Explosion of the mine beneath Hawthorn Redoubt. Note: This is NOT a photo of the Lochnagar Mine which was not photographed at the time.
Debris was flung almost a mile into the air, as graphically recorded by Royal Flying Corps pilot Cecil Lewis in his superb book 'Sagittarius Rising'
"At La Boisselle the whole earth heaved and flashed, a tremendous and magnificent column rose up into the sky. There was an ear-splitting roar, drowning all the guns, flinging the machine sideways in the repercussing air. The earth column rose, higher and higher to almost 4,000 feet. There it hung, or seemed to hang, for a moment in the air, like the silhouette of some great cypress tree, then fell away in a widening cone of dust and debris."
When the main attack began at 7:30 am, the Grimsby Chums Pals Battalion successfully occupied the crater and began to fortify the eastern lip which now dominated the surrounding ground. However elsewhere the attack at La Boisselle went badly and infantry sought shelter in the crater, particular those who had been attacking up Sausage Valley to the south of the village. The prominent crater drew fire, including from British artillery although eventually it was learnt it contained sheltering infantry and the British shell fire ceased.
In eight successive waves the infantrymen of the 34th Division stood up from their trenches, and in the straight lines prescribed, officers in front as ordered, set off at a walk to attack the German front line trenches.
The slaughter was immense, the German machine guns cut down the British infantry like a farmer's scythe cuts hay. Within minutes German artillery was raining down on the attacking survivors, the regimental rows of British soldiers had disappeared.