The crater itself was caused by two charges of ammonal, of 24,000lb and 30,000lb.

It was blown along with 16 others at 0728 on the morning of 1 July 1916 as a two-minute precursor to the start of the offensive.  The Lochnagar Crater measured 300ft across and 90ft deep (200ft wide and 81ft deep by... From NEN Gallery