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is secondary permeability and is the result of groundwater flow through <br />the fractured and weathered portions of these strata. The fractured rock <br />acts as a conduit to the surface colluvial aquifers. The third type of <br />inflow is also due to secondary permeability and it is the result of <br />groundwater flow along fault zones. These fault zones may be in contact <br />with surface aquifers with water bearing zones in the overburden, or with <br />deep-seated sources of groundwater. The streams courses in the North <br />Fork may be fault controlled and thus could be a source of recharge for <br />fault related inflows. Prior to the construction of the mine entries, <br />piezometers were installed in the colluvial/landslide strata immediately <br />upslope of the entries. All piezometers but one were destroyed during <br />construction of the entries. <br />The operator at the West Elk Mine expects that mine inflows will <br />increase at a rate slower than the McWhorter mode] predicted for <br />advancing mine workings. Most of the inflow has occurred along the <br />subcrop in the same location each year. The inflow is seasonal and varies <br />with the magnitude of seasonal precipitation. The experience neaz the F <br />Seam subcrop and in the Mayo report indicates that the colluvium, coal <br />and bedrock are recharged locally. In prior yeazs, inflow to the advancing <br />mine workings has been minimal and unmeasurable. However, In Mazch <br />1996, MCC experienced a large inflow of water in the B East Mains <br />while mining through afault/fracture system. In April 1996, MCC <br />encountered the same fault in a subsequent entry, the inflow was <br />estimated to be a maximum of 2,500 gpm. The flows have since receded. <br />In May 1996, the flow was measured at approximately 240 gpm and had <br />diminished to less than 100 gpm by December 1998. <br />Three of the five entries experienced inflows during construction, which <br />began in September of 1981. Adit entry No. 4 experienced the greatest <br />inflow, about 5 gpm, which decreased to less than 1 gpm and dried up <br />within a week. The No. 1 entry produced a small quantity of water from <br />the bottom of the coal at a rate of less than 1 gpm and dried up within <br />two weeks. However, the sandstone roof at entry No. 1 was dry. Entry <br />No. 5 produced drips, approximately 0.1 gpm, for about one week. The <br />other two entries were dry. During the period from August to December <br />1981 water levels dropped in some of the piezometers located above the <br />portals. In all cases the drop was not greater than two feet. Water levels <br />have changed very little since January 1982. <br />MCC has submitted two plans for the sealing of the portals upon closure <br />of the mine. The first plan calls for sealing the portals to allow gravity <br />discharge of mine inflows. MCC anticipated, from water samples taken <br />in the Oliver Mine, that mine waters will not be toxic. This plan calls for <br />the construction of a block wall at the portal and afour-inch PVC pipe to <br />drain the collected mine waters. The second plan is contingent on the <br />mine producing toxic mine waters. This plan calls for the construction of <br />52 <br />