Chapter 16

Question 1

Through _______________ _______________ , mining companies can identify areas where there is a high likelihood of finding valuable mineral resources in quantities that are worth mining.

Answer 1

mineral exploration

Question 2

Usually, a _______________ _______________ has 100 to 1,000 times the concentration of the mineral than ordinary rocks do and enough material to justify opening a mine.

Answer 2

mineral deposit

Question 3

Exploring rock for mineralization is the first step in finding an _______________ deposit.

Answer 3

ore

Question 4

Ore deposits that are usually found _______________ m or more beneath Earth’s surface are mined by using subsurface mining methods.

Answer 4

50

Question 5

A command method of subsurface mining that is used to extract coal and salt is known as _______________ -and-_______________ mining.

Answer 5

room-and-pillar

Question 6

A more efficient way to remove coal from a subsurface seam is to use a method called _______________ mining.

Answer 6

longwall

Question 7

In longwall mining, a machine called a _______________ moves back and forth across the face of a coal seam.

Answer 7

shearer

Question 8

For underground deposits of soluble mineral ores such as potash, salt, and sulfur, _______________ _______________ is an economical mining method.

Answer 8

solution mining

Question 9

_______________ mining methods are used when ore deposits are located close to Earth’s surface.

Answer 9

Surface

Question 10

_______________ - _______________ mining is a method that is often used to mine large quantities of near-surface ore. Coal and metals such as copper are mined using the _______________ - _______________ method.

Answer 10

open-pit

open-pit

Question 11

In an open-pit mine, the ore is mined _______________ layer by layer.

Answer 11

downward

Question 12

In the 19th-century American Midwest, horse- and mule-drawn plows were used to remove the rock, called _______________ , that covered near-surface coal seams. Today, some of the largest machines in the world are used to strip the _______________ that covers sallow coal deposits.

Answer 12

overburden

overburden

Question 13

Building stones such as _______________ and _______________ are mined in quarries.

Answer 13

granite

marble

Question 14

Sand, gravel, and crushed rock, known as _______________ , are the main products of quarrying.

Answer 14

aggregates

Question 15

The solar evaporation process consists of placing sea water, which is about _______________ percent sodium chloride, into enormous, shallow ponds.

Answer 15

2.7

Question 16

When the concentration of sodium chloride in the sea water reaches a little over _______________ percent, salt crystals begin to form. With further evaporation, layers of crystalline salt, or _______________ , build up.

Answer 16

25

halite

Question 17

When these layers reach the desired thickness, the salt is _______________ . Salt harvesting generally occurs _______________ .

Answer 17

harvested

once a year

Question 18

The solar evaporation process has been used to produce salt for _______________ of years. Today, solar evaporation is used largely in developing countries.

Answer 18

thousands

Question 19

About _______________ percent of the world’s salt comes from the solar evaporation process.

Answer 19

30

Question 20

When rock weathers and disintegrates, minerals within the rock are released. These minerals are concentrated by wind and water into surface depots called _______________ deposits.

Answer 20

placer

Question 21

In the process called _______________ , crushed ore is melted at high temperatures in furnaces to separate impurities from molten metal.

Answer 21

smelting

Question 22

In a furnace during the process of smelting, material called a _______________ bonds with impurities and separates them from the molten metal. The molten metal, which is desired, falls to the bottom of the furnace and is recovered. The flux and impurities, which are less dense, form a layer called _______________ on top of the molten metal.

Answer 22

flux

slag

Question 23

The ocean floor contains significant mineral resources, which include _______________ , precious metals such as _______________ and _______________ , mineral ores, and sand and gravel.

Answer 23

diamonds

gold and silver

Question 24

With an increase in U.S. energy requirements, particularly the demand for coal to fuel power plants that produce electricity, the scale of _______________ mining has grown.

Answer 24

surface

Question 25

Because of the environmental impacts of mining on such a large scale, mining has become one of the most _______________ _______________ industries in the United States.

Answer 25

heavily regulated

Question 26

There are many environmental impacts of mining. In the United States, the federal and state governments and mining companies are spending billions of dollars to clean up _______________ mines. Much of this legacy has been left to U.S. citizen from a time when there was little regulation of mining and mineral processing.

Answer 26

abandoned

Question 27

Surface mining can cause both _______________ pollution and _______________ pollution.

Answer 27

air

noise

Question 28

Noise is created by the equipment that is used in a mine as well as by _______________ . Whereas equipment noise may be a nuisance, _______________ can cause physical damage to nearby structures.

Answer 28

blasting

blasting

Question 29

Because of air and noise pollution, most surface mines are not located near _______________ populations.

Answer 29

urban

Question 30

Water resources can be _______________ impacted by mining.

Answer 30

negatively

Question 31

When these materials react with oxygen and water, they form dilute _______________ acid. This acid can dissolve toxic minerals that remain in mines and excess rock. The contaminated water that results from this process is known as acid mine drainage, or _______________ .

Answer 31

sulfuric

AMD

Question 32

Removing soil from a surface mine site strips away all plant life. With their natural habitat removed, _______________ will leave the area.

Answer 32

animals

Question 33

Dredging can negatively affect aquatic ecosystems and _______________ change the bottoms of rivers.

Answer 33

physically

Question 34

Dredging disturbs river bottoms and destroys _______________ plant life in the dredged portion of the river.

Answer 34

aquatic

Question 35

This disturbance of a riverbed can cause sediments to contaminate a river for up to _______________ km.

Answer 35

10

Question 36

Excess rock from mines is sometimes dumped into large piles called _______________ . Running water erodes unprotected dumps and transports sediments into nearby streams. The _______________ may harm water quality and aquatic life.

Answer 36

dumps

sediments

Question 37

Soil at a mine site is removed from the uppermost layer _______________ .

Answer 37

downward

Question 38

Minerals that contain sulfur may be found in deeper soil layers. If these minerals are exposed to water and oxygen in the atmosphere, chemical reactions result in the release of acid, which then acidifies the soil. When the acidified soil is returned to the mine site, it may be difficult for _______________ to grow.

Answer 38

plants

Question 39

The sinking of regions of the ground with little or no horizontal movement is called _______________ .

Answer 39

subsidence

Question 40

Subsidence occurs when _______________ that have been left standing in mines collapse or the mine roof or floor fails.

Answer 40

pillars

Question 41

_______________ , _______________ , _______________ , _______________ , _______________ _______________ , and _______________ that are built over abandoned mines could be damaged if the ground below them subsides.

Answer 41

Building
houses
roads
bridges
underground pipelines
utilities

Question 42

_______________ that start in underground coal seams are one of the most serious environmental consequences of coal mining.

Answer 42

Fires

Question 43

Lightning, forest fires, and burning trash can all cause _______________ - _______________ fires. In addition, fires can start by themselves when minerals in the coal that contain sulfur are exposed to oxygen.

Answer 43

coal-seam

Question 44

Coal mine fires are hard to put out and are often left to burn themselves out, which may take decades or even _______________ .

Answer 44

centuries

Question 45

A fire that has been burning through an underground coal seam in an Australian mountain is estimated to be _______________ years old.

Answer 45

2000

Question 46

Underground fires that burn their way to the surface release _______________ and _______________ that can cause respiratory problems.

Answer 46

smoke

gases

Question 47

_______________ on land in the United States are regulated by federal and state laws.

Answer 47

Mines

Question 48

The process of returning land to it is original or better condition after mining is completed is called _______________ .

Answer 48

reclamation

Question 49

As a requirement to obtain a mining permit, some states have _______________ forfeiture programs. In a bond forfeiture program, a mining company must post funds, called a bond, before a mining project begins. If the company does not mine and reclaim a site according to the standards required by its permits, the company must give these funds to the state. The state then uses the funds to reclaim the site.

Answer 49

bond

Question 50

States such as Pennsylvania have been large projects to reclaim abandoned mine lands. _______________ _______________ _______________ , _______________ _______________ , _______________ _______________ , and hazards related to open shafts and abandoned mining structures are all problems that these projects will attempt to correct.

Answer 50

Acid mine drainage
mine fires
mine subsidence