2012-01-17_REVISION - C1996083 (3)

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MR -128 and shaft liner were effective in stopping groundwater from entering the shaft. There is no flow at the bottom of the shaft. The Hubbard Creek vent shaft has been backfilled a capped with concrete. This backfill will protect the integrity of the grouted liner to contain the water bearing zone. The concrete cap will ensure no surface run -off will enter the backfilled shaft. Thus, the shaft backfill and concrete shaft will protect the hydrologic balance. The quality of ground water that comes in contact with coal seams and surrounding strata is generally degraded. Bear Coal Company prepared a study of the potential effects of mining on the B -Seam aquifer (J. E. Stover & Associates letter to DMG dated October 23, 1995). A correlation was made between the geochemical characteristics of the roof, coal and interburden and the degradation of the quality of water in the coal seam. Soluble calcium, magnesium and sodium appears to degrade the quality of ground water that comes in contact with the disturbed coal seam and surrounding strata. This degradation of ground water quality is considered typical for water which seeps into the mines in the Paonia Somerset area. The Terror Creek vent shaft will be raise bored 550 feet deep to an 18.5 -foot finished diameter. The shaft will be Tined with nine inches of concrete. A geotechnical hole approved with MR -119 will provide hydro - geologic information regarding the depth and location of water bearing zones. This information will be used to design a ring grouting program to establish a grout barrier in the water bearing zones prior to construction of the shaft. To prevent surface drainage from entering the shaft, the concrete collar will be extended above the ground surface. During idle periods, a screen will be placed on top of the concrete shaft. Water inflows during shaft reaming will flow down the shaft to the underground workings. Additionally, after shaft construction is complete, flow at the bottom of the shaft will be monitored and results submitted to the DRMS on a monthly basis. The quality of springs and seeps should not be degraded by the coal mining operation. As explained in Section 2.04.7, the primary source of water for the springs are unconsolidated quaternary deposits. These deposits should not be affected by the mine operation to the extent that the quality of the spring water would be degraded. 2.05 - 101 01/13/12