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<br /> <br /> <br /> <br />PR-04, Colowyo Coal Mine C1981-019 20 August 2016 <br /> <br />3.2.6 Climate <br /> <br />Climatic information is found in Section 2.04.8 of Volume 1 of the PAP. The region is <br />characterized by a semi-arid steppe climate regime. Precipitation averages 18 inches per year <br />with a significant portion of this yearly precipitation occurring as snowfall. Prevailing winds <br />over the permit area are from the southwest and average eight to nine miles per hour. High winds <br />are not common, due to the protection afforded by local terrain. <br /> <br />3.2.7 Soils <br /> <br />Soils information is found in Section B, Item IV of this document, as well as in Section 2.04.9 <br />(Volume 1) and Exhibit 9 (Volume 3) of the PAP. Soils information associated with the South <br />Taylor and Lower Wilson expansion areas is included in Section 2.04.9 of Volume 12, Exhibit 9 <br />of Volume 13, and Maps 5A, 5B, and 5C of Volume 14. Soils information associated with the <br />Collom expansion is found in Exhibit 9, Item 8 (Volume 19) and Map 5D (Volume 22). <br /> <br />The most prevalent soils within the proposed Collom disturbance area are the Duffymont-Nortez <br />complex. The Duffymont soil ranges from 6 to 20 inches available for topsoil salvage, and is <br />formed in slope alluvium and colluviums over sandstone bedrock. Nortez soils tend to be deeper <br />and are found in the loess deposited over alluvial materials. Salvageble depths for Nortez soils <br />range from 20 to 40 inches. The Thornburgh-Lithic Haplocryoll soil complex is found on <br />steeper side-slopes. The Thornburgh series tends to be poorly developed, with 12 inches or less <br />potentially available for topsoil salvage. <br /> <br />3.2.8 Ground Water Hydrology <br /> <br />Groundwater information is found in Sections 2.04.5, 2.04.7 (Volume 1 for the East Pit, West <br />Pit, Section 16 Pit, Facilities Area and Gossard Loadout, Volume 12 for South Taylor, and <br />Volume 15 for Collom expansion) and Exhibit 7 of the PAP and in Colowyo’s Annual <br />Hydrologic Reports. Groundwater in the permit area occurs in beds of fractured sandstone and <br />coal that are laterally discontinuous and in isolated alluvial aquifers. CCC refers to alluvial <br />water-bearing units in the Collom area as “valley fill”. Base flow in the four perennial streams in <br />the general area (Good Spring Creek, Wilson Creek, Collom Gulch and Jubb Creek) comes <br />mainly from groundwater discharge from alluvial aquifers in the stream valleys. <br /> <br />The Trout Creek Sandstone is the principal regional aquifer in the area. It is approximately 450 <br />feet beneath the lowest coal seam to be mined in the Collom area (Gb). The principal recharge <br />area for the Trout Creek Sandstone is in the outcrop belt on the north slope of Wilson Dome, <br />south of the permit area. In addition to the considerable vertical separation, the Trout Creek