Instructor’s Manual for Environmental Science, 15th edition
Web Resources
US Geological Survey
USGS global mineral use report.
Digital Integration
Correlation to Global Environment Watch
Biotechnology
E-Waste
Global Geoscience Watch:
Geology
Mining
Mountaintop Removal
Mining
Correlation to Explore More
Chapter 12: Geology and Nonrenewable Minerals
Environmental Chemistry Nanotechnology
Suggested Answers to End of Chapter Questions
Answers will vary but these represent phrases from this chapter. The following are examples of the material
that should be contained in possible student answers to the end of chapter questions. They represent only a
summary overview and serve to highlight the core concepts that are addressed in the text. It should be
anticipated that the students will provide more in-depth and detailed responses to the questions depending
on an individual instructor’s stated expectations.
Review
CORE CASE STUDY
1. Explain the importance of the rare earth metals.
• The rare earth elements are extremely important for widely used modern technologies. China has
Section 12-1
2. What are the two key concepts for this section? Define geology, core, mantle, crust,
asthenosphere, and lithosphere. Define mineral, mineral resource, and rock. Define and distinguish
among sedimentary rock igneous rock, and metamorphic rock and give an example of each. Define the
rock cycle and explain its importance. Define ore and distinguish between a high-grade ore and a low-
grade ore. List five important nonrenewable mineral resources and their uses.
• CONCEPT 12.1A Dynamic processes within the earth and on its surface produce the mineral
resources we depend on.
• CONCEPT 12.1B Mineral resources are nonrenewable because they are produced and renewed
over millions of years largely by the earth’s rock cycle.
Instructor’s Manual for Environmental Science, 15th edition
Section 12-2
3. What are the two key concepts for this section? What are the reserves of a mineral resource and how can
they be expanded? What two factors determine the future supply of a nonrenewable mineral resource?
Explain how the supply of a nonrenewable mineral resource can be economically depleted and list the five
choices we have when this occurs. What is depletion time and what factors affect it?
• CONCEPT 12.2A Nonrenewable mineral resources exist in finite amounts and can become
economically depleted when it costs more than it is worth to find, extract, and process the
remaining deposits.
• CONCEPT 12.2B There are several ways to extend supplies of mineral resources, but each of
4. What five nations supply most of the world’s nonrenewable mineral resources? How dependent is the United
States on other countries for important nonrenewable mineral resources? Explain the concern over U.S.
access to rare earth mineral resources. Describe the conventional view of the relationship between the supply
of a mineral resource and its market price. Explain why some economists believe this relationship no longer
applies.
• Five nations—the United States, Canada, Russia, South Africa, and Australia—supply most of the
nonrenewable mineral resources used by modern societies.
• Since 1900, and especially since 1950, there has been a sharp rise in the total and per capita use of
mineral resources in the United States. According to the USGS, each person in the United States
uses an average of 22 metric tons (24 tons) of mineral resources per year. As a result, the United
5. Summarize the opportunities and limitations of expanding mineral supplies by mining lower-grade
ores. What are the advantages and disadvantages of biomining? Describe the opportunities and
possible problems that could result from deep-sea mining.
• Some analysts contend that we can increase supplies of a mineral by extracting lower grades of
ore. They point to the development of new earth-moving equipment, improved techniques for
removing impurities from ores, and other technological advances in mineral extraction and
processing. Such advancements have made it possible to extract some lower-grades ores and even
to reduce their costs.
• One way to improve mining technology is to use microorganisms to extract minerals in a process
called in-place, or in situ, mining. This biological approach, sometimes called biomining, removes
desired metals from ores through wells bored into the deposits. It leaves the surrounding
Section 12-3
6. What is the key concept for this section? Summarize the life cycle of a metal product.
7. What is surface mining? Define overburden and spoils. Define open-pit mining and strip mining, and
distinguish among area strip mining, contour strip mining, and mountaintop removal mining. Describe
three harmful environmental effects of surface mining. What is subsurface mining? Summarize the
harmful effects of gold mining. Define tailings and explain why they can be hazardous. What is
smelting and what are its major harmful environmental effects?
Instructor’s Manual for Environmental Science, 15th edition
• Shallow mineral deposits are removed by surface mining, in which materials lying over a deposit
are removed to expose the resource for processing.
• Overburden is the soil and rock overlying a useful mineral deposit. It is usually set aside in piles of
waste material, called spoils.
• In open-pit mining, machines dig very large holes and remove ores, sand, gravel, and stone such
as limestone and marble.
• Deep deposits of minerals are removed by subsurface mining, in which mineral resources are
removed from underground through tunnels and shafts. It is used to remove coal and metal ores
that are too deep to be extracted by surface mining.
• Mercury is a highly toxic chemical that interferes with the human nervous system and brain
functions, and it can build up to high levels in the human body. Mercury is used illegally and
rampantly in Asia, Africa, and Latin America by tens of thousands of small-scale gold miners who
use it to separate gold from stream sediments, especially in the South American country of
Columbia. Many miners and villagers in these illegal mining areas suffer from deadly mercury
poisoning. Fish populations in one area of Borneo have dropped by 70%, due to this form of
pollution. As many as 3 grams of mercury escape to the environment for every 1 gram of gold
produced in this way. It is the second-biggest human-related source of mercury pollution in the
world after the burning of coal.
Chapter 12: Geology and Nonrenewable Minerals
Section 12-4
8. What is the key concept for this section? Give two examples of promising substitutes for key mineral
resources. What is nanotechnology and what are some of its potential environmental and other benefits?
What are some problems that could arise from the widespread use of nanotechnology? Describe the potential
of using graphene as a new resource. Explain the benefits of recycling and reusing valuable metals. List five
ways to use nonrenewable mineral resources more sustainably. What are two examples of research into
substitutes for rare earth metals? Explain why uneven distribution of lithium among various countries is a
concern.
• CONCEPT 12.4 We can try to find substitutes for scarce resources, reduce resource waste, and
recycle and reuse minerals.
• Some analysts believe that even if supplies of key minerals become too expensive or too scarce
due to unsustainable use, human ingenuity will find substitutes. They point to the current materials
• See Science Focus: The Nanotechnology Revolution.
o Nanotechnology, or tiny tech, uses science and engineering to manipulate and create
materials out of atoms and molecules at the ultra-small scale of less than 100 nanometers.
o Scientists plan to use atoms of abundant substances such as carbon, silicon, silver,
titanium, and boron as building blocks to create everything from medicines and solar
cells to automobile bodies.
• A sustainable way to use nonrenewable mineral resources (especially valuable or scarce metals
such as gold, iron, copper, aluminum, and platinum) is to recycle or reuse them. Recycling has a
much lower environmental impact than that of mining and processing metals from ores. Cleaning
up and reusing items instead of melting and reprocessing them has an even lower environmental
impact.
Section 12-5
9. What is the key concept for this section? What are tectonic plates, and what typically happens when they
collide, move apart, or grind against one another? Define volcano and describe the nature and major effects
of a volcanic eruption. Define earthquake and describe its nature and major effects. What is a tsunami and
what are its major effects?
Instructor’s Manual for Environmental Science, 15th edition
• CONCEPT 12.5 Dynamic processes move matter within the earth and on its surface and can cause
volcanic eruptions, earthquakes, tsunamis, erosion, and landslides.
• Tectonic plates are huge rigid plates that move extremely slowly atop the asthenosphere.
• Tectonic plates can also slide and grind past one another along a fracture (fault) in the lithosphere.
• Forces inside the earth’s mantle and near its surface push, deform, and stress rocks. At some point
the stress can cause the rocks to suddenly shift or break and produce a transform fault, or fracture,
in the earth’s crust. When a fault forms, or when there is abrupt movement on an existing fault,
energy that has accumulated over time is released in the form of vibrations, called seismic waves,
which move in all directions through the surrounding rock. This internal geological process is
called an earthquake. Most earthquakes occur at the boundaries of tectonic plates when colliding
plates create tremendous pressures in the earth’s crust or when plates slide past one another at
transform faults. Relief of the earth’s internal stress releases energy as shock (seismic) waves,
which move outward from the earthquake’s focus like ripples in a pool of water. Scientists
measure the severity of an earthquake by the magnitude of its seismic waves.
10. What are the three big ideas of this chapter? Explain how we can apply the three scientific principles of
sustainability can be applied to obtain and use rare earth metals and other nonrenewable mineral
resources in more sustainable ways.
• The chapter’s three big ideas:
o Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks, form
deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis.
Chapter 12: Geology and Nonrenewable Minerals
Critical Thinking
1. Give three reasons why rare earth metals (Core Case Study) are important to your lifestyle..
2. Would you favor giving the owners of the California rare earth metals mine significant government tax
breaks and subsidies to put the mine back into full production? Explain. Would you favor reducing the
environmental regulations for the mining and processing of these metals? Explain.
3. You are an igneous rock. Describe what you experience as you move through the rock cycle. Repeat this
exercise, assuming you are a sedimentary rock and again assuming you are a metamorphic rock.
• As an igneous rock, I begin my journey deep below the surface of the earth in a hot and molten state
called magma. As I move up through the upper mantle, I cool and harden and form granite. I can also
take another turn on my journey, and if I erupt out of the earth, rather than cool beneath it, I become lava
4. What are three ways in which you benefit from the rock cycle?
5. Use the second law of thermodynamics (see Chapter 2) to analyze the scientific and economic
feasibility of each of the following processes:
a. Extracting certain minerals from seawater
b. Mining increasingly lower-grade deposits of minerals
Instructor’s Manual for Environmental Science, 15th edition
6. Suppose you were told that mining deep-ocean mineral resources would mean severely degrading
ocean bottom habitats and life forms such as giant tubeworms and giant clams. Do you think that such
information should be used to prevent ocean bottom mining? Explain
• Student answers will vary, but one point of view is:
o Some analysts say that seafloor mining is less environmentally harmful than mining on
land. However, marine biologists are concerned that the sediment stirred up by such
7. List three ways in which a nanotechnology revolution could benefit you and three ways in which it
could harm you. Do you think the benefits outweigh the harms? Explain.
Three positive ways that nanotechnology could benefit me would be that soil, air, and groundwater
could be cleaned of industrial pollutants. Another positive effect would be an affordable way to purify
8. What are three ways to reduce the harmful environmental impacts of the mining and processing of
nonrenewable mineral resources? What are three aspects of your lifestyle that contribute to these harmful
impacts?
(2) Find substitutes for, or go without, scarce materials.
(3) Reduce waste
Global Environment Watch Exercise
Use the Global Environment Watch site to find and read an article that deals with U.S. rare earth metal
supplies (Core Case Study). Summarize the conclusions expressed in the article. Is there scientific
information cited in the article to support the author’s conclusions? Give specific examples. Do you
Chapter 12: Geology and Nonrenewable Minerals
Rare earth elements are critical to many existing and emerging 21st century applications including clean–
energy technologies such as hybrid cars and electric vehicles; high-technology applications including cell
phones and digital music players; hard disk drives used in computers; microphones; fiber optics; lasers; and
in addition, critical defense applications such as global positioning systems, radar and sonar; and advanced
water treatment applications, including those for industrial, military, homeland security, domestic and
foreign aid use. Current United States Geological Survey (USGS), the Department of Energy (DOE) and the
Government Accountability Office (GAO) reports show that U.S. Rare Earths, Inc. owns the mineral rights
to one of the major deposits of rare earth elements (REE) in the United States.
Data Analysis
1. Given that current worldwide usage of uranium is about 66,500 metric tons per year, how long will the
world’s present recoverable uranium resources last?
2. Assume U.S. usage is about 25% of world usage. If the United States were to rely only on its domestic
uranium resources, how long would they last, assuming a 100% recovery rate (meaning that 100% of
the resource can be used)?
3. Assume that most U.S. ore bodies contain high-grade ore (2% U) and that recovery rates of uranium
from the ore (accounting for losses in mining, extraction, and refining) average 65%. How many
metric tons of ore will have to be mined to meet U.S. needs?
In order to meet U.S. needs of 16,625 metric tons/year with ore of 2% U and 65% recovery rate, nearly