Cape Breton’s TNT

Cape Breton coal was essential to the war effort in WWI as a fuel and an ingredient in steel. However, it made another, little-known contribution to the Allies’ victory – providing the key element for the explosive, TNT.

TNT is short for trinitrotoluol (aka trinitrotoluene), which is produced from the waste gases of coke ovens. In other words, it is a by-product of steelmaking.

Steel is mainly iron and carbon, and the carbon is derived from metallurgical coal, which contains more carbon, less ash and less moisture than thermal coal.

To produce steel, metallurgical coal is heated to over 1000 degrees Celsius in the absence of oxygen. Without oxygen, the coal does not burn; instead it begins to melt.

The coal is then quickly cooled in water or air to produce a hard, porous brick of carbon known as coke. The coke is fed into a blast furnace with iron ore and a handful of other ingredients to make molten iron, which is then mixed (alloyed) with other metals to make many types of steel.

About 770 kilograms of metallurgical coal makes 600 kilograms of coke, which in turn produces one tonne of steel using a basic oxygen furnace.

This is the process that produces about 74% of the approximately 1.8 billion tonnes of steel the world produces each year. The balance comes mostly from recycling.

Much of Nova Scotia’s steel production during WWI was used to produce shell casings by companies such as the Nova Scotia Steel and Coal Company which made them at the Trenton steel works (

However, Britain needed not just empty shell casings but the TNT that made shells into weapons.

To help fulfill this need, the Dominion Steel Corporation, which ran the Sydney steel mill, decided to build a plant to capture the trinitrotoluol generated in its steelmaking process. According to Brian Douglas Tennyson’s “Nova Scotia at War, 1914–1919,” Dominion got inventor Thomas Edison who was, at the time, installing such a plant at a steel mill in Pennsylvania, to visit Sydney and offer guidance. The plant, the first in Canada, was completed within 60 days.

The Government of Canada gave Dominion a contract in February 1915 and production began in April. The trinitrotoluol produced at the Sydney steel mill was shipped to the Canadian Explosives Company in Beloeil, Quebec, where it was converted into the explosive used in shells.

By the end of the war, Dominion had produced over three million litres of trinitrotoluol, which was converted into 41.8 million pounds of TNT.

The February 1, 1916, edition of the Canadian Mining Journal contained an article called “Canadian Shell Making” which said Canadian manufacturers had produced three million shells by that time, even though Canada had not had shell production capacity prior to the war.

According to the Canadian War Museum, almost one-third of all British shells were being manufactured in Canada by 1917.

Nova Scotia coal helped make that possible by providing power, steel and TNT.

Nova Scotia’s coal and steel companies struggled throughout the war to keep production going as miners left the mines and steel mills to join the military. According to a 1916 article in the Canadian Mining Journal by Francis W. Gray, an English mining engineer who had immigrated to Cape Breton, “the drain upon the industry has been a severe one. The drop in production has assumed very serious proportions and, as the writer forecast a few months ago, the question of recruiting among miners is resolving into a choice between men and munitions.”

The Nova Scotia Steel and Coal Company and the Dominion Coal Company combined had lost 2,500 men to the military, according to Gray. While those soldiers were an important contribution to the war effort, it impacted steel and coal production, which were also essential to fighting the war. Gray wrote, “It must be admitted that the coal is as necessary to our final victory as any other munition. One might go further and say it is more necessary because coal is the foundation of all manufacturing activity.”

TNT was first discovered in 1863 by German chemist Julius Wilbrand, who saw it not as an explosive, but as a dye because of its yellow colour. Its potential as an explosive was not discovered until 1891 because it is relatively stable and safe to handle. Its low melting point – 80 degrees Celsius – also meant that it could be poured into shells in liquid form, which facilitated manufacturing.

The German military started using TNT as its standard explosive in 1902. However, in 1910, the British still did not consider it an explosive for manufacturing and storage purposes and exempted it from the UK's Explosives Act – the British still saw it mainly as a dye.

This gave the German military an advantage in the early days of WWI because TNT-filled shells are less likely to detonate on impact and more likely to penetrate armour before exploding. In contrast, British shells filled with the more sensitive picric acid did not penetrate armour, but exploded on contact, causing less damage.