2011-05-12_PERMIT FILE - M2011028 (2)

Home Browse Search

EXIBIT I - Soils Information Attached as Exhibit I, Pages I-2 through I-49 is a portion of the Bureau of Reclamation's Geologic and Construction Materials Design Data Report for Borrow Area B which is the same location of this Animas Glacier Gravel permit request. Additional information for this report is available upon request. From the Bureau of Reclamation Soil Report and previous experience mining the northern portion of the pit there may possibly be 1" to 3" of topsoil. Below the topsoil we expect to encounter an average depth of 7' of eolian clay which will be removed and stockpiled in overburden piles to be used to reclaim the land. Thirty two feet (321) of Glacier Outwash Terrace deposits is expected to be encountered below this upper eolian clay level. Another lower eolian clay level of 2' lies below the Glacier Outwash Terrace and will be stockpiled as overburden and reused to reclaim. Below the 2' of overburden lies 25' of Glacier Outwash Terrace deposit down to bedrock of the Tertiary Age Animas Formation (Ta) and estimated at a elevation of 6596 to 6623. The Durango office of the National Resource Conservation Service was contacted for information concerning soil types and maps. Attached as Exhibit I, Pages I-50 through I-58 are the La Plata County Area, Colorado soil types and map. The pre-mining soils are generally described as clay loam to gravelly-sandy loam. These soils are: Farfa clay loam, 1 to 3 percent slopes; Farfa clay loam, 3 to 8 percent; Ustic Torriorthents-Ustollic Haplargids complex, 12 to 60 percent slopes. Generally, the mesa top is covered with the two Falfa loam soils which are eolian material deposited on glacier outwash debris. Their potential for erosion is moderate. The steeper slopes are generally covered with the Ustic.Ustollic soils and also generally cover the glacial outwash materials along the edges of the mesa and the hazard of erosion is high. The estimated runoff coefficient before development and mining was 0.10 to 0.30. The estimated post-mining runoff coefficient will be 0.18 to 0.22. Additionally, in 1987, Nielsons, Inc., requested succession and expansion of an existing Wheeler Pit Permit No. M-79-168 which covers the same area of the Animas Glacier Gravel pit. The US Department of Agriculture provided Soil Test Data which is attached as Exhibit I-59 through I-61. Please note that WCA's proposed seed mix and fertilizer rates are attached in Exhibit E - Reclamation Plan and is the same as required on the Animas-La Plata project for the Bureau of Reclamation. Animas Glacier Gravel Pit Weeminuche Construction Authority EXHIBIT I - Page I- I