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_, <br />~ t3~- <br />p ~ -. 'ROCKY MOUNTAIN GEOTECHNICAL, INC. <br />' Achieving Harmony with Earth <br />' January 10, 1983 <br />-1 <br />t•Iined Land Feclamation Division <br />I t 1313 Sherman Street <br />Denver, CO 80203 <br />~•' Attn: Robert Liddle <br />Reclamation Specialist <br />' Re: Blue Ribbon Coal Company <br />Permanent Program Permit <br />Stipulation nl <br />' Dear F1r. Liddle: <br />This letter and the accompanying maps and profiles represent the <br />' detailed mapping of stability conditions along the existing <br />access road at the Blue Ribbon Mine. For purposes of this report <br />a stationing system has been utilized which is identical to that <br />' used in "Planned Profile and Cross Sections of the mine access <br />road prepared by Ute Engineering and Surveying Company and <br />provided to us for this project. A minor modification of this <br />' stationing system has been made in the southernmost bend of the <br />access road to accommodate the mapping of a portion of the access <br />road cut which does not follow the center line of the roadway.The <br />information contained on the maps and profiles should be largely <br />' self-explanatory. )lowever,.in summary, it would appear that from <br />Station 10+00 to 22+00 (essentially the entire uppermost portion <br />of the access road) the colluvial cover is less than 10.5 feet in <br />thickness and there is no apparent existing landslide type mass <br />toasting activity. Therefore, it is only in the zone of <br />approximately 6+00 to 1D+00 where a sufficient thickness of <br />colluvial soil is aresent to indicate a potential for <br />instability. Indeed within this zone, two separate landslide <br />features are present above the access road. The southern most of <br />these features does da;~light in the access road cut between <br />' approimately stations 6+50 to 7+90. The base of the northern <br />most of the two landslide lobes stops short of the access road <br />cut. <br />' 4;ith regard to the existing landslide features, our mapping would <br />indicate that they have regressed up the slope to a point wr:ere <br />they are nox impinging upon exposed bedrock materials at the <br />' surface. It is our opinion that t?~ey will likely undergo no <br />further headword migration. Therefore, we feel their impact in <br />terms of dis*_urbed aria will not get significantly greater o•;er <br />time. F'urL-her, in cor.sidaring the nature of the existing slid_s, <br />' The Railroad Stacion • 555 E. Pikes Peak Avenue. Suite 107 • Colorado Springs, Colorado 80903 • (303] 634-1999 <br />