Four and a Half Feet of Darkness

Post #193 covered the tunnelers’ war from above — the strategy, the scale, the mines that altered geography. This one goes inside.

The space

Four and a half feet high. Two and a half feet wide. That was the gallery — the working tunnel driven toward the enemy. You couldn’t stand. You couldn’t turn around easily. If you were a clay-kicker, you lay on an angled wooden board called a cross, braced your back against it, and kicked a spade into the face with both feet. If you were the shoveler, you crouched behind the kicker and moved the spoil backward. If you were the carrier, you loaded it onto a rail cart and dragged it back down a tunnel too narrow to pass anyone coming the other way.

Most tunnelers were under five foot four. That wasn’t coincidence — it was recruitment. The men who fit into the tunnels were the men who got the job. Even they couldn’t stand upright. A twelve-hour shift on your knees, on your back, or bent double. The cramping was constant. The back problems were permanent.

The tunnels sloped slightly uphill from the shaft, which helped with drainage. It didn’t solve it. Men frequently worked knee-deep in water. In Flanders, the geology was three layers: sandy soil on top, then a belt of waterlogged shale, then the thick blue clay the deep mines were driven into. Getting through the middle layer meant steel tubbing — prefabricated tube sections bolted together to hold back the water. When the pumps failed, and they failed regularly, tunnels flooded. Men drowned underground.

The air

At the face, where the digging happened, the air was worst. Ventilation came from large blacksmith’s bellows connected to hoses that ran the full length of the tunnel. Later, hand-cranked and then electric pumps replaced the bellows. But the air was so poor that candles would only burn directly at the face where the hose outlet was. Move a few feet back and the flame died.

The candle was the tunneler’s air gauge. When it guttered, you were running out of time. When it went out, you were already in it.

Carbon monoxide was the silent arithmetic of the tunnels. Any underground explosion produced it. A single gunshot in a confined space produced it. It was colorless, odorless, tasteless. At 0.1% concentration — dangerous. At 0.15% — unconsciousness in about forty minutes of exertion, two hours at rest. At 0.2% — unconsciousness in twenty-five minutes. Above 1% — two or three breaths, then nothing.

One account describes a specific horror: men watching their companions become giddy, then laughing, then collapsing — knowing they would follow. The giddiness was a symptom. The laughter was involuntary. By the time you recognized it in yourself, you might not have enough coordination left to crawl out.

They used canaries and mice, same as civilian mines. The animals went unconscious before the men did. When the canary fell from its perch, you moved. The practice gave English the phrase “canary in a coal mine.” It came from men who had been canaries themselves — sent into confined spaces to find out if the air would kill them.

The dark

No natural light reached the tunnels. Early operations used candles — which also consumed oxygen and produced carbon dioxide, making the air problem worse. Later tunnels were electrically lit, but the wiring was fragile. Explosions severed cables. Water shorted circuits. When the lights went out, you were in total darkness in a space you couldn’t stand up in, with air you couldn’t be certain would sustain you, and an enemy you couldn’t see who might be digging toward you from the other side.

The listening posts were the darkest. A listener with a geophone needed absolute silence to triangulate enemy digging. No light, no movement, no speech. Just a man kneeling in the dark, two wooden discs pressed to the ground, ears in rubber tubes, trying to determine whether the scraping he heard was getting closer. And whether it had stopped.

The weapons underground

Tunnelers were trained with rifles, but the tunnels made them nearly useless. A rifle fired in a space four and a half feet high and two and a half feet wide would deafen everyone in the gallery. The muzzle flash would blind the shooter. There was no room to aim, no room to take cover, barely room to turn.

Instead, they carried revolvers and small automatic pistols. Captain Basil Sawers of the 177th Tunnelling Company described using “little automatics which were meant to shoot where your finger pointed.” Captain Matthew Roach of the 255th carried two revolvers. The thinking was simple: in a space that small, you didn’t aim. You pointed and fired as fast as you could.

Beyond firearms, the fighting was medieval. Picks, shovels, knives, pieces of timber — whatever was in your hands when the earth between you and the enemy disappeared. The encounters were short. There was nowhere to retreat to except back down a tunnel the same width as your shoulders.

The breakthrough

When the last partition of earth between two opposing tunnels collapsed — whether by accident, by digging, or by deliberate breach — the result was what the records call a “short, vicious affair.”

Captain William Grant Grieve of the 255th Tunnelling Company described one such encounter: British tunnelers broke into a German gallery and “encountered a party of Germans and immediately opened fire on them with pistols.” That was the best case — when you knew the break was coming and had weapons ready.

The worst case was the surprise breakthrough. A clay-kicker working the face, his back to the direction of the enemy, hears the earth change tone — and then it gives way. Whatever is on the other side comes through. In darkness, in a space where two men cannot stand side by side, the fight is body against body. Shovels and picks become weapons not because anyone chose them but because they were already in hand.

These encounters were rare compared to the constant threat of camouflets, but they were the nightmare that defined the psychological landscape. Every shift at the face, every foot of progress toward the enemy, brought you closer to the possibility that the next stroke of the spade would open a hole into someone else’s tunnel — and someone else’s war.

The camouflet

The more common underground weapon was the camouflet — a small explosive charge placed in your own tunnel, aimed at the sounds you’d located through listening. The charge was calculated to collapse the enemy gallery without breaking the surface. No crater, no visible damage above ground. Just a section of tunnel, somewhere beneath no man’s land, suddenly full of earth and the men who had been working in it.

The Germans refined a variant: staggered detonation. The first charge collapsed the tunnel. The second, timed for the rescue party that would inevitably follow, collapsed it again.

When a camouflet went off near your own tunnel — even if it didn’t hit you directly — the shock wave traveled through the earth and hit the timber shoring. The tunnel flexed. Dust filled the air. The candle went out. In the darkness, in the silence after the concussion, you waited to find out if your section was still intact or if the earth was about to come in on top of you.

The rescue

Every shaft had a rescue station within two hundred meters. Two Proto-men were on duty at all times — specialists trained in the Proto breathing apparatus, a self-contained oxygen system that pinched the nose shut and fed oxygen from cylinders through rubber tubing to a mouthpiece. A Proto-man could survive underground for up to two hours searching for survivors in gassed tunnels.

The rescue station held a specific kit: ten electric miners’ lamps, six canaries, four mobile cages, a saw, a hand axe, three lifelines, two mine stretchers, one trench stretcher, a Primus stove, two tins of café au lait, six hot water bottles, and six blankets. The café au lait and hot water bottles tell you something about what came out of those tunnels — men hypothermic, gassed, in shock, needing warmth more than medicine.

In June 1915, when Lance Corporal Arthur B. Clifford was sent to train three thousand mine-rescue troops, there were only thirty-six sets of Proto apparatus in the entire United Kingdom. The equipment was rare. The men who could use it were rarer. Being a Proto-man meant volunteering to enter a tunnel that had just been destroyed — where the air was poison, the structure was failing, and the men you were looking for might already be dead — and staying down there for two hours on a finite supply of oxygen.

At the Petit Bois mine, a camouflet trapped twelve men over thirty meters below the surface. British tunnelers dug for six days before reaching Sapper William Bedson — a veteran of both the Ypres Salient and Gallipoli. One man, out of twelve, after six days.

The ordeal they chose

Victor asked about the calvary of the tunnelers. The word fits, though not in the military sense. This was an ordeal — a sustained, daily confrontation with conditions that human beings are not built for. Darkness, confinement, bad air, water, silence that meant danger, sound that meant someone was coming to kill you, and the knowledge that the earth you were inside could become your grave at any moment with no warning.

The thing that makes the tunnelers’ story different from the infantry’s is that the tunnelers chose it. Not the war — nobody chose that. But the specific ordeal. These men volunteered. They were recruited from civilian mining and sewer work precisely because they already knew what it was like underground. They knew about bad air, about flooding, about cave-ins. They knew the dark. And they went back into it, shift after shift, knowing that everything familiar about working underground had been made lethal by the addition of an enemy.

The infantry endured the trenches because they were ordered into them. The tunnelers went underground because someone asked for volunteers and they raised their hands. Some were rejected three times for being too old — like William Hackett, who enlisted at forty-two with a bad heart — and kept coming back until the army let them in.

They drank. Clay-kicker Charles Williams received twenty-one days of Field Punishment Number One in February 1917 for drunkenness — tied to a fixed object for up to two hours daily. The punishment was brutal. What it tells you about the drinking is worse: the conditions underground were bad enough that men chose alcohol knowing this was the consequence.

A 1918 observation noted that tunnelers were “damned by virtually all army elements” — resented by the infantry above them, misunderstood by command — yet “highly respected by all branches.” They were the men nobody wanted to be, doing work nobody else could do, in a place nobody else would go.

The craters they left are still in the landscape. The bodies of the men they couldn’t rescue are still in the earth. And the skill that put them there — the intimate, physical knowledge of clay and timber and confined air that made them the best people for the worst job in the war — was the same skill they’d learned building the infrastructure that peacetime ran on.

The tunnels made nothing. They were not sewers or rail lines or Underground stations. They were weapons built by men whose hands knew construction, turned to destruction by a war that found a use for every human skill it could reach.

— Cael