Beating the Patient Weapon

Landmine removal in World War II

Our previous article (The Patient Weapon), written on the occasion of International Day for Mine Awareness and Assistance in Mine Action, was about the landmines used by the Third Reich in World War II. This article follows up by discussing the methods used in the war to remove mines. The belligerent nations of the war put their full range of abilities, from sheer human grit through electronic devices to heavy machinery to finding and removing or destroying the enemy’s minefields.

The simplest way to find a mine is, obviously, to have men crawl or walk along and search for them manually. Sticks and bayonets were pushed into the ground at regular intervals in hopes of hitting a mine. The tool had to be held at a flat 30° angle to hit the mine’s side, rather than push down on the top and risk detonation. 

Once a mine was found, disarming it or removing it to a safer location was still a dangerous proposition. Many mines had not one but up to three mine wells (the holes in which a fuze was inserted): one was used for the pressure sensor or tripwire that detonated the mine normally, while the other two could be used for anti-handling devices, additional fuzes that activated when someone tried to pick up or disarm the mine. Such a fuze could be attached to a thin wire which would pull on it when someone moved the mine. Another fuze could be underneath the mine, invisible to the eye, constantly pushed down by the mine’s weight; once the mine was lifted, it would activate. Other mechanical fuzes could be triggered by vibration or the tilting of the mine, while yet others were triggered by the electromagnetic field of a mine detector.

One particularly appalling way of finding and removing mines mechanically was to drive people across a minefield and detonate the mines by stepping on them. German forces on the Eastern Front are known to have forced civilians into minefields, one particular incident in 1943 killing 2-3,000 victims.
 
A common myth claims that the Soviet Union did the same thing with its own soldiers. Now, we can’t say for sure that has never, ever happened, but the idea seems to be based on an old case of Chinese whispers. During the Cold War, Eisenhower (The Supreme Commander) wrote about a conversation he once had with Soviet Field Marshal Georgy Zhukov. What Ike really quoted Zhukov as saying was “There are two kinds of mines; one is the personnel mine and the other is the vehicular mine. When we come to a mine field our infantry attacks exactly as if it were not there. The losses we get from personnel mines we consider only equal to those we would have gotten from machine guns and artillery if the Germans had chosen to defend that particular area with strong bodies of troops instead of with mine fields. The attacking infantry does not set off the vehicular mines, so after they have penetrated to the far side of the field they form a bridgehead, after which the engineers come up and dig out the channels through which our vehicles can go.” The truth of Zhukov’s words seems to have been lost in translation and amid the Russophobia of the Cold War. In fact, Zhukov insisted on giving ordinary riflemen sapper training, exactly so they could start cleaning up minefields on the advance while minimizing losses.
 
Dogs were also used to find mines, though with varying success due to an insufficient understanding of their abilities. (“Let Slip the Dogs of War”)
 
Another way of finding mines was through technology. When an alternating magnetic field (produced by a device) gets close to a piece of conductive metal, the metal will start creating its own magnetic field, which in turn can be detected. This principle was demonstrated as early as 1841. In 1881, Alexander Graham Bell, the inventor of the first practical telephone, used such a device in an attempt to find a bullet lodged in the body of U.S. President James Garfield after an assassination attempt. The experiment failed, as the bed the president was lying on had metal springs which threw off the readings. In the same year, submarine mine pioneer and former Civil War Confederate officer Ambrose McEvoy applied for a patent on a device that used electric induction to find submerged metal sea mines. World War II mine detectors, however, owe their existence to Polish engineer Józef Kosacki.

Working on secret electronic devices for the Polish Army, Kosacki fled to Great Britain after the fall of his homeland in 1939. He invented what became known as the “Polish mine detector,” the first easily portable military mine detector which continued to see use as late as the Gulf War in 1991. The device first saw use at the Second Battle of El Alamein, where it enabled units to advance across minefields at 200 meters (220 yards) per hour, twice what it was before. Kosacki’s name as the inventor of the mine detector was classified during the war and all of his patents were filed under pseudonyms to protect his family, who were living in German-occupied Poland.

There were also unused prototypes of vehicle-mounted Polish mine detectors, which were held in non-metallic drums at the end of arms attached to a Sherman tank (The M4 Sherman) or a Staghound armored car, with the mine detecting crew safely inside.
 
What can you do with a mine once you find it? Disarming it by hand is perilous, so it’s no surprise that the combatant nations of World War II developed machines that could remove or detonate them without endangering humans. One way to do it was to mount a plow in front of a tank or another vehicle: the plow would dig up the mine and push it off to the side, creating a safe corridor. Experiments with mine plows already began late in World War I with Renault FT tanks. Several designs were used in World War II, perhaps most notably the Bullshorn plow that was could be attached to the front of the British Churchill tank. (The Tortoise in the Race) One such Churchill was used on D-Day on Sword Beach as part of the special engineering vehicle unit known as Hobart’s Funnies. (Hobart’s Funnies) Mine plows are still used today, and, if anything, they’re more useful than ever. Modern mines usually have shaped charges that concentrate the blast in a single direction. If a plow can turn the mine upside down, any later explosion will be directed downward into the ground, with little if any damage above.

The Mine roller was another device originally invented in World War I. Rather than pushing mines aside, the heavy rollers mounted in front of the tank pushed against them with enough force to cause them to detonate before the tank itself could roll over them. Rollers usually had ridged or spiked surfaces to increase ground pressure and make it more likely that the mine would explode. One drawback of some roller designs was that they were only mounted in front of the track, but the center of the tank’s front was left unprotected, so it was still possible to be disabled or destroyed by a mine with a tilt-rod fuze.

The most common American mine roller was the T1E3 Mine Exploder Unit attached to Sherman tanks. It was nicknamed “Aunt Jemina” because of its resemblance to Aunt Jemina-brand pancakes. The Soviets and the British also had various types or rollers, including the evocatively named “CIRD”, the Canadian Indestructible Roller Device. What made the CIRD special was that it was mounted in such a way that the force of an explosion could throw it up in the air. This absorbed much of the power of the blast, reducing the chance of damage to the roller itself.

The Germans also experimented with a similar concept, but instead of putting rollers in front of a vehicle, they just tried to design a vehicle so well-armored it could simply roll over and set off mines without harm. The Minenräumer was a three-wheeled prototype whose thick wheels were protected by armored “boots” that would take the brunt of the blast and could be replaced easily. A much larger vehicle, the multi-segmented 130-ton Räumer S was also designed around the same idea of deliberately rolling over mines. (For comparison, the hulking Tiger II weighed ‘only’ around 70 metric tons.)

One drawback of the mine roller was that if it was damaged by a mine, it had to be replaced by a brand new one. The mine flail overcame both this problem and the issue of some mine rollers only protecting the tracks. A spinning drum was mounted in front of the tank with chains hanging from it, and fist-sized balls at the end of each chain. Once the drum was spun up, the chains would rapidly strike the ground with enough force to either destroy or detonate mines buried up to 5 inches (13 cm) deep. The explosion from a larger mine, such as a German Teller mine, could destroy a single chain, but only that chain would need to be replaced rather than the entire device.
 
The mine flail was invented by two people independently from each other. South African Captain Abraham du Toit was the first to come up with the idea, and was sent to Britain to develop it further. Later in the war, another South African officer who did not know about du Toit’s secret work had the same idea.

The first tank to carry mine flails was the British Matilda infantry tank, which was nicknamed “Matilda Scorpion” in this configuration because of its shape. 25 Matilda Scorpions were used at the Second Battle of El Alamein to cut paths across German minefields. They proved reasonably effective, but the flails broke down frequently, and the sand kicked up clogged the air filters and caused the engines to overheat, forcing most of the demining to be done by infantry. On the upside, the terrifying noise, strange appearance and massive dust cloud of the Scorpions caused several German units to surrender on sight.
 
Later versions of the Scorpion were based on the M3 Grant, which was being phased out of combat service in favor of the Sherman, and therefore available in large numbers. After several experiments, the Sherman Crab emerged as the primary mine flail design. The Crab had 43 chains spinning at 142 rpm, and had wire cutters to cut through wire obstacles that otherwise could have entangled the flail. The Mark II version incorporated a counterweighed jib: if the tank came to a dip in the ground, which was a prime spot to place a mine in, the flail drum would automatically dip downward to churn up the spot.

The Crab also had ways of marking safe areas. Each tank carried a bin on each side filled with powdered chalk that gradually trickled out, marking the tank’s path with a pair of white lines. It also had a hopper launching smoke grenades, and a system that shot illuminated poles into the ground so infantry and other vehicles would see the safe path even at night. Sherman Crabs also had a pair of lit masts mounted on them. This helped adjacent Crabs see each other’s position even in the midst of all the dust being kicked up, which was important to keep the formation tight and avoid leaving uncleared gaps.

One weakness of mine flail vehicles was that they were extremely slow while the flail was deployed, the Sherman Crab crawling along at a mere 1.25 mph (2 km/h). This forced them to work in conjunction with mine rollers, which could maintain a much higher speed: vehicles with rollers first located minefields, then flails were brought in to clear passages through them.

After World War II, in the 1950s, some old Churchill tanks got a new lease on life as mine-clearing vehicles with the Churchill Toad, another mine flail vehicle. Mine flails continue to serve to this day, though modern ones are not meant for combat duty and cannot withstand the rigors of battle. Instead, they are used in areas which no longer see fighting but still have minefields that endanger local lives.
 
There were many other attempts to clear minefields. The Snake and Conger devices developed by the British Commonwealth were variations of the Bangalore torpedo. The Snake was a set of rigid tubes that could assembled up to a total length of 131 yards (120 m) and pushed forward into a minefield. The explosive inside the tube would be then detonated, and would, in turn, activate nearby mines, creating a safe path 11.5 to 15 ft (3.5 to 4.5 m) wide. The Conger was a flexible hose that could be launched from a Universal Carrier across the minefield, filled with liquid explosive, and blown up for a similar effect.