_INSPECTION - C1994082 ‎(77)‎

• Permit No: C1994082
• IBM Index Class Name: INSPECTION
• Doc Name: Inspection Report
• Inspection Date: 6/16/2009
• Email Name: DTM
• Media Type: D
• Archive: No

III. COMMENTS - COMPLIANCE
Below are comments on the inspection. The comments include discussion of observations made
during the inspection. Comments also describe any enforcement actions taken during the inspection
and the facts or evidence supporting the enforcement action.
Backfill and Grading; Slides and Damage
Hillslope Stability and Erosion
Slump and settling features ranging from significant landslides to minor settling cracks have developed on
reclaimed spoil and graded slopes at Yoast. The most severe slide is on the slope immediately to the northeast
of Pond 12 ("the Pond 12 slide"), which has been extensively documented in inspection reports over the last two
years. Geotechnical evaluation and monitoring is continuing on the Pond 12 slide, and a remedial plan is to be
submitted later this year.
A much smaller slope failure, but still a significant slump, occurred this spring on a steep slope in the upper
Pond 13 watershed, due east of Pond 13. Slope gradient in the slump vicinity is approximately 35-40%. The
feature exhibits a semi-circular scarp averaging approximately 3 to 4 feet in height; distance across the slump
along the contour of the slope from north to south is approximately 120 feet. The block of ground that moved,
evidenced by numerous cracks and bulges, extends down slope from the upper scarp for approximately 70'.
The slump will need to be repaired this year. Repair may need to include elimination of a temporary
road segment that passes along the slope just above the scarp, and grading of the slope crest to a
lesser gradient(which would necessarily extend the boundary of the disturbed area further to the east).
The remedial plan for this slump feature should be submitted within a supplement to the 2009 Rill and
Gully plan, or within a technical revision application (a TR will be required if the plan involves extension
of the disturbed area boundary, as would appear to be warranted).
Remaining features indicative of settling or minor slope movement include minor cracks and slumps along or in
the immediate vicinity of the north end of the SP07-1 fenced shrub area, and a short crack/scarp located
immediately south of Pond 12(noted in previous inspection report). Previously repaired cracks in several
locations on the reclaimed highwall slopes along the northern perimeter of the North Pit area, and a few other
locations were marked on the 2009 Rill and Gully Map. From a distance, it was not apparent that the cracks
had re-opened, but these features and certain others marked on the map were not closely checked, and will
need to be ground checked by the operator. Remedial grading of these minor cracks and slumps will need
to be completed this year as warranted, in accordance with the rill and gully plan.
Hillslope rills and gullies that warrant repair this field season in accordance with the approved rill and
gully plan were observed in several locations, including the following:
• Minor gullying on slope southeast of large fenced shrub area SP06-1,just to the east of the upper end
of riprap on Channel YPM 1-1.
• Gully from near northeast corner of fenced shrub area SP05-1 down to YPM 3-2.
• Gully on south facing slope from ridge near"elk wallow"down to YPM 3-2, between fenced shrub areas
SP05-1 and SP06-3.
• Gully along north side of shrub area SP05-1.
• Short gully just west of shrub area SP06-3 that feeds into YPM 3-2.
• Short gully at southeast inlet to Pond 14.
• Gully that extends from the large unfenced roughened soil shrub area (2002 Upland Shrub)down to a
point approximately 30 yards northeast of the upper end of Channel YPM 21-13. Low impact hand-work
repairs such as small rock or wattle checks in series may be sufficient to facilitate healing while
minimizing disturbance to established vegetation.
• In the first 200 yards or so downstream of Stock Pond ST-1, along YPM-1-2, there are a couple minor
gullies along the vegetated slope east of the channel that extend to or almost to the channel. Hand
work repairs may be warranted.
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