2024-05-21_PERMIT FILE - C1981010A (8)

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seams. N pit has been designed as a strikeline pit and will utilize a combination of truck and loader stripping, dozer stripping, and dragline stripping (in a strikeline orientation). This pit will start to the west and advance to the east, reworking old areas of Ashmore Pit. N Pit will be one of four active pits during the 2023 – 2027 permit term, along with L pit, I pit and J pit. Highwall mining may take place on both the north and south sides of the box-cut , in the L, M and Q seams . The seams may be high wall mined from the bottom seam (Q seam) up (to the L seam). See section 3.1.4.2 Highwall Mining for a description of the highwall mining. Colt Pit Mining Area C Pit is located in East and West Buzzard drainages. This area was previously mined as dip-line dragline pits until the overburden became too deep. Mining in the Colt pit was completed in September 1992. Future pit development of C Pit was proposed in PR-11 and would have laid on the edge of the previously mined C Pit area. A strike-line box cut would have beeen dug along the previously mined C Pit area where both L and Q will be conventionally mined from the box cut, as well as with highwall mining methods. This pit will not be developed now, however, topsoil stripping for a portion of the pit was completed in the summer of 2023 and will be replaced accordingly. 3.1.4.2 Highwall Mining Highwall mining has occurred on a limited basis to the east of East Ashmore pit. In 2007, the H seam on the floor of cut 45 was highwall mined eastward from this pit. In the future, highwall mining will be conducted in the end walls or highwalls/low walls of the I, J, L, and N pits. In I Pit the F seam will be mined to the north of the strike cut and in J Pit the G2 seam will be mined to the north, thus complying with rule 4.23.2 (1). In the East Ashmore pit (northern L Pit) wall the H seam will be mined. In the L dip pit wall the K and/or the M and/or the Q seam will be mined. In N Pit, the L, M, and Q coal seams will be mined. The HWM areas in L pit are less than 2,000 feet in length, therefore, they comply with 4.23.2 (1). The N Pit length of box cut is 4,200 feet, with a potential to HWM mine seams to the north and the south of the surface pit. Coal on either end of the pit will remain for future access as described under 4.23.2 (1) (b), meaning the access panels will be 4,200 feet apart for N Pit. Use of Mining Technologies’ HW H800 Addcar System or a similar system is planned. A launch vehicle platform, which sits on the floor of a conventionally mined cut, controls all functions of the system, rigid conveyor cars, which are each fitted with their own belt conveyor, are fed by a full sized conventional, remote controlled underground continuous miner. Video cameras placed on the miner give real time feedback to the outside operator, a proprietary HORTA Guidance System gives continuous three- dimensional locations, and Gamma Sensors in the miner’s cutting head provide the ability to sense roof and floor rock and help keep the miner in the coal seam and avoid dilution from the roof and floor. Depth of penetration and coal recovery will vary depending on coal seam splitting, thinning or pinching, coal quality, roof and floor integrity, and machine physical limitations. Penetration depths of up to 1,600 feet are possible under optimal conditions; however, with Trapper’s thin and steeply dipping coal seams much shorter penetrations are anticipated, (1,200 feet are shown). Trapper is not currently aware of any abandoned or active underground mine workings in any of the pertinent coal seams in the proposed highwall mining areas. In the event abandoned or active underground mining operations are identified, no highwall mining will be conducted within 500 feet of any underground workings in the applicable seams. A protective buffer of 200 feet will be left in place between the north wall of the old F Pit and the southernmost extent of the N Pit south highwall mining. Trapper is also not aware of any dwellings, buildings, tanks, impoundments or utilities overlying areas planned for highwall mining. Subsidence is not anticipated with any highwall mining activities at the site. Design criteria established by Agapito Associates Inc. (Summary of Geotechnical Design and Operational Considerations for Highwall Mining-I, J, N and L Pits, Trapper Mine; January 2, 2020; Page(s) 3-1, 6-3), will be utilized to ensure long-term stability of highwalls and mining areas based on seam and overburden thickness. 3-15b