Earth's resources Flashcards
define the term ‘gangue mineral’
gangue minerals are such that have no economical value, or the impurities in or around a mineral. Is usually the waste rock around the mineral of economic interest.
e.g. sand, quartz, dirt, etc.
define what a mineral deposit/ore body is.
A mineral deposit/ore body is defined as a volume of rock that contains one or more elements or minerals sufficiently above the average crustal abundance to be economically mined (a profit can be made if mined).
List 4 reasons why we cannot accurately estimate how many reserves we have.
- New discoveries
- Don’t know how much we will use (usage fluctuates)
- Unknown amount
- New technologies to extract new materials
Define what resources and reserves are.
Resources - What we currently know exists, but is not economical
Reserves - Materials that we can economically mine
What is a hypothetical resource?
We are certain that the minerals are there but we aren’t 100% certain.
How can we use more copper than we mine each year?
(Applies to more than copper)
Recycling the material.
What does economic and not economic mean?
Economic
Can make a profit by mining the reserve.
Not economic
Cannot make a profit/is too expensive to mine.
Can resources become reserves? How?
Yes they can. As other reserves are used up and the demand continues to grow, resources can become reserves.
Give 4 reasons as to why renewable sources of energy don’t contribute to the global demand.
- Low output of energy
- Not as profitable
- Still has environmental impact
- Have to convince people (noise pollution)
List 5 characteristics of a good placer deposit
- High density
- Insoluble
- Resistance to abrasion (deform not shatter)
- Little cleavage, minimal breakage or easy splitting
- Hard, hardness scale 1-10, diamonds are 10.
Name the four types of placer deposits and where they are found
- Eluvial (Next to vein on hill side)
- Colluvial (Down hill side, broken off of vein)
- Marine (Along coast, going with the current)
- Alluvial (River bed, inside of the bend or plunge pool)
Explain the process of a magmatic chamber cooling and the accumulation of minerals
As the magma body rises through the mantle it cools, and minerals crystallise, forming layers of different minerals.
Layers are dependent on melting point and density (highest melting point cools first and begins sinking first, however denser minerals may still make it to the bottom first)
Suggest a new use for an open cut mine
Fill in the open cut mine with the gangue minerals and waste materials, and use this open land (free of tall trees and buildings) as a solar plant. The existing power grid that once fed the mine could be converted to send the electricity the other way. Access roads around the mine can be used to maintain the solar plant.
Would save another (untouched) piece of land being disturbed.
List the 4 stages of coal
- Peat (Beginning of coal process, swamp vegetation compressed and buried by layers of sediment)
- Lignite (Low ranking coal)
- Bituminous (Medium ranking coal)
- Anthracite (High ranking coal, up to 90% carbon, most reactive)
What is meant by the ranking of coal?
The carbon percentage. If it has a high calorific value it gives off a lot of heat, therefore more valuable.
What are volatiles and what do they do?
Volatiles are nitrogen, hydrogen and oxygen and are a part of the coal.
They allow for minimal ignition energy making it easier for it to burn.
The more the better.
List 3 factors which affect the formation of coal
Pressure
Temperature
Time
Major part of coal question is what?
A graph.
Think carefully about it, take your time to figure it out before answering.
What does it mean to recontour an old mine?
To make it seem like the piece of land was never touched
What does reclamation mean?
To give an old mine a new beneficial use
What is the order of evaporites?
- Calcium carbonate (least soluble)
- Gypsum
- Halite
- Bittern salts (highest solubility)
Where do evaporites form?
Hot arid climates, near the coast in enclosed gulfs or lagoons.
How do evaporites form?
Abnormally high tides allow sea water to flood into the lagoon/gulf over the high embankments replenishing the water level VERY occasionally. The basin sinks, allows for more water, evaporates and that process repeats.
List the two kinds of oil traps
Anticline and fault trap
What is the order of the layers found in an oil trap?
Gas, oil, water - GOW
What is meant by a rock being porous or pervious?
Give examples
Porous
Water flows through pores which are gaps between the particles
Pervious
Have cracks or faults so water and oil can flow directly through the rock
Rocks can be one or the other or both
Examples of pervious and porous rocks are limestone and sandstone (these can be both)
Impermeable and Impervious rocks are mudstone and clay, but these are sometimes porous.
Describe an anticline trap
An arch in the rock layers which were originally laid down flat but the earth’s movement bent it into an arch. Oil and water moves its way through the permeable rock to the top where it is stopped by the cap rock.
Rock which holds the oil is known as the reservoir rock (mudstone and clay)
Describe a fault trap
Movement from the earth causes a break in the sediment layers. A fault line is created and the oil and water rises through the permeable rock, to then be stopped by the cap rock.
Rock which holds the oil is known as the reservoir rock (mudstone and clay)
