2015-02-26_REPORT - C1982056

• Permit No: C1982056
• IBM Index Class Name: Report
• Doc Date: 2/26/2015
• Doc Name: Foidel Subsidence Evaluation Part 1
• From: DRMS
• To: Nicole Caveny
• Type & Sequence: PR10
• Permit Index Doc Type: Subsidence Report
• Email Name: JLE
• Email Name: DIH
• Media Type: D
• Archive: No

SubTerra, Inc. Peabody Twentymile Coal LLC 09/27/2014
Foidel Creek Mine
Permit Revision for Longwall Mining in the Wolf Creek Seam - Subsidence Evaluation
1. INTRODUCTION
This Permit Revision PR13 -10 for Longwall Coal Mining covers Peabody Twentymile Coal, LLC's
(TC's) startup of its longwall mining operations in the Wolf Creek Seam at the Foidel Creek Mine near
Steamboat Springs, Colorado (Drawing 1). Plans call for mining to be completed in nine (9) longwall
panels (Panels 1 -Right through 9- Right) during this phase (see Drawing 2). Current plans also involve
extracting the panels beginning with 7 -Right through 1- Right, then coming back to mine Panels 8-
Right and 9 -Right and retreating each panel from the northeast towards the southwest, in the noted
sequence.
The scope of work covered by this report includes:
1. Prediction of subsidence for initial and subsequent panel extraction.
2. Prepare subsidence spreadsheet used to compute area subsidence and subsidence of
Fish Creek, Foidel Creek, Railroad, Archer- Hayden and Craig- Hayden - Steamboat
3451230 KV Double Circuit and Foidel Creek - Steamboat Transmission Lines.
3. Prepare base map and subsided section for the Power line alignments.
4. Prepare base map and subsided section for the Energy Spur Railroad alignment
5. Prepare base map and subsided map for Fish Creek and Foidel Creek.
6. Prepare evaluation of subsidence impacts on the railroad, power transmission lines, and
creeks.
7. Prepare evaluation of subsidence impacts on wells.
B. Prepare this Permit Report, written as a stand -alone report utilizing background and
historic data from the Foidel Creek Mine.
1.1. Prior Work
Twentymile Coal, LLC and SubTerra, Inc. have previously quantified and monitored impacts of
subsidence on the types of structures and natural features noted above at the Foidel Creek Mine and
have developed a substantial database of published and submitted subsidence data and information
(see Attachment 8).
Subsidence effects on the county roads that cross the Foidel Creek Mine have been evaluated in
several prior reports, including SubTerra, Inc.'s evaluation of impacts associated with rock -fall hazards
from the Twentymile Cliff (SubTerra, Inc., 19961) and predictions for the Western, Northern and
Eastern Mining Districts of Foidel Creek Mine's Wadge seam.
Power line subsidence impacts have been evaluated for lines owned by all three power companies in
the region and the owners of the power transmission lines above the Foidel Creek Mine.
Permit Revision PR03 -06 for the Foidel Creek Mine presented our original analysis of potential
impacts to Fish Creek and its AVF due to subsidence from Panels 12- to 16 -Right in the Wadge
seam's Northern Mining District (SubTerra, Inc., 19992) and Panels 17 and 18 -Right (SubTerra, Inc.,
' SubTerra, Inc., 1996. Evaluation of Potential Rockfall Impacts to County Road 27, Project 96 -26
2 SubTerra, Inc., 1999. Northern Mining District AVF Subsidence Prediction, Project 99 -03.