POWER OF ATTORNEY
For Executing Forms 3, 4 and 5 and Schedules 13D and 13G

    Know all by these presents, that the undersigned hereby constitutes and
appoints each of Denise C. McWatters, Walter W. Zimmerman, and Vaishali S.
Bhatia, signing singly, the undersigned's true and lawful attorney-in-fact to:

(1)    prepare, execute and file, for and on behalf of the undersigned (a) Forms
3, 4 and 5 (including amendments thereto) in accordance with Section 16(a) of
the Securities Exchange Act of 1934 and the rules thereunder and (b) Schedules
13D and 13G (including amendments thereto) in accordance with Sections 13(d) and
13(g) of the Securities Exchange Agent of 1934 and the rules thereunder;

(2)    do and perform any and all acts for and on behalf of the undersigned that
may be necessary or desirable to prepare and execute any such Form 3, 4 or 5
(including amendments thereto) or Schedule 13D or 13G (including amendments
thereto) and timely file that Form or Schedule with the United States Securities
and Exchange Commission and any stock exchange or similar authority, and provide
a copy as required by law or advisable to such persons as the attorney-in-fact
deems appropriate; and

(3)    take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of the attorney-in-fact, may be of benefit to, in
the best interest of, or legally required of the undersigned, it being
understood that the documents executed by the attorney-in-fact on behalf of the
undersigned 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 the
attorney-in-fact's discretion.

        The undersigned hereby grants to each such 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 the
undersigned 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.  The undersigned acknowledges that the
foregoing attorneys-in-fact, and their substitutes, in serving in such capacity
at the request of the undersigned, are not assuming, nor is HollyFrontier
Corporation and its affiliates assuming, (i) any of the undersigned's
responsibilities to comply with Section 16 or Sections 13(d) or 13(g) of the
Securities Exchange Act of 1934 or (ii) any liability of the undersigned for
failure to comply with such requirements.  This Power of Attorney does not
relieve the undersigned from the undersigned's obligations to comply with the
requirements of the Securities Exchange Act of 1934, including without
limitation the reporting requirements under Section 16 or Sections 13(d) or
13(g) thereunder.

       The undersigned agrees that each such attorney-in-fact may rely entirely
on information furnished orally or in writing by or at the direction of the
undersigned to the attorney-in-fact.  The undersigned also agrees to indemnify
and hold harmless HollyFrontier Corporation and its affiliates and each such
attorney-in-fact against any losses, claims, damages or liabilities (or actions
in these respects) that arise out of or are based upon any untrue statements or
omissions of necessary facts in the information provided by or at the direction
of the undersigned, or upon the lack of timeliness in the delivery of
information by or at the direction of the undersigned, to that attorney-in-fact
for purposes of executing, acknowledging, delivering or filing any Form 3, 4 or
5 (including amendments thereto) or Schedule 13D or 13G (including amendments
thereto) and agrees to reimburse HollyFrontier Corporation and its affiliates
and the attorney-in-fact on demand for any legal or other expenses reasonably
incurred in connection with investigating or defending against any such loss,
claim, damage, liability or action.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4 and 5 (including amendments
thereto) and Schedules 13D and 13G (including amendments thereto) with respect
to the undersigned's holdings of and transactions in securities issued by
HollyFrontier Corporation and its affiliates, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys in fact.
This Power of Attorney does not revoke any other power of attorney that the
undersigned has previously granted.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of the date written below.

/s/  Michael C. Jennings
Name:  Michael C. Jennings

November 11, 2015