Laserfiche WebLink
• EXHIBIT I - SOIIS INFORMATION <br />Soils of the Dowe Flats project area were mapped by the U.S. Soil Conservation Service in 1975 <br />as part of the Boulder County Soil Survey. The three main units mapped in azeas that will be <br />disturbed by mining include LaPorte very fine sandy loam, Manvel loam, and Gaynor silty clay <br />loam (Exhibit I Map). <br />The LaPorte soils are shallow and well rained, developing over limestone and limy shale. They <br />are possessed of moderate permeability, but because of their shallowness have low <br />water-retention capacity. The upper horizon on the Dowe Flats site is a dark brown sandy loam <br />from 4 to 7 inches thick, somewhat thinner than described in SCS (1975) where the upper <br />horizon was described as 8 inches thick. Underlying is a layer of pale brown calcareous loam <br />about 4 inches thick. Depth to pazent material varies from 11 to 13 inches. These soils are <br />present much as mapped, except where they extend into azeas mapped as Gaynor (see below); <br />thickness of the A horizon has varied from 4 to 10 inches. <br />Manvel soils aze deep and well-drained, developing on calcareous, loamy alluvium. <br />Permeability in this soil is moderate and in conjunction with the great soil depth, water holding <br />• capacity is low. The upper layer is a brown loam about 6 inches thick. The underlying layer <br />is a pale brown loam about 14 inches thick. Below this, a dazk grayish brown to dazk brown <br />silty clay loam extends to about 60 inches. This soil covers the broad central azeas of Dowe <br />Flats, away from limestone outcrops and away from the slopes of Rabbit Mountain. <br />The Gaynor soils are moderately deep soils derived from loamy alluvial and wind-blown <br />materials. They are mapped in areas expected to have been the site of wind-deposits, sites rather <br />difficult to predict exactly. Much of the azea mapped as Gaynor is either LaPorte or Manvel <br />series. The surface layer is a grayish brown silty clay loam about 6 inches thick. Below this <br />is a brown silty clay loam about 4 inches thick. The underlying layer of silty clay loam extends <br />another approximately 20 inches deep. <br />Soil samples have been submitted to the Colorado State University Soils Laboratory for analysis <br />to verify reclamation suitability. Slight modifications to the boundaries of soil units have been <br />made but aze not considered critical because all material is anticipated to be rated as suitable for <br />revegetation, and all units are likely to be salvageable to similaz depths. <br />• <br />