Terrestrial EarthTerrestrial Earth

Plate Tectonics, Minerals, Rocks & Plate Tectonics, Minerals, Rocks & MiningMining

Plate tectonics shapes the Plate tectonics shapes the EarthEarth

Plate tectonicsPlate tectonics = process that underlies earthquakes and = process that underlies earthquakes and volcanoes and that determines the geography of the Earth’s volcanoes and that determines the geography of the Earth’s surfacesurface

CrustCrust = lightweight thin component of Earth’s surface = lightweight thin component of Earth’s surface MantleMantle = malleable layer on which the crust floats = malleable layer on which the crust floats CoreCore = molten heavy center of Earth made mostly of iron = molten heavy center of Earth made mostly of iron

Pangaea: the supercontinent

PangaeaPangaea = at least = at least twice in Earth’s twice in Earth’s history, all history, all landmasses were landmasses were joined in one joined in one supercontinentsupercontinent

Earth’s crust is Earth’s crust is constantly created and constantly created and

destroyeddestroyed Divergent plate boundariesDivergent plate boundaries = = magma surging upward to the magma surging upward to the surface divides plates and surface divides plates and pushes them apart, creating new pushes them apart, creating new crust as it cools and spreads crust as it cools and spreads

Transform plate boundaryTransform plate boundary = = two plates meet, slipping and two plates meet, slipping and grinding alongside one anothergrinding alongside one another– Friction spawns earthquakes Friction spawns earthquakes

along slip-strike faultsalong slip-strike faults

Tectonic plates can Tectonic plates can collidecollide Convergent plate boundariesConvergent plate boundaries

= where plates collide= where plates collide SubductionSubduction = one plate of = one plate of

crust may slide beneath anothercrust may slide beneath another

– Magma erupts through the Magma erupts through the surface in volcanoessurface in volcanoes

Two colliding plates of Two colliding plates of continental crust may lift continental crust may lift material from both platesmaterial from both plates

– Resulted in the Himalaya Resulted in the Himalaya and Appalachian mountainsand Appalachian mountains Boundary Interactive

Boundary Animations

The Earth has 15 major The Earth has 15 major tectonic platestectonic platesMovement of these plates influences climate and evolution

Minerals and RocksMinerals and Rocks What is a mineral?What is a mineral?

– naturally occurring, inorganic, solid element or compound naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal with a definite chemical composition and a regular internal crystal structurecrystal structure

What is rock?What is rock?– solid, cohesive, aggregate of one or more mineralssolid, cohesive, aggregate of one or more minerals– Each rock type has a characteristic mixture of mineralsEach rock type has a characteristic mixture of minerals

What is an Ore?What is an Ore?– Rock with large concentration of a particular maineral to Rock with large concentration of a particular maineral to

make it profitablemake it profitable– High and low grade oresHigh and low grade ores

» NON- Metalic MineralNON- Metalic Mineral Sand, gravel, limestoneSand, gravel, limestone

» MetalicMetalic Aluminum, Steel, manganese, cobalt, chromium, Copper, GoldAluminum, Steel, manganese, cobalt, chromium, Copper, Gold

MineralsMinerals

Fig. 16-9 p. 339Fig. 16-9 p. 339

Igneous RockGranite, Pumice,

Basalt

Sedimentary RockShale, Sandstone,

Limestone

Metamorphic RockSlate, Quartzite,

Marble

Magma(Molten Rock)

WeatheringWeathering

ErosionErosion

TransportTransportDepositionDeposition

Heat,Pressure

Heat,Pressure

Heat,

Pressure

Heat,

Pressure

Rock Cycle

Types of Mining: • Surface Mining: Scoop ore off surface or earth.

• cheap. • safe for miners. • large environmental destruction.

• Sub-Surface or Underground Mining: Use of shafts to reach deeply buried ores.

• expensive. • hazardous for miners. • less environmental damage.

Mining: Extract Ore from GroundMining: Extract Ore from Ground

Surface MiningSurface Mining open pit mining:

• circular hole in ground, with ramp circling down along sides, allows deeper ore to be reached.

Surface Mining- Strip MiningSurface Mining- Strip Mining

strip-mining: scoop off rock overburden, and then scoop off ore material.

• Economics of strip mining depend on stripping ratio

• Large land area can be involved, especially for coal and bauxite.

Results of Mining utube

In the Earth's Crust, in every million atoms, around 82 000 of them are Aluminum, (82 000 ppm1), by weight. This is around 8 % or almost one

in every 12 atoms. This places aluminum amongst the world's most abundant elements.

Despite being present of Earth in such incredibly vast quantities on Earth, the metal never occurs on it's own in nature. Instead of existing

free like Gold and Silver, due to its higher level of reactivity, it is always chemically bonded in compounds when it normally occurs. The most

common of these compounds is Bauxite, or Aluminum Ore which contains large quantities of Aluminum Oxide.

Bauxite Mine

Mountain Top RemovalMountain Top Removal

Removing Overburden

OverburdenCoal seembedrock

spoils

Appalachian Voiceshttp://www.youtube.com/watch?v=aiSzOiGFa-0

Gold in QuartzGold in Quartz

A large quartz boulder with a lot of visible gold. A large quartz boulder with a lot of visible gold. Usually, the gold is much finer and hard to see.Usually, the gold is much finer and hard to see.

https://www.youtube.com/watch?v=ohrrE1rjzLo

Placer DepositionPlacer Deposition

Panning for Panning for gold in a gold in a placer placer depositdeposit

Aeolian PlacersAeolian Placers

The "diamond crawl" in a The "diamond crawl" in a deflation basin, Diamond deflation basin, Diamond Area No 1, NamibiaArea No 1, Namibia

Diamond concentrations Diamond concentrations were increased by wind were increased by wind erosionerosion

Environmental Impact of MiningMining

Waste water/sludge damsWaste water/sludge dams

Underground MiningUnderground Mining• A technology originating in antiquity.

• A variety of configurations, depending upon conditions

Acid Mine DrainageAcid Mine Drainage

Scaring the land surface- result Scaring the land surface- result spoils banksspoils banks Soil poor, windblown .. Primary succession slowSoil poor, windblown .. Primary succession slow

Toxic wastewater stored in sludge dams.Toxic wastewater stored in sludge dams.– Toxins include slenium, arsenic, and mercuryToxins include slenium, arsenic, and mercury

Environmental Impact of MiningMining

CassiteriteCassiterite tin oxide ore mineral, SnO2. It is generally tin oxide ore mineral, SnO2. It is generally

opaque but is translucent in thin crystals. Its opaque but is translucent in thin crystals. Its luster and multiple crystal faces produce a luster and multiple crystal faces produce a desirable gem. Cassiterite has been the chief desirable gem. Cassiterite has been the chief tin ore throughout ancient history and tin ore throughout ancient history and remains the most important source of tin remains the most important source of tin today today

TinSoldiers

Non-Non-renewable renewable Mineral Mineral

Resource Resource Depletion Depletion

CurvesCurves

Source: Miller, G. Tyler, Living In The Environment. (2000) Wadsworth Publishing. New York.

Non-Non-renewable renewable Mineral Mineral

Resource Resource Depletion Depletion

CurvesCurves

Source: Miller, G. Tyler, Living In The Environment. (2000) Wadsworth

Publishing. New York.

US Non-renewable Resource US Non-renewable Resource ReservesReserves

Source: Miller, G. Tyler, Living In The Environment. (2000) Wadsworth Publishing. New York.

The decision to mine (or not to mine) a particular ore deposit depends upon:

1. an analysis of costs, benefits and risks

2. tangible (i.e. dollar profit)

3. intangible (i.e. hopes of stimulating the economy, fears of environmental damage)

Mining is an Economic ActivityMining is an Economic Activity

Gradual shift toward surface mining

Surface mining

Minining Lawhttp://www.youtube.com/watch?v=ofN1aLMwcUI

Mining around the worldHungary’s disaster

China’s rare earth mineralsUS rare earth mineral info ad

Proposal for New Massive Mine in Romania

GoldminingMining ore

Bauxite miningMountaintop removal

Mining Mining IssuesIssues

Mine Safety:

In U.S., stringent mining regulations

have lead to a reduction in

fatalities, both in terms of total deaths per year, deaths per

person-hour worked, and deaths

per ton mined.

surface

Acid Mine DrainageAcid Mine Drainage

• collapse of mine. • fire (methane, coal dust, etc.).

• asphyxiation (methane, carbon monoxide, etc.). • pneumoconiosis (from inhaling coal dust). • asbestosis (from inhaling asbestos fibers).

• silicosis (from inhaling silicate dust). • heavy metal poisoning (e.g. mercury).

• radiation exposure (in uranium mining).

Health ProblemsHealth Problems

Environmental DamageEnvironmental Damage• Gaping holes in ground (old open pit mines).

• Piles of mine tailings (non-ore removed from mines). • Accidental draining of rivers and lakes.

• Disruption of ground water flow patterns. • Loss of topsoil in strip-mined regions (350 to 2,700 km2 in

US alone). • Contamination from sulfuric acid (H2SO4) produced

through weathering of iron sulfide (FeS2, pyrite) in tailings.

4FeS2 + 14H2O = 4Fe(OH)3 + 8H2SO4

• Contamination from heavy metals (e.g. arsenic, mercury) in mine tailings.

1. Production of huge piles of slag. 2. Emission of CO2, a greenhouse gas, into the

atmosphere.3. Pollution associated with the generation of electricity

needed in anode furnaces (especially aluminum).4. Sulfur dioxide emissions from the refining of sulfide

ores are a major source of air pollution. The sulfur dioxide combines with water to produce sulfuric acid.

5. Release of heavy metals (As, Cd, Hg), present in trace quantities in sulfide ores, into the atmosphere.

Smelting and Refining: Smelting and Refining: Environmental ProblemsEnvironmental Problems

• Amount of commodities mined per year has generally increased.

• Commodity prices can take big swings, but average prices during the last century often declined or remained constant.

Cost TrendsCost Trends

Ore grades have all decreased as

milling technology has improved

copper

Cents per pound