Laserfiche WebLink
2.06 <br />2.06.8 Surface Coal Mining and Reclamation Operations on Areas, or Adjacent to <br />Areas, Including Alluvial Valley Floors. <br />The portion of the permit area planned to be disturbed consists of colluvial <br />material resulting from mass wasting and erosion of the adjacent Mesaverde <br />formation. As erosion occurred, fractured sandstone, siltstone and shale <br />rocks moved by overland flow and gravity across the Mancos Shale <br />formation which underlies the lower area of the planned disturbance. <br />Due to the high elevation of the area of planned disturbance, subirrigation of <br />the area is not possible. In fact groundwater required for local domestic use <br />is not available within the upper portions of the unconsolidated colluvial <br />deposit. <br />Reconnaissance conducted of this site's specific geology and surface land <br />forms within the permit and adjacent area resulted in the identification of an <br />alluvial valley floor in the North Fork Valley below the site where surface <br />mining operations are proposed. The extent of ground identified as alluvial <br />valley floor is shown on Map 24, Alluvial Valley Floor, presented in Volume II. <br />The alluvial valley floor is present in the adjacent area. The North Fork of the <br />Gunnison River lies in stream laid sediments. The relationship of the permit <br />area with this alluvial valley floor is insignificant in that no disturbance to the <br />alluvial valley floor will occur. Since the valley was settled in the early <br />1900's, the alluvial valley floor has been cleared to accommodate flood <br />irrigation from water provided by the upland Deer Trail ditch and Fire <br />Mountain canal which divert water from Hubbard Creek and the North Fork of <br />the Gunnison River, respectively. The lower area of planned disturbance <br />occupies a terrace of colluvial material substantially above the stream laid <br />deposits of the North Fork of the Gunnison River. <br />The DRMS, through its initial permit adequacy comments, has indicated the <br />mine operation could possibly raise salinity levels in the Colorado River <br />Drainage Basin. The means of which, originates from spring snowmelt and <br />precipitation - related percolation through the site disturbance to the alluvial <br />valley floor and the North Fork of the Gunnison River. <br />PR -14 2.06-2- 03/14 <br />