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Coal and the Environment: Land and Air
Although abundant and cost-effective, coal has some
environmental challenges to overcome.Coal has a reputation as a
dirty fuel source, one that can pollute the air and damage
thelandscape.
So that coal might live up to its potential as a significant
source of energy, the coal industry isworking hard to ensure that
the mining and use of coal does not permanently damage land
orpollute air. The coal industry restores mined land to its
original condition or prepares it for moreproductive uses, and it
has incorporated technological advances to keep the air clean and
safe.Reclaiming LandIn the past, coal mining often left behind
landscapes that were unattractive and unproductive.
Animals and plant life that once thrived in an area could no
longer survive in conditions producedby coal mining. Today, thanks
to land reclamation, it can be difficult to tell the difference
betweenland that has been mined and land that has not.Land
reclamation is the process of protecting, restoring, or improving
land before, during, andaftersurface mining. This means that the
land is preserved, nature is protected, and water and
soil are conserved. Ultimately, the land can become productive
farmland, be restored to forest, orundergo development as a
lake.How does this work?First, geologists study rock formations to
find possible coal reserves. Test holes are drilled so thatsamples
of coal can be examined for evidence of quality, quantity, and
location beneath thesurface.Then, the reclamation plan is made.
This involves studying the area's geology, plants, water, soil,and
wildlife. Information is recorded so that potential problems during
the mining process can beidentified and so that conditions may be
restored after the mining has been completed. Inaddition, the
mining site is examined for artifacts from past cultures. If any
are found, they areremoved and preserved.Next, the timeline for
mining and reclamation is set. The coal mining company works with
federaland state government agencies and local officials to ensure
that all regulations are beingfollowed.Once the planning phase has
been completed and the required permits obtained, mining maybegin.
The topsoil, subsoil, earth, and rock are removed and set aside,
and the coal that lies justbelow the surface is mined.During the
mining process, water is tested to ensure that it is not polluted.
If water is found to becontaminated, it is treated before it leaves
the mine area.Finally, the area is refilled with the overburden
(the earth and rock that were removed) and soils.
To the extent possible, the area is restored to its original
condition or improved. This often meansplanting, seeding, and
irrigating the landa process completed over many years.Reducing Air
PollutionWhen coal is burned, it releases impurities such as
sulfur, nitrogen, and fly ash. These canpollute the air or
contribute to conditions that can lead to "acid rain,"
precipitation that damagesforests and pollutes rivers and lakes.
Today, though, advances in technology mean that about 99percent of
the chemicals that can pollute the air and more than 95 percent of
the chemicals thatcan cause acid rain are removed.
http://www.teachcoal.org/glossary.html#coalhttp://www.teachcoal.org/glossary.html#land_reclamationhttp://www.teachcoal.org/glossary.html#surface_mininghttp://www.teachcoal.org/aboutcoal/articles/coalamer.htmlhttp://www.teachcoal.org/glossary.html#overburdenhttp://www.teachcoal.org/glossary.html#fly_ashhttp://www.teachcoal.org/glossary.html#coalhttp://www.teachcoal.org/glossary.html#land_reclamationhttp://www.teachcoal.org/glossary.html#surface_mininghttp://www.teachcoal.org/aboutcoal/articles/coalamer.htmlhttp://www.teachcoal.org/glossary.html#overburdenhttp://www.teachcoal.org/glossary.html#fly_ash
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These technological advances are part of an effort referred to
as the Clean Coal Technology(CCT) Program, which began in 1985.
Since that time, the federal government has contributedmore than $2
billion toward this program to make the burning of coal cleaner and
safer. The coalindustry has contributed more than $4 billion toward
this goal.How is coal made cleaner?There are several ways. Coal can
be crushed and washed before it is burned. The washingprocess often
goes a long way in removing harmful sulfur, but it does not remove
all of the sulfur.While the coal burns, special combustion
processes can remove more sulfur and nitrogen.Devices called flue
gas desulfurization systems, or "scrubbers," remove more than 90
percent ofthe sulfur dioxide emissions from the burning process.
The flue gas is sprayed with a mixture ofwater and lime or
limestone, which reacts with the sulfur dioxide to form a wet
sludge or, in somecases, a dry powder that can be disposed of or
made into pellets for roadbeds or intoplasterboard or concrete
blocks.
Another method for tackling air pollution involves using devices
called electrostatic precipitators,which give coal dust particles
an electric charge so they can be attracted to a collector
plate.
Other methods of removing pollutants involve the way the coal is
actually burned. In fluidized bedcombustion (FBC), coal is inserted
into a bed of particles (including limestone) that aresuspended in
the air and react with the coal to heat the boiler more cleanly. In
FBC, coal isburned at a slightly lower temperature, which helps
prevent some nitrogen oxide gases fromforming. The result is that
FBC can remove more than 90 percent of the sulfur and nitrogen
whilethe coal is burning. Through a chemical reaction, sulfur gases
are changed into a dry powdercalled calcium sulfate, which can be
used to make wallboard for building homes.The coal gasification
method changes coal into a gas that has the same heating value as
naturalgas. Coal gas burns cleaner than coal because so many
pollutants have been removed duringthe transformation to a gas.
This method can remove up to 99.9 percent of the sulfur and tiny
dirtparticles from burning coal. For more information about coal
gasification, go to:
http://www.eastman.com/Company/Gasification/Overview.htm.
http://www.fossil.energy.gov/programs/powersystems/cleancoal/http://www.fossil.energy.gov/programs/powersystems/cleancoal/http://www.teachcoal.org/glossary.html#flue_gas_desulfurization_systemhttp://www.teachcoal.org/glossary.html#fluehttp://www.teachcoal.org/glossary.html#sludgehttp://www.teachcoal.org/glossary.html#electrostatic_precipitatorhttp://www.teachcoal.org/glossary.html#FBChttp://www.teachcoal.org/glossary.html#FBChttp://www.acaa-usa.org/2005_CCP_Production_and_Use_Figures_Released_by_ACAA.pdfhttp://www.teachcoal.org/glossary.html#coal_gasificationhttp://www.eastman.com/Company/Gasification/Overview.htmhttp://www.fossil.energy.gov/programs/powersystems/cleancoal/http://www.fossil.energy.gov/programs/powersystems/cleancoal/http://www.teachcoal.org/glossary.html#flue_gas_desulfurization_systemhttp://www.teachcoal.org/glossary.html#fluehttp://www.teachcoal.org/glossary.html#sludgehttp://www.teachcoal.org/glossary.html#electrostatic_precipitatorhttp://www.teachcoal.org/glossary.html#FBChttp://www.teachcoal.org/glossary.html#FBChttp://www.acaa-usa.org/2005_CCP_Production_and_Use_Figures_Released_by_ACAA.pdfhttp://www.teachcoal.org/glossary.html#coal_gasificationhttp://www.eastman.com/Company/Gasification/Overview.htm
