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ID: ~ RUG 16'95 955 No.003 P.03 <br />Memo to 8erhaa Xeffelew <br />Cresson Dine GEOTTX / LIFT Revisions <br />page 3 <br />equipment". while the application doesn't specify the <br />particular "equipment" ufled I asFUme it was the B5 ton haul <br />trucks in u6e at the CR&SSON site. Frankly, I am surprised by <br />the results. The literature and my experience suggest that <br />Chia is an astounding compaction accomplishment which defies <br />conventional engineering wisdom. This is not to Bay its <br />impossible, but I must confess.to skepticism. CC&VG should <br />provide more information about the placement methodology for <br />the test lift,. including dumping, material grading subsequent <br />to dumping, and the determination of actual equipment pass <br />count and traffic distribution. As Don Pointer stated, it is <br />important to verify that the test lift placement is actually <br />representative of the placement techniques which will be used <br />for the bulk materia]. placement. <br />The revision application further states that the structural <br />otability of the relocated Carlton Tailings material ie not of <br />importance, because it will be covered with waste rock and be <br />buttressed by the relocated Highway embankment. The <br />structural character of foundational materials is important <br />for any large earthen sl'ructure. in the short tern the <br />Carlton Tailings materials will not be buttressed. Failure oP <br />tk,ib foundational material could compromise the surface <br />hydrology control structures loeatafl above the relocated <br />highway embankment. Golder states that tho•densities achieved <br />during the test- "generally" achieved compliance with the <br />design analysis parameters for the material. If this implies <br />thAt same of the results did not meet the rlesign assumptions <br />the stability model should be reanalyzed to assume the lower <br />conservative material density and corresponding lower <br />et-.renyths. The Division must insist on conservative analysis <br />of.eart-.hen structures of. this magnitude. <br />Finnnly, it lift thicknesses in excess of the approved 16- <br />inches is approved, density of the relocated Carlton Tailings <br />material should be verified by repetitive density <br />dttermi.nations on an appropriate periodic frequency, in order <br />to demonstrate compliance with the design density assumptions. <br />cc: sruce Huptphries <br />Jim 9tevena <br />Jim Dillie <br />DOC: M:\MTN\CRESuON\GTEXLIFT.kEV <br />JP/jp <br />