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The slope failure situated east of the Train Loadout Facility is most likely the result of a <br />combination of factors including groundwater perched over the claystone bedrock surface <br />and relatively steep topography. The existing slope situated between the conveyor and <br />railroad tracks is currently in an unstable configuration and stabilization/reconstruction is <br />necessary to provide long -term stability of the slope and to minimize further upslope <br />(southward) propagation. <br />NWCC recommends mitigation measures include: 1) regrading the failed slope to a 2 (H) <br />to 1 (V) or flatter configuration and 2) installation of a drilled pier retaining wall to the <br />north of the conveyor and access road. <br />A discussion of the geologic and geotechnical considerations related to the slope failure <br />and stabilization/reconstruction recommendations for the conveyor and access road are <br />outlined herein. <br />Purpose and Scope of Study <br />Conclusions <br />This report presents the results of a geotechnical investigation of the landslide (slide /slope failure) located <br />approximately 300 to 500 feet east of Train Loadout Facility at the Twentymile Mine in Routt County <br />Colorado. NWCC understands the slide /slope failure occurred earlier this spring /summer within the fill <br />slope situated between the railroad tracks and the coal conveyor belt. The approximate location of the <br />project site is shown on Figure #1. <br />A field exploration program was conducted to obtain information on subsurface conditions at the site. <br />Material samples obtained during the subsurface investigation were tested in NWCC, Inc.'s (NWCC) <br />laboratory to provide data on the classification and engineering characteristics of the soils and bedrock <br />materials. The results of the field and laboratory investigations are presented herein. <br />This report has been prepared to summarize the data obtained and to present NWCC's design and <br />construction recommendations for stabilizing the failed slope and existing conveyor structure, as well as <br />reconstructing the access road situated along the north side of the conveyor. <br />Job Number 11 - 3•1VI('(` Inc <br />P9OP 1 <br />