Lesson 13.2 Mining
More than a ton of waste may remain
after extracting just a few hundredths
of an ounce of gold.
Lesson 13.2 Mining
What Is Mined?
•
Ores: Groups of minerals that are mined so metal or
metals can be removed
•
Nonmetallic minerals: Minerals, including gemstones,
that as a whole have valuable properties
•
Fuels: Minerals that can be used to generate energy
Did You Know? About 100 minerals
are considered gemstones, including
diamond, topaz, and jade.
Lesson 13.2 Mining
Process of Mining and Mineral Use
From initial exploration to disposal, mining and mineral use
involve many steps.
Lesson 13.2 Mining
Mining Methods
• Surface mining
• Strip mining
• Open pit mining
• Mountaintop removal
• Solution mining
• Placer mining
• Undersea mining
• Subsurface mining
Did You Know? Some subsurface mines in
South Africa extend 4 km underground.
A strip mining operation in Wyoming
Lesson 13.2 Mining
Strip Mining
• The practice of mining a seam of mineral, by first removing a
long strip of overlying soil and rock
• Strip mining is only practical when the ore body is relatively
near the surface.
• There are two forms of strip mining: area stripping and contour
stripping.
• Area Stripping: used on fairly flat terrain to extract deposits
over a large area.
• Contour Stripping: used in hilly terrain where the ore deposit
usually follows the contour of the land.
Lesson 13.2 Mining
Strip Mining
Lesson 13.2 Mining
Subsurface Mining
• Digging tunnels or shafts into the Earth to reach ore
deposits
• Ore, for processing, and waste rock, for disposal, are
brought to the surface through the tunnels and shafts.
Lesson 13.2 Mining
Subsurface Mining
Lesson 13.2 Mining
Open Pit Mining
• A method of extracting ore from the Earth by its removal from
a large pit
• Different than strip mining because it goes down deeper into
the Earth,
Ore
Ore
Strip Mining
Open Pit
Lesson 13.2 Mining
Open Pit Mining
• Lavender Mine, Bisbee AZ
Lesson 13.2 Mining
Mountaintop Removal
• Involves the mining of the top of a mountain.
• Entire ore bodies are extracted from a mountain, hill, or ridge
by removing the land above the seams, usually through
explosives.
• The land is dumped back on the ridge and compacted to
reflect the original shape of the mountain
Lesson 13.2 Mining
Mountaintop Removal
Lesson 13.2 Mining
Solution mining
• Used to recover minerals such as copper and uranium
through boreholes drilled into a deposit
• The process initially involves drilling of holes into the ore
deposit. Explosives are then used to create open
pathways in the deposit for solution to penetrate.
• A solution is pumped into the deposit where it makes
contact with the ore.
• The solution bearing the dissolved ore content is then
pumped to the surface and processed.
Lesson 13.2 Mining
Solution mining
Lesson 13.2 Mining
Placer Mining
• This type of mining takes valuable minerals from the
sediments put down by rivers
• Rivers erode the land, taking out valuable minerals while
they do so
• Sediment rich water is then placed through a filtration
system, where the valuable minerals are kept and the rest
put back into the river
Lesson 13.2 Mining
Placer Mining
Lesson 13.2 Mining
Undersea Mining
• Large machines suck or scoop up large amounts of sand
and gravel from the sea floor
• The gravel and sand is then processed to extract valuable
minerals
• More concentrated mineral deposits can be found and
gathered from hydrothermal vents
• It is not very cost effective, and thus has been largely
unsuccessful
Lesson 13.2 Mining
Undersea Mining
Lesson 13.2 Mining
Processing Ore
• Ores must be processed to gain access to the metals they
contain. This occurs in three stages
• Breakdown of the ore
• Separation from the ore
• Metal production
Lesson 13.2 Mining
Breakdown of Ore
• Ore is crushed and ground into tiny pieces
• Particles must be small enough to properly separate the
different minerals from each other
Lesson 13.2 Mining
Separation of Ore
• Crushed ore is separated into metals and tailings
• Tailings: the waste product and unwanted particles
• Several methods of ore separation. The most common is
froth flotation
• In this method, chemicals are added to the ground up
ore to make the desired minerals float on top of water
• Once they float, they can be easily separated
Lesson 13.2 Mining
Metal Production
• Once the ore has been separated, metals can be produced
by smelting
• In smelting, crushed ore is put into a furnace and heated to
its melting point
• Once it is melted, the impurities separate from the ore,
giving the pure quantities of the metal desired
Lesson 13.2 Mining
Processing Ore