The British did not blow at the Bluff itself, but maps survive for two extremely ambitious schemes to the south, which bear the signs of being inspired by Norton Griffiths. The first was to lay four large mines around Eikhof Farm and the Dam Strasse, from a tunnel which would have measured about 4,320ft, including 1,500ft behind the German lines.²⁹ This was attempted with a tunnelling machine, one of two tried by the British, but it was not a success and the scheme was abandoned. An even more ambitious scheme was planned just south of this. A plan from late 1915 shows a long drive of about 4,700ft from Bois Carré behind the British lines to Grand Bois 2,300ft behind the German front line, from which seven charges totalling 240 tons were to be laid. It is probable that this was also planned using a machine, as the labour required would have been considerable.³⁰ South of this area were the schemes conceived by Cecil Cropper. On the left of the sector of 250 Tunnelling Company, the gallery that he obtained permission from the Canadian Corps to drive went under the Hollandscheschuur salient, or Nag’s Nose, where the German line enclosed a piece of high ground. German shelling of the shaft head caused flooding to the tunnel and the objective had to be reduced to three charges laid within the salient. The British drove a gallery 825ft into the rear of the salient. The St Eloi blows caused the Germans to be considerably more alert to any indications of British mining and in June 1916 they heard sounds beneath their lines at both Petit Bois (known to them as Alfweg Cabaret) and Hollandscheshuur. They hurriedly sank timber-lined shafts to meet the noises and managed, despite the wet conditions, to get them to 5m. As the British were completing their gallery the Germans fired charges from shafts Cöln and Cassel in their own lines at the shoulders of the salient. The British managed to repair the damage and laid three charges in June, July and August 1916 of 34,200lbs, 14,900lbs and 17,500lbs at between 55 and 60ft. The Germans blew a very heavy camouflet on 10 February 1917, but the British were able to repair the damage.³¹

Cropper began the Petit Bois tunnel in late 1915 from the ruins of Van Damme Farm 500yds behind the lines, and sank a shaft 97ft into the clay. In February 1916 he sank a second shaft for a tunnelling machine that was to be unsuccessful. From the first shaft, however, he made good progress by clay-kicking of 100 to 150ft per week and the tunnel passed beneath the German front line and was branched into a ‘Y’. From the bottoms of shallow shafts at Petit Bois the Germans could hear the voices of the British miners and they blew two heavy charges on the morning of 10 June at the shoulders of the salient just in front of their front line. These produced deep craters, but the Germans noticed that very little debris was thrown up by the northernmost charge. In fact the charge was almost directly above the British main gallery and the wet sand had poured down into it, completely blocking it beyond the 1,250ft point. It also trapped twelve men at the face. A rescue was immediately embarked on to dig around the collapsed portion to reach the cut-off miners. The rescuers worked continuous shifts, digging 40ft a day, but the tunnel was collapsed for 250ft and it took six and half days before they re-established contact with the lost portion. Graves had already been prepared for the miners when they broke into the gallery. They found eleven bodies – the twelfth was assumed buried under the debris – and they left the gallery to allow the air to clear. When they returned they found a man at the opening, alive, who said to them: ‘For God’s sake give me a drink! It’s been a damned long shift!’ The man’s name was Sapper William Bedson. When the explosion had occurred, the trapped men had gathered at the end of the gallery nearest the collapse, where a tiny amount of air was coming through a pipe, and took it in turns to try to dig themselves out. The next day at 3.00am they gave up and spread themselves out along the gallery. One man died that afternoon and by 8.00pm on the third day only one was left alive. Bedson, 36 years old, was an experienced miner who before the war worked at Cadeby Main Colliery. On 9 July 1912 an explosion had killed thirty-five men and a second about eight hours later had killed fifty-three rescuers. Bedson’s role in these events is not known, but his experience led him to remain at the far end of the face, which was a little higher, where the air might be better. He had two ration biscuits, which he did not eat, and a water bottle which he used to rinse his mouth before returning the water to the bottle. To keep warm he made a suit of sandbags and slept at night on a bed of sandbags on a spoil truck, winding his watch before going to sleep. Each day he crawled to the collapse to listen for sounds of rescuers, but when they finally broke in he did not hear them. He was taken to the shaft bottom on a mine stretcher placed on a spoil truck by the medical officer and rested for two hours before climbing the shaft. Bedson was sent home and spent ten days in hospital and one month convalescing and was later discharged. The gallery was repaired and branched and mines of 41,150lbs and 32,850lbs were placed beneath the German salient at the end of July and mid-August 1916.³² When the Germans reflected on the behaviour of the debris after their blows at Petit Bois on 10 June they concluded that the British must be in the clay levels and that their charges had broken the clay over the British galleries, allowing the wet running sand to pour down into their galleries. They further concluded from the evidence of British deep mining at Petit Bois that if they had broken the covering of clay over their galleries then the British might go even deeper to prevent this occurring again. Therefore it was essential that they forestall the British before they could reclaim their galleries.

To the right of Petit Bois, two shafts were sunk by 250 Company late in 1916 from Maedelstede Farm. They ran two long drives parallel for about 670ft then branched: one to place a mine 2,600ft away in the Bois de Wytschaete, the other beneath the front line. The Germans blew several heavy camouflets in the area and work was delayed as the miners were withdrawn from the face for about three hours each day, presumably the Germans’ favoured times for blowing. The first gallery was driven 1,600ft but was halted when it became clear that it would not reach its objective. The second gallery was charged with 94,000lbs and only completed on 6 June 1917, one day before the attack.³³ Bad ground gave particular trouble to a drive towards Peckham Farm, started in December 1915, with one shaft sunk to 65ft and a second to 70ft. At 1,145ft it was beneath the objective and was charged with 87,000lbs. A branch was run off to a second objective but collapsed with an inrush of sand and water, which almost buried the men at the face. A second drive broken out to the right also had to be abandoned, but a third found good clay and was driven to a point just before the German support line until the ground again gave way. Several small chambers were constructed with difficulty and a carefully waterproofed charge of 20,000lbs laid. The electric pumps broke down and the main gallery collapsed, cutting off both charges. The gallery had to be completely redug about 10ft above the old gallery for almost 1,000ft before rejoining the old tunnel. The detonator leads were reconnected in March 1917, but the smaller charge was too difficult to recover and was abandoned.³⁴

Spanbroekmolen was the first of the mines that Cropper started behind the British lines in December 1915 to get to the clay level. It took several attempts to sink a shaft to 60ft and 250 Company had run a gallery 90ft when it was taken over by 3rd Canadian Company in late January 1916. The Canadians advanced it 790ft and it was then taken over by 171 Tunnelling Company, who completed a 1,717ft run until it was beneath the powerful German position at Spanbroekmolen. At the end of June 1916 the charge of 91,000lbs of ammonal in 1,820 tins was complete, the largest yet laid by the British. With the postponement of the attack the British selected the additional objectives of two German strong points, Rag Point and Hop Point, 2,700ft and 3,500ft from the shaft. A branch from the Spanbroekmolen gallery was started and inclined down to 120ft depth. By mid-February 1917 the branch was driven 1,140ft and had passed beneath the German lines. The Germans had been attempting to sink but found that all their efforts with timber-lined shafts at Spanbroekmolen proved futile. They lined the shaft with concrete but even this came to a dead halt in the sand. Eventually, by February 1917, they had managed to sink two shafts in the salient and five to the south, where the British branch gallery crossed the German line. The Germans blew two camouflets, the first of which did little damage, but a second a week later smashed 500ft of the branch incline and some of the main gallery. The British decided to abandon the branch because an aggressive attempt to destroy the German shafts would further alert them to the presence of deep British mines in the area. On 3 March the Germans blew the British main gallery, probably with a 13,000kg camouflet laid from their Ewald shaft, leaving it beyond repair and resulting in it being cut off for three months. The British had to drive a new gallery alongside, which was cut in at 1,429ft. They placed a new priming charge of 1,000lbs of dynamite in contact with the original charge and the tamping was completed just a few hours before zero on 7 June:

One of the most dramatic incidents of the Battle of Messines was the receipt by the headquarters of the 36th Division of a pencilled note from Major H.M. Hudspeth, commanding 171 Coy, to the effect that it was ‘almost certain’ that the Spanbroekmolen mine would go up next morning.³⁵