Download “Mining in Canada” (video)

“Mining in Canada” (video)
Global Geography 12
Rock containing an economic amount of mineral is called ore.
Two types of mining:
 Underground mining is expensive and is only used for rich ore bodies. It is
more dangerous due to the risk of collapse, floods or dangerous gases
such as methane
 Open pit mines are dug from the surface, as deep as 300 m. These are
cheaper than underground mines, but still expensive to operate!
The larger the machinery, the cheaper it is to handle each tonne of ore. This
makes mining require a lot of capital resources to be developed. It is also labour
intensive, and requires engineers and experts with technical knowledge. This
means it also requires human resources.
Refining is the process of getting the valuable mineral from the rock. There are
several ways pf separating ore from rock:
 In froth flotation, the mineral particles are floated on a froth in water to
separate them from heavier rock.
 Dense minerals, such as gold or tin or can be separated using gravity is
shaking tables or spinning helix cylinders.
 Some heavy metals are melted. The rock floats above the heavier metal
and is poured off.
 Some metals are dissolved from the rock. Gold mining sometimes uses a
cyanide solution.
Environmental Problems
After the minerals are separated from rock, they may need to go to a refinery to
be chemically changed into a useful form. Heating minerals (roasting) in air can
remove sulfur. The gases must then be treated to prevent acid rain.
Acid drainage is a problem caused by chemical reactions with the exposed
rock, air and water that creates sulfuric acid and heavy metals. The piles of
waste rock must be sloped and covered in clay to reduce water getting into the
rock. The acidic water that seeps through must be treated to remove the
metals. Not all waste rock causes this problem.
Heavy metals in waste water can also be a problem. Copper and nickel are
two minerals removed using a chemical reaction to create a sludge that settles
out.
The material removed from a mine must also be replaced or covered over. The
tailings (leftover rock) must be stabilized to prevent erosion, using drainage. The
process of restoring the environment is made faster by:
 replacing topsoil,
 planting cover crops, such as grasses,
 and restoring some of the soil microbes (like fungus).
Mining affects the local economy by buying equipment and services locally as
well as creating jobs within the mine.
Some mining towns can be affected by “Boom and bust” economic impacts if
only a single mineral is produced there. When the mine closes, or if the price of
the mineral goes down, jobs can be lost and the whole town suffers.