Earth Resources

Mineral Resources• Building

Stone, Sand, Gravel, Limestone

• Non-metallic MineralsSulfur, Gypsum, Coal,

Barite, Salt, Clay, Feldspar, Gem Minerals, Abrasives, Borax, Lime, Magnesia, Potash, Phosphates, Silica, Fluorite, Asbestos, Mica, Lithium

• Metallic Minerals– Ferrous: Iron and Steel,

Cobalt, Nickel

• Metallic Minerals– Non-ferrous: Copper, Zinc,

Tin, Lead, Aluminum, Titanium, Manganese, Magnesium, Mercury, Vanadium, Molybdenum, Tungsten, Silver, Gold, Platinum, Rare Earths

• Energy Resources– Fossil Fuels: Coal, Oil,

Natural Gas – Uranium – Geothermal Energy

Types of Ore DepositsMagmatic• Pt, Cr, Fe, Ni, Ti, Diamond Pegmatite• Li, Be, U, Rare Earths,

Feldspar, Mica, Gems Hydrothermal• 600 C: W, Sn• 400 C: Au, U, Ag, Co, Mo• 200 C: Cu, Zn, Cd, Pb• Cool: Hg, As

Sedimentary Rocks• Fe, Cu, U, Mn, MgWeathering• Secondary Enrichment: – Cu, Ni

• Soils– Al, Ni

Placer• Pt, Au, Sn, Ti, W, Th, Rare

Earths U (Fossil), Gems

Concentration Factors and Economics

• Natural Abundance• Geologic Processes to Concentrate Element–Most involve water

• Intrinsic Value of Material• Cost of Extraction from Earth–Gold versus Gravel

Prospecting and ExplorationSatellite and Aerial

Photography Remote Sensing Geological MappingMagnetic Mapping Gravity Mapping Radioactivity Mapping

Geochemical Sampling Electrical Sounding Ground-

Penetrating RadarSeismic Methods – Reflection - Detailed

but Expensive – Refraction - Cheap but

Not Detailed Core Sampling and Well

Logging

Economic Factors in Mining

• Richness of Ore• Quantity of Ore• Cost of Initial Development• Equipment, Excavation, Purchase of Rights• Operating Costs: Wages, Taxes, Maintenance,

Utilities, Regulation• Price of the Product• Will Price Go up or down?

Life Cycle of a Mine• Exploration• Development• Active Mining– Excavation –Crushing, Milling, Flotation, Chemical

Separation – Smelting and Refining –Disposal of Waste (Tailings)

• Shut-down

Issues in Mineral ExploitationWho Owns (Or Should Own) Minerals?• Landowner, • Discoverer, • Government Unclaimed Areas: • Sea Floor, • AntarcticaWho Controls Access for Exploration?• Remote Sensing vs Privacy

Problems of MiningSafety• Mine Wastes• Pollution• Dust• Noise Sulfur (H2SO4)• Acid Rain• Acid Runoff• Dissolved Metals (Fe,

Cu, Zn, As...)

Environmental Problems

• Exploration• Construction and

OperationEconomic Impact• "Boom and Bust"

Cycles

Geothermal Energy: A Free Lunch?Environmental Problems

of Geothermal Energy• It is Finite • Heat Sources Can Be

Exhausted (Geysers, California)

• Sulfur Emissions• Disposal of Mineralized

Brines

Technical Problems of Geothermal Energy

• Corrosion• Mineral Deposition in

Pipes• Non-Productive gases

(Carbon dioxide, methane, etc.)

• Low Temperatures • Low Thermodynamic

Efficiency

Thermodynamic Efficiency

• Eff. = (Ti - Tf)/Ti

• T = Degrees Kelvin = Degrees C + 273• Ti = initial temperature• Tf = final temperature

Thermodynamic EfficiencyAutomobile Engine• Ti = 1200 C = 1473 K • Tf = 500 C = 773 K • Eff = (1473 - 773)/1473 = 48%

Typical Steam Power Plant• Ti = 700 C = 973 K • Tf = 200 C = 473 K • Eff = (973 - 473)/973 = 51%

Thermodynamic EfficiencyGeothermal Power Plant• Ti = 150 C = 423 K • Tf = 80 C = 353 • Eff = (423 - 353)/423 = 17%Actual achieved efficiencies• Automobile on Highway: about 5% • Geothermal Plant: 5% or So, Sometimes

less than 1%

Where the Oil Is

The Geography of Oil

Hubbert Curves

• In 1956, Oil geologist M. King Hubbert noted that rates of oil production follow a bell-shaped curve.

• Cumulative production follows a slanting S- curve• Production lags discovery by about ten years.

Hubbert’s 1956 Prediction

Where We Stand Today

What if We Find More Oil?• Even a huge

increase in total oil has very little effect on the peak and decline of production.

• Why? We waste most of it on inefficient uses.

One Solution: Limit Production

Is There a Lot More Undiscovered Oil?• 80 per cent of oil being produced today is from fields

discovered before 1973. • In the 1990's oil discoveries averaged about seven

billion barrels of oil a year, only one third of usage.• The discovery rate of multi-billion barrel fields has

been declining since the 1940's, that of giant (500-million barrel) fields since the 1960's.

• In 1938, fields with more than 10 million barrels made up 19% of all new discoveries, but by 1948 the proportion had dropped to only 3%.

Oil Discovery Rates

Some Relevant Quotes

The internal-combustion engine used for automobiles is a fragile device compared with other prime movers -- even compared with the internal combustion engines used for diesel- electric locomotives that have been known to go over a million miles without mechanical overhauling.

Some Relevant Quotes

... the energy-system efficiency of the motor car with petroleum motor fuel is, thus, 5 percent ... no one is proud of this accomplishment -- least of all the automotive-design engineers ... The trouble is, every time the design engineer manages to save a few BTU it is more than spent answering the clamor for softer tires, for radio, for better heaters, more lights, cigarette lighters and possibly even air conditioning.

Some Relevant Quotes

Histories written a few centuries hence may describe the United States as a nation of such extraordinary technologic virility that we succeeded in finding ways of dissipating our natural wealth far more rapidly than any other nation. At any rate, we are having a wonderful time doing it. From the discussions in the earlier chapters of this book it is clear that the problem of energy for the United States is not one of the dim future. It is upon us now.

Some Relevant Quotes

Our imports of petroleum are small but each year they become larger. By 1960 they are likely to be quite substantial. By 1970 they will almost certainly be huge -- if foreign oil is still available then in sufficient quantity... This tiny period of earth's life, when we are consuming its stored riches, is nearly over ... Fortunately for us there is still time for fundamental research [on alternative energy sources]. But not too much time.

Some Relevant Quotes: Source

Eugene Ayres and Charles A Scarlott, 1952; Energy Sources -- The Wealth of the World, McGraw-Hill, 344p.

Petroleum is a Syllogism

• There is a finite amount of it in the world• We are using it and not replacing it• Therefore we will eventually run

out of it• Any of this not clear?

The End of Cheap Oil• Known petroleum can last at least a couple of

centuries more, but…• It only flows through the rocks so fast.• No amount of drilling will make it flow faster,

and careless drilling can shorten the lifetime of an oil field.

• Sometime in the 21st century, global demand will outpace production capacity and…

• Oil will go to the highest bidder.

Some Final ThoughtsWhat have you personally done to deserve access to

petroleum at any price?If you think energy is such a scam, get up off your butt

and do something about it. • If you think there is undiscovered oil out there, study

geology and engineering and find it!• If you think synthetic oil is the answer, major in chemistry

and make it happen.• If you think the answer is alternative energy sources, major

in physics and engineering and develop them. • Don’t major in Plain Vanilla Studies and then complain when

other people don’t provide you with energy for free.