Mines on the first day of the Somme



The Mines on the first day of the Somme comprised a series of 19 mines of varying sizes, dug by tunnelling companies of the Royal Engineers under German lines on the Western Front during the First World War. The group consisted of eight large and eleven small mines which were detonated on 1 July 1916, the first day of the Battle of the Somme (1 July – 18 November 1916). The joint explosion of the mines on the first day of the Battle of the Somme ranks among the largest non-nuclear explosions. The most important of them were beneath Hawthorn Ridge Redoubt at Beaumont-Hamel, beneath a German field fortification known as Schwabenhöhe just south of La Boisselle and three in a sector named The Tambour near Fricourt. At the time, the Lochnagar and Y Sap mines were the largest mines ever detonated. The sound of the blast was considered the loudest man-made noise in history up to that point, with reports suggesting it was heard in London. The mine detonations on the Somme were not surpassed until 1917 by the mines in the Battle of Messines.

1914
French and German military operations began on the Somme in September 1914 and after attempts to resume offensive warfare in October, both sides fortified defensive lines and reduced their attacks to local operations and raids. At La Boisselle, a French attack on 17 December 1914 captured the village cemetery, which was at the west end of a German salient. The French had sapped forward for several weeks and a shortage of artillery ammunition had left the Germans unable to stop French progress. When the attack came the French were only 15 m from the German front line and then established an advanced post only 3 m away. The French attacks forced the Germans back from the cemetery and the Granathof by 24 December, against which German counter-attacks on 26 December failed.

1915
On the night of 8/9 March, a German sapper at La Boisselle inadvertently broke into French mine gallery, which was found to have been charged with explosives; a group of volunteers took 45 nerve racking minutes to dismantle the charge and cut the firing cables. From April 1915 – January 1916, 61 mines were sprung around the Granathof, some loaded with 20000 – of explosives.

The French mine workings were taken over when the British moved into the Somme front. On 24 July 1915, the 174th Tunnelling Company established its headquarters at Bray, taking over some 66 shafts at Carnoy, Fricourt, Maricourt and La Boisselle. No man's land, just south-west of La Boisselle was very narrow, at one point about 50 yd wide and had become pockmarked by many chalk craters. Elaborate precautions were taken to preserve secrecy, since no continuous front line trench ran through the area opposite the west end of La Boisselle and the British front line. The area was known to the British as the "Glory Hole" and was defended by posts near the mine shafts. The underground war continued with offensive mining to destroy the opponents' strong points and defensive mining to destroy tunnels, which were 30 – long. Around La Boisselle, the Germans dug defensive transverse tunnels about 80 ft long, parallel to the front line. On 19 November 1915, the 179th Tunnelling Company commander, Captain Henry Hance, estimated that the Germans were 15 yd away and ordered the mine chamber to be loaded with 6000 lb of explosives, which was completed by midnight on 20/21 November. At 1:30 a.m., the Germans blew the charge, filling the remaining British tunnels with carbon monoxide. The right and left tunnels collapsed and it was later found that the German explosion had detonated the British charge.

Sector of VII Corps
In the northern-most sector of the British front line, which was allocated to VII Corps in front of Gommecourt, no mines were prepared by the Royal Engineers for the offensive on 1 July 1916. The British Army would use the neighbouring villages of Hebuterne and Foncquevillers as bases for the assault on Gommecourt, resulting in a severe defeat for the attacking force.

Sector of VIII Corps
In the British front sector allocated to VIII Corps at Beaumont-Hamel, three tunnels were dug under no man's land, one to be a communication trench to the sunken lane and two dug to within 30 yd of the German front line at the Hawthorn Ridge Redoubt, ready to be opened at 2:00 a.m. on 1 July 1916, as emplacements for batteries of Stokes mortars. The 252nd Tunnelling Company dug a gallery for about 1000 yd from the British lines about 57 ft underground beneath Hawthorn Ridge Redoubt on the crest of the ridge and charged it with 40000 lb of Ammonal. The VIII Corps commander, Lieutenant-General Aylmer Hunter-Weston wanted the mine to be sprung four hours before the offensive, so that the crater could be captured and consolidated and the alarm on the German side would have died down. On 15 June 1916, the Fourth Army headquarters ruled that all mines should be blown no later than eight minutes before zero but an unsatisfactory compromise was reached with Hunter-Weston to blow the Hawthorn Ridge Redoubt mine ten minutes before zero hour.

Sector of X Corps


In the British front sector allocated to X Corps at Thiepval, no mines were prepared by the Royal Engineers for the offensive on 1 July 1916.

Sector of III Corps


In the British front sector allocated to III Corps at La Boisselle, the mines were planted at the end of galleries dug by the 179th Tunnelling Company of Royal Engineers, on either side of the salient around La Boisselle and were intended to destroy German positions and create crater lips, to block German enfilade fire along no man's land. On 4 February, 18 British soldiers were killed when the Germans detonated a camouflet near the British three-level mine system, starting from Inch Street, La Boisselle, the deepest level being just above the water table at around 100 ft. The Germans had fortified the cellars of ruined houses and cratered ground made a direct assault on the village impossible. To assist the attack, the British placed two mines, known as Y Sap and Lochnagar, on either flank. The Y Sap mine was located to the north of La Boisselle, and the Lochnagar mine to the south. (see map).

The 185th Tunnelling Company started work on the Lochnagar mine on 11 November 1915 and handed the tunnels over to 179th Tunnelling Company in March 1916. Other tunnelling units involved in the Battle of the Somme were the 174th, 178th, 181st, 183rd and 252nd Tunnelling companies. The Lochnagar mine consisted of two chambers with a shared access tunnel (see map). The shaft was sunk in the communication trench called Lochnagar Street. It was probably the first deep incline shaft, which sloped from 1:2–1:3, to a depth of about 95 ft. It was begun 300 ft behind the British front line and 900 ft away from the German front line. In the inclined shaft, about 50 ft below ground, a gallery was driven towards the German lines.

For silence the tunnellers used bayonets with spliced handles and worked barefoot on a floor covered with sandbags. Flints were carefully prised out of the chalk and laid on the floor and if the bayonet was manipulated two-handed, an assistant caught the dislodged material. Spoil was placed in sandbags and passed hand-by-hand, along a row of miners sitting on the floor and stored along the side of the tunnel, later to be used to tamp the charge. The tunnellers also dug a gallery across no man's land to a point close to the Lochnagar mine. When about 135 ft from the Schwabenhöhe, the tunnel was forked to form two branches and the end of each branch was enlarged to form a chamber for the explosives, the chambers being about 60 ft apart and 52 ft deep. When finished, the access tunnel for the Lochnagar mine was 4.5 × and had been excavated at a rate of about 18 in per day, until about 1030 ft long, with the galleries beneath the Schwabenhöhe. The mine was loaded with 60000 lb of Ammonal, divided in two charges of 36000 lb and 24000 lb. As the chambers were not big enough to hold all the explosives, the tunnels that branched to form the 'Y' were also filled with explosives. The longer branch was 60 ft long, the shorter was 40 ft long. The tunnels did not quite reach the German front line but the blast dislodged enough material to form a 15 ft high rim and bury nearby trenches.

The tunnel for the Y Sap mine started in the British front line near where it crossed the Albert to Bapume road, but because of German underground defences it could not be dug in a straight line. About 500 yd were dug into no man's land, before it turned right for about another 500 yd. About 40000 lb of Ammonal was placed in the chamber beneath the Y Sap mine. The Lochnagar and the Y Sap mines were overcharged to ensure that large rims were formed from the disturbed ground. Two smaller mines of 8000 lb each, were planted from galleries dug from Inch Street Trench, intended to wreck German tunnels. Communication tunnels were also dug for use immediately after the first attack but were little used in the end. The mines were laid without interference by German miners but as the explosives were placed, German miners could be heard below Lochnagar and above the Y Sap mine.

Sector of XV Corps
In the British front sector allocated to XV Corps at Fricourt, the tunnellers placed a group of mines known as Triple Tambour below the German lines. As in most other sites along the Western Front, military mining in the Tambour area had started well before July 1916; the French had carried out some mining operations here when they held this sector of the line, and British tunnellers began working there on mines as early as August 1915.

The three Tambour mines were loaded with relatively small charges of 9,000 lb, 15,000 lb and 25,000 lb which were detonated just before the infantry advanced on the first day of the Somme; one failed to explode. The site of these mines (photo) now appears as a small area of cratered ground in the field beyond the Commonwealth War Graves Commission's Fricourt New Military Cemetery. The land they are on is private property.

In the front sector allocated to XV Corps near Mametz, Bulgar Point was mined with a 2000 lb charge, a sap further west was mined with a 200 lb charge. Six other mines in the Mametz sector had charges of 500 lb each, four of which were planted by the British tunnellers south of Hidden Wood.

Sector of XIII Corps
In the southern-most sector of the British front line, which was allocated to XIII Corps in front of Carnoy near the Carnoy–Montauban road, mine warfare had been conducted by both sides during May. A 5000 lb mine was prepared under a German salient at Kasino Point and a 500 lb mine was prepared on the extreme left flank, intended to collapse German dug outs and destroy machine-gun nests. (In 1971, Middlebrook wrote that the Kasino Point Salient was between Mametz, Carnoy and Montauban and the mine planted there was one of seven large mines that were due to be detonated at on 1 July.) During tunneling at Kasino Point, the British broke into a German dugout but were able to cover it up, before the breach was noticed. (J. E. Edmonds, the official historian, wrote in 1932, that this incident occurred during the digging of Russian saps rather than the Kasino Point mine.)

Battle: 1 July 1916
The mines were detonated by the Royal Engineers in the morning of 1 July 1916, the opening day of the Battle of Albert (1–13 July), the name given by the British to the first two weeks of the Battle of the Somme. Nine corps of the French Sixth Army, the British Fourth and the Third armies, attacked the German Second Army of General Fritz von Below, from Foucaucourt south of the Somme northwards to Serre, north of the Ancre and at Gommecourt, which was 2 mi beyond, in the Third Army area. The objective of the attack was to capture the German first and second positions from Serre south to the Albert–Bapaume road and the first position from the road south to Foucaucourt.

The Hawthorn Ridge mine was detonated at 7:20 a.m.. The explosion was filmed by British cinematographer Geoffrey Malins who had his camera set up about 0.5 mi away. As soon as the mine blew, the heavy artillery bombardment on the German front line lifted and Stokes mortars began a hurricane bombardment on the front trench. British troops rushed the crater where they were engaged by machine-gun and rifle fire from the far lip and the flanks. Three sections of German infantry (about thirty men) of the 9th Company were killed in the mine explosion and $1 1/2$ platoons were trapped in their Unterstände (underground shelters), from which only two sections escaped. The rest of the company in a Stollen (deep-mined dug-out) survived but the entrances were blocked and the troops inside were not rescued until after the British attack. By 8:30 a.m., the only ground held by the 29th Division was the western lip of the crater. A German counter-attack by two platoons, bombed towards the crater from shell-hole to shell-hole and forced the survivors to retire to the British front line. Reserve Infantry Regiment 119 had 292 casualties, most suffered in the mine explosion beneath the redoubt. Casualties in the 86th Brigade were 1,969, of whom 613 were killed and 81 were reported missing.

Eight minutes after the explosion of the Hawthorn Ridge mine, the Lochnagar mine was detonated at 7:28 a.m., along with the other mines prepared for the First day of the Somme. The explosion of the Lochnagar mine was initiated by Captain James Young of the 179th Tunnelling Company, who pressed the switches and observed that the firing had been successful. The two charges of the Lochnagar mine obliterated 300 – of German dug-outs. Most of the 5th Company of Reserve Infantry Regiment 110 and the trenches nearby were destroyed. The Lochnagar mine lay on the sector assaulted by the Grimsby Chums, a Pals battalion (10th Battalion, The Lincolnshire Regiment). When the main attack began at 7:30 a.m., the Grimsby Chums occupied the crater and began to fortify the eastern lip, which dominated the vicinity and the advance continued to the Grüner Stellung (second position), where it was stopped by the German 4th Company, which then counter-attacked and forced the British back to the crater.

Though the mines on the British front were to be blown at 7:28 a.m. (the only exception being that at Hawthorn Ridge, see above), the Kasino Point mine was late because the officer in charge hesitated when he saw that British troops had left their trenches and begun to advance across no man's land. The German machine-gunners at the point opened fire and inflicted many casualties, so the officer detonated the mine which, instead of exploding upwards, sent debris outwards over wide area, causing casualties among at least four British battalions, as well as obliterating several German machine-gun nests. A witness wrote later

but the late detonation surprised and demoralised the Germans, whose fire diminished and the British swept over the German front trenches, making it the most successful mine detonation of 1 July.

Aftermath
William Orpen, an official war artist, saw the Lochnagar mine crater in 1916 while touring the Somme battlefield, collecting subjects for paintings and described a wilderness of chalk dotted with shrapnel. John Masefield also toured the Somme, while preparing The Old Front Line (1917), in which he also described the area around the Lochnagar crater as dazzlingly white and painful to look at. The land around the Lochnagar crater was eventually purchased by an Englishman, Richard Dunning, to ensure its preservation after he read the The Old Front Line and was inspired to buy a section of the former front line. The site attracts about 200,000 visitors a year and there is an annual memorial service on 1 July, to commemorate the detonation of the mine and the British, French and German war dead.