Tunnel warfare

Mining was known from the sieges of old, and on the Western Front it returned when the war turned into a siege along the trench lines. The Germans were the first to lay mines under enemy trenches, in the autumn of 1914; on 20 December they blew ten at Festubert. In February 1915 the British, at the urging of the MP and contractor John Norton-Griffiths, began forming Royal Engineers tunnelling companies from professional miners; by mid-1916 there were 25 British and seven Dominion companies, at their peak about 25,000 men. Both sides dug galleries, mine chambers and countermines and listened for the enemy underground.

The largest mines were fired at the start of great offensives: on 1 July 1916 on the Somme, among them Lochnagar at La Boisselle, and on 7 June 1917 at Messines, where 19 mines with about 450 tons of ammonal killed an estimated 10,000 Germans. Under the hill of Vauquois the French and Germans fired more than 500 mines, and in the Dolomites Italians and Austrians blew up mountain tops, such as Col di Lana in April 1916. From the second half of 1917 mines lost their importance, and the tunnellers mostly built dugouts.