PERMFILE49764

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 4.05 HYDROLOGIC BALANCE
• Media Type: D
• Archive: Yes

1
4.05.8 Acid-forming and Toxic-forming Spoil
Acid-forming materials do not exist within the overburden to be removed
by the mining operations. A discussion on the overburden at the Colowyo
operation has been conducted as set forth in Section 2.04.6. A
discussion of the overburden monitoring plan is set forth in Section
2.05.
4.05.9 Permanent and Temoorar~Impoundments
Colowyo intends to construct a number of small depressions on reclaimed
areas. These small depressions are essential and basic to the management
of the rangeland post-mining land use of livestock grazing and wildlife
habitat. The design of the depressions provides for structures having a
vertical height less than five feet from the bottom of the channel to the
bottom of the spillway and impound less than two acre feet of water. As
such they are exempt from Division of Water Resources, Office of State
Engineer requirements. water harvesting ditches may also be used to
enhance the function of the depressions, which is consistent with
practices employed on adjacent rangelands. The location of the
depressions is shown on Map 12 - Hydrology - South and other information
is provided in Exhibit 7, Item 16 Small Depressions/Tanks.
The depressions collect surface runoff from precipitation events and
snowmelt from reclaimed areas. The depressions do not result in the
diminution of the quality or quantity of water for downstream water
users. Colowyo is the holder of water rights immediately downstream.
During periods of low precipitation the impoundments may be dry, which
is consistent with regional practices on similar rangelands. Since the
source of water is surface runoff from revegetated areas the quality of
the water will meet the requirements of the intended use.
The depressions have areas of 4h:ly slopes or less to provide easy access
to both livestock and wildlife. These depressions and any associated
ditches, while intended to be permanent, will be classified as temporary
until the requirements of Rule 4.05.9. are met. Prior to construction,
all designs are submitted to the Division. A copy.of_the_as=built design
information will be submitted after construction for inclusion into
Exhibit 7, Hydrology. In addition, sedimentation ponds that are
subsequently approved as part of the post-mining land use, as shown on
the Hydrology - South Map (Map 12), will remain as permanent impoundments
after the requirements of Rule 4.05.9 have been met.
All embankments, impoundments and associated structures will be
revegetated if construction materials are conducive to plant growth.
Routine inspections of these structures will also be conducted
• 4.05-8
s~,~mea 7- i • y 9
r~. i~1 R -