Lithosphere (types of rocks - mineral extraction)

Okay, so when doing all four spheres, for each of them we have to focus on these four things:

1) Resources - means how the natural system is working, basically natural resources.
2) Development - as in how us humans have used them, what productive activity is done etc.
3) Impact - how is that development affecting the environment?
4) Management - how to do sustainable development. Okay?

Now, our first sphere, is Lithosphere. Whats Lithosphere? Its the outermost layer of Earth, basically comprising of crust and upper most solid mantle of Earth. (the rocks, soil, minerals all fall in lithosphere, they will be the resources, the elements of soil that we will study in this sphere)

This is the simplest picture I could find, see where lithosphere stands. Upper mantle aur continental crust, dono hain isma.. Lithosphere has solid mantle. Neeche wala molten hota hai. Thats not part of lithosphere. Okay?
Acha, there are different types of rocks in the Earth's crust, but they can be divided into three main groups.
1) Igneous 

• formed by fire - associated with volcanic activity
•  magma rises from mantle to the surface, and when it cools, forms igneous rocks
• two main types - granite & basalt
• granite is formed during formation of fold mountains, when magma is forced into rocks
• basalt is formed when lava cools after pouring out of volcanoes

2) Sedimentary

• made of sediment
• small sediments from rocks outcrop Earth's surface
• reach sea bed, and start accumulating in layers
• weight of the layers above compress the below ones into rocks
• examples - sandstone, limestone, & clay
• sandstone - has grains of sand
• limestone - dead sea creatures accumulate on sea bed forming layers of limestone rock
• clay - compression of deposits of mud

3) Metamorphic

• those that have been changed by heat & pressure in the crust
• how through heat? rocks in contact with new magma
• how through pressure? rocks on plate boundaries, bear stress due to great earth movements
• examples - limestone changed to marble, and clay changed to slate

Note: Igneous rocks,when observed have vertical lines of weakness, however sedimentary rocks have horizontal lines of weakness.

 Whats a mineral reserve?Its a known source of mineral, yet to be mined.
Some minerals can last hundreds of years like iron ore, while some run out more quickly.

Whats 'life expectancy' of a mineral?Number of years the mineral reserves are expected to last, keeping in mind the current rates of use.
How to calculate it?Amount of reserves existing / amount used per year.

Methods of extraction/mining:
1) opencast mining

• when? when minerals outcrop on the surface
• how? vegetation is cleared and topsoil is removed
• explosives used to loosen the rocks
• diggers used to remove loose rocks
• mineral (resource) loaded into trucks.

2) deep mining

• when? when mineral is deep down, underground
• how? take a geological survey to exactly spot the reserve (depth and position)
• sink a vertical shaft to the layer containing minerals
• then a horizontal tunnel is dug to the mineral site
• minerals are extracted by digging by miners and machines
• loose rocks are piled as waste heaps on surface, and minerals are also brought to the surface
• later they are loaded in trucks to be transported