page_title: Battle of Vimy Ridge
section_title: Underground operations
hierarchical_section_title: Battle of Vimy Ridge / Prelude / Underground operations
caption_attribution_description: English: Preserved World War 1 fighting tunnel in Vimy sector. Français&#160;: Un tunnel de combat préservé de la première guerre mondiale dans la secteur de Vimy. עברית: מנהרה בריטית
context_page_description: The Battle of Vimy Ridge was part of the Battle of Arras, in the Nord-Pas-de-Calais region of France, during the First World War. The main combatants were the four divisions of the Canadian Corps in the First Army, against three divisions of the German 6th Army. The battle took place from 9 to 12 April 1917 at the beginning of the Battle of Arras, the first attack of the Nivelle Offensive, which was intended to attract German reserves from the French, before their attempt at a decisive offensive on the Aisne and the Chemin des Dames ridge further south.
  The Canadian Corps were to capture the German-held high ground of Vimy Ridge, an escarpment on the northern flank of the Arras front. This would protect the First Army and the Third Army farther south from German enfilade fire. Supported by a creeping barrage, the Canadian Corps captured most of the ridge during the first day of the attack. The village of Thélus fell during the second day, as did the crest of the ridge, once the Canadian Corps overran a salient against considerable German resistance. The final objective, a fortified knoll located outside the village of Givenchy-en-Gohelle, fell to the Canadians on 12 April.
context_section_description: Operations along the Vimy Ridge were accompanied by extensive underground excavations. The Arras–Vimy sector was conducive to tunnelling owing to the soft, porous yet extremely stable nature of the chalk underground. Underground warfare had been conducted on the Vimy sector since 1915. Bavarian engineers had blown twenty mines in the sector by March 1915. By early 1916, German miners had gained an advantage over their French counterparts. British tunnelling companies of the Royal Engineers took over progressively from the French between February and May 1916.
  On their arrival, the British began offensive mining against German miners, first stopping the German underground advance and then developing a defensive strategy that prevented the Germans from gaining a tactical advantage by mining. From spring 1916, the British had deployed five tunnelling companies along the Vimy Ridge and during the first two months of their tenure of the area, 70 mines were fired, mostly by the Germans. Between October 1915 and April 1917 an estimated 150 French, British and German charges were fired in this 4.3 mi (7 km) sector of the Western Front. In May 1916, Operation Schleswig-Holstein, a German infantry attack, forced the British back 700 yd (640 m), to stop British mining by capturing the shaft entrances. In the second half of 1916, the British constructed strong defensive underground positions and from August 1916, the Royal Engineers developed a mining scheme for a big infantry attack on the Vimy Ridge proposed for autumn 1916, although this was postponed. After September 1916, when the Royal Engineers had completed their network of defensive galleries along most of the front line, offensive mining largely ceased although activities continued until 1917. The British gallery network beneath Vimy Ridge eventually grew to a length of 7.5 mi (12 km).
  The Canadian Corps was posted to the northern part of Vimy Ridge in October 1916 and preparations for an attack were revived in February 1917. British tunnelling companies created extensive underground networks and fortifications. Twelve subways, up to 1.2 km (0.75 mi) long were excavated at a depth of 10 metres (33 ft) and used to connect reserve lines to front lines, permitting soldiers to advance to the front quickly, securely and unseen. Often incorporated into subways were light rail lines, hospitals, command posts, water reservoirs, ammunition stores, mortar and machine gun posts and communication centres. The Germans dug a number of similar tunnels on the Vimy front, to provide covered routes to the front line and protection for headquarters, resting personnel, equipment, and ammunition. The Germans also conducted counter-mining against the British tunnellers and destroyed a number of British attempts to plant mines under or near their lines.
  Prior to the Battle of Vimy Ridge, the British tunnelling companies also secretly laid 13 mines under German positions to destroy surface fortifications before the assault. To protect some advancing troops from German machine gun fire, as they crossed no man's land during the attack, eight smaller Wombat charges were laid at the end of the subways to allow troops to move more quickly and safely enter the German trench system by creating an elongated trench-depth crater that spanned the length of no man's land. At the same time, 19 crater groups existed along this section of the Western Front, each with several large craters. To assess the consequences of infantry having to advance across cratered ground after a mining attack, officers from the Canadian Corps visited La Boisselle and Fricourt where the mines had been blown on the First day of the Somme. Their reports and the experience of the Canadians at The Actions of St Eloi Craters in April 1916, where mines had so altered and damaged the landscape as to render occupation of the mine craters by the infantry all but impossible, led to the decision to remove offensive mining from the central sector allocated to the Canadian Corps at Vimy Ridge. Further British mines in the area were vetoed follo
caption: British-dug fighting tunnel in Vimy sector
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