Core Case Study: Environmental Effects of Gold Mining What countries mine the most gold? South Africa Australia United States Canada What is cyanide heap leaching? To extract gold, miners spray a solution of highly toxic cyanide salts (which react with gold) onto huge open-air piles of crushed rock.

Gold Mine with Cyanide Leach Piles and Ponds in South Dakota

Ryan would take all his notes Complete Cornell Notes for all 5 objectives and the answers the 3 summary questions

Geology and Nonrenewable Minerals Chapter 14

What Are the Earth’s Major Geological Processes and Hazards? Objective 1 What Are the Earth’s Major Geological Processes and Hazards? 14-2 of Packet

The Earth Is a Dynamic Planet What is geology? The science devoted to the student of dynamic processes occurring on the earth’s surface and interior Three major concentric zones of the earth Core – inner most zone Mantle – surrounding the core Including the asthenosphere Crust – outermost and thinnest layer Continental crust – underlies the continents Oceanic crust: 71% of crust

The Earth Beneath Your Feet Is Moving We tend to think of earth’s crust, mantle, and core as fairly static. In reality, convection cells, or currents move large volumes of rock and heat in loops within the mantle like a gigantic conveyer belt. Tectonic Plates move extremely slow atop the denser mantle on soft rock in the underlying asthenosphere Lithosphere are thick plates composed of the continental and oceanic crust and the rigid, outermost part of the mantle.

The Earth’s Major Tectonic Plates

Three types of boundaries between plates 1) Divergent plates - move apart Magma – molten rock flows up through the resulting cracks. Oceanic ridge – is created when plate diverge 2) Convergent plates – oceanic plates collides with a continental plate Subduction – continental plate rides up over the denser oceanic plate and pushes it down into the mantle Subduction zone – the area where the collision and subduction take place Trench – forms at the boundary between the two converging plates 3) Transform fault – plates slide and glide past one another along a fracture (fault) in the lithosphere example: San Andreas fault

The Earth’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates 14-3 of Packet

The San Andreas Fault as It Crosses Part of the Carrizo Plain in California, U.S.

Some Parts of the Earth’s Surface Build Up and Some Wear Down Internal geologic processes Generated by heat from the earth’s interior, generally build up the earth’s surface in the form of continental and oceanic crust External geologic processes Weathering Physical, Chemical, and Biological Driven by the energy from the sun and influenced by gravity, tend to wear down the earth’s surface Erosion – dissolved, loosened, or worn away Wind Flowing water Human activities Glaciers – under the influence of gravity, glaciers move slowly down a mountain side or over a wide area

Biological, Chemical, & Physical Processes Copy Figure 14-6 in your notes

Volcanoes Release Molten Rock from the Earth’s Interior Volcano – occurs where magma reaches the earth’s surface through a central vent or a long crack (a.k.a. fissure) Magma – molten rock Lava – magma that reaches the earth’s surface 1980: Eruption of Mount St. Helens The worst volcanic disaster in US history 1991: Eruption of Mount Pinatubo The largest volcanic eruption during the 20th century Benefits of volcanic activity – highly fertile soil

Creation of a Volcano

Pompeii

Earthquakes Are Geological Rock-and-Roll Events Seismic waves – vibrations Focus – the place where the earth quake begins Epicenter – the earth’s surface directly above the focus Magnitude – the severity of an earthquake Amplitude – size of the seismic waves Richter scale Insignificant: <4.0 Minor: 4.0–4.9 Damaging: 5.0–5.9 Destructive: 6.0–6.9 Major: 7.0–7.9 Great: >8.0

Major Features and Effects of an Earthquake

Areas of Greatest Earthquake Risk in the United States

Areas of Greatest Earthquake Risk in the World

Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis Tsunami a.k.a tidal wave – a series of large waves generated when part of the ocean floor suddenly rises or drops December 2004: Indian Ocean tsunami Magnitude of 9.15 Waves as high as 31 meters (100 feet)

Formation of a Tsunami and Map of Affected Area of Dec 2004 Tsunami

Shore near Gleebruk in Indonesia before and after the Tsunami on June 23, 2004

How Are the Earth’s Rocks Recycled? Objective 2 Copy Figure 14-13 in your notes

There Are Three Major Types of Rocks Earth’s crust is Composed of Minerals – an element or inorganic compound that occurs naturally in the earth’s crust Rocks – a solid combination of one or more minerals found in the earth’s crust (we will talk more about minerals next objective) Examples of mineral resources are fossil fuels (coal, oil, and natural gas) metallic minerals (such as aluminum, iron, and copper) nonmetallic minerals (such as sand, gravel, & limestone) As they take so long to produce, these components of the earth’s natural capital are classified as nonrenewable mineral resources.

The Earth’s Rocks Are Recycled Very Slowly Rock cycle – the interaction of physical and chemical processes that change rocks from one type to another Slowest of the earth’s cyclic processes

Three broad classes of rocks, based on formation Igneous rock is formed below or on the earth’s surface when molten rock wells up and hardens. They form the bulk of the earth’s crust. Sedimentary rock is formed from small, eroded pieces of rock that are carried to downhill sites. Layers accumulate over time and an increase of weight and pressure plus dissolved minerals bind the sediment particles together to form sedimentary rock. Metamorphic rock is produced from preexisting rock that is subjected to high temperatures, high pressures, chemically active fluids, or some combination of these.

Three broad classes of rocks, based on formation Sedimentary – made of sediments Examples of sedimentary rock Sandstone Shale Dolomite Limestone Lignite Bituminous coal Igneous – forms below or on the earth’s surface when magma cools and hardens Examples of igneous rock Granite Lava rock Metamorphic – pressure and heat Examples of metamorphic rock Anthracite Slate Marble

What Are Mineral Resources, and what are their Environmental Effects? Objective 3 What Are Mineral Resources, and what are their Environmental Effects?

We Use a Variety of Nonrenewable Mineral Resources Fossil fuels – like coal Metallic minerals – like aluminum, iron, & copper Nonmetallic minerals – like sand, gravel, & lime stone Ore After waste material is removed from metal ores they are smelted or treated with chemicals to extract the desired metal. High-grade ore – contains large amounts of the desired nonrenewable mineral Low-grade ore – contains a smaller amount of the mineral

Mineral resources can be classified into four major categories: Identified resources with a known location, quantity, and quality. Reserves are identified resources that can be extracted profitably at current prices. Undiscovered reserves are potential supplies of a mineral resource assumed to exist. Other resources are undiscovered resources and identified resources not classified as reserves.

The Life Cycle of a Metal Resource

Copy Figure 14-15 in your notes

There Are Several Ways to Remove Mineral Deposits Surface mining Shallow deposits removed Subsurface mining Deep deposits removed Overburden – the soil and rock overlying a useful mineral deposit Spoils – the overburden that is discarded as waste material

There Are Several Ways to Remove Mineral Deposits Types of surface mining Open-pit mining – machines dig holes and remove ores Strip mining – gigantic earthmovers strip away the overburden, and power shovels remove the mineral deposit Contour mining – is used mostly to mine coal on hilly or mountainous terrain Mountaintop removal – explosives, large power shovels, and huge machines are used to remove the top of a mountain and expose coal

Open-Pit Mine in Western Australia

Contour Strip Mining Used in Hilly or Mountainous Region

Mountaintop Coal Mining in West Virginia, U.S.

Mining Has Harmful Environmental Effects Scarring and disruption of the land surface E.g., spoils banks Loss of rivers and streams Subsidence – collapse of land above some underground mines Major pollution of water and air Effect on aquatic life Large amounts of solid waste

Banks of Waste or Spoils Created by Coal Area Strip Mining in Colorado, U.S.

Illegal Gold Mine

Ecological Restoration of a Mining Site in New Jersey, U.S.

Natural Capital Degradation: Summitville Gold Mining Site in Colorado, U.S.

How Long Will Supplies of Nonrenewable Mineral Resources Last? Objective 4 How Long Will Supplies of Nonrenewable Mineral Resources Last?

Mineral Resources Are Distributed Unevenly Most of the nonrenewable mineral resources are supplied by United States Canada Russia South Africa Australia

Future supply depends on Supplies of Nonrenewable Mineral Resources Can Be Economically Depleted Future supply depends on Actual or potential supply of the mineral Rate at which it is used When it becomes economically depleted Recycle or reuse existing supplies Waste less Use less Find a substitute Do without

Depletion Curves for a Nonrenewable Resource

Read the case study on page 363 The U.S. General Mining Law of 1872 Encouraged mineral exploration and mining of hard-rock minerals on U.S. public lands to boost development on the then-sparsely populated West Until 1995, land could be bought for 1872 prices Companies must pay for clean-up now

Is Mining Lower-Grade Ores the Answer? Factors that limit the mining of lower-grade ores Increased cost of mining & processing larger volumes of ore Availability of freshwater needed to mine and process some minerals Environmental impact Land disruption, waste materials, and pollution produced Improve mining technology Use microorganisms to extract minerals in-place or in situ in SY-too mining Downside is that it is a slow process Biomining Genetic Engineering techniques that can produce bacteria

How Can We Use Mineral Resources More Sustainably? Objective 5 How Can We Use Mineral Resources More Sustainably?

We Can Find Substitutes for Some Scarce Mineral Resources Materials revolution New materials are being used as replacements for metals For example, development of silicon and ceramics may replace the need for as much metal. Nanotechnology – tiny tech Uses science and engineering to manipulate and create materials out of atoms and molecules.

We Can Recycle and Reuse Valuable Metals Recycling Lower environmental impact than mining and processing metals from ores Example – Recycling aluminum beverage cans and scrap aluminum produces 95% less air pollution and 97% less water pollution and uses 95% less energy than mining and processing aluminum ore. Growing signs point to an ecoindustrial revolution taking place over the next 50 years. The goal is to make industrial manufacturing processes cleaner and more sustainable by redesigning them to mimic how nature deals with wastes.

Copy Figure 14-24 in your notes

An Industrial Ecosystem in Denmark Mimics Natural Food Web

Can you answer these questions? 1. Which rock type is made from lava? Igneous 2. Which rock type is made from lithified sediments? Sedimentary 3. Which rock type is made from the compression of the two other rock types? Metamorphic 4. Which mechanical process leads to the formation of sediment? Weathering 5. What are the two types of igneous rocks? Granite (formed underground) & lava rock (formed aboveground)

Summary Briefly describe the three major classes of rocks, including how they are formed and examples of each type. Explain what it means for a mineral to become economically depleted.