Execution Version

LETTER AGREEMENT TERMINATION

July 1, 2015

    
Reference is made to that certain Letter Agreement, dated May 14, 2015 (the
“Letter Agreement”), by and between Public Service Company of New Mexico, a New
Mexico corporation (“PNM”) and Westmoreland Coal Company, a Delaware corporation
(“Purchaser”), pursuant to which Purchaser and PNM agreed to execute and deliver
(or, in the case of Purchaser, to cause San Juan Coal Company, a Delaware
corporation ("SJCC"), to execute and deliver, as applicable), contemporaneous
with the closing (the “Closing”) of the contemplated acquisition of one hundred
percent (100%) of the issued and outstanding shares of SJCC and San Juan
Transportation Company, a Delaware corporation, by Purchaser from BHP Billiton
New Mexico Coal, Inc., a Delaware corporation (“Seller”), the Coal Supply
Agreement, including the Guaranty substantially in the form attached thereto,
the Reclamation Services Agreement and the Coal Combustion Residuals Disposal
Agreement, each substantially in the form submitted by PNM to the New Mexico
Public Regulation Commission (the “PRC”) on a confidential basis on May 1, 2015
(collectively, the “Coal Agreements”).

Pursuant to an Order Setting Further Proceedings issued by the PRC on May 27,
2015, PNM is now required to submit fully executed Coal Agreements to the PRC by
July 1, 2015 rather than executing said agreements as of the Closing.

Effective as of the due execution and delivery of the Coal Agreements by PNM and
Purchaser, the Letter Agreement is hereby terminated and of no further force and
effect.

This Letter Agreement Termination may be executed by facsimile or portable
document format (.pdf) and in one or more counterparts, all of which shall be
considered one and the same agreement and each of which shall be deemed an
original.

{Signature Page to Follow}

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IN WITNESS WHEREOF, the Parties hereto have caused this Letter Agreement
Termination to be executed on their behalf by their respective officers,
thereunto duly authorized.

PUBLIC SERVICE COMPANY OF NEW MEXICO

By: /s/ Chris M. Olson            
Name:    Chris M. Olson            
Title:    Vice President, Generation        

WESTMORELAND COAL COMPANY

By: /s/ Jennifer Grafton            
Name:    Jennifer Grafton            
Title:    Secretary, Sr. VP