_INSPECTION - C1982057 ‎(73)‎

• Permit No: C1982057
• IBM Index Class Name: INSPECTION
• Doc Name: Inspection Report
• Inspection Date: 7/28/2010
• Email Name: DTM
• Email Name: SB1
• Media Type: D
• Archive: No

July 28, 2010 C-1982-057/Seneca II-W Mine DTM
of the entire length of Channel PM-4D,the installation functioned well,and vegetation is beginning to take root
and grow up through the TRM. Near the extreme lower end of the channel, it appears that snowmelt runoff may
have escaped out the channel and under-cut TRM liner adjacent to the channel. Maintenance will be necessary in
this location,and has been marked on the R&G Map. Extent of cover provided by seeded vegetation stands on the
upland slopes in the ridgeline watershed appears appreciably approved compared to previous years, which should
enhance the potential for long term erosional stability of PM-4D.
Drainages in the Pond 017 watershed were also inspected on 7/29. There are several hillslope rills up to 12"deep
in the general area between the fenced shrub plot along lower Channel PM-1, and Stock Pond T-25. Stabilization
measures are warranted. Two surge structures were constructed in the watershed in 2009, one at the junction of
PM-lA and PM-113, and a second further up PM-lA. Both structures appear stable and functional. Minor side
scour evident on Channel PM-1 below the lower structure will require maintenance. Also,the lower section of a
V ditch that feeds into the upper surge structure from the south has incised and will need to be stabilized.Upper
segments of Channel PM-1B will require maintenance to repair areas of side scour and undercutting(the entire
length of this channel should be checked by SCC and repaired as warranted). In general,upper portions of the 017
watershed appear to be stabilizing as seeded vegetation matures and the extent of ground cover increases. The
surge structures and associated cross ditches appear to have functioned well and have resulted in improved
erosional stability of the hillslopes as well as the permanent channels. Areas of minor rilling and settling
(including previously repaired settlement scarps and cracks)appear to be healing over.
On 7/30,1 hiked across the upper portion of several drainages in the 016 watershed,below the Ridgeline Light Use
Road LU5,between the large undisturbed aspen forest block and Stock Pond T-26. Permanent channel segments
observed included portions of PM-2C and its north fork,upper PM-2B, and PM-2D above and below Stock Pond
T-26. I also walked the segment of the light use road between Pond T-26 and the undisturbed aspen forest block,
and slowly drove along the remainder of the light use road through the upper 016 watershed. I took a slope
measurement with inclinometer from a point along the road down to the fenceline a short distance west of the
aspen block(using a fence post for reference height). This location appeared to be one of the steepest slope
segments in the 016 watershed; measured slope was 35%along a 150 foot slope segment. In general, cover of
seeded vegetation in the 016 watersheds is increasing and slopes are beginning to stabilize. Several hillslope
gullies were noted, which warrant stabilization. A gully was observed that enters the north branch of PM-2C from
the east, at its upper end,and a couple gullies were observed on hillslopes either side of PM-2C. An incised
erosion control"wing ditch"that feeds into the lower section of PM-2C was also observed. Sidecutting and
undercutting of TRM liner was noted along 2C, in locations where hillslope gullies entered the channel, and also
along the lower-most segment of the channel. One hillslope gully enters the segment of PM-2D a short distance
up from the surge structure at the confluence of 2D and 2C, and riprap has been dislodged and sidecut along the
same segment of lower PM-2D. Two closely spaced gullies were noted on the slope immediately south of the
light use road, a short distance to the northeast of the fenced shrub plot near Pond T-26. Approximately 500'
northwest of Culvert PM-8 on LU5,the road makes a sharp curve from NW to SW. At this point, concentrated
flow from the road segment to the southwest has resulted in a gully on the reclaimed slope north of the road,which
will need to be stabilized. A number of the erosional features observed in the upper 016 watersheds had not been
noted on the 2010 R&G Map. These features were discussed with the operator following the inspection and were
marked on the operator's"working copy"of the map. It may be the case that other erosional features are present
Number of Partial Inspection this Fiscal Year: 0
Number of Complete Inspections this Fiscal Year: 1
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