Hydrocyclone-thickener circuit is a promising solution to enhance the dewatering efficiency in mineral industries. The major challenge in the circuit is reducing particle size in the thickener feed and the opportunity is a rise in the residence time of sediments. In this work, the effect of particle size, bed depth and residence time on the pilot thickener performance were investigated. Furthermore, the influence of residence time was differentiated due to the variations in the bed depth and settling flux. Moreover, a new approach was introduced to estimate solids residence time in the thickener. Results indicated that a significant drop in the thickener performance was observed by reducing the particle size. Additionally, it was found that longer residence time and deeper bed increased the thickener performance while the bed depth had a stronger effect.