2012-11-15_REVISION - C1996083 ‎(5)‎

• Permit No: C1996083
• IBM Index Class Name: REVISION
• Doc Date: 11/15/2012
• Doc Name: Proposed Revised Pages
• Type & Sequence: TR76
• Email Name: SLB
• Media Type: D
• Archive: No

evaluates the maximum height of the Gob pile at 150' instead of the original pile
height of 118 feet.
Buckhorn Geotech evaluated the as -built configuration of gob pile #4. It was
prepared September 5, 2012. The analysis is based on actual construction of
the pile, and utilizes soil parameters as discussed in the original report dated
February 1, 2007. The as -built configuration has been determined to be stable.
Buckhorn Geotech prepared a stability analysis evaluating the Gob Pile #2
expansion. It was prepared November 9, 2012. The report concludes the pile
will be stable with slopes no steeper than 3h:1 v with 15' wide terraces on 50 to
60' intervals with the first 50' sloped no steeper than 2.5h:1 v.
The Operator commits to having a qualified third party geotechnical firm perform
monitoring and testing. Monitoring will consist of observations of the
geotechnical aspects of the construction to determine if any unusual or
unexpected conditions are encountered. Testing will include compaction tests
and periodic strength tests. Results of the tests and any observed unusual or
unexpected conditions will be submitted to the DRMS with the quarterly
inspection reports.
The quarterly reports will also include a summary of instrumentation monitoring
on coal mine waste pile number 2. This report will include a discussion of the
inclinometer data and the vibrating wire piezometer data. The inclinometer data
will determine if there are indications of deep- seated instability. The vibrating
wire piezometer data will determine if the measured pore pressures are relatively
stable and consistent with the September 22, 2008 stability analysis performed
by Buckhorn Geotech, Inc.
The Operator commits to having a geotechnical engineering firm continue
instrumentation monitoring, at a minimum, once per quarter. Additional
inclinometers and vibrating wire piezometers may be installed at the discretion of
the geotechnical engineering firm.
In addition to the five piezometers (only three are still in working order) installed
in June of 2005, three additional piezometers were installed during the week of
TR -76 - 17 - 11/12