Biology 4.1 Energy and Mineral Resources

Energy and Mineral Resources

Key Concepts What is the difference between renewable and

nonrenewable energy?

Which energy resources are fossil fuels?

Which energy resources might replace our vanishing oil supplies?

What processes concentrate minerals into deposits sufficiently large enough to be worth mining?

How are nonmetallic mineral resources used?

Mineral and Energy Resources

Mineral energy resources are the raw materials used to produce what we own, where we live, what we use and the energy to run it all.

Resources are broken into two categories

Renewable resources

Nonrenewable resources

Renewable Resource A renewable resource can be

replenished over fairly short time spans such as months, years, decades

Common examples are plants and animals for food, natural fibers for clothing, and trees for lumber or paper

Nonrenewable Resources

Nonrenewable resources are resources that take millions of years to form and accumulate

Examples of nonrenewable resources are oil, coal, natural gas as well as minerals such as iron, uranium, gold, and copper.

Fossil Fuels Nearly 90% of all energy used in

the United States comes from fossil fuels

A fossil fuel is any hydrocarbon that may be used as an energy source.

Fossil fuels include coal, oil, and natural gas.

Coal

Coal forms when heat and pressure transform plant material over millions of years

Coal passes through 4 stages of developmentStage 1: peat Stage 2: ligniteStage 3: bituminous coal or soft coalStage 4: anthracite or hard coal.

Coal Coal forms when heat and

pressure transform plant material over millions of years

Coal passes through 4 stages of development

Stage 1: Peat is partially decayed plant material that looks like soil

Coal Coal forms when heat and pressure

transform plant material over millions of years

Coal passes through 4 stages of development

Stage 2: Peat than becomes lignite, which is a type of sedimentary rock that is often called brown coal

Coal Coal forms when heat and pressure

transform plant material over millions of years

Coal passes through 4 stages of development

Stage 3: Continued heat and pressure transforms lignite into bituminous coal or soft coal which is another type of sedimentary rock

Coal Coal forms when heat and pressure

transform plant material over millions of years

Coal passes through 4 stages of development

Stage 4: Coal’s last stage of development is a metamorphic rock called anthracite or hard coal.

As coal develops from peat to anthracite, it becomes harder and burns hotter releasing more energy

Coal Power plants primarily use coal

to power generate electricity

Electric power plants account for 70% of the coal mined today

Coal The worlds coal reserves, supply of coal, is

enormous.

Although coal is plentiful in the US, it’s use still present two major problems . . . .

Coal Strip mining of coal leaves

surface scarring of the land.

Today, all US surface mines must restore the land surface when mining ends

Underground mining of coal is an alternative but is very dangerous and costly in comparison

Coal Burning of coal, which is high in

sulfur, creates air pollution problems

When burns, sulfur becomes sulfur oxides in the air. A series of chemical reactions turns the sulfur oxides into sulfuric acid, which falls to earth as acid rain

Petroleum and Natural Gas

Petroleum (oil) and Natural Gas form from the remains of plants and animals that were buried in ancient seas.

Petroleum formation begins when large quantities of plant and animal remains become buried in ocean-floor sediments.

The sediment protects these remains from oxidation and decay.

Over millions of years and continued sediment buildup, chemical reactions slowly transform these remains into liquid and gaseous hydrocarbons which we know as petroleum and natural gas.

Petroleum and Natural Gas

These materials are gradually squeezed from the compacting mud-rich sediment layers. The oil and gas than move into nearby permeable beds such as sandstone.

The oil and gas are than squeezed out of the sedimentary rock layers along with water.

However, oil and natural gas are less dense than water so they migrate upward through the water-filled spaces of the enclosing rocks.

If nothing stops the, the oil and gas will eventually reach the surface.

Petroleum and Natural Gas

Sometimes an oil trap, a geological structure that allows large amounts of gases-fluids to accumulate, stops upward movement of oil and gas.

Petroleum and Natural Gas

Several geological structures may serve as oil traps, but all have two things in common

A permeable rock reservoir that allows oil and gas to collect in quantities

An oil trap has a cap rock that is nearly impenetrable and so keeps oil and gas from escaping to the surface

Petroleum and Natural Gas

One structure that acts as an oil trap is an anticline

An anticline is an uparched series of sedimentary rock layers.

When a drill punctures the cap rock, pressure is released, and the oil and gas move toward the drill hole. Than a pump lifts the petroleum out.

Tar Sands and Oil Shale With our present dwindling oil

supply, many experts believe that fuels derived from tar sands and oil shales could become good substitutes for our present shrinking petroleum supply

Tar Sands Tar sands are usually mixtures of clay

and sand combined with water and varying amounts of a black, thick tar called bitumen.

Deposits occur in sands and sandstones, but also in shales and limestones.

The oil in these deposits is similar to heavy crude oils pumped from wells.

The oil in tar sands however is much more resistant to flow and cannot be pumped out easily.

Tar Sands Currently tar sands are mined at the

surface, much like the strip mining of coal. The excavated material is than processed removing impurities and refined as oil.

Extracting and refining oil from tar sand requires much energy; nearly half as much as the process yields.

With current oil prices, mining tar sand is not economically profitable. When prices rise however, this can change.

Tar Sands Extracting oil from tar sands does

have drawbacks other than the economic issues; several environmental concerns also exist.

Mining tar sands causes large scale land disturbances from strip mining, requires large amounts of water to be used, and produces wastes in the form of contaminated waters and toxic sediments.

Oil Shale Oil shale is a rock that

contains a waxy mixture of hydrocarbons called kerogen

Oil shale can be mined and heated to vaporize the kerogen. The kerogen vapor is than processed to remove the impurities and refined.

Oil Shale Roughly half the world’s oil

shale supply is in the Green River Formation in Colorado, Utah, and Wyoming.

Heat energy in oil shale is only about one-eighth that in crude oil. The processing requires large amounts of water. Current technology makes mining oil shale an unprofitable solution to the world’s oil shortage.

Formation of Mineral Deposits

Practically every manufactured product contains substances that comes from minerals.

Mineral Resources are deposits of useful minerals that can be extracted.

Mineral Reserves are deposits from which minerals can be extracted profitably

Ore is a useful metallic mineral that can be refined at a profit

Mineral Resources and Igneous Processes

I gneous p rocesses (p roduc ts o f ho t magma) p roduce impor tan t depos i t s o f meta l l i c m inera ls , such as go ld , s i l ve r, copper, mercury, lead , p la t inum, and n icke l .

For example , i f a la rge body o f magma coo ls , heavy m inera ls c rys ta l l i ze ear ly and se t t le to the bo t tom o f the magma chamber. Chromi te , magnet i te , and p la t inum somet imes fo rm th is way.

Hydrothermal Solutions Hydrothermal solutions generate

some of the best-known and most important deposit ores.

Many of the most productive gold, silver, and mercury deposits occur as hydrothermal vein deposits

Placer Deposits Placer deposits are formed when

eroded heavy minerals settle quickly from moving water while less dense particles remain suspended and continue to move.

Common sites of accumulation include the inside of the bends in streams, as well as cracks, depressions, and other streambed irregularities

Gold is the best know placer deposit

Nonmetallic Mineral Resources

Nonmetallic mineral resources are extracted and processed either for the nonmetallic elements they contain or for their physical and chemical properties

Examples of nonmetallic minerals are fluorite and limestone that are part of the steelmaking process and the fertilizers used to grow food