Fighting the Boche Underground

by H. D. Trounce

As it was a rare day for us in Flanders when the enemy or ourselves did not "blow" a mine, we were always on our toes. Except in cases of sudden emergency we informed the infantry of our intention to fire a mine, and gave them the time necessary to withdraw their men to points of safety. Often we would blow a mine at night in cooperation with the infantry so that they might at once rush out and "consolidate" the crater, or the nearest lip or rim of the crater. Certain positions in No Man's Land were particularly desirable on account of their strategic value; sometimes for the purpose of enfilading the enemy's trenches by occupying one rim of the crater; or perhaps for the obtaining of better observation-points, or for any other reason. The consolidation of these craters is a wonderfully stirring business. A little explanation of a crater might help.

The engineers fire large charges of high explosives from underground galleries, at a depth of anything from 20 to 200 feet, with the result that a huge hole is blown in the ground in the shape of an inverted cone, like the average shell-hole, but very much wider and deeper. No Man's Land in front of us, where the trenches are close, is pitted with great numbers of these craters, some blown by the Germans and some by us. The craters vary from the small ones, about 70 or 80 feet in diameter and 12 to 20 feet deep, to larger ones to such dimensions as 300 feet in diameter and up to 120 or 130 feet deep. The size, of course, depends on the charge of high explosives used, the depth of the mine-galleries, and the soil one springs the mine in.

The enemy is usually just as concerned with the consolidation of the rim or lip of the crater on their side as we are with ours, and a battle royal for their occupation results. Machine-guns on both sides concentrate fire on the crater almost before the débris from the explosion have had time to fall. It is a weird and wonderful sight. From a fairly calm night, usually with only desultory fire going on, the thunderclap comes. Before firing, which is usually done electrically, the engineers calculate the exact diameter of the crater to be formed, and the previous night the infantry or engineers will have completed a trench forward from the front-line or "jumping-off" trench, to an intersection with the rim of the proposed crater. Directly the charge has been fired, they rush out through this trench and hastily throw up breastworks on the lip of the crater formed. The machine-gunners take up proper offensive and defensive positions; the bombers, usually at the head and the flank of the "throw-up," or lip, erect the wire screens necessary for their temporary protection; the "wire" men place their barbed wire around the portion to be consolidated; and all ranks dig themselves in as fast as they can, later bringing up such timber or other material as they can to strengthen the positions. When it is planned to hold the whole of the crater, the "wire" men completely encircle it with entanglements, and the Lewis gunners and bombers make such changes in disposition as are necessary. This represents the usual procedure when a crater is blown in No Man's Land. Thousands of these craters are so exploded.

On numerous other occasions, when we have penetrated below the surface with our underground galleries under and across No Man's Land to below the Germans' front-line trenches (and in many cases we go as far as their support lines without being discovered), our little affairs are accompanied by infantry raids. Pandemonium reigns supreme at these times, and nothing can be likened to the noise and apparent confusion in which these usually very successful raids are conducted. We fire our mines under their trenches and the infantry raiding-parties immediately cross and clean up any Germans we might have missed with our attentions. As a result of our noiseless work below in the clay, we would occasionally break through into each other's galleries.

Perhaps you would be interested in an underground fight which we had with the Boche in one of our galleries twenty feet below the surface under these trenches. Some two weeks before this we had successfully blown a mine, and two days later had discovered and worked through the broken German gallery we had destroyed. Passing through this gallery, we continued our silent work in the clay, and about fifty feet farther turned off to the left in order to strike what we thought would be the enemy's main defensive gallery. Our miners who were working at this face hurriedly sent up word one morning to our dugout on top, just off the shaft-house, that they had broken into the German gallery with a small hole in the clay. All men working underground had standing orders that if this occurred at any time they should at once put out their candles, observe strict silence, plug up the hole with clay, and report forthwith to the officer on duty. Warning all men to leave the near-by workings below, the officer on duty hurried down to the spot, stopped long enough in our main gallery to make up a mobile, or portable, charge of thirty pounds of guncotton from our magazine, which we had established there for just such emergencies, then proceeded with the utmost care to the gallery mentioned. Lieutenant G. had connected up a dry guncotton primer to the charge, inserted a detonator attached to a short piece of safety-fuse, which latter would burn for about two minutes before detonating the charge. The men had noticed and heard three, certainly, and probably more, Germans at work in their gallery, which was lighted with electric light. Lieutenant G., accompanied by another officer, very carefully withdrew the clay plug, enlarged the hole, slid the box containing the charge into the enemy gallery, lit the fuse, and swiftly and quietly withdrew from the scene. He reached safely the main gallery, quite a distance from the charge, in time to hear the explosion. He then climbed quickly to the top to escape the resulting fatal gases developed by the detonation of the high explosives.

I arrived on the scene a few minutes later and my section commander asked me if I was "game enough," as he described it, to go below with a sapper to investigate the damage done and see how many Germans we had accounted for. I was very willing; so Doherty, the sapper mentioned, and myself equipped ourselves with the "Proto" oxygen breathing-apparatus necessary in going into "gassy" galleries, then descended, carrying also the usual canary in a cage to test the air. The canary soon toppled off his perch and fell dead to the floor of his cage. Canaries and white mice are used in large numbers to detect the presence of poisonous gases below, and, being very susceptible to bad air, are soon killed. [It is a curious sight to see these canaries hung up outside dugouts in all trenches where mining operations are conducted.] Both Doherty and I had previously been trained in the use of the oxygen apparatus, and were quite confident of its ability to take care of the carbon monoxide so that it would not affect our lungs. Before we reached the enemy gallery, I stopped long enough to pick up and carry with me the air-hose, and this I left later in the enemy's workings so that our men on top could pump good air in and allow others down in a short time to resume the offensive. We reached the gallery, found the remains of three Boches that "G." had "sent west" with his charge of guncotton, then proceeded to investigate the damage done. As the enemy gallery was very closely timbered, we had only broken down a portion of it with the charge employed. On entering their gallery, I had carefully searched for and cut all wires that I found there. This was a regular practice with us, the object being to sever all electric leads, wires, or fuses which the enemy may have left connected to a charge or mine already laid.

Breathing-apparatus necessary in going into "gassy" galleries.

On breaking into any of these galleries the officer in charge usually enlarges the holes in the clay until he can put his arm through; feels around until he finds any wires, and promptly cuts them with his pliers. Such operations of necessity must be done in darkness and without sound, and one's heart is working like a pump-handle. I was agreeably surprised to find that no Germans had summoned courage enough to investigate matters as we were doing; Doherty, however, did not share my sentiments, and gave me the impression as best he could, enveloped in the oxygen apparatus as he was, that he distinctly regretted their lack of sand. We were both armed with electric-torches and revolvers, but we were not keen on using them oftener than necessary, and so advertising our presence. After leaving the air-hose and noting results, I picked up the cap of one of the defunct Germans, and we came out, or rather crawled out. Our progress was mostly in the form of a crawl, and the steel oxygen cylinders knocking against the timber sets in the narrow galleries as we proceeded did not improve our tempers.

We arrived safely back to the surface and I made my report. After pumping air into the gallery for about an hour, we all went below again, and my section commander and Lieutenant G. crawled through to examine conditions in the enemy's gallery, while I was engaged in the magazine in opening boxes of guncotton and getting more primers and detonators ready for action. Captain B., the section commander, came back presently and informed me that he and G. had been slightly gassed during their investigation of the enemy tunnel, but had not met any Boche; he had decided on making up some raiding-parties, would arm them with mobile charges; attempt to explore the German gallery and mine system, and, if possible, try and destroy their shaft. The difficulties of proceeding farther into the German galleries, now that the enemy was thoroughly aroused, were pretty large, but we agreed with him that it was up to us to get them somehow if we had a possible chance. We made up three of these parties at once; each composed of one officer, one non-commissioned officer, and two sappers; each party armed with revolvers and a mobile charge of thirty pounds of guncotton, the latter being carried in boxes. Each of the sappers provided himself with a couple of Mills bombs, their confidence in these useful little articles on all occasions being quite touching.