REP34870

• Permit No: C1981044
• IBM Index Class Name: Report
• Doc Date: 3/1/1993
• Doc Name: SUBSIDENCE REPORT REVIEW FROM JUN 1991 - DEC 1992 EAGLE 6 MINE C-81-044
• From: DMG
• To: STEVE WATHEN & FILE
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
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1313 Sherman St., Room 215
Denver, CO 80203
Phone: [phone]
FAX: [phone]
March 1, 1993
TO: Steve Wathea F' e
FM: Shawn Smith C/
Re: eubsidence ort Review from June 1991-December 1992
Eagle No.6 Miae (C-81-044)
Dear Steve:
Roy Romer
Governor
Michael B Long
Division Dneclrn
I have reviewed three subsidence reports; June-Dec 1991, January-
June 1992 and July-December 1992. All reports are for the Eagle
No.6 Mine with the "E" seam workings. The mine has previously
mined the "F" seam, above the current "E" seam. Historically the
"F" seam has been mined in the following manner: room and pillar
to the west (old workings- pre-1980) and long wall operations to
the east.
I. Background
The following review is based on each monument series, "A","B",
"C", "D" and "S". Monument series A,B,C and D are overlying both
room and pillar workings on the "F" seam which are also undermined
by the long wall panel operations for the "E" seam. The "S" series
is overlying a long wall operation for the "F" seam and the "E"
seam. The third case is single long wall operation for the "E"
seam. These three cases each have a separate calculation for
maximum subsidence; referred to as Smax. These are:
Case 1: Two underlying long wall panels Smax predicted= 13.0'
Case 2: One long wall panel under room and pillar = 10.5'
Case 3: Single long wall panel
= 7.5'
In all three cases these are predicted amounts of maximum
subsidence. The case does not exist where there are both room and
pillar workings and long wall mining excavations of the "F" seam
above the current long wall "E" seam operations. Either there are
just room and pillar workings above the current long wall
operation, or. there are undermined long wall panels above the
current long wall operations.
The extraction height in all three reports was 10 feet.
Each monument series comments are indicated below.