POWER OF ATTORNEY

STATE OF TEXAS         )(

                                     KNOW ALL MEN BY THESE PRESENTS:

COUNTY OF DALLAS       )(

THAT I, Richard W. Cardin, a Director of United States Lime & Minerals, Inc., a
Texas corporation, hereby constitute and appoint Timothy W. Byrne and M. Michael
Owens as my true and lawful attorneys-in-fact and agents, with full power of
substitution and resubstitution, to sign for me and in my name, place, and
stead, in any and all capacities, any and all forms required to be filed by me
pursuant to Section 16(a) of the Securities Exchange Act of 1934 and the rules
promulgated thereunder and any and all amendments to such forms and to file the
same with the United States Securities and Exchange Commission. I further hereby
ratify and confirm any and all actions, matters, and things that such
attorneys-in-fact and agents shall lawfully do or cause to be done by virtue of
this Power of Attorney and the rights and powers granted herein.

         EXECUTED this 15th day of November, 2002

                                              /s/ Richard W. Cardin
                                              -----------------------------


STATE OF TEXAS          )(
COUNTY OF DALLAS        )(

         This instrument was acknowledged before me on the 15th day of November,
2002 by Richard W. Cardin.

                                              /s/ Nita Webb
                                              -----------------------------
                                              Notary Public
                                              State of Texas

                                              My Commission Expires:
                                              S10/12/03