REP33909

• Permit No: C1981038
• IBM Index Class Name: Report
• Doc Date: 7/18/1994
• Doc Name: SUBSIDENCE MONITORING
• From: CYPRUS ORCHARD VALLEY
• To: DMG
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

III IIIIIIIIIIIIIIII
999
C c~~us
~ Orchard Valley
Cyprus Orchard Valley Mine
P.O. Box 1299
Paonia, CO 81428
Phone: [phone]
Fax: [phone]
July 14, 1994
Mr. Kent Gorham
EhVironmental Protection Specialist
Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, Colorado 80203
~EGEi VEC
JUG 1 g ~~
Division Of Atmerals ~ ~ec:ogY
RE: SUB.SIDIIdC.'E II~G
Dear Mr. Gorham:
In response to your concerns relative to the permitted subsidence monitoring
program in effect at Orchard Valley, as raised in the adequacy review of
technical revision 25 addressing reduced hydrology monitoring, COVCC respectfully
provides the following information in order to clarify the current status of the
subsidence monitoring program and ~VCC's position with regard to your
modification request. ~VCC understands your general concern to be that while
the current subsidence monitoring conducted is consistent with the terms and
requirements of the permit, the terms and requirements of the permit may not be
consistent with the specific requirements of the regulations. Ct7VCC maintains
that compliance with the regulations has been and continues to be achieved.
At issue is the question of whether or not subsidence monitoring in accordance
with Rule 2.05.6(6)(c) is required for particular features within the COVCC
affected area. The answer to this question begins with the required description
(Rule 2.05.6(6)(b)) of worst possible subsidence consequences for structures and
renewable resource lands identified within the permit area. The required
description under the regulations is specified to include a singular
determination (Rule 2.05.6(6)(b)(i)) of whether subsidence could cause material
damage or diminution of reasonably foreseeable use for structures and renewable
resource lands within and adjacent to the permit area. In Orchard Valley's case,
the required determination (see Volume 1, page 2.05-144) was made in the
affirmative as the potential for significant dewatering of surficial aquifers
within identified renewable resource lands was found to exist (see Volume 1, page
2.05-143).
Some confusion arises in the COVCC permit application document due to the fact
that permit text indicates no material subsidence damage or diminution of the
reasonably foreseeable use of structures is anticipated (see Volume 1, page 2.05-
143). This text is believed to contribute to the Division's perception that the
permit doc~ntpnt contains contradictory language as to whether or not material
damage is predicted. COVCC maintains that this language is not contradictory to
the determination that aquifers within renewable resource lands are at risk under
a worst case subsidence scenario. The regulations require that a singular
determination be made. Given that renewable resource larx9s aquifers could
potentially be materially damaged, an affirmative determination is required