Transcript Ch. 16 Minerals Power Point

Chapter 16
Minerals: A Non-renewable Resource
Overview of Chapter 16
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Introduction to Minerals
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Mineral Distribution and Formation
How Minerals are Found and Extracted
Environmental Impact of Minerals
An International Perspective
Increasing the Supply of Minerals
Substitution and Conservation
Introduction to Minerals
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Minerals
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Rocks
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Elements or compounds of elements that occur
naturally in Earth’s crust
Naturally formed aggregates of minerals
Examples of Minerals
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Concrete (mixture of
sand, gravel and
limestone)
Introduction to Minerals
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Examples of Minerals
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Table salt (nonmetal)
Copper (metal)
Mineral Distribution and Formation
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Abundant minerals in crust
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Scarce minerals in crust
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Aluminum and iron
Copper, chromium, and molybdenum
Distributed unevenly across globe
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If found in low abundance, mining is not
profitable
Formation of Mineral Deposits
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Result of natural processes
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Magmatic concentration
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Hydrothermal processes
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Minerals are carried and deposited by water heated
deep in earth’s crust
Sedimentation
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As magma cools heavier elements (Fe and Mg) settle
Responsible for deposits of Fe, Cu, Ni, Cr
Weathered particles are transported by water and
deposited as sediment on sea floor or shore
Evaporation
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Salts are left behind after water body dries up
Discovering Mineral Deposits
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Scientists (geologists) use a variety of
instruments and measurements
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Aerial or satellite photography
Aircraft and satellite instruments that
measure Earth’s magnetic field
Seismographs
Combine this with knowledge of how
minerals are formed
Extracting Minerals
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Surface Mining
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Mineral and energy resources are extracted
near Earth’s surface by removing soil, subsoil
and over-lying rock strata
More common because less expensive
Two kinds: open pit and strip mining
Subsurface Mining
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Mineral and energy resources are extracted
from deep underground deposits
Two kinds: shaft mine and slope mine
Extracting MineralsOpen Pit Surface Mining
Processing Minerals
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Smeltingprocess in which
ore is melted at
high temps to
separate
impurities from
the molten
metal
Environmental Impacts of Minerals
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Disturbs large area
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Uses large quantities of water
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Prone to erosion
Must pump water out of mine to keep it dry
Acid Mine Drainage (AMD)
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Pollution caused when sulfuric acid and
dissolved lead, arsenic or cadmium wash out of
mines into nearby waterways
Environmental Impacts of Refining
Minerals
Environmental Impacts of Refining
Minerals
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80% or more of mined
ore consists of
impurities- called
tailings
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Contain toxic materials
Smelting plants emit
large amounts of air
pollutants
Requires a lot of
energy (fossil fuels
combustion)
Case-In-Point Copper Basin, TN
Restoration of Mining Lands
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Goals: prevent further degradation and
erosion of land, eliminate local sources of
toxins and make land productive for
another purpose
Restoration of Mining Land
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Creative Approaches
- Wetlands
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Trap sediment and pollutants before they get
into streams, improving water quality
Expensive to create and maintain, but cost
effective compared to using lime to decrease
acidity
- Phytoremediation
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Use of specific plants to absorb and
accumulate toxic materials in soil
Great potential
Minerals: An International Perspective
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Highly developed countries rely on mineral
deposits in developing countries
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They have exhausted their own supplies
Governments in developing countries lack
financial resources to handle pollution
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Acid mine drainage
Air and water pollution
North American Consumption of
Selected Metals
Will We Run Out of Important Metals?
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Mineral Reserves
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Mineral deposits that have been identified and
are currently profitable to extract
Increasing Supply of Minerals –
Locating and Mining New Deposits
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Many known mineral deposits have not yet
been exploited
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Difficult to access
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Insufficient technology
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Ex: Malaria ridden forests of Indonesia
Ex: polar regions
Located too deep
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Ex: 10km or deeper
Increasing Supply of Minerals –
Minerals in Antarctica
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No substantial mineral deposits identified
to date
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Antarctica Treaty (1961)
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Geologists feel they will be discovered in near
future
No one owns Antarctica
Limits activity to peaceful uses (i.e. scientific
studies)
Madrid Protocol (1990)
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Moratorium on mineral exploration and
development for minimum of 50 years
Increasing Supply of MineralsMinerals from the Ocean
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May provide us with future supplies
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Extracting minerals from seawater
Mining seafloor- Manganese nodules (below)
Advance Mining and Processing
Technologies
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Special techniques to make use of large,
low-grade mineral deposits world-wide
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Currently requires a lot of energy
Biomining
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Using microorganisms to extract minerals from
low-grade ores
Finding Mineral Substitutes
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Important goal in manufacturing
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Driven by economics- cut costs!
Substitute expensive/scarce mineral
resources for inexpensive/abundant ones
Examples:
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Using plastic, glass or aluminum in place of tin
Using plastic instead of lead and steel in
telecommunications cables
Using glass fibers instead of copper wiring in
telephone cables
Mineral Conservation
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Includes reuse and recycling of existing
mineral supplies
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Reuse- using items over and over again
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Reduces both mineral consumption and pollution
Benefits greater than recycling
Recycling- converting item into new product
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Common practice throughout industrialized world
Reduces land destruction from mining
Reduces solid waste
Decreases energy consumption and pollution
Changing Our Mineral Requirements
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Must change out “throw away” mentality
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Damaged or unneeded articles are thrown away
Mineral Flow in an Industrial Society