Geologic Resources
Chapter 15
General Mining Law 1872
Encouraged mineral exploration
Help develop the West – selling land
Mining provides – jobs, resources,
stimulation of economy
Environmentalist want – lease not
ownership, pay royalty, clean up
Resources
Metallic – nickel, iron, gold, aluminum
Nonmetallic – salt, gypsum, clay, soil
Energy – coal, oil, natural gas, uranium
Ore – rock containing a metallic mineral
Reserve – known deposit of mineral
that can be extracted for a profit
Resources in the ocean
Black smokers – hydrothermal vents
that deposit minerals in tall chimneylike
stacks
Manganese nodules – found on the
ocean floor, they contain 30-40%
manganese and other important
minerals
Black smoker
White
smoker
Sulfide
deposit
Magma
Tube worms
White crab
White clam
Fig. 14.3, p. 322
Removing mineral resources
Shallow deposits are removed through
surface mining
Open-pit mining
Dredging
Area strip mining
Contour strip mining
Deep deposits through subsurface
mining
Contour Strip Mining
Fig. 14.4d, p. 324
Area Strip Mining
Fig. 14.4c, p. 324
Dredging
Fig. 14.4b, p. 324
Open Pit Mine
Fig. 14.4a, p. 324
Room-and-pillar
Fig. 14.5b, p. 325
Underground Coal Mine
Fig. 14.5a, p. 325
Longwall Mining of Coal
Fig. 14.5c, p. 325
Mining
Overburden is removed to expose mineral,
disposed of as spoil
Surface mining accounts for about 90% of
non fuel mining and 60% of coal
Surface Mining Control and Reclamation Act
1977 – companies had to restore most of the
surface to pre-mining conditions
Environmental effects of mining
Scarring and disruption of land surface
Collapse and subsiding of land
Wind and water caused toxin-laced mining
wastes
Acid mine drainage
Sulfuric acid from rain water combination
Run-off to streams
Destroys aquatic life
Toxic chemical emission into air
Subsurface
Mine Opening
Surface Mine
Runoff of
sediment
Acid drainage from
reaction of mineral
or ore with water
Spoil banks
Percolation to groundwater
Leaching of toxic metals
and other compounds
from mine spoil
Leaching
may carry
acids into
soil and
ground
water
supplies
Fig. 14.7, p. 326
Steps
Mining
exploration, extraction
Processing
transportation, purification,
manufacturing
Use
transportation or transmission
to individual user,
eventual use, and discarding
Environmental Effects
Disturbed land; mining accidents;
health hazards; mine waste dumping;
oil spills and blowouts; noise;
ugliness; heat
Solid wastes; radioactive material;
air, water, and soil pollution;
noise; safety and health
hazards; ugliness; heat
Noise; ugliness
thermal water pollution;
pollution of air, water, and soil;
solid and radioactive wastes;
safety and health hazards; heat
Fig. 14.6, p. 326
After mining
Ore contains desired metal and waste
called gangue
Removed gangue is piled into heaps
called tailings
Smelting is then used to separate the
metal minerals
Smelting
Smelters create a large quantity of air
pollution
They also produce liquid and solid hazardous
waste that must be disposed
Companies are trying to reduce pollution,
lower costs, and decrease liability
How much is there?
Depletion time is the time it takes to
use up 80% of the reserve (profitable)
Reserve to production ratio – how long
will the known reserves last at current
rates of production
A
Mine, use, throw away;
no new discoveries;
rising prices
Recycle; increase reserves
by improved mining
technology, higher prices,
and new discoveries
Production
B
Recycle, reuse, reduce
consumption; increase
reserves by improved
mining technology,
higher prices, and
new discoveries
C
Present
Depletion
time A
Depletion
time B
Time
Depletion
time C
Fig. 14.9, p. 329
The big three
US, Germany, and Russia
Only 8% of the population
Use 75% of the most common metals
US uses 25% of the fossil fuels (cars)
Fig. 14.10, p. 329
Ocean mining
Will the ocean supply us with enough
minerals?
They are there, but too expensive
currently
Energy resources
99% of energy used to heat the earth
and all the buildings comes from the
sun
The sun also creates renewable energy
resources – wind, flowing water,
biomass
The rest
The last 1% comes from fuel resources
Fossil fuels make up the vast majority
Petroleum, coal, and natural gas
A small portion also comes from nuclear
sources
Oil and Natural Gas
Floating oil drilling
platform
Oil drilling
platform
on legs
Gas well
Oil storage
Oil well
Valves
Pipeline
Pump
Impervious rock
Natural gas
Oil
Water
Coal
Geothermal Energy
Hot water
Contour
storage
strip mining
Geothermal
power plant
Area strip
Pipeline
mining
Drilling
Mined coal
tower
Water
penetrates
Underground
coal mine
down
Water is heated
through
and brought up
the
as dry steam or
rock
wet steam
Coal seam
Hot rock
Water
Magma
Fig. 14.11, p. 332
Shifts in energy usage worldwide
During the 20th century
Coal use dropped from 55 to 22%
Oil increased from 2 to 30%
Natural gas rose from 1 to 23%
Nuclear rose from 0 to 6%
Renewable (wood and water ) dropped
from 42 to 19%
Way to go US
The U.S. is the world’s largest energy
consumer
We use 25% of the world’s energy (even
though we only have 4.5% of the total
population)
India with 17% of the population only uses
3% of the world’s commercial energy
91% of the U.S.’s energy in nonrenewable
Energy
Net energy refers to the amount of useful
energy minus the energy needed to find,
extract, process, concentrate, and transport
to the users
Nuclear energy has a low net energy ratio
because it is expensive to extract and process
uranium, convert it into a fuel, build and
operate the plant, and dismantle and deal
with radioactive plants and waste
Oil, Oil everywhere and not a
drop to drink
Extracted as crude oil or petroleum, a
thick liquid consisting of hydrocarbons,
and some sulfur, oxygen and nitrogen
impurities
Produced from decayed plant and
animal material over millions of years
Oil continued
Normally crude oil is not found in
underground pools, but is spread out in
the pores and cracks within rock deep
beneath the ground
Primary recovery – drill a hole and
pump out the light weight crude that
fills the hole
Oil continued
Secondary recovery – pumping water
into the well to force oil out of the
pores
The oil and water mixture is separated
after pumping
Only about 35% of the oil is removed
by primary and secondary recovery
Oil continued
Tertiary recovery – either a heated gas
or a liquid detergent is pumped into the
well to help remove more oil
Tertiary is expensive
Oil continued
At the refinery oil is converted into
petrochemicals and used as a resource to
create industrial organic chemicals,
pesticides, plastics, synthetic fibers, paints,
medicines and more.
OPEC – organization of petroleum exporting
countries control 67% of the worlds oil and
maintain control over pricing
Gases
Gasoline
Aviation fuel
Heating oil
Heated
crude oil
Diesel oil
Naphtha
Furnace
Grease
and wax
Asphalt
Fig. 14.16, p. 337
Advantages
Ample supply for
42–93 years
Low cost (with
huge subsidies)
High net
energy yield
Easily transported
within and
between countries
Low land use
Disadvantages
Need to find
substitute within
50 years
Artificially low
price encourages
waste and
discourages
search for
alternatives
Air pollution
when burned
Releases CO2
when burned
Moderate water
pollution
Fig. 14.21, p. 340
Oil continued
Oil shale is a fine grained sedimentary rock
containing solid combustible organic material
called kerogen
Shale oil is made from heating oil shale
Tar sand contains bitumen another
combustible organic material
Both are more expensive than crude recovery
Advantages
Moderate existing
supplies
Large potential
supplies
Disadvantages
High costs
Low net energy
yield
Large amount of
water needed to
process
Severe land
disruption from
surface mining
Water pollution
from mining
residues
Air pollution
when burned
CO2 emissions
when burned
Fig. 14.25, p. 342
Natural Gas
Mostly CH4 methane with some ethane,
propane and butane and small amounts
of hydrogen sulfide (toxic)
LPG (liquefied petroleum gas) the
propane and butane are removed from
natural gas and stored under pressure
How long will it last?
Natural gas should last about 125 years
worldwide
About 75 years in the US
Overall about 200-300 years with rising
prices, better technology, and more
discoveries
Advantages
Disadvantages
Ample supplies
(125 years)
Releases CO2
when burned
High net energy
yield
Methane
(a greenhouse
gas) can leak
from pipelines
Low cost (with
huge subsidies)
Less air pollution
than other
fossil fuels
Lower CO2
emissions than
other fossil fuels
Shipped across
ocean as highly
explosive LNG
Sometimes
burned off and
wasted at wells
because of low
price
Moderate environmental impact
Easily transported
by pipeline
Low land use
Good fuel for
fuel cells and
gas turbines
Fig. 14.26, p. 342
The future of power plants
There is currently being developed a
combined cycle natural gas electric
power plant with 60% efficiency
This is much better than 32-40%
efficiency of others (coal, oil, nuke)
What other reasons make it better?
Coal
Solid fuel of combustible carbon, most
formed 285-360 million years ago
Peat – 1st, low heat content
Lignite – 2nd, low heat and low sulfur
Bituminous Coal – 3rd, high heat and
abundant supply, high sulfur
Anthracite – 4th, high heat, low sulfur,
limited supply
Increasing heat and carbon content
Increasing moisture content
Peat
(not a coal)
Lignite
(brown coal)
Bituminous Coal
(soft coal)
Anthracite
(hard coal)
Heat
Heat
Heat
Pressure
Pressure
Pressure
Partially decayed
plant matter in swamps
and bogs; low heat
content
Low heat content;
low sulfur content;
limited supplies in
most areas
Extensively used
as a fuel because
of its high heat content
and large supplies;
normally has a
high sulfur content
Highly desirable fuel
because of its high
heat content and
low sulfur content;
supplies are limited
in most areas
Fig. 14.27, p. 344
Coal for energy
Coal provides about 22% of the
commercial energy in the world
It is used to create 62% of the worlds
electricity
75% of the worlds steel
China is the largest user followed by US
US creates 52% of energy with coal
Advantages
Ample supplies
(225–900 years)
High net energy
yield
Low cost (with
huge subsidies)
Disadvantages
Very high
environmental
impact
Severe land
disturbance, air
pollution, and
water pollution
High land use
(including mining)
Severe threat to
human health
High CO2
emissions
when burned
Releases
radioactive
particles and
mercury into air
Fig. 14.28, p. 344
The cost of coal
Land disturbance
Air pollution (especially sulfur dioxide)
Co2 emissions
Water pollution
Electricity production (coal) is the second
largest producer of toxic emissions
The most deadly emission is mercury
Wonderful coal
60,000 babies annually are born with brain
damage due to mercury exposure, typically
from pregnant mothers eating mercury in fish
Coal also releases more radioactive particles
into the atmosphere than nuclear power
plants
Also, acid rain and methane release
Coal in the US
Air pollutants kill thousands (estimates
are from 60,000 – 200,000)
Cause at least 50,000 cases of
respiratory disease
Cost several billion dollars in property
damage
The good news
Fluidized bed combustion is reducing
the amount of pollution
Hot air is blown under a mix of crushed
limestone and coal while it is burnt
This removes most sulfur dioxide,
reduces Nox and burns the coal more
efficiently and cheaply
Flue gases
Coal
Limestone
Steam
Fluidized bed
Water
Air nozzles
Air
Calcium sulfate
and ash
Fig. 14.29, p. 345
Coal gasification
Solid coal can be converted into
synthetic natural gas (SNG)
It can also be made into synfuels
(liquids) through coal liquefaction
Neither is expected to play a major role
in our future energy needs
Raw coal
Remove dust,
tar, water, sulfur
Air or
oxygen
Raw gases
Steam
2C + O2
Coal
Pulverizer
CO + 3H2
2CO
CH4 + H2O
Methane
(natural gas)
Recover
sulfur
Clean
Methane
gas
Recycle unreacted
carbon (char)
Slag removal
Pulverized coal
Fig. 14.30, p. 345
Advantages
Disadvantages
Large potential
supply
Low to moderate
net energy yield
Vehicle fuel
Higher cost than
coal
High
environmental
impact
Increased surface
mining of coal
High water use
Higher CO2
emissions than
coal
Fig. 14.31, p. 346
Nuclear Energy
Uranium 235 and plutonium 239 are
split (nucleus) to release energy
The reaction rate is controlled
The energy heats water and turns it to
steam
Steam spins turbines connected to
generators which create electricity
LWR light water reactors
All US reactors are of this type, so know
it
Small amounts of Radioactive gases
Uranium fuel input
(reactor core)
Containment shell
Waste heat
Emergency core
Cooling system
Electrical power
Steam
Control
rods
Turbine
Heat
exchanger
Hot coolant
Useful energy
25 to 30%
Generator
Hot water output
Condenser
Pump
Pump
Coolant
Cool water input
Black
Moderator
Water
Pump
Waste
heat
Coolant
passage
Pressure
vessel
Shielding
Periodic removal
and storage of
radioactive wastes
and spent fuel assemblies
Periodic removal
and storage of
radioactive liquid wastes
Waste
Water source
heat
(river, lake, ocean)
Fig. 14.32, p. 346
Nuclear is out of favor
The US has not ordered a new nuclear
facility since 1978, and 120 ordered
since 1973 were cancelled
Most countries are phasing out nuclear
plants or are not continuing to expand
their programs, except China who is
trying to move away from dependence
on coal
Why is nuclear not meeting
expectations?
Multi-billion dollar cost of construction
Strict govt. safety regulations
High operating costs
More malfunctions than expected
Poor management
Public concern after Chernobyl, and Three
Mile Island
Investor concern about economic feasibility
Advantages
Large fuel
supply
Disadvantages
High cost (even
with large
subsidies)
Low
environmental
impact (without
accidents)
Low net
energy yield
Emits 1/6 as
much CO2 as coal
High
environmental
impact (with major
accidents)
Moderate land
disruption and
water pollution
(without
accidents)
Catastrophic
accidents can
happen
(Chernobyl)
Moderate land use
Low risk of
accidents
because of
multiple
safety systems
(except in 35
poorly designed
and run reactors
in former Soviet
Union and
Eastern Europe)
No acceptable
solution for
long-term storage
of radioactive
wastes and
decommissioning
worn-out plants
Spreads
knowledge and
technology for
building nuclear
weapons
Fig. 14.35, p. 349
Coal
Ample supply
High net energy
yield
Very high air
pollution
High CO2
emissions
65,000 to 200,000
deaths per year
in U.S.
High land
disruption from
surface mining
High land use
Low cost (with
huge subsidies)
Nuclear
Ample supply
of uranium
Low net energy
yield
Low air pollution
(mostly from fuel
reprocessing)
Low CO2
emissions
(mostly from fuel
reprocessing)
About 6,000
deaths per
year in U.S.
Much lower land
disruption from
surface mining
Moderate land
use
High cost (with
huge subsidies)
Fig. 14.36, p. 349
Chernobyl
In the former Soviet Union, April 26, 1986 the
reactor core went out of control and exploded
sending a cloud of radioactive dust into the
atmosphere
3,576 – 32,000 people died
400,000 forced to evacuate
62,000 square miles still contaminated
More than 500,000 people exposed to high
level radiation
Cost the govt. $385 billion
Three Mile Island
March 29, 1979 in Harrisburg, Penn.
Coolant failed and core melted
Radioactive material escaped into air
50,000 people evacuated
Luckily the radiation release was
believed to be too low to cause death
or cancer
Cleanup has cost $1.2 billion so far
What do we do with the waste?
Low level radioactive waste must be stored
for 100-500 years until it reaches a safe level
(does not give off harmful ionizing radiation)
This was done by sealing the waste in steel
drums and dumping it in the ocean
Today some countries (US) stores the waste
at govt. run landfills, but no one wants to live
anywhere near them
Waste container
2 meters wide
2–5 meters high
Several
steel drums
holding waste
Steel wall
Fig. 14.38a, p. 351
Steel wall
Lead shielding
Up to 60
deep trenches
dug into clay.
As many as 20
flatbed trucks
deliver waste
containers daily.
Barrels are stacked
and surrounded
with sand. Covering
is mounded to aid
rain runoff.
Clay bottom
Fig. 14.38b, p. 351
And the bad stuff?
High level radioactive waste must be
stored for 10,000 to 240,000 years until
it reaches a safe level
Currently most is stored at the reactor
site, sealed in drums, in pools of water
Proposed methods of disposal
Bury deep underground – this is the leading
strategy currently
Shoot it into space/Sun
Bury it deep in the Antarctic ice sheet
Dump it into descending subduction zones
Bury in deep mud deposits on ocean floor
Convert into less harmful isotopes (currently
we do not have the technology)
Storage Containers
Fuel rod
Personnel elevator
2,500 ft.
(760 m)
deep
Primary canister
Air shaft
Nuclear waste shaft
Overpack container
sealed
Fig. 14.39b, p. 352
Fig. 14.39c, p. 352
Slide 52
Slide 53
Fig.
Radioactive contamination
The EPA suggests that there are 45,000
sites in the US (20,000 belong to the
DOE)
It is expected to cost over $230 billion
over the next 75 years
More than 144 highly contaminated
weapons construction sites will never be
completely cleaned