_ENFORCEMENT - C1981017 ‎(9)‎

• Permit No: C1981017
• IBM Index Class Name: Enforcement
• Doc Name: Bid Documents ‎(IMP)‎ CV-91-023
• Violation No.: C-91-023
• Media Type: D
• Archive: No

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Mine 1
Many of the comments pursuant to Mine 4 would also apply to Mine
1 . Additional concerns noted and ideas discussed include the
following:
Portions of the bench are within avalanche zones which
preclude the use of permanent sediment control ditches or
berms . Use of temporary sediment controls such as silt
fencing or straw bale dikes may be appropriate within the
avalanche chutes along the outside edge of the mine bench.
The structures would be removed prior to significant snow
accumulation and replaced after the avalanche season has
passed. Similar measures should be employed at the base of
the downslopes.
A general mine bench maintenance and snow removal plan should
be included as a component of the interim stabilization plan
for the portal bench downshopes.
Large gullies in the revegetation test section area should be
riprapped or otherwise stabilized.
Mine 2
Problems less severe that at Mine 4 and Mine 1 portal bench
downslopes . Barren downslopes should be revegetated .
Mine 3
- The north facing portal bench downslope is largely devoid of
vegetative cover and is not currently controlled by any type
of siltation structure. An old road provides access to the
base of the downslope from the RD-2 switchback on Road F. A
silted-in beaver pond below the base of the downslope should
be considered for sediment pond development . A significant
portion of the downslope drainage is currently skirting
around the pond site, but the drainage could be re-directed
if a sediment pond were to be constructed . The north
perimeter ditch on the mine bench should be maintained to
clean out sediment and eliminate ponding of water.
Mine 5
- Unlike the other portal areas the Mine 5 bench downslope
drainage is routed through a sedimentation pond . One problem
noted was that drainage being diverted from the AML project
site has been directed into the Mine 5 sediment pond
collection system. Measures necessary to safely divert this
drainage around the pond while still routing Mine 5 disturbed
drainage into the pond will need to be taken. The drainage
plan will need to be modified accordingly.