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Rinker Materials <br /> April 18, 2UO2 <br /> Page 3 <br /> FLATTE:NING OF THE NORTH-SOU7�i PIT HIGHWALL <br /> The main north-south highwalf on the west side o( the mined pit area within [he site was <br /> f�attened to a 3H:IV (honzontal to vertical) or flattcr slope. T'his was necessary to achieve an <br /> acceptable transition From decp fill areas to the cut arcas. Steep cuts resulting From mining <br /> activities around du haul :aad constructed during the 2000 �Tading season in the northeast <br /> portinn of the site wcre also tlattcned to 3}I:1V during grading in 2001. Based on our <br /> obser�ations, it is our opinion that the nain north-south highwall was flattened to an inclinatiun <br /> no steeper Ihan 3H:lV in general accordance with our recommendations and the Letter of <br /> Understand ing. <br /> As described in the Letter of Understanding, (lattening of'the highwalls adjncent ta cxisting <br /> properry lines was not possible. The highwalls that exisled along the King ExWsionc property <br /> line (ro the suuth), the Food Services of America, FSA, property line (on Ihe eastside in the <br /> southcast comer), and thc Merrill Creek Par6-way right-of-way (to the north) were not tlattened as <br /> the mi��ed pi!s wcrc cxcavated too close to thcse proparty boundaries. <br /> BENCHING <br /> Pill placed against native or previously compacted fill slcpes stee�x:r than SH:1 V was <br /> henched or I:cycd into th� slopc face. 'ffiis allowed for fill placement and compaction to occur on <br /> � near Icvel u�or4:ing surfaces. Pill [hat was placed against Ihe flattcned 3I{:IV main north-south <br /> highwall wns also bcnched into d�e native soils. Benching activities generally occurred during <br /> the fill placr.ment process. Fill was �laced and compacted as close as practical to the highwalls <br /> � that werc nut flattened, as described above. Bas:d on our observations, it is our opinion [hat <br /> benching obscrved during aur site visits was perfortned in gcneral accordance with our <br /> r <br /> recommend;itions and the Lettcr of Understanding. <br /> STRUCTURAL FILL PLACEMENT AND COMPACTION <br /> We obscrved placcmcnt oC swctural fil] at thc site dunng the ZOOt grading season. Fi]t <br /> placcment and compaction w�s observcd on an intcrmittent basis betwcen March 23 and <br /> Oc[ober l2, 2001. A minor amoimt of fill was alse placed during thc 2000 gradin� season. The <br /> (iil n�as plattd and compacted as structural ti!I. The structural fill was ganerally i:valuated by <br /> complcting in-place density tests aud by probing with a '/:-inch-diameter stccl probr, rod. Onsitc <br /> soils cut from thc site wcre uscd as strucmml fill and the fill was rypically placcd in 3- to 6-inch <br /> !oose liRs using scrapers. The rough grading plan for[he site was modified &om ihe criginal plan <br /> (dated May :999) during the course o(grading. The originai objective was to have the sRucmral <br /> fill placed �ithin approximatcly 5 fcet of rough grade compacted to at least 95 percent of the <br /> maximum dry density(MDD) dctcrmined in aceordance with ASTM D li57. This ohjective was <br /> achievcd in most �rcas. However, becausc oC changcs of the grading plans in some areas therc <br /> may be only 3 to 4 fect of struc[ural fill compactcd to a[ least 95 pe:rccnt MDD. Structural fill <br /> placea 5 Ceet and below Gom rough },�adc was placed and compacted to at Icast 92 perccnt of the <br /> MDD. The soils were moisturc-condi[ioncd (generally dricd) as necded to achicve proper <br /> compaction during grading. <br /> !� c o E n g i u c c r s Pile No. 6172�00J�07-I UO <br />