PERMFILE57005

• Permit No: C1980005A
• IBM Index Class Name: Permit File
• Doc Date: 5/20/2005
• Section_Exhibit Name: Tab 7 Hydrology
• Media Type: D
• Archive: Yes

A pumping test was conducted at a Seneca II-W production well
completed in the Trout Creek Sandstone. The results of this
test provide a transmissivity of 23.3 ft2/day and a hydraulic •
conductivity of 1.8 ft/day. Stewart (1983) describes the Trout
Creek Sandstone as having a transmissivity of 1 to 2,800
ftz/day and a hydraulic conductivity of 0.006 to 4 ftJday.
Data obtained from the U.S. Geological Survey (Stanley G.
Robson, written communication, 1987) indicate that hydraulic
conductivity values for the Trout Creek Sandstone have a random
spatial distribution and a geometric mean of 5.1x103 ft/day in
the Twenty Mile Park area.
As the discussion above indicates, the aquifers underlying the
Seneca II leasehold are low yielding and cannot be ccnsidered
important regional aquifers (see Figure 7-2 for a comparison of
aquifer properties and well potential). Wells completed in
these strata can be expected to produce only very small
quantities of water for domestic or livestock use. In most
cases, drilling depths make it infeasible to complete livestock
or domestic wells in the deeper formations. As discussed •
earlier, poor water quality also limits ground water use in the
mine area.
It should be noted that due to the low yielding nature of
aquifers in the Seneca II area, the majority of aquifer tests
performed were some variation of a slug or bailer test. Since
these tests stress a relatively small volume of the aquifer,
transmissivity and hydraulic conductivity values discussed
above probably reflect conditions immediately near the well
bores.
3. Recharge Capacity
In addition to changing the ground water regime, mining of the
Seneca II site will also temporarily change infiltration rates.
Table 7-16 gives a summary of infiltration rates of various
soil types before and immediately after mining. These nwnbers •
7-50b Revised G4/30/90