Lesson 5.2 Flashcards
are aggregates of minerals present in high concentration.
Regardless of whether it has high economic value or none, an accumulation of
minerals are still considered mineral deposits.
Mineral deposits
Mineral deposits are aggregates of minerals present in high concentration.
Regardless of whether it has high economic value or none, an accumulation of
minerals are still considered mineral deposits. However, when it is economically
valuable, it is called
ore deposit.
Four Groups of Mineral Deposits
energy resources
metal resources
industrial mineral resources
essential resources
can be further divided into fossil fuels and nuclear fuels. Fossil
fuels include natural gas, coal, oil shale, tar sand and oil while nuclear fuels include
thorium and uranium.
Energy Resources
include structural metals such as iron, copper, and aluminum as
well as economic metals such as gold and platinum. These resources also include
technological metals such as lithium and rare earth metals.
Metal Resources
include commodities such as salt, potash, and sand.
These minerals are widely used in the field of construction, chemical industries and
even agriculture.
Industrial Mineral Resources
are minerals that pertain to those needed by living organisms.
These minerals are found in soil and water. One good example of essential
resource mineral is zinc that is naturally present in water and soil.
Essential Resources
In the lithosphere, minerals are present everywhere but usually in minute amounts.
Therefore, high quality ore should be located in small area for mining to be
profitable. Searching for valuable ore is called
mineral exploration.
refers to the
concentration of the valuable minerals in an ore deposit.
Grade
minimum
concentration required to profitably extract the ore is called
cut-off grade
minerals that have no commercial value.
gangue minerals
The technology nowadays provides a means to search for high quality ore without
doing the actual mining. Various exploration techniques were used to assess ore
deposits prior to mining. These techniques include
remote sensong
geophysical methods
geochemical methods
This method uses devices such as sonar, radar, and satellite images to gather
image representation of the earth’s surface. These representations aid us in finding
for probable mining sites.
Remote Sensing
is a technique that uses the properties of minerals and geology to determine its location
An example is diamond extraction. Through volcanic pipes,
diamond bearing rocks known as kimberlites were carried from the mantle to the
surface. Geologists search for these ancient volcanic pipes when looking for
diamond deposits. The illustration below shows the first kimberlite pipe discovered.
It is located in South Africa. The big hole was created after the pipe was excavated.
Geophysical Methods
Merging the idea of the chemical properties of minerals and geology of a location,
compounds present in the ore and its abundance will be identified.
Geochemical Methods
Two Methods of Mining
surface
underground
extraction of valuable minerals from mineral deposits
Mining
is being used to extract ore minerals near the surface of Earth. This
type of mining is being performed to obtain sand, gravel, coal, phosphates, iron,
copper, and aluminum. It is usually preferred than underground mining since it is
less expensive, safer, and it involves less electricity and water. However, it poses
more environmental problems than underground mining. The soil and rocks that
cover the ores are being removed through blasting. Blasting is a controlled use of
explosives and gas exposure to break rocks.
Surface mining
five types of surface mining.
strip mining
open-pit mining
dredging
mountaintop removal mining
highwall mining
is usually used in extracting coal. This type of mining is ideal on
surfaces that are flat and horizontal. In this method, a thin strip of layer is removed
above the mineral deposit, and wastes are dumped just behind it. Once the mineral
deposit is exposed, another strip parallel to the first strip is made, and this time, the
wastes are dumped on top of the first strip. This is the cheapest type of mining, but
it produces the largest environmental footprint.
Strip mining
also known as open-cast mining, is considered as the most
common type of surface mining. It is usually used to extract near-surface deposits
like sand and gravel. This type of mining creates an open pit mine or a large-scale
hole in the ground that is continuously enlarged by blasting and drilling the rocks
apart. The mine becomes cone-shaped with benches or steps spiraling from top to
bottom when exposed in a cross-section. This orientation allows the trucks to go
down the mine from the sides while collecting the blasted debris.
Open pit mining,
is a type of mining that is used to collect unconsolidated materials from
bodies of water. Although this type of mining does not contribute to chemical
pollution, it still affects diversity of organisms in the water by dispersing fine
particles over a large area. In the long run, it could degrade marine habitats by
disrupting water currents and sediment placement.
Dredging
is a form of strip mining where the mountaintops
are removed to extract coal, and the wastes are dumped to nearby areas called
valley fills.
Mountaintop removal mining
is an open-cut mining which can be a combination of surface and
underground mining. This type of mining is usually used in coal extraction. Rocks
are drilled beneath the ground which can be very dangerous, especially when there
is undermining on the high wall causing the ground to become unstable.
Highwall mining
is used to extract the rocks, minerals, and other precious
stones that can be found deep beneath Earth’s surface. The underground mining
requires the creation of a tunnel so miners can reach the ore minerals. This kind of
mining is more expensive and dangerous as compared to surface mining because
miners need to use explosive devices to remove the minerals from the rocks
surrounding them.
Underground mining
types of underground mining
room-and-pillar mining
shrinkage stoping
vertical crater retreat (VCR).
a method used to extract mineral resources that are
deep and tabular. Pillars are left to support the hanging wall. Rooms and pillars are
arranged in regular patterns where pillars are designed with circular or square
cross sections separating the rooms.
Room-and-pillar mining
is a method where the ore deposits are excavated by slicing a
horizontal pattern, starting from the bottom of the deposit going upwards.
Shrinkage stoping
a method that uses crater blasting techniques
where powerful explosives are placed in big holes. This method is widely used by
miners worldwide.
Vertical crater retreat (VCR)
