Mineral%20resources

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Mineral resources

• Mineral resources are

• Minerals or rocks mined from the earth and used
  in the products we use daily.
• Coal, oil, and natural gas are also mined, but
  these energy resources will be considered
  separately.

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The use of minerals and rocks in products

• Sometimes actual minerals and rocks are used in
  products or to make things. The rock granite is
  mined to make countertops, and the mineral halite
  is mined, crushed, and sold as table salt.
• Other times, minerals and brines are processed to
  extract one specific element, and these
  individual elements are often called mineral
  commodities. For example, the commodity aluminum
  is extracted from the rock bauxite, which
  contains aluminum-bearing minerals like gibbsite.
  
• The process of extracting the desired mineral or
  element from an ore is called beneficiation.

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Minerals

• Minerals are

• solid
• inorganic (or identical to an inorganic mineral)
• natural (or made in a way that mimics nature)
• chemically homogeneous (that is, the mineral
  contains the same chemicals throughout)
• crystalline (the atoms in a mineral are arranged
  in an orderly and repeating pattern)

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Examples of minerals
Mineral Quartz Hematite Diamond Halite
Chemical formula SiO2 Fe2O3 C NaCl
Elements in these minerals Si silicon, O oxygen (two oxygen atoms for every one silicon atom) Fe iron, O oxygen (two iron atoms for every three oxygen atoms) C carbon Na sodium, Cl chlorine
Crystal structures  
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NOT minerals
The "minerals" in these vitamins and minerals
are not real minerals. These are elements that
may have been extracted from minerals.
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Common elements and common minerals

• Minerals are comprised of elements.
• Eight elements make up the majority of Earth's
  crust and mantle

Whats within the crust (by mass)
Elements in the crust Mass
Oxygen (o) 46.6
Silicon (Si) 27.72
Aluminum (Al) 8.13
Iron (Fe) 5.00
Calcium (Ca) 3.63
Sodium (Na) 2.83
Potassium (K) 2.59
Magnesium (Mg) 2.09
Common metals (Al,Fe,Ca, Na, K, Mg)
All others
Oxygen
Silicon
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Common elements and common minerals

• These elements can combine in a variety of ways
  to make different minerals.
• Most minerals contain silicon and oxygen (plus
  other elements). These minerals are called
  silicate minerals.

Crystal structure of almandine garnet (Fe3 Al2
Si3 O12 ) containing iron and aluminum in
addition to silicon and oxygen.
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Common elements and common minerals

• Why do we care about this?
• Sustainability The eight elements just listed
  are the most plentiful. Other elements are more
  rare we find them less frequently and have a
  lower overall supply of them.
• Ease of use Silicate minerals tend to be
  refractory they have high melting points and low
  solubilities, so they hold onto the elements
  within them.
• Although the majority of Earths elements are
  found in silicate minerals, they are usually
  found in higher quantities in nonsilicate
  minerals, commonly oxide or sulfide minerals. It
  is more efficient to mine elements when they are
  found in higher concentrations.

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If we want the element in the mineral (and not
the mineral itself), then we seek nonsilicate
minerals that contain the element, because it is
easier (fewer resources are needed) to extract
those elements from the mineral. For example,
although the silicate mineral fayalite (Fe2SiO4)
contains iron (Fe), it is easier and more
efficient to extract iron from hematite (Fe2O3),
which is a nonsilicate mineral.
Fayalite. Not an economic source for iron,
though it contains iron.
Hematite. Iron is commonly extracted from this
mineral.
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Mineral properties

• A mineral's chemical and crystalline nature gives
  it properties that make it useful.
• These properties also must be considered when
  determining how best to mine, process, and
  dispose of the mineral and mine waste.

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Mineral properties Chemistry

• The elements within minerals give them distinct
  and useful properties.

• For example
• Sulfur allows gunpowder to ignite at a lower
  temperature and provides fuel for the fire.

Sulfur can be found as a mineral (native sulfur,
S)
Sulfur can also exist as an element within other
minerals like pyrite (FeS).
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Mineral properties Chemistry
Aluminum alloys were extensively used for
constructing Apollo 16 whose Command and Service
Module (CSM) "Casper" is shown here

• For example
• Aluminum metal is very lightweight but strong.

Aluminum does not form a mineral on its own, but
is beneficiated from the minerals gibbsite and
bohemite.
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Mineral properties Hardness

• A mineral's hardness is determined by
• The crystalline nature of that mineral,
• The type and strength of bonds that hold the
  atoms together, and,
• The nature of the repeating pattern

Both graphite and diamond are made up of the same
element, carbon (C). However, diamond is much
harder than graphite.
Crystal structure for graphite
Crystal structure for diamond
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Mineral properties Hardness

• For example
• Very hard minerals (like diamond, corundum, and
  garnet) are useful as abrasives. Saw blades
  impregnated with diamonds can cut rock, and
  sandpaper is often made with garnet sand.

Almandine garnet crystals. Hardness of almandine
garnet is 78 On the Mohs scale of hardness
Talc (hardness 1 on the Mohs scale of
hardness) is used in baby powder because it is a
very soft mineral.
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Mineral properties Color

• Some minerals have distinct, and vibrant, colors.
  This makes them incredibly useful as pigments in
  paints, cosmetics, colored plastic, etc.

The rust red color of hematite (left) and rust
yellow color of limonite ( a variety of goethite,
right) have long been used as a pigment.
Malachites green color has made it useful in
paints
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Mineral properties Color
For example The native people in Himba Village,
Namibia, powder iron oxide minerals (like
hematite and goethite) to color their skin and
hair.
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Mineral properties Specific gravity

• Specific gravity is a relative density,
  determined both by a mineral's chemistry
  (minerals containing heavier elements will have
  higher specific gravities) and how closely
  together the atoms are packed.

Galena (PbS) contains the heavy element lead,
giving it a high specific gravity
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Mineral properties Behavior of light in the
crystal

• The crystalline structure determines if and how
  light passes through a mineral. For example,
  light reflects inside of diamond, which gives
  diamond ring an exquisite sparkle.
• Other minerals (like rutile) are quite opaque,
  which makes titanium oxide (the chemical name of
  rutile) an important additive in things that need
  to be opaque, like paint.
• Some minerals are also useful in blocking other
  wavelengths of light barite and lead (from the
  mineral galena) block X-rays, for example.

The crystalline structure of calcite (Iceland
spar variety) can split light rays passing
through it, making the horizontal lines seen
through the calcite crystal appear to double up
in this photo. Iceland Spar crystals were once
used in polarizing microscopes and telescopes
because of this property.
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Mineral properties Luster

• Luster describes how light interacts with the
  surface of a mineral.
• For example, the mineral hematite can have both
  metallic or nonmetallic luster hematite with
  metallic luster (photo on left) is used to make
  jewelry.

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Mineral properties Crystal shape and cleavage

• These are determined by the nature of the
  crystalline structure. The sheet-like cleavage of
  muscovite allows it to be broken into tiny pieces
  of glitter.

Muscovites cleavage causes it to break into
sheets.
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Mineral properties Solubility

• Different minerals dissolve differently depending
  on their crystalline structure (the type of
  bonds) and chemistry. When a mineral dissolves,
  it breaks into the ions that it contains.
• Some dissolve quickly in water (or acidic or
  alkali solutions), whereas others are very
  stable.

For example, people eat tablets made of calcite
that calcite dissolves in the stomach,
neutralizing some of the acid and reducing
heartburn
TUMS tablet dissolving in acidic water releasing
bubbles of carbon dioxide.
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Mineral properties Solubility

• For some applications, an insoluble mineral is
  preferred. For example, the Eads Bridge that
  crosses the Mississippi River is faced with rock
  made of insoluble minerals below the water line,
  whereas more decorative limestone (made of the
  more soluble mineral calcite) faces the support
  above the water line.
• If a mineral is being mined from the element it
  contains, then it will be easier to extract that
  element from a soluble mineral.

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Mineral properties Magnetism

• The chemistry of certain minerals allows them to
  store an applied magnetic field. For example,
  magnetic minerals in a hard drive can be
  programmed to store information.

A bar magnet hanging from a sample of magnetite.
Magnetite is an iron oxide (Fe3O4), and is
naturally magnetic.
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Mineral properties Electrical conductivity

• Electrical conductivity is mainly determined by
  the presence of metallic bonds. Metals have these
  bonds, which is why metals are favored for wires.

Coppers electrical conductivity and resistance
to corrosion make it ideal for electric wiring.
Copper can be found as a pure metal (native
copper, Cu)
Copper is often beneficiated from minerals like
chalcopyrite (CuFeS2).
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Mineral properties Electrical conductivity

• Minerals that have low electric conductivity will
  be used for insulators, which block and/or
  confine the electric current.

Clay minerals such as kaolinite show very low
electrical and thermal conductivity.
Ceramic insulators made from clay minerals are
used for supporting electric power lines
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Mineral properties Thermal conductivity

• Minerals can also be used to conduct or confine
  heat. Thermal conductivity is determined by both
  a minerals chemistry and crystalline structure

Ceramic kitchen utensils made from clay minerals
are used to confine the temperature of food and
beverages
Clay minerals such as kaolinite show very low
electrical and thermal conductivity.
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Mineral properties Melting point

• Different minerals melt at different
  temperatures. Minerals with high melting points
  are used for high-temperature applications.

For example, the mineral graphite is used for
lining furnaces and as crucibles for melting
metals
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Mineral properties Response to stress
Different minerals/rocks behave differently under
stress. For example, while many minerals will
shatter if hit with a hammer, gold is malleable.
This allowed early people to easily shape it into
ornaments.

• Piezoelectricity is another property related to
  stress. An electric current is generated in
  piezoelectric minerals when a stress is applied.
• For example, a hammer hits a piezoelectric
  crystal, and this will generate a spark to ignite
  a cigarette lighter. The piezoelectricity of
  quartz allows it to be used to tell time (in
  quartz crystal watches), and piezoelectricity is
  also useful in transformers and motors.