Lecture 4.8: Mining

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22 févr. 2014 (il y a 3 années et 5 mois)

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Lecture 4.8
: Mining

Chapter 8


Question: How do rocks in the ground become the minerals & metals that you use each
day?


The Uneven Distribution of Mineral resources Has Social and Environmental
Consequences

Crustal abundance (fig 8.26)

Rocks

v
-

ores

Metals

Copper

Nickel

Copper

Aluminum

Minera
ls of interest are bound in ores like sulf
ides (FeS)

Nonmetal Ores

Sand

Clay

Salt

Phosphates

Countries go from expo
r
ters to importers of minerals (USA: Ni)

What metal comes from bauxite?

Mineral resources can be h
eld by private companies

Metal
Reserve
s

(Table 8.1)


Types of Mining

Surface

Strip mining

Mining spoils or tailings

Open Pit Mining (Kennecott Bingham Canyon Mine, UT.)

Mountaintop
removal

Placer Mining

(water)

Subsurface Mining

Coal, Diamonds Gold


EXTRACTION

PROCESSING (smelting)


Mining Legislation

Early mining
laws
promoted economic development

The General Mining Act (1872)

Surface Mining Control and R
eclamation Act (1977)

ENVIRO
NMENTAL IMPACTS OF MINING

Chapter 8


Question: What negative environmental consequences come from mining?


Ming Operations Cover Several Square Miles

Surface Mining Consequences

Habitat destruction

Erosion

Road construction

Damage to local waterways

Decreased Air Quality

Altering geography & topography
(Mountain Top Removal)

Sediments/Chemicals into Waterways

Cyanide & Hg

Acid Mine Drainage (AMD)


Mountaintop removal

Placer Mining

S
edimentation

Use of Mercury to attract gold

Subsurface Mining

They operate below the water table

Acid Mine Drainage

Land subsidence

VIDEO: The Toxic Rockies

(Human Impacts: Black Lung disease)

Reclamation

Restore the land its original Physical/Chemical/B
iological condition

Topsoil is physically stable

Water infiltration & retention

SMCRA OF 1977

Backfill

Contouring

Distribute topsoil

Replanted with native species

Trapper Mine in Craig, CO

Columbian sharp
-
tailed grouse

Elk

Mule deer

antelope