Pashpap

RIO TINTO ZINC MINING COST ANALYSIS SYSTEM, PERFORMANCEANALYSIS: JUNE 10, 1975, P. 152.ENGINEERING AND MINING JOURNAL, SOUTH AMERICAN AND CARIB-BEAN: V. 176, NO. 1, 1975, P. 78.MINING MAGAZINE, AMERICAS: PERUVIAN COPPER: V. 133, NO. 6,MINING MAGAZINE, THE MINERAL INDUSTRY OF PERU: V. 131,NO. 4, 1974, P. 262-285.MEMORANDUM, U, S. BUREAU OF MINES, WASHINGTON, D. C.: DEC-EMBER 16, 1974.WORLD MINING, NOVEMBER 1973.