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112}:E Sava OE -_- Rpril _, l~$_ <br />• The supplemental submittal, made in response to cur adeauacu review, also <br />includes a computer printout summary of a stability analusis of the proposed <br />"Overburden Pile No. 9". This analusis utilizes a computer technique~~ <br />developed by the University of Xentvcky's !dining Research Center, aid is in <br />lceepinq with the prudent state-of-the-art of stabilitu analysis. The ana]ysis <br />assumes material strength parameters for the spoil material. However, no <br />geotechnical investigation or material testing results are presented e,•ithin <br />the supplemental submittal to justify the material properties assumed. The <br />applicant, in keeping with the requirements of kale 2.05.3(6)(c), must <br />perform a geotechnical investigation of the proposed spoil pile site, in <br />order to determine the character of the soils and the bedrock, the stability <br />of the proposed foundation area and the occurrence of possible detrimental <br />ground water seeps. In addition, the applicant should collect and analyze <br />appropriate material samples, in order to verify the assumed material shear <br />strength properties. <br />The design plans included within the supplemental submitta] conform with the <br />construction and design specification requirements of Rule 4.09.2, regarding <br />valley fills, with one exception. The fill is designed with a durable rock <br />subdrain system. Material is to be placed in less than 9 foot lifts and <br />_ properly compacted. The fill is terraced with maximum. 2:l (horizontal to <br />vertical) final facial slopes between the terraced benches. Terraced bench <br />and filled top surfaces have been designed with lateral final grades of 2~ <br />t• to facilitate drainage. The plans specify the installation of permanent <br />diversion ditches to carry surface flow around the fill. Rule 9.09.2(7) rec_u_res <br />that these ditches be designed to safely carry the runoff from a 100-year, <br />24-hour precipitation event. No design hydrologic calculations have been <br />included within the supplemental submittal. The applicant must cortmlete <br />these calculations and appropriately specify a ditch design to be utilized <br />when constructing the pile. <br />/mt <br />cc: Ed Bischoff <br />IJave shelton <br /> <br /> <br />~ V- y a G aJ <br />