PERMFILE133432

• Permit No: M2003091
• IBM Index Class Name: Permit File
• Doc Date: 1/16/2004
• Doc Name: Stability of Irrigation Ditches and other Structures.
• From: DMG
• To: DMG
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
7313 Sherman 6t., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: January 16, 2004
TO: Erica Crosby
FROM: Allen Sorenson~~
RE: Stability of Irrigation Ditches and other Structures,
Lafarge West, Inc., Duckworth Pit, File No. M-2003-091
OLORADO
(VISION O F
IN&RALS
EOLOGY
]LAMATION•MINING
SAf ETY•SCIENCE
Bill Owens
Governor
Creg E. Walther
Executive Director
Ronald W. Cottony
Division Director
Natural Resource Trustee
The Duckworth Pit permit application describes minimum mining setbacks from permanent martmade
structures in three different ways within the body of the application exhibits; these descriptions appear
to be in conflict and must be resolved prior to permit application approval. Exhibit S to the application
commits the Operator to setbacks equal to 3-times the depth of the gravel pit, and includes an additional
50-foot buffer of un-mined land on either side of waterways, Idaho Creek and the Smith and Emmons
Ditch in particular. The following cross sections illustrate the permit conditions described in Exhibit S
for the mining setbacks.
Generic Structure.
Could be a fence,
shed, road, etc.
Face
Depth
(a) Setback to Structures if Operator Mines to a Vertical or near Vertical Pit Wall,
1
Un-Excavated Native Material
(not backfill)
(b) Operator may Mine to a Vertical Pit Wall as Illustrated in Cross-Section (a), but must Mine at 3:1 once
Inside the Zone where the Horizontal Distance to [he Structure is less than 3 Times the Pit Depth.
Depending on the Nature of the Structure and the Excavating Methods Employed, a Small Un-Mined
Buffer at the top of the 3:1 Slope maybe Required.
Office of Office of Colorado
Mined Land Reclamation Active and Inattive Mines Geological Su