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and posted with signs to prevent access into the entry and to identify <br />• the hazardous nature of the opening. These devices will be periodically <br />inspected and maintained in good operating condition. <br />Permanent Sealing of Underground Openings <br />When no longer needed for mining operations, all entries or other <br />openings to the surface from the underground mine will be sealed and <br />backfilled. Permanent closure measures will be constructed to prevent <br />access to the mine workings by people, livestock, fish and wildlife, and <br />machinery. <br />Because of the geologic nature of the coal seams, the slope of the <br />entries will be uphill at an approximate 1 percent slope; however, <br />special precautions will be made if any gravity discharge of water <br />occurs after the closure of the underground operations. Peerless <br />Resources, Inc. does not anticipate any major amounts of discharge, if <br />• any, from the permanently abandoned mine portals. <br />The abandonment procedures for the portal areas are as follows: <br />1. A seal will be placed on the portal entries to a point where <br />the overburden is at least 3 times the height of the coal <br />seam. This seal will be of reinforced concrete of at least 12 <br />inches thick and keyed 12 inches into the coal or to the rock <br />contact. Concrete will be reinforced with a mat of 1/2 inch <br />rebar 12 inches in each direction, each face. Grouting will <br />be used if necessary to provide a more uniform seal around the <br />coal or rock contact. <br />2. Earth fill will extend into each portal opening a distance of <br />at least 12 feet. <br />3. Exposed coal outcrop will be covered with a minimum of 4 feet <br />• of non-combustible earth material to protect against <br />spontaneous combustion. <br />2.05-23 <br />