The Hawthorn Ridge mine was the northern-most of the ten mines detonated on 1 July and one of the three large mines, the other two being the Lochnagar mine and the Y Sap mine at La Boisselle. The mine contained about 40,000 lb (18 long tons) of explosives. The plan was to detonate all other mines at 7:28 am, two minutes before Zero hour when the infantry advance would begin, but Lieutenant-General Aylmer Hunter-Weston, whose VIII Corps was holding the Hawthorn Ridge sector, favoured blowing the mine hours before the main attack, believing this would give his 29th Division time to capture and consolidate the crater. However, the Fourth Army commander, Lieutenant-General Henry Rawlinson rejected this proposal on the grounds that the Germans would probably take possession of the crater. In this stance he was supported by General Sir Douglas Haig, commander of the British Expeditionary Force. As a compromise, Hunter-Weston was allowed to blow the mine ten minutes before Zero, rather than two minutes.
One witness to the detonation of the Hawthorn Ridge mine was British cinematographer Geoffrey Malins who was filming the 29th Division's attack. He had his camera set up about half a mile away, trained on the ridge and waiting for the explosion.
The ground where I stood gave a mighty convulsion. It rocked and swayed. I gripped hold of my tripod to steady myself. Then for all the world like a gigantic sponge, the earth rose high in the air to the height of hundreds of feet. Higher and higher it rose, and with a horrible grinding roar the earth settles back upon itself, leaving in its place a mountain of smoke.