2020-03-24_PERMIT FILE - C1981019A (2)

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RULE 2 PERMITS Once the overburden is sufficiently fragmented to allow for efficient removal and loading, overburden removal will commence. The location of the area to be mined is shown on the Mine Plan Map (Map 23A). Colowyo will utilize two distinct methods of overburden removal in the mining operation of South Taylor: (1) truck/shovel techniques and (2) dragline technique. By combining the use of both shovel and trucks, and draglines, Colowyo can both efficiently and economically handle the logistics involved in a multiseam, open pit coal mine. The truck/shovel operation will be used to open up the initial boxcut, and then will be generally utilized in removing overburden over the upper coal seams. In some areas of the pit the truck/ shovel will be utilized by taking all seams from the "X3" to the "G8" (X3, X4, B0, B1, B2, B3, C5, D1, D2, E2, F1, F6, F7, FA, FB, G7 and G8). In the dragline portions of the pit the dragline will generally uncover the "F6" through the "G8" (F6, F7, FA, FB, G7 and G8). From time to time, based on production requirements, truck/shovel or loader/truck methods may be utilized to assist the dragline operation in the lower seams. The overburden material is removed in a series of lifts or benches; the height of these benches will be influenced by the distance between the coal seams to be mined (see Map 24B, Mining Range Diagrams), and the equipment mining those benches. Overburden removal by the, truck/shovel method progresses on approximately 170-240 foot wide benches and has a maximum highwall height of about 60 feet. Electric shovels or front-end loaders load this overburden into 50, 170, 190 or 240 -ton trucks. The trucks then haul the overburden around the active coal pit and dump this material into the mined -out or stock pile areas. The truck/shovel operation will always precede the dragline operation in the multiple seam pits. A dragline will be used for overburden removal over the lower coal seams and the generalized multi -seam dragline sequence at the Colowyo operation is as follows: The dragline will begin the sequence by removing the overburden over the "F6" through the "FA" seams in a single sidecast mode, spoiling the overburden into the previously mined -out pit. The "FB" through the "G8" is removed from the spoil side of the pit. The spoil from the benching operation will be placed to allow the draglines sufficient room and adequate reach to remove overburden while operating on the spoil side. The draglines construct temporary ramps in order to walk to the spoil side. The "F6" overburden is first drilled and blasted, removed by the draglines, 76" coal is removed behind the advance of the draglines, then the drilling is initiated on the overburden of the 77" seam. This sequence is typical through the "G8" seam. With the dragline only mining through the F6 and below spoil, it will ensure that any suspect level spoil, based upon the suitability criteria, will stay in the bottom of the pit and will buried by a minimum of 50 foot of suitable Truck Shovel material. Upon complete removal of the overburden over the "G8" seam, the draglines walk around the end of the pit to the next cut to begin removal of the overburden over "F6" coal seam. No Special Handling Procedures will be required for the overburden in the South Taylor pit. The current overburden sampling program that will be used for the East Pit, West Pit, Section 16 Pit and the South Taylor Pit is described within Volume 1, Section 2.05. It was discussed between the Division of Reclamation, Mining and Safety (DRMS) and Colowyo that suspect levels of the Sodium Adsorption Ratio (SAR), Selenium (Se), Boron (B), Saturation % (Sat), and Molybdenum (Mo) need to be addressed in more detail to determine that Special Handling Procedures, that are outside the normal pit operational procedures, will not be needed in the South Taylor pit area. For this purpose, Colowyo will only use the South Taylor/Lower Wilson — Rule 2; Page 68 Revision Date: 4/7/17 Revision No.: RN -07