Before revision: Typically, the shear-pin in an anti-tank mine is designed to snap (and release the spring-loaded firing pin) when a weight in excess of 150 kilograms is applied to the pressure plate.
After revision: Typically, the shear-pin in an anti-tank mine is designed to snap (and release the spring-loaded firing pin) when a weight in excess of 1500 kilograms is applied to the pressure plate.