PERMFILE135173

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 3/25/2003
• Section_Exhibit Name: NH2 Section 2.04.7 Hydrology Description
• Media Type: D
• Archive: Yes

• The total volume of water that could be evapotranspired from the vegetation study is assumed to
be under ideal conditions. In reality the evapotranspiration rates are slightly less. In many areas
shallow soils and rock ledges restrict rooting depths and inhibit maximum plant growth, thereby
reducing ET rates.
Aquifer Characteristics of the New Horizon Mining Areas
Eleven aquifer tests were conducted within the New Horizon 1 leasehold, the proposed New
Horizon 2 mining area and the immediate vicinity. A wide variety of aquifer testing and analysis
techniques were employed because of the range of well yields and aquifer types. Aquifer testing
techniques include constant discharge tests (Theis, 1935; Neuman, 1975; and Cooper and Jacob,
1946); slug injection and withdrawal tests (Cooper et a1., 1967, and Papadopulos et a1., 1973);
modified slug tests (McWhorter, 1982); and specific capacity tests. Analysis techniques primarily
involve matching the drawdown of recovery data plots against theoretical type curves or tangent
lines defining the slope of the data. With the modified slug tests, data analyses included eithertype
curve matching or analytical solutions.
• Transmissivity and hydraulic conductivity values throughout and immediately adjacent to the New
Horizon Mine are low to very low. The overburden and underburden aquifers have the highest
values and the coal aquifer has the lowest transmissive properties. There is an approximately one
order of magnitude range in the transmissivity and hydraulic conductivity values for the overburden,
coal and underburden aquifers. This suggeststhatthereisahighdegreeofspatialvariabilitywithin
the aquifers. Storage coefficient for the various aquifers vary by four orders of magnitude. The
alluvial aquifer has the largest storage coefficient (10'Z) and the coal and underburden aquifers
average about 10-5. The spoils monitoring well (GW-N27) was completed in the fall of 1987. A
short term specific capacity and transmissivity test was conducted at the time of water quality
sampling at Well CW-N27. A K value of 40 ft/day was determined. This was the highest specific
capacity and hydraulic conductivity values for any of the aquifers measured in the spoils aquifer.
In summary, aquifer yields at the New Horizon Mine are very low. The better aquifers, in terms of
transmissivitiesgnd hydraulic conductivities, are the overburden and the underburden. Yields were
so low that constant discharge tests were only attempted on one alluvial, one overburden and one
• Revised 18 Aug 2003 2.04.7-11