Class VIII - Geography

Chapter 3 - Mineral and Power Resources

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  • Minerals are naturally occurring substances that have a definite chemical composition.
  • Minerals are formed in different types of geological environments, under varying conditions such as evaporation of water, extreme heat and pressure.
  • Minerals can be identified on the basis of their
    • physical properties such as colour, density, hardness
    • chemical property such as solubility
  • Tropical regions are very rich in mineral resources.
  • Minerals are also found in rocks and sea bed.


Types of Minerals

  1. On the basis of composition, minerals are classified into
    1. metallic minerals
      • contain metals in raw form
      • are of two types:
        • Ferrous
          • contain Iron
          • Most of the Iron and steel industries and heavy industries depends on this mineral
        • Non-ferrous
          • do not contain iron but may contain some other metals like gold, silver, copper or lead
      • Metals are hard substances that conduct heat and electricity and have lustre or shine. For example, iron ore and bauxite.
    2. non-metallic minerals
      • do not contain metals
      • Examples are limestone, mica, gypsum, coal and petroleum.
  2. Minerals are mostly found in the form of ores and need to be extracted and purified before being used.
  3. There are three methods to extract minerals.
    1. Mining
      • is the process of taking out minerals from rocks that are buried under the earth’s surface
      • includes two methods
        1. Open cast mining
          • minerals are taken out from the shallow depths by removing the surface layer
        2. Shaft mining
          • deep bores called shafts are made to reach the mineral deposits that are deep under the soil layer
        3. Drilling
          • is where deep wells are bored to take the minerals out
        4. Quarrying
          • is where minerals that lie near the surface are simply dug out
        5. Mineral based industries are the backbone of industrial development of a nation.
        6. Mining needs cheap labour and resources to extract it off.


Distribution of Minerals

  • Minerals are found in igneous, metamorphic and sedimentary rocks.
  • Rocks appear different in colour due to the minerals present in them.
  • Metallic minerals are mostly found in igneous and metamorphic rocks like copper, nickel, platinum, chromites and iron.
  • The Ayers Rock in Western Australia is known to change colour every day and in every season depending on the light falling on it..
  • In sedimentary rocks, non-metallic minerals like limestone and phosphate and metallic minerals like manganese can be found.
  • Coal and petroleum are also found in sedimentary rocks.
    1. Asia produces more than 50% of the world’s tin.
    2. Among the world’s leading producers of tin are China, Malaysia and Indonesia followed by Brazil and Bolivia which are the largest producers of tin.
    3. Large deposits of iron ore are also found in India and China.
    4. Brazil produces high grade iron ore and is its largest producer in the world.
    5. India is the leading producer of mica in the world. 
    6. India is also one of the leading producers and exporters of salt.
    7. Deccan and Chota Nagpur plateau in India provide a rich level of mineral distribution.
      1. Iron and Bauxite can be found in Jharkhand, Odisha and Chhattisgarh
      2. Jharkhand, Bihar, Andhra Pradesh are major mica producing states.
      3. Gold deposits can be found in Kolar mines in Karnataka which are one of the deepest mines in the world.
    8. Europe is the leading producer of iron ore in the world.
    9. Chile and Peru are the leading producers of copper. 
    10. In South America there are deposits of gold, silver, zinc, chromium, manganese, bauxite, mica, platinum, asbestos and diamond.
    11. World’s largest producer of diamonds, gold and platinum is Africa.
      1. South Africa, Zimbabwe and Zaire produce a major part of gold in the world.
      2. Australia is the leading producer of gold, diamond, iron ore, tin and nickel and is the largest producer of bauxite.
    12. Switzerland has no known mineral deposit in it.


Uses of Minerals

  • Silicon is obtained from quartz and is used in computer industry.
  • Aluminium is obtained from its ore bauxite and is used in manufacture of automobiles, bottling and canning industries and even in cookware and foils. Aluminium Oxide or Aluminium Hydroxide is used safely in cosmetics, medicines and medical devices.
  • Granite is one of the hardest rocks found in nature and is used as building stone. It is made up of three minerals - quartz, feldspar and mica.
  • Gypsum is used in making Plaster of Paris which is used as cast on broken arms or legs.
  • Graphite is used in making lead for pencil and talc is used to make crayons and paints.
  • Sulphur is used in making matches, explosives, sulphuric acid, fertilizers, chemicals and dyes.
  • Mica is used in electrical appliances and glass making industries.
  • Copper is obtained from metallic mineral called chalcopyrite or copper pyrite. It is a good conductor of heat and electricity and is also so flexible that it can be rolled into flat sheets, wires and other shapes. Therefore it is used to make electrical cables, wires and switches. Copper is also used in making coins, utensils and pipes.
  • Iron is obtained from iron ores such as limonite, hematite and magnetite. Iron is mainly used
    1. to manufacture steel
    2. in almost all industries for manufacturing ships, airplanes, cars, cycles, trucks and vans
    3. in the construction industry to make building support and structures
    4. in the manufacture of computers and office stationery like staples, nails and paper clips
    5. Manganese is a key component in the production of iron and steel.
  • Gold and Silver are
    1. rare metals
    2. used to make jewellery, medallions and coins
    3. also used in dentistry and medicine
  • Certain minerals are called gemstones and are
    1. hard and come in various colours
    2. used to make jewellery
    3. Some gemstones like diamonds, sapphires, emeralds and rubies are rare and very expensive and are known as precious stones.
    4. Some gemstones like turquoise, garnet, amethyst, aquamarine, topaz, moonstone, peridot and opal are not as rare and are known as semi-precious stones.
    5. Gemstones are cut and polished first and then set into precious metals like gold, silver and platinum to make artistic jewellery.
    6. Diamond is the hardest mineral found on the earth and is used for making cutting tools for cutting other gemstones.
  • Minerals are also essential for all living beings.
    1. Iron is present in every living cell and is essential for the production of haemoglobin, which is the primary component of red blood cells.
    2. Other minerals like zinc, manganese, copper and fluoride are also required in very small amounts in our diet.


Conservation of Minerals

  1. Minerals are non-renewable resources and therefore it is very important to control their use and conserve them.
  2. The ways of conserving minerals are
    1. reduce the amount of waste
    2. recycle and
    3. reuse the metals


Power Resources

  • Power resources are required for industrial and domestic use, agriculture, transport, communication and defence.
  • Power resources are of two types
    1. Conventional Sources
      • The energy resources which have been in common use for a long time are known as conventional sources.
      • Firewood and fossil fuels are two main conventional energy sources.
      • Fossil fuels comprises of
        1. Coal
          • also known as buried sunshine
          • The major coal producing countries in the world are China, the USA, Germany, Russia, South Africa, and France. In India, the major coal producing areas are Raniganj, Jharia, Dhanbad and Bokaro in Jharkhand.
          • About 80% of coal is mined from the Damodar Valley.
          • Disadvantages of using coal as fuel are that it
          • is bulky to transport
          • is a source of pollution


        2. Petroleum
          • also known as black gold
          • The word petroleum means rock oil and is found between layers of rocks in the form of a thick black liquid.
          • Petroleum in its raw form is called crude oil which is drilled from oil fields located in off-shore and coastal areas.
          • The major petroleum producing countries in the world are Iran, Iraq, Saudi Arabia and Qatar.
          • A major advantage of petroleum is that it can be easily transported in tankers.


        3. Natural Gas
          • is found with petroleum deposits
          • is released when the crude oil is brought to the surface


        4. Hydroelectricity
          • is also generated from the energy of flowing water. The energy derived from flowing water is called hydropower.
          • The electricity generated from hydropower is called hydroelectricity.
          • Norway was the first country in the world to develop hydroelectricity.
          • The leading producers of hydro power in the world are Paraguay, Norway, Brazil, and China.
      • The fossil fuels are limited in stock and hence non-renewable so are important to be conserved.


    2. Non-Conventional Sources
      • Non-conventional sources of energy are renewable and unlimited in nature but are more expensive since they need technological upgradation.
      • Energy from the sun, wind and tides, nuclear energy, energy from the earth and from decayed organic matter are called non-conventional sources of energy.
      1. Solar energy
        • is an inexhaustible and non-polluting form of energy
        • is the heat/light of Sun which is the primary source of all energy on the earth
        • Solar panel, made up of a number of solar cells that absorb solar energy and convert it into electricity, are used to convert solar energy into heat and electrical energy
        • can be effectively used in tropical countries that receive abundant sunlight


      2. Wind energy
        • is the energy generated from winds
        • is renewable, low-cost, safe and clean source of energy
        • Wind mills are used to produce electricity
        • Disadvantages of wind energy are
          • it contributes to noise pollution
          • can be harmful to birds


      3. Tidal energy
        • is the energy generated from tides which are caused by the gravitational pull of the moon and the sun and the rotation of the earth
        • is a non-polluting and inexhaustible source of energy

      5. Nuclear energy
        • is the energy stored in the nuclei of radioactive elements like uranium and thorium
        • is produced during nuclear fission when the nucleus is split
        • During nuclear fission huge amount of heat and light energy is released.

      7. Geothermal energy
        • Geo = earth and thermal = heat
        • is the heat energy stored inside the earth
        • is clean and eco-friendly
        • can be seen dissipated on the earth’s surface in the form of hot springs, natural geysers and volcanoes


      8. Biogas
        • is also a renewable source of energy which is produced from biomass that includes wood from trees, matter from dead plants and animals, waste from other plants, animal dung and kitchen waste
        • can be used to generate electricity, light, heat, motion and fuel
        • is a low-cost source of energy, easy to operate, and uses bio-waste
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