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r Y III III III III IIII III <br />999 <br />MINED LAND RECL:,~~1~1 T !CN Cib'i~1C~ 1 <br />Department of Natural Resources <br />t313 Sherman SI., Room 215 <br />Denver, CO 80203 <br />303 866-3567 <br />FA X: 303 832-6106 <br />~T~i E OF CO~,ORADO <br />pF„O(O <br />~~~- a=~Q <br />G <br />•~ ~. ' ti <br />~~B Te <br />Roy Romer, <br />Gavemor <br />Michael B Long, <br />Dnison Duector <br />DATE: April 24, 1992 <br />T0: Susan Morrison <br />i <br />FROM: Jim Pendleton ~ '~ <br />RE: Seneca II-W -ne - T nical Revision 16 - Geotechnical Adequacy <br />(Permit No: C-82-057) <br />Peabody Coal Company submitted TR-16, requesting permission to mine the <br />northern portion of the Seneca II-W mine site. Upon early examination of the <br />application and site, Bruce Stover and I both voiced concerns regarding the <br />geotechnical adequacy of the mine plan. Specifically, we were concerned that <br />certain facilities, including the haul roads, sediment pond #005 and topsoil <br />and overburden stock piles might be proposed in geotechnically inappropriate <br />locations. At our request, Peabody Coal subsequently contracted with a <br />geotechnical consultant, John Ivey of Amuedo & Ivey, and a civil engineering <br />firm, Ground Engineering Consultants, Inc. to review the geotechnical siting <br />and prepare appropriate designs for these facilities. The report of these <br />investigations was submitted March 17, 1992. Bruce Stover reviewed these <br />reports and prepared a second memo presenting remaining geotechnical adequacy <br />concerns. On Thursday, April 9th, at the request of Peabody Coal, <br />representatives of the Division met with Tom Wainright and John Ivey to <br />discuss our remaining adequacy concerns. This memorandum presents a brief <br />summary of our remaining geotechnical adequacy concerns for TR-16. <br />Mr. Ivey has thoroughly mapped the geotechnical characteristics of the <br />technical revision area. He has delineated significant areas of the site as <br />"Unstable Ground", "Potentially Unstable Ground" and "Stabilized Ground ?". <br />Minor relocation of many of the facilities has managed to avoid a portion of <br />these undesirable locations. The operator has also indicated that it is no <br />longer requesting approval of Haul Road H, the majority of which crosses <br />unstable ground. <br />The majority of our remaining concerns address the portion of Haul Road G <br />between Stations 51+50' and 63+80'. Between 54+00' and 63+80' no bore holes <br />were completed because of seasonal inaccessibility. This entire interval is <br />delineated as "Unstable Ground". In our meeting, John Ivey expressed relative <br />comfort with the geotechnical stability of the portion between the stream <br />channel at 58+50' and 63+80', because this portion of the haul road descends <br />the slope parallel to the fall line. In contrast, however, the segment of <br />Haui Road G between stations 51+50' and 58+50' crosses the slope. We continue <br />to be concerned that this cross slope excavation may initiate renewed slope <br />