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Navajo Mine 2015

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2015 CHIA for Navajo Mine and Pinabete Permit Areas

As the regulatory authority for the Navajo Transitional Energy Company (NTEC), a Navajo Nation owned Limited Liability Company (LLC), the Office of Surface Mining Reclamation and Enforcement (OSMRE) is required by 30 Code of Federal Regulations (CFR) § 780.21(g) to complete a cumulative hydrologic impact assessment (CHIA). The CHIA assesses whether the mining operation has been designed to prevent material damage to the hydrologic balance outside the permit area. Federal regulation 30 CFR § 780.21(g) states “an application for permit revision shall be reviewed by the regulatory authority to determine whether a new or updated CHIA shall be required.”

Several administrative activities have prompted the need for a CHIA update. On March 30, 2012, OSMRE received a Permit Application Package (PAP) to develop an approximately 5,600 acre new permit area (Pinabete Permit NM-0042A) to continue surface coal mining and reclamation operations post July 6, 2016 at the Navajo Mine. On May 3, 2013, OSMRE received and application from BNCC, to transfer Federal Permit NM0003F to NTEC. Additionally, OSMRE approved an electron Permit Application Package (PAP) on June 30, 2014 for Navajo Mine and Pinabete Permit Areas.

An initial CHIA was prepared in 1984, and amended in 1989. The CHIA was significantly updated in 2012 to identify material damage thresholds and limits. This 2015 CHIA update in administrative in that it:

  • Changes the permittee of Federal Permit NM0003F from BNCC to NTEC in text and PAP references,
  • Clarifies the assessment of two active permit areas (Navajo Mine Permit NM-0003F and The Proposed Pinabete Permit NM-0042A) within the Navajo Tribal Coal Lease, which was completed during the 2012 CHIA update in anticipation of the Pinabete PAP,
  • Updates illustrations, tables, and text to reflect the Navajo Mine and Pinabete Permit Areas,
  • Updates ongoing revisions to the hydrologic monitoring program described at Section 5.2 and Appendix H of this document, and
  • Updates references to locations in the electronic permit application packaged approved on June 30, 2014.
Title Size Type
2015 Navajo Mine and Pinabete CHIA (Entire Document) (76.7 MB)
Table of Contents (3.3 MB)
Chapter 1 - Introduction (7.68 MB)
Chapter 2 - Delineation of Cumulative Impact Area (10.3 MB)
Chapter 3 - Water Resources Uses and Designations (6.96 MB)
Chapter 4 - Baseline Hydrologic Conditions (19.5 MB)
Chapter 5 - Hydrologic Impact Assessment (23.6 MB)
Chapter 6 - Material Damage (2.84 MB)
Chapter 7 - Works Cited (2.88 MB)
Appendix A - San Juan USGS Data (14.9 MB)
Appendix B - Water Uses (36.8 MB)
Appendix C - Navajo Mine Impoundments (85 KB)
Appendix D - Surface Water Data Summary (4.88 MB)
Appendix E - SEDCAD Modeling Reports (8.72 MB)
Appendix F - Groundwater Data Summary (3.43 MB)
Appendix G - Coal Combustion Byproducts Assessment (438 KB)
Appendix H - Hydrologic Monitoring Program Update Tech Memo (4.96 MB)

Page Last Modified/Reviewed: 6/22/20

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