Transcript ch. 15 minerals - OCPS TeacherPress

CHAPTER 15
MINERALS: A NON-RENEWABLE RESOURCE
Overview of Chapter 15

Introduction to Minerals
 Mineral
Distribution and Formation
 How Minerals are Found and Extracted
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Environmental Impact of Minerals
An International Perspective
Increasing the Supply of Minerals
Substitution and Conservation
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http://www.youtube.com/watch?v=RPixjCneseE&fe
ature=related
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http://www.youtube.com/watch?v=GZoQ5Gw0r7
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Introduction to Minerals

Minerals
 Elements
or compounds of elements that occur naturally
in Earth’s crust

Rocks
 Naturally

formed mixtures of minerals
Ore – rock with large amount of mineral
Introduction to Minerals

Examples of Minerals
 Nonmetal:
salt, sand, stone
 Metal: copper, aluminum, iron
Mineral Distribution

Abundant minerals in crust
 Aluminum

and iron
Distributed unevenly across globe
 If
found in low abundance, mining is not profitable
Mineral Distribution



US imports over 50% of its most needed
Depleted reserves leads to mining of lower grades
which needs more processing and produces more
pollution
Examples of distribution of global reserves
 Oil:
Middle East
 Natural Gas: Middle East
 Coal (largest source of fuel for electricity): China
 Diamonds - Africa
 Gold – S. Africa
 Six
tons of waste to make 2 gold rings
Formation of Mineral Deposits

Result of natural processes
 Magmatic
concentration (igneous)
 As
magma cools heavier elements (Fe and Mg) settle
 Responsible for deposits of Fe, Cu, Ni, Cr
 Hydrothermal
processes
 Minerals
are carried and deposited by water heated deep
in earth’s crust
 Sedimentation
 Weathered
particles are transported by water and
deposited as sediment on sea floor or shore
 Evaporation
 Salts
are left behind after water body dries up
Extracting Minerals

Surface Mining
 Remove
overlying soil/rock (overburden) and then
scoop out minerals
 More common because less expensive
 Two kinds: open pit and strip mining (ex: mountain top
removal for coal)

Subsurface Mining
 Mineral
and energy resources are extracted from deep
underground deposits
 Two kinds: shaft mine and slope mine
 Disturbs land less, more expensive, more dangerous
Extracting MineralsOpen Pit Surface Mining
Relevant laws

Surface Mining Control and Reclamation Act
(1977) – requires reclamation of land mined for
coal
Reclaiming of Mining lands

Reclaim to semi-natural state
 Prevent
further erosion
 Control source of toxic pollutants
 Giving purpose to land other than mining
Reclaiming of Mining Land

Creative Approaches
-
Wetlands
 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
 Use
of specific plants to absorb and accumulate toxic
materials in soil
 Great potential
Environmental issues

Toxic heavy metals: tailings - wastes after processing, toxic
(cyanide, mercury, sulfuric acid) – pollute air, soil, water

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Acid mine drainage
Smelting – air pollution, mainly sulfur emitted, reacts with
oxygen to form sulfur dioxide which reacts with water form to
sulfuric acid. Also, cadmium (cancer), lead (neurotoxin) into air
Massive energy usage – mostly fossil fuels (depletes reserves
and produces CO2)
Massive water usage
Destroys vegetation

habitat loss, erosion
Processing Minerals

Smelting- process in
which ore is melted
at high temps to
separate impurities
from the molten
metal
Environmental Impacts of Refining Minerals
Will We Run Out of Important Metals?

Mineral Reserves
 Mineral
deposits that have been identified and are
currently profitable to extract
Mineral Conservation

Includes reuse and recycling of existing mineral
supplies
 Reuse-
using items over and over again
 Reduces
both mineral consumption and pollution
 Benefits greater than recycling – less energy inputted
 Recycling Common
converting item into new product
practice throughout industrialized world
 Reduces land destruction from mining
 Reduces solid waste
 Decreases energy consumption and pollution
North American Consumption of Selected Metals
Changing Our Mineral Requirements

Must change out “throw away” mentality
 Damaged
or unneeded articles are thrown away
Minerals: An International Perspective

Highly developed countries rely on mineral deposits
in developing countries
 They

have exhausted their own supplies
Governments in developing countries lack financial
resources to handle pollution
 Acid
mine drainage
 Air and water pollution
Increasing Supply of Minerals –
Locating and Mining New Deposits

Many known mineral deposits have not yet been
exploited
 Difficult
 Ex:
to access
Malaria ridden forests of Indonesia
 Insufficient
 Ex:
polar regions
 Located
 Ex:
technology
too deep
10km or deeper
Increasing Supply of Minerals –
Minerals in Antarctica

No substantial mineral deposits identified to date
 Geologists
feel they will be discovered in near future
 No one owns Antarctica

Antarctica Treaty (1961)
 Limits

activity to peaceful uses (i.e. scientific studies)
Madrid Protocol (1990)
 Moratorium
on mineral exploration and development
for minimum of 50 years
Increasing Supply of MineralsMinerals from the Ocean

May provide us with future supplies
 Extracting
minerals from seawater
 Mining seafloor- Manganese nodules (below)
Advance Mining and Processing Technologies

Special techniques to make use of large, low-grade
mineral deposits world-wide
 Currently

requires a lot of energy
Biomining
 Using
microorganisms to extract minerals from lowgrade ores
Finding Mineral Substitutes

Important goal in manufacturing
 Driven


by economics- cut costs!
Substitute expensive/scarce mineral resources for
inexpensive/abundant ones
Examples:
 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 Flow in an Industrial Society