Sapping and Mining in the First World War

Monday, May 10, 1915

In billets, Bailleul (Le Nouveau Monde)

The Battalion War Diarist wrote for this day: “Refitting and reorganization of battalion rapidly proceeding”. [1]

10 May 15THIS DAY IN RMR HISTORY: “To an extent which finds no parallel in history, the present conflict in France and Belgium is a sappers and miners’ war; but of the vast number of people who read the despatches from the front it is probably only a small proportion who understand exactly what these terms mean. They are often, indeed, thought to be synonymous, but there is, as a matter of fact, a material difference between the two phases of work.

Under the conditions of the war in the west, sapping and mining are practically the only methods by which an advance can be made, especially where the enemy’s trenches, though so near, are yet a trifle too far off for a bayonet charge to be successful.

Sapping is usually resorted to where the enemy’s trench is to be taken, and is slow and tedious work, very often performed under the worst of conditions. The idea is to dig a passageway to the enemy’s trench without letting him know you are coming, and to do this in such a way as to make it possible to rush the trench and expel the enemy from it.

SLOW BUT SURE: The ‘sap’ is usually dug the same depth as the trench, care being taken to go with the rise or fall of the land, and is seldom more than eighteen inches wide. At the bottom earth is dug out, the top falls in, and the earth is carried away on a ‘cradle’ and deposited at the rear of the trench or other suitable place. The course taken may be straight or zig-zag, whichever is best under the circumstances.

The reason why the bottom earth is dug away and the top left to fall in is that this method gives less chance of the pick rising above the level of the ground and betraying the work to the enemy. By this method of advance, which is slow but sure, extremely successful results are often attained.

Mining is resorted to in the course of a siege, or the blowing up of trenches, or in the making of a trench nearer to the enemy’s lines which the infantry can rush into and occupy preparatory to making a final charge with the bayonet.

UNDER THE SURFACE: In such a case, tunnels are driven about twelve feet or more below the surface, and are generally about four and a half feet high and three feet wide. These tunnels are bored at intervals along the line of the trench and carried as far as may be deemed necessary. When the distance tunnelled is sufficient, explosive charges are laid and a series of holes blown in the ground, which the infantry rush forward and occupy and connect up into a long trench. This process is continued until an approach is made near enough to the enemies’ lines for a charge.

In the case of a siege, and where counter-tunneling is known to be in progress, the system of tunnels is much more elaborate. Listening galleries are dug out, with just sufficient room for a man to crawl along and at the end of these galleries sit trained listeners, who can tell by the noise made by the enemy’s digging how far they are away and from which direction they are advancing.

Thus it will be seen that while a ‘sap’ is a sort of narrow trench dug along towards the enemy’s trench, the object being to take it by a rush, mining is a system of tunnelling under the earth whereby explosives can be used with advantage against the enemy.” [3]

[1]   War Diary, 14th Canadian Battalion, The Royal Montreal Regiment, May 10, 1915.  Library and Archives Canada, Ottawa,
[2]  “Sapping and Mining in War,” The Citizen, Ottawa Ontario, Thursday, April 15, 1915, pg. 6, col. 3.
[3]   Ibid.

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