2. Learning Competency
• The learners will be able to identify the minerals important to society
(S11ES-Ic-7).
Specific Learning Outcomes
At the end of the lesson, the learners will be able to:
• understand the importance of different minerals to society; and
• understand the different ways on how mineral deposits are formed.
3. • Mineral Occurrence – concentration of a mineral that is of scientific or
technical interest
• Mineral Deposit – mineral occurrence of sufficient size and grade or
concentration to enable extraction under the most favorable conditions
• Ore Deposit – mineral deposit that has been tested and known to be
economically profitable to mine.
• Aggregate – rock or mineral material used as filler in cement, asphalt, plaster,
etc; generally used to describe nonmetallic deposits
• Ore – naturally-occurring material from which a mineral or minerals of
economic value can be extracted
4. • Most rocks of the Earth's crust contain metals and other elements but
at very low concentrations.
• For example, the average concentration of Gold in rocks of the Earth's
crust is about 0.005 ppm (parts per million) which is roughly 5 grams
of gold for every 1000 tons of rock.
• Although valuable, extracting Gold at this concentration is not
economic (the cost of mining will be too high for the expected profit).
• Fortunately, there are naturally occurring processes (geologic
processes) that can concentrate minerals and elements in rocks of a
particular area.
5. Types of Mineral Resource
• Metallic mineral deposits: gold, silver, copper, platinum, iron
• Non-metallic resources: talc, fluorite, sulfur, sand, gravel
6. Occurrence of a Mineral Resource
• The geologic processes involved in the rock cycle play major role in
the accumulation and concentration of valuable elements/ minerals.
• Plate tectonics: the Earth’s crust is broken into a dozen or more plates
of different sizes that move relative to one another (lithosphere).
These plates are moving slowly on top of a hot and more mobile
material called the asthenosphere.
8. Mineral Resources and their
Origins
Mineral resources can be classified according to the mechanism responsible for
concentrating the valuable substance.
9. Magmatic Ore Deposits
• Valuable substances are concentrated within an igneous body
through magmatic processes such as crystal fractionation, partial
melting and crystal settling.
• Magmatic processes can concentrate the ore minerals that contain
valuable substances after accumulating elements that were once
widely dispersed and in low concentrations within the magma.
10. Magmatic Ore Deposits
Examples:
• Crystal settling: as magma cools down, heavier minerals tend to crystallize early and
settle at the lower portion of the magma chamber
• From a basaltic magma, chromite (FeCr2O4), magnetite (Fe3O4), and platinum (Pt) can be
concentrated through crystal settling
• Fractional crystallization: the residual melt contains high percentage of water and volatile
substances that are favorable for the formation of pegmatites. Pegmatites are enriched
in lithium, gold, boron, rare elements, and some other heavy metals
• Fractional crystallization of granitic magmas can concentrate rare earth elements (such as cesium
and uranium) and heavy metals. This can also form pegmatites (large crystals of quartz, feldspars,
and muscovite), which may contain semi-precious gems, such as beryl, topaz, and tourmaline
11. Hydrothermal Ore Deposits
• Concentration of valuable substances by hot aqueous (water-rich) fluids flowing through
fractures and pore spaces in rocks
• Hydrothermal solutions - are hot, residual watery fluids derived during the later stages of
magma crystallization and may contain large amount of dissolved metals. These can also
originate from the ground water circulating at depth that is being heated up by a cooling
and solidifying igneous body or along depths with known geothermal gradient.
• Such hot water can dissolve valuable substances (at low concentrations) from rocks. As
the metal enriched hot waters move into cooler areas in the crust, the dissolved
substances may start to precipitate
• There are numerous hydrothermal mineral deposits as compared to the different types
of deposits
12. Hydrothermal Ore Deposits
Examples:
1. Vein type deposits - A fairly well defined zone of mineralization,
usually inclined and discordant (cuts across existing structures) and
typically narrow. Most vein deposits occur in fault or fissure openings
or in shear zones within the country rock. Sometimes referred to as
(metalliferous) lode deposits, many of the most productive deposits of
gold, silver, copper, lead, zinc, and mercury occur as hydrothermal vein
deposits
13. Hydrothermal Ore Deposits
Examples:
2. Disseminated deposits - Deposits in which the ore minerals are
distributed as minute masses (very low concentration) through large
volumes of rocks. This occurrence is common for porphyry copper
deposits
14. Hydrothermal Ore Deposits
Examples:
3. Massive sulfide deposit (at oceanic spreading centers) - Precipitation
of metals as sulfide minerals such as sphalerite (ZnS) and chalcopyrite
(CuFeS2) occurs when hot fluids that circulated above magma
chambers at oceanic ridges that may contain sulfur, copper and zinc
come in contact with cold groundwater or seawater as it migrate
towards the seafloor.
15. Hydrothermal Ore Deposits
Examples
4. Stratabound ore deposits (in lake or oceanic sediment) – This deposit
is formed when the dissolved minerals in a hydrothermal fluid
precipitate in the pore spaces of unconsolidated sediments on the
bottom of a lake or ocean. Such minerals may contain economic
concentrations of lead, zinc, and copper, usually in sulfide form like
galena (PbS), sphalerite (ZnS), and chalcopyrite (CuFeS2).
16. Sedimentary Ore Deposits
• Some valuable substances are concentrated by chemical precipitation
coming from lakes or seawater
17. Sedimentary Ore Deposits
Examples:
• Evaporite Deposits: This type of deposit typically occurs in a closed marine
environment where evaporation is greater than water inflow. As most of the
water evaporates, the dissolved substances become more concentrated in the
residual water and would eventually precipitate.
• Halite (NaCl), gypsum (CaSO4∙2H20), borax (used in soap), and sylvite (KCl, from
which K is extracted for fertilizers) are examples of minerals deposited through this
process.
• Iron Formation: These deposits are made up of repetitive thin layers of iron-
rich chert and several other iron bearing minerals such as hematite and
magnetite. Iron formations appear to be evaporite-type deposits and are
mostly formed in basins within continental crust during the Proterozoic (2
billion years or older).
18. Placer Ore Deposits
• Deposits formed by the concentration of valuable substances through gravity separation
during sedimentary processes.
• Usually aided by flowing surface waters either in streams or along coastlines. -
Concentration would be according to the specific gravity of substances, wherein the
heavy minerals are mechanically concentrated by water currents and the less-dense
particles remain suspended and are carried further downstream.
• Usually involves heavy minerals that are resistant to transportation and weathering.
• Common deposits are gold and other heavy minerals such as platinum, diamonds, and
tin
• The source rock for a placer deposit may become an important ore body if located.
19. Residual Ore Deposits
• A type of deposit that results from the
accumulation of valuable materials
through chemical weathering
processes.
• During the process, the volume of the
original rock is greatly reduced by
leaching.
• Important factors for the formation of
residual deposit include parent rock
composition, climate (tropical and
sub-tropical: must be favorable for
chemical decay), and relief (must not
be high to allow accumulation)
Relief - the configuration of an area that pertains to the
elevation and slope variations and the irregularities of
the land surface
20. Residual Ore Deposits
• Common deposits are bauxites and nickeliferous laterites.
• Bauxite, the principal ore of aluminum, is derived when aluminum-rich source rocks undergo
intense chemical weathering brought by prolonged rains in the tropics, leaching the common
elements that include silicon, sodium and calcium through leaching.
• Nickeliferous laterites or nickel laterites are residual ore deposits derived from the
laterization of olivine-rich ultramafic rocks such as dunite and peridotite. Like in the
formation of bauxite, the leaching of nickel-rich ultramafic rocks dissolves common elements,
leaving the insoluble nickel, magnesium and iron oxide mixed in the soil.
• Laterization - conditions of weathering which leads to the removal of alkalis and silica,
resulting in a soil or rock with high concentrations of iron and aluminum oxides.
• Secondary Enrichment Deposits are derived when a certain mineral deposit becomes enriched
due to weathering.
21. Assignment (Group Work,
handwritten/printed/PowerPoint) - to be reported
on Friday, 8 mins per group
Group 1: computer monitor Group 4: computer chip
Group 2: computer circuitry Group 5: computer case
Group 3: electrical cords
Prepare a short report about the designated component of the computer. Report should answer the following:
• Identify the minerals and metals used to build the computer component
• Identify the properties of each mineral/metal that makes it useful to the function of that computer part.
• Select one specific mineral/metal from the computer part. Discuss how the mineral is formed (what are the ore
minerals and the most realistic origin of the ore resource)
• Based on the list, hypothesize what minerals would be useful for another electronic item (television, media player,
mobile phone, etc.)
• Discuss environmental implications of disposing outdated computer equipment. Should it be landfilled? Why is
computer waste one of the biggest waste issues facing the world? Discuss the global implications of computer
waste.
