A mining machine such as a mining shovel includes a digging assembly having an upward extending boom and a dipper assembly generally horizontally supported by the boom and configured to crowd toward and retract from a vertical bank at a mine site. To determine if the dipper assembly strikes the bank, an electronic controller can calculate a calculated crowd force based in part on a crowd motor torque associated with a crowd motor, a crowd speed of the dipper assembly, and an inertia parameter. If the calculated crowd force exceeds a predetermined first crowd threshold, the electronic controller can register an impact event. In further aspects, the electronic controller can execute a force modification function to modify the crowding forces and a speed reduction function to reduce the crowd speed.