PHELPS DODGE CORPORATION AND SUBSIDIARIES Exhibit 12 COMPUTATION OF TOTAL DEBT TO TOTAL CAPITALIZATION (Unaudited; dollars in thousands) March 31, December 31, 1998 1997 ---- ---- Short-term debt $ 86,200 91,400 Current portion of long-term debt 63,900 54,800 Long-term debt 846,000 857,100 ---------- ---------- Total debt 996,100 1,003,300 Minority interests in subsidiaries 117,600 113,300 Common shareholders' equity 2,651,300 2,510,400 ---------- ---------- Total capitalization $3,765,000 3,627,000 ========== ========== Ratio of total debt to total capitalization 26.5% 27.7% ========== ==========