At St Eloi, 172 Company was relieved by the 1st Canadian Company in spring 1916. The shelling and mortar fire made work extremely difficult and in August 1916 the Canadians began a new shaft, named Queen Victoria, well back from the front line. In less than three weeks they had sunk it below 100ft (30.5m). Progress was slowed by continuous cavings, but the Canadians were able to locate and reconnect the old 172 galleries dug for the 27 March 1916 attack. The gallery was driven beyond the Nos 2 and 3 craters and prepared for charging. The charge of 95,600lbs was thought by the British to be the largest of the war (the German charge at Vauquois of 14 May 1916 exceeded it by 5,500kg). Tamping was completed on 28 May 1917, only nine days before firing. A second drive was begun towards craters 2 and 3, but could not be completed in time.²⁷