PERMFILE47451

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Exhibit 51 Lower Refuse Pile
• Media Type: D
• Archive: Yes

Mountain Coal Company, L.L.C. Exhibit 51
West Elk Mine ~ Lower Refuse Pile
majority of the remaining dissolved solids consist of sulfate, chloride, or bicarbonate anions. The total
•. dissolved solid concentration of [he leachate is approximately 700 mg/I and is 300 times lower than [he
theoretically calculated allowable leachate concentration. It should be noted that the calculation of the
allowable leachate concentration is provided to gain a perspective on the maenitude of leachate impacts and
not [o advocate an acceptable leachate quality. The comparison of the measured leachate qualih• with the
calculated allowable leachate quality shows that less than one percent of the stream loading capacity (the
difference between the existins concentration and [he ISS) is used by dischar=ine leachate into the North
Fork when consideringthat the actual amount of dilution will probably be I OO~times greater than has been
assumed in the calculations.
Arsenic, boron, cadmium. chloride, maneanese. nitrate. lead, selenium, and zinc leachate concentrationsare
below or within a factor of approximately 2 of meetin, the ISS without any dilution and therefore are not
anticipated to cause any water quality degradation in the North Fork. Copper appears to have the largest
impact on a percentage basis, using approximatel}• 10% of the available loading capacity for the
conservative assumptions employed in this analysis. The remaining metals and elements, even those which
were not measured durine the leach tests, are expected to have similarly neglieible impacts to the North
Fork on the basis of the over one thousand fold dilution provided by the river.
Ammonia was not measured during the leaching tests but is not expected to leach from the refuse. Table 6
of the CDMG published Guidelines for the Collection of Baseline Water Oualitv and Overburden
Geochemistry Data, published in 1982. providesjustification of the required monitoring parameters. That
document states that ammonia is "a major component of ammonium-nitrate explosivescommohly used at
surface mines in the western U.S.". West Elk Mine is an underground mine anddoes not use explosives as
part of its production mining procedures, nor is ammonia a natural occurring component of the refuse and
therefore it is not expected to be present in the refuse pile leachate. Refer to Exhibit 56 of the MRP for a
report of leachate analysis conducted prior to the construction of the B seam slopes.
5.4.4 Water Quality of the North Fork of the Gunnison River
The Notch Fork of the Gunnison River is currently considered a Class 1 cold water aquatic habitat and a
Class II recreational stream. The water is used downstream for both potable water and agriculture. ISSs
have been set by the Colorado Department of Natural Resources (1984) and can be found in Appendix I.
Section 2.05.6 of the MRP discusses the Probable Hydrologic Consequences from the West Elk Mine, and
in particular, the projected impacts of the LRP on surface water and ground water. Specifically, a mass
balance of salinity contribu[ionsto the North Fork has been calculated, and includes potential contributions
from the LRP.
Selected water quality data obtained by the USGS and MCC were reviewed to estimate the water quality of
[he North Fork during low flow periods. The data reviewed consisted of 1 ~ sampling events conducted by
the USGS during water year 1982, quarterly sampling conducted by MCC in October of 1985, and
graphical representationsof the data for 1983 (see Appendix I). The lowest flow volume in [he tiorth Fork
normally occurs behveen October and February. Water qualih• data obtained for the remaining months
during which flows are generally in excess of 100 cfs were not reviewed for the purpose of this analysis.
Water quality for most parameters in the North Fork is eenerally boner during periods of low flow than
during high flow because of lower turbidity during low flow. Typical values for the average low flow data
were estimated and are given in Appendix I. Most parameters are below the ISS during low flow periods.
• Ammonia is typically found at a concentration of about 0.1 S mg/I in comparison with the ISS of 0.2 mg/I.
The measured concentration of ammonia occasionally exceeds the ISS both upstream and downstream of
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