Opportunity for Breakthrough

During the 'first phase' * of mining on the British and Commonwealth side, operations had been defensive and local in nature, with the notable exception of the Hill 60 offensive in April 1915. The experience bought during this period enabled the British, not only to equal German mining efforts, but also to exceed them, culminating in the largest and most successful mining offensive of the war at Messines in June 1917. The success at Messines was the high water mark of the Tunnelling force and showed their worth as an effective fighting organisation when used in a wider strategic sense in co-operation with other arms. During the 'muddled' nature of the command structure of tunnelling companies until its reorganisation in early 1916, some opportunities may have been lost and others squandered. In examining whether or not mining offered the possibility of a breakthrough earlier in the war before greater defence in depth rendered this unlikely, then a further look at the conditions prevalent at the time and also at some of the mining offensives that were undertaken will be necessary.


The first mining offensive made by British tunnellers was against Hill 60 in the Ypres salient early in 1915 †. Hill 60 was the largest of three artificial spoil banks, created from the excavated earth from the cutting in the Ypres Ridge, through which passed the Ypres-Comines railway line. The other two mounds, located on the opposite side of the railway line, were known as the 'Caterpillar', due to its unusual shape, and a conical shaped hill known as the 'Dump'. The German Army had pushed the French from this vital piece of high ground in early December 1914 and from this vantage point commanded Ypres and much of the opposing line. In order to retake the hill French Sappers had commenced mining from one of their front line trenches but had made little progress by the time the British took over this part of the line at the beginning of 1915 (1). It was decided to continue to mine the hill from three shafts designated M1, M2 and M3, the latter being the original French attempt, and each of the galleries split to form pairs and packed with gunpowder and guncotton (2).


The mines were fired successfully on 17 April 1915 and an artillery bombardment of the hill and surrounding area preceded an infantry assault. Initially the operation seemed a complete success but as the day wore on and the Germans reorganised themselves it became apparent that 'a costly tactical blunder had been committed' (3). The hill pushed into the German front line and was now exposed to heavy artillery fire from two sides and from the Caterpillar nearby. It seemed at first that the German artillery was firing wildly but this was due to the fact that they did not have their guns ranged on 'what had been their own hill, and anyway shelled behind the line chiefly with a view to catching our reserves and preventing reinforcements coming up' (4). The British position on the hill became untenable and, under such fierce bombardment, the use of poisonous gas and almost continuous counter-attack, it was finally lost on the 5 May with the loss of 100 officers and 3,000 men (5). That the mines themselves were a success in not in question. The operation as a whole, when compared with the offensive against Messines two years later, 'was on too limited a scale' (6). Greater success may have been achieved if the 'Caterpillar' had also figured in the assault. The capture of this elongated mound would have denied the Germans' this position from which they were able to subject the British forces occupying the shattered hill to continuous enfilade fire. The reasons for this omission may be due in part to the command structure of the Tunnelling companies that was in place at this time ‡, and the lack of value some senior officers placed in the use of mines in a wider strategic sense.


The fighting on the Western Front during most of 1915 was of necessity limited in nature and those offensives that were made were on narrow fronts. The first major assault was a combined offensive on a much wider front involving French and British troops which commenced on 25 September. The British objective was to be the 'low ground of the Loos sector' to the left of the French attack at Artois. Despite the fact that the nearby town of Lens was a mining area 'mining was to form no part in the preparations for battle'. The only mining undertaken was that in front of Hooge in the Ypres salient, some considerable distance to the north. Four mines were fired here in an attempt to attract attention away from the battle about to commence in front of Loos (7). The preliminary artillery bombardment was lacking due to the shortage of ammunition and the use of poisonous gas was largely ineffectual as it blew back on British positions in certain areas. Nevertheless Loos was almost a success. In some places small units managed to break through the last German line of defence and 'German headquarters as far back as Douai prepared for a hasty departure' (8). The majority of the attacking force, which had a seven to one advantage, was lost at the German first line of defence. Had the firing of a number of large mines preceded the assault then the outcome might have almost certainly been different. In the event the area was only given over to mining once the battle was over.


The use of mines to aid an offensive on a much larger scale came with the Battle of the Somme on 1 July 1916. Much had changed since 1915. Douglas Haig had replaced the Commander-in-Chief, Sir John French, who had not been a great advocate of mining. Haig, on the other hand, saw the potentialities mining had to offer in aiding a major offensive. The Tunnelling Force itself now had a direct voice at GHQ through the newly appointed Inspector of Mines, Brigadier-General Robert Napier Harvey. Harvey decreed, in the first of his 'six-point overhaul of tunnelling procedure', that 'there was to be no offensive mining unless it formed part of a thought-out military operation involving the use of surface troops also' (9). It was decided therefore, that mining would form part of the coming offensive on the Somme and five tunnelling companies were given over to the task of preparing eight large and eleven smaller mines to be ready for firing just prior to the assault by the infantry ±. Besides mining the Tunnelling companies also had to provide 'Russian saps' Ŧ to be driven out into no-mans land to be used as communication trenches once the battle had started. Despite such short notice - only three months had been given - the mines were ready before the date given for the offensive to begin. Once again the mines, with the exception of one, were fired successfully. The offensive however, was the biggest disaster in British military history to that date with almost 60,000 casualties on the first day, half of them within the first hour, with some 20,000 men killed


Arguably the biggest tactical mistake was the premature firing of the large mine beneath Hawthorn Ridge Redoubt. This was fired at 7.20; ten minutes before the attack was due to commence. The original plan had called for all the mines to be fired two minutes before zero at 7.28 in order to take full advantage of the confusion the mines would cause. The decision to fire the mine early was taken by the local corps commander, Lieutenant-General Sir Aylmer Hunter-Weston. Initially he had planned to fire the mine four hours before zero with the objective of rushing and securing the crater in order to give covering fire once the main assault began. The time lapse, he argued, would also give the impression that this was an isolated assault, adding to the surprise of the main offensive when it began. The Inspector of Mines, Brigadier-General Harvey, thought the plan 'mad beyond belief'. The Germans were far more successful at rushing craters, 'as Harvey had sorrowfully noted, not one major mine-crater had been effectively held by the British' (10). Despite Harvey's protests that the original plan be adhered to it was eventually decided that the Hawthorn Ridge mine would be fired ten minutes before zero.


The mine was  a complete success. The 'Redoubt itself was utterly destroyed' (11) and three sections of the German 119th Reserve Regiment had been killed in the blast with many more buried in their dugouts. A section of Lancashire Fusiliers raced to occupy the crater but, as Harvey had predicted, the Germans managed to get to their side first. More significant is that the early firing had alerted the Germans of the impending assault and they were now in a position to repel it. The Russian Saps that had been constructed by the Tunnelling Companies were not used as intended. This was due to poor staff organisation. The saps had been constructed in secrecy and many of the attacking troops did not learn of their existence until after the disaster of the first day had overtaken them. Tunnelling Officers well forward into no-mans land, under cover of the saps, observed wave after wave of reinforcements struggling in vain across the bullet swept landscape while an advance in relative safety was but a hundred yards away and had begun in their own front line. In those places where the saps had been used runners, reinforcements and supplies were delivered to their destination with very few losses (12). The official historian gives another factor in the failure of the Somme offensive to reach its first day objectives: 'though many mines were fired, they were too much scattered up and down the front to produce a noticeable effect on the enemy' (13). Given the length of front, the amount of notice given and the numerous other tasks that the Tunnelling Companies had to carry out, of which only five were allotted to the Somme region +, the tunnellers did all that was asked of them. Time perhaps was an important factor. Given more time, as with the Messines operation, the mining operations on the Somme may have produced the same kind of results that the former did a year later.

The year 1917 witnessed a series of allied offensives on the Western Front, the bulk of which were undertaken by the B.E.F. These were: Messines (June) followed  by 3rd Ypres (July), Cambrai (November) and to set things rolling the battle of Arras at the beginning of April. Arras was planned as diversionary operation to draw German reserves north from the main offensive by the French on the Aisne. The new French Commander-in-Chief, General Robert Nivelle, claimed that artillery techniques he had developed during the Battle of Verdun, along with massed reserves, would produce a breakthrough in the German lines within 48 hours. Although the offensive failed to live up to Nivelle's claims there was one notable success; the capture of Vimy Ridge , a stretch of high ground approximately nine miles in length, to the North of Arras. The British had taken over this sector of the front in the spring of 1916 at the request of the French following the German onslaught at Verdun. An advanced party, containing Frederick Mulqueen, the commander of 182 tunnelling company, discovered that the front line defences were 'little more than shallow mine craters linked by mean straight-line trenches' (14). The French had attacked and taken the northern tip of the ridge in September 1915, a feat widely publicized at the time. However, the situation had been reversed prior to the British take over but this fact had not been made known. Clearly the tunnelling companies had their work cut out.

The tunnelling companies in the Arras sector were straight away thrown onto the defensive, the Germans already having established a definite system. The British were also hampered by the unfamiliarity of the French system they had inherited. The French had been using a system of "rambling tunnels" that had been in place for many years and had had some successes against the Germans using this system. Discussions with Captain Mulqueen's French counter-part however, revealed suspicions that German miners may already be well forward in this sector. The mines in this system were also difficult to enter and in certain instances were well forward and exposed with some entrances having been severely damaged and narrowed by shell fire (15). In addition,  Mulqueen feared that the Germans may stumble on these uncharted, ready made tunnels in the same way the French had done and cause greater problems for the incoming British forces. Shortly after his visit to this particular system the whole of one gallery was destroyed by a heavy German camouflet, a taste of things to come.

A mining stalemate followed a period of fierce activity that culminated in a local German offensive, the result of which was the lost of much of 182 company's mining system at the end of May, forcing them to begin constructing seven new galleries from the new front line. From June onwards there was a fall off in German underground activity. Such a drop in activity, argues Grant Grieve, should have alerted the intelligence sector to the possibility that German pioneers were engaged elsewhere. Hindsight showed that they were actually busy fortifying the Hindenburg line. There was also the fact that by the end of 1916 the blockade was beginning to bite hard on the German economy which had forced the recall of some 125,000 miners from the army to bolster the work force at home. The drop in German mining activity in this sector meant that more tunnelling companies could be employed in the construction of infantry subways, Russian saps and underground assembly areas in preparation for the coming offensive. It was this work by the tunnelling companies that proved invaluable to the success of the Vimy operation. On the whole of the Arras front over half of the assaulting battalions were able to take up their starting positions at the last minute from the relative safety of the tunnels and caves created by the tunnelling force (16).

The lessons of 1916, particularly in artillery developments and techniques, became clearer and were applied during 1917. More than twice the number of guns were arranged along the Arras front than had been present on the Somme on 1st July which had a longer front. The preliminary bombardment was for a longer period - three weeks - and the targets more selective. As well as bombarding the front line trenches and wire entanglements, road junctions and other key points in German communications were also targeted on a regular basis along with ammunition and supply dumps, dugouts and machine-gun emplacements. There were, however, certain strong points that were situated in artillery-proof dugouts which if left would cause heavy casualties to the Canadian divisions ear marked for the assault. Initial planning had called for some twenty-six strong points in front of the four attacking divisions to be destroyed with mines.

The corps staff planners were concerned with the affect that further mining would have on the movement of the assaulting force.  A visit to the Somme battlefield  - arguably the most heavily mined sector on the Western Front - put their minds at ease as local commanders explained that the craters there were easily traversed on a regular basis by raiding parties and patrols by the British and also by the Germans. Within the four miles of the front that the Canadian divisions were to attack there were some nineteen distinct mine crater groups that had been fired by the British, French and German miners and it was concluded that in all but four of these groups the craters would pose no problems to movement. Despite this, local Canadian commanders were not convinced and believed that further mining would only add to the problem of movement particularly in keeping up with the creeping barrage intended to protect the infantry advance (17).

The initial plan had called for twenty-six large mines in support of the operation. Following discussions with his subordinate commanders the GOC, Sir Julian Byng, heeded their concerns and the offensive mining operations were reduced. 'Four mines were abandoned due to technical difficulties, two were detonated before 9 April for defensive purposes, five were fired as planned, eight were prepared but not used and seven others, though mentioned in the earliest stages of planning do not appear in subsequent tunnellers' war diaries as having been undertaken'. Arguably, the hardest task was in the area of the 4th division. The objective was Hill 145 which was well defended by a heavy machine-gun emplacement in a German redoubt that had been nicknamed the Pimple. This emplacement had been selected for destruction, along with  a mutually supporting position in le Bois de Givenchy, just north of the Pimple, by two large mines. However, work had been halted on these mines due to technical problems. The mine being driven towards the Pimple was collapsed by the corps own heavy artillery that fell short of its intended target. The shallow depth of the tunnel in general and the concentration of shell-fire in that sector forced the abandonment of the operation and the mine was duly closed. The second mine was abandoned when it seemed that it would not be completed in time. 'On the morning of the attack, that tunnel was only 100 feet from its target' (18). Ironically it was this sector that proved most difficult. Had these mines been in place and fired it may be argued that the losses would have been greatly reduced and made the advance of the 10th and 11th Canadian infantry Brigades much easier. Nevertheless, three mines were fired in the assault of Hill 145 which enabled the 73rd battalion to seize the farthest rim of the newly formed craters which gave a strong defensive flank for the 72nd and 38th battalions attacking from the south. Although the general offensive as a whole failed, this limited objective operation had secured for the allies an important piece of high ground. There were some seven miles of tunnels and subways constructed in the Arras sector in a period of four months. It was possible for the assaulting troops to travel two miles from Arras and appear at the German front line in safety. It was this feat, along with the construction and firing of several mines at the moment of the assault, that was an important contributing factor to the success in the capture of Vimy Ridge.


The mining of the Messines-Wytschaete Ridge on the 7 June 1917 was a preliminary offensive to the larger Battle of 3rd Ypres. Its objective was to seize and hold the high ground that the ridge had provided for the Germans, while at the same time straightening the forward bulge that pushed into the British line in preparation for the much larger battle that was to follow. Initially the Ridge was to be mined, as part of a secondary attack in 1916, should the Somme offensive fail. The commander of the 2nd Army, General Sir Herbert Plumer, was asked to prepare plans for an offensive in the Flanders area to that end. The idea of mining the Ridge was originally conceived in May 1915 by Major J. Norton Griffiths, the man most directly responsible for the formation of the Tunnelling Companies. Initially his plan was rejected because of its lack of detail. Along with Harvey he produced a revised plan which involved the use of deep mines, between 55 to 125 feet in depth, along the whole of the German Front from Hill 60 in the north down to Factory farm in the south. This was designed, not simply to blow the top off the Ridge but to create an artificial 'earthquake' that would shake the Germans off. Mining at this depth would not only produce the desired effect but it would also prove difficult for the Germans to detect the work being carried out beneath them. The fact that only one of the twenty-two mines constructed was destroyed is, perhaps, testament to this theory. The plan was eventually approved by G.H.Q. and was to form part of the secondary operation outlined above. The confusion of the Somme offensive - that the battle was being won - and the numerous reserves required maintaining the offensive meant that the secondary offensive in the Flanders area was cancelled.


Although the Flanders offensive was called off, preparations were continued as General Plumer concluded that an assault on the Messines Ridge would have to take place sooner or later. Indeed, mining in this sector had commenced as early as 1915 when General Allenby, then in command of V corps, ordered a deep mining offensive directed towards Hill 60 and the Caterpillar (19). In all 21 mines were prepared and ready for firing by the 7 June, of which 19 were actually fired. The length of the galleries in many of the mines exceeded any that had gone before. Some began 500 yards behind the British front line and pushed on towards their German objectives, the total length of which was anywhere from 1,000 to 2,000 feet, branching to form one, two or three chambers each filled with an average of 40,000lbs of explosives. The result was a combined explosive power of some one million tons. In fact some of the mines had been in position for over a year and there was the fear that these older mines might have deteriorated by the time zero hour came or that enemy counter-mines may discover them. Constant checking of wiring and explosives had to be carried out and listening parties strained for signs of an approaching enemy mine. The Ridge itself had been heavily fortified with concrete blockhouses and pillboxes (20) over a wide area; therefore, accurate surveys had to be carried out in order to ensure that these defences were destroyed when the mines were fired. 'This was made possible by using an excellent series of aerial photographs specially taken for the purpose' (21).


Like the preparations for the Somme offensive, here too the Tunnellers were engaged in other preparatory work. While a mixture of British and Commonwealth Tunnelling Companies, British, Canadian and Australian *1, were engaged in maintaining completed mines or hastily completing those as yet unfinished, other companies were engaged in the construction of huge mined dugouts. Also 'numerous subways were made, some 15,000 feet of gallery being provided' in all (22). Both constructions were undertaken to provide protection and to enable the concentration of the attacking force in relative secrecy.


Designed as a 'single-action bite and hold' operation, to be 'closed down' as soon as its limited objective had been reached (23), the Battle of Messines illustrated how far the B.E.F. had come in its tactical and strategic planning since the Somme offensive in 1916. It was an all-arms operation of which mining played a vital part. There were also some 2,338 artillery pieces covering a front of just over nine miles, augmented by 304 large trench mortars, giving an approximate concentration of fire power of 'one gun to every seven yards of front' (24). Tanks were massed in the rear ready to roll forward once the mines had been fired. However, such was the force of the mines, the accompanying artillery barrage and the destruction of strong points so total that the tanks were not needed. Of the 21 mines prepared, General Plumer decided not to fire the two southern most charges as he deemed these too far south to be useful to the attack. Nevertheless he ordered them prepared just in case they were needed. Following the German Spring Offensives in 1918 the exact location of these two mines was lost. One exploded in 1955 during an electrical storm but caused little damage; the position of the remaining mine is still unknown.


At 3.10am on the morning of the 7 June the mines were fired. The surprise on the part of the German Garrison was complete. So enormous was the blast that it was clearly audible in London 130 miles away. German soldiers panicked further down the line believing an earthquake had begun. The extent of German casualties' cause by the blast of the mines was not officially recorded. 'But by the end of the battle, 10,000 of their own men were missing (besides known dead) and 7,354 had been taken prisoner - many so dazed that they hardly knew who or where they were (25). The demoralisation of the Germans on the Ridge was such that little resistance was offered. The attacking infantry, expecting a hard fight, was almost unopposed. The whole of the Ridge and the villages of Messines and Wytschaete were in British hands by 9.00am with comparatively few losses. Following waves of infantry crossed to the ridge without having to fight. However, this produced serious overcrowding on the crest and made easy targets for the Germans. It was only at this point that any serious casualties occurred. So rapid had the operation been that later the same afternoon the 3rd Canadian Tunnelling Company, who had prepared and fired four of the southern most mines, began work on repairing the Wulverghem-Messines road (26), with many more companies engaged in repair work and in consolidating the new front-line defences.


The success of the mines at Messines was due to a number of factors. 1. The mixture and weight of the charges within each chamber †. 2. The depth of the shafts and the length of the galleries, producing greater destructive power and relative secrecy from detection. 3. The length of front covered, almost ten miles, and the number of mines used. 4. The extraordinary length of time between the completion and firing of some of the mines, 'due to the cancellation of the 1916 offensive, the original scheme having been partly completed'  (27). The destruction of the German strong points, and the complete demoralisation of the defenders allowed the infantry to cross the normally bullet swept expanse of no-mans land to take their objectives with a fraction of the casualties that would almost certainly have occurred without the use of mines prior to the attack.


Messines was the last mining offensive of the war. The British and Commonwealth tunnellers, after a shaky start in December 1914, had finally overcome their German counterparts and had in effect mined them to a standstill. What did the future of mining now hold? It was largely hoped that such a system of warfare would never occur again. The Inspector of Mines, Brigadier-General R. N. Harvey, stated while giving a lecture to trainee Royal Engineers in 1929: "if you are in a position of responsibility in the next big war, do everything you can to prevent mining being done . . ." (28). One volunteer Tunnelling Officer, Capt. Frayling, following the advice of a senior regular officer, had considered remaining in the Royal Engineers at the end of the war, although he would revert to his substantive rank of second lieutenant. He could not afford the peacetime pay that a subaltern earned and had no private income. However, he stated that 'the deciding factor was that I was told there would be no peacetime tunnelling companies' (29). The only reference to mining came from the former head of the mine rescue school, Lieutenant-Colonel Dale Logan, in 1938. He suggested that deep dugouts should be prepared, similar to those that housed the attacking troops at Messines, to provide shelter against possible air raids.