Chapter 5: Minerals and Energy Resources (Geography)

(b) bauxite

(b) mica

(a) sedimentary rocks

(c) thorium

See the two tables above.

Geologists define a mineral as a homogeneous, naturally occurring substance with a definable internal structure. Minerals are found in varied forms, from the hardest diamond to the softest talc, and each has particular physical and chemical properties based on its combination of elements.

A homogeneous, naturally occurring substance with a definable internal structure.

In igneous and metamorphic rocks, minerals may occur in the cracks, crevices, faults or joints. Molten or gaseous mineral matter is forced upward through these cracks, cools and solidifies as it rises towards the Earth's surface. The smaller occurrences are called veins and the larger are called lodes. Major metallic minerals such as tin, copper, zinc and lead are obtained from veins and lodes.

Molten or gaseous minerals are pushed up into cracks and joints of the rocks, where they cool and solidify as veins (small) and lodes (large).

• Minerals are finite and non-renewable: they take millions of years to form, much longer than the rate at which we use them.
• Only about one per cent of the Earth's crust consists of usable mineral deposits, and these are being consumed rapidly.
• Continued extraction means digging deeper, which raises costs and lowers the quality of the ore.
• Industry and agriculture depend heavily on minerals.

So we should use them in a planned and sustainable way, use recycled metals, scrap metals and substitutes, and improve technology to use low-grade ores profitably.

Because they are finite and non-renewable, take millions of years to form, are being used up fast, and become costlier as we dig deeper.

Coal in India occurs in rock series of two main geological ages:

• Gondwana coal (a little over 200 million years old): this is metallurgical coal. The major resources are in the Damodar valley (West Bengal–Jharkhand), where Jharia, Raniganj and Bokaro are important coalfields. The Godavari, Mahanadi, Son and Wardha valleys also contain coal deposits.
• Tertiary coal (about 55 million years old): it occurs in the north-eastern states of Meghalaya, Assam, Arunachal Pradesh and Nagaland.
• Lignite, a low-grade brown coal, is found at Neyveli in Tamil Nadu, where it is used to generate electricity.

Coal is a bulky material that loses weight on use (it is reduced to ash), so heavy industries and thermal power stations are located on or near the coalfields.

Gondwana coal is found mainly in the Damodar valley (Jharia, Raniganj, Bokaro) and the Godavari, Mahanadi, Son and Wardha valleys; tertiary coal in Meghalaya, Assam, Arunachal Pradesh and Nagaland; lignite at Neyveli in Tamil Nadu.

• India is a tropical country and receives abundant sunshine for most of the year, so it has enormous possibilities of tapping solar energy.
• Photovoltaic technology converts sunlight directly into electricity, and solar panels can be installed anywhere: on rooftops, in fields or in deserts such as Rajasthan and Gujarat.
• It is becoming popular in rural and remote areas, where the electricity grid does not reach easily.
• Big solar power plants are being set up in different parts of India. They will reduce the dependence of rural households on firewood and dung cakes, which will help conserve the environment and leave more dung for use as manure in agriculture.
• Solar energy is renewable, clean and pollution-free, and reduces our dependence on costly and limited fossil fuels.

Because India gets plenty of sunshine, solar technology works even in remote areas, and it is a clean, renewable source that reduces the use of firewood, dung cakes and fossil fuels.

Across: Manganese, Limestone, Magnetite, Anthracite, Bauxite, Copper, Gypsum. Down: Gold, Hematite, Mica, Tertiary, Tin.