2018-06-08_PERMIT FILE - C1981010A (3)

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Kimber Pit Minino Area The October 2006 landslide in the East Panel of Trapper Mine resulted in a dramatic change in planned mining methods at the mine. The K Pit and L Pit (a.k.a. G Pit) were originally planned as dragline pits, consistent with Trapper's historic mining method. After extensive geotechnical study and mine planning efforts, it has been determined that dragline mining is not a viable mining method for the K Pit due to the steeply dipping structure. After the East Panel landslide, Trapper retained Agapito Associates, Inc. (AAI) to perform geotechnical investigation of the area to determine the causes and ramifications of the event. Numerous studies and evaluations were performed by AAI personnel. A detailed analysis of AAI's findings is available in AAI's January 2008 report, "Trapper G -Pit Landslide Mining Assessment" found in Appendix T. K Pit is mined with both a truck/loader fleet and draglines. The western portion of the pit was mined in a strikeline orientation. The truck/loader fleet strips the overburden from the upper coal seams (to L seam) ahead of the dragline operations. Seams M, Q, and R were exposed with the dragline operation. The eastern portion of K Pit was mined in a dipline orientation with the truck/loader fleet continuing to uncover the upper coals to L seam ahead of the draglines, and the dragline operations exposing M, Q, and R seams. Due to the steeply dipping pit floors, the initial overburden removed from K Pit was placed in the Horse Gulch Fill and as final pit backfill in Flintlock pit. With mining complete, the K Pit is currently being backfilled and Is in the reclamation process. L_Pit Minino Area L pit has been designed as both a strikeline and dipline dragline pit over the years. Development of this pit occurred as mining progressed from the K Pit, and utilizes a combination of truck and loader stripping and dragline stripping (in a dipline orientation). L Pit will be one of two active pits during 2018, along with N Pit. Hawken Pit Minino Area Mining in Hawken pit (H -pit) was completed in April 1997. After performing reclamation activities, the Queen Anne dragline walked to Ashmore pit in May 1997. Ithaca Pit Minino Area There is no mining scheduled for Ithaca pit (1 -pit) during the 2013-2017 permit term. This area was originally projected to affect previously disturbed and reclaimed but unmined land. It was to be located on the northern fringes of the old Ashmore pit located in the Coyote and No -Name watersheds. Future development of this area is currently under consideration. Nighthawk Pit Minino Area Nighthawk Pit (N pit) is located In the East and Middle Pyeaft drainages. This pit will be developed in the same area as historic mining of the Ashmore Pit. The Ashmore pit mined to the two uppermost seams in the area: H and I seams. N pit will be developed in the same area but will be mining the L, M and Q seams. N pit will be designed as a dipline pit and will utilize a combination of truck and loader stripping, dozer stripping and dragline stripping (in a dipline orientation). This pit will start to the west and advance to the east, reworking old areas of Ashmore Pit. Future highwall mining may take place in this pit on the L, M and Q seams from the pit box -cut area to the west. See section 4.1.4.2 Highwall Mining for a description of the highwall mining. The only mining activities planned in N pit during 2018 are topsoil removal and haulroad construction. 3-15a Revision: -I'R - //I Approved: