CBSE Class 10 Social Science Minerals and Energy Resources Notes Set 05

How minerals occur

Minerals are found in veins and lodes (cracks and joints in igneous and metamorphic rocks), in beds or layers of sedimentary rocks, as placer deposits (alluvial deposits in sands of valley floors and hill bases), in ocean waters, and as residual mass of weathered material (for example bauxite).

Important minerals

1. Iron ore: the most abundant and basic industrial metal mineral. Magnetite is the finest ore with up to about 70 per cent iron and strong magnetic qualities; hematite has a slightly lower iron content (50-60 per cent) but is the most widely used. Main belts: Odisha-Jharkhand, Durg-Bastar-Chandrapur, Bellary-Chitradurga-Chikkamagaluru-Tumakuru in Karnataka, and Maharashtra-Goa.

2. Manganese: used in steel making, alloys, bleaching powder, paints and insecticides. Odisha is the leading producer.

3. Bauxite: the ore from which aluminium, a light metal with good conductivity, is extracted. Odisha is the largest producer.

4. Copper: malleable, ductile and a good conductor, so used in electrical cables and electronics. Main areas are Balaghat in Madhya Pradesh, Khetri in Rajasthan and Singhbhum in Jharkhand.

5. Mica: used in electrical and electronic industries because it is a good insulator. Found in Koderma-Gaya-Hazaribagh in Jharkhand and in Ajmer in Rajasthan.

6. Limestone: used in cement, and in the iron and steel industry.

Mining and conservation

Mining is often called a killer industry. Miners risk lung disease from dust and fumes, roof collapse and flooding, and fires in coal mines. Waste and slurry pollute water, land and air. Minerals are exhaustible and take millions of years to form, so they must be used carefully through recycling of metals, use of substitutes and less wasteful technology.

Conventional energy

1. Coal: found mainly in Gondwana deposits of Jharkhand, Odisha, Chhattisgarh and West Bengal. Lignite is a low grade brown coal with high moisture (Neyveli in Tamil Nadu); bituminous contains about 60-80 per cent carbon; anthracite is the best quality with over 80 per cent carbon.

2. Petroleum: major sources are Mumbai High, Gujarat and Assam (Digboi is the oldest field). It is the base of many industries.

3. Natural gas: a clean fuel; large reserves are in the Krishna-Godavari basin, and it is carried through pipelines.

4. Electricity: generated from hydro, thermal and nuclear sources. Uranium and thorium are the raw materials for atomic energy; thorium is found in the monazite sands of Kerala.

Non-conventional energy

Solar energy has great potential, especially in hot, dry regions with clear skies such as Rajasthan and Gujarat. Wind energy is strong in the Nagercoil-Madurai belt and in Andhra Pradesh, Karnataka, Maharashtra, Gujarat and Rajasthan. Biogas uses animal and farm waste. Tidal energy has potential in the Gulf of Khambhat, the Gulf of Kuchchh and the Sunderbans. Geothermal energy uses heat from the earth's interior; experimental projects are at Parvati Valley (Himachal Pradesh) and Puga Valley (Ladakh).

Key terms

1. Ore: a rock from which a metal can be extracted at a profit.

2. Placer deposits: minerals in alluvial sands of valley floors and hill bases, such as gold, silver, tin and platinum.

3. Rat-hole mining: illegal, narrow tunnel mining in the tribal areas of the North-East, done by individuals or communities and dangerous for workers.

4. Conventional sources: coal, petroleum, natural gas and electricity, which are mostly non-renewable except hydel power.

5. Non-renewable resources are exhaustible, so efficient use and research into new sources are needed.

Worked examples

Example 1. Why is solar energy promising in Rajasthan? The region is hot and dry with almost clear skies through the year, so sunshine is abundant. The source is renewable and pollution free.

Example 2. Give three reasons in favour of atomic energy. Coal and oil are exhaustible, India has deposits of uranium and thorium, and nuclear power is also useful in medicine and agriculture.

Example 3. Suggest ways to conserve energy. Use public transport, switch off unused appliances, use power-saving devices and adopt renewable sources.

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