2014-08-19_PERMIT FILE - C1980007 ‎(12)‎

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 8/19/2014
• Doc Name: Refuse Pile Expansion East
• Section_Exhibit Name: Exhibit 82 Refuse Pile Expansion East
• Media Type: D
• Archive: No

Refuse Pile Expansion East
Waste Rock Pile
Mountain Coal Company, LLC
West Elk Mine
May 2014 JR 133)
Table of Contents
Certification.................................................................................................................................................
vi
1.0 Introduction............................................................................................................................................1
2.0 Geotechnical Investigation and Design.................................................................................................. 3
2.1 Geotechnical Investigations........................................................................................................ 3
2.1.1 Initial Design Phase Investigation.................................................................................. 3
2.1.2 Construction Phase Investigations................................................................................. 4
2.2 Geotechnical Analysis and Design............................................................................................. 5
2.2.1 Software......................................................................................................................... 5
2.2.2 Model Parameters.......................................................................................................... 6
2.2.2.1 Waste Rock (Refuse)....................................................................................... 6
2.2.2.2 Colluvium........................................................................................................8
2.2.3 Modeling Methodology................................................................................................. 8
2.2.4 Fall 2013 Drilling and Laboratory Testing..................................................................10
2.2.5 Verification of Colluvium Properties...........................................................................
11
2.3 Assessment of Stability.............................................................................................................
11
2.3.1 Assessment of Stability — Design Slope......................................................................
11
2.3.2 Assessment of Stability — Permit Envelope Slope .......................................................
12
2.4 Geotechnical Design.................................................................................................................13
2.5 Subsidence................................................................................................................................13
3.0 Hydrologic Analysis and Design..........................................................................................................14
3.1 Hydrologic Water Balance Analysis.........................................................................................14
3.1.1 Hydrologic Inputs........................................................................................................14
3.1.2 Model Parameters........................................................................................................
15
3.1.3 Model Results..............................................................................................................16
3.2 Hydrologic and Hydraulic Modeling........................................................................................17
3.2.1 Hydrologic Inputs........................................................................................................
17
i
P:\Mpls\06 CO\26\06261003 MCC Refuse Pile Site Review & Permit\WorkFilesTermit Application\2014 Revision\Exhibit 82 2014-05-29.docx