Mineral : A homogenous, naturally occurring substance with a definable internal structure.
- They are found in varied forms in nature.
- Rocks are combinations of minerals.
- A particular mineral that formed from a certain combination of elements depends upon the physical and chemical conditions under which the material forms
- Because of this different minerals have different colour, hardness, crystal forms, lustre and density
Importance of minerals
- They are indispensable part of our lives.
- Life processes can’t occur without minerals.
- The food we eat contains minerals.
- Cars, buses are manufactured from 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.
Mode of Occurrence of Minerals
- In igneous and metamorphic rocks : The smaller occurrences are called veins and the larger occurrences are called lodes. Examples: tin, copper, zinc, lead, etc.
- In sedimentary rocks: In these rocks, minerals occur in beds or layers. Coal, iron ore, gypsum, potash salt and sodium salt are the minerals found in sedimentary rocks.
- By decomposition of surface rocks: Decomposition of surface rocks and removal of soluble constituents leaves a residual mass of weathered material which contains ores. Bauxite is formed in this way.
- As alluvial deposits: These minerals are found in sands of valley floors and the base of hills. These deposits are called placer deposits. Examples; gold, silver, tin, platinum, etc.
- In ocean water: Most of the minerals in ocean water are too widely diffused to be of economic importance.
- But common salt, magnesium and bromine are mainly derived from ocean waters
(i)Iron ore –
– Backbone of industrial development.
– Magnetite is the finest ore & has 70% iron.
– Hematite ore has 50 -60 % iron content .
– Limonite ore has 40 -60 % iron content .
– Siderite ore has 40 -50 % iron content
Production of iron ore showing state wise share
(ii) Manganese –
– Used in manufacturing of steel & ferro
-manganese alloy , bleaching powder , insectides & paints .
– 10 kg manganese required to manufactured 1 tone of steel .
– Largest producer – Orissa .
Production of manganese showing state wise share
Non – ferrous minerals
(i) Copper –
– Production of cu is critically deficient in India .
– Cu is malleable , ductile & a good conductor .
– Used in electrical cables & chemical industries .
– Malghat mines in MP produce 52% of copper .
– Khetri mines in Rajasthan is also famous for cu production .
(ii) Bauxite –
– It is a clay like substance .
– Bauxite deposits formed by decomposition of rocks rich in aluminium silicates .
– Aluminium combines the strength of metals with extreme lightness & with good conductivity & malleability.
– Largest producer – Orissa (45%)
Production of copper & bauxite
– Made up of a series of plates or leaves.
-It can be clear, black ,green or brown.
– Mica deposits r found in the northern edge of Chota nagpur plateau.
-Koderma Gaya – Hazaribagh belt of Jharkhand is the leading producer
– Found in association with rocks composed of calcium carbonates or calcium & magnesium carbonates.
– Found in sedimentary rocks.
-Raw material for cement industry.
– Essential for smelting iron ore in the blast furnace.
Production of limestone
Conservation of minerals
- Minerals can be conserved in by the following measures:
- Use of improved technologies to allow use of low grade minerals at low costs
· Using substitutes
· Use of scrap metals
· Recycling of metals is good way in which the
mineral resources can be conserved.
-They can be used in a judicious manner
- Understanding energy resources involves considering all types of energy source from various scientific and technological standpoints, with a focus on the uses, limitations and consequences of using energy that is available to humanity.
Conventional sources of energy
(i) Coal –
- Used for power generation , to supply energy to industry as well as for domestic needs
- India is highly dependent on coal .
- Formed due the compression of plant material over million of years .
- Lignite is a low grade brown coal , which is soft with high moisture content .
- Coal that has been buried deep & subjected to increased temperatures is bituminous coal
- Anthracite is the highest quality hard coal
(ii) Petroleum –
- It is Major energy source in India after coal .
- Provides fuel for heat , lighting & manufacturing industries .
- Also found in fault traps between porous & nonporous rocks .
- 63% of India’s petroleum production is from Mumbai High .
- Assam is the oldest oil producing state .
(iii) Electricity –
- It is mainly generated by 2 ways-
- Hydro electricity is generated by fast flowing water .
- Thermal electricity is generated by using coal, petroleum & natural gas. There r 310 power plants in India.
Non – conventional sources of energy
(i) Nuclear & atomic energy
– Obtained by altering the structure of atoms.
– Uranium & thorium r used for generating atomic or nuclear energy .
(ii) Solar energy
-Solar Energy is the energy received from the sun that sustains life on earth
-For many decades solar energy has been considered as a huge source of energy and also an economical source of energy because it is freely available
(iii) Wind power
-Wind power is produced by using wind generators to harness the kinetic energy of wind.
– It is gaining worldwide popularity as a large scale energy source .
- It is a mixture of methane and carbon dioxide it is a renewable fuel produced from waste treatment
- Biogas is best used directly for cooking/heating,
- light or even absorption refrigeration rather than the complication and energy waste of trying to make electricity from biogas
- Floodgate dams are build across inlets to use ocean tides to generate electricity.
- A 900 mw tidal energy power plant is set up at Gulf of Kuchchh by the National Hydropower Corporation.
Geo Thermal Energy
- The heat and electricity produced by using the heat from the interior is called Geo Thermal Energy.
- The steam rising from earth’s surface due to the heating inside earth is used to generate electricity.
- One such project is located in the Parvati valley near Manikarn in Himachal Pradesh and the other is located in the Puga Valley, Ladakh