Developed in Germany before WWI, Ammonal was originally a mixture of Ammonium Nitrate, aluminum, and charcoal. Later, TNT was put into the mix to allow for greater ease of detonation and the explosive became widely used as a commercial product. It was used by both sides during the war at various formulations and continued in use, to a lesser extent, in World War II. Adopted by the British during World War I to stretch out available supplies of TNT, Ammonal is essentially Amatol with an admixture of powdered aluminum. It was used as a general demolition explosive by all sides during WWI, One of the largest intentional, non-nuclear, man-made explosions took place during the Battle of Messines at 3:10 AM on 7 July, 1917. A series of mines, galleries dug under enemy lines, were detonated over a period of 20 seconds. The mines had been dug for several years starting in 1915. Of the 26 mines that had been dug by the British along Messines Ridge, 22 were fired in June, 1917. A total of 424,800 kilograms (936,524 pounds, or 418.09 long tons) of primarily military-grade (British Demolition) Ammonal were fired. One mine alone was 43,400 kilograms (95,681 pounds) of explosive. The blasts could be heard as far away as London and several universities recorded the incident as an earthquake. The craters remain visible today.
