Metallurgical Coal

Minerals of Alberta

Folded coal with white layers from Lovettvile, Alberta

Folded thermal coal from Lovettville, Alberta, an abandoned coal mining village. Specimen is about 35 cm across.

Iridescent coal from Cadomin, Alberta

Fist-sized piece of iridescent high grade thermal coal from Cadomin, Alberta

Composition

The metallurgical coal mined in Alberta is bituminous in grade, and made of 60 - 80% carbon and differing amounts of air, water, nitrogen, hydrogen, and sulfur. Metallurgical coal is different from thermal coal that is burned to produce power. The thermal coal burned in Alberta is 35 - 45% carbon.

Age and Formation

Coal forms when thick layers of vegetation accumulated in bogs and swamps are buried, compacted, and heated through geologic time. As more heat and pressure are applied, over time, the carbon content increases, whereas the amount of other components, and water, decreases. The rise of the Rockies to the west influenced this process by providing a basin in which large amounts of vegetation could accumulate, a sediment source to cover the vegetation, and pressure and heat for the metamorphic processes. It’s not a coincidence that higher grade coals are found closer to the mountains than lower grade coals. Although coal in Alberta ranges in age from 65 - 145 million years old, the metallurgical coal mined in the province comes from layers 65 - 69 million years old and 106 - 125 million years old.

Important properties

Metallurgical coal is low in ash, sulfur, and moisture, and contains the right amount of hydrocarbons and plasticity.

Uses

Metallurgical coal is crushed and heated in an airless furnace at high temperatures around 1000 °C. The heat drives off the moisture, impurities, and sulfur. Meanwhile, the coal expands, becomes porous and turns into coke. Coke is heated with iron ore and lime (from limestone) in blast furnaces to make steel. Indigenous Peoples use coal to make carvings and makeup to wear during ceremonies. Metallurgical coal production is a growing industry in Alberta.

It’s a Fact!

By 2030, metallurgical coal will be the only coal mined in Alberta. The province is phasing out the use of thermal coal for the generation of electricity.