Rocks and minerals their explotation

Rocks and minerals their explotation

Earth:

[pic 1][pic 2][pic 3][pic 4][pic 5][pic 6][pic 7][pic 8][pic 9]

Importance of crust for people

The different kinds of rocks provide useful products for humans such as building materials, minerals, metals, etc.

• Coverage of rocks and soil (differentiate from earth or floor)

[pic 10]

Weathering

(meteorización)[pic 11][pic 12][pic 13][pic 14][pic 15][pic 16][pic 17][pic 18][pic 19]

Weathering

1. Physical weathering

Can be caused by changes in temperature, frosting and defrosting, and changes in humidity

1. Chemical weathering

In this process, the content of minerales of the parental rock changes and forms new minerals.

The main chemical agent is water.

1. Biological weathering

The main agents are scavenger animals that decompose the rock, but also roots of plants and decomposers. The processes involve mechanical and chemical activity.

Weathering → DEPENDS on temperature and precipitations

Rocks and minerals

¿Which are the differences between rocks and minerals?

• Rocks

Inorganic and solid.[pic 20]

Formed by 2 or more minerals.[pic 21][pic 22]

[pic 23]

• Minerals

Inorganic substance, with 2 characteristics:

Has a defined chemical composition.

The atoms of the elements that composes the minerals are arranged in a certain order.

The most common elements are:

 O > Si > Al > Fe > C > Ca > K > Na > Mg > Ti

The rock cycle

[pic 24]

Types of rocks

Many types of rocks make up the Earth’s crust. These can be divided into 3 different groups based on how they form.

1. Igneous rocks:

Rocks formed by fire

Associated with the volcanic activity: Magma from the mantle reaches the surface during a volcanic eruption. Then, the lava, cools and hardens forming igneous rocks.

Eg: granite and basalt

1. Sedimentary rocks:

Formed by sediments that settles and compact.

Sediments are small parts of broken rocks which outcrop on the Earth’s surface by weathering and erosion.

When the particle reaches the sea bed, they settle and accumulate in layers.

Over time, the weight of new sediment compresses the layers below into sedimentary rocks.

Eg: sandstone, claystone , shale.

1. Metamorphic rocks:

Formed by heat and pressure

The change of heat on the crust is caused by new magma flow.

The change by pressure is caused when the plaques moves[pic 25]

Eg: limeston[pic 26]

Claystone[pic 27][pic 28]

ROCKS AND MINERALS

Rocks and minerals are cheap and easy to extract when they outcrop on or near the Earth’s surface.

Clear the vegetation and soil from the surface - start digging

The useful rock or mineral resource can then be extractead by:

Quarrying: extracting rock and stone from the surface

Opencast mining: extracting minerals from the surface

They both leave a large hole (open pit) in the ground. Other names for surface mining are open-cut and strip mining.

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