1. Potential Environmental Problems
 A. Mining operation itself
– Disposal of a large amount of rock and waste
– Noise
– Dust
 Beneficiation
 Smelting and refining

2. From Underground Mining
 Subsidence
– Block/caving
– Room and pillar
– Salt mining

3. Subsidence in rancher’s field

4. Subsidence from Pb-Zn mining

5. From Underground
 Acid Mine Drainage
– FeS minerals in coal
– Sulphide deposits
– Acidic streams can pick up heavy elements
and transport them

6. Rock that has acid forming material

7. Drainage

8. Acid and open pits
Berkley Pit

10. Other problems with open pits
 Very large holes
 Pit slopes steep and not stable. Cannot
be maintained
 May fill with water
 Strip coal mines –loss of top soil in past
– Now smoothed out and top soil added

11. Disposal of Waste Rock
 More problematic for open pit than
underground
 Waste rock piles have steep angle of
repose and thus may not be stable
 Bingham in its hay day produced 400,000
tons of waste rock per DAY!

12. Tailings ponds
 From concentrating usually have high pH
– At Bingham acid waters mixed with tailings
water to neutralize
 Different metals have different problems

13. Problems with Smelting/Roasting
 Air: SO2 and CO2 and particulate matter
 Noranda Quebec used to have the highest
single point source of SO2 in the world. It
may have been surpassed.
 CN (Au); NaOH and F (Al); solvents
(electrotwinning); heavy metals; oil and
grease

14. Environmental Impact
 Environmental impact
– From mineral exploration and testing
– From mineral mining
– From mineral resources refining
– From mining waste disposal

15. Environment Impact of Mineral
Development
 The impact depends upon many factors:
– Mining procedures
– Hydrologic conditions
– Climate factors
– Types of rocks and soils
– Topography
 Also population: NIMBY

16. Impact of Mineral Exploration and Testing
 Mineral exploration and testing
– Surface mapping, geochemical, geophysical, and
remote-sensing data collection
– Test drilling
 Impact
– Generally minimal impact
– More planning and care needed for sensitive
areas (arid, wetlands, and permafrost areas)

17. Impact of Mineral Extraction
and Processing (1)
General impact
 Direct impact on land, water, air, and
biological environment
 Indirect impact on the environment:
Topographic effect, transportation of
materials, etc.
 Impact on social environment: Increased
demands for housing and services

18. Impact of Mineral Extraction
and Processing (2)
 Impact from mining operations
– Land disturbances;Berk eley Pit.km
e.g., z
– Waste from mines: 40% of the mining area for waste
disposal, mining waste 40% of all solid wastes; e.g.,
,
– Special mining, e.g., chemical leaching from gold mining;
e.g.,
– Mining acid drainage, during mining and post-mining; e.g.,
New World district
Chico placer.kmz
ASARCO tailings.kmz
Golden Sunlight.kmz

19. Mclaren tailings.kmz

20. Impact of Mineral Extraction
and Processing (4)
 Water pollution
– Trace elements leaching out into water, such
as Cd, Co, Cu, Pb, Mo, Zn
– Flooding of abandoned mines, oxidation of
sulfide ores = sulfuric acid
– Acid mine drainage from tailings

21. Pollution of water from mining

22. Minimizing the Impact of Mining
(1)
 Knowledge and technology transfer: developed
countries to developing countries
 Environmental Regulations: Forbid bad mining
practices, Clean Air Act, and on- and offsite
treatment of wastes
 Land reclamation: About 50% of land used in mining
industry reclaimed
 Use of new biotechnology in mining: Bio-oxidation,
bioleaching, biosorption, genetic engineering

23. Minimizing the Impact of
Mining (2)
Figure 14.14

24. Recycling Mineral Resources
(1)
 Why recycle? Consider the impact of the
wastes
– Toxic to humans
– Dangerous to natural ecosystems
– Degradation of air, water, and soil
– Use of land for disposal
– Aesthetically undesirable

25. Recycling Mineral Resources
(2)
 Waste contains recyclable materials
 Saves energy, money, land, raw mineral
resources from more mining
 Saves energy and money when recycling
instead of refining raw ore materials
 Recycling has been proven to be profitable
and workable

26. Recycling Mineral Resources (3)
 Most-recycled metals: Iron and steel, 90% by
weight
 One-third as much energy needed to produce
steel from recycled scrap as from original ore
 More than $40 billion produced from recycled
metals in 1998
 Other recycled metals: Lead (63%), aluminum
(38%), and copper (36%)

27. Life cycle of a metal resource

28. Minerals and Sustainability
 Sustainability: long-term strategy for
consuming the resources
 Find an alternative material for the metal,
e.g., glass fiber cable for copper wires
 Use raw materials more efficiently
 More R&D on innovative substitutes or ways
to keep the R/C ratio, a solution to the
depletion of nonrenewable resources

29. Applied and Critical Thinking
Topics
 Considering the fact that mineral resources are
nonrenewable, do you believe that technology will
eventually help to meet the growing demand for mineral
resources? If yes, explain.
 Biotechnology shows the potential for cleaner minerals
extraction and waste disposal. Will biotechnology bring
about any environmental problems?
 What types of environmental impact would occur if
we increasingly extract more mineral resources from the
seafloor?