An underground gallery excavated to intercept and destroy the mining of an enemy.

A stratagem or plot by which another sratagem or project is defeated.

To oppose by means of a countermine; to intercept with a countermine.

To make a countermine or counterplot; to plot secretly.

(military) a tunnel dug to defeat similar activities by the enemy

destroy property or hinder normal operations; "The Resistance sabotaged railroad operations during the war"

destroy enemy mines with one's own mines; "We countermined the banks of the river"

A mine placed in a tunnel which can be detonated beneath an advancing enemy to delay his advance. A fortified location may have a permanent system of galleries to use for mines when besieged but conversely, a besieging enemy may dig tunnels of his own to detonate beneath the defenders should they try to leave, or to blow up fortifications from below. In this latter case, it is the besieger who is the counter miner. Mock attacks may also be launched to tempt the enemy to advance onto the mined area. The term can also refer to the hidden access to a trench system.