Mineral Resources

  

Welcome to Poorna's Pages at the Glendale Community College. Here we discuss the geological or extractive earth resources. Note that these resources are largely nonrenewable or exhaustible to potentially renewable and broadly comprise water and soil, minerals and energy resources. Water (surface and underground) and soil have been examined elsewhere, mineral resources are being examined here, and energy resources are discussed elsewhere in this module.

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Updated on 05-05-15
 

Contents of the
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Other topics in this Module:

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Glaciers and glaciation
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Waves, beaches and the coasts
bullet

Energy resources
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The earth hazards
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Nature and dimensions of environmental crisis
 

On this page ...

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Nature of Earth Resources
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Mineral deposits
Types (metallic minerals, nonmetallic and industrial minerals)
Occurrences
Issues of exhaustibility and environmental degradation

   
   
   
   
   

Nature of Earth Resources:
 

Earth resources range from the extractive ones like mineral and most of the energy resources that are largely nonrenewable or exhaustible to potentially renewable resources like air, water and soil and the supposedly perennial or renewable resources like solar, wind, water, waves, tides, oceans (i.e., the solar heat trapped in warm surface waters of the tropics).
 
Two of the typically extractable ones of these, discussed here, are broadly grouped as:
 
bullet mineral resources:
bullet metallic
bullet nonmetallic and
bullet industrial), and
bullet energy resources:
bullet fossil fuels
(Coal, Oil and Natural Gas)
bullet nuclear energy, and
bullet alternate/futuristic energy resources.


Before discussing these resources, though, we need to understand two extra-geological constraints that define our efforts:
 
bullet the "McKelvey Box" approach that distinguishes what is available from what can become available, based on technological feasibility and cost-effectiveness; and
bullet the well-known "supply-demand" equilibrium of classical economics that drives technological feasibility and innovation.

 

Of these, the "McKelvey Box" approach is schematically explained in the figure on the left and concerns the definition of reserves and what distinguishes reserves from resources. Reserves are what we have  discovered already and can economically extract whereas resources encompass a much broader spectrum. We have certainly had a great deal more of oil in Shakespeare's time than what now remains, for instance, but "oil" was not a resource in his time.

 

If this constraint is part technological and part economic, the second constraint is even more directly economic and is explained in illustration below.

 

  

Suppose at a given point in time, the demand for a resource is defined by D1 and its supply by S1. The demand schedule here slopes downwards, of course, suggesting that the lower the price the greater will be the quantity consumed. Likewise, the supply schedule slopes upwards here, reflecting the fact that the steeper the price the greater will be the incentive to produce and that increases the supply. Price (P1) and quantity (Q1) are then defined by the point at which these two schedules intersect. What if the demand suddenly shoots up, say to the new demand schedule D2? If the supply schedule concomitantly rises to S2 then the new equilibrium price will be P2 and quantity Q2.
 

On the other hand, if the supply schedule stays the same ― the likely scenario for exhaustible resources, then the new equilibrium price will be P3 at the quantity Q3. Note that Q3 is less than Q2 but P3 is greater than P2. What if there is a glut in the market, with demand D2 reverting back to D1? The price will now fall to P4 if supply S2 does not change but may revert to P1 if S2 reverts to S1. As we shall see later on this page as also elsewhere, inflation-adjusted long-run prices of the earth resources have hardly increased as rapidly as their demand.


Read these USGS Open File Reports to learn about the factors that shape mineral supply and demand:
 

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Open File Report 02-418: "Policy – A Factor Shaping Minerals Supply and Demand" (by Thomas Goonan).
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Open File Report 02-418: "Sociocultural and Institutional Drivers and Constraints to Mineral Supply" (by William Brown).

 

Mineral Deposits:

Click on the right for
historical statistics for mineral and material commodities
 in the United States

 

or click on the left for the USGS mineral resources pages
 Types of mineral resources:
 
bullet Metallic minerals


The metallic mineral include
 

bullet

ferrous metals (ores of iron, manganese, chromite, nickel, cobalt etc.),
bullet

non-ferrous metals or polymetallic deposits (ores of copper, lead, zinc, tin, tungsten etc.) and

bullet

precious metals (e.g., gold, silver, platinum)


Their suitability for mining is defined by the concentration factor. This factor is basically defined as

and ranges from about 60 ppm (parts per million) for copper, 2 ppm for tin, 4 ppb (parts per billion) for gold etc., i.e., the more scarce a resource is the smaller its concentration needs to be for its cost-effective extraction.
bullet Nonmetallic and industrial minerals:

These include such industrial minerals and materials like barite, gypsum, halite etc., and gemstones as diamond, ruby, sapphire, amethyst etc.

The average per capita consumption of selected
 mineral resources in the U.S., based on 2000 data

 

Occurrences of mineral
deposits:

 

 

bullet Deposits in igneous and metamorphic rocks:
 

Metallic deposits like those of chromium, platinum and iron often occur in crystal setting within cooling magma.

 
Polymetallic deposits of copper, lead, zinc, gold, silver, nickel, cobalt, tin, tungsten, molybdenum, mercury and iron occur as hydrothermal deposits (contact metamorphism, hydrothermal veins, disseminated deposits and hot-spring deposits).
Pegmatites often carry lithium, mica, rare metals and barites.

Polymetallic deposits often occur in the folded mountain belts. Notice how porphyry copper and molybdenum deposits dot the entire subduction zone from Andes to the Cascades. Almost all the U.S. reserves of gold, silver, platinum and palladium come from the western U.S., from Rockies to the Sierras and Cascades.

bullet

Other types of ore deposits:

These include the chemical precipitation in layers, in the case of most of iron and manganese and some copper deposits, placer deposits of gold, tin, platinum and titanium, and concentration by weathering and groundwater (e.g., of diamond brought to the surface from kimberlite pipes; forming of bauxite and laterite by chemical weathering), and the supergene enrichment of disseminated ores.

Issues of exhaustibility and environmental degradation:
 

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The nature of the problem:

Two problem are ubiquitous with mineral and similar earth resources ― their likely exhaustibility and the environmental impact of their use. As for the first of these, since our need for these resources has only been rising, their prices too should rise  because, with increasing use, their supply is only likely to decline. The exhaustibility of these extractive earth resources thus remains a problem irrespective of whether we take

 
bullet the Malthusian perspective, that exhaustibility limits socioeconomic growth;
bullet the neo-Malthusian perspective, that resource exploitation has environmental limits, or
bullet the Ricardian perspective, that progressive depletion raises costs and lowers quality.

On the other hand, no such threat of imminent exhaustibility exists if we take the cornucopian view, that technological innovation will always provide substitutes and alternatives. The question is if such has indeed been the case.
 
bullet

The actual price situation:

Interestingly, as can be seen in the graph below, where we compare the long-run inflation adjusted prices of four of the most used nonferrous metals ―  aluminum, copper, tin and zinc, these prices have mostly stayed steady about their 1978 levels.

 

 

Actually, the U.S. as well as world-wide demands for the mineral resources has only continued to rise. This is clearly seen in the two graphs on the right where the top one shows the U.S. consumption of minerals and other materials and bottom graph shows the world's per capita aluminum consumption.

What inferences are we to draw from this, other than simply ascribing it to a combination of technological advances, economy of scale and efficient use?

Click on the World-watch Institute logo below to learn about the environmental costs of increased mining activity.