 In most cases these minefields consist of a combination of anti-tank and anti-personnel mines, with the anti-personnel mines making removal of the anti-tank mines more difficult.Mines of this type used by the United States are designed to self-destruct after a preset period of time, reducing the requirement for mine clearing to only those mines whose self-destruct system did not function.Some designs of these scatterable mines require an electrical charge (capacitor or battery) to detonate.