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e "+o. 3 - Desi�,m ,e <br /> 1::e sedimentation and drainage control strict :es, at MLie No. 3 include the <br /> follow-yng. Design details are sll-awns in Plates 3-1 and 3-2. Design criteri r't <br /> are su sized in Calculation. paragraph 5. <br /> a.) Sedimentation: Ponds Min. Required Storage <br /> 3-1 = North Side 0.29 ac-ft <br /> 3-2A South Side c)cbired storage <br /> .3-28 - South Side of 0.37 ac-ft <br /> Sedimen ati'm pond 3-1 has been constructed to collect .and treat sedi=nt- <br /> laden runoff from dra.image area 3-1. This pond will also collect mine efflue;.t. <br /> lk :ification of this pond include slope increases to 2:1 and 3:1 from existing <br /> 1.5:1.0 slopes, install.atior. of an me gency spillway, gated outlet ,,marks with <br /> rip rap protection relocation of mine effluent discharge pipes and en-L'argment <br /> of the pc:nd. ibis pond may require lining with 'bu yl nihber (30 :rsl. ti- ck) to <br /> mirini-e potential seepage losses. Such seepage Josses c„^i:?d cause slope fail- <br /> =es e_t er in th.,e steep waste d-up or weathered shale bedrock. <br /> Sediu.Entation Ponds 3-2A and 3-2B have been canet_.izted to collect and 'great <br /> sedimant laden r ruff from drat age area 3-2. The '-r_ca_ticn cf these two ponds <br /> inc'luda increasing downstream and upstrean slopes from 1.5:1 to 2:1 and 3:1, <br /> installation of an merge_nL-7 spillway and gated outlet wv.ks with rip rap protec- <br /> ti.on. <br /> Rr.off from within the d st=bed pad areas will be ccrfiz-ed and diverted to <br /> the ponds by underate regradi qg- of roads c::d appropriate pi acemLmt of yea-mil <br /> The rLmoff from adjacent areas will be diverted by ditches amyl earth ?-e=. <br /> The r noff from la.^.L above &.e 17ig-r,ail will be collected by an e3 sting al-=.dored <br /> road that traverses the entire hig'_crzl.l. <br /> NOTE: For design of new #3 pond (lower coal bin) contact <br /> Mid-Continent Environmental Coordinator <br /> -h- <br /> 48 <br />