Transcript Chapter 15

Chapter 16
Minerals: A
nonrenewable
resource
Minerals
Elements or compounds that occur
naturally within the Earth’s crust.
Ex- Al, Cu, Mg, Zn, Fe, S, K, P
Sulfides: mineral compounds that
contain sulfur in addition to other
elements.
Oxides: mineral compounds that contain
oxygen in addition to other elements.
Minerals
General mining law (1872)
encouraged settlement in
western states.
Settlers could stake mining
claims on federal land.
.
Recently, a Canadian company
(ASARCO) paid almost nothing
for land worth billions $$$$.
(The land has large Cu and Ag
deposits)
http://www.asarco.com/AMDC/home.html
General mining law (1872)
has no provisions for:
• Environmental protection
•Replacement of topsoil/plants
•Clean-up of tailings
•Profit sharing with taxpayers
As a result 19,000km
(11,800 mi) of streams totally lifeless.
General mining law (1872)
More than 50 of the 100,000
to 500,000 abandoned mines
in the US are designated
Superfund sites.
In 2000…
• Congress voted to tighten up on Mining act
of 1872.
• George Bush has worked to weaken this
legislation…jobs??
Rocks: Naturally formed aggregates
(mixtures of minerals).
Ores: contain proportionally large
amounts of particular minerals that
can profitably mined.
High grade ores: contain large
amount of minerals.
Low grade ores: contain relatively
small amounts of minerals.
Metals: minerals that are malleable,
lustrous, and good conductors (heat
& electricity).
Nonmetals: minerals that are
nonmalleable (brittle), dull, and poor
conductors (heat & electricity).
There are 4 ways in which
mineral deposits are
formed…
•
•
•
•
Magmatic concentration
Hydrothermal processes
Sedimentation
Evaporation
Magmatic Concentration: results in
minerals that are malleable, lustrous,
and good conductors (heat &
electricity).
As Magma cools it solidifies and
separates into layers with the heavier
Fe & Mg (Magnesium oxides) rocks
settling towards the bottom.
examples: Fe, Cu, Ni, and Cr
Hydrothermal Processes
• These processes involve groundwater that has been
heated in the earth.
• Water (Polar molecule) is the universal solvent.
This water seeps through cracks and fissures and
dissolves certain minerals.
• The dissolving properties of water are better if Cl
and F are present. Cl and F often react to create
salts. Salts are soluble in water but when salts react
with Sufur, metal sulfides are produced and are not
soluble in water. These materials are then
deposited.
• These processes deposit Au, Ag, Cu, Pb, & Zn.
Sedimentation
• Weathered particles form sediments that are
deposited on riverbanks, deltas, & the sea
floor.
• Sedimentation has created important
deposits of Fe, Mn, P, S, Cu and other
minerals.
Evaporation
• Liquid water becomes gaseous and leaves
minerals that were in solution behind in the
remaining water.
• NaCl (Salt), borax (Sodium borate), K salts,
& gypsum have been found in large
quantities in rock layers.
Mining
Surface Mining: Extraction of
surface minerals.
Subsurface Mining:
Extraction of sub surface
minerals.
Mining
Surface Mining: more common due
to decreased cost of mineral
removal.
Two types:
Open-pit mining: Quarries
Strip mining: (strips & spoil banks)
Subsurface Mining:
Shaft mines create vertical shafts to
access the ore.
Slope mines: create a slanted
passage to access minerals.
Processing minerals:
Smelting: Mineral ores are melted at
high temperatures to help separate
impurities from liquid (molten)
metals.
Blast
Furnace
Environmental Issues which result
from Mining:
• Destruction of land (22 million acres)
• Removal of water from aquifer
• Destruction of water quality…tailings
(Acid mine drainage)
Ex.- Copper Basin in Tennessee
Surface Mining Control and
Reclamation Act of 1977
• Requires coal mines to reclaim “derelict”
lands
• Makes no provisions for other types of
mines
US and Canada have 5% of the world’s
population, but consume 25% of its metals.
Mineral Reserves vs.Mineral Resources?
Estimates vary widely!!
Minerals in Antarctica
• Antarctic Treaty of 1961 limits activity to
peaceful, scientific work.
• In 1989, the treaty was amended with the
Madrid Protocol…No exploration for the
next 50 years
How can we preserve or
increase our mineral
holdings?
Recycling
Conservation
Ocean mining?
Dematerialization
Change mineral
requirements
Dematerialization
The 1st electronic calculator/computer
was built at the University of Pennsylvania in 1946.
It weighed 27 metric tons (30 tons),
occupied 167m2 of floor space, & required
6 full time technicians to operate it.
What are the 3R’s that promote
sustainable manufacturing?