The First Effective Mine Detector

Land mines have been around in one form or another for over a thousand years. By now, you would think that a simple and secure way to locate and remove devices would have been designed. But this is not the case. In fact, until World War II, the most common way to find explosives was to prod the ground with a stick or pointed bayonet. The hockey puck-sized devices were buried about 15cm underground. When someone stepped on the ground above or near the mine, their weight caused the pressure to be sensed and caused the device to explode. So clearing mines was almost as dangerous as walking into a minefield unaware.

During World War II, landmines were widely used by both Axis and Allied forces and were responsible for deaths 375,000 soldiersaccording to War History Network.

In 1941 Joseph Stanislaw KosakiA Polish signals officer who had escaped to the United Kingdom developed the first portable device to effectively detect a ground mine without accidentally triggering it. It proved faster than previous mine detection methods, and was soon widely used by the British and their allies.

The engineer behind the portable mine detector

Before inventing the mine detector, Kosaki worked as an engineer and developed tools for detecting explosives Polish Armed Forces.

After receiving a bachelor’s degree in electrical engineering from Warsaw University of Technology In 1933, Kosaki completed his mandatory one-year service with the army. Then join National Institute of Communications In Warsaw as director. Then, as now, the agency led the country’s research and development Telecommunications and information technologies. In 1937 Kosacki was commissioned by Polish Ministry of National Defence To develop a machine that could detect unseparated bombs and shells. He completed his device, but it was not used in the field.

Polish engineer Józef Kosacki saved the portable land detector for thousands of soldiers in World War II. Military Historical Office

When Germany invaded Poland in September 1939, Kosaki returned to active duty. Because of his background in electrical engineering, he was placed in a special communications unit that was responsible for maintenance Warsaw II radio station. But this duty only lasted until the radio towers were destroyed by German army A month after the invasion.

With Warsaw under German occupation, Kosaki and his unit were arrested and taken to a concentration camp in Hungary. In December 1939, he escaped and eventually found his way to the United Kingdom. There he joined other Polish soldiers in 1st Polish Army Corps, Stationed in St. Andrews, Scotland. He trained soldiers to use wireless telegraphy to send messages in Morse code.

Then tragedy struck.

Engineering ingenuity inspired by tragedy

The invention of the portable mine detector came after a terrible accident on the beaches of Dundee, Scotland. In 1940, W British ArmyFearing German invasion, thousands buried land mines along the coast. But they did not notify their allies. soldiers from Build 10 Armored Cavalry Corps On routine beach patrol she was killed or injured when the land mines exploded.

This event prompted the British Army to launch a competition to develop an effective land detector. Each participant had to pass a simple test: discover a handful of coins scattered on the beach.

Kosaki and his assistant spent three months improving Kosaki’s bomb detector. During the competition, their new detector identified all the coins, beating the other six devices that entered.

There is some ambiguity about the detector’s precise circuitry, masking technology developed under wartime security, but our best understanding is: The instrument consisted of a single wicker pole that, according to 2015 article in Space research in Bulgaria. The soldier carried the detector by the pole and passed the wooden panel on the ground. The wooden backpack encased a battery module, an audio frequency oscillator, and an amplifier. The transmitting coil was connected to an oscillator, which generated current at an audio frequency, writes Mike Cole in his book History of land mines. The receiving coil was connected to the amplifier, which was then linked to a pair of headphones.

The detector weighs less than 14 kilograms and operates much like the metal detectors used by Beachcombers today. Michał Bojara/National Museum of Technology in Warsaw

When the plate approached a metal object, the inductance balance between the two coils was disturbed. Via the loudspeaker, the receiving coil sent an audio signal to the headphones, notifying the soldier of a possible land mine. The equipment weighs less than 14 kilograms and can be operated by a single soldier, according to Croll.

Kosacki did not patent his technology and instead gave the British Army access to the blueprints for the device. The only recognition he received at that time was a letter from King George VI Thanking him for his service.

Detectors were quickly manufactured and shipped to North Africa, where the German commander Erwin Rommel He had ordered his forces to build a defensive network of land mines and barbed wire, which he called Devil’s Gardens. The minefields extended from the Mediterranean Sea in northern Egypt to the Qatara Depression in western Egypt and included an estimated 16 million mines over 2,900 square kilometres.

Kosacki detectors were first used in… The Second Battle of Almenin Egypt, in October and November of 1942. British soldiers used the device to avoid an explosive minefield. Scorpion tanks followed the soldiers. Heavy chains attached to the nose flew to the ground and detonated the mines when the tank moved forward. The Kosaki mine detector doubled the speed at which these heavily mined areas could be cleared, from 100 to 200 square meters per hour. By the end of the war, his invention had saved thousands of lives.

The Kosaki ground detector was first used in Egypt, to help clear a huge minefield laid by the Germans. The basic technology continued to be used until 1991.National Army Museum

The basic design continued to be used with minor modifications by Canada, the United Kingdom, and the United States until the end of the year First Gulf War In 1991. By then, engineers had developed more sensitive portable detectors, as well as remote-controlled mine cutting systems.

Kosaki was not publicly recognized for his work until after World War II, to prevent reprisals against his family in German-occupied Poland. When Kosaki returned to Poland after the war, he began teaching electrical engineering at the National Center For nuclear research, in Otwock-wierk. He was also a master of what is known now Military University of Technology In Warsaw. He died in 1990. The prototype of the Kosaki detector shown above is in a museum Military Institute of Engineering Technologyin Wroclaw, Poland.

Earth mining remains a problem around the world

Ground detection has gone undetected, and explosive devices remain a major problem around the world. On average, one person is killed or injured by land mines and other explosive ordnance every hour, according to UNICEF. Today, it is appreciated 60 countries are still polluted By mines and useless munitions.

Although portable mine detectors continue to be used, Drones It became another method of discovery. For example, They have been used in Ukraine by many non-profit human organizationsincluding Help the Norwegian people and Halo trust.

Non-profit Apopo He takes a different approach: training rats to sniff out explosives. Herorats Apopo, as they are called, only detect the smell of explosives and discard scrap metal, According to the organization. A single herald can search an area the size of a tennis court in 30 minutes, rather than the four days it takes a human to do so.

Part of a Continuing series Looking at historical artifacts embraces the limitless possibilities of technology.

An abbreviated version of this article appears in the January 2025 print issue as “The first detector in land mines that actually worked.”