The advance to the front lines during the night did not go completely as planned. The enemy were well aware of the impending attack and in most cases of the tunneling work to lay the mines. In the Australian sector, the men of the 33rd Battalion made their way through the tracks of Plugstreet Wood and were subjected to bombardment of German gas shells, which resulted in a number of casualties, including some dead, who now lie side by side in Toronto Avenue Cemetery within the wood.
Over the months leading up to the battle, the German's had dug their own tunnels in an attempt to prevent the Allies from laying the mines. In the New Zealand sector, the mine at Petite Douve Farm was discovered by the enemy and the river diverted to flood the underground workings and render the explosives useless. At the northern end of the salient, the hand to hand fighting in the vast tunnel network beneath Hill 60 is well documented. At the southern end, the team from No Man's Land, have been undertaking archaeological investigations in the area attacked by the Australian 3rd Division and in 2011 uncovered the entrance shaft to a German counter tunnel.
Members of No Man's Land excavating a German tunnel shaft.
For the troops of the British Second Army, the blowing of the mines was an awesome sight, for the enemy just a few hundred yards away, it was terrifying. Reports tell of the once stoical men of the German Imperial Army so badly shaken that they were reduced to tears, disorientated and deafened.
However not all had been disabled by the blasts. The geology of the land restricted the placement of the mines and the fortified towns of Messines and Wytschaete escaped the destruction from underground, the mines being placed on the German front line down slope of the towns. Here the New Zealanders and Irish men were engaged in fierce fighting to secure the ruined houses and their fortified cellars.
Twin craters from the mines near to Wytschaete
Due to the loss of the mine at Petite Douve, the New Zealander Division only had one mine in their sector, at Ontario Farm close to the Wulverghem to Messines Road. Here the soil is very sandy and the explosion had very different effects, the shockwave causing the enemy fortifications to sink due to liquefaction, instead of a distinct crater, the sand settled back and the men reported the site of the explosion bubbled like porridge for many days as trapped gases found their way to the surface.