Transcript Mining - Northwest ISD Moodle

Minerals and Mining
Minerals
• Concentration of
naturally occurring
elements in/on
Earth.
• Formed over
millions of yrs 
non-renewable
resource.
What We Mine?!?
• Metallic minerals: Iron, Copper, Aluminum
• Non-metallic minerals: salt, clay, sand
• Energy minerals: coal, oil, uranium
Crushed Iron
Sodium Chloride
Crystal
“Dur”rty Coal
Ore
• Rock that has
metallic
mineral.
• Usable stuff is
the mineral
• Non-usable is
called gangue
 landfill
Gold
Gangue
Smelters
• Used to remove mineral from gangue in an
ore  major polluters (Runescape!).
Bauxite
Most Important Aluminum Ore
Oxygen: The Most Abundant
Element in the Earth’s Crust
Finding Mineral Deposits
• Use aerial photos and satellite
images to see rock formations.
Finding Mineral Deposits
• Use planes w/ Geiger meter
(uranium) or magnetometer (iron)
Geiger
Meter…Only $460!
Magnetometer…
Only $700!
Finding Mineral Deposits
• Drilling a deep well and
extracting ore samples.
Exploration Drilling
Surface Mining Reclamation and
Control Act
• Mining ops must reclaim area after
land has been used and abused.
• Must put aside $$$ to reclaim before
mining op’s begin.
• States oversee Act.
• Land put back, trees grow, no toxic
runoff!
Surface Mining
• Minerals must be shallowly deposited.
• Removed rock and soil is called
overburden or spoil.
Types of Surface Mining
Open Pit Mining
• Dig hole and remove ores
• Fe, Cu, and Sand
Types of Surface Mining
Dredging (Sand)
• Draglines scrape up underwater
mineral deposits
Types of Surface Mining
Area Strip Mining
• Cut new strips away; spoil placed on side,
mineral taken out.
Types of Surface Mining
Mountaintop Removal
• Use TNT, huge shovels, and large machines
to remove top of a mtn and expose coal
underneath.
Case Study Gold: Cyanide Heap Leaching
• Cyanide
sprayed on low
grade gold ore
in a giant heap
(pile).
• Gold flows down
w/ cyanide and
is collected at
bottom of heap.
Heap
Case Study Gold: Cyanide Heap Leaching
• Toxic to birds
and mammals.
• Leach ponds
can overflow
 H2O
pollution
• Leaky liners?
Leach Liner
Subsurface Mining
• Used to
remove
minerals deep
in Earth’s
surface.
• Less env.
Impact
Types of Subsurface Mining
• Room and
Pillar
• Machines
are used to
cut out
minerals
and are
placed on a
shuttle car.
Scraper
Types of Subsurface Mining
• Longwall Coal
Mining
• Moveable steel
props support
cave while
machinery cut
off coal onto a
conveyor belt.
Environmental Damage
• Collapse/subsidence of land from
subsurface mines.
• Causes houses to tilt, sewer lines crack,
gas mains break.
Environmental Damage
• Wind/water carry away [by erosion] toxic
mining waste.
• Goes in food webs and watersheds.
Environmental Damage
Habitat Loss!!
My
Home!!!
Environmental Damage
• Transportation of minerals  global
warming, lung probs.
Environmental Damage
Acid mine drainage
• Bacteria eat FeS in spoil  create
H2SO4  runs off into streams