op ch15 lecture_earth3, mineral resources

Chapter 15: Riches in Rock: Mineral Resources Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak

Chapter 15Riches in Rock: Mineral Resources

©2008 W. W. Norton & Company, Inc.

Portrait of a PlanetThird Edition

earthearth

LECTURE OUTLINE

Riches in Rock: Mineral Resources

Riches in Rock: Mineral Resources

Prepared by

Ronald ParkerEarlham College Department of Geosciences

Richmond, Indiana

Prepared by

Ronald ParkerEarlham College Department of Geosciences

Richmond, Indiana


Mineral ResourcesMineral Resources Minerals from the crust that are used by civilization. Minerals from the crust that are used by civilization.

Minerals are present in almost everything we use.Minerals are present in almost everything we use. They are utterly necessary for modern industrial society. They are utterly necessary for modern industrial society.

Two major categories.Two major categories. Metallic.Metallic. Nonmetallic. Nonmetallic.


Mineral ResourcesMineral Resources Mineral resources form by geologic processes.Mineral resources form by geologic processes.

Occurrences are predictable.Occurrences are predictable. Formation is usually very slow.Formation is usually very slow.

Minerals are effectively nonrenewable resources.Minerals are effectively nonrenewable resources.


Mineral ResourcesMineral Resources


Mineral ResourcesMineral Resources Two major categories.Two major categories.

Metallic. Metallic. Gold.Gold.Silver.Silver.Copper.Copper.Lead.Lead.Zinc.Zinc. Iron.Iron.Aluminum.Aluminum.

Nonmetallic. Nonmetallic. Sand and gravel.Sand and gravel.Gypsum.Gypsum.Halite.Halite.Dimension stone.Dimension stone.


What Is a Metal?What Is a Metal? Opaque, shiny, smooth, conductive solids. Opaque, shiny, smooth, conductive solids. Metal properties from metallic chemical bonds.Metal properties from metallic chemical bonds.

Delocalized electrons move from atom to atom easily.Delocalized electrons move from atom to atom easily. Electron fluidity Electron fluidity createscreates electrical conductivity. electrical conductivity.


What Is a Metal?What Is a Metal? Properties due to crystal structure and bonding. Properties due to crystal structure and bonding.

Metals may be extremely hard (titanium) or soft (copper). Metals may be extremely hard (titanium) or soft (copper). Ductile – Able to be drawn into thin wires.Ductile – Able to be drawn into thin wires. Malleable – Able to be pounded into thin sheets. Malleable – Able to be pounded into thin sheets.


What Is a Metal?What Is a Metal? 3 categories.3 categories.

Native – Naturally occur in pure form. Native – Naturally occur in pure form. Copper (Cu)Copper (Cu)Silver (Ag)Silver (Ag)Gold (Au)Gold (Au)

Precious – Rare and economically important.Precious – Rare and economically important.Gold (Au)Gold (Au)Silver (Ag)Silver (Ag)Platinum (Pt)Platinum (Pt)

Base – Commonly used in industry.Base – Commonly used in industry. Iron (Fe)Iron (Fe)Lead (Pb)Lead (Pb)Zinc (Zn)Zinc (Zn)Tin (Sn)Tin (Sn)


The Discovery of MetalsThe Discovery of Metals Native metals occur naturally in a pure form.Native metals occur naturally in a pure form. Native metals are rare and durable. They include…Native metals are rare and durable. They include…

Gold.Gold. Silver.Silver. Copper.Copper. Iron.Iron.

We have utilized native metals for 1,000s of years.We have utilized native metals for 1,000s of years. Tools – They are easily shaped by cold working.Tools – They are easily shaped by cold working. Money – Chosen because of rarity and durability.Money – Chosen because of rarity and durability.


The Discovery of MetalsThe Discovery of Metals Quest for native metals important in human history.Quest for native metals important in human history.

Native American copper trade.Native American copper trade. Spanish Conquistadors. Spanish Conquistadors. California and Klondike gold.California and Klondike gold.

Today, minerals underpin the wealth of nations.Today, minerals underpin the wealth of nations.


MetalsMetals Native metals are too rare to be mine sources.Native metals are too rare to be mine sources. Instead, we use minerals that Instead, we use minerals that containcontain metals. metals.

Metal ions are bonded to non-metallic elements. Metal ions are bonded to non-metallic elements. Ore minerals rarely resemble the pure metal.Ore minerals rarely resemble the pure metal.


SmeltingSmelting Releases metals from the mineral. Releases metals from the mineral.

Different minerals require… Different minerals require… Different smelting techniques.Different smelting techniques.Different temperatures. Different temperatures.

Nonmetallic waste is called slag.Nonmetallic waste is called slag.


SmeltingSmelting Steel is made from iron smelted with carbon.Steel is made from iron smelted with carbon. Blending molten metals creates alloys.Blending molten metals creates alloys.

Alloy properties differ from pure metals.Alloy properties differ from pure metals. Bronze – An alloy of copper and tin.Bronze – An alloy of copper and tin. Brass – Copper alloyed with zinc.Brass – Copper alloyed with zinc.


What Is an Ore?What Is an Ore? Rock with a concentration of metal-rich minerals. Rock with a concentration of metal-rich minerals.

Present in enough abundance to be economic to mine.Present in enough abundance to be economic to mine. Metal must be readily extracted from the mineral.Metal must be readily extracted from the mineral. There are many different ore minerals.There are many different ore minerals.

Ores form via geological processes.Ores form via geological processes. Magmatic activity.Magmatic activity. Hydrothermal alteration.Hydrothermal alteration. Secondary enrichment.Secondary enrichment. Sedimentary processes.Sedimentary processes. Weathering processes.Weathering processes. Hydraulic sorting.Hydraulic sorting.


Common ore minerals.Common ore minerals.


Geologic processes often concentrate metals. Geologic processes often concentrate metals. Concentration must be high enough to yield a profit. Concentration must be high enough to yield a profit. The amount of useful metal present is the ore grade.The amount of useful metal present is the ore grade. The amount of enrichment required differs by metal. The amount of enrichment required differs by metal.

Ore FormationOre Formation


Ore FormationOre Formation Geologic processes generate mineral resources. Geologic processes generate mineral resources.

A dominant control is exerted by plate tectonics.A dominant control is exerted by plate tectonics. Tectonic effects are overprinted by the hydrologic cycle. Tectonic effects are overprinted by the hydrologic cycle.

Ore formation requires large amounts of time. Ore formation requires large amounts of time.


Ore FormationOre Formation Mineral resource occurrence is predictable.Mineral resource occurrence is predictable. Ores are not equitably distributed.Ores are not equitably distributed.

Some countries have many mineral resources.Some countries have many mineral resources. Other countries lack resources. Other countries lack resources.


Ore FormationOre Formation Magmatic ores.Magmatic ores.

Sulfide minerals crystallize early and sink in magma.Sulfide minerals crystallize early and sink in magma. Form massive sulfide ores at the bottom of chamber.Form massive sulfide ores at the bottom of chamber. Sulfides include…Sulfides include…

Pyrite.Pyrite.Chalcopyrite.Chalcopyrite.Bornite.Bornite.Galena.Galena.


Ore FormationOre Formation Hydrothermal deposits. Hydrothermal deposits.

Minerals deposited by hot, chemically active fluids.Minerals deposited by hot, chemically active fluids. Common in rocks heated by plutonic intrusions. Common in rocks heated by plutonic intrusions. Often crystallize in rock fractures as vein deposits. Often crystallize in rock fractures as vein deposits.



Black smokers - Occur along all mid-ocean ridges.Black smokers - Occur along all mid-ocean ridges.Seawater in cracked hot crust is heated, picking up metals.Seawater in cracked hot crust is heated, picking up metals.Water cycles back to the cold ocean, metals crystallize out.Water cycles back to the cold ocean, metals crystallize out.



Mississippi Valley-type (MVT) ores.Mississippi Valley-type (MVT) ores.Orogenic belts “squeegee” hot water through deep basins. Orogenic belts “squeegee” hot water through deep basins. The hot water leaches minerals and carries them along.The hot water leaches minerals and carries them along.Where basin brines surface and cool, they deposit metals. Where basin brines surface and cool, they deposit metals. MVT lead-zinc (Pb-Zn) deposits.MVT lead-zinc (Pb-Zn) deposits.


Ore FormationOre Formation Secondary-enrichment deposits. Secondary-enrichment deposits.

Ground water leaches and oxidizes primary sulfide ores.Ground water leaches and oxidizes primary sulfide ores. Adding OAdding O22, OH, and CO, OH, and CO22, some secondary ores are prized., some secondary ores are prized.

Malachite.Malachite.Azurite.Azurite.Turquoise.Turquoise.


Ore FormationOre Formation Sedimentary deposits.Sedimentary deposits.

Banded iron formations (BIFs).Banded iron formations (BIFs).Layered specular hematite (FeLayered specular hematite (Fe22OO33) and red chert (jasper).) and red chert (jasper).

Found globally 2.5 – 2 Ga with OFound globally 2.5 – 2 Ga with O22 buildup in atmosphere. buildup in atmosphere.

Manganese (MnOManganese (MnO2 2 )–rich nodules.)–rich nodules.Rich in trace elements, these grow slowly on the seafloorRich in trace elements, these grow slowly on the seafloor


Ore FormationOre Formation Residual mineral deposits. Residual mineral deposits.

Form via extreme (tropical) chemical weathering.Form via extreme (tropical) chemical weathering. Intense weathering strips almost everything out of soil.Intense weathering strips almost everything out of soil. Residual lateritic soil is enriched in Fe and Al oxides. Residual lateritic soil is enriched in Fe and Al oxides.

Bauxite – Primary ore of aluminum.Bauxite – Primary ore of aluminum.


Ore FormationOre Formation Placer deposits – Concentrated by flowing water. Placer deposits – Concentrated by flowing water.

In high-velocity water… In high-velocity water… Low-density minerals are suspended and washed away.Low-density minerals are suspended and washed away.High-density grains are concentrated by settling out.High-density grains are concentrated by settling out.

Important for gold, tin, and iron.Important for gold, tin, and iron. Best preserved in fossil Best preserved in fossil

stream sediments. stream sediments.


Mineral ExplorationMineral Exploration Ores are located by evidence of metal enrichment. Ores are located by evidence of metal enrichment.

Color – Enrichment often discolors rock and soil.Color – Enrichment often discolors rock and soil. Geophysical surveys – Magnetism, gravity, radioactivity. Geophysical surveys – Magnetism, gravity, radioactivity. Geochemical surveys – Ore can be found by chemical Geochemical surveys – Ore can be found by chemical

analyses of water, stream sediment, soil, and biota.analyses of water, stream sediment, soil, and biota.


Mineral ExplorationMineral Exploration Ore present in a deposit is assessed by...Ore present in a deposit is assessed by...

Geophysical measurements. Geophysical measurements. Core drilling.Core drilling. Geochemical analyses. Geochemical analyses.

If economic, a deposit is If economic, a deposit is

developed for mining.developed for mining.


Mineral ProductionMineral Production Open-pit mines – Large excavations open to the air.Open-pit mines – Large excavations open to the air. Less expensive and dangerous than tunnel mines.Less expensive and dangerous than tunnel mines. Usually require ore within Usually require ore within

100 m of the land surface. 100 m of the land surface.


Mineral ProductionMineral Production Underground mines – Ore obtained by tunneling. Underground mines – Ore obtained by tunneling.

Tunnels are linked to a vertical shaft (an adit).Tunnels are linked to a vertical shaft (an adit). Ore is removed by drilling and blasting.Ore is removed by drilling and blasting. Excavated ore is hauled to the surface for processing.Excavated ore is hauled to the surface for processing. Expensive and dangerous. Expensive and dangerous.


Nonmetallic ResourcesNonmetallic Resources Materials that lack metals are used by humans. Materials that lack metals are used by humans.

Dimension stone – Rock slabs used as building material. Dimension stone – Rock slabs used as building material. Crushed stone – Material for roads, asphalt, and concrete.Crushed stone – Material for roads, asphalt, and concrete. Cement – Mixture of heated limestone, quartz, and clay. Cement – Mixture of heated limestone, quartz, and clay.


Nonmetallic ResourcesNonmetallic Resources Nonmetallic minerals commonly used in homes. Nonmetallic minerals commonly used in homes.

Calcite – Base material of cement (concrete). Calcite – Base material of cement (concrete). Clay minerals – Used for bricks, pottery, dishware. Clay minerals – Used for bricks, pottery, dishware. Gypsum – Most common material in wallboard or plaster.Gypsum – Most common material in wallboard or plaster. Quartz – Used to make window glass. Quartz – Used to make window glass.

U.S. per capita nonmetallic mineral use is huge. U.S. per capita nonmetallic mineral use is huge.


Global Mineral NeedsGlobal Mineral Needs Mineral resources are nonrenewable.Mineral resources are nonrenewable.

They form as the result of geologic processes.They form as the result of geologic processes. These processes are too slow to generate new deposits.These processes are too slow to generate new deposits.


Global Mineral NeedsGlobal Mineral Needs Mineral resources are not evenly distributed. Mineral resources are not evenly distributed.

Some countries are mineral-rich; some are mineral-poor.Some countries are mineral-rich; some are mineral-poor. This is a particular issue for strategic mineral resources. This is a particular issue for strategic mineral resources.

Metals needed for highly specialized applications.Metals needed for highly specialized applications. National security and defense.National security and defense. Aerospace.Aerospace.


Global Mineral NeedsGlobal Mineral Needs How long will current mineral resources last?How long will current mineral resources last?

Depends upon consumption rates and reserve amounts.Depends upon consumption rates and reserve amounts.

Some mineral resources will run out soon.Some mineral resources will run out soon. Global resources of Pb, Zn, and Au? Global resources of Pb, Zn, and Au? < 30 years.< 30 years. U.S. resources of Pt, Ni, Co, Mn, Cr? U.S. resources of Pt, Ni, Co, Mn, Cr? <1 year.<1 year.


Global Mineral NeedsGlobal Mineral Needs Continued use of scarce minerals will require…Continued use of scarce minerals will require…

Discovery of new sources. Discovery of new sources. Increase in price to make hard-to-get reserves profitable. Increase in price to make hard-to-get reserves profitable. Increased efficiency and conservation. Increased efficiency and conservation. Substitution.Substitution. Recycling. Recycling. Doing without.Doing without.


Environmental IssuesEnvironmental Issues Extraction and processing has large impacts.Extraction and processing has large impacts.

Air.Air. Surface water.Surface water. Ground water.Ground water. Soils.Soils. Biota.Biota. Aesthetics.Aesthetics.


Environmental IssuesEnvironmental Issues Acid mine drainage (AMD).Acid mine drainage (AMD).

Sulfides exposed to OSulfides exposed to O22 create sulfuric acid. create sulfuric acid. Water from spoil piles is acidified (pH < 5.7).Water from spoil piles is acidified (pH < 5.7). AMD creates toxic conditions.AMD creates toxic conditions.

Mobilizes heavy metals. Mobilizes heavy metals. Kills stream organisms. Kills stream organisms.


Environmental IssuesEnvironmental Issues Spoil – Material removed to expose ore.Spoil – Material removed to expose ore. Tailings – Mineral processing wastes.Tailings – Mineral processing wastes. Both have large adverse environmental impacts.Both have large adverse environmental impacts.

Acid leachates contaminate ground and surface water. Acid leachates contaminate ground and surface water. Aesthetic disruption.Aesthetic disruption. Respirable dusts.Respirable dusts.


Chapter 15Riches in Rock: Mineral Resources

©2008 W. W. Norton & Company, Inc.

Portrait of a PlanetThird Edition

earthearth

LECTURE OUTLINE

This concludes the

op ch15 lecture_earth3, mineral resources

Education