2006-08-28_REVISION - M1977424 - Laserfiche WebLink

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Permit M77-424 Amendment 1 EXHIBIT I SOILS INFORMATION Exhibit I Page 1 of 4 Soils information is provided in Exhibit I of the original mine permit and supplemented in this exhibit. The original permit identified 7 soil associations in the Logan Wash Mine and Logan Wash areas that are related to geographic sub-settings related to altitude, vegetation, slope aspect, and geology. However, the most recent soil survey completed by the Natural Resources Conservation Service was used to describe soil types for this exhibit. Therefore, discrepancies between soil type names can be attributed to the new terminology contained in this most recent survey (Natural Resources Conservation Service, 2005). In addition to the information provided in Exhibit I of the original permit, data presented by the Natural Resources Conservation Service (MRCS) online website available at (http://soildatamart.nres.usda.gov/Default.aspx) and Web Soil Survey available at (http://websoilsurvey.nres.usda.gov/app/) were used to create the soils map specific to the affected area and to supplement the original permit information (see Exhibit C Sheet 2, Vol. 2). According to the NRCS, there are 9 different types (within 6 different map symbols) of soil within the affected azea associated with the water transmission pipeline and evaporation pond. Information presented on the NRCS website concerning the rangeland productivity of each of the 9 types of soil affected by the water transmission pipeline and evaporation pond show a considerably high suitability of topsoil for the establishment and maintenance of plant growth. The NRCS summarizes the total dry-weight production of each soil type with values given for unfavorable, normal, and favorable years of production. The Barx soil type (map symbol 3) shows a total dry-weight production range of S00 to 1,000 pounds per acre from unfavorable to favorable yeazs of production respectively. Map symbol 7, consisting of the Biedsaw and Sunup soil types show a range of 200 to 450 pounds of dry-weight production per acre. The Dominguez soil type (map symbo132) shows adry-weight production ranging from 500 to 900 pounds per acre, and the Happle soil type (map symbo144/46) shows adry-weight production of S00 to 1,000 pounds per acre. Map symbol S6 shows 1,500 to 3,000 pounds per acre dry- weight production for its Pazachute member, 500 to 1,200 pounds per acre for its Irigul member and 1,500 to 3,000 pounds per acre for its Rhone member. The Tosca soil type (map symbo167) shows adry-weight production range of 1,400 to 2,500 pounds per acre. Suitability of topsoil for the soil types is evident at the water transmission pipeline and evaporation pond sites. Successful surface reclamation of the water transmission pipeline and of the constructed surface at the evaporation pond has occurred with the native soils available. Native plants have reestablished themselves in the affected aeeas and show healthy rates of growth and self-maintenance without the need for supplemental