Chapter 16 Flashcards
Through _______________ _______________ , mining companies can identify areas where there is a high likelihood of finding valuable mineral resources in quantities that are worth mining.
mineral exploration
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.
mineral deposit
Exploring rock for mineralization is the first step in finding an _______________ deposit.
ore
Ore deposits that are usually found _______________ m or more beneath Earth’s surface are mined by using subsurface mining methods.
50
A command method of subsurface mining that is used to extract coal and salt is known as _______________ -and-_______________ mining.
room-and-pillar
A more efficient way to remove coal from a subsurface seam is to use a method called _______________ mining.
longwall
In longwall mining, a machine called a _______________ moves back and forth across the face of a coal seam.
shearer
For underground deposits of soluble mineral ores such as potash, salt, and sulfur, _______________ _______________ is an economical mining method.
solution mining
_______________ mining methods are used when ore deposits are located close to Earth’s surface.
Surface
_______________ - _______________ 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.
open-pit
open-pit
In an open-pit mine, the ore is mined _______________ layer by layer.
downward
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.
overburden
overburden
Building stones such as _______________ and _______________ are mined in quarries.
granite
marble
Sand, gravel, and crushed rock, known as _______________ , are the main products of quarrying.
aggregates
The solar evaporation process consists of placing sea water, which is about _______________ percent sodium chloride, into enormous, shallow ponds.
2.7
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.
25
halite
When these layers reach the desired thickness, the salt is _______________ . Salt harvesting generally occurs _______________ .
harvested
once a year
The solar evaporation process has been used to produce salt for _______________ of years. Today, solar evaporation is used largely in developing countries.
thousands
About _______________ percent of the world’s salt comes from the solar evaporation process.
30
When rock weathers and disintegrates, minerals within the rock are released. These minerals are concentrated by wind and water into surface depots called _______________ deposits.
placer
In the process called _______________ , crushed ore is melted at high temperatures in furnaces to separate impurities from molten metal.
smelting
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.
flux
slag
The ocean floor contains significant mineral resources, which include _______________ , precious metals such as _______________ and _______________ , mineral ores, and sand and gravel.
diamonds
gold and silver
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.
surface
Because of the environmental impacts of mining on such a large scale, mining has become one of the most _______________ _______________ industries in the United States.
heavily regulated
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.
abandoned
Surface mining can cause both _______________ pollution and _______________ pollution.
air
noise
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.
blasting
blasting
Because of air and noise pollution, most surface mines are not located near _______________ populations.
urban
Water resources can be _______________ impacted by mining.
negatively
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 _______________ .
sulfuric
AMD
Removing soil from a surface mine site strips away all plant life. With their natural habitat removed, _______________ will leave the area.
animals
Dredging can negatively affect aquatic ecosystems and _______________ change the bottoms of rivers.
physically
Dredging disturbs river bottoms and destroys _______________ plant life in the dredged portion of the river.
aquatic
This disturbance of a riverbed can cause sediments to contaminate a river for up to _______________ km.
10
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.
dumps
sediments
Soil at a mine site is removed from the uppermost layer _______________ .
downward
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.
plants
The sinking of regions of the ground with little or no horizontal movement is called _______________ .
subsidence
Subsidence occurs when _______________ that have been left standing in mines collapse or the mine roof or floor fails.
pillars
_______________ , _______________ , _______________ , _______________ , _______________ _______________ , and _______________ that are built over abandoned mines could be damaged if the ground below them subsides.
Building houses roads bridges underground pipelines utilities
_______________ that start in underground coal seams are one of the most serious environmental consequences of coal mining.
Fires
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.
coal-seam
Coal mine fires are hard to put out and are often left to burn themselves out, which may take decades or even _______________ .
centuries
A fire that has been burning through an underground coal seam in an Australian mountain is estimated to be _______________ years old.
2000
Underground fires that burn their way to the surface release _______________ and _______________ that can cause respiratory problems.
smoke
gases
_______________ on land in the United States are regulated by federal and state laws.
Mines
The process of returning land to it is original or better condition after mining is completed is called _______________ .
reclamation
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.
bond
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.
Acid mine drainage
mine fires
mine subsidence
