The mine was started by 250 Tunnelling Company in late 1916 and was probably the most ambitious of the Messines Ridge scheme.
It consisted of two ‘tubbed’ shafts 200 feet apart at the British trench known as Park Avenue due west of Wytschaete. A Circular steel shaft or ‘tubbing’ was used when the ground was very wet and of poor quality. These were steel rings sealed with strips of rubber cut from car tyres and the gap between the sleeves filled with concrete. It was first used in French Flanders at Cuinchy in 1915 where 170 Tunnelling Company successfully sank a 1.8 metre diameter timber shaft through two metres of running sand to the dry clay bed. On hearing of this, Norton-Griffiths gave instructions to the officer in charge, Lieutenant A J Leeming, to obtain a round iron cylinder in order to ‘tub’ the interior of the shaft to permanently seal it from water and sand. Norton-Griffiths also arranged for steel tubbing to be manufactured first in France and later in the UK to be supplied to the tunnellers.
The two shafts were connected at 50 feet deep and just off this connection two further interior shafts were sunk to a depth of 80 feet and the forward drives begun, the drive from No.1 shaft turning to meet No.2. The two galleries ran out parallel to each other with No.2 gallery turning to the right towards its target of Maedelstede Farm and No.1 gallery proceeding toward its target of Wytschaete Wood a distance of some 2,600 feet and well behind the German front line.
In early 1917 the Germans fired a number of camouflets in the area. It was not known whether the British mining had been discovered so, as a precaution the men were withdrawn for three hours each day. This precaution, and the need to tram the spoil from the two galleries back at night and then camouflage it from enemy observation caused delay. After No.1 gallery had gone a distance of 1,320 feet it was realised that it was not going to reach its objective in time and was abandoned. All effort now went into No.2 gallery and at 1,610 feet it reached its target of Maedelstede Farm where it was chambered, and 94,000 lbs (42,637 kg) of ammonal was charged, tamped, and reported as ready on 6 June 1917, one day before zero.
