environmental effects

1. Environmental Effects ofEnvironmental Effects of
Using Mineral ResourcesUsing Mineral Resources

2. ENVIRONMENTAL EFFECTS OFENVIRONMENTAL EFFECTS OF
USING MINERAL RESOURCESUSING MINERAL RESOURCES
 The extraction, processing and use ofThe extraction, processing and use of
mineral resources has a very largemineral resources has a very large
environmental impactenvironmental impact

3. Fig. 15-10, p. 344
Natural Capital Degradation
Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources
StepsSteps Environmental effectsEnvironmental effects
Mining Disturbed land; mining
accidents; health hazards,
mine waste dumping, oil
spills and blowouts; noise;
ugliness; heat
Exploration,
extraction
Processing
Solid wastes; radioactive
material; air, water, and
soil pollution; noise;
safety and health
hazards; ugliness; heat
Transportation,
purification,
manufacturing
Use
Noise; ugliness; thermal
water pollution; pollution
of air, water, and soil;
solid and radioactive
wastes; safety and health
hazards; heat
Transportation or
transmission to
individual user,
eventual use, and
discarding

4. ENVIRONMENTAL EFFECTS OFENVIRONMENTAL EFFECTS OF
USING MINERAL RESOURCESUSING MINERAL RESOURCES
 GradeGrade – the percentage of metal content in an– the percentage of metal content in an
oreore

The lower the grade and accessibility, the higherThe lower the grade and accessibility, the higher
the: energy use, water use, land disruption, miningthe: energy use, water use, land disruption, mining
waste, pollution, effort, costwaste, pollution, effort, cost

5. ENVIRONMENTAL EFFECTS OFENVIRONMENTAL EFFECTS OF
USING MINERAL RESOURCESUSING MINERAL RESOURCES
 Mining methods vary widely in cost, safety andMining methods vary widely in cost, safety and
level of environmental harmlevel of environmental harm
 Different methods used based on mineralDifferent methods used based on mineral
depth:depth:

Surface miningSurface mining – removal of shallow deposits– removal of shallow deposits

Subsurface miningSubsurface mining – removal of deep deposits– removal of deep deposits

6. Surface MiningSurface Mining
 Used for 90% of nonfuel mineral and rockUsed for 90% of nonfuel mineral and rock
resources, 60% of coal in U.S.resources, 60% of coal in U.S.
 OverburdenOverburden – soil and rock above deposits– soil and rock above deposits

Removed along with forestsRemoved along with forests
 SpoilsSpoils – overburden that becomes waste– overburden that becomes waste

Can bury or contaminate streams andCan bury or contaminate streams and
groundwatergroundwater
 Several types:Several types:

7. Surface Mining: Open-pit MiningSurface Mining: Open-pit Mining
 Open-pit miningOpen-pit mining ––
machines digmachines dig
holes – removeholes – remove
ores, sand, gravelores, sand, gravel
and stoneand stone
 Toxic groundwaterToxic groundwater
can accumulate atcan accumulate at
the bottomthe bottom

8. Surface Mining: Strip MiningSurface Mining: Strip Mining
 Strip miningStrip mining - earth- earth
movers strips awaymovers strips away
overburden and giantoverburden and giant
shovels removesshovels removes
mineral deposits –mineral deposits –
esp. for minerals closeesp. for minerals close
to surface andto surface and
horizontalhorizontal
 Spoil banksSpoil banks – highly– highly
erodible hills of rubbleerodible hills of rubble
– no vegetation grows– no vegetation grows

9. Surface Mining: Strip MiningSurface Mining: Strip Mining
 Area strip miningArea strip mining – where terrain is flat– where terrain is flat
 Contour strip miningContour strip mining – if hilly or– if hilly or
mountainous terrain – leaves wall of dirt inmountainous terrain – leaves wall of dirt in
front of highly erodible bank (front of highly erodible bank (highwallhighwall))

10. Surface Mining: Mountaintop RemovalSurface Mining: Mountaintop Removal
 Mountaintop removalMountaintop removal ––
machinery removes tops ofmachinery removes tops of
mountains to expose coalmountains to expose coal
 Resulting waste rock andResulting waste rock and
dirt are dumped intodirt are dumped into
streams and valleys belowstreams and valleys below
 Esp. in W.Va. andEsp. in W.Va. and
KentuckyKentucky
 Lagoons of toxic coalLagoons of toxic coal
waste sludge – dams canwaste sludge – dams can
breakbreak

11. Surface Mining: Mountaintop RemovalSurface Mining: Mountaintop Removal
 Violation of Clean Water Act – ?Violation of Clean Water Act – ?
 No – Congress changed lawNo – Congress changed law
 Surface Mining Control and ReclamationSurface Mining Control and Reclamation
ActAct (1977) – requires mining companies to(1977) – requires mining companies to
restore – regrade and replant – rarelyrestore – regrade and replant – rarely
successfulsuccessful

12. The Land of Mountaintop Removal

13. Subsurface MiningSubsurface Mining
 Removes coal and metal ores that are tooRemoves coal and metal ores that are too
deep for surface miningdeep for surface mining
 Vertical shafts, tunnels and undergroundVertical shafts, tunnels and underground
chamberschambers
 Disturbs < 1/10Disturbs < 1/10thth
land area as surface mining,land area as surface mining,
less wasteless waste
 Much resource left in ground, moreMuch resource left in ground, more
dangerous (cave-ins, explosions, fires,dangerous (cave-ins, explosions, fires,
disease), more expensive, can contaminatedisease), more expensive, can contaminate
aquifersaquifers
 Subsidence can occurSubsidence can occur

14. U.S. General Mining Law of 1872U.S. General Mining Law of 1872
 Designed to help develop western U.S.Designed to help develop western U.S.
 Encouraged mineral exploration and miningEncouraged mineral exploration and mining
 Can file mining claim on public lands (exceptCan file mining claim on public lands (except
national parks and wilderness areas) –national parks and wilderness areas) –
spend $500 to “improve” for mineralspend $500 to “improve” for mineral
development, pay $120/year for 8 hectares =development, pay $120/year for 8 hectares =
20 acres – even if no mine is in operation20 acres – even if no mine is in operation
 1992 law modified to force companies to1992 law modified to force companies to
post bonds to cover clean up costs if gopost bonds to cover clean up costs if go
bankruptbankrupt
 Until 1994 – could buy land from governmentUntil 1994 – could buy land from government

15. Mining ImpactsMining Impacts
 Scarring and disruption of land surfaceScarring and disruption of land surface
 Subsidence – collapse of land aboveSubsidence – collapse of land above
subsurface minessubsurface mines
 Toxin-laced mining wastes to land, water,Toxin-laced mining wastes to land, water,
atmosphere – moved by wind or wateratmosphere – moved by wind or water
 Acid mine drainageAcid mine drainage – when rainwater– when rainwater
seeps through a mine or mine wasteseeps through a mine or mine waste
containing sulfuric acid (Hcontaining sulfuric acid (H22SOSO44) into streams) into streams
or groundwateror groundwater

16. Case Study: The Real Cost of GoldCase Study: The Real Cost of Gold
 At about 90% of the world’s gold minesAt about 90% of the world’s gold mines

Mineral extracted with cyanide saltsMineral extracted with cyanide salts

Cyanide is extremely toxicCyanide is extremely toxic
 Some mining companies declare bankruptcySome mining companies declare bankruptcy

Allows them to avoid environmental remediationAllows them to avoid environmental remediation

17. Mining ImpactsMining Impacts
 Gold King, ColoradoGold King, Colorado – 2015 – mine waste– 2015 – mine waste
water spill – 3 million gallonswater spill – 3 million gallons
 EPA and consultant workers caused spill ofEPA and consultant workers caused spill of
toxic wastewater while trying to fix tailingtoxic wastewater while trying to fix tailing
pond – contained cadmium, lead, arsenicpond – contained cadmium, lead, arsenic
 Local governments previously refusedLocal governments previously refused
Superfund $ – worried about tourism $Superfund $ – worried about tourism $

18. Mining ImpactsMining Impacts
 Gold King, ColoradoGold King, Colorado – Cement Creek →– Cement Creek →
Animus RiverAnimus River

19. Removing Metals from OresRemoving Metals from Ores
 After mining:After mining:

Ore mineralOre mineral – contains desired metals– contains desired metals

GangueGangue – waste materials– waste materials

TailingsTailings – large piles of solid waste made when– large piles of solid waste made when
gangue removed from ore – can entergangue removed from ore – can enter
atmosphere or wateratmosphere or water

SmeltingSmelting – extracting metal ores by heating or– extracting metal ores by heating or
with (potentially toxic) chemicals to extract thewith (potentially toxic) chemicals to extract the
desired metal – major air pollution esp. sulfurdesired metal – major air pollution esp. sulfur
dioxide (SOdioxide (SO22 – toxic, acid deposition), particulates,– toxic, acid deposition), particulates,
toxic chemicalstoxic chemicals
• Cyanide heap extractionCyanide heap extraction – cheap way to remove– cheap way to remove
metals from oresmetals from ores