Download Nonrenewable Mineral Resources

ES 10 October XX, 2012
Some important points from last Thursdayday:
• Practice all definitions.
• List / discuss examples of all internal & external processes
• Understand general concepts of Plate Tectonics: SFS, plate
boundaries, locations, examples, associated geologic hazards and
resources
• Discuss / describe 5 common Geologic Hazards (focus on Equakes, Tsunamis and Mass Wasting)
• What can we do to reduce damage? Make a list here for each one.
• Describe all types of E-Quake Waves: how are they useful?
• Damage from E-Quakes, a function of what?
• What causes Tsunamis? Where most likely to occur?
• Main causes of Mass Movement? How do humans make things
worse? Why Santa Cruz Mountains so susceptible?
• Also look over Volcanoes and Coastal Processes
Key terms and study guide for
SOIL AND SOLID NON-FUEL MINERAL RESOURCES
Au
Cu
SnO2
Gabbro
Marble
Slate
Resources
Perpetual
Direct
solar
energy
Nonrenewable
Winds,
tides,
flowing
water
Fossil
fuels
Fresh
air
Fresh
water
NonMetallic
minerals
& rocks
Metallic
minerals
(iron, gold,
copper,
aluminum)
Renewable
Fertile
soil
or “Nonrenewable
Mineral Resources”
(clay, sand,
marble, slate)
These two are
sometimes
Called: “Solid
Nonfuel
Mineral
Resources”
What’s Environmental
Degradation?
Plants and
animals
(biodiversity)
Nonrenewable Mineral Resources: a definition
Concentrations of solid, liquid or gaseous
materials in or on the earth’s crust that can
be converted to useful materials at an
affordable price.
Occurring in fixed quantities……..
Fig. 1.11, p. 11
1
Rock Cycle
(Web Link: please read about this: http://imnh.isu.edu/digitalatlas/geo/basics/diagrams.htm)
A series of events through which a rock changes between igneous, sedimentary and
metamorphic forms. Cycle takes millions of years and is responsible for concentrating
Earth’s Nonrenewable Mineral Resources.
Part I: Soil
A Renewable Resource
– Definition……..
– Most valuable natural resource after water?
– Although renewable, it is produced very slowly,
if topsoil erodes faster than it is renewed, soil becomes a
nonrenewable resource.
– Most of the world’s crops are grown on cleared grassland
(e.g. US Midwest) and deciduous forest soils.
Factors determining type of soil and rate
of development:
•
•
•
•
•
Residual and Transported Soil
Parent Material
Slope
Climate
Plants & Animals
Time
2
Soil Profile:
Soil Erosion
– Natural process/rock cycle that occurs to all soils
– Causes (human activities):?
farming, logging, mining, construction, overgrazing,
urbanization, clear-cutting, fires, off-road vehicles
Mature soils have
distinct layers or zones
called
Soil Horizons;
cross-sectional views
of soil horizons are
called Soil Profiles.
Case Study:
Colorado
Kansas
“Dust
Bowl”
Oklahoma
New Mexico
Areas of serious concern
Areas of some concern
Texas
Stable or non-vegetative areas
Estimated Rates of Soil Erosion:
Before Humans: ~9 billion metric tons/yr
Current estimates ~24 billion metric tons/yr
MEXICO
3
Soil Erosion Continues to be a Concern
• The US is losing soil 10 times faster -- and China and India are
losing soil 30 to 40 times faster -- than the natural replenishment rate.
Source: Cornell University
• Estimated that ~8.1 million Km2 (12 times size of Texas) desertified
in the last 50 years. Each year an area the size of ~Greece.
• Human activity causes 10 times more erosion of continental surfaces
than all natural processes combined.
•
http://www.sciencedaily.com/releases/2004/11/041103234736.htm Web Link
Soil Conservation: reducing soil erosion and restoring soil
fertility
• Conservation tillage
farming: disturb soil as little as
possible; machines till subsurface
soil w/out breaking up topsoil or
inject seeds into unplowed soil. As
of 2004 used on ~38% of US
cropland. (USDA)
• Terracing: converting a slope
into a series of step-like platforms;
retains water and reduces erosion.
• Crop Rotation: successive
• The economic impact of soil erosion in the United States costs the nation about
$37.6 billion each year in productivity losses. Damage from soil erosion
worldwide is estimated to be $400 billion per year.
•
http://www.news.cornell.edu/stories/March06/soil.erosion.threat.ssl.html Web Link
planting of different crops in the
same area to improve soil fertility
and help control insects, diseases
and erosion.
Soil Conservation: reducing soil erosion and
restoring soil fertility
• Contour farming:
planting crops in rows that run
perpendicular to slope of land;
can reduce soil erosion by 3050% on gentle slopes.
• Strip cropping and
Intercropping: alternating
rows of two or more crops; keeps
soil covered and reduces erosion,
legumes restore soil fertility.
Dave, it better be no later than 11:40am…
Table 5-2, p.143
4
Resources
Part II: Solid Nonfuel Mineral Resources
Perpetual
Au
Cu
Nonrenewable
SnO2
Direct
solar
energy
Winds,
tides,
flowing
water
Fossil
fuels
NonMetallic
minerals
& rocks
Metallic
minerals
(iron, gold,
copper,
aluminum)
(clay, sand,
marble, slate)
Gabbro
Renewable
Marble
or “Nonrenewable
Mineral Resources”
Slate
How are solid non-fuel mineral resources formed and concentrated?
Most of the world’s major metal deposits occur at past or present plate
boundaries. Surface processes also play an important role in
concentrating nonmetallic minerals and rocks.
Fresh
air
Fresh
water
Fertile
soil
These two are
sometimes
Called: “Solid
Nonfuel
Mineral
Resources”
What’s Environmental
Degradation?
Plants and
animals
(biodiversity)
Fig. 1.11, p. 11
Magmatic Rocks & Minerals
granite, diorite, quartz, feldspar, chromite,
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits: wind, water, placers
– Evaporites
– Secondary Enrichment
Fig. 12-19a, p.351
5
Common Magmatic Rock / Mineral Resources & Their Use
• Granite / Diorite / Gabbro: building materials, dimension stone,
roads, shoulders, furniture, counter tops, interior/exterior surfaces
• (FeMg)Cr2O4 Chromite: important ore of chromium, used to
harden and manufacture steel, coloring agent, making bricks,
tanning leather, dyes, also used in common materials such as cars,
planes, engines, satellites, weapons, home appliances (form from
basaltic magmas)
• Opal (Quartz): gems, abrasives, mortar, glass, silica brick,
porcelain, paints, sandpaper, scouring soaps, wood filler, radios,
watchesl
• Platinum, Magnetite, Cobalt and Manganese: also used in
manufacturing cars, planes, engines, satellites, weapons, home
appliances (form from basaltic magmas)
Hydrothermal Deposits
Metallic chemical elements, Sulfides and Oxides form
in association with magma and water.
Hydrothermal deposits often occur in “veins”
Disseminated deposits
e.g. Au rich deposits of CA Sierra Nevada.
Black Smokers (undersea hot springs) form at Oceanic
Ridges (divergent plate boundaries) and at undersea hot
spots.
Formation of Metals: Hydrothermal and Magmatic
Read this Figure over very carefully
Know these symbols / names:
Fe = Iron
Au = Gold
Ni = Nickel
Cu = Copper
Pb = Lead
Zn = Zinc
Ag = Silver
Sn = Tin
Cr = Chromium
Iron
Copper
Zinc
Lead
Au, Cu
Fe
Pb, Zn, Ag, Cu
Fe
Sn
Pb, Zn,
Au, Ag, Cu
Sn
Cu
Iron
Chromium
Nickel
6
Common Hydrothermal Mineral Resources & Their Use
Hydrothermal Activity
Black smokers (undersea hot
springs) form at mid-ocean
ridge/divergent boundaries.
• Fe / Iron: bikes, cars, bridges, magnets, machines, nails, tools, food
supplements
• Fe / Hematite (Fe2O3 ): ore of iron, pigments, polishing powder, jewelry
• Au / Gold: circuit boards, electronics, jewelry, planes, space shuttles, compact
discs, cameras, telephones
• Cu / Copper: electrical purposes, circuit boards, wire, sculpture,
brass = Cu and Zn, bronze = Cu + Sn and some Zn, German silver
• Pb / Galena (PbS): lead sulfide, major source of lead, used in making
metals, pipe, sheets, solder, glass
• Zn / Sphalerite (ZnS): ore of zinc, important metal alloy used in making
Hydrothermal vein deposits. e.g.
rich Au deposits of CA Sierra
Nevada.
brass, paint, zinc oxide, batteries
• Ag / Silver: photographic film and paper, photosensitive glass, mirrors,
batteries, silverware
• Sn / Tin: metals, coins, cups, plates, cans, solder, opalescent glass, enamel,
weather resistant vinyl siding
How are solid non-fuel mineral resources formed and concentrated?
Metamorphism
Most of the world’s major metal deposits occur at past or present plate
boundaries. Surface processes also play an important role in
concentrating nonmetallic minerals and rocks.
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits
– Evaporites
– Water / Placer deposits
– Secondary Enrichment
7
How are solid non-fuel mineral resources formed and concentrated?
Most of the world’s major metal deposits occur at past or present plate
boundaries. Surface processes also play an important role in
concentrating nonmetallic minerals and rocks.
Sand Mining in Monterey Bay has been occurring
since 1906, ~150,000 – 250,000 cubic yards/yr,
with no regulation until 1960s.
3 companies for ~80 years, only one is left.
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits: wind, water, placers
– Evaporites
– Secondary Enrichment
A connection between mining and shoreline erosion
was determined in the mid
1980s, but still 1 company
mines ~235,000 cubic yards
each year.
Sand Mining in Monterey Bay
(web link)
Sedimentary Deposits: Sand and gravel accumulate in river
channels and bars, coastal offshore bars, sand dunes, beaches and
glacial outwash plains.
After deposition sediments lithify by compaction and cementation.
Materials used for: road beds, cement production, bricks, tiles, abrasives,
water filtration, glass production…..
“Point Bars”
Placer Deposits
Read this slide over very carefully.
8
Evaporites: (Salts: halite, gypsum, borates) water evaporates
from shallow inland seas in warm arid climates.
Materials used in: making glass, ceramics, metals, preservatives,
cleaning agents, water softeners……..
How are solid non-fuel mineral resources formed and concentrated?
Most of the world’s major metal deposits occur at past or present plate
boundaries. Surface processes also play an important role in
concentrating nonmetallic minerals and rocks.
• Internal Processes (magma generation, hot water circulation,
pressure & heat)
– Magmatic deposits
– Hydrothermal deposits
– Metamorphism
• External Processes (weathering, erosion, transport and deposition
by wind and water; evaporation)
– Sedimentary deposits: wind, water, placers
– Evaporites
– Secondary Enrichment
How are mineral resources found?
Understand the geologic/plate tectonic history of an area
Make Maps: rock formations, faults, structure
Drill, extract and analyze rock/sediment samples
Aerial photos and satellite images,
reveals outcrops and types of rock types
Seismic & gravitational surveys give
info about buried rock layers
Chemical analysis of water and plants
to detect minerals leached into water and
absorbed by plants
Remote sensing: (detect /analyze wave
transmitted energy) reveals outcrops and
types of rock
Secondary Enrichment
Measure radiation, magnetism to detect
radioactive metals, iron and other
9
How are Mineral Resources Extracted?
More Surface Mining
2) Hydraulic Mining: wash away overburden on hillsides;
mine uplifted placer deposits. In CA huge volumes of sediment
washed into SF-San Joaquin delta harming
navigation and agriculture, ~ 1850’s – 1890’s.
• Surface Mining
machines strip away millions of
tons of “Overburden” (rock/earth
covering ore) and pile it up as
waste material sometimes called
“Spoil”
~13 billion cubic
yards of sediment
has been washed
away from the
Sierra Nevada!
1) Open-pit mining:
commonly used surface mining
technique; used for mining most
major metal deposits, also sand,
gravel and stone.
The Palabora open pit in NE South Africa. The hard rock
allows the pit walls to be cut much steeper than is
normal in open-pit Copper mining.
3) Dredging: used on underwater mineral deposits;
gold mining of CA riverbed sediments until 1960s;
leaves great piles of spoil alongside channels called
spoil banks/dredge fields.
How are ores processed?
• Remove undesired parts of ore (gangue)
• Smelting extracts metals from other elements
• Pure metal is then converted to desired product by manufacturing
companies
Drawbacks? Results in air, water, soil pollution; solid and liquid
hazardous wastes; safety and health hazards
10
Smelting or “Extractive Metallurgy”
Why do we mine?
is the practice of extracting metal from ore, purifying it, and recycling it
Concerns? Environmental degradation from mining and processing, depletion
time, economic depletion, exhaustion, import dependence, high cost
Separation
of ore from
gangue
Metal ore
Start Here:
Surface
Mining
Melting
metal
Recycling
Conversion
to product
Discarding
of product
Scattered in environment
Supply and Consumption of Mineral Resources
Mine, use, throw away;
no new discoveries;
rising prices
B
Production
• Economic Depletion
– Costs more to find, extract, transport and process mineral than
deposit is worth.
– Options: 1) recycle or reuse existing supplies, 2)waste less, 3) use
less, 4) find substitute, 5) do without.
• Depletion Time:
– time it takes to use up 80% of reserves of a mineral at a given rate
of use.
• US currently imports ~50% of its most important non-fuel minerals.
– Used faster than they can be produced here
– Foreign ores are higher grade and can be extracted cheaper than
US reserves
A
Present
Recycle; increase reserves
by improved mining
technology, higher prices,
and new discoveries
Recycle, reuse, reduce
consumption; increase
reserves by improved
mining technology,
higher prices, and
new discoveries
C
Depletion
time A
Depletion
time B
Depletion
time C
Time
11
Mineral and Soil Resources
• Greatest concern about
mining solid non-fuel mineral
resources is environmental
degradation caused by
extracting, processing and
manufacturing.
• As resources become depleted
and lower grade ores are
mined, environmental
degradation increases.
• Soil is a renewable resource if
sound, sustainable agricultural
practices are used. When soil is
depleted of its nutrients or topsoil
erodes faster than it is replenished,
soil becomes a nonrenewable
resource.
• Soil loss seriously compromises
our ability to grow food necessary
to feed an expanding human
population.
12