2012-01-17_REVISION - C1996083 (3)

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2.05.3 Retaining Wall Concrete retaining wall located at the B- Bench. The 8 -foot high retaining wall is approximately 50 -feet long. Hubbard Creek Shaft See Map 39 for the location of the ventilation shaft that was constructed during 2007 and 2008. It is lined with steel and has a finished diameter of 10.5 feet. The steel liner was cemented in place. Prior to drilling, the perimeter of the shaft was grouted to minimize water infiltration. Grouting was extensive in the collar area and was reduced when the shaft alignment encountered solid rock. The shaft was blind bored the entire depth of approximately 500 feet. The cuttings removed from the shaft are considered underground development waste and were therefore hauled to one of the approved gob disposal areas. The Hubbard Creek shaft has been backfilled and capped. Terror Creek Shaft See Map 42 for the location of the ventilation shaft site that was constructed during 2010 and 2011. The drill site was constructed from an existing pad that was used to drill monitoring well TC- 03 -03. The drill site was upgraded with gravel surfacing. The cut slope of the drill site was retained with approximately 5300 FSF of soil nail retaining wall. The shaft will be raise bored its entire depth of approximately 550 feet. The perimeter of the shaft will be grouted to minimize water infiltration. Grouting will be extensive in the water bearing zones. The cuttings from the raise bore will be conveyed to the outside and placed in the coal mine waste disposal area. The shaft will be lined with concrete and have a finished diameter of 18.5 feet. A ventilation fan is not required for the shaft since pressure from the mine ventilation system will force air out the shaft. The shaft will be equipped with an escape hoist and nitrogen generator. The electrical powered compressors needed to run the nitrogen generator will be fed by an underground power cable. BRL will need frequent access to the site to test the escape hoist. Emergency Escape System During 2009 the Operator installed an emergency escape system over the Hubbard Creek Shaft. The hoist is 20 -feet long, 8 -feet wide and 9 -feet tall. The hoist foundation consists of six 5.5' X 5.5' 16" thick spread footings with 4 -foot tall 18 -inch diameter piers. The head frame has a 20 -foot square base, is 3 -feet by 12 -feet at the top and is 27 -feet tall. The head frame will be bolted to the existing shaft collar. The emergency escape system has been removed. A similar emergency escape hoist will be installed over the Terror Creek Shaft. Filter Building A pre- engineered metal building designed to house a filter system to clear the water obtained from the Deer Trail Ditch. The filter building is adjacent to the pump house which is located along the Deer Trail Ditch. The building is approximately 40 feet by 16 feet with an 8 -foot eave height. MR -128 2.05 - 21 - 01/13/12