PERMFILE67811

• Permit No: M1988112
• IBM Index Class Name: Permit File
• Doc Date: 11/8/1988
• Section_Exhibit Name: EXHIBIT G WATER INFORMATION
• Media Type: D
• Archive: No

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~~' Based on the data available to date, the major dewatering
problem will be associated with the West Pit. It does not
' appear that significant water will be produced in the East Pit,
nor do there appear to be significant hydraulic problems
' associated with dealing with the East Zone. It is anticipated
that water encountered in the East Zone as it is bEing stripped
could simply be gravity-drained to a sump and pimped out of
i this area for use in the mining operation.
' Dewatering within the mine pit areas will include the
volume of natural precipitation which falls wil.hin the pit
areas. Based on data presented in Exhibit K, an estimated 15
' inches of rainfall can be expected annually in this area.
Therefore, as much as 160 ac-ftJyr may need to he collected
d di
d
f
an
spose
o
in the West Pit and approximately 30 ac-ft/yr
in the East Pit.

Upon completion of mining, the dewatering wells will
cease to operate and some inflow to the closed t~asin in the
West Pit may occur. The actual amount of inflow is dependent
on the areal extent of the West Pit ore zone aquifer. The
aquifer is expected to be of limited, local extent and the
proposed mining operation is expected to intercept most of the
aquifer. Inflows from the aquifer are not expected to be
significant.

Some water contribution from natural precipitation is
' also expected to the closed basin in the West Pit.
Precipitation in the project area is estimated at 15.3 inches
annually. Evaporation rates average 40 inches anrually.
' Based on the rate of evaporation and expected pit inflows
and precipitation, the West Pit is expected to be dry most of
the year. During the winter months and after large thunderstorm
' events, some short-term accumulation of water may occur in the
pit.
G-41
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