2010-10-12_REPORT - C1982056

• Permit No: C1982056
• IBM Index Class Name: REPORT
• Doc Date: 10/12/2010
• Doc Name: 3rd Quarter 2010 Refuse Pile ‎(via email)‎
• From: Northwest Colorado Consultants, Inc.
• To: Twentymile Coal Company
• Permit Index Doc Type: Waste Pile/Fill Report
• Email Name: JDM
• Media Type: D
• Archive: No

Geatechnlcal / Environmental .Engineering - Materials Tesdng
October 8, 2010
Twentymile Coal Company
29515 RCR #27
Oak Creek, CO 80467
Attn: Mr. Jerry Nettleton
Job Number: 99-3983
Subject: Quarterly Observation Report, Refuse Pile,
Foidel Creek Mine, Routt County, Colorado.
Mr. Nettleton,
As requested, NWCC, Inc. (NWCC) has prepared this report outlining our observations made during the
third quarter of 2010 at the Refuse Pile, which is located at Twentymile Coal Company's (TCC) Foidel
Creek Mine in Routt County, Colorado. During this quarter, Tim Travis of NWCC visited the project site
on September 29, 2010 to provide the quarterly inspection/observations of the Refuse Pile.
It was noted in our quarterly inspection report for the second quarter of 2010 dated July 30, 2010 that no
compaction tests were taken between April and June of 2010. However, a representative of NWCC visited
the refuse pile on April 12, 2010 to take compaction tests in Areas 2, 3 and 4. A total,of five compaction
tests (#437 to #441) were taken in Areas 2, 3 and 4 during this visit.
In addition, a representative of NWCC visited the refuse pile on July 14, 2010 to take compaction tests in
the Expansion Area of the refuse pile. A total of five compaction tests (#442 to #446) were taken in
Expansion Area near the newly constructed underdrain during this visit. All of the tests taken on these
dates met the minimum compaction requirement of 90% of the maximum standard Proctor density. Copies
of the compaction test results and the daily field reports are attached. It should be noted that the
abbreviations given in the Nuclear Density Test Results (Proctor Data) are as follows: Maximum DD =
Maximum Dry Density and OMC = Optimum Moisture Content. Both of these' values have been
determined in accordance with ASTM D698.
At the time of our site visit on September 29, 2010, we completed a cursory site inspection of the existing
pile. Based on our observations made during this visit, it appeared that the contractor was presently
stockpiling the refuse coal in Areas 2, 3 and 4 of the pile, as well as along the newly constructed underdrain
in the refuse pile expansion area.
The surface drainage conditions generally appeared to be adequate across the top and sides of the existing
pile. However, the shallow erosion channel located on the lower bench on the east side of the refuse pile,
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