Unit IV: Mining (Chapter 8)

Bozeman Science - Mining

What Do We Need?We need minerals!

● Valuable minerals (metals: iron, copper, gold, etc.)

● Fuel (i.e. coal)

● Non-metals (gravel)

Mineral Formation:

Distribution of Mineral Resources

● Tectonic Cycle, Rock Cycle, Soil Formation, Erosion

● Early Earth cooled and differentiated into distinct vertical zones

● Heavy elements sank toward core → lighter elements rose toward the crust

Mineral Distribution:

● Random distribution worldwide

● Full resource locations aren’t really fully known.

Minerals Are A Nonrenewable Resource!● Once the resources are used,

they’re gone for good in that region!

● These are the known quantities of resources that can be economically recovered.

● Within those reserves = Ores

● Ore: Naturally occurring solid material from which a metal or valuable mineral can be profitably extracted

Hubbert Curve for Oil:● This graph describes

global oil production and predicts the depletion of various natural resources.

● Notice, the US hit peak oil in the 1970s.

● One day soon, it will not be economically feasible to continue using oil!!

Peak is the theorized point in time when the maximum rate of extraction of oil is reached, after which it is expected to enter terminal decline.

Legislation

● Mining Act of 1872

○ Allowed individuals/companies to recover ores or fuels from federal lands

○ Prior to this act, the recovery of ores on public lands was technically illegal.

○ Written primarily to encourage development and settlement in the Western US

○ Contains very few environmental protection provisions ○ Consequences =

■ Abandoned mines■ Polluted waters

Types of Mining● Surface mining- removing minerals that are

close to Earth’s surface.○ Strip mining- removing strips of soil and

rock to expose ore.○ Open pit mining- the creation of a large

pit or hole in the ground that is visible from the surface.

○ Mountain top removal- removing the entire top of a mountain with explosives.

○ Placer mining- looking for metals and stones in river sediments.

Types of Mining● Subsurface mining:

○ Mining for resources that are at least 100 meters below Earth’s surface

○ Begins with a horizontal tunnel dug into the side of the mountain or feature containing the resource

○ Vertical shafts are drilled○ Elevators are used to bring miners down to resource and back

up○ Deepest = 2.2 miles○ Coal, diamonds, gold

Types of Mining

The Consequences of Mining

Mining Issues● Construction of roads● Soil erosion, damage to waterways, habitat fragmentation● Mountaintop Removal:

• Mining spoils deposited in adjacent valleys

• Can change or block flow of rivers

• Safer for workers than subsurface mining

• Try to restore mountain to original shape, BUT disagreement about whether reclamation efforts are effective

Mining IssuesSubsurface Mining

• Environmental impacts are less apparent than the visible scars left behind in surface mining

• But impacts include acid mine drainage• To keep from flooding need to be continually pumped

out• This water has very low pH• Can lower the pH of nearby soils and streams, causing

severe damage to the ecosystem

Mining Issues

● Dangerous occupation ● Accidental burial, explosions, fires ● Inhalation of gases and particles over long periods of time can

lead to respiratory diseases

○ Ex) Black Lung, forms of lung cancer● Today there are improved safety measures and less subsurface

mining ● HOWEVER in places like China, mining accidents are fairly

common

The Mining Production Process

Step 1: Survey, and stake a claim to YOUR land!

● Companies typically hire geologists to complete this process of searching for mineral deposits

● Next, assess whether the mining project would be economically feasible.

● Once permits, research, and approvals have been completed, you can then build your mining facility!

The Different Types of Coal

The Mining Production Process

Step 2: Recover the minerals.

● This is the process in which we extract the ore, using a variety of tools and machinery.

The Mining Production Process

Step 3: Processing

● The recovered minerals are processed through huge crushers or mills to separate commercially valuable minerals from their ores.

● Once processed, the ore is then sent to smelting facilities.

The Mining Production Process

Step 4: Smelting

● This process involves melting the concentrate in a furnace to extract the metal from its ore.

● The ore is then poured into moulds, producing bars of bullion, which are then ready for sale.

The Mining Production Process

Step 5: Closure and Reclamation

● Once a mining site has been exhausted of reserves, the process of closing the site occurs, dismantling all facilities on the property. The reclamation stage is then implemented, returning the land to its original state.

Before and After

Surface Mining Control and Reclamation Act of 1977

● Regulates surface mining of coal and the surface effects of subsurface coal mining

● Mandates that land be minimally disturbed during the mining process

● Reclaimed after mining is completed ● Does not regulate all of the mining practices that can

have harmful effects on air, water, and land ● Some laws address these issues:

○ Clean Air, Clean Water, and Superfund Acts...25

Some Key Mining Vocab:● Overburden/Spoil - the material that lies above an area that lends itself

to economical exploitation, such as the rock, soil, and ecosystem that lies above a coal seam or ore body

● Mine tailings - Tailings, also called mine dumps, culm dumps, slimes, tails, refuse, leach residue or slickens, terra-cone (terrikon), are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore.

● Gangue - the commercially worthless material that surrounds, or is closely mixed with, a wanted mineral in an ore deposit.

Infographic:

Mine Tailings:

In The News...

The Sky is Pink● Link● Documentary about Fracking● Take notes:

○ Things you learned○ How it relates to our mining chapter ○ How the protagonist, Josh Fox, asks you to question how we get our

information