The performance of a hydrocyclone as a separation device is never perfect and rigorous research efforts are still continuing along various directions towards achieving optimum solutions. The modus operandi of performance optimization is important for quick and non-invasive monitoring of hydrocyclone performance. Therefore, in the present study, an application potential of spray angle as a performance monitoring tool has been explored to investigate the operation state of a hydrocyclone. In this context, phenomenological features of spray discharge over a wide range of injection pressure and feed solid concentration have been investigated. The emphasis of the present study is to verse the amendment of the hydrocyclone operational state with the corresponding change in underflow discharge pattern. The pattern of the underflow discharge profile was captured using a digital camera and analyzed based on an image processing algorithm to detect the discharge angle under different operating and design conditions. Stability and reproducibility of the spray angle at fixed operating condition have also been confirmed. Subsequent analysis shows that the spray angle is sensitive to variations of operating and design variables. More specifically the effect of feed slurry concentration has been characterized and is of major importance for the transition to roping. On this basis, an attempt has also been made to develop an empirical correlation based on experimental data. The developed correlation shows that the discharge angle could possibly be used as a reliable tool to monitor hydrocyclone performance. (C) 2016 Elsevier B.V. All rights reserved.