6. Environmental Impact and Economics of Metal Extraction mining mineral extraction economic sociological environmental issues recycling metals igcse O Level KS4 science chemistry revision notes revising

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 often results in lots of waste material that must be dealt with from an environment of view.
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.
Examples of 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.
- Valuable revenue if the mineral or its products are exported.
- Jobs for people, especially new sources of employment in poor countries or areas of high unemployment in developed countries.
- Wages earned go into the local/national economy leading to improvements in schools, health service and transport etc.
- See Issues related to limestone quarrying
- Increase in local facilities promoted e.g. transport systems, like roads, recreational and health social facilities.
Examples of disadvantages of exploitation of mineral resources and reduction of its social and environmental impact:
- Dust from 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.
- Noise from process operation or transport of raw materials and products (lorries/trucks/wagons).
  - Difficult to deal with, sound–proofing often not practical, but operations can be reduced for unsociable hours e.g. evening movement.
- Pollution can be reduced by cleaning the 'waste' or 'used' air, water and waste gases etc. of toxic or acidic materials e.g.
  - Toxic carbon 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.
  - Sulphur 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?
  - Acidic gases 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'.
- Mining 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.
- See Issues related to limestone quarrying
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 valuable commodity.
- Reduction of 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 uses.
- Generally 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.
- Collection of 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
  - e.g. scrap iron is added to newly extracted from a blast furnace being converted into steel.
- 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.
- Example: The 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?
- However metal–rich 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 traditional mining.
- For example, copper can be extracted by phytomining, or by bioleaching.

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 Teesside area.

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.

WHERE NEXT? Other associated KS4 Science GCSE/IGCSE chemistry web pages on this site

Metallic Bonding – structure and properties of metals

Extra Electrochemistry–electrolysis theory, experiment designs and links to all electrolysis sections

Notes information to help revise KS4 Science Additional Science Triple Award Separate Sciences GCSE/IGCSE/O level Chemistry Revision–Information Study Notes for revising for AQA GCSE Science, Edexcel GCSE Science Edexcel IGCSE Chemistry & OCR 21st Century Science, OCR Gateway Science WJEC/CBAC 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

Website content copyright © Dr W P Brown 2000–2012 All rights reserved on revision notes, puzzles, quizzes, worksheets, x–words etc. * Copying of website material is not permitted chemhelp@tiscali.co.uk

Alphabetical Index for Science Pages Content A B C D E F G H I J K L M N O P Q R S T U V W X Y Z







		Custom Search