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