In the December the British Expeditionary Force suffered its first attack by mining. The British were themselves attempting mining and the Dehra Dun Brigade of the Indian Corps began a gallery from the cover of an orchard in its front line, in conjunction with a proposed attack. The tunnel was pushed 70ft to a point estimated to be within 13ft of a German sap and charged with 45lbs of guncotton explosive. Before it could be blown, however, heavy German mortar fire forced the position to be abandoned.¹¹ The Germans were preparing an attack by sapping immediately to the south, at Festubert, which they launched on 20 December. This was to be regarded as the first mining attack made on the British, although it was made by using bored charges placed in the ends of saps. The Germans managed to drive ten saps toward the front line of the Indian Corps. The 3rd Company of the 7th Westphalian Pioneers was responsible for completing saps 5, 6 and 7, which it took over when partly completed on 9 December. Six men under an NCO drove each sap forward and were relieved every 24 hours. The rain was relentless and the work arduous and hazardous. In the high water table in Flanders trenches were constructed half in and half out of the ground in the form of sandbagged ‘breastworks’. Work in Sap 6 was particularly hampered by working permanently in water. Some of the pioneers lost their boots in the mud in the communication trench and even took part in the attack with no boots. Ten metres from the British line the work became particularly dangerous, with heavy grenade attacks from the British. The Germans erected wire netting at the sap head to keep the grenades out and covered the last 4–5m with planks, throwing the evacuated spoil over them. Well aimed fire from British snipers in trees made the work particularly dangerous. The British, however, failed to keep the saps from approaching their lines. In Sap 6 the Germans were so close that at night they stole empty British sandbags. At 3m from the British front line, the Germans used hand-turned earth-borers to cut tubular bores several metres long beneath the British trenches. Through the soft sandy upper soil of Flanders this boring could be carried out silently and undetected by the garrisons of the trenches only a few metres away. They then charged each bore with 50kg of explosives, inserted electrical detonators and tamped. Blowing the charges would also have the effect of extending the sap into the British trench. The British twice got into Sap 6 but were ejected with grenades and seemed unaware of the bored charges. Sap 6 was completed and the mine charged in time, but while testing the circuits it was found that this mine would not function and could not be used in the attack.¹² A British attack on all the saps was prevented by infantry fire. The British got either side of Sap 5, but the two pioneers continued work in the covered sap while the infantry held off the attackers. The attack was made on 20 December. Three white flares were the signal for the pioneers in each sap to blow the charges, which would link the saps to the British front line, after which infantry were to flow right and left and capture the trench. They also placed a charge of 300kg beneath a house in the British front line, but this failed to detonate. Sap 7 first flew into the air, followed by Sap 5, where a perfect connection was formed and the attackers were rapidly into the British position. At Sap 6, where the circuit failed, the sap commander crept forward and pulled down the British sandbag breastworks to gain entry into the British trenches. In Sap 7 the blow did not reach far enough and it took the attackers three attempts before they pushed back the defenders. Nevertheless, ‘with the aid of the overpowering effect’ of the mines, the British in the first line were taken by surprise and were killed with grenades and bayonets or captured before they could resist. The second line, defended, according to the Pioneer historian, by ‘English mercenaries’, was also taken after a short fight. After the attack the British trenches were filled with their dead and the Germans ‘literally ran over corpses’.¹³ The impact of the mines was both moral and physical, the German report stating: ‘In the dugouts of the trenches which were destroyed by the mines, a large number of Indian corpses were found still sitting; they had apparently been suffocated.’¹⁴

Only after taking the second line was the attack halted by British machine-gun fire from the flanks. Repeated British counter-attacks were beaten off and the German report claimed that nineteen officers and 815 men were taken prisoner, while six machine guns and eleven small trench mortars were captured. The claim that 5,000 British dead were left on the battlefield was an exaggeration,¹⁵ but the failure of the British to hold off the methodical sapping attack was very alarming to the command. The British had put out no saps of their own and had not anticipated that the Germans would use bored mines to make the final breakthrough into their trenches. The British shortage of mortars, grenades, engineers and equipment, along with the suffering of Indian troops poorly equipped and suited for the winter conditions in Flanders, all contributed to the success of the German attack.

The day after the British disaster at Festubert General Foch, commanding the French Northern Armies, wrote to Joffre pointing out the severe effect of the fighting on his troops, especially on his units of engineers, and requested that more engineer units be transferred to the front and new units be formed. He pointed to the arduous nature of trench warfare, involving the defence and attack of strongly fortified positions, and said that his 8th Army holding Ypres was carrying out large numbers of sapping attacks as well as having constantly to repair roads damaged by the German artillery ranged around the salient. He also asked that new units be recruited from the class of 1915, which need not be trained in the full range of field engineering, but only in sapping and mining. General de Langle, commanding the 4th Army in Champagne, reported the lack of engineers on 23rd, asking Joffre to double the number available for three corps due to take part in his attack, in view of the increasing importance of sapping and mining.¹⁶ Joffre partly remedied the situation by taking territorial units of engineers from the interior and converting them to units of sappers and miners. In the meantime, on 30 December, he authorized armies to form auxiliary engineer companies from officers and men from other arms: ‘…who would appear to you to be able to enter this new formation, in consequence of their aptitude or of their occupation.’¹⁷

These units would not have the full range of equipment of a peacetime unit and would not, he intended, allow them to increase the number of sapping and mining attacks, but would enable them to push more actively those already in progress by providing double or more the existing labour. This led to the formation of specialized mining units in the French army.

The British, relying on a voluntary small Regular Army and Territorial Force, particularly felt the shortage of engineers. In September 1914, British GHQ recommended increasing the number of Field Companies per division from two to three to meet the new situation at the front.¹⁸ The Field Companies were fully engaged in providing accommodation and defence for the Army. Colonel Harvey, former Chief Instructor in Fortification at Chatham, was an assistant to General G.H. Fowke, the Engineer in Chief, and he later recalled the situation:

…the British army engineers had had no training to fit them for mining in the wet running sandy clay which was the soil they encountered on more than two-thirds of the British front in 1914-15.¹⁹

Two RE Fortress Companies that had carried out the siege practice at Lulworth in 1913 were in France, but they were even weaker in personnel than the Field Companies. 20th Fortress Company attempted mining ‘through the sandy loam into green sand’ and had to learn a difficult technique of sheet piling, or ‘spiling’:

I think I took part in the earliest mining which was at Rue de Bois... This was in January 1915. The trenches there were only about 30 yards apart. I was a subaltern in the 20th Fortress Company. Was sent with my section to put in a mine to protect their (infantry) trench against alleged mining. Infantry were up to their necks in water. It was a pretty gloomy business. We started sinking this shaft and it filled with water, so we pumped it out with hand pumps (lift and force). We got down about 10 feet or so. It was heartbreaking – I hated it. Had a job to keep my men going. The Boche saved us. We were making a lot of noise with spiling. The Boche opposite us were Saxons, rather friendly, and they put up a notice on a blackboard, ‘No good your mining. We’ve tried. It can’t be done.’ The notice was in English. I reported this to my OC and it went up to HQ and they stopped the mining. (Lt. F. Gordon Hyland, 20th Fortress Company, RE)²⁰

All RE units lacked the personnel to allow the continuous shifts needed for mining. At the end of December General Rawlinson, commanding the 4th Corps, asked for a special battalion for sapping and mining, which was supported by General Haig, commanding the First Army, who asked for a similar unit to work on the 1st Corps front at Givenchy.²¹

In very late 1914 or early 1915, the newly formed Armies of the BEF ‘were instructed to proceed with offensive sapping and mining with such suitable personnel as they could find in the ranks, formed into “Brigade Mining Sections.”’²² In the meantime, a letter had been received at the War Office which, were it not for the influence and reputation of the writer, would have been dismissed with the many other letters received from cranks. A Member of Parliament and engineering contractor, Sir John Norton Griffiths, suggested employing the men that he used for carrying out sewerage contracts on mining at the front:

In thinking over the position that was taken up so early in the war, of opposing trenches being so near together, as an old miner the idea of undermining and blowing up the enemy occurred to me. As early as November, 1914, I sent in a scheme to the War Office and begged permission to be allowed to take out a handful of men, whom I described as ‘Moles’, and make a start; but although the scheme was listened to sympathetically, and, indeed, was sent out to France for approval, it went no further...²³

Griffiths’s curious memorandum stipulated that the training and equipment of the Moles should be left to the officer commanding, by which he meant himself. He should also ‘have as free a hand as possible in advising when and where he considers, as a technical expert in these matters, the “Moles” should be used.’ While he made a careful study of the ground to be mined at least 100 of his ‘Moles’ would be trained 10 or 20 miles from Chatham, although they could be used at the earliest possible moment with little training except in the use of the rifle and bayonet.

The suggestor [sic] of the use of “Moles” who has handled this class of men for many years is convinced that, given a fairly free hand, their use will prove of such importance that a very much larger number than at present anticipated would be asked for by the early spring. Water or adverse weather conditions would not necessarily affect the usefulness of these men.²⁴

According to Harvey, his proposal reached GHQ from the War Office on 28 December, but, writing after the war, Harvey recalled details which he may only have learned later, in particular:

…that certain men specially skilful in tunnelling clay – termed clay-kickers – were admirably suited for mining and sapping. As the soil on the British front was all clay of a sort his suggestion was at once agreed to and a demand for 500 of such men… sent to the War Office.²⁵

According to Norton Griffiths his proposal got no further until 13 February 1915, when he received a telegram to report immediately to Lord Kitchener at the War Office. He described the meeting at a reunion of British Tunnellers in 1927:

Alone in his room at the War Office he showed me the urgent despatches which had been coming from Lord French, to the effect that unless some means could be found of checking the mining efforts of the Germans, he (Lord French) would probably have to withdraw certain sectors of the line. Lord Kitchener, to whom I had had the honour of being known, both in the South African campaign and in Egypt, asked me to amplify my suggested mining scheme. Just before this interview the Boche, it will be remembered, had given us a nasty blow at Ypres, had lifted, almost en bloc, most of the officers of one of the Lancers regiments then in the trenches in the Ypres sector, in a dug-out near Hill 60, and had buried some 22 or more at Givenchy, in addition to several minor mines they had sprung in our front trenches.

To his demand I replied that the only thing I could suggest, subject to examination of the ground, would be to use ‘Moles’. When he said, ‘What on earth are “Moles”?’ I said, ‘Clay Kickers, or workers on the cross’, using a North-country expression for this class of small tunnel mining. As his patience showed signs of giving way, I then proceeded to demonstrate, much to the amusement of Major-General Sir George Scott Moncrieff and others of the Army Council with the fire shovel from the War Office grate, and showed him lying on the floor, what a Clay Kicker really was, and what a small hole he could work in, with the result that he turned round and said, ‘Get ten thousand immediately.’ I replied that I did not think there were ten thousand in the British Isles, and that it would be necessary to examine the ground before one could ascertain whether this form of mining were possible. The result was I was off that very night to France, with two of my expert London underground tunnellers who were employed on important underground works at Manchester for that Corporation. (Sir John Norton Griffiths MP)²⁶

Norton Griffiths was to have a profound impact on British mining capacity.

In the New Year mining over much of the Western Front rapidly escalated. West of the Argonne lay the Champagne region. The area of Hill 191, between Massiges on the French side and the hill called by the Germans Kanonenberg, was taken and retaken and saw the early acceleration of mine warfare. From Hill 191 the French had observation deep into the Aisne valley in the German rear. After spotting French spoil heaps, by means of mirrors on the trench parapet, the German pioneers embarked on countermeasures and sapped to within 20m of the French trenches. After several attempts to storm the trench failed with heavy casualties, they continued sapping on the night of 8 December and used mining to get to within 5m of the French positions. On the following evening they charged a mine and, once infantry were in place, the pioneer officer lit the fuse ‘using a cigar - matches were inappropriate because of the proximity to the enemy’.²⁷ The charge blew a path into the French trench and also by chance detonated a French mine, destroying a significant part of the position.

On 20-21 December the French Colonial Corps launched a major attack and took the whole of the Massiges position, leaving the Germans 500 to 600m from the summit of Hill 191. The side of Hill 191 facing the Germans presented a steep escarpment and the Germans proceeded to sap up to the foot, from where they would be able to mine into the side of the hill protected from observation and fire. As the saps progressed, the French fire on them became heavier, forcing the Germans to sink their saps more deeply. The French also began to push forward saps, attempting unsuccessfully to counter the German advance, and, in the words of Captain Arndts, commanding the 4th Ruhr-Hessian Pioneers, ‘on both sides the saps strained forwards like antenna.’ By connecting the sap heads about 50m from the French a new trench system was formed as a base from which to begin the mining operations. The French made a determined attack to push back the Germans on 28 December but, after heavy grenade fights, the Germans regained control of their positions. The Pioneers used aerial photographs to assist in forming a survey accurate enough to begin mining and started driving six tunnels into the chalk at the end of December, four of which were against the escarpment position of Hill 191. The amount of work was such that a reinforcement company was placed under Arndts’s control. In line with siege practice, Arndts also dug a transversal defensive gallery running across his position from which listening could be carried out for French countermines. On 7 January they heard noises from the tunnel on the right flank, forward 20m, and from other points. Arndts blew a charge from his tunnel 3 on 9 January and the French occupied the crater until the Germans drove them out with grenades. On 13th, the French blew charges against tunnels 1 and 2, but without success. As the German tunnels progressed the pioneers could hear the French underground in front and on either side. The chalk conducted sound some distance and the Germans began to deliberately intensify work in the two defensive tunnels to mask the progress of the main attack galleries (1, 2, 5 and 6). On 21st they established by listening that the French had reached very close to the main galleries 5 and 6 and were able to blow one of the defensive galleries without damaging their attack galleries. The French miners still came on and could be heard continuously at work from all the German galleries:

Those who saw such mine warfare at its peak know what pressure on the nerves this underground struggle costs. Furthermore they know what sense of duty and what contempt for death are demanded foremost of the honest pioneers in the mining section who, in short breaks from work, strained to listen deep underground in bad air which hardly supported breathing... (Regimental historian of Ruhrhessische Pionier Bataillon Nr. 11)²⁸

In the early hours of 23rd, the French blew against tunnel 2, destroying the defensive tunnel. They blew again shortly afterwards and a third time at 5pm, reaching close to the shaft of tunnel 2. It was vital that the French were stopped before they could destroy the shaft, as this would seriously set back the work. Throughout the night, in conditions of maximum quiet and care, the Germans loaded a large charge in tunnel 2, tamped and fired it. This was effective in halting French work in the area. On 26th, 27th and 28th there were alternative French and German blows at tunnels 6 and 4, but the main German galleries remained intact. The German deception measures apparently prevented the French from identifying the main threat. On 27th the four main galleries measured between 35 and 45m and the order was issued to enlarge the ends for each to take 5,000kg of gunpowder. Special carrying parties were organized to bring the 20,000kg of gunpowder into the trenches. Carrying the boxes of powder through the long saps exposed to French fire was particularly dangerous, as it was liable to be detonated by impact or naked flames. On the night of 30 January, tunnel 5 had been charged with about 4,000kg when some ignited at the tunnel entrance, but it burnt itself out before reaching the main charge. Charging was completed by the night of 1 February and the charges fused and tamped. The blowing of the mines was scheduled for 3 February and was to be followed immediately by an infantry attack. Heavy French shelling was directed particularly on the jumping-off trenches from which the Germans would attack, and on the morning of the attack this broke the detonator leads in several places, which had to be quickly repaired in time for the attack.

The mines were in two groups of two and the firing, carried out by Lieutenants Kühn and Oehlmann, was described by Arndts:

It was an unforgettable sight of terrible beauty, when on this day - zero 12 midday - four enormous columns of earth, each about 100m high, with a dull crash ascended high into the air, and then collapsed majestically onto themselves. How then the earth from four craters spat out enormous masses of smoke, which veiled the whole area. It was the largest blow which had been carried out up to then on the western front. Over 400 hundredweight of powder was detonated at the same time. Complete portions of the enemy position flew into the air. The stone hail had hardly rained down when the infantry with the pioneers stormed forwards.²⁹

An eyewitness description of the assault appeared in the Frankfurter Nachrichten:

We had worked feverishly four months long and for the last four days without sleep in order to make all preparations to make the attack. Mountains of small scaling ladders lie ready to be carried forward at night and all the equipment – shields, entrenching tools, flare cartridges, sandbags, ammunition etc. – lies ready brought up overnight. Now morning comes. Ceaselessly man after man trudges forwards with timbers, scaling ladders and equipment. Their boots stick over the ankles in the tough mud and with trouble they climb step by step the stairs, well-worn by hundreds of heavy boots, upwards to the copse. We move forward. The assault columns are already standing at the ready. Still some quietly spoken words and a handshake with the column commander. Watches are synchronized one last time. The slight rifle fire is as normal and betrays nothing of what is approaching. Again we check the time, still five minutes, then from four places in the enemy front line will be detonated the mines which our pioneers previously placed with indescribable troubles over 50m away under the enemy position. Now two minutes to go. We stand crouching in the trench – still ten seconds – then one second – two muffled explosions. I see, like volcanoes, as high as a house – no a steeple – four black fountains of earth. Human body parts, cubic metre-sized lumps of earth fly, turning ponderously, into the air. It grows dark. Masses of earth now come clattering down. Many men are buried up to the waist. They must be dug free.

Nearly in the same instant, without wavering, the assault wave of our column takes the mine craters. Terror has seized the enemy. Already numerous prisoners are appearing who, escaping the explosion, wish to save themselves by promptly surrendering. Right and left, in unison, the storm columns jump forward. With the motto ‘on, then through!’ the second and third lines of enemy trenches are also taken in a rapid assault.³⁰

In fact many attackers were injured by falling debris from their own mines, having been too close to the blows.