Class 8 Social Science Mineral and Power Resource Exam Notes

Class 8 Social Science Mineral and Power Resource Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

Covers the following topics:

Minerals and power resources are the natural wealth that supports industries, transport and daily life. This Class 8 Social Science exam notes page on Mineral and Power Resources covers the characteristics and classification of minerals, methods of mineral extraction, the distribution of minerals in India and across the world, uses and conservation of minerals, and the conventional and non-conventional sources of power such as coal, petroleum, hydel power, solar, wind, nuclear and geothermal energy.

Topics Covered

1. Introduction to minerals
2. Characteristics of minerals
3. Classification of minerals
4. Extraction of minerals
5. Distribution of minerals
6. World distribution of minerals
7. Uses of minerals
8. Conservation of minerals
9. Introduction to power resources
10. The conventional sources of power
11. The non-conventional sources of power
12. Conservation of sources of energy

INTRODUCTION

A mineral is a naturally occurring substance with a definite chemical composition, having one or more elements. Minerals are found in the rocks. The uppermost layer of the earth is known as the crust, in which minerals are found buried abundantly.

CHARACTERISTICS OF MINERALS

Minerals provide raw materials to the industries. They are useful to man in various ways. Following are some of the characteristics of minerals.
(i) They are found everywhere in nature.
(ii) They are both organic and inorganic in nature. Coal, petroleum and natural gas are organic minerals, whereas iron, copper, manganese, etc. are inorganic minerals.
(iii) Metallic minerals are not readily usable. They are found in the form of ores. An ore is an aggregate of minerals usually found in the rocks. From these ores, metals are separated by heating or melting.
(iv) Minerals are very useful in our daily life. Their usage ranges from the utensils in which we eat food to the car we drive.
(v) They are also used in electrical appliances. For example, wires and cables.
(vi) Most minerals occur in the crust of the earth, but some are formed very deep in the earth, like petroleum and natural gas.

CLASSIFICATION OF MINERALS

Minerals differ in their structure, colour, hardness, solubility, etc. Hence they can be classified on the following bases.

Metallic Content

Metallic minerals: Minerals from which we get metals like iron, copper, gold, silver, lead, aluminium, tin, etc. are known as metallic minerals. These minerals have to be extracted from the ores in which they are present along with some other materials. Nowadays they are very precious and useful.
Non-metallic minerals: Minerals which do not contain metals are known as non-metallic minerals. Coal, petroleum, nitrate, potash, mica and gypsum are some of the non-metallic minerals. Although minerals are generally inorganic in nature, some are organic. Coal and petroleum are minerals that originated from plant and animal remains. These minerals produce heat and energy and hence are called fuels. They are also known as fuel minerals.

Iron Content

Metallic minerals are further classified on the basis of their iron (Fe) content.
Ferrous minerals: Minerals which have iron content are known as ferrous minerals. These are iron, cobalt, nickel, manganese, etc. They are basically used in the iron and steel industries. They are greyish in colour.
Non-ferrous minerals: Minerals which do not have iron content are referred to as non-ferrous minerals. For example, gold, copper, tin and aluminium. They are found in all types of rocks.

EXTRACTION OF MINERALS

The process of taking out minerals from rocks buried under the earth's surface is called mining. Minerals that lie at shallow depths are taken out by removing the surface layer. This is known as open-cast mining.

Deep bores, called shafts, have to be made to reach mineral deposits that lie at great depths. This is called shaft mining. Petroleum and natural gas occur far below the earth's surface. Deep wells are bored to take them out. This is called drilling. Minerals that lie near the surface are simply dug out by the process known as quarrying.

DISTRIBUTION OF MINERALS

(i) Minerals occur in different types of rocks.
(ii) Generally, metallic minerals are found in igneous and metamorphic rock formations that form large plateaus.
(iii) Iron ore in the North of Sweden, copper and nickel deposits in Ontario, Canada, and iron, nickel, chromites and platinum in South Africa are examples of minerals found in igneous and metamorphic rocks.
(iv) Sedimentary rock formations of plains and young fold mountains contain non-metallic minerals like limestone.
(v) Limestone deposits of the Caucasus region, manganese deposits of Georgia and Ukraine, and phosphate beds of Algeria are some examples.
(vi) Mineral fuels such as coal and petroleum are also found in sedimentary strata.

WORLD DISTRIBUTION OF MINERALS

Asia
China and India have large iron ore deposits. The continent produces more than half of the world's tin. China, Malaysia and Indonesia are among the world's leading ten producers. China also leads in the production of lead, antimony and tungsten. Asia also has deposits of manganese, bauxite, nickel, zinc and copper.

Europe
Europe is the leading producer of iron ore in the world. The countries with large deposits of iron ore are Russia, Ukraine, Sweden and France. Mineral deposits of copper, lead, zinc, manganese and nickel are found in eastern Europe and European Russia.

North America
Iron ore, nickel, gold, uranium and copper are mined in the Canadian Shield region, and coal in the Appalachians region. The Western Cordilleras have vast deposits of copper, lead, zinc, gold and silver.

South America
Brazil is the largest producer of high grade iron ore in the world. Chile and Peru are leading producers of copper. Brazil and Bolivia are among the world's largest producers of tin. South America also has large deposits of gold, silver, zinc, chromium, manganese, bauxite, mica, platinum, asbestos and diamond. Mineral oil is found in Venezuela, Argentina, Chile, Peru and Colombia.

Africa
Africa is the world's largest producer of diamonds, gold and platinum. South Africa, Zimbabwe and Zaire produce a large portion of the world's gold. Other minerals found in Africa are copper, iron ore, chromium, uranium, cobalt and bauxite. Oil is found in Nigeria, Libya and Angola.

Australia
Australia is the largest producer of bauxite in the world. It is a leading producer of gold, diamond, iron ore, tin and nickel. It is also rich in copper, lead, zinc and manganese. The Kalgoorlie and Coolgardie areas of Western Australia have the largest deposits of gold.

Antarctica
Significant deposits of coal are forecast in the Transantarctic Mountains, and iron near the Prince Charles Mountains of East Antarctica. Iron ore, gold, silver and oil are also present in commercial quantities.

Distribution in India

Iron: India has deposits of high grade iron ore. The mineral is found mainly in Jharkhand, Orissa, Chhattisgarh, Madhya Pradesh, Goa, Maharashtra and Karnataka.
Bauxite: Major bauxite producing areas are Jharkhand, Orissa, Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra and Tamil Nadu.
Mica: Mica deposits mainly occur in Jharkhand, Bihar, Andhra Pradesh and Rajasthan. India is the largest producer and exporter of mica in the world.
Copper: It is mainly produced in Rajasthan, Madhya Pradesh, Jharkhand, Karnataka and Andhra Pradesh.
Manganese: India's manganese deposits lie in Maharashtra, Madhya Pradesh, Chhattisgarh, Orissa, Karnataka and Andhra Pradesh.
Limestone: Major limestone producing states in India are Bihar, Jharkhand, Orissa, Chhattisgarh, Madhya Pradesh, Rajasthan, Gujarat and Tamil Nadu.
Gold: The gold mines of Kolar in Karnataka are among the deepest in the world, which makes mining of this ore a very expensive process.
Salt: It is obtained from seas, lakes and rocks. India is one of the world's leading producers and exporters of salt.

USES OF MINERALS

Minerals are used in many industries. Minerals which are used for gems are usually hard. These are then set in various styles for jewellery. Copper is used in everything from coins to pipes. Silicon, used in the computer industry, is obtained from quartz. Aluminium, obtained from its ore bauxite, is used in automobiles and airplanes, the bottling industry, buildings and even in kitchen cookware.

CONSERVATION OF MINERALS

Minerals are a non-renewable resource. The rate of their formation is much smaller than the rate at which humans consume them. It is necessary to reduce wastage in the process of mining. Recycling of metals is another way in which mineral resources can be conserved.
Ways to conserve minerals:
(i) Recycling: It means using discarded materials once again. Many metals like iron, gold, copper and aluminium become reusable through recycling.
(ii) Avoid wastage: Minerals can be conserved by using efficient methods of extraction and processing and by avoiding wastage. Saving can be done at the consumption level also.
(iii) Substitutes: In recent years, biodegradable plastics and other substitutes have been used to conserve mineral resources.

POWER RESOURCES

The sources of power which have been in common use for a long time are called the conventional sources of power. These include firewood, coal, petroleum, natural gas and electricity.

THE CONVENTIONAL SOURCES OF POWER

Firewood
The most important single use of wood from the forest is as fuel. Most people living in underdeveloped countries use wood for domestic cooking and heating. In India, most tribals and people living in villages use firewood as the main source of fuel. Most tropical countries have a high consumption of firewood.

Fossil Fuels
Millions of years ago, the remains of plants and animals were buried under the earth by the forces of nature. The large amount of heat and pressure inside the earth converted these remains into fossil fuels, such as coal, petroleum and natural gas. These are the main sources of conventional energy. The reserves of fossil fuels are finite and limited. Their consumption is rapidly increasing in the modern world faster than their rate of formation. Thus, one day or the other, fossil fuels are likely to be exhausted. They cannot be replenished like commodities derived from the plant and animal kingdoms. Thus, we must develop alternative sources of power.

Coal
Coal was used for centuries to provide heat for domestic uses. In the 18th century, it was used to produce steam power and thus became the basis of the Industrial Revolution. Coal remained the most efficient fuel for running factories and railway locomotives. It is also used to generate electricity, which is called thermal electricity.
The coal we mine and use today was formed millions of years ago under the surface of the earth, where vegetal material grew luxuriantly in bogs and swampy areas. It was embedded between layers of sand, silt and clay. Coal is categorised into four varieties: peat, lignite, bituminous and anthracite. These are classified on the basis of their carbon content and the amount of impurities present in them.
The coal mining methods are influenced by (i) the nature of coal occurrence, (ii) the thickness of the coal seams, (iii) the type of coal, and (iv) the mode of operation. Basically, coal is mined either on the surface or underground, with minor variations according to locality.
The main coal producing countries in the world are China, USA, Russia, Germany, Poland, UK, South Africa and India. Jharkhand is the important producer of coal in India. The main coal centres in India are Raniganj, Jharia, Dhanbad and Bokaro.

Petroleum
Petroleum, or mineral oil, was in use from ancient times in Iraq and Egypt. The modern petroleum industry came into being only after 1859 AD, when the first oil well was drilled in Pennsylvania (USA). Mineral oil is found in sedimentary rocks. Crude oil is taken out by drilling wells in the oilfields. On refining, crude oil gives a large variety of products, such as petrol, diesel, kerosene, wax, plastic and lubricants. Because of its value in our daily life, crude petroleum is known as Black Gold.
More than half of the total reserves of petroleum are located in the Middle East countries of Asia. Saudi Arabia has the largest reserves of oil. The main petroleum producing countries are Saudi Arabia, Iran, Iraq, Qatar, UAE, USA, Mexico, China, Venezuela, UK, Nigeria, Kuwait, Libya, Russia, Indonesia and India.
In India, the main oil-producing regions are Digboi in Assam, Mumbai High off the coast of Mumbai, Gujarat, and the deltas of the Krishna and Godavari rivers.

Natural Gas
Natural gas is found associated with mineral oil in most oilfields. It gets released when crude petroleum is drilled and taken out from the oilfields. Previously, this gas was allowed to go to waste. Now, it is used as a domestic and industrial fuel. The main producers of natural gas are Russia, USA, Netherlands, China, Iran, UK and India. Today, the USA is not only the largest producer but also the largest consumer of natural gas. In India, efforts are being made to discover new reserves of natural gas. The important natural gas producing regions in India are Gujarat, Tamil Nadu and the Krishna-Godavari region.

Hydel Power
The force of running water has been used for a long time to drive paddle wheels. The invention of the turbine and the dynamo made it possible to use hydropower to generate electricity. The source of hydropower is inexhaustible. The amount of energy in running water depends upon the volume of water and the velocity of the current. The water discharged from the turbine after generating hydroelectricity is used for irrigating farmland. The leading producers of hydroelectricity in the world are USA, Canada, Russia, China, India, Sweden, UK, New Zealand, Australia and South Africa. In India, a large number of multipurpose projects have been developed across rivers, not only for generating hydroelectricity but also for the overall development of the river basin. Find out the names of such multipurpose projects.

THE NON-CONVENTIONAL SOURCES OF POWER

Less than 200 years ago, most people in the world used wood to cook food and heat homes. One way in which the world has changed in the last 200 years is the amount of energy it consumes. Almost all this energy comes from fossil fuels, which cannot be replaced. The world is already facing a shortage of fossil fuels. Thus, there is a need for increasing use of non-conventional sources of energy, such as solar energy, wind energy, nuclear energy, geothermal energy, tidal energy, biogas, etc.

Solar Energy
The sun radiates an enormous amount of energy. If a small portion of that energy could be captured and converted into electricity, all the earth's energy needs could be satisfied cheaply, easily and without any damage to the environment. Sunlight can be changed into electricity with the use of solar cells, which are made mostly of silicon. This can help tropical countries, where there is enough sunshine. But solar cells are very expensive.

Wind Energy
The power of the wind has been used for centuries to drive mills and pumps. Wind power can be used to move the blades of windmills. Some windmills run generators to produce electricity. Now, wind farms have been established in many parts of the world. They have a number of windmills in a small area. Windmills work best on tops of mountains, along sea coasts and in open plains, where strong and steady wind blows. The main countries which have developed the technology for producing energy on a large scale are Netherlands, Germany, Denmark, UK, USA, Spain, India, etc.

Nuclear Energy
Nuclear energy is produced when changes are made in the nucleus of the atom. Energy is produced when the nucleus splits into two or more smaller nuclei, a process called fission. The atoms used in the fission process come from uranium or thorium. Nuclear fission takes place in nuclear reactors. The waste produced by nuclear power plants is radioactive and dangerous. The first nuclear plant was set up in the UK in 1956. Nuclear energy is now widely produced in USA, UK, Russia, Japan, China, Germany, France, Canada, Australia, Sweden, India, etc.

Geothermal Energy
Geothermal energy is the energy that comes from heat produced within the interior of the earth. The heat may come from magma or molten rocks in the crust. This can heat groundwater to form hot springs or geysers. It can be used to heat houses. The steam can also be used to run generators. Geothermal energy is widely used in Iceland. The other main users are USA, New Zealand, Italy, Philippines and Central America.
This energy is freely available and causes little or no pollution when electricity is generated from it.

Tidal Energy
The energy produced by the rise and fall of water due to the tides is called tidal energy. A dam is used to trap water at high tide, and it is released at the time of low tide. The rising and falling water can run generators and produce electricity. A few countries, such as Russia, France, UK and India, have developed tidal mill farms.

Biogas
The gaseous fuel called biogas can be obtained from organic wastes, which include dead plants, animal dung and kitchen waste. Biogas is a mixture of methane and carbon dioxide gases. These gases are released due to the decomposition of organic wastes. Biogas also produces organic manure. It can be used for cooking, heating and lighting.

CONSERVATION OF SOURCES OF ENERGY

(i) Conservation is possible by making use of renewable sources of energy.
(ii) Use energy in a planned way.
(iii) Burn waste to generate power.
(iv) Increase the power efficiency of machinery and appliances in general.
(v) Increase the efficiency of power stations.

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