OBOUR STEM SCHOOL
Geology lo 8,9,10
ACE team present
MIDTERM REVISION
WHAT ARE ORES?
• ORE IS A NATURAL ROCK OR SEDIMENT THAT
CONTAINS ONE OR MORE VALUABLE MINERALS THAT
CAN BE MINED AND SOLD AT A PROFIT.
• EXAMPLE: A ROCK THAT CONTAINS IRON
Properties of ores
• ORES ARE MADE OF DIFFERENT MINERALS
• ORES ARE METALS
• ORES ARE USUALLY FOUND IN IGNEOUS ROCKS
• ORES ARE NONRENEWABLE
• ORES ARE DENSER THAN COMMON ROCKS BECAUSE THEY
CONTAIN METALS WHICH MAKES THEM HEAVIER
• ORES DIFFER IN THEIR DISTRIBUTION AROUND THE WORLD
• ORES CAN BE FOUND IN BOTH THE ROCKS ON LAND AND SEAS
• ONLY A SMALL FRACTION OF ROCKS ARE CONSIDERED ORES
BECAUSE MOST OF THE ROCKS DON’T CONTAIN ECONOMICALLY
VALUABLE MINERALS FOR EXAMPLE A ROCK MAY CONTAIN A
LARGE AMOUNT OF CALCIUM BUT A SMALL AMOUNT OF
VALUABLE METALS LIKE IRON THESE ROCKS MAY BE SHALE OR
GRANITE ETC.
• THE TWO MOST USED METALS ARE IRON AND ALUMINUM
Where to find ores?
Orogenic belts: Areas where
Continent rocks: Mostly all mineral collisions have occurred between
resources are on the continents lithospheric plates creating an
especially older ones. uplift that contains a high
percentage of ores.
Hydrothermal activity: Any
Sea water: Low concentration, process associated with igneous
high amounts. activity involving the action of very
hot waters
Hydrothermal activity
Problems associated with mining
• Minerals may not be there as expected
• Minerals may not be concentrated
• Minerals may not profitable
• Drilling is very expensive
• Drilling is the sure way to confirm type & amount of minerals.
Mapping
• Mineral deposits are associated
with specific kinds of rocks.
Methods
Look for specific Look for folds, faults, Look for unusual colors
and rock formations that
Take rock
rocks and fractures in the
Earth’s layer aren’t consistent with samples to be
the environment.
analyzed
All of these are to make a
geological map
Geochemistry
• Study the chemistry of rocks and minerals by
samples taken up & analyzed.
• Analyse soil: surface & deep – plants for
absorption – groundwater – plant
life(vegetation) – water
• Study distributions & amounts of: (minerals –
rocks – ores - soils- water – atmosphere) and
their circulation in nature
Study the physical properties of
Earth and apply physical
measurements to geological
problems
Geophysics
Methods of geophysics
1- Seismic-wave reflection
• Use small explosions or steel plate
strikes.
• Record the time it takes to return and
the wave strength by geophones
• Measures depth and strength
Methods of geophysics
2- Earth’s gravitational field
• Measures acceleration due to gravity
by GRAVITIMETER (since large rocks
cause more gravitational force than
small ones).
• Most ores are denser than common
rocks
Methods of geophysics
3- Magnetometer
• Detect changes in Earth’s magnetic
fields
• Used for iron-bearing minerals
Gravity acceleration and magnetic field
Gravitational acceleration Magnetic field
• The force between 2 masses • The force between magnetic poles
• Depends on the movement of
electric charges
Methods of geophysics
3- Electric conductivity
If the rock conducts electricity, then
either
Rock contains a lot of water
Rock contains a lot of metallic
minerals
Mining
Surface mining Underground
mining
Surface mining
Types
Strip mining Open-pit mining
Stone quarries
Open-pit mining
Top
• Used when the ore is large and near soil(overburden)
the Earth’s surface
• Machines remove topsoil on the ore
and then return it back Spoil(gangue)
Ore
Open-pit
mining
When the deposit is in the form of
widespread thin sheet layers near the surface
Strip mining
Quarries
• Type of open-pit mining
• Used when the final product is
the large rock itself. The
product is not crushed
Underground mining
Used when the mineral resources lie deep in the Earth’s surface & when
an ore body is irregular
Achieved by shafts and tunnels
Shafts: vertical, sloped, or horizontal
Tunnels: more likely to being horizontal
Hazards of
underground
mining
• Cave-in: the collapse of the
roof or underlying structure
• Acid-mine drainage (AMD)
Solutions to underground mining
Pillars of ore and/or waste rock material are left to support the
mine roof.
Modern techniques include back-filling tunnels to recover ore
pillars
The grade of the ore and the strength of the overlying rock help
determine the size of the rooms and the support pillars.
Environmental concerns
-affect human health
-it causes soil erosion
-pollutes soil, water and air
-it is unsafe for humans and the environment
Cu and HG: their ores can easily be reduced by heating directly in air.
Some definitions
• Dredging: Removal of sediments &
debris from the bottom of lakes,
rivers, and harbors.
• Placers: A type of mineral deposit in
which grains of valuable minerals like
gold ore are mixed with sand deposits
by a river glacier.
• Placer mining: the mining of stream
bed deposits for minerals.
Veins
• Forms when very hot water
dissolves minerals from rock and
transports them into cracks where
the minerals precipitate out.
Subduction zone
• Earth's tectonic plates
dive back into the mantle
Taconic orogeny
• Mountain building period that ended 440
million years ago & affected most of
modern-day.
Mining
Depends on
•Location
•Size
•Depth
•quality
Questions
Minerals in placer deposited are:
A: open pits
B: by dredging (scooping out sediments)
C: on the deep ocean floor
D: deep underground
Questions
2-Mining nodules of minerals from the
ocean floor is currently cost-prohibited.
but could someday be economical.
feasible
A: subsurface mining
B: surface mining
C: placer mining
D: undersea mining
Questions
Which type of mining occurs when
gold is panned from a stream?
A: open pit
B: placer
C: strip
D: solution
Questions
- Dredging riverbeds may be an
effective technique for mining ....
A: silica
B: gold
C: coal
D: Sulphur
Questions
Which of the following is a source of
lead?
A: Bauxite
B: Hematite
C: Malachite
D: Galena
Questions
The oxide of ...... lightweight metal
form corundum, rubies, and sapphires
A: aluminum
B: copper
C: zinc
D: Lead
Questions
- Galena is the primary ore of which of
the following minerals?
A: Zinc
B: Tungsten
C: Lead
D: Silver
Questions
SphaleriteSphlerite is a primary ore of which
of the following mineral?
A: zinc
B: Tin
C: Copper
D: Iron
Questions
Hematite is a primary ore of which
of the following mineral?
A: Zinc
B: Tungsten
C: Iron
D: None of the above
Questions
Which of the following is a source of
copper?
A: bauxite
B: Hematite
C: Malachite
D: Galena
Questions
Steel makers add other elements to
iron to make
A: softer alloys
B: weaker alloys
C: alloys with special properties
D: More brittle alloys
Questions
An example of mineral made up of
pure element is
A: Coal
B: Copper
C: quartz
D: Glass
Questions
When steelmakers add chromium
and nickel to iron, the result is:
A: stronger steel
B: rust-resistant steel
C: Steel that melts easily
D: steel mixed with slag
Questions
In order to have mining, the area
must have
A: a much higher concentration of
minerals that are found elsewhere
B: large gold or silver deposits
C: Gemstones
D: Radioactivity
Questions
Which is not a major limitation in
predicting future mineral resources costs
and availability
A: Inability to predict new discoveries of
major mineral resources and reserves
B: Lack of basic knowledge of the types
of rocks and geologic environments that
mineral resources are found in
C: Inability to predict what technology
will be available in the future for
extracting minerals
D: Lack of understanding about the
environmental consequences of
extracting minerals
Questions
How are mineral reserves different
How are mineral reserves different from mineral resources?
from mineral resources? A: mineral reserves are more widespread
than mineral resources
B: mineral reserves contain lower
concentration of elements than mineral
resources
C: All mineral resources are mineral
reserves, while all mineral reserves are
not mineral resources
D: all mineral reserves are mineral
resources while all mineral resources are
not mineral reserves
Questions
The cost of creating a product from a
mineral deposit depends on:
A: The abundance of valuable mineral
from a deposit
B: Cost of extracting the mineral from
rock
C: Cost of refining the ore material
D: all of the above
Questions
Which term refers to anyone who
searches for ore deposits?
A: Geologist
B: Prospector
C: Miner
D: mineral specialist
Questions
Scientists who locate ore deposits
A: geologists
B: Environmental scientists
C: Soil scientist
D: Paleontologist
Questions
Scientists who locate ore deposits
A: geologists
B: Environmental scientists
C: Soil scientist
D: Paleontologist
Questions
Valuable mineral resources are:
A: evenly distributed around the planet
B: More highly concentrated in certain
locations by geologic processes
C: Collected by surface mining
techniques
D: Always profitable, or they wouldn’t
be called valuable
Questions
A mineral company is flying a plane
with a magnetometer over an area to
detect mineral deposits. Which element
is this method likely to detect?
A: Iron
B: Sulfur
C: Silicon
D: Carbon
