Transcript Chapter 16 Nonrenewable Mineral Resources – Part 2 Key Questions    What are nonrenewable mineral resources and how are they formed? How do we find and.

Chapter 16
Nonrenewable Mineral
Resources – Part 2
Key Questions
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What are nonrenewable mineral resources
and how are they formed?
How do we find and extract nonrenewable
mineral and energy resources from the
earth’s crust?
How fast are mineral supplies being used
up?
What are Mineral Resources?
 Concentration
of naturally occurring
material in or on the earth’s crust
that can be extracted and processed
into useful materials
 Classified as nonrenewable resources
because they take so long to produce
 We know how to find and extract
100+ nonrenewable minerals from
the earth’s crust
We can extract…
 Metallic
mineral resources (iron,
copper, aluminum)
 Nonmetallic mineral resources (salt,
clay, sand, phosphates, soil)
 Energy resources (coal, oil, natural
gas, uranium)
Ore
 Rock
containing enough of 1+
metallic minerals to be mined for
profit
 We convert 40 metals extracted from
ores into everyday items that are
either 1) used and thrown away OR
2) reused or recycled
Categories of nonrenewable
mineral resources
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1.
2.
3.
4.
US Geological Survey divides nonrenewable
mineral resource into categories:
Identified resources: deposits of nonrenewable
mineral resource with a known location and
quantity
Undiscovered resources: potential supplies
assumed to exist in theory
Reserves: identified resources from which
resource can be extracted for profit
Other resources: identified and discovered but
not classified as reserves
How do ores form from magma?
 Ores
form as a result of internal and
external geologic processes
 Plate tectonics shape the earth’s
crust and determine where the
richest mineral deposits are found
As magma cools, it
crystallizes into mineralcontaining igneous rocks
Ore deposits form through
hydrothermal processes
Upwelling magma solidifies
into black smokers
Shoots out mineral-rich hot
water on the seafloor
Minerals accumulate as hot
and cold water contact
Form ore deposits rich in
copper, lead, zinc, silver, and
gold
Finding nonrenewable resources
Aerial photos and satellite images
 Planes that detect deposits of radioactive
metals
 Gravimeter to measure differences in
density (ore differs from surrounding rock)
 Drilling deep well and extracting core
samples
 Seismic surveys by explosions and
analyzing shock waves
 Chemical analysis of water and plants
(absorb minerals)
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Mining techniques (once resources
have been found)
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Surface mining: equipment strips outer layer of
soil and rock; in US, used to extract 90% nonfuel
resources and 60% coal
Open-pit mining: machines dig holes and remove
ores
Dredging: chains scrape underwater mineral
deposits
Area strip mining: parallel strips made in flat
land; power shovels used
Contour strip mining: terraces cut into side of
hill; power shovels used
Mountaintop removal: explosives used to remove
top of mountain and expose coal underneath
Open Pit Mine
Dredging
Area Strip Mining
Contour Strip Mining
Surface Mining Control and
Reclamation Act of 1977
 Requires
mining companies to
restore surface-mined land so that it
is usable again
 Although surface-mined land can be
restored, it is expensive and not
done in many countries
Subsurface mining
 Used
to remove coal and other metal
ores that are too deep to be
extracted by surface mining
 Blast tunnels to get to deposit, use
machinery to transport ore to the
surface
 Disturbs 1/10 as much land as
surface mining, produces less waste
 More dangerous and expensive
Environmental Effects of Extracting
Mineral Resources
Fig. 15-6 p. 343
Subsurface
Mine Opening
Acid drainage from
reaction of mineral
or ore with water
Percolation to groundwater
Surface Mine
Runoff of
sediment
Spoil banks
Leaching of toxic metals
and other compounds
from mine spoil
Acid mine drainage-pollution and degradation
by acid runoff and toxic chemicals from mining
-can kill fish and other aquatic life
Leaching
may carry
acids into
soil and
groundwater
supplies
Smelting
Melting
metal
Separation
of ore from
machine
Conversion
to product
Metal ore
Recycling
Surface
mining
Discarding
of product
Scattered in environment
Processes involved in extraction
 Smelting:
used to separate metal
from other elements in the ore
 Enormous amount of pollution which
damages surrounding vegetation and
soil
 Smelters also produce liquid and
hazardous waste that must be
disposed of safely
Are there environmental limits?
 Resource
experts believe that the
greatest danger from increasing
consumption of nonrenewable
resources is environmental damage
caused by extraction and processing.
 More accessible and high-grade ores
are exploited first
 It takes more $ to exploit the deeper
ores, causing more environmental
effects
Will there be enough mineral
resources?
 Future
of nonrenewable minerals
depends on: actual supply and rate
at which supply is used
 Economic depletion: cost more to
find, extract, transport and process
than it’s worth
 Depletion time: time it takes to use
up a certain proportion of NM
Supplies of mineral resources
 Reserve-to-production
ratio: number
of years that reserves of a NM will
last
 Materials revolution: new materials
(ceramics and plastics) are being
developed as replacements for
metals
 Substitutes cannot be found for
many mineral resources