If the coal deposit is more broken up, the surface mine is called an open pit. Most Albertan coal is mined with strip mines. Most of British Columbia's coal is mined with open-pit mines. Coal is also mined underground with shafts that tunnel deep under the surface. Corridors lead sideways from the shafts to reach the coal.
Underground mining is necessary when the coal is too deep or hard to reach for surface mining.
Some underground mines are many kilometres long. In Nova Scotia, they extend under the ocean. Underground mines are more expensive and more dangerous to miners. How we use coal For thousands of years, small amounts of coal were burned to heat buildings and cook food. During the 1800s and early 1900s, coal became more widely used.