Mines in the Battle of Messines (1917)

The mines in the Battle of Messines comprised a series of underground explosive charges, secretly planted by British tunnelling units beneath the German 4th Army lines near the village of Mesen (Messines in French, historically used in English) in Belgian West Flanders during the First World War. The mines were detonated at the start of the Battle of Messines (7–14 June 1917), creating 19 large craters. The joint explosion of the mines at Messines ranks among the largest non-nuclear explosions of all time. The evening before the attack, General Sir Charles Harington, Chief of Staff of the Second Army (General Sir Herbert Plumer), remarked to the press, "Gentlemen, we may not make history tomorrow, but we shall certainly change the geography". The Battle of Messines marked the zenith of mine warfare. On 10 August 1917, the Royal Engineers fired the last British deep mine of the war, at Givenchy-en-Gohelle near Arras.

As part of allied operations in the Ypres Salient, British mining against the German-held salient at Wijtschate near Messines had begun in spring 1915, with diggings 4.6–6.1 metres (15–20 ft) below the surface. The concept of a deep mining offensive was devised in September 1915 by the Engineer-in-Chief of the BEF, Brigadier George Fowke, who proposed to drive galleries 18–27 metres (60–90 ft) underground. Fowke had been inspired by the thinking of Major John Norton-Griffiths, a civil engineer, who had helped form the first tunnelling companies and introduced the quiet clay kicking technique.

...
Wikipedia