PERMFILE56529

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Exhibit 48 Drainage Modifications
• Media Type: D
• Archive: No

J

Wesl Elk Coal Company, Inc.
Posl Olfice Box 591
Somerset, Colorado 81434
Telephone [phone]
June 13, 1986
Mr. Robert Liddle
Colorado Mined Land
1313 Sherman Street
Denver, CO 80203
Dear Bob:
Reclamation Division

As you are aware West Elk Coal Company (CMLRD Permit
C-007-80) has been having maintenance and operational
problems with the infiltration underdrain dewatering
system installed in sediment ponds MB-1 and MB-2.
This problem causes no environmental problems; however,
it causes maintenance and operational problems because
the ponds require pumping occasionally. WECC plans
to correct this problem by installing a gate valve
in the control tower of each pond near the pond bot-
tom elevation. Necessary reinforced concrete wing
walls as well as a baffle to keep sediment from
entering the valve area will also be installed. This
valve will not interfere with the normal dewatering
outlet located in the tower. The lower valve will
be equipped with a manually adjustable height skimmer
consisting of a flexible rubber or other suitable hose
to maintain the discharge above the sediment level of
the ponds. See attached drawings for detail.
During precipitation events the normal dewatering
outlet will be used to dewater the 10 YR, 24 HR
precipitation event runoff as required by the regula-
tions.
The installation of the lower valve is a maintenance
item being performed in lieu of repairing the under-
drain system. Repair of the underdrain system is
extremely costly and the effectiveness and reliability
of the underdrain system due to design considerations
is very poor.
The enclosed drawings (revised) are located in the
N~+CO-610a