Fighting the Boche Underground

7–14 June 1917

Battle of Messines (1917)

CHAPTER I

The battle of Messines Ridge in July, 1916, was started by firing at the "Zero" hour some 19 mines, spread over a front of several kilometres. In these 19 mines the aggregate of the total high explosive used and fired at the same instant was a few thousand short of 1,000,000 pounds. Some of the individual charges were nearly 100,000 pounds each, and had been laid ready for firing for over twelve months. Some idea of the frightful force and power of these charges may be obtained when it is remembered that each of the "Mills" bombs, or hand-grenades carried by British soldiers, contains one quarter of 1 pound, or 4 ounces, only of this explosive. As a result of this terrific blow the Germans retreated for over a half-mile on the entire front mined, and the initial objectives of the British were captured with astonishingly low casualties.

CHAPTER III

Handicapped as were the British and French from this cause, they have succeeded by energetic and daring work since that time in more than outmatching the enemy below ground, until now mining beneath the trenches no longer consists, as it did then, in almost exclusively defensive operations. Of its use as an offensive measure, the launching of the attack in the battle of Messines last year serves as an excellent illustration.

CHAPTER VI

The charges we used in our deep mines in the chalk were tremendous, mine-chambers being loaded with anything from 1 up to 50 tons of a high explosive twice as strong as dynamite. Last year in the battle of Messines the British launched their first big attack by firing a large number of mines below the enemy trenches, using charges of from 15 to 50 tons in each mine and exploding them all at the same moment, the "zero" minute, or exact time at which the infantry go over the top. Very close to a million pounds of a remarkably high explosive were fired at the same instant by the engineers on this front. In starting an infantry attack the mining officers, in common with all the officers of the units engaged in the attack, synchronize their watches, and at the second planned, push home hard the handles of their blasting-machines. Earth-racking mines are detonated with terrific force. The craters formed from these explosions are often over 300 feet in diameter and from 50 to 150 feet deep. Whole companies of men are engulfed, all trenches within a large radius totally destroyed, and many additional men buried in their fall.

CHAPTER XIV

The mine is an irresistible means of launching an attack. In a mined sector, the best troops completely lose their bearings for several seconds after an explosion. These several seconds prevent the machine-guns from firing, and the assailant gains a foothold in the first line, and often in the second. The extent of the underground operations in launching an attack naturally depends upon the size of the offensive, whether it be a battalion, brigade, division, or army offensive. The date has been set for the general attack. Mining units, in consultation with the staff of the forces employed, will elaborate their plans for the mining operations. (The battle of Messines furnished an excellent illustration of the value and use of extensive mining in launching an attack. In these operations, the British miners fired a large number of mines from galleries under the enemy front line, and in some cases below their supports. The charges in these mines varied from 15 to 50 tons each, and were all fired at "zero" hour, the minute at which the infantry goes over the top. Nine hundred and fifty thousand pounds of ammonal were used. Some mines had been charged for fourteen months and others for a year. One charge of 95,000 pounds formed a crater 125 feet deep with 186 feet diameter. The largest crater formed was from a charge of 70,000 pounds, depth of crater 86 feet, diameter 260 feet. These mines were in chalk and clay. The result was a complete demoralization of the enemy, and the first objectives were obtained with very few casualties.) The Germans deserted their lines for half a mile to the rear. These mines were fired on a front of several kilometres. The scheme of the offensive having been planned, galleries are driven under the enemy trenches and all charges laid ready for firing.