ENFORCE20007

• Permit No: C1981038
• IBM Index Class Name: Enforcement
• Doc Date: 5/17/1993
• Doc Name: PN C-81-038 NOV C-93-030 OVWM PORTAL CUT SLIDE REPAIR
• From: CYPRUS ORCHARD VALLEY
• To: DMG
• Violation No.: CV1993030
• Media Type: D
• Archive: No

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999
C c~RUs
~ Orchard Valley
Cyprus Orchard Valley Mine
P.O. Box 1299
Paonia, CO 81428
Phone: [phone]
Faz: 303-527-2234
May 12, 1993
RECEIVED
Mr. Steve S. Shuey MAY 1 7 1993
Reclamation Specialist
Division of Minerals and Geology Division of Minerals ~ Geology
1313 Sherman Street, Room 215
Denver, ~ 80203
RE: PERMIT NO. C-81-038, NOV C-93-030; OVWM PORTAL CUP SLIDE REPAIR
Dear Mr. Shuey:
In March of 1993, a slide developed at the Orchard Valley West Mine portal cut.
NOV C-93-030 was issued by the Division as a result. NOV C-93-030 abatement step
number one (1) directed Cyprus Orchard Valley Coal Corporation (COVCC) to submit
to the Division by May 12, 1993, a report addressing: the causes of the slide;
a plan to repair the cut failure; and a plan to prevent future slide occurrence
on the cut face. This submittal is intended to meet the requirements detailed
in abatement step number one (1).
Lambert & Associates, a geotechnical engineering firm, was retained to evaluate
the slide area and provide insight as to the causes and potential remediation
steps appropriate to stabilize the area. The report generated by Lambert is
included with this submittal.
While it is difficult to pinpoint the enact causes of the slope failure,
unusually high soil moisture content is believed to be the overriding factor.
High soil moisture levels resulted from a combination of above average
precipitation and unusually mild winter temperatures which failed to produce a
hard and persistent freeze in the soils of the area.
There are basically three avenues for soil moisture to have been contributed to
the slope: surface runoff; subsurface flow; or direct precipitation. After
observing the failed slope and surrounding areas, COVCC believes that direct
precipitation contributions on the exposed face of the OVWM portal cut were
primarily responsible for moisture acciumilations in the material which resulted
in slope failure. SYil~surface flow contributions are discounted primarily due to
the location of the slope failure within the portal cut area. Surface runoff
contributions likely played amore significant role but are also discounted
relative to direct precipitation contributions given the steep slope of the
portal cut face.
The slope failure occurred along the southern edge of the portal cut where