CHAPTER 19 MINERAL RESOURCES

NO STONE UNTURNED

A bevy of unfamiliar minerals are crucial for our everyday technologies—but they come

with a slew of problems.

NO STONE UNTURNEDA bevy of unfamiliar minerals are crucial for our everyday technologies

—but they come with a slew of problems.19

Main Concept

Society relies on many mineral resources. Concerns range from limited supply, to the dangers posed to people and environment, to unsustainability. Less destructive methods of extraction and more environmental safeguards are needed.

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Learning Outcomes

At the end of this chapter, you will know:• How geologic forces shape the

planet, rocks, and minerals on Earth• What mineral resources society

uses and how those resources are mined and processed

• The environmental and social impacts of mining/processing and how the negative impacts can be reduced

NO STONE UNTURNEDA bevy of unfamiliar minerals are crucial for our everyday technologies

—but they come with a slew of problems.

19 NO STONE UNTURNEDA bevy of unfamiliar minerals are crucial for our everyday technologies

—but they come with a slew of problems.

Background: Most people do not realize the number or amount of nonrenewable minerals used by society. They are rare, expensive, and the extraction and processing can cause a great deal of environmental damage. The increase in electronics has exacerbated the problem.

People like Dr. Mark Hersam are working on developing less expensive and less environmentally damaging alternatives to many minerals.

19 NO STONE UNTURNEDA bevy of unfamiliar minerals are crucial for our everyday technologies

—but they come with a slew of problems.

While the term mineral refers to any solid chemical material with a regular structure, it is often used in conjunction with materials that have an economic value.

Rare earth minerals are a group of 17 economically valuable minerals that may not technically be rare in nature, but they are not evenly distributed across the surface and may be hard to find or process.

Metals are minerals that are generally malleable and are often conductive.

TERMS TO KNOW:MineralsRare earth mineralsMetal

19 NO STONE UNTURNEDA bevy of unfamiliar minerals are crucial for our everyday technologies

—but they come with a slew of problems.

Society relies on many mineral resources, some more familiar than others. Most of our modern conveniences would not exist without minerals.

Geologic processes produce mineral resources.19

Geologic processes produce mineral resources.19

Accessible minerals are in the crust and lithosphere. The deepest mines are barely 5% of the depth of the lithosphere.

Geologic processes can bring material from the upper mantle to the surface.

Geologic processes produce mineral resources.19TERMS TO KNOW:GeologyTectonic platesElements

The lithosphere is divided into many separate plates that float on the asthenosphere. The movement of plates away from each other exposes magma to rise and cool. In other areas, one plate dives under another and becomes part of the asthenosphere. Volcanic activity can release new material onto the surface as well. Elements are recombined to form new compounds.

Geologic processes produce mineral resources.19TERM TO KNOW:Rock

Minerals are the basic units of rock. Rock contains mixtures of minerals that must be collected, extracted, and processed.

Geologic processes produce mineral resources.19TERM TO KNOW:Rock cycle

Igneous rock forms from cooling magma. Metamorphic rock is transformed by heat and pressure.Sedimentary rocks forms by deposition and pressure.

The three classes of rock are interchangeable by various weathering effects.

Geologic processes produce mineral resources.19TERMS TO KNOW:OreMining

Metal minerals abundant enough to be economically viable when mined are called ores.

Although formed by the earth, the rate is so slow that minerals are considered nonrenewable resources.

Use of mineral resources has increased dramatically in recent decades. More than 50% of all minerals ever mined have been used between 1975 and 2000, and more than 97.5% of the copper ever mined was after 1900.

Extracting and processing mineral resources impacts the environment.19

When ore is relatively close to the surface and in a shallow, horizontal deposit, strip mining is often used.

The overburden is removed, the ore extracted, and the overburden replaced. Revegetation and restoration is needed.

Coal mines frequently are of this type.

Extracting and processing mineral resources impacts the environment.19

Ore deposits that tend to be very deep require open-pit mining.

The mine pit is dug out in benches, or shelves, and heavy equipment is used to haul out tons of ore. This equipment is so large that it is often shipped to the mine in pieces and assembled on location.

Metal ores such as copper are mined this way.

Extracting and processing mineral resources impacts the environment.19

Heavy metals in sedimentary materials are recovered using placer mining techniques.

Sediment-laden material is drawn from the water and through a sluice. Heavier materials settle to the bottom, as the water and lighter material is washed away.

Gold is mined this way.

Extracting and processing mineral resources impacts the environment.19

Ore deposits that tend to be deep underground require subsurface mining.

Shafts and tunnels burrow into the mountains and deep underground. Fresh air, power, and light must be brought into the tunnels. Ore is dug out and moved to the surface.

Many gemstones are mined this way.

Extracting and processing mineral resources impacts the environment.19

In addition to the initial impacts due to removal of the surface material (such as road building and vegetation loss), there are impacts in the processing of the ore:

Waste rock, which often contains contaminants and other hazardous wastes

Air pollution from the smelting process

Energy and resources needed to move, operate, and power heavy equipment

Extracting and processing mineral resources impacts the environment.19

Extracting and processing mineral resources impacts the environment.19

Extracting and processing mineral resources impacts the environment.19

Mining also comes with significant social consequences.19

Mining also comes with significant social consequences.19

Mining also comes with significant social consequences.19

We can minimize the impacts of mining through better conservation strategies.19

TERM TO KNOW:E-wasteOne advantage to mineral resources is that, while not renewable, they are almost completely reusable. Mineral resources can be removed from old products and recycled to make new ones, whether the same, such as aluminum cans, or different, such as rubber from old tires being used as playground padding.

Plastics and metals can be reclaimed from old equipment and used to make new items.

We can minimize the impacts of mining through better conservation strategies.19

Mining of aluminum ore is costly, takes a significant amount of energy, and produces a great deal of waste. As a nonrenewable resource, the supply is limited. Transportation and packaging industries use significant amounts of aluminum products and need a steady supply.

Recycling current supplies can and does significantly reduce the need and demand for new raw materials. Cash deposits and redemption refunds have significantly increased recycling rates in the United States.

We can minimize the impacts of mining through better conservation strategies.19

We can minimize the impacts of mining through better conservation strategies.19

Improved mining technology allows for more efficiency and higher yields from the same amount of ore, thus reducing the total amount of material that needs to be processed. As the value increases, more deposits become economically viable. For example, many previously abandoned gold and silver mines in the western United States are being re-opened.

With the increase in value, the previously abandoned sites are again economically productive. And the impact is reduced since it is an established site rather than a new mine.

We can minimize the impacts of mining through better conservation strategies.19

Extracting and processing minerals from waste materials reduces the need for new material. Recycling of economically and technologically important rare earths and metals can also reduce the need to import these resources from other parts of the world.

We can minimize the impacts of mining through better conservation strategies.19Many people in the United States and other more-developed countries live a “throw away” lifestyle. Rather than wait until an item naturally expires, they acquire the newest and most modern model or item as soon as they can. This not only increases the demand for raw materials, but also ties up resources often left in drawers or other places.

We can minimize the impacts of mining through better conservation strategies.19

Efficiency is important not only in the collection of mineral resources, but in their use as well. Carbon is less expensive and more readily available than minerals used in electronics.

Fiber-optic cables can carry more data than the same size copper wire, so there is less physical material needed for the same job as well as being less expensive.

PERSONAL CHOICES THAT HELP19

UNDERSTANDING THE ISSUE19

UNDERSTANDING THE ISSUE19

ANALYZING THE SCIENCE19

EVALUATING NEW INFORMATION19

MAKING CONNECTIONS19