Mineral and Power Resources Class 8 Chapter Notes

Key points

• Minerals are naturally occurring substances found in rocks; they may be metallic, non-metallic or energy minerals.
• A mineral becomes an ore when it contains enough metal to be extracted profitably.
• Minerals are unevenly distributed because their formation depends on geological processes over millions of years.
• Mining, drilling and quarrying are the main methods used to extract minerals from the earth.
• India has large reserves of iron ore, manganese, bauxite and mica, but petroleum reserves are limited compared to demand.
• Coal, petroleum and natural gas are conventional fossil fuels; they are exhaustible and cause pollution when burnt.
• Solar, wind, tidal, geothermal and biogas energy are non-conventional sources; they are cleaner and often renewable.
• Conservation of minerals means careful use, recycling, reuse and finding substitutes because minerals take millions of years to form again.
• Hydel power uses flowing water to generate electricity and is renewable, but large dams may displace people and affect ecosystems.
• Exam answers should include examples: iron ore in Odisha/Jharkhand, mica in Jharkhand/Bihar, bauxite in Odisha, petroleum in Assam/Gujarat/Mumbai High.

Important definitions

Mineral

A naturally occurring substance found in the earth’s crust with a definite chemical composition.

Ore

A rock from which a mineral or metal can be extracted profitably.

Mining

The process of taking minerals out from rocks buried under the earth’s surface.

Quarrying

Extraction of minerals that lie near the surface by digging open pits.

Drilling

A method used to extract deep underground resources such as petroleum and natural gas.

Conventional power resources

Traditional energy sources used for a long time, such as coal, petroleum, natural gas and hydel power.

Non-conventional power resources

Newer and often renewable energy sources such as solar, wind, tidal, geothermal and biogas energy.

Fossil fuels

Fuels formed from the remains of plants and animals buried for millions of years, for example coal, petroleum and natural gas.

Conservation

Planned and careful use of resources so that they last longer and are available for future generations.

Minerals: meaning, occurrence and importance

Minerals are important because they are the raw materials for industry, transport, buildings, machines and energy production. They occur in different types of rocks and are not spread evenly across the world. For example, a region may be rich in iron ore but poor in petroleum because different minerals form under different geological conditions. Minerals are extracted only when the quantity and quality make extraction useful and affordable. This is why the term ore is important: all ores are minerals, but all minerals are not ores. For Class 8 exams, remember that minerals are valuable but non-living, unevenly distributed and mostly exhaustible. Their careless extraction can damage land, pollute water and destroy forests, so mining must be balanced with conservation.

Classification of minerals

How minerals are extracted

1. Prospecting and exploration —
2. Choosing the extraction method —
3. Extraction —
4. Processing —
5. Transport and use —

Mining, drilling and quarrying: quick comparison

Conventional vs non-conventional power resources

Distribution of important minerals

Mini examples for exam answers

• Example 1: Mineral vs ore Bauxite is a mineral and also an ore because aluminium can be extracted from it profitably. But a mineral deposit with very low metal content may not be called an ore.
• Example 2: Why coal is called a fossil fuel Coal was formed from dead plants buried under heat and pressure for millions of years. It is called fossil fuel because it comes from ancient organic remains.
• Example 3: Conservation answer frame To conserve minerals, write: use carefully, reduce wastage during mining, recycle metals, reuse products, improve technology and use substitutes wherever possible.

Power resources: why energy matters

Power resources are needed to run homes, farms, factories, transport and communication systems. Without energy, machines cannot operate and economic development slows down. Coal is used in thermal power plants and industries, but it creates smoke and carbon dioxide. Petroleum is useful for transport fuels and petrochemicals, but reserves are limited. Natural gas is cleaner than coal and petroleum, yet it is still a fossil fuel. To reduce pollution and save exhaustible resources, countries are increasing the use of solar energy, wind energy, hydel power, tidal energy, geothermal energy and biogas. In exam answers, link power resources with both development and environmental responsibility.

Must remember: energy sources

• Coal is used for thermal electricity, iron and steel, cement and domestic fuel in some areas.
• Petroleum is refined into petrol, diesel, kerosene, LPG, lubricants and raw materials for petrochemicals.
• Natural gas is used as CNG, PNG, industrial fuel and in fertiliser production.
• Hydel power is generated by the force of falling or flowing water turning turbines.
• Solar energy is abundant in tropical countries like India and can be used for heating, lighting and electricity generation.
• Wind farms work best in coastal areas, open plains and highland regions with steady winds.
• Biogas is produced from animal waste and plant waste; it is useful in villages as a clean cooking fuel.
• Geothermal energy comes from heat inside the earth and is available only in suitable volcanic or hot spring regions.

Exam tips and common traps

Do not mix up minerals and power resources: minerals are substances found in rocks, while power resources are sources of energy. In 2-mark answers, define the term and give one example. In 3-mark answers, use a point format: meaning + example + importance/problem. For differences, make a table if allowed. Do not write that all conventional sources are non-renewable because hydel power is conventional but renewable. For conservation questions, include recycling, reducing wastage, reuse, substitutes and efficient technology. Location-based answers should mention states correctly; Odisha is important for iron ore and bauxite, while Mumbai High is important for petroleum.

YoLearn revision prompts

Quick revision checks

• Q: What is an ore? A: An ore is a rock from which a mineral or metal can be extracted profitably.
• Q: Name two non-conventional sources of energy. A: Solar energy and wind energy.
• Q: Which method is used to extract petroleum? A: Drilling is used to extract petroleum and natural gas.
• Q: Why should minerals be conserved? A: Minerals are exhaustible, take millions of years to form and are unevenly distributed.

FAQs

• Q: Are minerals renewable resources? A: Most minerals are non-renewable because they take millions of years to form. Once used up quickly, they cannot be replaced within a human lifetime.
• Q: What is the easiest way to remember mineral types? A: Use the memory chain: metallic, non-metallic and energy minerals. Under metallic, remember ferrous means iron-containing and non-ferrous means no iron.
• Q: Is hydel power conventional or non-conventional? A: In this chapter, hydel power is usually classified as a conventional power resource because it has been used for a long time. However, it is renewable because it uses flowing water.
• Q: Why are non-conventional energy sources important? A: They reduce dependence on fossil fuels and create less pollution. They are important for sustainable development and future energy security.
• Q: What should I write in a short note on conservation of minerals? A: Mention careful use, recycling metals, reducing waste during mining, using substitutes and improving extraction technology. Add that conservation is needed because minerals are limited and unevenly distributed.

Frequently Asked Questions