Earthquakes Occur when a part of the earth’s crust suddenly fractures and shifts to relieve stress. Energy is released in the form of shock waves

The Richter scale Measures the intensity of the shockwaves Each unit (for example 4 to 5) has 10 times more amplitude A magnitude 6 earthquake has 100 times more magnitude than a magnitude 4 quake.

Scale <4 insignificant minor 5.0 – 5.9 damaging destructive major >8.0 great

Primary effects Shaking of ground Permanent vertical or horizontal displacement of the ground Buildings, pipelines, roads, bridges derange

Secondary effects Rock slides Land slides Urban fires Flooding caused by subsidence of land Coastal flooding Tsunamis

Earthquake readiness Enforce building code for property in high risk areas Limit height of buildings Re-inforcing structures Monitoring activity

Expected damage from earthquakes in the US and Canada

Volcanic Activity Some volcanoes erupt quietly and release flows of molten rock but others erupt explosively and spew large chunks of rock, ash and harmful gases into the atmosphere

Disadvantages: Advantages:

summizing AdvantagesDisadvantages New rock, new mineralsSO 2 gas emitted forms H 2 SO 4 (sulfuric acid) Land formingCO 2 gas emitted forms H 2 CO 3 (carbonic acid) Renews mineral resourcesAcid droplets reflect sunlight resulting in cooling effect of the atmosphere

Types of rock Igneous Basalt Granite metamorphic Produced by pressure and temperature exerted on existing rock sedimentary Formed from sediment by weathering and erosion and subsequent cementation

Non-renewable Mineral Resources Mineral resources are non-renewable materials that we can extract from the earth’s crust.

We extract over 100 nonrenewable minerals from earth’s crust Iron Copper Aluminum Salt Clay Sand Phosphates Soild Coal Oil Natural gas uranium

Natural Capital Identified: known location, quantity and quality Reserves: identified resource from which a usable Nonrenewable mineral can be extracted profitably Undiscovered: potential supplies based on geologic Knowledge Other resources: undiscovered identified resources Not classified as reserves

How are mineral deposits found? Aerial photography Studying rock outcrops Radiation measurements Magnetometer Gravimeter Drilling Sample extraction Seismic surveys (detonations) Chemical analysis

How are buried mineral deposits removed?

Surface mining Uses mechanized equipment to strip away overburden of soil and rock which are discarded as spoils. Process depends on resource being mined and local topography Leaves great environmental damage USA Surface Mining Control and Reclamation Act of 1977 requires mining companies to restore land; However, strong lobbying of elected officials have weakened the law

Types of surface mining Open pit (iron, copper, sand, gravel stone) Dredging (underwater deposits) Area strip mining (dig trenches and fill them with overburden; leaves wavy series of highly erodible rubble called spoil banks) Contour strip mining (used in hilly areas, cuts series of terraces into side of hill; overburden of new terrace is dumped on terrace below) Mountaintop removal (using explosives; very damaging to environment; practiced in West Virginia.

Subsurface mining Removes coal and ores deep under the surface Uses vertical and horizontal shafts Disturbs less than 1/10 th of the land as surface mining and produces less waste materials. More dangerous More expensive Health hazards

Environmental Effects Extracting, processing and using mineral resources disturbs the land, harms workers, erodes the soil, produces large amounts of solid waste and pollutes the air, water and soil

Environmental Cost of Mining Scarring and disruption of the land surface Susidence (land above mine shafts collapses) Toxin – laced mingin wastes Acid mine drainage Toxic emissions from ore processing

Metal ore  metal + gangue (waste) Removing gangue produces tailings Tailings are toxic and can be carried by wind or leach and Contaminate ground waters

Mining has polluted about 40% of western watersheds

StepsEnvironmental Effects exploration, extraction Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing transportation, purification, manufacturing Use transportation or transmission to individual user, eventual use, and discarding Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Figure Page 343

Smelting separates pure metal out

Lots and lots of air pollution

Greatest cost of mining to environment.. is not the mining process (or exhausting mineral resources) BUT The extraction, processing and conversion to products

To make these

To make a fistful of gold Produces the amount of 50 of these

Cyanide heap leaching Is a cheap way to extract gold from very low grade ore. Cyanide is toxic and is use to extract 85% of gold from ore.

Who pays for all the damage? The companies? NO The consumers, by paying a higher price? NO HA HA IT’S YOU! THE FUTURE GENERATION. Time to wake up

Depletion curve for nonrenewable Resource using three sets of assumptions. Dashed Vertical lines represent times when 80% depletion Occurs.

What does the future hold? 1.Should government subsidize mining ? 2.Should more public land be made available for mining companies 3.Are there technologies out there that can save us? 4. What are metals used for and are there alternatives for them?

how long will we have… MetalTime Aluminum 2139 Copper 2039 coal 2158 Gold m