Chapter 16Chapter 16

Nonrenewable Mineral Nonrenewable Mineral Resources – Part 2Resources – Part 2

Key QuestionsKey Questions What are nonrenewable mineral resources What are nonrenewable mineral resources

and how are they formed?and how are they formed?

How do we find and extract nonrenewable How do we find and extract nonrenewable mineral and energy resources from the mineral and energy resources from the earth’s crust?earth’s crust?

How fast are mineral supplies being used How fast are mineral supplies being used up?up?

What are Mineral Resources?What are Mineral Resources?

Concentration of naturally occurring Concentration of naturally occurring material in or on the earth’s crust material in or on the earth’s crust that can be extracted and processed that can be extracted and processed into useful materialsinto useful materials

Classified as Classified as nonrenewable resourcesnonrenewable resources because they take so long to producebecause they take so long to produce

We know how to find and extract We know how to find and extract 100+ nonrenewable minerals from 100+ nonrenewable minerals from the earth’s crustthe earth’s crust

We can extract…We can extract…

Metallic mineral resourcesMetallic mineral resources (iron, (iron, copper, aluminum)copper, aluminum)

Nonmetallic mineral resourcesNonmetallic mineral resources (salt, (salt, clay, sand, phosphates, soil)clay, sand, phosphates, soil)

Energy resourcesEnergy resources (coal, oil, natural (coal, oil, natural gas, uranium)gas, uranium)

OreOre

Rock containing enough of 1+ Rock containing enough of 1+ metallic minerals to be mined for metallic minerals to be mined for profitprofit

We convert 40 metals extracted from We convert 40 metals extracted from ores into everyday items that are ores into everyday items that are either 1) used and thrown away OR either 1) used and thrown away OR 2) reused or recycled2) reused or recycled

Categories of nonrenewable Categories of nonrenewable mineral resourcesmineral resources

US Geological Survey divides nonrenewable US Geological Survey divides nonrenewable mineral resource into categories:mineral resource into categories:

1.1. Identified resourcesIdentified resources: deposits of nonrenewable : deposits of nonrenewable mineral resource with a known location and mineral resource with a known location and quantityquantity

2.2. Undiscovered resourcesUndiscovered resources: potential supplies : potential supplies assumed to exist in theoryassumed to exist in theory

3.3. ReservesReserves: identified resources from which : identified resources from which resource can be extracted for profitresource can be extracted for profit

4.4. Other resourcesOther resources: identified and discovered but : identified and discovered but not classified as reserves not classified as reserves

How do ores form from magma?How do ores form from magma?

Ores form as a result of internal and Ores form as a result of internal and external geologic processesexternal geologic processes

Plate tectonics shape the earth’s Plate tectonics shape the earth’s crust and determine where the crust and determine where the richest mineral deposits are foundrichest mineral deposits are found

As magma cools, it crystallizes into mineral-containing igneous rocks

Ore deposits form through hydrothermal processes

Upwelling magma solidifies into black smokers

Shoots out mineral-rich hot water on the seafloor

Minerals accumulate as hot and cold water contact

Form ore deposits rich in copper, lead, zinc, silver, and gold

Finding nonrenewable resourcesFinding nonrenewable resources

Aerial photos and satellite imagesAerial photos and satellite images Planes that detect deposits of radioactive Planes that detect deposits of radioactive

metalsmetals Gravimeter to measure differences in Gravimeter to measure differences in

density (ore differs from surrounding rock)density (ore differs from surrounding rock) Drilling deep well and extracting core Drilling deep well and extracting core

samplessamples Seismic surveys by explosions and Seismic surveys by explosions and

analyzing shock wavesanalyzing shock waves Chemical analysis of water and plants Chemical analysis of water and plants

(absorb minerals)(absorb minerals)

Mining techniques (once resources Mining techniques (once resources have been found)have been found)

Surface miningSurface mining: equipment strips outer layer of : equipment strips outer layer of soil and rock; in US, used to extract 90% nonfuel soil and rock; in US, used to extract 90% nonfuel resources and 60% coalresources and 60% coal

Open-pit miningOpen-pit mining: machines dig holes and remove : machines dig holes and remove oresores

DredgingDredging: chains scrape underwater mineral : chains scrape underwater mineral depositsdeposits

Area strip miningArea strip mining: parallel strips made in flat land; : parallel strips made in flat land; power shovels usedpower shovels used

Contour strip miningContour strip mining: terraces cut into side of hill; : terraces cut into side of hill; power shovels usedpower shovels used

Mountaintop removalMountaintop removal: explosives used to remove : explosives used to remove top of mountain and expose coal underneathtop of mountain and expose coal underneath

Open Pit Mine

Dredging

Area Strip Mining

Contour Strip Mining

Surface Mining Control and Surface Mining Control and Reclamation Act of 1977Reclamation Act of 1977

Requires mining companies to Requires mining companies to restore surface-mined land so that it restore surface-mined land so that it is usable againis usable again

Although surface-mined land can be Although surface-mined land can be restored, it is expensive and not restored, it is expensive and not done in many countriesdone in many countries

Subsurface miningSubsurface mining

Used to remove coal and other metal Used to remove coal and other metal ores that are too deep to be ores that are too deep to be extracted by surface miningextracted by surface mining

Blast tunnels to get to deposit, use Blast tunnels to get to deposit, use machinery to transport ore to the machinery to transport ore to the surfacesurface

Disturbs 1/10 as much land as Disturbs 1/10 as much land as surface mining, produces less wastesurface mining, produces less waste

More dangerous and expensive More dangerous and expensive

Environmental Effects of Extracting Environmental Effects of Extracting Mineral ResourcesMineral Resources

Fig. 15-6 p. 343

Percolation to groundwaterLeaching of toxic metalsand other compoundsfrom mine spoil

Acid drainage fromreaction of mineralor ore with water

Spoil banks

Runoff ofsediment

Surface MineSubsurfaceMine Opening

Leaching may carryacids into soil andgroundwater supplies

Acid mine drainage-pollution and degradationby acid runoff and toxic chemicals from mining-can kill fish and other aquatic life

Surface mining

Metal ore

Separationof ore frommachine

Scattered in environment

Recycling

Discarding of product

Conversion to product

Melting metal

Smelting

Processes involved in extractionProcesses involved in extraction

SmeltingSmelting: used to separate metal : used to separate metal from other elements in the orefrom other elements in the ore

Enormous amount of pollution which Enormous amount of pollution which damages surrounding vegetation and damages surrounding vegetation and soilsoil

Smelters also produce liquid and Smelters also produce liquid and hazardous waste that must be hazardous waste that must be disposed of safely disposed of safely

Are there environmental limits?Are there environmental limits? Resource experts believe that the Resource experts believe that the

greatest danger from increasing greatest danger from increasing consumption of nonrenewable consumption of nonrenewable resources is environmental damage resources is environmental damage caused by extraction and processing.caused by extraction and processing.

More accessible and high-grade ores More accessible and high-grade ores are exploited firstare exploited first

It takes more $ to exploit the deeper It takes more $ to exploit the deeper ores, causing more environmental ores, causing more environmental effectseffects

Will there be enough mineral Will there be enough mineral resources?resources?

Future of nonrenewable minerals depends on: actual supply and rate at which supply is used

Economic depletion: cost more to find, extract, transport and process than it’s worth

Depletion time: time it takes to use up a certain proportion of NM

Supplies of mineral resources

Reserve-to-production ratio: number of years that reserves of a NM will last

Materials revolution: new materials (ceramics and plastics) are being developed as replacements for metals

Substitutes cannot be found for many mineral resources