INSPEC09399

• Permit No: C1981012
• IBM Index Class Name: Inspection
• Doc Date: 7/8/1997
• Doc Name: OSM INSPECTION REPORT
• Inspection Date: 6/10/1997
• Media Type: D
• Archive: No

amples but that high moisture content reduced compaction, reinforcing the need to
ensure positive drainage off the piles.
According to OSM's records, the requirement at section 4.09.1(11)(c) that color
photographs be inGuded with any certified report addressing underdrain systems and
protective filters was proposed in its entirety on September 9, 1988, and was approved
by OSM effective December 11, 1989. Underdrain construction completed prior to that
approval date would not have to be recorded on color photographs submitted with
engineer's reports. I reviewed photographs of underdrain construction, inGuding use of
Mirafi filter fabric, taken during initial construction (prior to 1989) and construction of
drain extensions built in November 1990 and May 1993. DMG also had at its Denver
office photographs of the underdrain taken during inspections in 1993. My review of the
engineer's reports showed that color photographs were not referenced in the operator's
submittals. Nevertheless, the operator had color photos of underdrain construction and
engineer's reports at the mine office.
2. Mine Waste Development Pile
The MWDP is located south of highway 12 and west of the mine entrance road. Its
MSHA identification number is 1211-CO-00296-01. DMG permitted it in 1981, though its
initial construction pre-dates SMCRA. In accordance with section 4.09.1(13), the
MWDP does not have an underdrain because it is not located in a drainage or in an
area with springs or seeps. With the exception of maintenance, it has been inactive
since the end of the first quarter of 1996. Approved design parameters for the MWDP
include: 2h:1v maximum slope steepness (s 50%, or 26° 34'); lifts constructed in layers
2 feet thiGc or less compacted to 90%; and maximum lift thickness of 50 feet. Three
ditches controlling runoff from the MWDP were designed with trapezoidal cross-sections
to handle runoff from 100-year, 24-hour precipitation events. A minimum of four feet of
non-toxic material must be placed on top of the coal waste following final grading prior
to final revegetation according to section 4.10.4(5).
The site on which the MWDP was constructed slopes southward toward the Purgatoire
River. Drainage from the MWDP is routed through three ditches into ponds 004 and
007. Drainage from the first lift of the MWDP is handled by ditch D4 on the pile's south
side and is routed to pond 007 east of the mine access road. Runoff from the second
lift enters ditch D2 on the south side of the pile then encircles the pile's south, east, and
north sides before draining to pond 004 west of the pile. Ditch D3 captures water from
the west side of the pile and also drains into pond 004.
Coal waste material below ditch D4 on the MWDP's south side forms an embankment
along the river. That part of the embankment below the western-most 200 feet or so of
the MWDP is steep and eroded in places; one measurement showed an approximate
slope of 37°. DMG noted that the material comprising this embankment is part of the
MWDP's original footprint, which was constructed prior to SMCRA under MSHA
approval.
3 1997 New Elk Special Focus