Chapter 16: Mining and Mineral
Resources
16.1 Minerals and Mineral Resource
A. What is a Mineral?
• Mineral is a naturally occurring, inorganic solid
that has a characteristic chemical composition
and physical properties.
• The atoms of minerals are arranged in regular
repeating geometric patterns.
• Native elements are minerals made of only
elements (gold, silver and copper)
• Most minerals are compounds
B. Ore Minerals
• Ore minerals are minerals that are valuable and
economical to extract.
• Gangue minerals are minerals that have no commercial
value
• 1. Metallic Minerals
• Metals conduct electricity, have shiny services and are
opaque
• Valuable metallic minerals are native elements such as
gold, silver and copper.
• 2. Nonmetallic Minerals
• Nonmetals tend to be good insulators, have shiny or dull
surfaces and may allow light to pass through them.
• Nonmetallic minerals can be native elements or
compounds.
B. Ore Minerals
C. How do Ore Minerals Form?
The types of minerals that form depend on the environment
in which they form
1. Hydrothermal Solutions
• Hydrothermal solutions are hot subsurface waters that
contain dissolved minerals.
• As they flow through cracks in rocks they dissolve minerals
• New minerals crystallized out of the solutions then fill
fractures to form ore deposits called veins
2. Evaporites
• Water in the seas or lakes evaporates deposits of salts are
left behind
• Evaporates form in arid regions where rates of evaporation
are high
• Include rock salt and gypsum.
D. Mineral Resources and their Uses
• Some metals can be pounded or pressed into
various shapes or stretched very thinly
• Some are good conductors of heat and electricity
• Alloys are formed when two or more metals are
combined
• Nonmetals are most widely used minerals in the
world
• Gemstones are nonmetallic minerals prized
purely for their beauty, rarity, or durability.
Stop here and complete 16.1 active
reading worksheet
19.2 Mineral exploration and Mining
A. Mineral Exploration
• 1st step in finding an ore deposit is exploring rock
for mineralization.
• Planes carry instruments that identify patterns in
the land
• 2nd step rock samples are taken from the areas
and analyzed to determine ore grade
B. Subsurface Mining
• Subsurface mining is how ore deposits beneath
Earth’s surface.
• Room-and-pillar mining is a common method
used to extract coal and salt.
• Networks of entries (rooms) are cut into a
horizontal layer of coal.
• Between each room is a pillar of coal left to
support t the roof.
• When mining is complete the pillars of coal are
removed.
1. Longwall Mining
• Longwall mining is a more efficient way to remove
coal form a subsurface seam.
• A machine (shearer) moves back and forth across the
face of a coal seam.
• The coal is sheared from the surface and falls on a
conveyor then transported out of the mine.
2. Solution Mining
• Soluble mineral ores can be removed by solution
mining.
• Hot water is injected into the oar and dissolves it.
• Compressed air is pumped into the dissolved ore and
lifts it to the surface.
C. Surface Mining
• Surface mining methods used when ore deposits
are located close to Earth’s surface.
• Open-pit mining is often used to mine large
quantities of near-surface
• Ore is mined downward, layer by layer.
1. Surface Coal Mining
• Overburden is rock that covers near-surface coal
seams
• 1st step is to remove and set aside the soil
• 2nd overburden is removed by heavy equipments.
• 3rd loaders enter the pit and remove the exposed
coal
• 4th once coal is removed the pit is filled with
overburden, contoured and covered with the soil
2. Quarrying
• Building stones (granite and marble) are mined in
quarries.
• Aggregates (sand, gravel, and crushed rock) are
the main products of quarrying.
3. Solar Evaporation
• Solar evaporation is the process of placing sea
water into enormous shallow ponds.
• Sun evaporates the water and increases the
concentration of sodium chloride
• This method of salt production is used in areas
that receive little rainfall and have high
evaporation rates.
• Solar evaporation is used largely in developing
countries and 30% of worlds salt comes from
solar evaporation.
D. Placer Mining
• Placer deposits are minerals that are
concentrated by wind and water into surface
deposits.
• Streams transport mineral grains to a point where
they fall to the streambed and are concentrated.
• Stream placers often occur at bends in rivers
where the current slows.
• Gold, diamonds and other heavy minerals are
mined by dredging.
E. Smelting
• Smelting is where crushed ore is melted at high
temperatures in furnaces to separate impurities
from molten metal.
• Flux bonds with impurities and separates them
from the molten metal
• Molten metal falls to the bottom of the furnace
and is recovered.
• The Slag (impurities)form a layer on the top
• Gases (sulfur dioxide) are captured so they do not
enter the environment
F. Undersea Mining
• Ocean floor contains significant mineral resources
• Cost and great waters depths at which minerals
are found are two reasons undersea mining has
not been successful.
Stop here and complete the 16.2
active reading worksheet.
16.3 Mining Regulations and Mine
Reclamation
• Because of environmental impacts of mining, it is
the most heavily regulated industries in the US.
• Reclaiming the land or returning it to its original
condition after mining is a part of every surface
coal mining operation.
A. The Environmental Impacts of Mining
• Billions of dollars are spent to clean up
abandoned mines.
1. Air and Noise Pollution
• At surface coal mines dust is produced by
removing, loading, hauling and dumping soil and
overburden.
• Dust is also produced when ore is blasted apart
• Noise is created by equipment and blasting
• Most surface mines are not located near urban
populations
• Regulations in US forbid mining operations to
allow dust or noise t exit the area being mined
2. Water Contamination
• Water resources can be negatively impacted by
mining
• Containments can wash into streams where they
can harm or kill aquatic life
• Minerals that contain a lot of sulfur and react
with water to produce dilute sulfuric acid.
3. Displacement of wildlife
• Removing soil from a surface mine site strips
away all plant life.
• With the removal of plants animals will leave the
area
• When the soil is returned to the site different
plants and animals may establish themselves.
• Dredging disturbs river bottoms and destroys
aquatic plant live.
• Disturbance of a riverbed can cause sediments to
contaminate a river for up to 10 km
4. Erosion and Sedimentation
• Excess rock from mines is dumped into large piles
called dumps.
• Running water erodes unprotected dumps and may
harm water quality and aquatic life
5. Soil Degradation
• Soil at a mine is removed from the uppermost layer
downward
• If soils is not removed and stored in separate layers
the soil may be nutrient poor when it is reclaimed.
• Soil rich in sulfur once exposed t water and oxygen
release acid.
• If acidified soil is returned to the mine site it may be
difficult for plants to grow.
6. Subsidence
• Subsidence is the sinking of regions of ground with little or
no horizontal movement.
• Can occur when pillars in a mind collapse or the mine roof
or floor fails
• Buildings, houses, roads, bridges, underground pipelines
and utilities may be damaged
7. Underground Mine Fires
• Fires in underground coal seams are one of the most
serious environmental consequences of coal mining
• Lighting, forest fires and burning trash can cause coalseams fires.
• These fires are hard to put out and often left to burn out
(which may take decades).
• They release smoke and gasses that can cause respiratory
problems.
B. Mining Regulation and Reclamation
• Mines in US are regulated by federal and state
laws
• Mining company must comply with Clean Water
Act and the Safe Drinking Water Act.
• All mining operations must comply with the
Endangered Species Act.
1. Reclamation
– Reclamation is the process of returning land to its
original or better conditions after mining is
completed.
– The Surface Mining control and Reclamation Act of
1977 (SMCRA) create a program for the regulation of
surface coal mining.
– The act set standards that minimize the effects of coal
mining on environment
2. State Regulation of Mining
– Mining companies must obtain permits before mining
– A bond forfeiture program is where a company must
post a funds (a bond) before mining project begins
– The states use the funds to reclaim the sit if the
company does not reclaim the site according to the
standards.
– State agencies are responsible for inspecting mines to
ensure compliance with environmental regulations.
– Pennsylvania has large projects to reclaim abandoned
mine lands.
Stop here and complete 16.3 active
reading worksheet.