6. Environmental Impact
and Economics of Metal Ore Extraction and
mining–quarrying other minerals
What are the social, economic and
environmental impacts of exploiting metal ores (mineral extraction), of
using metals and of recycling metals – economic,
sociological and environmental issues
Metal ores are obtained
by mining/quarrying and that this involved digging up and processing
large amounts of rock.
Most ores are mined have
to be concentrated before the metal is extracted and purified.
This means that metal or mineral extraction
results in problems and issues in balancing ecological,
environmental, economic, social advantage factors.
It doesn't matter whether you are mining and
processing iron ore or limestone, many of the advantages and
disadvantages are common to these operations.
advantages of exploiting it's own mineral resources:
Useful products can
be made from metal to enhance our lives – most consumer products
we take for granted ie we expect to have them at our disposal.
revenue if the mineral or its products are exported.
people, especially new sources of employment in poor countries or areas of high
unemployment in developed countries.
go into the local/national economy leading to improvements in
schools, health service and transport etc.
Issues related to
local facilities promoted e.g. transport
systems, like roads, recreational and health social
disadvantages of exploitation of mineral resources and
reduction of its social and environmental impact:
mining–quarrying or processing can be reduced by air filter and
precipitation systems and even hosing water on dusty areas or
spoil heaps or carried away to somewhere else via tall chimneys.
Scarring of the
landscape from mining, quarrying, waste tips etc. as well as
loss of wildlife habitat.
process operation or transport of raw materials and products
can be reduced by cleaning the 'waste' or 'used' air, water and
waste gases etc. of
toxic or acidic materials e.g.
monoxide from the blast furnace extraction of iron, it can
be burnt as a fuel, but it must not be released into the air
unless converted to biologically harmless carbon dioxide.
dioxide gas from copper extraction of its sulphide ore is an
irritating poisonous gas which can also cause acid rain, but
it can be converted to the useful, therefore saleable,
industrial chemical concentrated sulphuric acid, so you can
remove a harmful pollutant and recover back some of the
metal extraction costs, good green economics?
like sulphur dioxide can be removed by bubbling through an
alkali solution such as calcium hydroxide solution
('limewater') where it is neutralised and oxidised to
harmless calcium sulphate. Cleaning a gas in this way is
called 'gas scrubbing'.
operations will disfigure the landscape BUT it can be re–claimed
and 'landscaped' in an attempt to restore the original flora and
fauna. However in the case of a limestone quarry, I'm afraid
there is no way round the fact that huge chunks of beautiful
hills get carted away if we want to use it as useful mineral.
Issues related to
The cost of
extracting and purifying metals is quite varied for several reasons.
If the ore
is plentiful it is cheaper e.g. iron ore, but silver ores and
gold are much rarer and on that basis alone they would be a more
ores using coke (e.g. iron), made from cheap coal, is cheaper
than the electricity bill for extracting aluminium from its
molten oxide by electrolysis, but different metals have
different properties best suited for particular and different
speaking, more reactive metals (like Al) are more costly to
extract than less reactive metals (like Fe) because of the
different energy demands and ease of extraction, which may
sometimes be due to more costly technology.
RECYCLING – a very
good idea because mineral resources are limited and manufacturing
costs of many metals from their naturally occurring ores involves
costly energy and environmental issues.
material to obtain metals from to recycle
Before any metals can be
recycled the scrap metal must be collected.
The main problem is
separating the useful metal from the rest of the rubbish.
e.g. in domestic
recycling plants iron and steel objects can be plucked out with a
magnet, since most other materials are not magnetic.
The recycling process
Why recycle metals?
Reasons to recycle metals
Saves valuable finite
natural mineral resources – mineral sources cannot last forever!
Saves energy, so less
fossil fuels burned,
Reduces a waste disposal
problem e.g. less piles of rusting cars and reduces environmental
problems in general.
Any reduction in
landfill waste sites is a blessing on the environment, so this is
now a real drive to recycle metals, plastics, glass and paper.
Landfill rubbish sites are source of environmental pollutions from
toxic materials leaching out and a health hazard from rotting
decomposing organic material.
Apart from reducing the
accumulation of waste, there are waste disposal management issues
e.g. how do store the waste? how dangerous is it? and environmental
scientists/technicians are needed to monitor possible pollution of
the surrounding air, water or land – more costs!
It is less expensive
than mining the original ore and extracting the metal, both these
processes are eliminated and far less energy is used overall, so on
several counts it will cost less money i.e. much more economic.
supply of copper–rich ores is limited so it is important to
recycle as much copper as possible especially as demand for
copper is growing as the economies of African countries, India,
China and Brazil etc. are rapidly developing and becoming
increasingly industrialised with the ensuing consumer demands for
all the eg electrical products that we in the West take for granted.
The future of metal
extraction from mineral ores?
There are still huge
deposits of mineral ores around the world which are and will be for
some time fully exploited by the industrialised nations – soon most
of the world?
ores are being depleted and because traditional mining and
extraction methods have major environmental impacts, there are
important issues involved and to be resolved in the future
exploitation of metal ore reserves.
Because of these issues,
new ways of extracting metals like copper from low–grade ores are
being researched hopefully to limit the environmental impact of
copper can be extracted by phytomining, or
The haze of pollution from Redcar Steelworks on the
North Sea coast of North East England. It is an important source of
employment and income into towns like Redcar. This steel works closed in 2010 and in an area already hard hit by the decline of
traditional heavy industry over the last fourty years but I'm glad to
say the steelworks reopened in 2012 providing much needed jobs for the
A mineral train of limestone
or lime filled wagons from Swinden Quarry in the Yorkshire Dales. The
local stone walls, barns and houses are also made of limestone – a
useful naturally occurring resource.
Issues related to limestone
WHERE NEXT? Other
associated KS4 Science GCSE/IGCSE chemistry web pages on this site
Notes information to help revise KS4 Science
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GCSE science–chemistry CCEA/CEA GCSE science–chemistry
(and courses equal to US grades 8, 9, 10) also useful revising and introduction to
metal extraction for A level AS/A2/IB chemistry students
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