Molybdenum (Mo) stable isotopic variations as indicators of Mo attenuation in mine waste-rock drainage

摘要

Measurements of molybdenum (Mo) stable isotopes (delta Mo-98) were applied along with conventional geochemical analyses of water and rock samples at a Mo mine in the USA to assess controls on Mo mobility in two unsaturated waste-rock storage facilities (WRSFs) that are differentiated by acidic and alkaline drainages. Unweathered waste rock, Mo ore, and mine tailings from the site were also analyzed to constrain the isotopic composition of the source of Mo entering mine drainage via weathering processes. The surfaces of weathered waste-rock samples were sequentially leached using a two-step chemical extraction to determine the distribution and isotopic composition of Mo among primary and secondary mineral assemblages.