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Moro and Associates, LC <br />• Quaternary Landslide Deposits <br />In many locations where the shales and mudstones of the Mesaverde Formation exist on <br />unstable, steep, wet slopes, landslides are common (Plate 1). These landslides can be up to <br />100 to 200 feet deep and several hundred fee[ wide and long. Many landslides appear to be <br />related to soil water, which saturate the near surface material. Springs are commonly <br />observed emanating from the toes of the landslide deposits. Field investigations indicate that <br />both older landslides and very recent major landslides have occurred. <br />Quaternary Alluvial Deposits <br />Extensive alluvial deposits are not present over most of the Wes[ Elk Mine lease area. These <br />deposits are limited primarily to the valley of [Ite North Fork of the Gunnison River. Thinner <br />• alluvial deposits are present beneath many of the small stream drainages throughout [he lease <br />area. The alluvial deposits consist of interbedded sands, gravels, and clays. <br />3.3.2 Structure <br />Bedrock in the West Elk Mine lease area generally dips 3° to 5° toward the northeast. <br />Locally, the rocks dip more steeply due to rolls that are the result of differential compaction <br />of soft sediments. South of the lease area, bedrock dips as great of 30° occur where [he <br />sediments have been uplifted by the Mount Gunnison Massive. The West Elk Mine lease <br />area generally does not contain folds or faults with large displacements. However, <br />significant fracturing has occurred. The major fracture orientations are north-south and east- <br />west, whereas the minor fracture orientations are north 30° east and north 50° west. Many of <br />. the surface drainages may be fracture controlled (Intrasearch, 1993 and 1994). Most of the <br />Characterization of Groundwater Systems in the V icinity of the West Elk Mine, Somerset, Colorado <br />29 January 1999 <br />Page 21 <br />