Conventional anti-tank mines, typically the size of a dinner plate and weighing 12kg, are usually laid in fields immediately in front of defensive positions, marked with barbed wire and warning signs. They are sometimes buried, but more often just left on the ground. America developed scatterable mines in the 1960s, during the Vietnam war. These weigh only one-fifth as much as traditional mines, but are still powerful enough to destroy a tank; they are triggered by magnetic sensors that detect vehicles passing over them. At first they were dropped from aircraft or helicopters; later they were deployed via special artillery rounds. Commanders could thus create minefields behind enemy lines, to block or channel troop movements or simply to inflict casualties. The Soviet Union fielded its own versions soon after the Americans.
Read more of our recent coverage of the Ukraine war
Such mines are scattered randomly; a 155mm howitzer shell distributes nine in a rough circle 200 metres in diameter. The Ukrainians use American-supplied scatterable mines to seal gaps in minefields and cut off advancing Russian forces. Drone delivery turns such mines into precision munitions. As the Birds of Magyar showed, they can accurately mine roads and tracks most used by the enemy. A multicopter “heavy bomber” can lay six or more mines from 20km away, several times a night—although constant mining is needed to keep a route closed, which takes heavy drones away from other missions.
Mines on roads are difficult to see in the dark, especially when driving at high speed without lights for fear of attack. They are more visible in daylight, although videos show careless drivers running into them. Russian sappers clear them each morning. Shooting is not a reliable way of setting off or disabling them. And clearing by hand is dangerous because the magnetic sensor may be triggered by someone carrying metal objects. Some mines are disguised with plastic leaves or other camouflage, and many have other sensors that go off if moved. Increasingly, robots and drones are being used to remove as well as lay them; a technical race between minemakers and deminers is under way.
Birds of Magyar were highly satisfied with their mining campaign and launched a fundraising campaign for 20,000 Ukrainian drone-dropped copies of Russian mines at $50 each. Ukraine is also fielding a new more effective type, the PTM-L1, based on an American design with a modern fuse.
Both sides are also using drones to drop smaller anti-personnel mines. (The Russians scatter tiny “Petal” mines in civilian areas of Kharkiv, too, in a campaign to drive out the population.) A huge effort goes into protecting troops from drones, with jammers, shotguns and other weapons. But this is useless if the drones bypass them and lay mines to cut off their lines of supply and retreat. Mine warfare has always been about reducing mobility; mines laid by drones make movement even more difficult and more dangerous, for both soldiers and vehicles. Drone-dropped mines may thus reinforce the trend towards a battlefield populated entirely by machines.
