GENERAL30475

• Permit No: C1981019
• IBM Index Class Name: General Documents
• Doc Date: 5/4/2007
• Doc Name: Proposed Decision & Findings of Compliance for PR2
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

prepared by Leonazd Rice Consulting Water Engineers' study (LRCWE). The report concluded that
there was an absence of ground water from the site (see Exhibit 7A of the Permit). In addition, 17
test holes were drilled and their corresponding records collected when the property was originally
explored. All well data confirmed that where water was encountered, it was limited both vertically
and laterally and encountered under perched conditions. For further information on the well test data,
see pages 2.04.7-5 and 6 of the PAP.
There is little development of the ground water resource in the local area. The few wells that have
been completed in the Williams Fork interbedded sandstones yield less than five gallons per minute
and their uses aze limited to domestic and/or livestock use. Nearby residents haul drinking water
supplies from Craig and Meeker.
Saturation of the Williams Fork sandstones is weak to nonexistent, with the flow controlled by the
geologic structure of the Collom Syncline in a down dip direction. Ground water direction follows
the geologic structural trend and flows to the northeast. Following the down dip direction, where the
ground water flow meets the land surface, infrequent discharges from the Williams Fork formation
are seen as seeps and springs on the valley walls of Goodspring and Taylor Creeks. Further analysis
of the Goodspring and Taylor Creek basins show the rechazge rate to be 0.2 to 0.35 inches per yeaz
from the Williams Fork surface outcrop area (PAP, page 2.04.7-11). Annual precipitation varies
from year to year, and due to topography and elevation changes, varies even across the permit azea.
Precipitation averages 21.5 inches (PAP, Page 2.04.7-1), but has been recorded at less (12.45 to 18.6
at the Permit area during 1978-1980) (PAP, Table 7, page 2.04.8-11).
The Iles Formation, of varying thickness, is located beneath the Williams Fork Formation (and the
coals to be mined). The Trout Creek Sandstone, a regional aquifer reaching thickness of up to 75
feet, is located within the Iles Formation. The Trout Creek sandstone is fine, well sorted, calcazeous,
and is a continuous unit that can be correlated over a large area. It is mainly from this sandstone
member that the two creeks on the permit area, Goodspring and Taylor, receive their flow. The Trout
Creek Sandstone is believed to contain water due to a saturation zone found beneath Goodspring
Creek. The recharge areas for the sandstone are south of the permit area in the higher elevations or
where the Trout Creek sandstone is exposed at the ground level and subsequently has been eroded
above the Goodspring Creek elevation.
Hydraulic conductivities of the sandstones below the coal seams to be mined are variable but low,
with average transmissivity of 40 gallons per day per foot. Little water is recharged, transmitted or
discharged from the permit area. Drawdown analysis of two wells, Taylor No. 1 and No. 3, both
drilled into the Trout Creek Sandstone, showed an average transmissivity of 40 and 260 gallons per
day per foot and hydraulic conductivity of 3.4 and 0.13 gallons per square foot, respectively. Porosity
and permeability characteristics ofthis aquifer were not calculated due to the depth of the sandstone
and lack of corresponding data from other locations within the Iles Formation. Storage coefficient for
one well, Taylor No. 1, was 0.066, but should only be considered a factor for that well and not the
Iles Formation as a whole since no reference data is available.
Proposed Decision and Findings of Compliance 4 May 2001
Permit Revision 02 Page 39