2007-10-22_PERMIT FILE - C1981014A ‎(5)‎

• Permit No: C1981014A
• IBM Index Class Name: Permit File
• Doc Date: 10/22/2007
• Section_Exhibit Name: 4.05 Hydrologic Balance
• Media Type: D
• Archive: Yes

• The Magpie Creek permanent diversion will be designed to ensure dynamic
equilibrium with the overall drainage system. Geomorphic
characteristics of the proposed diversion will be similar to the
original Magpie Creek channel with similar flow gradients, and a
similar cross-sectional configuration. Given the relatively arid
climate of this area, there is no significant aquatic habitat in any
of the major drainages in the mine or adjacent areas. However, changes
in vertical alignment within the diversion channel corresponding to the
natural terrain, along with placement of rip-rap or other erosion
control materials where required to prevent channel erosion, will
result in development of a series of riffles and pools.
Portions of the Magpie Creek diversion channel bottom which are not
riprapped will be stabilized utilizing revegetation measures described
in Exhibit 19. Areas disturbed during reconstruction of the channel,
that are above the channel freeboard elevation, will be revegetated
utilizing the reclamation seed mixture presented in Table 33, Proposed
Temporary and Permanent Seed Mixtures and Seeding rates. This seed
• mixture includes a variety of native and introduced grasses and forties
which will result in establishment of an effective vegetative cover to
stabilize areas adjacent to the diversion channel.
4.05.5 SEDIMENT CONTROL MEASURES
Sediment control measures for the Southfield operations have been
designed to meet or exceed the more stringent of applicable State or
Federal effluent limitations. Primary sediment control measures include
grading, topsoiling and revegetating disturbance areas to control
runoff and increase infiltration. Use of localized sediment control
measures including mulching, erosion netting, sediment fences, check
dams, sediment traps, straw bales and other means as appropriate, use
of collection and diversion ditches where necessary to intercept and
route runoff flows, and use of sedimentation ponds to retain runoff and
allow suspended solids to settle-out prior to discharge to natural
drainages. Major sediment control structures for the Southfield min and
loadout areas are shown on the Mine Area Surface and Groundwater
• Hydrology Map, (Map 12), Loadout
4.05-12 Revised 7/24/01
Technical Revision No. 32