2006-12-11_REVISION - M1994005 - Laserfiche WebLink

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t 1 1 f ~ ~ United Companies, Inc. liareh 21, 1994 Page 2 Based on drill log data provided, ten drilled holes were spaced at approximately 400 feet on centers. The logs indicate 1 to 4 feet of fine grained overburden soils over the silty sand, gravel and cobble (pit run) material. Drill holes extended to a depth of 25 feet with no ground water being encountered. The drill holes did not extend Lo a depth that encountered the underlying Mancoa shale. Par soil series maps the fine grained overburden soils classify as Vernal clay loam, 0 to 2 percent slopes for the portion to be mined and Uncompahgre loan for the northeast coiner, approximately 4.3 acres that will not be mined. The Vernal clay loam (VeA) consists of a reddish brown clay loam overlying coarse sand, gravel and cobblestones. The clay loam has a slow permeability and a moderate organic content. The clay loam is generally 18 to 20 inches thick. The lower sand, gravel and cobblestones have high pezmeabil ity, are not highly susceptible to erosion and the structure is stable. t The Vncompahgra loam, 0 to 2 percent slopes, ie a flood plain and low terrace soil. The upper a to 30 inches is a loam followed by stratified .sand, silt and clay lenses and layers, Followed by the sand, gravel and cobbelstones encountered at this site. 1 i 1 1 The sand, gravel and cobbles are classified in geologic terms as Quantarnary sediments which includes river deposits, landslide deposits and rock glaciers or ice-Age glncial debris. Other geologic maps indicate the overburden materials ae simply flood plain deposits, primarily sand and gravel with significant fines. Vnderlying the flood plain gravel (Quanternary sediments) is the lSancos shale formation. The Nancos shale formation is from the upper Cretaceous age and is made up of grey to yellow, marine deposits. The Mancoa shale was laid down in Plat layers in a Cretaceous sea, the shale is now tilted up south ward toward the Colons Pit November 06 S-6