REV15274

• Permit No: C1981038
• IBM Index Class Name: Revision
• Doc Date: 10/28/1991
• Doc Name: PN C-81-038 TR 91-16 SUBSIDENCE MONITORING REDUCTION
• From: CYPRUS ORCHARD VALLEY
• To: MLRD
• Type & Sequence: TR16
• Media Type: D
• Archive: No

III IIIIIIIIIIIIIIII
999
C c~RUs
'~ Orchard Valley
Cyprus Orchard Valley Mine
P.O. Box 1299
Paonia, CO 81428
Phone: [phone]
Fax: [phone]
October 24, 1991
Mr. Randall P. Price
Reclamation Specialist
Colorado Mined Land Reclamation Division
215 Centennial Building
1313 Sherman Street
Denver, ~ 80203

OCT 2 8 ~gg~
Mined Land
Reclamation Division
RE: PERMIT NO. C-81-038, TEC[-II~ICAL REVISION 91-16, SU6SIDIIJCE MONITORING
REDUCTION
Dear Mr. Price
Cyprus Orchard Valley Coal Corporation (COVCC) is requesting a technical revision
to the above referenced permit. The revision will allow for subsidence monument
surveying to be temporarily discontinued over those inactive portions of the
Orchard Valley mine which were sealed following the mine fire in 1986. More
specifically, the revision will el~m;nate the commitment to annually survey the
high resolution grids located over pillared areas of the now inactive East mine.
Further, the revision will allow COVCC to tenglorarily discontinue annual surveys
of those wide-spaced monitoring monuments which are located over stabilized or
inactive portions of the mine worki ms. Subsidence data has been routinely
collected from these sites aril indicates that the areas have stabilized.
Subsidence data pertaining to these locations is contained in the 1990 Annual
Subsidence Report recently submitted to the Division.
It is the COVCC's understanding that CMLRD regulations, Section 2.05.6(6)((b),
require a deYprm;nation be made with regard to whether or not subsidence, if it
occurred, could cause material damage or diminution of the reasonably foreseeable
use of structures and renewable resource lands within the permit and adjacent
area. If a negative detena;nation is reached, regulations call for a monitoring
program (Section 2.05.6(6)(c)) to be implemented to substantiate the accuracy of
that detP~~nation. If a positive determination is reached, as was the case at
Orchard Valley, regulations call for additional information to be included in the
permit in the form of either a subsidence study (Section 2.05.6(6)(e)), or a
subsidence control plan (Section 2.05.6(6)(f)).
Permit No, C-81-038 contains a subsidence study, a subsidence control plan, and
a subsidence monitoring program (see Volume 3, Subsidence Appendices). The
subsidence monitoring program is called for within the subsidence study to verify
the predictions made therein and consists of a wide-spaced monitoring grid
intended to provide general information on horizontal and vertical displacement