Mineral Resources
- Dec 15, 2015
- 3 min read
The greatest practical value of geology lies in locating, mapping, and exploiting the economic resources of Earth. These resources include not only the deposits of copper, lead, mercury, gold, coal, and oil that first come to mind, but also building stone, cement rock, ceramic clays, glass sands, and many other nonmetallic materials that are not as “glamorous” as the metallics or the fuels, but are often of equal if not greater real value to a nation’s economy. This section deals with the means of locating economic deposits, and a discussion of their occurrence and their relation to the geologic phenomena we have studied before. This is where you’ll fully appreciate the important relation of geology to humans.
We’re currently facing a critical problem. The human population is rapidly increasing, yet there is only a finite amount of metal ores and fossil fuels near the surface of Earth. It has been estimated that there were only 100,000 humans in the world 1.6 million years ago—when the genus Homo evolved fromAustralopithecus. Around 10,000 years ago, at the end of the last glaciation, there were approximately 2 million people in the world (less than the population of the Twin Cities metropolitan area). Extensive metal mining and agriculture began at that time. The video below shows what has happened in the past 2,000 years. Over half of all the people who have ever lived on Earth are alive right now! Further, human population growth shows no signs of significantly slowing. Unchecked, the world’s population coulddouble every 25 years!
The ratio of the total volume of metal ore to the surrounding rock in a mining district is about 1 percent or less, and the ratio of surface area of mining districts to the area of the continents is also less than 1 percent. We have used as much metal ore since 1930 as in all of previous human history! As a result of the population explosion, the rate at which we are using mineral resources is increasing dramatically. The first extensive use of fossil fuels began about 1800 with the development of the steam engine. At the present rate of use, all the oil in the world could be used up by 2050 and the coal reserves by 2300. Between 1900 and 1980 alone, we used half of Earth’s known oil.
The only way we are able to support the present high population of the world is to use the energy from fossil fuels to produce and distribute food and goods. One downside of this is the greenhouse effect, the climatic warming that has already begun and may result in a large shift of climate belts, animal and plant extinctions, and the melting of glaciers and possibly an ultimate sea level rise of 300 feet. That would mean we could say goodbye to New Orleans, Florida, Washington, D.C., and other places. This warming is due largely to the carbon dioxide (CO2) produced by burning fossil fuels and wood. The amount of CO2 in the atmosphere has doubled since 1800.
Alternative sources of energy such as solar, hydro, and wind power need to be developed, but they do not produce enough power to support the present number of people, let alone the number to come. Nuclear energy has a bad press, but is (believe it or not) safer than coal-fired power plants, which emit more radioactivity and far more pollution than any non-Russian nuclear power plant. The ultimate energy source is fusion nuclear power, which produces no wastes except for useful helium. The fuel is heavy hydrogen, which is relatively easy to extract from seawater and is abundant enough to last for several million years. But fusion is not yet a commercial power source.
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