INSPEC41598

• Permit No: C1980005
• IBM Index Class Name: Inspection
• Doc Name: Inspection Report
• Inspection Date: 8/7/2006
• Media Type: D
• Archive: No

III. COMMENTS -COMPLIANCE
~`~ e 7
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.
diversion draining a watershed greater than one squaze mile an as-built certification is required
for this channel. Channel PM-1 as-built certification is pending approval of TR-37; however, the
certified as-built was reviewed by DRMS prior to this inspection and is deemed adequate for the
purpose of this inspection. The design changes to PM-1 were implemented prior to August 2005
(see inspection reported issued 08/26/05). All other permanent channels are designed to safely
convey the peak dischazge from the 10-year, 24-hour storm event in accordance with 4.05.3 and
do not require as-built certifications.
The entire tributary drainage system within the reclaimed azeas has been reconstructed and is
functioning, with exception of Channels PM-8, PM-8A, and PM-8B in the East Wadge Pit area
discussed previously in this report. All pernanent drainage channels were inspected for function
with regard to knickpoints, blending at disturbance boundaries and channel erosion. Channel
gradients were measured at major drainages to evaluate compliance with design criteria. Channel
slopes measured with an inclinometer were all fairly consistent with design slope infonnation.
Only two channel segments had measured slopes substantially greater than the design
information. A representative slope of 29% was measured in the upper portion of PM-8, the
design for this channel indicates that the slope in the upper portion ranges from 15-22%, and a
representative slope of 40% was measured in the steep mid-portion of PM-4; the design for PM-4
indicates slopes range from 31-33%. This is not deemed significant since these were short
segments of the overall channels and the instrument used is designed to provide a field check
only. It was determined that all channels met the minimum design criteria, and many of the
channels were overbuilt with regard to size (bottom width and side slopes), and riprap
requirements. There aze 23 permanent post mine drainage channels as shown on Exhibit 13-2A,
all of these (except PM-8, PM-8a, PM-8b) were determined to be stable and functioning
properly. Examples of some of the well constructed riprap channels and stable v-shape vegetated
channels in various locations of the mine site aze given in Photographs Numbers 14 through 17.
Several post-mine drainage channels as described below will require maintenance to repair
erosion or place additional armoring. These locations identified along post-mine drainages are
not deemed significant enough to exclude the azeas from release of Phase I bond liability;
however, SCC should repair the erosion to ensure long-term stability of the channels. SCC
should use hand maintenance for the erosion azeas to the extent possible to avoid unnecessary
equipment impacts to reclaimed azeas.
The upper PM-6 channel above Stock Pond T-32 should be evaluated for hand repair and
placement of additional riprap. There is minor erosion occurring in the channel above the stock
pond and a short section of the channel is lacking riprap. There is also minor rill and gully
development on the east side of PM-6 below Road F. A short section of the vegetated portion of