Lesson 13.2 Mining

More than a ton of waste may remain after extracting just a few hundredths of an ounce of gold.

What Is Mined?

Lesson 13.2 Mining

• 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.

Process of Mining and Mineral Use

Lesson 13.2 Mining

From initial exploration to disposal, mining and mineral use involve many steps.

Mining Methods

Lesson 13.2 Mining

• 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

Strip Mining

Lesson 13.2 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.

Strip Mining

Lesson 13.2 Mining

Subsurface Mining

Lesson 13.2 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.

Subsurface Mining

Lesson 13.2 Mining

Open Pit Mining

Lesson 13.2 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

Open Pit

Strip Mining

Open Pit Mining

Lesson 13.2 Mining

• Lavender Mine, Bisbee AZ

Mountaintop Removal

Lesson 13.2 Mining

• 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

Mountaintop Removal

Lesson 13.2 Mining

Solution mining

Lesson 13.2 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.

Solution mining

Lesson 13.2 Mining

Placer Mining

Lesson 13.2 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

Placer Mining

Lesson 13.2 Mining

Undersea Mining

Lesson 13.2 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

Undersea Mining

Lesson 13.2 Mining

Processing Ore

Lesson 13.2 Mining

• 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

Breakdown of Ore

Lesson 13.2 Mining

• Ore is crushed and ground into tiny pieces

• Particles must be small enough to properly separate the different minerals from each other

Separation of Ore

Lesson 13.2 Mining

• 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

Metal Production

Lesson 13.2 Mining

• 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

Processing Ore

Lesson 13.2 Mining