A mine flail is a vehicle-mounted device that makes a safe path through a minefield by deliberately detonating land mines in front of the vehicle that carries it. They were first used by the British during World War II.
The mine flail consists of a number of heavy chains ending in fist-sized steel balls (flails) that are attached to a horizontal, rapidly rotating rotor mounted on two arms in front of the vehicle. The rotor's rotation makes the flails spin wildly and violently pound the ground. The force of a flail strike above a buried mine mimics the weight of a person or vehicle and causes the mine to detonate, but in a safe manner that does little damage to the flails or the vehicle.