POWER OF ATTORNEY
I, Carlo Orsenigo, hereby appoint William
Brierly, Sarah K. Hilty and/or Carrie Etherton, my true
and lawful attorney-in-fact to:
1. Execute for me and on my behalf Forms 3, 4, and 5
and any Amendments thereto, in accordance with Section 16
of the Securities Exchange Act of 1934, as amended, and
the rules thereunder;
2. Do and perform any and all acts for me and on my
behalf which may be necessary or desirable to complete
and execute any such Forms 3, 4, and 5 and any
Amendments thereto and timely file such Forms and
Amendments with the Securities and Exchange Commission;
and
3. Take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of
the attorney-in-fact, may be of benefit to, in the best
interest of, or legally required by me, it being
understood that the documents executed by the
attorney-in-fact on my behalf pursuant to this Power
of Attorney shall be in such form and shall contain
such terms and conditions as the attorney-in-fact may
approve in his discretion.
I hereby grant to the attorney-in-fact full power
and authority to do and perform any and every act and
thing whatsoever requisite, necessary, or proper to be
done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes
as I might or could do if personally present, with
full power of substitution or revocation, hereby
ratifying and confirming all that the attorney-in-fact,
or the attorney-in-fact's substitute or substitutes,
shall lawfully do or cause to be done by
virtue of this Power of Attorney and the rights and
powers herein granted. I hereby acknowledge that the
foregoing attorney-in-fact, in serving in such capacity
at my request, is not assuming any of my responsibilities
to comply with Section 16 of the Securities Exchange Act
of 1934, as amended.
This Power of Attorney shall remain in full force
and effect until I am no longer required to file Forms 3,
4, and 5 and any Amendments thereto, unless I earlier
revoke this Power of Attorney in a signed writing
delivered to the attorney-in-fact.
IN WITNESS WHEREOF, I hereby cause this Power of
Attorney to be executed as of this 11th day of May
2017.
/s/Carlo Orsenigo
___________________________________
Carlo Orsenigo
Executive Vice President
