Siege of Vraks - Battles in the Silent Darkness: The tunneller had many natural enemies, foremost being the danger of collapse. This was mitigated by Vraks’ highly stable tectonics, with very little seismic activity affecting tunnelling (one of the reasons it had originally been selected for subterranean arms storage in the first place). But any tunnel roof will eventually collapse under its own weight and required supporting. A second danger was flooding, although pre-planning usually meant that areas with underground streams and rivers were detected and avoided, pumps (often operated by hand) were installed to remove the excess seepage. Still it was not unusual for miners to work ankle deep in water. A third danger was the build-up of gases. Working in a low oxygen environment meant that odourless gases were an ever-present threat. Engineers were protected with small gas detection devices and were equipped with respirator masks with an oxygen supply.The miner’s one other great natural enemy was noise. Below ground the only way to detect the presence of an enemy was by sound. Sound travels very well through rock and an enemy could be quickly located by listening for the sounds generated by his work. Picks clashing with rocks made noise, as did digging with spades or the tramp of boots. In the darkness of a deep gallery any noise could give away a position and expose a tunnel to counter-mining and destruction by a secretly placed collapsing charge. The tunnelling war was one of stealth, with noise kept to a minimum at all times.When enemy tunnels could be detected they could be destroyed by counter-mining. A counter-mine team would seek to intercept the approaching enemy tunnel and set an explosive collapsing charge to destroy it. Collapsing charges, also known as torpedo charges or mole launchers due to their distinctive shape, were used to create a directional blast that would collapse the enemy tunnel. Krieg engineers carried such specialised equipment, whilst the enemy could fabricate their own using blasting charges. A charge would be set by boring it into the side of the tunnel, blocking off the gallery with a wall of sandbags (to contain the explosion) and running a detonator cable back to a safe distance, usually the surface. The charge’s explosion would detonate in an avalanche of earth and rock that would bury the occupants of the tunnel alive, or trap them inside an unmovable wall of earth and rock. By the time a rescue party could dig through the wreckage, the trapped miners would be long dead due to oxygen starvation, a slow and lingering death. If the enemy had detected a tunnel and not been detected in turn, mole launcher attacks came without any warning. Just as on the surface where sudden death could come at any moment from a stray artillery shell, so the engineers endured a war where death struck mercilessly and unheralded.Alternatively, a counter-mine team might seek to break in and capture an enemy’s tunnels. In the event that the enemy broke through, then invariably a vicious close quarters fight would ensue. In a darkness illuminated by wildly waving torch beams, with shotguns, pistols, grenades and knives, the two sides would struggle for control of the tunnel. In such a confined space, fights would always be brutal and short.During mining operations against a bunker in sector 544-469 by the 188th engineer company, an excavation team detected an enemy counter-mine and carefully dug under it, patiently waiting for a chance to break-in and investigate the enemy workings. The company set a collapsing charge behind themselves, as insurance should the enemy break through into their gallery, so it could be quickly sealed. All work ceased as they listened night and day until no enemy digging could be heard. Predicting that no enemy were present Lieutenant Zoltz led a hand-picked squad to the end of his tunnel and ordered them to break through. Working quickly with mattocks and picks they soon opened a hole into the enemy tunnel floor. All was silent and dark beyond. Lieutenant Zoltz was first through, scrambling up, his flashlight showing the way. Squatting in the low tunnel he directed half his squad to the left, whilst he led the second half to the right.Creeping forwards, Zoltz was approaching the enemy frontline when he came to a fork in the tunnel. Turning off all torches he listened hard. There was the unmistakable sound of approaching boots from the right fork. He ordered his men up the left fork and they waited for the enemy to pass by, hoping they were returning to the tunnel face. Through his monocle eye-piece he counted as six enemy miners, tools in hand, pistols holstered, passed them and scurried off into the darkness, from the direction he had just approached. Zoltz was faced with a dilemma, he might be able to find an access to an enemy trench or bunker, but half his squad would be surprised by the arrival of the enemy that had just passed him. Zoltz determined his plan. He put two men at the junction as guards and to set a demolition charge and destroy the tunnel junction. He would stealthily follow the enemy miners and ambush them before they encountered the second half of his squad.Moving stealthily, the remaining three men at his back, laspistol levelled, Zoltz approached the rear of the enemy digging team. Suddenly the tunnel was illuminated by approaching flashlight beams. The second half of the squad was returning from the tunnel face, unaware that the enemy was directly ahead of them. Zoltz fired, hitting the rear man in the lower back and he collapsed to the floor with a scream of pain. Suddenly there was total confusion and firing in all directions. The enemy miners were trapped between the approaching squad and those behind but put up a brave fight with their autopistols. The tunnel was alive with ricochetting bullets, sudden muzzle flashes and the bark of shotguns. Smoke filled the narrow tunnel as one by one the enemy were cut down. A grenade exploded, sending a powerful blast wave racing down the tunnel and knocking Zoltz and his men to the ground, dazed and winded. In the confusion Zoltz had also been shot in the arm and could feel his tunic becoming damp and sticky with blood. He flipped his flashlight back on and shouted a warning to his approaching men that there were friendly troops here. The shooting stopped. All the enemy were down, riddled with shotgun blasts. Three of Zoltz’s engineers had been injured. These men he ordered back through the hole into their own tunnel. The others should come with him, back to the fork where the demolition charge was almost ready.The sudden firefight below ground had not gone unnoticed and more enemy were on their way to investigate. This time they were ready for action. At the fork they encountered the demolition team. As Zoltz approached again he heard the echoing blast of shotguns. Running as fast as he could in the low tunnel, he saw his two men emptying their weapons along both forks. Another grenade exploded, its trapped force sent a second shock wave through his squad and filled the tunnel with blinding grey smoke. Both the engineer defenders had been caught in the blast and killed. Through the cloud Zoltz could see more approaching torch beams. There was no time to fire the demoliton charge, it was time to fall back. Zoltz ordered that he would hold the enemy here, the others should get back to their own tunnel and prepare to seal it against an enemy intrusion. Taking one of his men’s shotguns and spare ammunition he began firing down the tunnel whilst his men retreated, leaving their officer to his lone defence. The blast of shotgun shells kept the enemy at bay as he worked his way back to the entrance hole and jumped down. The enemy were close behind in the darkness, firing blind after him, bullets whined and buzzed around Zoltz as he made his escape. One buried itself in his rigid breastplate, shattering his torch.The engineer-lieutenant staggered back to the demolition charge detonator, where the five survivors of his short but bloody expedition awaited his return. Still bleeding and starting to lose consciousness, he waited for the enemy to close in, then ordered the charge to be fired. The explosion collapsed the roof of the tunnel in a landslide of rock, crushing the advancing enemy and sealing the tunnel. During the skirmish, Zoltz had lost two men and a further four had been wounded, including himself. His expedition had killed at least six, and maybe more, enemy miners. Other mole mortar shells could now be fired to destroy the enemy workings entirely.The enemy responded to such incursions below their positions and into their tunnels by using booby traps and leaving more guards in the tunnels.