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The Hubbard Creek vent shaft was blind drilled to a 14 -foot finished <br />diameter. The shaft was steel lined to a finished diameter of 12 -feet. The <br />500 foot deep shaft was grouted through water bearing zones. To prevent <br />surface drainage from entering the shaft, the concrete collar was extended <br />above the ground surface. During idle periods, a screen is placed on the top <br />of the concrete shaft. Because of the method of shaft construction, there <br />was no measurable water inflow during shaft construction. The pre -grouting <br />and shaft liner were effective in stopping groundwater from entering the <br />shaft. There is no flow at the bottom of the shaft. <br />The Hubbard Creek vent shaft has been backfilled a capped with concrete. <br />This backfill will protect the integrity of the grouted liner to contain the water <br />bearing zone. The concrete cap will ensure no surface run-off will enter the <br />backfilled shaft. Thus, the shaft backfill and concrete shaft will protect the <br />hydrologic balance. <br />The Terror Creek shaft was raise bored. The shaft was ring grouted prior to <br />construction. The ring grout was effective in the near elimination of water <br />inflow to the shaft. <br />The quality of ground water that comes in contact with coal seams and <br />surrounding strata is generally degraded. Bear Coal Company prepared a <br />study of the potential effects of mining on the B -Seam aquifer (J. E. Stover & <br />Associates letter to DMG dated October 23, 1995). A correlation was made <br />between the geochemical characteristics of the roof, coal and interburden <br />and the degradation of the quality of water in the coal seam. Soluble <br />calcium, magnesium and sodium appears to degrade the quality of ground <br />water that comes in contact with the disturbed coal seam and surrounding <br />strata. This degradation of ground water quality is considered typical for <br />water which seeps into the mines in the Paonia Somerset area. <br />The quality of springs and seeps should not be degraded by the coal mining <br />operation. As explained in Section 2.04.7, the primary source of water for <br />the springs are unconsolidated quaternary deposits. These deposits should <br />not be affected by the mine operation to the extent that the quality of the <br />spring water would be degraded. <br />PRA 4 2.05-107 03/14 <br />