_GENERAL DOCUMENTS - C1981017 ‎(149)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

CO
H� 90 DEPARTMENT OF NATURAL RESOURCES
* * David H.Getches,Executive Director
MINED LAND RECLAMATION DIVISION
1876 DAVIDC. SHELTON, Director
Richard D.Lamm ,
Governor
M E M O R A N D U M
3 ecember 1984
TO: Jim Heron
FROM: Jim Pendleton —
RE: Coal Basin Mi. 19 4 Subsidence Monitoring Reports
Pursuant to your requ I have reviewed the two subsidence monitoring
reports submit Mid-Continent Resources, Inc. for the Coal Basin Mines.
These two reports are dated July 23, 1984 (Received August 8, 1984) and
November 2, 1984 (Received November 19, 1984) .
The July 23, 1984 subsidence monitoring report presents the subsidence
monument survey data for monuments MC-2 through MC-6, MC-8 and MC-9. As of
the July 3, 1984, when the survey was performed, monument MC-5 had displayed
cumulative vertical subsidence of -1 .73 feet, the maximum observed since the
initiation of monitoring in August of 1981 . The survey and report are
acceptable, however, the operator' s attention is directed to the comment here
below regarding future report' s content.
The November 2, 1984 subsidence monitoring report presents the subsidence
monument survey baseline data for newly installed monuments MC-10 through
MC-16 and newly installed survey control point TP-6. The report also reports
a resurvey of the original survey control points TP-1 through TP-5. As a
result of this survey control points TP-1 and TP-5 were found to have been
subsided. Survey control points TP-2, TP-3 and TP-4 continue to be reliable,
existing outside areas of subsidence impact. As of the September 17 through
September 20, 1984 survey, monument MC-4 displayed cumulative vertical
subsidence of -2.12 feet, the maximum observed since the initiation of
monitoring in August of 1981 .
The contents of the November 2, 1984 report, as well as the survey techniques
utilized, are acceptable. However, the Division directs the operator to make
one addition to the text discussion of future subsidence reports. The purpose
of subsidence monitoring reports, as stated in the findings for the Coal Basin
permanent program permit, is to verify the technical subsidence projections
contained within the permit application. For this purpose, the operator is
directed to include a comparative discussion of the permit application
subsidence projections and the observed subsidence. The operator' s report
should clearly discuss whether or not the observed subsidence verifies the
predictions contained within the permit application. If they do not, the
applicant should resolve the disparity and amend the permit application or
mine plan appropriately.
cc: Brian Munson
Doc. No: 5741F
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]