ch 11: nonrenewable resource use

mineral

• naturally occurring chemical element or inorganic compound that exists as a solid with regularly repeating internal arrangement of atoms or ions

*takes millions of years to form

*ex. salt, quartz

*we have never completely run out of a nonrenewable mineral resource, but a mineral becomes economically depleted when it costs more than it is worth to find

mineral resource

• concentration of one or more minerals in the earth’s crust that we can extract and process into raw materials and useful products at an affordable cost

rock

• combo of one or more minerals in the earth’s crust

• most rocks consist of two or more minerals

*ex. granite

sedimentary rock

• made of sediments—dead plant and animal remains and particles of weathered and eroded rocks

*increasing weight and pressure on the underlying layers transform the sedimentary layers to rock

*ex. sandstone, shale, dolomite, limestone, lignite, bituminous coal

igneous rock

• forms below or on the earth’s surface under intense heat and pressure when magma wells up from the earth’s mantle and then cools and hardens

*ex. granite, lava rock

*forms bulk of earth’s crust BUT covered by layers of sedimentary rock

metamorphic rock

• forms when an existing rock is subjected to high temperatures (which may cause it to melt partially), high pressures, chemically active fluids, or a combination of these agents

ex. slate (formed when shale and mudstone are heated) and marble (produced when limestone is exposed to heat and pressure)

rock cycle

• recycled over millions of years by three processes—erosion, melting, and metamorphism—which produce sedimentary, igneous, and metamorphic rocks, respectively

ore

• rock that contains a large enough concentration of a mineral—often a metal—to make it profitable for mining and processing

high-grade ore

• contains high concentration of mineral

reserves

• identified deposits from which we can extract the mineral profitably at current prices

depletion time

• time it takes to use up a certain proportion—usually 80%—of the reserves of a mineral at a given rate of use

rems

• scandium, yttrium, and 15 lanthanide chemical elements

• used to make LCD flat screens for computers and television sets, energy-efficient compact fluorescent and LED light bulbs, solar cells, fiber-optic cables, cell phones, and digital cameras

• also used to manufacture batteries and motors for electric and hybrid-electric cars, solar cells, catalytic converters in car exhaust systems, jet engines, and the powerful magnets in wind turbine generators

• also go into missile guidance systems, jet engines, smart bombs, aircraft electronics, and satellites

untapped sources

• seafloor mining from black smokers, precipitates that form when cold water and hot water from volcanic vents combine, and harvesting manganese nodules on the ocean floor

surface mining

• removing soil, subsoil, and other strata and then extracting a mineral deposit found fairly close to the earth’s surface

overburden

• layer of soil and rock overlying a mineral deposit

• waste material

spoils

• unwanted rock and other waste materials produced when a material is removed from the earth’s surface or subsurface by mining, dredging, quarrying, or excavation

• deposited in piles

open-pit mining

• type of surface mining

• machines are used to dig large pits and remove metal ores containing copper, gold , or other metals, or sand, gravel, or stone.

strip mining

• type of surface mining

• bulldozers, power shovels, or stripping wheels remove large chunks of the earth

area strip mining

• used on flat terrain, a gigantic earthmover strips away the overburden

• removes a mineral resource such as gold

• resulting trench is filled with overburden, and a new cut is made parallel to the previous on

contour strip mining

• mostly to mine coal and various mineral resources on hilly or mountainous terrain

• power shovels and bulldozers cut a series of terraces into the side of a hill

• then earthmovers remove the overburden, an excavator or power shovel extracts the coal, and the overburden from each new terrace is dumped onto the one below

mountaintop removal

• explosives are used to remove the top of a mountain to expose seams of coal

• after, enormous machines plow waste rock and dirt into valleys below

*destroys forests, buries mountain streams, and increases the risk of flooding

sludge

• gooey mixture of toxic chemicals, infectious agents, and settled solids removed from wastewater at a sewage treatment plant

subsurface mining

• underground mineral resources are removed through tunnels and shafts

*used to remove metal ores and coal that are too deep to be extracted by surface mining

*disturbs less than one-tenth as much land as surface mining, and usually produces less waste material

harms of surface mining

• cave-ins, explosions, and fires for miners

  • lung disease

• subsidence: collapse of land above underground mines

  • damage houses, crack sewer lines, break natural gas mains, and disrupt groundwater systems

acid mine drainage

• rainwater that seeps through an underground mine or a spoils pile from a surface mine carries sulfuric acid produced when aerobic bacteria act on remaining minerals to nearby streams and groundwater

gangue

• the waste material that is discarded when ore is extracted during mining

tailings

• the materials left behind when ore is separated from rock waste

• tailings can be left in piles, or flushed into ponds where fine particles then settle out

smelting

• process in which a desired metal is separated from the other elements in an ore mineral

*w/o effective pollution control equipment, a smelter emits large quantities of air pollutants, including sulfur dioxide and suspended toxic particles that damage vegetation and acidify soils in the surrounding area

*smelters also cause water pollution and produce liquid and solid hazardous wastes that require safe disposal

sustainable use of nonrenewable minerals

• Reuse or recycle metal products whenever possible

• Redesign manufacturing processes to use less mineral resources

• Reduce mining subsidies

• Increase subsidies for reuse, recycling, and finding substitutes