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. A new use was as a fuel to power steam locomotives. Coal also provided an oil called kerosene for lighting and a gas called methane for heating. Coal was processed to yield complex chemical products such as fertilizers, dyes, explosives and plastics.