GENERAL33664

• Permit No: C1980007
• IBM Index Class Name: General Documents
• Doc Date: 11/17/2006
• Doc Name: 2006 Award Nomination Memo
• From: Mike Boulay
• To: Sandy Brown
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203 C O L O R A D O
Phone: [phone] DIVISION o r
RECLAMATION
FAX: [phone] MINING
- &-
SAFETY
Bill Owens
Governor
Russell George
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
INTEROFFICE MEMORANDUM
TO: Sandy Brown

FROM: Mike Boulay `p
r l~i"
DATE: November 17, 2006
SUBJECT: West Elk Mine C-80-007, Methane Drainage Well Abandonment
For the past several years I have reviewed MCC's Annual Operating Plan which includes their
proposal for methane drainage well (MDW) drilling and abandonment. The drill hole plugging
method is in compliance with our recent guidance document: Installation, Operation, and
Abandonment of Coal Mine Methane Drainage/MonitorinQ Wells in Colorado. Specifically, MCC's
plan is compliant with our closure recommendation presented in the guidance document (fifty feet of
cement plug be placed at the lowest point inside the solid casing, above the perforated interval ofthe
well).
MCC has developed an innovative technique for ensuring that gas flow from the producing zone is
effectively sealed off and for ensuring that a cement plug can be placed at the lowest point inside the
well casing. MCC and their contractor (Lang Exploratory Drilling) have developed a rubber bridge
plug that is allowed to free-fall from the ground surface to its final resting point inside the well
casing. The rubber bridge plug then becomes the foundation for Hole Plug and subsequent
placement of approximately 100 feet of cement. This abandonment methodology is unique to
MCC's methane drainage well design. MCC utilizes telescoping casing with smaller diameter
casing at the bottom of the hole. The design is a cased hole completion with a floating perforated
casing below the solid cased portion of the well. The rubber bridge plug falls into place at the point
where the smaller diameter perforated casing begins just above the gas producing zone sealing off
gas migration potential. In many instances, the well casing is damaged (bent or cracked) from
subsidence due to retreat of the longwall panel. In these cases, the free-falling bridge plug is still
effective in that it falls into place to the lowest point possible in the well casing.
Office of Office of
Mined Land Reclamation Active and Inactive Mines