REP47385

• Permit No: C1981013
• IBM Index Class Name: Report
• Doc Date: 9/5/1996
• Doc Name: 1ST HALF 1996 SUBSIDENCE REORT GOLDEN EAGLE MINE C-81-013
• From: DMG
• To: DAN HERNANDEZ
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources
1313 Sherman SI., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
Date: September 5, 1996
m~~ nar, Hernandez
From: Kent
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DEPARTMEIJT OF
NATURAL
RESOURCES
Roy Romer
Governor
lames 5. Lochhead
E><ecmive Director
Michael 0. Long
Division Director
RE: 1st Half 1996 Subsidence Report, Golden Eagle Xine, fC-81-013
I have completed review of the 1st Half 1996 Subsidence Report for the Golden Eagle mine
and forwarded my comments resulting from that review to the operator. You were copied
on that separate correspondence.
Basin completed the required monitoring as per the approved plan. Monuments were
surveyed quarterly as required on 5 sets of monuments. All monuments showed minimal
further subsidence movement, mainly because longwall mining ceased in late December of
1995.
The worst possible consequences of subsidence with regard to each structure or renewable
resource land are listed in the permit. They include the Rancho Escondido water line,
aquifers and wells, roads and culverts, power lines and telephone lines, pump stations and
stock pond, and structures (likely meaning buildings, which there are apparently none in the
affected area).
The subsidence monitoring plan, as it is currently approved, is not designed to confirm or
disprove Basin's predictions of worst possible consequences. However, it is designed to
monitor and measure subsidence which occurs as a result of longwall mining to allow
comparison to predicted ground movement. In that respect, Basin's subsidence monitoring
data indicates that their prediction of maximum subsidence of 4.5-6.5 feet is reasonably
accurate over the center of the panels. Data collected from the NW3 series of monuments
confirms an angle of draw of 15.6 degrees at S00 feet of overburden, and 11.3 degrees at 700
feet of overburden. This is within the prediction provided by the operator.
Given the data collected, the results of field inspections, and predictions in the currently
approved permit application, the operator is conducting activities within the constraints of
the permit and the Rules governing coal mining.
If you have additional questions, let me know.