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Kimber Pit Mining Area <br /> <br />The October 2006 landslide in the East Panel of Trapper Mine resulted in a dramatic change in planned <br />mining methods at the mine. K Pit and L Pit (a.k.a. G Pit) were originally planned as dragline pits, consistent <br />with Trapper’s historic mining method. After extensive geotechnical study and mine planning efforts, it was <br />determined that dragline mining was not a viable mining method for the K Pit due to the steeply dipping <br />structure. <br /> <br />After the East Panel landslide, Trapper retained Agapito Associates, Inc. (AAI) to perform geotechnical <br />investigation of the area to determine the causes and ramifications of the event. Numerous studies and <br />evaluations were performed by AAI personnel. A detailed analysis of AAI’s findings is available in AAI’s <br />January 2008 report, “Trapper G-Pit Landslide Mining Assessment” found in Appendix T. <br /> <br />K Pit was mined with both a truck/loader fleet and draglines. The western portion of the pit was mined in a <br />strikeline orientation. The truck/loader fleet strips the overburden from the upper coal seams (to L seam) <br />ahead of the dragline operations. Seams M, Q, and R were exposed with the dragline operation. <br /> <br />The eastern portion of K Pit was mined in a dipline orientation with the truck/loader fleet continuing to <br />uncover the upper coals to L seam ahead of the draglines, and the dragline operations exposing M, Q, and <br />R seams. <br /> <br />Due to the steeply dipping pit floors, the initial overburden removed from K Pit was placed in the Horse <br />Gulch Fill and as final pit backfill in Flintlock pit. K Pit has been reclaimed and is in various stages of bond <br />release. <br /> <br />Lancaster Pit Mining Area <br /> <br />L pit has been designed both as a strikeline and dipline dragline pit over the years. Development of this pit <br />occurred as mining progressed from K Pit, and will utilize a combination of truck and loader pre-stripping, <br />dozer stripping, and dragline stripping (in a dipline or strikeline orientation). L Pit will be one of five active <br />pits during the 2023-2027 permit term, along with C, I, J and N Pits. <br /> <br />Hawken Pit Mining Area <br /> <br />Mining in Hawken pit (H-pit) was completed in April 1997. After performing reclamation activities, the Queen <br />Anne dragline walked to Ashmore pit in May 1997. <br /> <br />Ithaca and Jennings Pits Mining Area <br /> <br />I & J Pits are single seam pits that are opened to the F and G2 seams, respectively, by a combination of <br />truck and loader pre-stripping and dozer stripping. Both of these pits are opened in relatively shallow cover <br />(50 to 80 feet) along the outcrop of the seams, and both are located in the No Name, Coyote and Buzzard <br />Drainages. I & J Pits will be two of five active pits during the 2023 – 2027 permit term, along with C, L and <br />N pits. Highwall mining may take place in these pits on the F and G2 seams from the pit box-cut area to <br />the north. See section 3.1.4.2 Highwall Mining for a description of the highwall mining. <br /> <br />Nighthawk Pit Mining Area <br /> <br />Nighthawk Pit (N pit) is located in the East and Middle Pyeatt drainages. This pit is being developed in the <br />same area as historical mining of the Ashmore Pit. The Ashmore pit mined to the two uppermost seams in <br />the area: H and I seams. N pit is being developed in the same area but will be mining the L, M and Q <br />seams. N pit has been designed as a strikeline pit and will utilize a combination of truck and loader stripping, <br />dozer stripping and dragline stripping (in a strikeline orientation). This pit will start to the west and advance <br /> <br /> <br /> <br />3-15a <br />