2015-07-10_REPORT - C1982056

• Permit No: C1982056
• IBM Index Class Name: Report
• Doc Date: 7/10/2015
• Doc Name: 2nd Quarter 2015 Refuse Pile Report
• From: Twentymile Coal Company
• To: DRMS
• Permit Index Doc Type: Waste Pile/Fill Report
• Email Name: JLE
• Email Name: DIH
• Media Type: D
• Archive: No

INortiiwest Colorado Consultants, Inc.
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Q Geotechnical! Environmental Engineering - Materials Testing
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July 9, 2015
Twentymile Coal Company
295 t5 RCR 927
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
second quarter of 2015 at the Refiise Pile located at Twentymile Coal Company's (TCC) Foidel Creek Mnic
in Routt County, Colorado. During this quarter, Timothy Travis of NWCC visited the project site on June
30, 2015 to provide the quarterly inspection/observations of the Refuse Pile.
At the time of our site visit on June 30, 2015, NWCC completed a cursory site inspection of the existing
refuse pike. Based on our observations made during this visit, it appeared that the contractor was presently
stockpiling and compacting the refuse coal hi the new Expansion Area. At the time of our site visit the
refuse coal had been placed and compacted to an elevation near the second bench along the east side of the
stockpile.
In addition, a representative of NWCC visited the refuse pile on June 23, 2015 to conduct compaction
testing in the new Expansion Area of the refuse pile. A total of four compaction tests (#526 to 4529) were
taken in Expansion Area during this quarter. All of the tests taken during this quarter rnet 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.
The internal roadways in the new expansion area of the pile were in good condition. The upper haul road to
Areas 2, 3 and 4 of the refuse pile was not accessible at the time of our site visit. Tile surface drainage
conditions generally appeared to be adequate across the top and sides of the pile. It did appear that re-
grading of the drainage port area previously observed hi Areas 2, 3 and 4 had been completed. The top of
Areas 2, 3 and 4 was not accessible at the time of our visit to observe the drainage conditions above the
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