Australia’s First World War tunnellers are best remembered for detonating a pair of cataclysmic mines beneath Hill 60 and the Caterpillar on the Messines Ridge on June 7, 1917.
As two of 19 simultaneous explosions at 3.10am under German front-lines, they left massive craters filled with dead and rubble and heralded the start of the Battle of Messines.
However, as Damien Finlayson wrote in Crumps and Camouflets, the miners who comprised three Australian tunnelling companies also took part in battles such as Fromelles, Passchendaele, Amiens, and during the final days before the Armistice in 1918.
In fact, while Australian infantry divisions rested after October 5, the tunnellers came under fire and suffered casualties as late as November 4 when supporting advancing American and British troops by repairing roads and building bridges.
Finlayson said about 300 of the 4500 Australian tunnellers were killed in the Western Front’s war within a war, some as they dug in dark, suffocating and cramped conditions more than 30 metres underground.
They had left Australia with a supply of boring equipment, petrol engines, portable electricity generators, lighting, ventilation fans, and water pumps.
In November 1916, Australian miners took over from Canadians to protect and maintain the Hill 60 and Caterpillar mines set under high ground beside the Ypres to Comines railway cutting.
In the Battle of Messines, historian Craig Deayton said the narrow tunnels typically dug at Messines were just over a metre high by half-a-metre wide and hundreds of metres long.
“The journey to and from the end of the tunnel by dim candlelight was strictly for the fearless.”
In the countdown to June 7, the Australians listened with increasing tension for activity by German miners, sometimes just metres away.
Australian engineer Captain Oliver Woodward said later he was “as immovable as a statue and cold from fear” because it seemed that at any moment “we could expect the bottom of the enemy’s shaft to fall away and precipitate earth and enemy on top of us.”
Woodward had the responsibility of throwing the switch to blow up Hill 60 and the Caterpillar.
The leads stretched hundreds of metres from his firing dugout to 24,300 kilograms of explosive beneath Hill 60 and 32,000 kilograms of explosive under the Caterpillar.
Detonating all 19 mines at once caused the biggest man-made explosion in history at that time.
Observers called it “a giant earthquake with an immense wall of fire.”