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Rinker hlatcnals <br /> , April 18, 2QD2 <br /> Page� <br /> Bascd on our observations, it is our opinion thai the sm�ctural fill placement we observed <br /> during our:;ite visits was generally placed and compacted according [o our recommendations and <br /> the Letter ofUnderstanding. <br /> Near Ihe end of the 2001 �,�rading scason, topsoil was placcd along lhe southcast and northeast <br /> property lines. The topseil was track-walked in pincc. In additian, loosc soil berms werc placeti <br /> to control surCace watcr runoFf along thc west edge of thc property. <br /> REMOVAL OF TEMPORARY RAMPS AND UNDUCUMENTED NORTHEAST FILL <br /> AREA <br /> Undocumented fill associatcd with temporary haul ramps that werc conshvctcd down to the <br /> pit floors from the top oC the `iighwall at the site wu removed and replaccd with structural fill. <br /> "11�e tem�or.ary'haul ramp construcred during the 2000 grading season �vas generally compacted to <br /> at Ie�st 92 percent MDD, however, thc �vestern ponion of the ramp was removed during <br /> subsequent mming activities. Thr, zdges oI lhe 2000 ramp that remaincd were (latte�ed to 3H:1 V <br /> and bcnched into during fill placcmcnt in 2001. <br /> Two rmnps wcrc constructcd for thc 2U01 grading work. Thc ramps wcrc constructed at thc <br /> north and :oulh cnds oC the main r�orth-south pit highwull. The south ramp �vas generally <br /> wmpacted �o at teast 92 perocnt MDD, but a portian of it wa,removcd such that the south end of <br /> the north-south highwall could Ue flattcred. Thc north ramp was entirely rcmoved and replaced <br /> with structu-ol fill. <br /> Pill placed in March of 2001 in the northeast portion of the site prior to our noti�cation was <br /> subscquenH.� removed due to lack of documentation and conccros regarding the fill quality. <br /> llased on nur observations and testing during our site visits, it is our opinion tha; the <br /> undocumen�ed 61] was rcmoved and replaced with suitable sWctural fill Ihat wa, placed and <br /> compacted xccording to our recommcndations and thc I.etter of Understanding. <br /> FSA C}ETEN fION POND <br /> During grading, groundwater seepage was observed emanating from ncar [t�c top of thc <br /> highwall cul located immediatcly �vcst of the Food Services of America (FSA) detention pond. <br /> "Che top of :he highwall was located about 5 to 10 feet west of the FSA property li,n.�. The <br /> secpage was unusual in this area a[ the obscrved elcvation because Sr�undwater is located below <br /> ,hc bottom of the mined pit or at least 30 fect lowec The observed seepase was evident as a wet <br /> ;pot on the h:ighwall that was ebout 25 fect long and 10 Ccet high and at about thc samc cicvation <br /> i �s the PSA detention pond. Occasionally, free flowing watcr was o;.served emanating from the <br /> i�ighwall thruugh more poraus laycrs within lLc sznd and gravcl outwash depasit. The seepage <br /> ivas typically Icss that about '/, gallon per minutc. <br /> ' The quautiry of seepage apptared to increase and dccrease in response to the water ]evel in <br /> the PSA detr.ntinn pond. It is our npinion that the obscrved seepage was the result oC detention <br /> pund wa(cr infillraling infu thc ouhvash soils and migrating ta the highwall. <br /> G c a P n g i n e c r s Fi1cNu. GI92-007-0)•IUO <br />