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SECTION 16 EXCESS SPOIL FILL <br />The following information is submitted to the Division in <br />order to meet the requirements regarding permanent excess spoil <br />disposal structures in Rules 2.05.3(6)(b) and 4.09 Disposal of <br />Excess Spoil. <br />On March 29, 1991, CTL(Thompson, Inc., completed the report <br />"Geotechnical Investigation, Section 16 Excess Spoil Disposal Site, <br />Colowyo Coal Mine, Moffat County, Colorado". The report provides <br />a geotechnical evaluation of the Section 16 Fill area and a <br />stability analysis of Colowyo's proposed design for the fill. The <br />proposed design for the fill utilized by CTL/Thompson for their <br />analysis was a fill similar in construction to the Streeter Fill <br />that is designed and constructed under the alternative design <br />standards set forth in Rule 4.09.1(3). The results of the site <br />investigation, stability calculations and knowledge of the highly <br />successful performance of the Streeter Fill lead CTL/Thompson to a <br />number of findings and recommendations for construction of the <br />Section 16 Fill. <br />A design and construction plan for this fill which followed <br />closely the design and construction of the Streeter Fill was <br />subsequently submitted to the Division on May 10, 1991. <br />MLRD later reviewed Colowyo's proposal during the preliminary <br />adequacy review process. <br />This review resulted in a determination that although MLRD <br />essentially believed the West Pit Fill could be constructed <br />appropriately under Rule 4.09.1(3) as designed, OSMRE would require <br />the fill be constructed under the requirements of Rule 4.09.2 <br />Valley Fill. OSMRE rational was that the specific design <br />requirements of Rule 4.09.2 Valley Fills, have precedence over Rule <br />4.09.1(3) General Requirements. <br />On November 19, 1991, Colowyo met jointly with representatives <br />of CMLRD and OSMRE to discuss the permitting of the two excess <br />spoil valley fills; West Pit and Section 16. The meeting (see <br />attached memo from OSMRE) led to a discussion of the ability of the <br />excess spoil fill designs to meet a number of the specific <br />requirements of Rule 4.09.2 Valley Fills. <br />Colowyo agreed that the design and stability analysis would be <br />supplemented so as to demonstrate compliance with Rule 4.09.2(3) <br />(a,b,c,d). CTL/Thompson completed a review of this Rule in their <br />correspondence dated December 16, 1991 attached herein. <br />Colowyo also committed to meeting the requirements of a <br />subdrainage system to be extended from the head to the toe of the <br />fill. CTL/Thompson had initially provided a design for a <br />