A mineral resource is a concentration of naturally occurring material from the earth’s crust that can be extracted and processed into useful products and raw materials at an affordable cost. Found and extracted more than 100 minerals from the earth’s crust. Examples are fossil fuels (such as coal), metallic minerals (such as aluminum and gold), and nonmetallic minerals (such as sand and limestone). Minerals are classified as nonrenewable resources. An ore is rock that contains a large enough concentration of a particular mineral—often a metal—to make it profitable for mining and processing. Highgrade ore contains a large concentration of the desired mineral. Lowgrade ore has a smaller concentration. Aluminum (Al) is used for packaging and beverage cans and as a structural material in motor vehicles, aircraft, and buildings.
Lecture NONRENEWABLE MINERALS & ENERGY Outline Nonrenewable minerals • Mineral resources & Environmental effects of using them • Supplies & sustainable use of nonrenewable resources Energy • Fossil fuel • Renewable energy resources We use a variety of nonrenewable mineral resources • A mineral resource is a concentration of naturally occurring material from the earth’s crust that can be extracted and processed into useful products and raw materials at an affordable cost – Found and extracted more than 100 minerals from the earth’s crust – Examples are fossil fuels (such as coal), metallic minerals (such as aluminum and gold), and nonmetallic minerals (such as sand and limestone) – Minerals are classified as nonrenewable resources We use a variety of nonrenewable mineral resources • An ore is rock that contains a large enough concentration of a particular mineral—often a metal—to make it profitable for mining and processing – High-grade ore contains a large concentration of the desired mineral – Low-grade ore has a smaller concentration – Aluminum (Al) is used for packaging and beverage cans and as a structural material in motor vehicles, aircraft, and buildings We use a variety of nonrenewable mineral resources – Steel, an essential material used in buildings and motor vehicles, is a mixture (alloy) of iron (Fe) and other elements that are added to give it certain properties – Copper (Cu), a good conductor of electricity, is used for electrical and communications wiring – Gold (Au) is used in electrical equipment, tooth fillings, jewelry, coins, and some medical implants Some environmental impacts of mineral use • Metals can be used to produce many products • Life cycle of a metal—mining, processing, and using it— takes enormous amounts of energy and water and can disturb the land, erode soil, produce solid waste, and pollute the air, water, and soil • The more accessible and higher-grade ores are usually exploited first • As they are depleted, mining lower-grade ores takes more money, energy, water, and other materials, and increases land disruption, mining waste, and pollution Each metal resource that we use has a life cycle Surface mining Metal ore Separation of ore from gangue Smelting Melting metal Conversion to product Discarding of product Recycling There are several ways to remove mineral deposits • Shallow mineral deposits are removed by surface mining by: – Removing vegetation – Removing the overburden or soil and rock overlying a useful mineral deposit – Placing waste material set aside in piles, called spoils • Open-pit mining Open-pit copper mine There are several ways to remove mineral deposits • Strip mining is useful and economical for extracting mineral deposits that lie in large horizontal beds close to the earth’s surface – Area strip mining is used where the terrain is fairly flat; a gigantic earthmover strips away the overburden, and a power shovel removes the mineral deposit – Contour strip mining is used mostly to mine coal on hilly or mountainous terrain 10 Wind power has advantages and disadvantages 89 We can produce energy by burning solid biomass • Biomass consists of plant materials (such as wood and agricultural waste) and animal wastes that can be burned directly as a solid fuel or converted into gaseous or liquid biofuels • Solid biomass is burned mostly for heating and cooking, but also for industrial processes and for generating electricity 90 We can produce energy by burning solid biomass – Wood, wood wastes, charcoal (made from wood), animal manure – In agricultural areas, crop residues (such as sugarcane stalks, rice husks, and corn cobs) and animal manure are collected and burned – About 2.7 billion people in 77 less-developed countries face a fuelwood crisis and are often forced to meet their fuel needs by harvesting wood faster than it can be replenished – Plant fast-growing trees, shrubs, and perennial grasses in biomass plantations, but this can deplete soil nutrients and deplete or degrade biodiversity 91 92 Solid biomass has advantages and disadvantages 93 We can convert plants and plant wastes to liquid biofuels • Liquid biofuels such as biodiesel (produced from vegetable oils) and ethanol (ethyl alcohol produced from plants and plant wastes) are being used in place of petroleum-based diesel fuel and gasoline • Advantages of biofuels: – While oil resources are concentrated in a small number of countries, biofuel crops can be grown almost anywhere, and thus they help countries to reduce their dependence on imported oil 94 We can convert plants and plant wastes to liquid biofuels – If these crops are not used faster than they are replenished by new plant growth, there is no net increase in CO2 emissions, unless existing grasslands or forests are cleared to plant biofuel crops – Biofuels are easy to store and transport through existing fuel networks and can be used in motor vehicles at little or no additional cost • The two most water-intensive ways to produce a unit of energy are irrigating soybean crops to produce biodiesel fuel and irrigating corn to produce ethanol 95 We can convert plants and plant wastes to liquid biofuels • An alternative to corn ethanol is cellulosic ethanol, which is produced from inedible cellulose that makes up most of the biomass of plants – In this process, enzymes are used to help convert the cellulose from widely available inedible cellulose materials such as leaves, stalks, and wood chips to sugars that are processed to produce ethanol – A plant that could be used for cellulosic ethanol production is switchgrass, a tall perennial grass native to North American prairies that grows faster than corn – Affordable chemical processes for converting cellulosic material to ethanol are still being developed and are possibly years away 96 The cellulose in this rapidly growing switchgrass can be converted into ethanol, but further research is needed to develop affordable production methods 97 Advantages and disadvantages of liquid biofuels 98 Suggestions for transitioning to a more sustainable future 99 Energy conservation • Practice of reducing energy use to make fossil fuels last and to prevent environmental damage • Transportation: Gas-efficient cars and higher gas prices could help conserve energy • Personal choices: Individuals can save energy by turning off lights, taking public transit, and buying energy-efficient appliances Six big ideas • Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks, form deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis • The available supply of a mineral resource depends on how much of it is in the earth’s crust, how fast we use it, the mining technology used to obtain it, its market prices, and the harmful environmental effects of removing and using it • We can use mineral resources more sustainably by trying to find substitutes for scarce resources, reducing resource waste, and reusing and recycling nonrenewable minerals 101 Six big ideas • We should evaluate energy resources on the basis of their potential supplies, how much net energy they provide, and the environmental impacts of using them • Using a mix of renewable energy sources—especially solar, wind, flowing water, sustainable biofuels, and geothermal energy—can drastically reduce pollution, greenhouse gas emissions, and biodiversity losses • Making the transition to a more sustainable energy future will require sharply reducing energy waste, using a mix of environmentally friendly renewable energy resources, and including the harmful environmental costs of energy resources in their market prices 102 BACKGROUND READING 103 103 ... Nonrenewable minerals • Mineral resources & Environmental effects of using them • Supplies & sustainable use of nonrenewable resources Energy • Fossil fuel • Renewable energy resources We use a... ecologically restored, but such restoration is22rare Outline Nonrenewable minerals • Mineral resources & Environmental effects of using them • Supplies & sustainable use of nonrenewable resources Energy. .. supplies • Waste less or use less • Find a substitute or without 26 Market prices affect supplies of nonrenewable minerals • Geologic processes determine the quantity and location of a mineral resource