam D area, <br />CEC's pit continues working toward the South. The <br />. West haul road keeps extending Southward until it ~ <br />connects with the existing South Diversion Ditch. (lo~~a-~~~ ' <br />• The backfilling will stop around Dam D area as soon <br />•k'° ~- as the bnckfilled elevation reaches the design height <br />for [he floor of [hc sediment pond, Dam D. To re- <br />establish the channel bottom, a 12" clay barrier will <br />be placed five (5) feet below the surface, the es- <br />timated clay volume ~/=~ 1r2" x 200' x 8' = 60 cy. <br />~n,,.~ eoc~:l7e... <br />The Dam, and the diversion Vditches all will stay like they were per- <br />manently. No specific changes will have to be made until Dorchester <br />Mine finishes their operation in this area. The Magpie Creek Diversion <br />Channel shall be returned to its original stream channel, then this <br />un-named stream shall have to go back to its original channel like <br />it was a long time ago. <br />Topsoil removal/replacement will be handled as previously approved <br />in Permit 1177-48. Revegetation will take place between October 15 <br />and March 15 on Dam D area which have been prepared by backfilling, <br />grading and re-disCributing topsoil. The area will be seeded with <br />