2010-10-19_REVISION - C1982056 ‎(2)‎

• Permit No: C1982056
• IBM Index Class Name: REVISION
• Doc Date: 10/19/2010
• Doc Name: Letter, Application & Public Notice ‎(emaiedl)‎
• From: Twentymile Coal, LLC
• To: DRMS
• Type & Sequence: TR76
• Email Name: JDM
• Media Type: D
• Archive: No

Peabody
Twentymile Coal Company
Mr. Jason Musick
Environmental Protection Specialist
Colorado Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, Colorado 80203
[phone] X8134
29515 Routt County Road #27
Oak Creek, CO 80467
970.879.3800
October 13, 2010
RE: Twentymile Coal, LLC - Foidel Creek Mine (Permit No. C-82-056), Technical Revision
(TRO10-76) for Ditch G6 Extension
Dear Mr. Musick:
Twentymile Coal, LLC (TC) requests CDRMS approval of a Technical Revision (TRIO-76) to the
approved Permit, for installation, operation, maintenance, and reclamation of an extension of the existing
discharge ditch for Pond G, to route discharge flows around an existing wet area to the existing road
culvert under Routt County Road 27 (RCR27). Presently, the pond discharge spreads-out into a low area
on the south side of the existing UPRR rail-spur, which naturally drains to the existing road culvert. With
installation of the 6RT Thickener Underflow Borehole and Pipeline (TR09-69), it is desirable to drain the
low-lying wet area to facilitate pipeline installation, ongoing inspection and monitoring, and any
necessary future maintenance activities. The proposed ditch extension will be a 450 foot long trapezoidal
ditch approximately 1.5 feet deep, with an 8 foot top width. The ditch bottom will be over-excavated and
re-compacted, in order to minimize infiltration. The location and configuration of the proposed Ditch G-6
Extension is shown on Map 24, Surface Facilities and Freshwater Systems. SEDCAD+ design
calculations are provided in Exhibit 8J, CYCC Pond G - Stage Storage.
Installation of the proposed Ditch G-6 Extension will involve the following:
? Placement of straw wattles downgradient of the ditch construction area
? Removal and temporary windrowing of soil material and vegetation on the upgradient side of the
ditch construction area
? Construction of the ditch, including over-excavation and re-compaction of the ditch bottom
? Replacement of soil material and vegetation on the ditch area
? Connection of the ditch ends to the existing ditch and road culvert
TC plans to initiate ditch construction immediately on receipt of the required permit approval, and
anticipates that ditch construction can be completed in a relatively short timeframe (7-10 days). Given
that there is little or no discharge from Pond G at this time of year, and the current drainage configuration,
any minor discharge from Pond G during construction will continue to be routed through the low-lying
area to the existing road culvert. In addition, given the short duration of construction, recovery and
replacement of soil and vegetation should result in effective revegetation of the ditch construction area.
If, following the first growing season after completion of construction, revegetation is not adequate, TC
will complete supplemental reseeding, as necessary.
C:\Documents and Settings\ahd\Local Settings\Temporary Internet Files\Content.Outlook\3Q03WBR1\TR10-76 Ditch G-6
Extension TL.doc