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Temporary Sealing of Underground Openings <br />All mine entries will be permanently sealed as described below. <br />Permanent Sealing of Underground Openings <br />When no longer needed for mining operations, all entries to the surface <br />from the underground mine will be sealed and backfilled. Permanent <br />closure measures will be constructed to prevent access to the mine <br />workings by people, livestock, fish and wildlife, and machinery. No <br />water discharge is occurring from any of the Bear 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 <br />where the overburden is at least 3 times the height of the <br />coal seam. This seal will be of reinforced concrete of at <br />. least 12 inches thick and keyed 12 inches into the coal or <br />to the rock contact. Concrete will be reinforced with a <br />mat of 1/2 inch rebar 12 inches in each direction, each <br />face. Grouting will be used if necessary to provide a more <br />uniform seal around the coal or rock contact. <br />2. Earth fill will extend into each portal opening a distance <br />of at least 12 feet. <br />3. Exposed coal outcrop will be covered with a minimum of 4 <br />feet of non-combustible earth material to protect against <br />spontaneous combustion. <br />The procedures for permanent closure of the portal entries are shown on <br />Figure 3, General Specifications for Permanent Closure of Portal <br />Entries. <br />• <br />-20- <br />