Laserfiche WebLink
West Elk Mine <br />Five observation wells, which were drilled above two adjacent longwall panels on Cambria, <br />Pennsylvania, were monitored. Samples of wellwater were collected before and after mining <br />progressed through the area. "This study shows that (a) the observed changes in groundwater <br />chemistry did not affect the potability of the water..." (Matetic and Trevits 1992). <br />Water Stored in Sumns <br />A summary of events leading up to the decision to store lazge volumes of water in large capacity <br />sumps within the mine can be found in the previous section entitled Groundwater Quantity Effects. <br />The following section describes how, due to the unexpected inflows from the BEM and 14HG <br />Faults, previously mined NW longwall panels aze used to store water volumes which exceed the <br />hydraulic capacity of the current treatment facilities. These panels will be used for storage to <br />optimize the mine water treatment system. There aze also plans to use the NE and Box Canyon <br />Panels sealed sumps for storage of water in the same manner. <br />A distinct difference in the fault inflows and other "typical" mine inflows is water temperature. <br />Typical mine inflows aze about 68°F to 72°F, and the fault inflows were approximately 84°F and <br />88°F, for the BEM and 14HG Fault inflows, respectively. A comparison of the BEM Fault <br />water with both "typical" groundwater quality in the B Seam is provided in Table 54. These <br />Tables demonstrate the similarity in water quality and show that the fault water can meet MCC's <br />NPDES discharge requirements without treatment, including the applicable temperature <br />requirements. <br />• A description of the difficulties treating water containing a previously un-encountered colloid and <br />the treatment processes attempted aze discussed in the previous section entitled Basis for Large <br />Capacity Sump Use. While the source of this unusual colloid is not definitively known, MCC <br />believes that the clay particles may be inherent in the coal seam in the eastern part of the mine. <br />In recent yeazs, mine dischazges through the existing treatment ponds have demonstrated an <br />increase in alkalinity and conductivity (TDS). At the present time it is uncleaz what is causing <br />the increase in TDS but it appears to be associated with mining rather than any change in <br />groundwater chemistry. Ongoing investigations aze under way to further assess the potential <br />cause for these chemical changesAcid-Base Potential of Roof and Floor Samples from the B <br />Seam, ESeam, and FSeam in the Permit Area <br />The Acid-Base Potential (ABP) is a measure of how effectively the neutralization potential <br />(alkalinity) present in solid samples will neutralize the acid producing potential of the sample <br />resulting from sulfur present as sulfide (pyritic sulfur). Total sulfur may be used to represent the <br />move conservative, maximum potential acidity. The ABP represents the amount of calcium <br />carbonate (CaCO3-equivalent that is present in excess of the amount needed to neutralize the acid <br />potentially produced from oxidation of sulfur in the sample. The ABP (in tons of CaCO3-equivalent <br />per 1000 tons of material) is calculated from: <br />ABP = (neutralization potential) - (31.25)(wt% pyritic sulfur or total sulfur). <br />• <br />2.05-290 RevisedJ~me 2005 PR/0; Rev. March 2006; Rev. May 2006 PRl0 <br />