Abstract-This article demonstrates the ability of on-line optimization of cone crushers, specifically maximization of the total throughput of the crusher by adjusting the eccentric speed (ω). The on-line optimization was based on the ExtremumSeeking Control (ESC) approach, which is advantageous when optimizing systems with unknown time varying characteristics. Two types of gradient based approaches are tested in simulation, the traditional Band-pass filters method and a method utilizing the Extended Kalman Filter (EKF). Both methods perform satisfactory, demonstrating the good potential of ESC for online-optimization of cone crushers. To deal with unwanted behavior of the EKF based approach for situations when the gradient is not correctly estimated, a modification is suggested based on detecting this condition and accommodating for it.