Laserfiche WebLink
that dragline mining would not be the only viable mining method for the K Pit due to the <br />relatively steep dip of the coal seams and overburden. Trapper proposed to mine the K Pit as a <br />truck/loader operation and with a dragline. A dragline opened the first pit in the K Pit area along <br />the upper ridge. Dragline spoil was cast into the area of the Horse Gulch Fill. After the first cut, <br />a truck/loader fleet was used to continue excavation of the K Pit. The truck /loader fleet was <br />used to strip the L seam and a dragline or dozer excavated to the R seam with a dipline <br />orientation and progressing into the L Pit. Trapper selected this method based on safety <br />considerations and potential for recovering coal that would otherwise have been lost. Trapper <br />believes the truck/loader mining method will result in a reclaimed landform that meets the <br />requirements of approximate original contour, and provides for long-term stability of the area. <br /> <br />Strip Pits <br /> <br />Trapper will mine coal from the following four pits during the 2013-2017 permit term: Ashmore <br />East Pit, Kimber (K) Pit, L (f.k.a. G Pit) Pit and M Pit. Pits advance generally east and <br />southward. The maximum length and width of a cut varies from pit to pit (see section 3.1.4.1 of <br />the permit for details). In 2002, D pit progressed to the point that it merged with E Pit. This <br />combination D/E Pit is approved for ash disposal. A (Ashmore) Pit remains open for ash <br />disposal (see description of ash disposal below). <br /> <br />The Ashmore East Pit was primarily mined with a dragline until 2003 and further stripping was <br />conducted in this area in 2006 and 2007. Further advances in this pit are projected to occur in <br />the 2013-2017 permit term. The eastern portion of K Pit is mined in a dipline orientation with <br />the truck/loader fleet continuing to uncover the upper coal seams to the L seam ahead of the <br />draglines. The draglines then expose the M, Q, and R seams. The L Pit is designed as a <br />strikeline and dipline pit and will use both truck and loader crews as well as dragline equipment. <br />M Pit will be a continuation of L Pit on the same dipline orientation of advancement. M Pit is <br />located outside of the landslide area and that is the only distinction from L Pit. <br /> <br />Removal of Topsoil and Overburden <br /> <br />Prior to disturbance, and in advance of the pits, brush is cleared and topsoil is removed and <br />salvaged. Topsoil is stockpiled only if a live-haul replacement area is not available in the area. <br />If stockpiled, piles are shaped and seeded to establish vegetation for protection from wind and <br />water erosion. After topsoil removal, the overburden is drilled and blasted in advance of the pit. <br />Overburden is then stripped by draglines, scrapers, truck/loader teams or bulldozers. Finally, <br />front-end loaders load coal into 90-ton haul trucks, which deliver the raw coal to the Craig Power <br />Plant. <br /> <br />Trapper removed 24.6mm BCY of spoil material in the K Pit and placed the material in a <br />permanent excess spoil fill that is known as the Horse Gulch Fill. Additional spoil from the K <br />Pit is also placed within the pit to meet the requirements of the post-mine topography. Much of <br />this overburden was located within the landslide that occurred in K Pit in October 2006. The <br />Horse Gulch fill was nearly completed at the end of the 2007-2012 permit term. The only <br />is located downslope from the Horse Gulch Fill is <br />Horse Gulch sediment control pond. An underdrain was constructed beneath the Horse Gulch <br />Fill. <br /> <br /> <br />19 <br /> <br />Trapper MineJuly 9, 2013 <br /> <br />