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Longwall mining experience gained from the mining of the No. 5 Mine will be used, and may result in minor changes <br />to the mine plan for the No. 6 mine. It is anticipated that overall extraction in the longwall areas will exceed 80 <br />percent, considered to be very good recovery for an underground coal mine. <br />Utilization of longwall equipment for coal extraction allows complete extraction of the coal within the working limits <br />of the machine. Geological structure may limit face height and maximum equipment height, (i.e. strong cleats, rider <br />seams, sandstone channel margins). The only coal not recovered in a longwall mining operation is the coal left in <br />barrier pillars, or roof and floor coal that is outside the cutting range of the shearing machine. Barrier pillars will be <br />retained in the No. 5 and No. 6 mines for: <br />• Protection of Main Entries <br />• Property Boundary Barriers <br />• Outcrop Barriers <br />• Subsidence Barriers <br />Protection of Main Entries. Previous site experience indicates that protective barrier pillars of approximately 200 feet <br />are adequate to provide the necessary protection for the main entries. If conditions indicate that greater or less <br />protection is required, MCM will adjust the width accordingly. Main entry barriers along Big Bottom will also be <br />sized to protect AVF areas and the Yampa River. <br />Property Boundary Barriers. Property boundary barriers will be retained to assure that the subsidence angle of draw <br />does not cross the permit boundary, and that mining will not occur closer than 50 feet from an adjacent owner's <br />property line. <br />Outcrop Barriers. Barrier pillars with a minimum width of 100 feet will be retained between the coal workings and <br />the coal outcrop. The outcrop barriers are necessary to minimize the subsidence effects along the outcrop, serve to <br />keep the mine ventilation system intact, and prevent the extraction of oxidized coal along the outcrop. <br />In areas where daylighting occurs, the area will be prepared in the following manner. Topsoil, if available, will be <br />stripped, stockpiled, and stabilized with the approved topsoil stockpile seed mixture. The area to be disturbed will be <br />approximately 200 feet X 400 feet, with the topsoil stockpile, overburden stockpile, and daylighted entries contained <br />in the area. If the daylighting occurs in favorable field conditions, an area will be excavated around the entry. In <br />unconsolidated material, the slope will be 2H:1V and in consolidated material about 0.25H:1V. A continuous miner <br />will then daylight into the prepared area. If daylighting occurs in unfavorable field conditions, the continuous miner <br />will daylight and the site will be prepared as described above when conditions allow. When this situation arises, an <br />area of 20 feet X 25 feet will be disturbed prior to site preparation. <br />The daylighted entry will be fenced to keep large animals out. Adequate warnings signs will be placed around the <br />site(s) to alert the public the entry are part of a mining operation. These daylighted entries will be incorporated into <br />the mine ventilation plan. The daylighting procedure described above is a general plan and MCM will submit a minor <br />revision to the Division prior to undertaking any daylighting. The minor revision request will be submitted when the <br />mining unit is within 100 feet of daylighting. <br />Subsidence Barriers. Although the need for subsidence barriers is not anticipated until mining occurs under critical <br />structures or features, MCM plans to protect the State Highway 13 from subsidence as indicated on the Life -of -Mine <br />Plan Map (Map 22). This will be done by leaving pillars in place, in addition to limiting mining so that the highway is <br />outside of the angle -of -draw. Current estimates of angle -of -draw as well as experience gained from mining operations <br />will be used to help design the subsidence barriers. Further information on subsidence and subsidence effects on <br />renewable resources is provided later in this section. <br />The projected annual production from the No. 5 Mine was approximately 2.5 million tons, while the projected <br />production of the No. 6 Mine, under an active production scenario, is approximately 4.0 million tons annually. <br />Economic and marketing constraints will generally dictate total annual production. The anticipated annual production <br />from the mines for active operations is presented on Table 53, Annual Coal Production. <br />TR14-36 2.05-5 Revised 03/10/14 <br />