CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002
In connection with the Quarterly Report of Cliffs Natural Resources Inc. (the Company) on Form 10-Q for the period
ended March 31, 2010 as filed with the Securities and Exchange Commission on the date hereof (the Form 10-Q), I, Laurie Brlas, Executive Vice President and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C.
Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to such officers knowledge:
The Form 10-Q fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and
The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Company as of
the dates and for the periods expressed in the Form 10-Q.
April 29, 2010
/s/ Laurie Brlas
Executive Vice President and
Chief Financial Officer