REV01220

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 6/13/1994
• Doc Name: PN C-81-019 TR REQUEST WEST PIT AREA WATERSHED BOUNDARY CHANGES & ADDITION OF TWO DIVERSION DITCHES
• From: COLOWYO COAL CO LP
• To: DMG
• Type & Sequence: TR29
• Media Type: D
• Archive: No

TECHNICAL REVISION REQUEST FOR THE WEST PIT AREA
WATERSHED BOUNDARY CHANGES AND ADDITION OF TWO DIVERSION DITCHES
The enclosed SEDCAD hydrology modelling runs for the addition of
the West Pit Coal Road Ditch and the Temporary West Pit Ditch are
necessary to allow topsoil stripping to occur for the development
of the West Pit mining area.
Enclosed, please find a cover page, SEDCAD diversion ditch sizing
calculations, modelling map, and updated Hydrology South Sheet, Map
12. It is intended that May 12 should replace the same map found
in the Colowyo Permit C-81-019, and that the remaining information
should be a supplement to and placed immediately after the existing
West Pit Pond section in Volume 3, Exhibit 7 Hydrology Information,
Section 8, Design of Surface Runoff Control Structures.