Current Affairs 8th Class

Category : 8th Class

 

Mineral and Power Resources

 

 

To some extent our present civilisation has evolved by the use of minerals and energy resources. They provide the raw material to industries and energy to machinery; on which modern life depends. During the Stone Age, man used stones to make weapons. Then came the Bronze Age when man learnt the art of smelting ores. The Bronze Age was followed by the Iron Age. This period was characterised by a widespread use of iron. In this chapter we will learn about various mineral and power resources.

 

MINERAL RESOURCES

 

Our earth has some natural substances in rocks soil and sea beds. These natural substances found in nature, that have a definite chemical composition are called minerals. Minerals can be identified on the basis of their physical properties such as colour, lustre, density, hardness and chemical properties such as solubility.

 

TYPES OF MINERALS

 

There are over 3,000 different minerals found on earth. They are classified mainly as metallic and non-metallic minerals based on their composition. Minerals from which metals can be profitably extracted are called ores. Minerals that contain metal are called metallic minerals while rest of them are called as non-metallic minerals. Metallic minerals are also of two types,. Ferrous and Non Ferrous.

 

 

 

 

Extraction of minerals

The extraction of minerals from the earth is called mining. The method used for mining depends upon the depth at which the minerals are found. Minerals present near the earth's surface are simply dug out. It is called quarrying. Minerals which are present at shallow depth can be taken out by removing the surface layer. It is one of the easiest and cheapest methods of extracting minerals. This method is known as the open cast mining. To extract minerals which are present at great depths, a deep hole called shaft is dug. It is known as shaft mining. Deep wells are bored to obtain mineral oil like petroleum, and natural gas which occur far below the earth's surface by the process called drilling.

 

DISTRIBUTION AND UTILITY OF METALLIC AND NON-METALLIC MINERALS

Minerals are not evenly distributed over the earth. They are concentrated in particular areas, where rocks are formed. Some are found in igneous rocks, some in metamorphic rocks while others are found in sedimentary rocks. Iron ore in north Sweden, copper and nickel deposits in Ontario (Canada) and iron, nickel, chromite and platinum in South Africa are some examples of minerals found in igneous and metamorphic rocks. Limestone deposits of the Caucasus region of France and manganese deposits of Georgia and Ukraine are some examples of minerals found in sedimentary rocks.

 

IRON

 

Iron is the most abundant and useful metal. It makes up five per cent of the earth's crust. It has hardness, strength and ductility. It is used for making steel. Steel is used for making engines, ships, tanks, etc. There are different varieties of iron ore depending upon the iron content in them. The main varieties of iron ore are discussed here. Haematite is the finest iron ore with a very high iron content, up to 70%. It is red in colour and often referred to as red ore. Magnetite is the most important industrial ore but has a slightly lower content of iron as compared to haematite. It is dark brown to blackish in colour and is often referred as black ore. Limonite is yellow ore found in thick beds in sedimentary rocks over large areas of the world. It has an iron content of less than 50%. Siderite is ash grey in colour. It is a carbonate of iron found in sedimentary rocks, mostly near coalfields. The iron content is 20-30%.

 

World distribution

Europe is the leading producer of iron ore in the world. China, Russia, India, Ukraine, Sweden, Azerbaijan, South-East Asia, USA, Brazil, France/ Australia, Japan, Europe and Sweden have rich deposits of iron. South Africa is also a major iron ore producers.

 

Distribution in India

In India, the iron ore deposits are found in Sundergarh, Mayurbhanj and Keonjhar (Odisha), Singhbhum (Jharkhand), Bellary and Chikmagalur (Karnataka), Goa, Chhattisgarh, Madhya Pradesh and Maharashtra.

 

 

COPPER

 

Copper is a soft brown metal found only in igneous and metamorphic rocks. It is mixed with tin to obtain bronze. Copper is a good conductor of electricity. It is mainly used in electrical machinery, automobile and steel industry. Due to its relative scarcity, it is an expensive metal thus, a cheaper alternative i.e., aluminium is used as its substitute.

 

World distribution

Copper is found in every continent and small quantities of it are produced by a large number of countries. Chile is the largest producer of copper in the world. The other producers are USA and Russia. Copper deposits are also found in Peru, Canada, Zambia, Zaire, Poland, South Africa, Japan, Australia, Philippines, China, Mexico and Eastern Europe.

 

Distribution in India

Copper deposits are found in Hazaribagh, Santhal Pargana (Jharkhand), Madhya Pradesh, Andhra Pradesh and some parts of Karnataka.

 

TIN

 

Tin attained its present importance since the tin cans were invented. Since tin is non-toxic and resistant to corrosion, it is used to preserve food. However, nowadays plastic containers are also being used. The metal is rolled into thin sheets to make tin foils used in making collapsible tubes for ointments, tooth paste, etc. Tin is mixed with copper to make bronze, an alloy. Tin is alloyed with lead to make terne which is used to cover steel sheets (terne plates). Pewter is an alloy of tin mixed with the copper, antimony, bismuth and lead. Pewter is used for making ornaments and decorative objects.

 

 

Geography Reveals

Peter Durand, a British merchant, invented canning by keeping food in steel containers coated with a thin layer of tin and this revolutionised our eating habits!

 

 

Distribution in India

In India, Bihar, Jharkhand and Rajasthan are the main producing states of tin.

 

World distribution

Asia produces more than half of the world's tin. Malaysia is the world's leading producer and exporter of tin. Other producers are Brazil, Bolivia, Thailand, Nigeria, China and Indonesia. Although on a smaller scale, there are tin deposits in Australia, England, Burma, Japan, Canada and Spain.

 

ALUMINIUM

 

Bauxite is an aluminium ore and the main source of aluminium. It is used in making soda cans, dishwashers, siding for houses and other aluminium products.

 

World distribution

Australia is one of the top producers of bauxite followed by China, Brazil, Guinea and India.

 

Distribution in India

It is found in Jharkhand, Karnataka, Madhya Pradesh, Chhattisgarh, Tamil Nadu, Odisha and Maharashtra.

 

GOLD

 

 

Gold has a widespread distribution but it occurs in small quantities. It is used for making jewellery and other luxury items. It is alloyed with other metals like copper, zinc and silver.

 

World distribution

It is found in Canada, Japan, USA, South Africa, Zaire, Mexico and Zimbabwe. Kalgoorlie and Coolgardie areas of Western Australia have the largest deposits of gold.

 

Distribution in India

Gold is found in Kolar (Karnataka), Andhra Pradesh and Tamil Nadu.

 

DIAMONDS

 

The most valuable diamond gems are colourless or pale blue. They can be pink, green, lemon or black in colour too. Diamond is cut in a variety of shapes to give a maximum of facets (as many as 58) to reflect light to give the greatest brilliance. They are used for making jewellery. Inferior quality diamonds are used for industrial uses-for cutting glass and drilling into layers of the hard rocks. Diamond dust is used for polishing.

 

World distribution South Africa, Australia, South America, Ghana, Tanzania and Angola are the major producers.

 

Distribution in India Diamonds are found in Panna mines (Madhya Pradesh) and Golconda mines (Andhra Pradesh).

 

MANGANESE

 

It is used for making low cost stainless steel and alloys. It is also used in the textile industry and disposable batteries. Glass and ceramics can be coloured by using various compounds of manganese.

 

World distribution

Australia, Russia, South Africa, Brazil, China, Ghana and Morocco are the major producers of manganese.

 

Distribution in India

 

 

Manganese deposits occur in Maharashtra, Madhya Pradesh, Odisha, Karnataka, Andhra Pradesh and II Chhattisgarh.

 

MICA

 

Mica is used in a number of electrical appliances. Nowadays, its use is increasing in equipment that encounter very high temperatures like rockets and missiles.

 

World distribution

Mica deposits are found in South America.

 

Distribution in India

India is the largest producer of mica in the world. Deposits of mica are found in Bihar, Jharkhand, Andhra Pradesh and Rajasthan.

 

LIMESTONE

 

It is used in making cement, mortar and glass. It is crushed for use as aggregate?the solid base for many roads. It is used in blast furnaces to extract iron from its ore.

 

 

World distribution

Limestone deposits occur in Caucasus region of France.

 

Distribution in India

Major limestone producing states in India are Bihar, Odisha, Madhya Pradesh, Chhattisgarh, Gujarat, Rajasthan, Tamil Nadu and Jharkhand.

 

SALT

 

Salt is obtained from lakes, rocks and seas. It is used in manufacturing of various products we see around us. For example, textiles, glass, rubber and leather.

 

 

World distribution

Salt deposites are found in China, U.S.A. Germany, Canada, Australia, Mexico and Chile. China produces more than 22 per cent of salt.

 

Distribution in India

India is one of the world's leading producers of salt second largest in the world. Salt deposits occur in coastal Gujarat, Tamil Nadu, Andhra Pradesh, Maharashtra and Rajasthan.

 

CONSERVATION OF MINERALS

 

Minerals are non-renewable resources. Their rate of formation is slow as compared to the rate at which they are being used. It is absolutely necessary to use these resources judiciously, with minimum wastage while mining. Recycling of metals is another way of conserving our mineral resources.

 

Geography Reveals

South Africa has maximum mineral deposits that can cost 2.5$ trillion. While Switzerland and Israel are lowest in the rank of mineral deposits.

 

POWER AND ENERGY RESOURCES

 

The development of a country depends upon the power resources that it possesses. The power resources are actually energy or fuels. Fuels are substances which on combustion produce usable energy in the form of heat and light. Power resources are required everywhere, in agriculture, industries, transport communication and in homes too.  These are of two types-conventional and non-conventional.

 

CONVENTIONAL SOURCES OF ENERGY

 

Conventional sources of energy are those which have been in common use for a long time. Firewood, coal, petroleum and natural gas are conventional sources of energy. These are exhaustible sources of energy. Exhaustible sources or non-renewable sources are the sources of energy which cannot be replenished in a short period of time. They take a long time, to form, so they should be used judiciously. For example hydel power is a conventional source of energy but it is in-exhaustible. Coal, petroleum and natural gas against them are also inexhaustible source of energy. They are formed from fossils and hence are called fossil fuels.

 

Firewood

You know that in earlier times, wood was used as a fuel. Even today wood is used as fuel in rural areas in developing countries-to cook their meals and light their homes. Wood is a non-renewable or exhaustible conventional source of energy. Hence, its use as fuel needs to be restricted.

 

Fossil Fuel 78.4%

Nuclear 2.6%

Renewable 19.0%

 

 

 

Geography Reveals

 

 

Fossils are dead remains of living organisms trapped between layers of rocks. They are formed by the slow decomposition of dead plants and animals which had got buried deep under the surface of earth or ocean beds millions of years ago.

 

Coal

Coal is a sedimentary rock. It is the most abundantly found fossil fuel. It was formed millions of years ago by the decomposition of decayed plants. It is combustible. It is mainly composed of carbon. It is used as a domestic fuel in iron and steel industry, steam engines and to generate electricity. Electricity generated by burning coal is called thermal energy. On the basis of amount of carbon content in it, coal can be classified into four main types. These are peat, lignite, bituminous and anthracite.

 

 

Peat is the first stage in the formation of coal. It is soft and easily compressed. It has the lowest carbon content (50-60%). It is considered an inferior type of coal. Lignite is also low in carbon content (60-70%) and hence produces less energy. It has a high moisture content. It is generally used at power plants to produce electricity. It is also called the brown coal. Bituminous coal, also called the domestic coal, is the most commonly used coal. It is an important fuel for steel and iron industries. It is soft and black. The amount of carbon content in it is 70-85°%. Anthracite, formed very deep inside the earth, is the best quality coal. The carbon content in it is the highest (85-95%) of all the varieties of coal.

 

World distribution:?China is the largest producer of coal in the world. Countries with large coal reserves are USA, Russia, India, Australia and South Africa. Other important producers include Germany and France.

 

Distribution in India:?In India, coal is mainly found in Raniganj (West Bengal), Jharia, Dhanbad and Bokaro (Jharkhand), Talcher (Odisha), Korba (Chhattisgarh), Singareni (Andhra Pradesh), Neyveli (Tamil Nadu), Bihar, Madhya Pradesh and Maharashtra.

 

Petroleum

Petroleum (in Latin Petra means rock and oleum means oil) is also known as rock oil or crude oil. It was formed millions of years ago by decomposition of tiny sea animals and plants. It is a naturally occurring, thick, black liquid found in rocks deep inside the earth's crust from where it is drilled. It is then sent to refineries where it is processed and refined into more useful products such as diesel, lubricants, petrol, jet fuel, LPG, solvents, plastics and bitumen. Petroleum is very valuable so it is called black gold.

 

 

World distribution:?about 70% of the world's petroleum reserves are in the Middle East-Saudi Arabia, Qatar, Kuwait, Iran and Iraq. Libya, Russia, China, Siberia, United Arab Emirates, Venezuela, United States, Mexico, Algeria, Canada, Norway and Brazil also have large oil reserves.

 

Distribution in India:?in India, oil is found in Digboi (Assam), Gujarat, off the coast of Mumbai and in the river basins of Godavari and Krishna.

 

Natural gas

It is found along with petroleum deposits and is released when crude oil is brought to the surface. It is easy to transport through the underground pipes. It is stored under high pressure as Compressed Natural Gas (CNG). It is used in heating, cooking, power generation, motor vehicles and to produce nitrogen for fertilisers, and carbon black for use in the tyre industry.

 

World distribution;?the major producers of natural gas are USA, Russia, China, UK, Iran, Norway and the Netherlands.

 

Distribution in India:?India has a vast reserves of natural gas. Tripura, Jaisalmer (Rajasthan), Maharashtra and Krishna-Godavari delta are rich in these reserves.

 

Hydel Power

 

 

Hydel power generates the highest proportion of renewable energy, though it is only 6.5% of the world's total commercial energy. Water stored in dams is made to fall from a height. The falling water enters the dam through pipes. It falls on the turbine blades present at the bottom of the dam. The moving blades turn the generator to produce electricity called hydroelectricity. 20% of the world's electricity comes from hydel power. The leading producers of hydel power in the world are USA, Russia, Sweden, Norway, Paraguay, Brazil and China. The major hydroelectric power plants in India are Bhakra Nangal, Nagarjunasagar, Hirakud, Kosi, Rihand and Chambal.

 

 

 

Q. Compare these diagrams and find which source of energy has reduced and which one has increased in consumption in last four decades?

 

Advantages and disadvantages of hydel power

 

Advantages	Disadvantages
It is a renewable source of energy	Dams are expensive to build.
Darns store water and lessen the risks of flooding.	Decaying vegetation in the lake releases methane I and carbon dioxide to the atmosphere, increasing greenhouse gases.
The lakes behind the   dam   are used as wildlife sanctuaries.	There is a possibility of the darn collapsing.
It generates relatively   cheap form of electricity	Electricity cannot be stored once it is produced.
It causes limited pollution,	Silt spread over farmland gets deposited in the lake

 

Activity

Make a list of various sources of energy you use in your daily life. Categorise them into conventional and non-conventional sources of energy.

 

NON-CONVENTIONAL SOURCES OF ENERGY

 

Conventional sources of energy are depleting at an alarming rate. To meet the increasing demand for energy, non-conventional sources of energy are gaining importance. Solar energy, wind energy, geothermal energy, tidal energy, biogas and nuclear power are some of the examples.

 

Solar energy

It is estimated that the annual amount of energy received from the Sun is 7000 times greater than the world's current demand for energy. Solar energy is non-polluting and an inexhaustible source of energy. To produce solar power, a panel containing highly sensitive cells is exposed to sunlight. The cells can be used for solar water heaters or to convert sunlight to electricity. Solar panels are most efficient when placed on the roof in sunny, cloudless days.

 

 

Wind energy

It is also an inexhaustible source of energy. The wind blows onto the wind turbines and rotates them. Wind turbines transform the wind energy into mechanical power which can be used directly for grinding, etc., or converted to electric power to generate electricity. Wind turbines can be most efficient in areas with high and regular wind speeds such as exposed coast or upland areas.

 

Advantages and disadvantages of using wind energy

 

Advantages	Disadvantages
It is non-polluting	Winds do not blow all the time and electricity generated cannot be stored.
Local ecosystems are affected to a minimal extent.	The tall turbines spoil scenic beauty and harmful to birds.
After   the   initial expense of setting a wind farm, production of    electricity    is relatively cheap	Wind farms are noisy and disturb TV and radio reception of the communities  living close by
Wind farms provide a source of income to farmers and allow industries to flourish in those areas,	It is an expensive form of energy and very large number of wind farms are needed to generate substantial amount of electricity.

 

Wind farms are found in China, Germany, Spain, Denmark, Netherlands, USA and UK. There is a growing number of wind energy installations in a number of states across India. Some of them are Tamil Nadu, Maharashtra, Gujarat, Karnataka and Rajasthan.

 

Geothermal energy

Geothermal means heat from the earth. Heat is generated and stored beneath the surface of the earth. This energy is derived from hot springs and hot aquifers.

 

Rainwater seeps underground through cracks and crevices where it comes in contact with the hot rocks. The heat causes water to warm up, rise to the surface and get ejected as geysers, hot springs or steam. Geothermal energy can be used to generate electricity. USA has the world's largest geothermal power plants. Geothermal energy has been tapped in New Zealand, Iceland, Central America and Japan. In India, the potential sites for generating geothermal energy are Puga Valley (Ladakh), Tatapani (Chhattisgarh), Tuwa (Gujarat) and Jalgaon, Unai (Maharashtra).The cost involved in producing geothermal energy is high and it is limited to volcanic prone areas only.

 

 

Tidal energy

The rise and fall of sea water in coastal areas are called tides. Tidal energy can be used to turn the turbines and generate electricity. Several rivers around the world have a large tidal range that could generate electricity. Example of this energy being used is the Ranee Tidal Barrage in France. Gulf of Kutch in India has huge tidal barrages.

 

Amazing Facts

 

?  One wind turbine can produce enough electricity to bring power to 300 homes.

?   Unlike fossil fuels, renewable sources of energy like hydro, wind and solar energy do not emit greenhouse gases. ?   Surveys show that the world's resource base for geothermal energy is larger than the combined resource base for coal, oil gas and uranium.

Sources'.www.justgreen.coni.hk

 

Biogas

Biogas is produced by the biological breakdown of biomass such as animal dung, kitchen waste, urban waste and decaying plant matter. It is a mixture of methane and carbon dioxide. It is an excellent fuel for cooking and lighting. Large amounts of organic manure is produced from biogas plants which can be used to increase productivity in agriculture.

 

Nuclear power

Nuclear power is obtained by the fission of the nuclei of atoms of naturally occurring radioactive elements like uranium and thorium. In India, Rajasthan and Jharkhand have large deposits of uranium. Thorium is found in Monozite sands of Kerala. Nuclear power can be used to generate electricity. The leading nuclear power producers are USA and Europe. In India, nuclear power stations are located in Kalpakkam (Tamil Nadu), Tarapur (Maharashtra), Kaiga (Kamataka), and Narora (Uttar Pradesh) and. Kukrapura (Gujarat).

 

 

Advantages and disadvantages of using nuclear energy

 

Advantages	Disadvantages
Contributes less to the greenhouse effect and acid rain than the conventional fuels.	There are potential health risks associated with proximity to nuclear stations.
The numerous safeguards make the risk of any accident minimal,	Nuclear waste can remain radioactive for many years. There are problems of storing nuclear waste.
Nuclear waste is limited and can be stored underground,	An accident can kill and ruin an area for hundreds of years. Like Chernobyl in Ukraine.
Limited raw material requirement e.g., 50 tonnes of uranium per year compared with550 tonnes of coal per hour needed for thermal stations.	Time needed for formalities, planning and building up of a nuclear power plant is quite long.