Laserfiche WebLink
2-45 <br />graben is saturated. For the purposes of analyzing probable hydrologic impacts, it is assumed that <br />the seam will be saturated. <br />Mining did encounter water as the mains were advanced to the east. These flows occurred <br />while the mine was progressing downdip in the East Mains. The flows have ranged from a <br />calculated low of less than 1 gallon per minute to a high of 7.72gallons per minute in 2000. The <br />amount of water flowing into the mine was calculated from water use records and may not be <br />precise. The flow was higher when mining was occuring to the east and have tapered off since <br />mining ceased to the east. <br />The area that was being mined in the graben appeared to contain a perched aquifer that <br />received recharge from both groundwater and surface water. This area in the graben exhibited a <br />significant fracture system resulting from the geologic processes involved when the graben was <br />formed. It can be expected that this fracture system contributed to the amount of water that was <br />present in the seam because of increased porosity and may have allowed increased migration <br />because of increased permeability. <br />As mining progresses to the east and north, inflows of water contained within the coal seam <br />could once again occur. Figure 2.2-1 shows that the area to be developed in the saturated portion of <br />the seam will be significantly larger than the area that was developed in the graben. This area <br />should not have the well developed fracture system exhibited in the graben. Migration of in-seam <br />water may be reduced, but the increased area that will be effected could more than make up for the <br />reduced <br />Mc Volume 1 October 17, 2001 <br />