The common impression of land mines concerns a group of small explosive devices placed near the surface of the ground under just a thin layer of earth, or under some other concealing surface, such as leaves. This has been the dominant approach from World War II to the present, and it is one that makes sense in circumstances with significant battlefield mobility. When the attacker could strike in many places with limited warning, and the defender cannot reinforce all likely targets, land mines of this sort can blunt an attack or slow it down. This kind of mobility did not apply on the Western Front of World War I, however, and mining referred to a very different sort of activity. During the First World War, the use of land mines referred primarily to the digging of tunnels beneath enemy trenches and strongpoints, and igniting large charges of explosive.
The use of mines in any capacity did not become an issue until the end of 1914, when the mobility of the Battle of the Frontiers had broken down, and impromptu fortifications appeared everywhere from Switzerland to the English Channel. With the support of machine guns and artillery, even simple earthworks became formidable defenses. Both sides looked to the available technology for a tool that could assist in an attack on prepared defenses. Explosives were the obvious answer; the question remained, however, of the best way to deliver those explosives where they might have a telling effect.
In November, the possibility of having men carry small charges to the enemy lines for a surface detonation was considered, but the digging of tunnels below the target was soon found to be a more practical solution. The practice of undermining an opponent’s walls had long been a feature of medieval siege warfare, and in many respects, the static warfare of the Western Front had come to resemble a medieval siege. Under these circumstances, many archaic practices were revived, from the wearing of helmets and body armor to the use of clubs. With the availability of modern explosives, the practice of mining promised to be more effective than ever.
It was not without recent precedent. Mining had been used spectacularly in the Siege of Petersburg during the American Civil War, even if poor follow-up had left the effort largely ineffectual. There, too, the Confederates had dug extensive earthworks, and the besieging Union troops sought a way to break open the defenses. Mining required a significant amount of time in preparation for the attack, but in a siege context, attackers had the time they needed. The greatest advantage over the placement of charges on the surface lay in the quantity of explosives that could be delivered. Men scurrying across No-Man’s Land by night could carry only a small charge, and even if it were placed perfectly, it could force only a small breach. A more carefully-prepared mine underground could allow for very large detonations, like the one at Petersburg in 1864. If exploited more effectively than Petersburg, such a detonation could be decisive.
The Petersburg detonation had resulted in an enormous crater in the midst of the Confederate earthworks, and mining efforts in World War I offered comparable results. Hand-delivered charges on the surface would limit the amount of explosives to a weight that a single man could reasonably carry; even considering the advances in munitions technology in the ensuing fifty years, such a small charge would have a limited effect on a difficult section of fortified ground. Mines collected underground were under no such limitation. A single mine built underground could contain a massive collection of explosive material, with even 300 lbs of explosives rating as a small charge when compared with the larger mines in the war. Moreover, a given operation did not depend on the success of a single mine. Typically, a series of tunnels were dug under a fortified zone, and each was mined, with the intention of blowing all of them in a simultaneous wave of destruction.
Interestingly, considering their tactically defensive posture for most of the war, it was the Germans who first used mines. They dug eleven mines beneath a British-held position at Festubert, delivering mines up to 300 lbs in weight in each. They were ignited on December 20, 1914, and ten of them exploded successfully. A brigade of Indian troops perished at once. For the morale of their own troops, the British and French were compelled to invest in the creation of teams capable of making their own mines.
In addition to the obvious offensive use of mines, this effort also included the defensive practice of counter-mining. As the war progressed, supporting devices like the geophone, enabling tunnelers to hear the approach of enemy tunnelers as the mine drew near its intended target. Defenders sought to foil enemy mines by building another mine beneath the attackers’ mine, and then setting off a small explosive charge, called a camouflet, under it. The camouflet was much smaller than the offensive mine, only being large enough to collapse the mine above it. In practice, the effort was not always so straightforward. Frequently, the opposing sides would meet unexpectedly, with a chaotic melee resulting.
It took some time for the French and British to catch up with the Germans in their mining practices, but during the summer of 1916, the Entente powers began to exceed the Germans. The French and the Germans used mining extensively in the Vauquois section of the front, where in one blast the Germans used sixty tons of Westfalit explosives on May 14. Eventually the British exceeded both through the cultivation of specialists drawn from professional miners. The hazards of operating in a war zone posed unfamiliar challenges to those who had been miners in civilian life, and so it took some time for these specialist units to prepare for their jobs, but once they had acclimated themselves to the task, they were a formidable force. Armed with TNT as their explosive of choice, British and other Dominion miners blew devastating mines in the Somme and Ypres campaigns.
Besides all of the hazards faced by the miners themselves, from cave-ins and toxic gases to enemy camouflets, the use of mines posed risks to friendly soldiers above if the detonation of the mines were not adequately coordinated with an attack. Ideally, the mines would blow at a time that would permit the attacking force to reach the crater before enemy troops could rally, and so a section of trench or a fortification could be seized. With poor coordination, the enemy could send in reinforcements and hold a new zone of difficult terrain before the attack arrived; or worse, friendly soldiers could be killed in the explosion if it were ignited too late. Given all of these elements, there was only one example of mining that proved strategically decisive: the British mines under Messines Ridge in the Ypres campaign of 1917.
At Ypres, the mining was unusually extensive, with twelve separate tunnels being dug over the course of a year, one of them exceeding 2,000 feet in length. Twenty-one mines were laid, with the total weight of explosives approaching 500 tons. The charges were ignited on June 7, 1917, with nineteen of the mines exploding according to plan. An estimated ten thousand Germans were killed in blasts that could be heard as far away as southern England. Here, the British were able to claim the ridge and push the German line back.
While the use of mining continued, it never again had as potent an effect as it did at Messines Ridge; for that matter, developments in the use of tanks and aircraft offered the prospect of a resumption of mobile warfare. The German spring offensives of 1918, followed by the Allied summer offensives, saw a fluidity on the battlefield that had not been present since the end of 1914. The Germans attempted to disable Allied tanks by burying mortar shells in shallow holes dug across an area likely to see a tank attack, anticipating the minefields of World War II and beyond.
The enormous underground mines of World War I had been a response to static warfare, and the practice did not generally continue in future wars, where battlefield mobility became a normal condition again. Like the minefields of later wars, however, the mines of World War I sometimes remained to pose a threat to future generations. Not all mines exploded as planned, as seen in battles from Festubert to Messines Ridge. Of the two mines at Ypres that failed to blow, one was triggered in 1955 as a storm raged in the area.
Sources:
Forty, Simon. World War I: A Visual Encyclopedia. PRC Publishing, 2002
Haythornthwaite, Philip J. The World War One Source Book. Arms & Armour, 1996
Sheffield, Gary. War on the Western Front: In the Trenches of World War I. Osprey, 2008
Strachan, Hew. The Oxford Illustrated History of the First World War. Oxford, 2001
Westwell, Ian. The Complete Illustrated History of World War I. Anness Publishing, Ltd., 2008
Willmott, H.P. World War I. Covent Garden Books, 2003
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