2020-12-23_PERMIT FILE - C1981044

• Permit No: C1981044
• IBM Index Class Name: Permit File
• Doc Date: 12/23/2020
• Section_Exhibit Name: 4.0 Permanent Performance Standards
• Media Type: D
• Archive: No

4.05.2 WATER QUALITY STANDARDS AND EFFLUENT LIMITATIONS
The plan far protection and control of drainage and sediment as described in Section 2.05.6 provides that surface
drainage from the disturbed area within the permit area will passed through sedimentation control structures. All ponds
will be constructed and maintained to safely contain the volume of a 10-year, 24-hour precipitation event. The quality of
water and accumulation of sediment in the ponds will be monitored periodically. In addition, grab samples of water will
be collected from the pond and their discharge measured to determine their effectiveness in meeting the applicable
Colorado Water quality standards.
Discharge from the mining area, after treatment in sedimentation ponds, is not anticipated to exceed the effluent
limitation of Colorado agency requirements. Baseline ground water quality is discussed in Section 2.04.7, Hydrology
Information.
4.05.3 DNERSIONS AND CONVEYANCE OF OVERLAND FLOW AND SHALLOW GROUNDWATER
FLOW, AND EPHEMERAL STREAMS DRAII~IIIVG A WATERSHED LESS THAN ONE SQUARE MILE
The drainage and sediment control plan described under Section 2.05.6 provides for temporary diversion of surface
drainages within the permit area. A system of temporary ditches, as shown on the Drainage and Sediment Control Plan
Map (Map 26), will collect and route runoff within and around disturbed areas. Specifications for all temporary diversions
within the permit area are presented in Exhibit 18, Drainage and Sediment Control Plan.
The temporary diversions will have the purpose of reducing contribution of suspended solids to mnoff and diverting
undisturbed drainage from the mine area. The diversions will be constructed with a minimum gradient to pass the design
flaw and will be revegetated with grasses. Upon completion of mining and at the appropriate point mandated in the Coal
Regulations of the Colorado Mined Land Reclamation Board, the temporary diversions will be reclaimed as required in
Section 4.05.3(5).
None of the diversions will drain surface mnoff into underground mines.
4.05.4 STREAM CHANNEL DNERSIONS (RELOCATION OF STREAMS)
There will be no stream channel diversions at EC.
4.055 SEDIMENT CONTROL MEASURES
Sediment control measures to be implemented are shown on the Drainage and Sediment Control Plan Map (Map 26). These
facilities, consisting primarily of diversion ditches and sedimentation ponds, are located, constructed, and maintained to
minimize erosion and increased contribution of sediment load to runoff. Discussion of the drainage and sediment control is
presented under Secfions 2.05.3 and 2.05.6. The design parameters and calculations for the sedimentation control structures
are found in Exhibit 18, Drainage and Sediment Control Plan.
As necessary, facilities to control sediment will be installed in areas above or below the planned sites of disturbance.
"Upstream" facilities, such as temporary diversion ditches and check-dams upslope from the mining activities will divert
mnoff away from the disturbed areas or divert the mnoff into sediment ponds.
4.05.6 SEDIMENTATION PONDS
The location of all sedimentation ponds, is shown on the Drainage and Sediment Control Map (Map 26). The designed
plans and specifications for the sedimentation ponds are presented in Exhibit 18, Drainage and Sediment Control Plan. All
sedimentation ponds are located as close as practical to the areas to be disturbed. Other methods of sediment control will be
located on the areas to be disturbed. These methods include the use of contour furrowing or terraces.
Permit Revision 04-34 4.01-4 Revised 7/2/04