For the British offensive on 1 July no attacks were made across the crater fields of the Tambour or Bois Français. The German positions on the surface around Fricourt were extremely strong and the village itself was like a fortress. As with 179 Company at La Boisselle, 178 Company was unable to place mines under the village itself. Instead, 178 placed three mines 90ft beneath the Tambour position, increasing in size from north to south, of 9,000, 15,000 and 25,000lbs. These were to form overlapping craters along the whole position, burying the German front line, collapsing dugouts and blocking enfilade fire against the 21st Division attacking north of the Tambour. The mines were also detonated two minutes before zero, at 7.28am, but the larger mine failed to explode and was found to have become damp.³⁵ The shock effect of the mines may have protected the first two companies of the 10th West Yorkshire Regiment, which attacked immediately to the north of the Tambour, but when the second two crossed no man’s land German machine gunners opened a devastating fire. The worst machine-gun fire came from the northern edge of the Tambour and continued in action for most of the morning. The machine gunners had survived the mines and may well have used the lips to gain a better field of fire. The two companies were ‘practically annihilated and lay shot down in their waves’,³⁶ the battalion suffering 710 casualties, the worst of any on 1 July 1916. The failure of the largest and most southerly mine to detonate will have had some impact on the ability of the Germans to defend, and meant that the 7th Division to the south also suffered from enfilade fire.

Two gaps in the British 7th Division attack were left south of Fricourt owing to the mine craters in no man’s land, at Bois Français and Kiel Trench. A series of 500lb mines were blown in the latter area but the gaps in the attack increased losses to the attacker. Despite the very heavy casualties of the assaulting troops, advances on either side of the village rendered the German hold untenable and they withdrew during the night. Mining cannot be said to have made a major contribution to the fall of Fricourt and its legacy in the form of bands of cratered and impassable no man’s land favoured the defenders.

The village of Mametz, assaulted by the right battalions of the 7th Division, although attended by heavy losses, was markedly more successful than the attacks to the north. Furthermore, the attacks of the 18th and 30th Divisions and the French to their right achieved all of their objectives on 1 July. A series of mines of between 200 and 2,000lbs were placed under strong points or at the end of Russian saps (see Chapter 9). The sector of the eastern part of the 7th Division and the 18th Division was that of 183 Company, commanded by Hickling since his posting from 172 Company at St Eloi in early 1915. He was asked to prepare a series of Russian saps for the attack, to be used to reinforce the captured positions and from the ends of which small mines were blown. In view of the work required, he would have to drop defensive mining, which guaranteed the underground safety of the British front-line trenches at Carnoy and Fricourt only up to 1 July. He halted all deep mining except what he called ‘camouflage work’ to give the impression of continuing activity. He seems not to have had deep drives ready beneath key points in the German lines. Instead he drove shallow tunnels across, the ends of which were filled with small charges except for two larger mines, at Bulgar Point (2,000lbs) and Casino Point (5,000lbs). At Casino Point it was necessary to incline the tunnel down as it neared the German lines, to gain the necessary depth to lay the charge. As the chalk grew harder the method of softening involved drilling holes with a carpenter’s auger, into which they poured vinegar. The heading was only just completed and charged in time for the attack.³⁷

The mine at Bulgar Point failed to explode, owing to a British mortar projectile cutting the leads shortly before zero.³⁸ The Casino Point mine, designed to destroy flanking machine guns and dugouts, was fired a few seconds before 7.27am and produced a crater with lips 97ft in diameter and 30ft deep. Hickling reported that three dugouts and four sniper’s posts were buried and he suspected a machine-gun emplacement.³⁹ The infantry of the 6th Royal Berkshires attacked from 200yds away and suffered casualties from the mine debris, but also seem to have derived benefit from it.

Hickling took a calculated risk by abandoning deep mining prior to the 1 July attack. His men surveyed the German mining systems in the captured areas and discovered an inclined gallery running beneath the Kiel Trench crater field, which reached 200ft in depth. They estimated that to form a crater it would require a charge of 450,000lbs and the resulting crater would have had a diameter of 460ft.⁴⁰

Following the 1 July attack there were few mines blown during the Somme fighting. In the south, the front moved on from the mine systems. At High Wood, 178 Company drove a mine at just 25ft depth, 320ft long, which they charged with 3,000lbs. It was blown thirty seconds before zero on 3 September 1916. British infantry occupied the crater, but lost it to counterattacks. The gallery was reopened by 178 Company, charged again with the same quantity and blown on 9 September, and this time it was held.⁴¹ In the north of the Somme battlefield, the Beaumont Hamel mine gallery was reopened by 252 Company four days after 1 July in preparation for a repeat mining attack on Hawthorn Ridge. The tunnel had to be re-driven and they completed charging with 30,000lbs of ammonal on 30 October. The attack of the Battle of the Ancre was launched on 13 November. This time there was no delay between the launch of the infantry attack and the blowing of the mine. The infantry moved forward to get clear of their own wire six minutes before zero, which was at 5.45am. The mine itself was used to signal zero and coincided with the opening crash of the British barrage. Infantry of the 51st Highland Division overran the crater and 252 Company found 58 Germans alive in a dugout adjacent to the crater. They told them that six other dugouts holding a similar number of men were destroyed by the explosion.⁴² The Battle of the Somme closed later in November.

The second blowing of the Hawthorn mine was the point at which the British learnt how to use mines correctly in the attack. Mines were not part of a step-by step process, but a valuable shock weapon, which was nevertheless local and short-lived. Assault had to follow immediately, while the lighter debris was still falling, and before enemy troops on the flanks could gain the crater lips for their own advantage. Casualties from falling debris were minimal and were preferable to losing the race to the lips. The lessons of the Hohenzollern and St Eloi mining attacks of March 1916 were not incorporated into the attack plans of the opening of the Battle of the Somme. For Harvey the key lesson was to blow at zero. Other lessons concerned the location of mines, which were not always well-placed, in great part due to the virtual impossibility of silent working in chalk. The reforms in mining command and control introduced at the beginning of 1916 had only some bearing on the Somme, where local commanders were able to overrule the advice of the Inspector of Mines’ staff. In particular Preedy, the Controller of Mines of the 4th Army, lacked the authority to overrule senior officers commanding or on the staffs, especially Hunter-Weston and Fuller, who were both also Sappers. The Somme was the arena in which the British learnt the tactical methods of using the potential advantage offered by offensive mining. Mines could not, however, solve the tactical problems of the Somme, where the objectives were too deep for the capacity of the artillery. British attack tactics concentrated increasingly on coordinating artillery with the infantry advance, and on turning German defensive tactics against themselves. Mining, however, was still to play a major role in British offensives in the first half of 1917.