2011-02-14_REPORT - C1981018 (2)

Home Browse Search

1 2010 Hole Plugging All plugging activities were overseen by Blue Mountain Energy, Inc. Engineering Dept. staff. Return Shaft #3 (RS -3) On November 1, 2009 RS -3 was permanently sealed by backfilling from the bottom to the surface with soil previously stockpiled on site. Cook's Trucking provided the equipment and operators to perform this task. The portion of the steel liner projecting above the surface was then cut flush with the concrete pad and a 6+ inch concrete plug was poured on the top. In early 2010 an apparent bridge in the filling gave way allowing significant settling to occur. The shaft was again backfilled to within 12 feet of the surface. A temporary concrete slab was placed over the hole to restrict access. In July a 12 foot permanent plug of concrete was poured in the top of the shaft. Cook's Trucking provided the backfilling operation. White River Aggregate provided the concrete on July 15, 2010. Return Shaft #4 (RS -4) In the spring of 2010 RS -4 was backfilled with 50+ feet of non - combustible fill and capped with a 6 foot concrete plug. We later returned and backfilled the shaft to within 8 feet of the ground surface. The surface casing was cut even with ground level and the remainder of the shaft backfilled with concrete forming a permanent plug on July 15, 2010. LWB10 -1, LWB10 -2 On July 15, 2010 these degas boreholes were backfilled their full depth with concrete from White River Aggregate. Monitoring Well 32 -7M In August, monitoring well 32 -7M was backfilled with six 80 lb. bags of mortar mix mixed with six 50 lb. bags of sand. 20 gallons of water were used to mix the material before pouring down the hole. Fourteen 80 lb. bags of concrete mix mixed with 30 gallons of water were placed between the surface casing and the 32 -7M well pipe. Well 32 -7U, which shares the hole with 32 -7M, was temporarily capped to allow this backfilling. Cementing was stopped before the top of 32 -7U was reached. Monitoring Well 32 -71L Monitoring Well 32 -7L had been initially plugged with two 50 lb. bags of Baroid 'Holeplug' on February 1, 2001 prior to mining through the well casing. The top of the plug was tagged at 385'. The top of the coal seam was at approximately 400'. Since this well no longer serves a useful purpose and poses a potential leak to the sealed mine, plugging was completed in August 2010 by placing ten bags of mortar mix mixed with ten bags of sand mixed with thirty gallons of water. The surface annulus between the 2"