CALC-SILICATE ALTERATION AND ORE CHARACTERIZATION, ASARCO MISSION COMPLEX, IMPLICATIONS ON THE OPTIMIZATION OF MO RECOVERY

This study sought to better understand and characterize the skarns and associated Mo mineralization at ASARCO’s Mission Complex. High grade Mo mineralization generally occurs in three modes: 1) disseminated masses in Clinopyroxene-Tremolite (± calcite, anhydrite) hornfels, 2) trace amounts in Garnet ± Clinopyroxene skarn locally closely associated with scheelite, and 3) as fracture controlled mineralization. Vein paragenesis plays an important role in ore characterization, which varies considerably throughout the deposit. Understanding the relationships between mineral assemblages in specific lithologies associated with Mo is the key to predicting and mitigating potential processing issue.