Rocks vs Minerals vs Metals RocksMineralsMetals HeterogeneousHomogeneous (set chemical formula)...
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Transcript of Rocks vs Minerals vs Metals RocksMineralsMetals HeterogeneousHomogeneous (set chemical formula)...
Rocks vs Minerals vs MetalsRocks Minerals Metals
Heterogeneous Homogeneous (set chemical formula)
Found on periodic chart but occur in nature as a compound at times
Solid Solid Solid
May be organic Always inorganic Always inorganic
May be man made Naturally occurring Naturally occurring
May have crystals Definite crystal shape Gold, copper, silver and other metals can form crystals
“Mutt” “Purebred” Might be smelted to get pure sample
Benefits of
Mining
Careers in Mining
Metal Uses Millions Metric Tons Annually
Iron Heavy machinery, steel production 740
Aluminum Packaging foods & beverages, transportation, electronics
40
Manganese High-strength, high-resistant steel alloys
22.4
Copper Building construction, electric/electroni industry
8
Chromium High strength steel alloy 8
Nickel Chemical industry, steel alloys 0.4
Lead Leaded gasoline, car batteries, paint, ammunition
Silver Photography, electronics, jewelry
Gold Medical, aerospace, electronic use, money, jewelry
Platinum Automobile catalytic converters, electronics, medical uses, jewelry-
Metal Resources
Metal Resources
Biggest Users of Metals United States Japan EuropeBiggest Producers South America South Africa Former Soviet Union .
Non-Metal Resources Sand & gravel (highest volume & dollar value than any
other non-metal & greater volume than metals) Uses: brick & concrete construction, paving, road filler,
sandblasting, glass (high silica content sand) Limestone
Uses: concrete, road rock, building stone, pulverized to neutralize acidic soil or water.
Evaporites- halite, gypsum, potash Uses: halite- rock salt for roads, refined into table salt Gypsum- makes plaster wallboard Potash- for fertilizer (potassium chloride, potassium sulfates)
Sulfur deposits Uses: sulfuric acid in batteries & some medicinal products
MO History of Iron Mining
"It is about a mile broad at the base, 400 feet high and three miles long; and has the appearance of being composed of masses of iron ore. It is literally a mountain of ore so pure that it yields from 70 to 80 per cent under the ordinary process of converting it into malleable iron. At the base the ore lies in pieces from a pound weight upward, which increases in size as you ascend, until they assume the appearance of huge rocks, which would remind the beholder of those "fragments of an earlier world" of which the Titians made use. Six miles southeast in another mountain called Pilot Knob, composed of a macaceous oxide of iron lying in huge masses. This ore will yield about 80 per cent of metal."
In the year 1843 a St. Louis newspaper published the following description of Iron Mountain in Pilot Knob:
Steps in Obtaining Mineral Commodities Prospecting- finding places where ores
occur Mine exploration & development- learn
whether ore can be extracted economically Mining- extract ore from ground Beneficiation- separate ore minerals from
other mined rock Smelting & refining- extract pure mineral
from ore mineral (get the good stuff out of waste rock)
Transportation- carry mineral to market Marketing & sales- find buyers & sell the
mineral
Types of Mining Surface- scoop ore off
surface of the earth or dig big holes and scoop Cheap Safe for miners Large amount of
environmental destruction Subsurface- use shafts
to reach deeply buried ores Expensive Hazardous for miners Less environmental
damage
Types of Surface Mining
1. Open Pit Mininga. Overlaying material
is removed using large equipment
b. Creates pits that are hundreds of meters wide and hundreds of meters deep.
Types of Surface Mining
2. Strip miningLike open pit but not
as deep of a pitSame environmental
damage
Large bucket wheel extractor being moved through Germany. Moves 10 meters per minute. Takes 5 people to operate. Used in strip mining
Types of Subsurface mining Variety of methods Photos of Limestone Mine, Ste.
Genevieve MO
Types of Subsurface Mining Dredging
Sand is removed from bottom of ocean
Can be done to restore beaches (after hurricane)
Destroys fragile benthic ecosystems
Mining IssuesMining Issues Mine Safety: In U.S., stringent mining regulations have lead to a reduction in fatalities, both in terms of total deaths per year, deaths per person-hour worked, and deaths per ton mined. surface
Health Problems mine collapse fire (methane, coal dust, etc.). asphyxiation (methane,
carbon monoxide) pneumoconiosis (from
inhaling coal dust) asbestosis (from inhaling
asbestos fibers) silicosis (from inhaling silicate
dust) heavy metal poisoning (e.g.
mercury) radiation exposure (in
uranium mining)
Environmental Damage Gaping holes in ground (old open pit mines) Accidental draining of rivers and lakes Disruption of ground water flow patterns Piles of gangue- mine tailings (mining waste) Loss of topsoil in strip-mined regions (350 to 2,700 km2 in US
alone) Spoil banks are where holes were filled in with waste- cheap &
easy- susceptible to erosion, chemical weathering, causes high sediment runoff in watersheds. Steep slopes are slow to re-vegetate (succession happens slowly- no topsoil)
Contamination of soil or water from heavy metals (e.g. arsenic, mercury) in mine tailings.
Contamination from sulfuric acid (H2SO4) produced through weathering of iron sulfide (FeS2, pyrite) in tailings. 4FeS2 + 14H2O = 4Fe(OH)3 + 8H2SO4
Water leaking into mine shafts, washes dissolved metals & toxic material into water sources. (550,000 abandoned mines in U.S.- 12,000 mi of rivers & streams
contaminated with mine drainage- cost to clean up $32-$72 billion)
Acid Mine Drainage
Acid Mine Acid Mine DrainageDrainage
The impact of mine drainage on a
lake after receiving
effluent from an abandoned
tailings impoundment
for over 50 years
Shoreline of a pond receiving AMD showing massive accumulation of iron hydroxides on the pond bottom
Mine effluent discharging from the bottom of a waste rock pile
(gangue) (Gangue may actually have a commercial use
so is no longer discarded as
tailings)
Coeur D' Alene Mine in Colorado
“Gangue”- mine tailings
Chat• fragments of siliceous rock,
limestone, and dolomite waste rejected in the lead-zinc milling operations that accompanied lead-zinc mining in the first half of the 20th century.
• Lots of chat piles remain in the Old Lead Belt covering about 110 square miles (280 km2) in southeastern Missouri.
• The first recorded mining occurred in the Old Lead Belt in about 1742. The production increased significantly in both the Tri-state area and the Old Lead Belt during the mid-19th century and lasted up to 1970.
https://en.wikipedia.org/wiki/Chat_(mining)
Although poisonous, chat can be used to improve traction on snow-covered roads; as gravel; and as construction aggregate, principally for railroad ballast, highway construction, and concrete production.
Surface Mining Control & Reclamation Act (SMCRA)
1977 Requires better restoration of
strip-mined lands Restoration is difficult &
expensive Takes long time for soil to
regain fertility Topsoil gets buried Compacted, poor drainage Root growth restricted
Minimum cost- $1000 per acre
Complete restoration (if possible)- $5,000 per acre
BeneficiationProcessing Mineral/metal
Two methods1. Smelting- heating ore to release
metala. Causes pollution (see next slide)b. Produces slag (waste) which must
be disposed of- may be toxicc. Releases small amounts of heavy
metal (As, Cd, Hg)2. Chemical treatment
a. Heap-Leaching- Used to separate gold from ore- Create huge piles of ore, spray
with dilute alkaline-cyanide solution, percolates thru pile to dissolve gold which is collected from runoff
- Supposed to have clay or plastic liners under pile
Summitville mine near Alamosa, Colorado was abandoned after the owners extracted $98 million in gold then declared bankruptcy in 1992. Will cost EPA $100 million to clean up
Georgia vs. Ducktown, TN(1915) In 1800’s began mining copper in
Ducktown, TN Built huge open air wood fires by
cutting down trees in area. Burned ore to release copper
Damage caused: Clouds of sulfur dioxide released
from burning sulfide ore poisoned plants & acidified soil.
Massive interstate air pollution Rain caused massive erosion Siltation of reservoirs on Ocoee
River impaired electricity generation by the Tennessee Valley Authority (TVA)
In 1930’s clean up began- spend $250,000 per year for clean up
Trees still spindly, but only 4% of area is still bare.
Now
1940’s
How can we conserve geologic resources? Recycling
Saves energy○ Recycling aluminum cans requires 1/20th the energy
than extracting aluminum from bauxite (aluminum ore)○ Only 2/3 of aluminum actually recycled○ See Table
Reduces need for mining which reduces overall environmental impact
Minimills becoming more common- remelt & reshape waste scrap iron & steel. Cost comparison: $225-$480 per metric ton while regular steel mills cost $1425-$2250 per metric ton.
“Mine” landfills to reuse materials
How can we conserve geologic resources? Substituting New Materials for Old
History: Stone age, bronze age, iron agePlastic PVC instead of copper, lead, steel
pipesFiber optic technology and satellite
communication reduces the need for copper telephone wires
Steel replaced by aluminum, polymers, alloys that reduce weight & cost, increase fuel efficiency in cars