The Bingham Canyon mine and associated Copperton Concentrator operations are a significant copper and molybdenum producer. Molybdenum is present in the deposit as the sulphide mineral molybdenite. In 2004, the price of molybdenum increased 10-fold resulting in a renewed emphasis on production of this metal, including efforts to optimize its flotation recovery. Molybdenite recovery in the bulk flotation circuit is consistently lower than that of the copper sulphides as well as being far more variable. This paper describes the systematic use of size recovery data. quantitative mineralogy and surface analysis to identify the factors contributing to molybdenite recovery relative to copper in the Copperton bulk flotation circuit. Several operational changes have been made to capitalize on the findings of the research these include the separate treatment of an ore type containing problematic silicate minerals and the optimization of the frother to collector ratio to ensure adequate froth stability. (C) 2008 Elsevier Ltd. All rights reserved.