Topic 1 Flashcards
Igneous Rock
Came from volcanic activity when liquid magma from mantle cools to form solid crystallized rocks
Quick cooling forms small crystals while slow cooling forms large crystals
Molten rocks below surface is called magma and i called lava when it reaches surface E.g. basalt granite
Sedimentary rocks
Formed by weathering of existing rocks at the earth surface where sediments are transported by wind and water and sink to the bottom and accumulate into layers in the bottom of the ocean and gets pressurized due to newer deposits
Sedimentary rocks contains rounded grain so they are porous rocks
Has dead organism buried under layer of sediments so contains fossils
Shale sandstone limestone
Metamorphic rock
Formed from existing rocks when heat and high pressure causes changes in the rock without melting it . These changes could be chemical or physical or both
E.g. slate marble
5 methods of searching for minerals
Prospecting: a process of searching for minerals by examining the surface of the rocks.
Remote sensing: process in which information is gathered about the Earth’s surface fro
above.
(Aerial photography maps a large area and can çover more
ground than a person on the surface.
Aerial photography reaches inaccessible areas.
It shows the type of vegetation.
It shows geological characteristics like colors of rock and soil,
so images are carefully analyzed for mineral presence.
Radiation detection:
Mineral deposits are weathered at the Earth’s surface, forming mineral oxides.
They can be detected by their unique radiation pattern.
Satellite signals:
Some satellites send signals to the Earth’s surface and collect the reflected signals
indicating the presence of minerals.
The system works in allWeather conditions)
Geophysics: method to identify mineral ores present in rocks using their physical properties
A series of vibrations (seismic waves) are sent through the Earth’s surface.
Several sensors are placed at different distances from the source of vibrations on the surface.
The vibrations create shock waves that travel down into the rock layers.
They are reflected back to the sensors on the surface.
The shock waves record different patterns depending on
the mineral present in the rock layers.
Factors affecting decisions of extraction
o Exploration and cost of extraction:
Cost of extraction and machines is an important factor.
Low value ore or small size of deposit.
Open-pit mining is cheaper than shaft mining so only deposits of higher value can be mined this way.
Geology:
Rocks might not be profitable to extract if buried deep.
Concentration of desired mineral should be high enough to be extracted.
Stability of surrounding rock should be considered to avoid any accidents and ensure the safety the
of the workers.
○ Accessibility:
The mining company must be given a license before extracting a deposit.
Transporting the ore from the mine to processing plants can be difficult and expensive.
Carrying out processing at the mine reduces transport costs & increase value of the ore.
A long-term agreement between the government and mining company must be reached to avoid rapid rises in the tax, which makes the mining unprofitable.
Environmental impact assessment:
For a license application to be approved, the company must have a plan to keep the loss of habitat & damage to the environment minimal, followed by the restoration of land after
the completion of mining to encourage the company to dispose the wastes safely.
The assessment should include:
o Local people’s views
o Named pollution and how it will be controlled.
o How the land will be restored
o How the waste will be dealt with
o Risk to health
impact on environment
o Surveying the wildlife and ensuring there are no endangered species.
Supply and demand:
The relation between how much of a commodity is available and how much is needed or wanted by the consumers.
Increase in world demand for any mineral ore will elevate the prices. Decrease in world demand will reduce the prices.
If the demand is too high, mines that were not profitable before becoming worth mining. .If the demand falls, working mines may get into loss due to the extraction expenses.
danger of working in mine
Environmental impact if extraction
Loss of habitat: loss of Biodiversity disruption of food chains
High Risk of extinction of Some Species, Migration
Loss of habitat as the vegetation is cleared, so the animals depending on them for food and shelter are affected which causes loss of biodiversity.
After mining has been working for several years; more habitats will be destroyed due to the increased overburden above ground.
o Pollution AND its types:
Noise pollution: machinery and explosives disturb the behavior of animal species and causes hearing problems for people.
Water pollution: water supplies may be polluted due to leaching of heavy metals which
causes:
o Making it unsafe for people to drink.
O
The water may become acidic and dissolve toxic metal ions
O
This combination kills many aquatic organisms.
o This reduces crop growth.
Bioaccumulation: organisms ingest the toxin, the concentration of the toxin increases in the
body. The pollutant excretion rate is less than the ingestion rate.
Biomagnification: the concentration increases higher up the food chain and cause death of
top consumers.
Land pollution: toxic nature of the waste doesn’t allow plant growth even years after the mining has stopped.
Air pollution: dust particles settle on the vegetation, not allowing sunlight to reach the leaves and thus, reducing the rate of photosynthesis,
Breathing in dust that remains in the lungs can cause serious lung diseases.
Visual pollution: landscape is damaged.
Management of waste: a lot of mining waste is produced that have to be managed or else
it will cause pollution.
Economic impactor
Subsurface mining
2-Sub-surface mining: (deep mining / Shaft mining
A vertical shaft is sunk down to the rock layer containing minerals.
A horizontal tunnel is made, following the mineral layer.
The minerals are extracted by digging (by machines and miners).
The loose rock is brought from the mine and piled up on waste heaps on the surface.
The minerals are brought to the surface and transported in trucks or trains.
Strategies for sustainable use of rocks and minerals
Increasing the efficiency of the extraction of rocks and minerals:
Processing mine waste for the second time to allow the valuable minerals to be recovered
and reduce the risk of pollution due to mine waste.
Chemical treatment of the waste to extract much of the valuable mineral within it. Improvements in the performance of the machines used in mining and processing. Greater use of data analysis by computers (to predict geological conditions).
2- Increasing the efficiency of the use of rocks and minerals:
Engineering solutions e.g., design steel beams with same strength but using less steel.
3- The need to recycle rocks and minerals:
Introduce fines to ensure the manufacturers are responsible for recycling.
Provide easier collection using separate waste bins.
Increase the number of bins and the frequency of collection.
Encouraging the use of recyclable packaging.
> Recycling uses less energy than processing ores.
Recycling also produces less waste so reduces the risk of pollution.
4- Legislation:
The governments pass laws that require manufacturers to become responsible for recycling and reuse.
Surface mining
Surface mining: includes open-cast (open-pit, open cut) and strip mining.
A. Open pit mining: is used when a valuable deposit is located near the surface.
The vegetation is cleared, and topsoil removed.
The rocks are broken up and loosened using explosives.
Mining down as series of levels or layers.
The loose rock is removed using diggers.
The rock or mineral is tipped into trucks or railway
wagons to be transported away.
An open hole or pit from which stone is obtained by digging, cutting, or blasting is called Quarry
B. Strip mining: is used to mine a seam of mineral.
The overburden (overlying rock and soil) is removed as thin strip. It is mainly used to mine coal.
Managing impact of rock extraction
A-Safe disposal of mining waste:
Making waste piles safe from collapse.
Site of the mine must prevent the chances of water pollution.
BLand restoration:
Soil improvement
After sanitary landfilling, mine waste can be covered by a layer of soil that can be enriched With fertilizers
Bioremediation:
A process of removing pollutants from waste using living organisms.
In situ treatment: treatment of contaminated waste where it is left.
Ex situ treatment: removal of contaminated waste from a site to a treatment plant. Often happens slowly (can be sped up by providing oxygen and nitrogen). Microorganisms, like bacteria, can absorb pollutants and metabolize them into less harmful substances.
Some plants can bioaccumulate toxic metals.
。 Tree planting:
After improving the soil fertility
plants and trees can be grown in that
area, helping an ecosystem to be reborn
C-Making lakes and natural reserves:
o Natural Reserves:
Several tree and herb species are introduced.
As their populations grow, they create habitats for many species.
These natural reserves become valuable green spaces for human recreation and help in maintaining biodiversity
If the rock lining the hole (created by the extraction) is non-toxic and impervious to water,
it can be filled with water to form a reservoir or lake.
It is used for irrigating farmland or processed to provide clean, safe drinking water for
humans.
D- Using as landfill sites:
Landfilling: the waste is filled into a hole. From time to
time, it is levelled off and compacted.
O Sanitary landfilling: as in landfilling, the waste is used to fill the hole, but alternating layers of waste and sand are used
Advantages of surface mining
- Easier to discover and access.
- Cheaper to extract.
- Less risk of injury due to less risk of collapse, suffocation, and explosion.
- Quicker.
Economical impact of mining
More employment opportunities in
1- mining and extraction of minerals and rocks
2- transportation for extracted minerals
3.refining minerals to make products
Improvement in local and national economy
Where more payment balance so
More income
Increase wealth
Increasing standard of living
More taxes to government
Reliable source of raw material which is used in industry
Improvement in infrastructure anf facilities
To roads and transport
To services such as health cares and education
