PERMFILE107555

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 12/5/2005
• Section_Exhibit Name: Tab 17 Probable Part 2
• Media Type: D
• Archive: No

estimate assumes that all Seneca II-W South area pit-inflow waters will discharge to Dry Creek
without infiltration losses to the alluvium. It should be noted that pit inflows that are routed
directly to the surface water system will only continue while the South area is being mined.
After the coal seamis) are mined out and reclaimed, the water will become spoil seepage. It is
anticipated that the Wadge seam will be mined out in 2003, while the Sage Creek and Wolf
Creek seams will be mined out in 2010 and 2011, respectively.
Impact of Spoil Water Quality on the Ground and Surface Water Quality
This section addresses impacts to ground water and surface water quality from spoil discharge
within and adjacent to the permit-expansion area. The following discussion is divided into five
subsections: overburden characterization; the controls on spoil and downgradient water quality;
water chemistry and flow inferences based on Seneca II-W South monitoring results; potential
impacts of replaced spoil on ground water quality; and potential impacts of replaced spoil on
surface water quality.
Regional and site-specific hydrogeologic data were collected and analyzed to assess the
presence of acid-forming or hazardous materials and their potential effects on ground water and
surface water chemistry. Downgradient and downstream water uses were evaluated to
determine the potential effects of underground and surface spoil water discharges on domestic
and agricultural water uses in the adjacent areas. Since mining has only recently been
conducted in the Seneca II-W area, there are no site-specific spoil water or spoil spring data
available from the area. Therefore, as with the existing permit's PHC for Seneca II-W, spoil
chemistry data obtained at the Seneca II Mine will be utilized to assist in the impact analysis.
Overburden Characterization
Daia for the Wadge seam mining area overburden characterization were compiled from 15 cores
collected from within the Seneca II-W mine area and 4 cores collected from within the Seneca II-
W South expansion area. The Seneca II-W overburden cores include 30-C, 42-C, 43-C, 99-C,
125-C, 300-C, 311-C, 508-C, 555-C, 569-C, 609-C, 1127-E, 1128-E, 1129-E, and 1130-E. The
four Seneca II-W South overburden cores are labeled 217C, 286C, 3080C and 3152C and are
shown on Exhibit 6-6A. SCC has no core overburden analyses from the Sage Creek/Wolf Creek
mine area.
However, a well nest containing five monitoring wells (WSOV24, WSC24, WWCOV24, WWC24
and WWCU24) was drilled in August 2001 approximately 1,600 feet down dip of the proposed
Sage Creek/Wolf Creek mining area. During drilling, overburden chip samples were collected
from the Sage Creek overburden (WSOV24), Wolf Creek overburden (WWCOV241 and Wolf
Creek underburden (WWCU24).
The Seneca II-W/Seneca II-W South Watlge core and Sage Creek/Wolf Creek monitoring well chip
samples were used to assess the overburden characteristics in the Seneca II-W South mine area.
Analyses included acid base potential IABPI, which describes the buffering capacity of a
material, expressed as tons of calcium carbonate ITCaCOa) required for the complete
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