Laserfiche WebLink
ENVIRONMENTAL ASSESSMENT <br /> backfilled. Outlet protection erosion control would be installed at the pipe outlets in both locations. The <br /> diversion would remain until the backfilled channel could be re-established with appropriate erosion <br /> protection. Due to the limited size of the channel bottom (20-ft wide), the diversion should remain in <br /> place for less than a month. <br /> Topsoil would then be spread over the disturbed area up to the original soil depth and surface elevation, <br /> and the stream bed would be re-established as closely as possible to its original configuration. The re- <br /> established stream would be lined with HDPE liner to limit water infiltration, and the liner would be <br /> covered with a bedding layer overlain with riprap to prevent erosion of the channel. Construction of the <br /> low-cover crossing would take about six months and during construction up to approximately 10 acres <br /> would be temporarily disturbed and then reclaimed.The construction of the proposed low-cover crossing <br /> would meet the definition of Development found in the LPC Land Use Code and would be subject to the <br /> appropriate land use review process. <br /> From the ends of the arches on the west side of the Gulch, three inclines (i.e. tunnels angled upwards) <br /> would be developed by conventional mining methods up to where they would intersect the coal seam in <br /> the new lease area. From that point the coal would be mined utilizing the continuous mining method used <br /> in the existing King II Mine. <br /> 2.2.3 Reasonably Foreseeable Mine Operations <br /> Coal removal from the Project area would follow the conceptual mine plan shown in Appendix A, <br /> Figure 2-2. <br /> The type of mining utilized would be the "room and pillar" method followed by retreat mining. Though <br /> the thickness of the coal seam typically ranges from five to 10 ft, recoverable coal is restricted by four <br /> issues: 1) a minimum coal thickness of five ft; 2) a minimum roof thickness of 100 ft; 3) a maximum in- <br /> seam parting(i.e.a layer of rock in a coal seam)of eight inches;and 4)the quality expressed as BTU (British <br /> thermal units)value.The coal seam would be mined using continuous mining machinery. After the coal is <br /> mined, it would be brought to the existing surface facility via a conveyor and placed into one of two <br /> stockpiles where it would be crushed and prepared for transport. During normal underground mining <br /> operations, shale and sandstone break away from the roof and floor of the coal seam. This material is <br /> removed from the King II Mine,transported less than two miles (3.2 kilometers (km)) away and placed in <br /> the existing approved mine waste (refuse) storage area at the King I Coal Mine (Appendix A, Figure 2-1). <br /> Contents of the refuse pile, located in the vicinity of the closed King I Mine portal, include mine waste <br /> from the King I and 11 mines and is composed of coal, sandstone, siltstone, and carbonaceous shale rock <br /> fragments suspended in a sand, silt, and clay matrix (Trautner Geotech, LLC [Trautner], 2015). All mine <br /> refuse is contained within a constructed waste bank. Historical drainage in this area has been modified <br /> and engineered to facilitate separation between the refuse pile materials and sources of water.The coal <br /> mine waste (refuse) volume has increased approximately 5,000 CY per year. As of July 2016, <br /> approximately 174,000 CY existed. Anticipated refuse production from 2017 through 2040 is <br /> approximately 5,000 CY per year.The waste bank is currently designed to accommodate up to 1,000,000 <br /> Dunn Ranch Area Coal Lease by Application COC-78825 and Mine Plan Modification EA 2-6 <br />