Spring 1916 saw the 182nd Tunnelling Company move to Berthonval and the construction of subways in Zouave Valley on Vimy Ridge. Vimy was an area of busy underground activity for much of the war. British tunnellers had taken over mining in the area progressively from the French between February and May 1916. From spring 1916, the British had deployed five tunnelling companies along the Vimy Ridge, and during the first two months of their tenure in 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 sector of the Western Front. In May 1916, a German infantry attack, which forced the British back , was aimed at neutralising British mining activity by capturing the shaft entrances. From June 1916, however, the Germans withdrew many miners to work on the Hindenburg Line and also for work in coal mines in Germany. In the second half of 1916 the British constructed strong defensive underground positions, and from August 1916, the Royal Engineers developed a mining scheme to support a large-scale infantry attack on the Vimy Ridge proposed for autumn 1916, although this was subsequently 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 .