2023-07-14_PERMIT FILE - C1981010A

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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 five active pits during the 2023 – 2027 permit term, along with C pit, 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. C Pit will lie on the edge of the previously mined C Pit area. Most of the pit material is in-situ with some amount of spoil material that was graded over the top of the un- mined area (i.e. lower coal seams not previously mined). A strike-line box cut will be 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. A 150’ offset has been left between the old workings and new mine area to create a safety pillar for highwall mining activities. This pillar will exist along the south edge of C Pit. C Pit has been designed as a combination dragline/truck and excavator stripping pit. The pit will be broken up into approximately 3 sections, with the first section of the box cut being hauled to a temporary overburden stockpile located north of the pit. The temporary overburden stockpile will hold approximately 4,500,000 LCYs. Some truck/excavator material may be placed on the south side of the dragline spoil, on the south side of the box cut. C Pit will be excavated to L and Q seams. All available L and Q pit tons will be conventionally mined out of the box cut. Once all the pit tons are mined, highwall mining will be completed on all available Q seam. Material will be hauled from the adjacent cut block and placed into the open pit to backfill up to the L seam for highwall mining, only on the north side of the box cut. The temporary overburden stockpile will be used to backfill the final pit section and complete any other final reclamation. 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, C 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. In C Pit, the L and Q seam will be mined to the north. The south side of C Pit will consist of only Q seam highwall mining. 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 3-15b