30 m below the surface of a field in West Flanders, in a shaft 4t wide and 5t high, a man from the coal seams of Walls End is working a clay face with a grafting tool. He cannot stand upright. He has not stood upright in this shaft for 11 hours. The air is warm and wet and carries the smell of the candle 3 meters behind him and the sharpest smell of the earth he is cutting into which is blue gray epian clay dense enough to hold a tunnel without shoring but wet enough to coat every surface and every man in a film that does not dry. He can

hear his own breathing. He can hear the man behind him breathing. And somewhere to the northeast at a distance he estimates at 40 m but cannot verify. He can hear digging. The Germans are tunneling, too. The sound is small, smaller than the sound of a watch being wound. It comes through the clay in a way that makes the clay itself seem to be listening.

 The man lowers the grafting tool and sets it against a sandbag nolessly. He wraps his hand around the edge of the blade so that no metal touches any other metal. He lays the palm of his other hand flat against the tunnel wall, and he does not move. Behind him, the candle flickers once as someone breathes too hard.

 Further back, at the junction where the heading meets the main gallery. A listener sits on an ammunition box with a geophone pressed against the clay and stethoscope leads running into his ears. He writes nothing down. Writing makes noise. He keeps what he hears in his head. And if he hears the tapping change pitch, which is how you know a German pick has moved from clay into chalk, from a lateral drive into a shaft sinking downwards, which is how you know they have found you.

 He taps the man nearest him twice on the knee, and the whole heading empties in the dark soundlessly, 30 m down, 4 ft wide, 5 ft high, because there is no other way to do it. You do not light new candles here. Candles are small and the air is small. And each flame burns the same air the men are trying to breathe.

You do not speak above a breath. You do not drop a tool. You do not cough. If a man has to cough, he presses his face into the cloth of his own sleeve and bites through the cough until his eyes water. If a man has to piss, he does it where he stands quietly and the piss soaks into the clay the way everything soaks into the clay.

 You wear rubber sold boots or you wrap your boots in sandbag cloth. You pass the excavated clay backwards in sandbags down a line of hands and the hands do not drop the bags and the bags do not knock against the timber and the timber does not creek because the timber has been cut and jointed so it will not creek. You work 8our shifts because no one can stand this for more than 8 hours.

 And when you come out of the shaft you do not speak for some time because coming back into speech after 8 hours of not speaking is a thing that takes a minute. Imagine the silence in which work is happening. Imagine what it costs. Picture a man with a pick in his hand in a tunnel no wider than a wardrobe with 300 ft of wet clay above him.

 And he is cutting a hole through which he and the men behind him will eventually push an explosive charge larger than any explosive charge placed beneath the surface of the earth by any human being before them. and he has to do it without making enough noise to be heard by another man doing the same thing from the other side at a distance he estimates at 40 m but cannot verify.

The word for that kind of work does not exist in any of the civilian trades these men came out of. They had to invent it down here as they went. The man from Walls End has a son who is also down here. He is 17 shafts up the gallery working a different heading. They see each other at shift change at the entrance to the deep dugout where the rest of the company sleeps. They nod.

 They do not embrace. Embracing is for other places. The father goes in and the son comes out and the son sleeps. And sometimes when the son is asleep, the father thinks about the weight of the clay above them both. And he does not think about it for long. Because thinking about it is a habit that ends badly down here 30 m below the surface of a field.

 in West Fllanders in the last winter of the war that will outlive most of the men in this gallery. The gallery has a name. The name is Berlin Tunnel. The hill it runs towards on a map held by officers a kilometer behind the front is called Hill 60. It is 60 ft high, not 60 m. It was not a hill at all until a railway cutting was dug through this land in the 19th century and the spoil was piled on either side.

 And by 1915, the Germans held it. And by 1916, the British had decided that what could not be taken from above would be taken from below. And by November of 1916, when the Australians arrived to relieve the third Canadian tunneling company, and to take over the maintenance of the two completed mines already charged and waiting, the operation had been running for 18 months and had killed more men than anyone had yet had the leisure to count.

 Now, the Australians are the ones down here. And the two mines, one of them charged with £53,000 of ammonal and the other with £70,000, are waiting. And the Germans are tunneling, too. The men who came to this shaft did not come from the army. They came from Broken Hill, where they had learned what a rock sounds like before it falls.

 They came from Calgi where the cold was deep and the heat at face was sometimes 50°. And a man who could not listen to the ground was a man who did not come home at the end of a shift. They came from Bendigo where the old quartz reefs ran hundreds of meters down and the shafts were timbered by men whose fathers had timbered them before them.

 They came from Walls End and from Cessnok out of the Hunter coal fields where fathers and sons worked the same seam and a pit disaster on a Tuesday was a funeral for 12 families on a Friday. They came because the British army by the winter of 1915 had realized that the war was going to be decided by men who could work underground and there were not enough such men in the British Isles to do what needed doing.

 And the Dominions were asked, and the Dominions sent what they had, which was a company of miners who between them had spent something in the order of a quarter of a million manshifts below ground before any of them had ever worn a uniform. The recruitment was quiet. It was not the kind of recruitment that came with posters and brass bands.

 A man at the Broken Hill Proprietary Office would come down the shaft at the end of a shift and talk to two or three of the older miners, and they would talk to others, and within a week, a name would be on a list, and within a month, the man would be on a ship. The ship would take him to Plymouth. From Plymouth, he would be taken to a training camp where he would be taught how to wear a uniform, which was easy, and how to fire a rifle, which was easier, and how to behave around officers, which he would forget the moment he went underground.

Then he would be put on another train and another ship and eventually he would find himself in a village in Flanders and the officer in command of his section would walk him to the entrance of a shaft and tell him which heading he was working and he would go down and the war would close over his head.

 These were not ordinary soldiers. They did not drill well. They did not salute with enthusiasm. Some of them were in their 40s which by the standards of the infantry made them ancient. Some of them had sons in the same company, some had brothers. The Hunter Valley contingent was threaded through with family names repeated two and three times over because the coal scenes had been worked by the same families for three generations and a tunneling company in Flanders was really just a coal pit relocated. They brought their own

language with them. They called the tunnels drives. They called the working face the face. They called the short lateral tunnel that branched off the main gallery to listen for the enemy a listening post. They called a small explosive charge laid in a counter tunnel to collapse a German gallery, a camoufl which was French and which they pronounced their own way.

 The Royal Engineers officer who had designed the geology of the whole Messian scheme was not a soldier at all in any original sense of the word. His name was Edgeworth David and he was 60 years old and he had been professor of geology at the University of Sydney and he had gone to Antarctica with Shackleton in 1908 and he had climbed Mount Arabus at the age of 50.

 And when the war came, he had put on a uniform and gone to France. And he was the man who had told the British command which seems would take a tunnel, and which would not, which clays would shore themselves, and which would flood, where the Epsian ran deep enough and dense enough to hold a shaft of the length the scheme required.

 He walked the front line with a geological hammer. He went down the shafts and put his ear to the clay and told the officers what they were hearing. He was the reason the tunnels could be where they were as long as they were at the depths they needed to be. The miners from Broken Hill and Calguri knew who he was and they called him the professor and some of them who had read the newspapers in the old days remembered that he had walked to the South Magnetic Pole with a man named Morrison and had come back alive when most of the people who tried things like

that did not. The scheme was simple to describe and almost impossible to execute. A line of mines would be driven under the German positions along the Messine White Sheet Ridge, the slight rise of ground southeast of Epra that dominated the salient and had been held by the Germans since the first months of the war.

 There would be more than 20 mine chambers in total, charged with a combined 500 tons of high explosive, principally ammonol, and gun cotton. They would be fired simultaneously in a single coordinated detonation and the infantry would then advance across the shattered German front line and take the ridge. That was the scheme.

 It had been approved in early 1916. It would not be fired until June of 1917. In the intervening 18 months, the tunneling companies of six different nations, British and Canadian and Australian, would dig and maintain and countermine and defend the galleries. And the Germans would dig back and some of the mines would be found and lost and some would be charged and then flooded and then recharged.

 And by the time the scheme was ready to be fired, 16 months of work would have gone into an operation whose whole effect was to last for approximately 20 seconds. The Australians took over Hill 60 in November 1916. The two mines there, Hill 60A beneath the hill itself and hill 60 billion beneath the caterpillar, a spoil heap on the far side of the railway cutting, had been completed and charged by the third Canadian tunneling company earlier in the year.

 The Australians were not there to dig them, but to hold them. Holding them meant 7 months of countermining. It meant sitting in the listening posts and waiting for the sound of a German pick in the next seam. It meant going out at night with small charges and placing them in lateral tunnels angled up or down or sideways towards wherever the listeners had last heard the enemy and firing them and collapsing whatever was beside them and hoping that what you had collapsed was a German gallery and not an empty seam or worse one of your own tunnels you had

lost track of on the plans. It meant the dark and the wet and the waiting month after month with the two mines charged and ready and the whole enterprise dependent on nothing being discovered, nothing being heard, nothing being betrayed. In December of 1916, the Australian listeners reported that a German working was so close that the vibration of the enemy pick could be felt through the wall of the Australian heading.

 The decision was made to fire a camoufl a ton of ammono at the end of the heading. It was fired on the 16th. The ground shook for some time afterwards, and when the listeners returned to their posts, the sound on the other side had stopped. For 3 days, nothing. Then faint further off resumed. The Germans had moved and begun again from a different angle, at a different depth.

 It was like that for the whole of the winter. You collapsed one tunnel and another came at you from a direction you had not expected. The listeners slept in shifts. The geophones were pressed to the clay around the clock. On the 25th of April 1917, a detonator exploded inside the Australian underground headquarters dugout.

 10 men were killed by an accident that no one fully reconstructed afterwards. A reminder that the mines were dangerous to the men who had charged them as well as to the men on whom they would eventually be fired. In March, the tunneling rate increased to 5 1/2 mters per day. In April, the same. In May, the same. The miners were not making new mines at this point.

 The Hill 60 mines were already charged. They were extending galleries, sinking listening posts, preparing the infantry subways that would allow the assault troops to reach the forward trench without crossing the surface. The work never stopped. The work had not stopped for 18 months. Somewhere on the ridge, below farms and fields and the remains of villages, a second set of charges was growing.

 Along the line, in 21 separate chambers, the ammonal was being stacked in waterproof tins, wired, tamped, and left. The longest gallery at Kruistat was 660 m long. The deepest chamber was more than 30 m below the surface. The total explosive load when all 21 chambers were charged, came to 450 metric tons, it was by any measure the largest deliberate accumulation of explosive power that had ever been assembled in one place for one purpose in the history of the species.

 The Germans knew something was happening. Aerial reconnaissance in April 1917 confirmed that a British offensive was being prepared in the machine sector. The German mining officer responsible for the salient, Obuslo Nant Fuseline, had recorded the previous December that he believed the British deep mines were real and were being prepared to support an infantry assault, and he had been given three additional mining companies to hunt them. His men dug.

 They found some. They did not find enough. They blew a camoufl in August of 1916 at La Petite Duv which wrecked a British gallery for 400 ft and caused one of the 21 planned mines to be abandoned. They came within meters of several others. They dug and they dug and for 18 months the question of whether they would find the mines, whether they would find them all, whether they would find the decisive ones was a question to which no one in either army knew the answer until the answer was given.

 On the evening of the 6th of June 1917, General Sir Herbert Plumemer, commanding the British Second Army, held a final conference at his headquarters at Cassell. He was a heavy set man, methodical, disliked by Heg and adored by his troops, who had been given command of the Epra sector in 1915 and had held it for 2 years.

 He was known for his preparation. He did not attack until he was ready. He had been ready for this for a long time. At the close of the conference, he stood up and made a remark to his staff, which was later repeated and which has since been repeated often enough to become one of the things people know about this battle.

 He said, “Approximately, gentlemen, we may not make history tomorrow, but we shall certainly change the geography.” A version of the same remark was made the same evening by Plumemer’s chief of staff, General Sir Charles Harrington, to a group of journalists at Army headquarters. Harington was a meticulous planner and he knew what was coming.

 And he also knew that if one in 21 of those mines failed, if one of them was found in the night and disabled, if one of them misfired, the whole scheme would unravel and the Germans would know and the infantry going over the top at dawn would go over into the standing German machine guns of a position that had not been reduced.

 He said it to the journalists in the manner of a man who believed it, but who did not yet know it. At Hill 60, the men of the first Australian tunneling company spent the evening at final checks. The two mines, Hill 60A and Hill 60B, were connected to a firing position in a dugout some distance behind the front line. Two officers, Captain Oliver Woodward, and two other tunnelers held the exploder switches.

 Woodward was a metallurgist from Tentfield, New South Wales, who had worked in North Queensland and who after the war would end up as general manager of North Broken Hill. He had thrown the switch before on smaller charges. He had never thrown a switch connected to 123,000 of Aminal. The Hill 60 mine was £53,000. The Caterpillar mine was £70,000.

Together, they were not the largest of the 21 mines. They were close to the largest. Woodward had been given the responsibility because he had been a mining man all his working life and because the officer who had held the responsibility before him had been transferred and because the commander of the first tunneling company had looked at the list of his officers and had picked the one he trusted most to stand in a dugout with a finger on an exploder switch and press it at a time written in an order in his pocket and not 1 second

before and not 1 second after. At 2:00 in the morning on the 7th of June 1917, the British artillery barrage, which had been running for days, lifted. It did not stop completely. It ebbed to a level of covering fire designed to keep the German centuries from standing up in their trenches.

 The men of nine infantry divisions, who had been assembling in the forward trenches through the night, fixed bayonets. Some of them had been told what was coming, some had not. There was an order given up and down the line to maintain absolute silence. The miners underground in the firing dugouts sat on ammunition crates with watches in their hands.

 The galleries had been evacuated. Only the firing parties remained above them. In the trenches, 60,000 men waited for an event that would either happen or not happen, depending on whether some 21 circuits, most of which had been laid months earlier and buried under clay ever since, were still electrically continuous when the switches were thrown.

 In the half hour before the mines were fired, the British artillery fell silent. In the silence, soldiers in the forward trenches later remembered a nighting gale began to sing. It sang somewhere in the ruined wood behind them, and for the minutes between the lifting of the barrage and the firing of the mines, its song was the only sound along 10 mi of front.

 At 10 minutes past 3 in the morning local time, on the 7th of June 1917, Captain Oliver Woodward in a dugout behind Hill 60 with a watch in one hand and an exploder switch in the other counted down. Light, a column of it, white from the ground at his feet to a height no one afterwards could measure.

 Then another, then another, running along the line of the ridge, north to south, at intervals like a row of candles being blown inwards. Sound, not one. 20 seconds of it. The ground went first, then the air. The watch in Woodward’s hand flew out of his hand. Gone. Most of hill 60, most of the Caterpillar, most of Spanuk Molen, most of Kruat, most of Peekom, most of the German front line for 10 mi.

 The earth rose. The earth stood up. The earth stood up 200 ft high and hung in the sky for a moment and came back down. Men in the British trenches saw pillars of fire. They said so afterwards, and the words were the same from man to man along the line. Pillars of fire. A soldier named May, a machine gun officer, said he heard a deep rumble and turned to shout an order.

 and the order was taken out of his mouth by a shock wave he did not hear because his ears had already shut down. The ridge gone. The men who had been standing on the ridge gone. A whole company of Wartenberers posted on hill 60 that morning. According to the Germans who afterwards tried to account for them gone.

 In London, Prime Minister Lloyd George heard it. He was in Downing Street. He heard a door slam that was not a door. In Dublin, people heard it. Houses in Dublin, doors rattled. At Le University in the geology department, the seismograph recorded what the duty staff took for an earthquake. 10,000. That is the figure, 10,000 men. At the lowest estimate, killed in the 20 seconds it took the mines to fire.

 Some killed by the blast, some killed by the earth falling on them, some killed by nothing that could afterwards be reconstructed. whole dugouts of men 70 or 80 ft underground found later with no marks on the bodies. The air had gone out of their lungs and taken everything else with it. The men in the forward British trenches saw the ridge rise and did not move.

 Then they went over the top. They walked. Most accounts say they walked. The German front line was no longer there. The wire was gone. The machine guns were gone. The men who had been standing at the machine guns were gone. The Germans in the support trenches were stunned beyond movement. The British and Australian and New Zealand infantry went forward and took the ridge and held it.

 And by nightfall, the objective had been secured. At hill 60, behind the firing dugout, Woodward was on his feet. He was not sure how he had got there. The air in the dugout was white with dust. He was shouting and could not hear himself shouting. He found the watch on the floor. The crystal was broken. He put the watch in his pocket.

 He walked to the mouth of the shaft. The shaft was full of light. No, the shaft was gone. What had been the shaft, the gallery they had maintained through 8 months of Fllanders’s winter and spring, was a crater. The crater was 80 m wide. The crater was already filling it. At the bottom of the crater, tangled in the broken clay, were things that had been German soldiers.

 They were not recognizable. The British official photographer who came forward later that morning took pictures. The pictures were not published in the newspapers of the time. The Australian sappers in the rear gallery came up. They came up covered in dust. They came up deaf. They came up in ones and twos.

 The father from Wall’s End came up. The son came up. They saw each other. They did not speak. There was nothing to say. And also they could not hear. By 7:00 in the morning, the crater had begun to take water at the bottom. By noon, it was half full. It would fill entirely in the following weeks. It is still there. Afterwards, there was a silence.

 It was the second silence of the day. It was the silence of the whole sector of the front, the silence of men in trenches and men in craters and men in dugouts who had been deaf for 2 hours and were slowly coming back into sound. It was the silence of the landscape itself, which had stopped looking like a landscape and had begun looking like something the earth had briefly swallowed and then spat back up different with its features rearranged.

A ridge that had been a ridge on the morning of the 6th of June, and was by the evening of the 7th a series of connected craters separated by strips of churned ground. Nine divisions of infantry advanced behind a creeping barrage. They took meines, they took witchy, they took the whole of the ridge within hours.

 7,000 German prisoners were taken by the end of the first day. German counterattacks on the 8th of June failed and failed again on the 9th and failed again on the 10th. By the 14th of June, the Messine Salient was in Allied hands. The cost to the British second army was 17,000 casualties over the 7 days of the operation against German casualties of 25,000 which made me the first operation of the war on the western front in which the attackers losses were lower than the defenders.

 It was called a victory. Plumemer was praised. Harrington was praised. The official history when it came to be written gave the tunnelers a chapter and named some of them and recorded that the first Australian tunneling company at Hill 60 had held the mines through 7 months of underground warfare of an intensity unsurpassed anywhere on the British front.

 About 30 Australian tunnelers had been killed at Hill 60 in the course of that holding. Their names are on a memorial at the site. The memorial was erected in 1919 by their comrades in a modest form and replaced in 1923 with the current brass plaque which was afterwards struck by bullets during the German occupation of 1940 to 1944 and the bullet holes are still there and the plaque has not been repaired because the bullet holes are now also a part of the monument.

 Oliver Woodward came home. He married a young woman named Marjgerie Wadell whom he had been courting before the war in 1920. He went back into civilian mining. He rose through the ranks of the North Broken Hill Company, the same Broken Hill that had supplied a great many of the men who had worked under him and by 1935 he was the general manager.

 He became president of the Australasian Institute of Mining and Metallergy in 1940. He died in 1966 aged 80. He kept a diary through the war written in the dugouts at Hill 60 and at Armentiier and at Huj. The diary survived in the possession of his family. 70 years after the mines were fired, a film was made from it. Of the 21 mines charged for Messine, 19 fired on the 7th of June 1917.

Two did not. One, a charge of £20,000 at a position called Peekom, had been abandoned before the battle because the tunnel had collapsed. The other, one of the largest mines of the whole scheme, had been laid beneath a ruined farm called Leatit Duv. It had been charged in 1915 and damaged by a German camoufl in August 1916 and left in place.

 Its exact position was known to the British engineers of 1917. The records, however, were mislaid in the long aftermath of the war. And by 1930, no one in Belgium or Britain could say precisely where the charge lay. It was still there, under a farm, under a field, under a country that through the 1920s and 1940s went about the business of rebuilding itself as if the thing below the ground had not been left below the ground.

 On the 17th of June 1955, during a thunderstorm in the Messen’s district, a lightning strike somehow completed a circuit that had been buried and forgotten for 38 years, and one of the two remaining mines fired. It blew a crater in a field. It killed a cow. It did no other harm. The Belgian authorities afterwards investigated and confirmed that the lost mine at the position called Trench 127 had been detonated by the storm.

 The other mine is still there. It is still charged. The detonating caps have presumably decayed. The ammonal, if it has stayed dry, is presumably still capable of firing. The position is approximately known. The land above it is farmed. No one has attempted to recover it. The Belgian authorities have taken the view that the charge is more safely left where it is than dug up.

 And the farmers have taken the view that what one does not disturb does not disturb one back. and the ground does not disturb itself. The shaft at Hill 60 is still there. The entrance is sealed. The tunnel descends into clay that has not been disturbed since June of 1917. No one has gone down. No one will. Somewhere in the darkness, 30 m below a field where Belgian cattle graze and tourists photograph the memorial, the tools the Australians left behind, are resting where they were set down on the night the men climbed out for the last

time, walked to the surface and waited for the earth to open. The cattle are still there. The grass is still there. The crater on the northern lip of the hill is still full of water. It is now a pond. Frogs live in it. A low iron fence keeps sightseers from slipping down the sides.

 The caterpillar crater a few hundred meters away has become a larger pond and the trees around it have matured into a small wood. If you walked the ridge at dawn, you would see mist rising from the ponds and you would see cattle standing in the grass between them and you would see the memorial and you would hear probably nothing at all except perhaps a bird in the wood.

 and perhaps a distant tractor on one of the farms that begins in summer a little before the mist clears you. You would not know from the look of it that 10,000 men were killed here in 20 seconds in the summer of 1917. You would not know that 500 tons of explosive were tamped into chambers beneath your feet by miners from Broken Hill and Calguli and Walls End.

 You would not know that some of those miners are in a sense still down there in the galleries that were sealed and never reopened and that the tools they left behind on the night of the 6th of June have been resting in the dark for over a century. You would hear the wind in the grass. You would hear the cattle moving.

 You would hear at the very edge of hearing a sound that would not quite resolve into a sound and you would go home and you would not think about it again for some time until one day perhaps in a city a long way from Fllanders you would hear a door slam somewhere that was not a door and the sound would remind you of something and you would not be able to say what below the field the second mine is still waiting.

 The clay around it has not moved. The wire that connects it to the detonator, if any of the wire remains, runs underground that has been plowed and not plowed and plowed again. Somewhere a circuit remains incomplete. Somewhere a charge remains charged. The war that the men of the first Australian tunneling company were asked to fight has been over for more than a hundred years.

 And the mine they laid under a farm has been sleeping under the farm for all of that time. And it will sleep for as long as the ground above it is not disturbed. And when at last it is disturbed by lightning or by a farmer’s plow or by nothing in particular by a weakness in the clay that gives way on its own as clay eventually does.

 It will do what it was made to do. It will take a long breath. It will lift the earth above it into the air. It will kill perhaps a cow or perhaps nothing. Perhaps it will not fire. Perhaps the caps are dead and the ammonal is wet and the whole thing has quietly over the decades become inert. A fossil charge, a memory in explosive form, a thing that was once a weapon and is now only a shape in the clay. No one knows.

 The miners who laid it are dead. The officers who commanded them are dead. The soldiers they were meant to kill have been dead for a century. The ridge stands where they put it, slightly lower than it stood in 1914, missing the crest that was blown off at 10 minutes 3 in the morning of the 7th of June 1917. Cattle graze. Ponds hold their water.

The memorial with its bullet holes holds its brass plaque. The names of the dead are on the plaque. The names of the living are in other places. And somewhere under the field in the clay that Edgeworth David once mapped for the tunnelers. The last charge is waiting or not as it will.

 The man from Wall’s End went home. His son went home with him. The father went back to the coal. The son went back to the coal. They worked the scene they had been working before the war. and they did not speak either of them of the 18 months they had spent underground in Fllanders, except sometimes on an evening when a blasting charge was fired at the face and the ground gave its small familiar cough and then the father would put his hand on the wall of the drive flat, palm down, the way he had put it in the dark at Hill 60 and he would hold it there for a

moment and he would not say anything and he would take his hand away and he would go back to