Geology and Nonrenewable Mineral Resources Chapter 14 Iron Ore

Geology and Geology and Nonrenewable Mineral Nonrenewable Mineral

ResourcesResources

Chapter 14Chapter 14

Iron Ore

Chapter Overview QuestionsChapter Overview Questions

What major What major geologic processesgeologic processes occur within occur within the earth and on its surface?the earth and on its surface?

What are What are nonrenewable mineral resourcesnonrenewable mineral resources and where are they found?and where are they found?

What are What are rocksrocks, and how are they recycled , and how are they recycled by the by the rock cyclerock cycle??

How do we How do we find and extractfind and extract mineral mineral resources from the earth’s crust, and what resources from the earth’s crust, and what harmful environmental effectsharmful environmental effects result from result from removing and using these minerals?removing and using these minerals?

Chapter Overview Questions (cont’d)Chapter Overview Questions (cont’d)

Will there be enough nonrenewable mineral Will there be enough nonrenewable mineral resources for resources for future generationsfuture generations??

Can we find Can we find substitutessubstitutes for scarce for scarce nonrenewable mineral resources?nonrenewable mineral resources?

How can we shift to How can we shift to more sustainable usemore sustainable use of of nonrenewable mineral resources?nonrenewable mineral resources?

GEOLOGIC PROCESSESGEOLOGIC PROCESSES The earth is made up of a core, mantle, and The earth is made up of a core, mantle, and

crust and is crust and is constantly changingconstantly changing as a result as a result of processes taking place on and below its of processes taking place on and below its surface.surface.

The earth’s interior consists of:The earth’s interior consists of: CoreCore: innermost zone with solid inner core and : innermost zone with solid inner core and

molten outer core that is extremely hot.molten outer core that is extremely hot. MantleMantle: mostly solid rock with a rigid outer part : mostly solid rock with a rigid outer part

(asthenosphere) that is melted pliable rock.(asthenosphere) that is melted pliable rock. CrustCrust: Outermost zone which underlies the : Outermost zone which underlies the

continents.continents.

Fig. 15-3, p. 337

Spreading center Ocean

trench

Plate movement

Subduction zone

Oceanic crust

Continental crust

Continental crust

Material cools as it reaches

the outer mantle

Cold dense material falls back through

mantleHot

material rising

through the

mantle

Mantle convection

cell

Two plates move towards each other. One is subducted back into the mantle on a falling convection current.

Mantle

Hot outer core Inner

core

Plate movement

Collision between two continents

Tect

onic

pl

ate

Oceanic tectonic

plate

Oceanic tectonic plate

Oceanic crust

GEOLOGIC PROCESSESGEOLOGIC PROCESSES

Major features of the earth’s Major features of the earth’s crustcrust and and upper upper mantle.mantle.

nextnext

Fig. 15-2, p. 336

Volcanoes

Folded mountain belt

Abyssal floor

Oceanic ridge

Abyssal floor TrenchAbyssal hills

Craton

Abyssal plain

Oceanic crust (lithosphere)

Continental Continental shelfshelf

Aby

ssal

pla

in

Continental slope

Continental rise

Continental crust (lithosphere) Mantle (lithosphere)

Mantle (lithosphere)

Mantle (asthenosphere)

Fig. 15-4a, p. 338

EURASIAN PLATEEURASIAN PLATENORTH NORTH AMERICAN AMERICAN PLATEPLATE

ANATOLIAN ANATOLIAN PLATEPLATE

JUAN DE JUAN DE FUCA PLATEFUCA PLATE

CHINA CHINA SUBPLATESUBPLATE

CARIBBEAN CARIBBEAN PLATEPLATE

PHILIPPINE PHILIPPINE PLATEPLATE

ARABIAN ARABIAN PLATEPLATEAFRICAN AFRICAN

PLATEPLATEPACIFIC PACIFIC PLATEPLATE SOUTH SOUTH

AMERICAN AMERICAN PLATEPLATENAZCA NAZCA

PLATEPLATEINDIA-INDIA-

AUSTRALIAN AUSTRALIAN PLATEPLATE

SOMALIAN SOMALIAN SUBPLATESUBPLATE

ANTARCTIC PLATEANTARCTIC PLATE

Divergent plate boundaries

Convergent plate boundaries

Transform faults


Huge volumesHuge volumes of of heated and molten rockheated and molten rock moving around the earth’s interior form moving around the earth’s interior form massive solid platesmassive solid plates that move extremely that move extremely slowly across the earth’s surface.slowly across the earth’s surface.

Tectonic platesTectonic plates: huge rigid plates that are : huge rigid plates that are moved with moved with convection cellsconvection cells or or currentscurrents by by floating on floating on magmamagma or molten rock. or molten rock.

Tectonic plates move at approximately the same Tectonic plates move at approximately the same speed that fingernails grow.speed that fingernails grow.

The Earth’s Major Tectonic PlatesThe Earth’s Major Tectonic Plates

The extremely slow movements of these The extremely slow movements of these plates cause them to grind into one another plates cause them to grind into one another at at convergent plate boundariesconvergent plate boundaries, move apart , move apart at at divergent plate boundariesdivergent plate boundaries and slide past and slide past at at transform plate boundariestransform plate boundaries..

Figure 15-4Figure 15-4

Fig. 15-4b, p. 338

Trench Volcanic island arc Craton

Transform fault

LithosphereSubduction zone

Lithosphere Lithosphere

Asthenosphere Asthenosphere Asthenosphere

Divergent plate boundaries Convergent plate boundaries Transform faults

a.k.a. transform plate boundaries

Rising magma

Fig. 15-4, p. 338

Fig. 15-4a, p. 338

EURASIAN PLATEEURASIAN PLATENORTH NORTH AMERICAN AMERICAN PLATEPLATE

ANATOLIAN ANATOLIAN PLATEPLATE

JUAN DE JUAN DE FUCA PLATEFUCA PLATE

CHINA CHINA SUBPLATESUBPLATE

CARIBBEAN CARIBBEAN PLATEPLATE

PHILIPPINE PHILIPPINE PLATEPLATE

ARABIAN ARABIAN PLATEPLATEAFRICAN AFRICAN

PLATEPLATEPACIFIC PACIFIC PLATEPLATE SOUTH SOUTH

AMERICAN AMERICAN PLATEPLATENAZCA NAZCA

PLATEPLATEINDIA-INDIA-

AUSTRALIAN AUSTRALIAN PLATEPLATE

SOMALIAN SOMALIAN SUBPLATESUBPLATE

ANTARCTIC PLATEANTARCTIC PLATE

Divergent plate boundaries

Convergent plate boundaries

Transform faults


The San The San Andreas Fault is Andreas Fault is an example of a an example of a transform faulttransform fault..


GEOLOGIC PROCESSESGEOLOGIC PROCESSESExternal processes result directly or indirectly from solar energy and on gravity.

•Wind, rain, weathering, erosion

•Tend to wear the earth’s surface down and produce a variety of landforms formed by eroded topsoil, sand, and sediment.

Hoodoos at Bryce Canyon, UT


“Hoodoos at Sunrise” Bryce Canyon, UT



Internal processes tend to build up the earth’s surface

Cleveland Volcano

Chuginadak Island, Alaska


Sarychev Volcano

Kuril Island, Japan (Between Japan & Russia)


Sarychev Volcano

View from the International Space Station

GEOLOGIC PROCESSESGEOLOGIC PROCESSESInternal processes tend to build up the earth’s surface

Wearing Down and Building Up the Wearing Down and Building Up the Earth’s SurfaceEarth’s Surface

WeatheringWeathering is is an external an external process that process that wears the wears the earth’s earth’s surface surface down.down.

NextNext

Fig. 15-6, p. 340

Parent material (rock)

Biological weathering (tree roots and lichens)

Chemical weathering (water, acids, and gases)

Physical weathering (wind, rain, thermal expansion and contraction, “frost wedging”: water freezing and expanding)

Particles of parent material

MINERALS, ROCKS, AND THE MINERALS, ROCKS, AND THE ROCK CYCLEROCK CYCLE

The earth’s crust consists of The earth’s crust consists of solid inorganic solid inorganic elements and compoundselements and compounds called called mineralsminerals that can sometimes be used as resources.that can sometimes be used as resources.

Mineral resourceMineral resource: a concentration of naturally : a concentration of naturally occurring material occurring material in or on the earth’s crustin or on the earth’s crust that that can be can be extracted and processedextracted and processed into useful into useful

materials at an materials at an affordable costaffordable cost..

Fig. 15-7, p. 341

Undiscovered Identified

Reserves

Eco

no

mic

al

Other resources

Dec

reas

ing

co

st o

f ex

trac

tio

n

No

t ec

on

om

ical

Decreasing certainty Known

Existence

General Classification of General Classification of Nonrenewable Mineral ResourcesNonrenewable Mineral Resources

The The U.S. Geological SurveyU.S. Geological Survey classifies classifies mineral resources into mineral resources into four major categoriesfour major categories:: IdentifiedIdentified: known location, quantity, and quality : known location, quantity, and quality

or existence known based on direct evidence and or existence known based on direct evidence and measurements.measurements.

UndiscoveredUndiscovered: potential supplies that are : potential supplies that are assumed to exist based on indirect evidence.assumed to exist based on indirect evidence.

ReservesReserves: identified resources that can be : identified resources that can be extracted profitably.extracted profitably.

Other: undiscovered or identified resources not Other: undiscovered or identified resources not classified as reservesclassified as reserves

General Classification of General Classification of Nonrenewable Mineral ResourcesNonrenewable Mineral Resources

3 Major Categories3 Major Categories fossil fuelsfossil fuels (coal, oil, natural gas) (coal, oil, natural gas)

metallic mineralsmetallic minerals (copper, iron, platinum, etc.) (copper, iron, platinum, etc.)

nonmetallic mineralsnonmetallic minerals (sand, gravel, (sand, gravel, limestone).limestone).


GEOLOGIC PROCESSESGEOLOGIC PROCESSES Deposits of nonrenewable mineral resources in Deposits of nonrenewable mineral resources in

the earth’s crust the earth’s crust varyvary in their in their abundance and abundance and distributiondistribution..

5 nations supply most of the world’s nonrenewable 5 nations supply most of the world’s nonrenewable mineral resourcesmineral resources• USA, Canada, Russia, South Africa, AustraliaUSA, Canada, Russia, South Africa, Australia

3 nations (8% of world pop.) use 75% of metals3 nations (8% of world pop.) use 75% of metals• USA, Germany, RussiaUSA, Germany, Russia

Mineral ResourcesMineral Resources USA:USA: Imports 50% or more of Imports 50% or more of 24 of its 42 most important24 of its 42 most important

nonrenewable mineral resourcesnonrenewable mineral resources The “strategic four”:The “strategic four”:

• Chromium, Cobalt, Manganese, PlatinumChromium, Cobalt, Manganese, Platinum• Essential for Essential for economy & militaryeconomy & military “…no cars, airplanes, “…no cars, airplanes,

jet engines, satellites, sophisticated weapons, or jet engines, satellites, sophisticated weapons, or household appliances without these 4”household appliances without these 4”

• US has virtually US has virtually no reservesno reserves• Depend on Depend on politically unstablepolitically unstable sources in former sources in former

Soviet Republics and in Africa (South Africa, Zambia, Soviet Republics and in Africa (South Africa, Zambia, Zimbabwe, Republic of Congo)Zimbabwe, Republic of Congo)

• US has a US has a 3 year strategic reserve3 year strategic reserve

GEOLOGIC PROCESSESGEOLOGIC PROCESSES A very slow A very slow chemical cyclechemical cycle recycles three types of recycles three types of

rock found in the earth’s crust:rock found in the earth’s crust:

Sedimentary rockSedimentary rock (sandstone, limestone). (sandstone, limestone).• Form from Form from sedimentssediments

Igneous rockIgneous rock (granite, pumice, basalt, obsidian). (granite, pumice, basalt, obsidian).• Form from Form from magmamagma or or lavalava

Metamorphic rockMetamorphic rock (slate, marble, quartzite). (slate, marble, quartzite).• Form from other rocks that Form from other rocks that changechange under extreme temperature and under extreme temperature and

pressurepressure


Sedimentary rockSedimentary rock sandstonesandstone

GEOLOGIC PROCESSESGEOLOGIC PROCESSESSedimentary rockSedimentary rock

limestonelimestone

((from CaCOfrom CaCO3 3 shells)shells)

Road Base

Most Caves

Geologic ProcessesGeologic Processes

Igneous rock:Igneous rock: granite granite


Igneous rock:Igneous rock: pumice pumice

(fast cool)(fast cool)


Igneous rock:Igneous rock: basalt basalt

(fast to medium-time cool)(fast to medium-time cool)


Igneous rock:Igneous rock: obsidian obsidian

(slow cool)(slow cool)


Metamorphic rockMetamorphic rock: slate: slate


Metamorphic rockMetamorphic rock: marble: marble

GEOLOGIC PROCESSESGEOLOGIC PROCESSESMetamorphic rock:Metamorphic rock:

quartzitequartzite

Fig. 15-8, p. 343

Erosion

Transportation

Weathering

Deposition

Igneous rock Granite, pumice, basalt, obsidian

Sedimentary rock Sandstone, limestone,mudstone Heat, pressure

Cooling

Heat, pressure, stress

Magma (molten rock)

Melting

Metamorphic rock Slate, marble, gneiss, quartzite, some “granite”

ENVIRONMENTAL EFFECTSENVIRONMENTAL EFFECTS The The extractionextraction, , processingprocessing, and , and useuse of of

mineral resources has a mineral resources has a large large environmental impact.environmental impact.

MOSTMOST global & U.S. global & U.S. solid wastesolid waste comes comes from extraction & processing of mineral from extraction & processing of mineral resourcesresources


Surface mining

Metal ore Separation of ore from gangue

Smelting Melting metal

Conversion to product

Discarding of product (scattered in environment)

Recycling

What happens to matter quality if metal is scattered in the environment?

What is required for metal to be recycled?

Good news: Metal is infinitely recyclable, as long as there is enough energy.

Fig. 15-10, p. 344

Natural Capital Degradation

Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources

StepsSteps Environmental effectsEnvironmental effects

MiningDisturbed land; mining accidents; health hazards, mine waste dumping, oil spills and blowouts; noise; ugliness; heat

Exploration, extraction

ProcessingSolid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat

Transportation, purification, manufacturing

UseNoise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat

Transportation or transmission to individual user, eventual use, and discarding

ENVIRONMENTAL EFFECTS OF ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCESUSING MINERAL RESOURCES

Minerals are removed through a variety of Minerals are removed through a variety of methods that methods that vary widelyvary widely in their in their costscosts, , safety safety factorsfactors, and levels of , and levels of environmental harmenvironmental harm..

A variety of methods are used based on A variety of methods are used based on mineral depthmineral depth.. Surface miningSurface mining: shallow deposits are removed.: shallow deposits are removed. Subsurface miningSubsurface mining: deep deposits are removed.: deep deposits are removed.

Open-pit MiningOpen-pit Mining

Machines dig Machines dig holes and holes and remove ores, remove ores, sand, gravel, sand, gravel, and stone.and stone.

Toxic Toxic groundwatergroundwater can can accumulate at accumulate at the bottom.the bottom.

NextNext

Copper Mine, Bingham, UT

World’s largest man-made hole 0.5 mi deep, 2.5 mi wide at top


Contour Strip MiningContour Strip Mining

Used on Used on hilly or hilly or mountainousmountainous terrain.terrain.

Unless the land is Unless the land is restored, a restored, a wall of wall of dirtdirt is left in front is left in front of a of a highly highly erodible bankerodible bank called a called a highwallhighwall..

NextNext

Fig. 15-13, p. 346

Undisturbed land

Overburden

Highwall Coal seam Overburden Pit

Bench

Coal seam

Spoil banks

Area Strip MiningArea Strip Mining

Earth movers Earth movers strips away strips away overburdenoverburden, and , and giant shovels giant shovels removes mineral removes mineral deposit.deposit.

Often leaves highly Often leaves highly erodible hills of erodible hills of rubble called rubble called spoil spoil banksbanks..


Mountaintop RemovalMountaintop Removal

Machinery Machinery removes the tops removes the tops of mountainsof mountains to to expose coal.expose coal.

The resulting The resulting waste rock and waste rock and dirt (“tailings”) are dirt (“tailings”) are dumped into the dumped into the streams and streams and valleys belowvalleys below..

NextNext

Mountaintop RemovalMountaintop Removal


Mining ImpactsMining Impacts

Metal ores are Metal ores are smeltedsmelted at high at high temperatures or temperatures or treated with treated with (potentially toxic) (potentially toxic) chemicalschemicals to extract to extract the desired metal.the desired metal. Cyanide heap Cyanide heap

leaching of goldleaching of gold


SUPPLIES OF MINERAL SUPPLIES OF MINERAL RESOURCESRESOURCES

The The future supplyfuture supply of a resource depends on of a resource depends on its its affordable supplyaffordable supply and how and how rapidly that rapidly that supply is used.supply is used.

A A rising pricerising price for a scarce mineral resource for a scarce mineral resource can can increase suppliesincrease supplies and and encourage more encourage more efficient use.efficient use.

....(stock and flows?)....(stock and flows?)


Depletion curvesDepletion curves for a renewable for a renewable resource using resource using three sets of three sets of assumptionsassumptions. . Dashed vertical Dashed vertical

lines represent lines represent times when times when 80% 80% depletiondepletion occurs. occurs.


Fig. 15-16, p. 348

A Mine, use, throw away; no new discoveries; rising prices

Recycle; increase reserves by improved mining technology, higher prices, and new discoveriesB

Pro

du

ctio

n

Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveriesC

Present Depletion time A

Depletion time B

Depletion time C

Time

SUPPLIES OF MINERAL RESOURCESSUPPLIES OF MINERAL RESOURCES New technologiesNew technologies can increase the mining can increase the mining

of of low-grade oreslow-grade ores at at affordable pricesaffordable prices, but , but harmful environmental effects can limit harmful environmental effects can limit this approach.this approach. 19001900- Average US copper ore was 5% Cu- Average US copper ore was 5% Cu 20072007- - “ “ “ “ is 0.5 % “ “ “ “ is 0.5 %

Cu, and the price of copper is lower.Cu, and the price of copper is lower.


Most Most minerals in seawaterminerals in seawater and on the and on the deep deep ocean floorocean floor cost too muchcost too much to extract, and to extract, and there are there are squabbles over who owns themsquabbles over who owns them..

““Manganese Nodules”Manganese Nodules” cover 25-50% of the cover 25-50% of the Pacific Ocean floor.Pacific Ocean floor. High costs of extraction: 4-6 km deepHigh costs of extraction: 4-6 km deep Squabbles over who owns them in international Squabbles over who owns them in international

waterswaters

““Manganese Nodules” Manganese Nodules” a.k.a. Polymetallic Nodulesa.k.a. Polymetallic Nodules

““Manganese Nodules” a.k.a. Manganese Nodules” a.k.a. Polymetallic NodulesPolymetallic Nodules

Vary in size from Vary in size from tiny particlestiny particles to to large pelletslarge pellets more more than 20 centimeters across. than 20 centimeters across.

Most nodules are between Most nodules are between 5 and 10 cm5 and 10 cm in diameter, in diameter, about the size of about the size of potatoespotatoes. .

Those of Those of greatest economic interestgreatest economic interest contain contain manganese (27-30 %), nickel (1.25-1.5 %), copper manganese (27-30 %), nickel (1.25-1.5 %), copper (1-1.4 %) and cobalt (0.2-0.25 %). Other (1-1.4 %) and cobalt (0.2-0.25 %). Other constituents include iron (6 %), silicon (5%) and constituents include iron (6 %), silicon (5%) and aluminium (3%), with lesser amounts of calcium, aluminium (3%), with lesser amounts of calcium, sodium, magnesium, potassium, titanium and sodium, magnesium, potassium, titanium and barium, along with hydrogen and oxygen. barium, along with hydrogen and oxygen.

Getting More Minerals from the Getting More Minerals from the OceanOcean

Hydrothermal Hydrothermal depositsdeposits form when form when mineral-rich mineral-rich superheated water superheated water shoots out of shoots out of ventsvents in solidified magma in solidified magma on the ocean floor.on the ocean floor.


USING MINERAL RESOURCES USING MINERAL RESOURCES MORE SUSTAINABLYMORE SUSTAINABLY

Scientists and engineers are developing new Scientists and engineers are developing new types of materials as types of materials as substitutessubstitutes for many for many metals (see metals (see nanotechnologynanotechnology p.335 & S-33) p.335 & S-33)

RecyclingRecycling valuable and scarce metals valuable and scarce metals saves saves moneymoney and has a and has a lower environmental impactlower environmental impact then mining and extracting them from their then mining and extracting them from their ores.ores.

Fig. 15-18, p. 351

Solutions

Sustainable Use of Nonrenewable Minerals

• Do not waste mineral resources.

• Recycle and reuse 60–80% of mineral resources.

• Include the harmful environmental costs of mining and processing minerals in the prices of items (full-cost pricing).

• Reduce subsidies for mining mineral resources.

• Increase subsidies for recycling, reuse, and finding less environmentally harmful substitutes.

• Redesign manufacturing processes to use less mineral resources and to produce less pollution and waste.

• Have the mineral-based wastes of one manufacturing process become the raw materials for other processes.

• Sell services instead of things. e.g. carpet rentals

• Slow population growth.

Mining & the US GovernmentMining & the US Government

The US Hardrock Mining Act was passed in The US Hardrock Mining Act was passed in 1872.1872.

How relevant do you think it is today?How relevant do you think it is today?

Case in point: In 2004, Case in point: In 2004, Phelps-DodgePhelps-Dodge bought public bought public land in Colorado worth land in Colorado worth $155,000,000 $155,000,000 for for $875.$875.

This is a good example of how governments This is a good example of how governments subsidizesubsidize mining and other resource extraction industries such mining and other resource extraction industries such as fishing fleets and logging companies.as fishing fleets and logging companies.

Case Study: Case Study: The Ecoindustrial RevolutionThe Ecoindustrial Revolution

Growing signs point to an Growing signs point to an ecoindustrial revolutionecoindustrial revolution taking place over the next 50 years.taking place over the next 50 years.

BiomimicryBiomimicry-The goal is to -The goal is to redesign industrial redesign industrial manufacturing processesmanufacturing processes to mimic how to mimic how naturenature deals deals with wastes .with wastes .

Industries can interact in Industries can interact in complex resource exchange complex resource exchange webswebs in which in which wastes from manufacturer become raw wastes from manufacturer become raw materials for anothermaterials for another..

The Ecoindustrial RevolutionThe Ecoindustrial Revolution 1975- 3M1975- 3M (makes 60,000 products in100 (makes 60,000 products in100

manufacturing plants) began “3P” programmanufacturing plants) began “3P” program Pollution Prevention PaysPollution Prevention Pays

• Redesigned equipment &processesRedesigned equipment &processes• Fewer hazardous raw materialsFewer hazardous raw materials• Identified hazardous wastes and recycled or sold them Identified hazardous wastes and recycled or sold them

as raw materials to other companiesas raw materials to other companies• Began making more nonpolluting productsBegan making more nonpolluting products• By 2005By 2005: sharply reduced waste production & air : sharply reduced waste production & air

pollution, and pollution, and saved almost $1 billion. saved almost $1 billion.

Since 1990, Since 1990, DuPont, BP, IBM, and a growing DuPont, BP, IBM, and a growing number of others have saved millions of number of others have saved millions of dollars with similar measures.dollars with similar measures.

Sludge

Pharmaceutical plant Local farmers

SludgeGreenhouses

Waste heat

Waste heat

Waste heat

Waste heat Fish farming

Oil refinery Surplus natural gas

Electric power plant Fly ash

Surplus sulfur

Surplus natural gas

Waste calcium sulfate

Waste heat

Cement manufacturer

Sulfuric acid producer

Wallboard factory Area homes

Industrial Ecosystem: Kalundborg, Denmark

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Geology and Nonrenewable Mineral Resources Chapter 14 Iron Ore