2016-12-01_PERMIT FILE - C1980007A

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 12/1/2016
• Doc Name: delete
• Section_Exhibit Name: Exhibit 71
• Media Type: D
• Archive: Yes

HYDROLOGIC CHARACTERIZATION AND MONITORING PLAN
This document reflects revisions to Mountain Coal Company, LLC's (MCC) hydrologic
characterization and monitoring plan as approved by the Colorado Division of Reclamation,
Mining and Safety (CDRMS) per PR -12 (2007) and TR -139 (2016). A detailed description of the
changes made in 2016 to the approved hydrologic monitoring network is presented in the
Technical Memo entitled, "2016 Recommended Modifications to the West Elk Mine Hydrologic
Monitoring Network (HydroGeo, 2016b) " that can be found in Appendix A.
1.0 SUMMARY
Mountain Coal Company, LLC (MCC) plans to continue development and longwall mining of
fee and federal coal leases located south of the existing West Elk Mine (WEM) site, in the South
of the Divide (SOD) and the Dry Fork Lease (DFL) areas. The boundaries and locations of the
coal lease areas are illustrated on permit Map 34. This Exhibit includes detailed hydrologic
characterizations of the SOD and DFL areas and a site -wide hydrologic monitoring plan. MCC
retained HydroGeo, Inc. (HydroGeo) to prepare Exhibit 71, and provide monitoring and
additional hydrologic consulting services, as necessary, to comply with this approved plan.
HydroGeo is very familiar with the hydrology of the WEM area, as a result of expertise gained
while conducting the annual hydrologic monitoring and preparing Annual Hydrology Reports for
the WEM, as required by the CDRMS, for the past several consecutive years. In addition,
HydroGeo has over 40 years of professional consulting experience, covering a vast array of
mining -related hydrology issues for projects in the U.S. and abroad.
This report characterizes the surface and groundwater hydrology in the SOD and DFL areas
including the Deep Creek, Dry Fork, Lick Creek, and South Prong Creek drainages. It also
summarizes the overall hydrologic monitoring plan for the WEM.
The information presented in this report is derived, in part, from the following resources:
o Annual Hydrology Reports (AHR), West Elk Mine (HydroGeo, 2002 — 2015)
o Baseline water quality statistics, Pre -2000 data (Wright Water Engineers (WWE, 200 1)
o Seep, Spring, and Stock Pond Inventory of the South of Divide Study Area (WWE,
1997b)
o Updated Natural Resources Inventory for South of Divide Study Area (WWE, 2005)
0 2004 aerial photographs of the WEM area (MCC, 2005)
o U.S.G.S. quadrangle maps of the area.
Water quality and flow data for surface water, springs/seeps, and well monitoring sites for WY
2015 are presented in Appendices B, C, and D, respectively. Complete historical surface water
quality and flow data are presented in the Annual Hydrologic Reports (AHR) prepared by
HydroGeo (2002 to 2016a).
2.0 SOD AND DFL AREAS SURFACE WATER HYDROLOGY
The SOD and DFL areas include portions of four drainages: Dry Fork, Lick Creek, Deep Creek,
and South Prong Creek (Plate 1). The main SOD area is drained by Dry Fork and Lick Creek
and the small northeast arm of the SOD and DFL areas is drained by upper Deep Creek. A small
Revised 09/07- PRI 2; 08/16- TRI 39 HydroGeo, Inc.