The energy minerals are minerals, metals, rocks and hydrocarbons (solid and liquid) extracted from the ground and used in a wide range of industries related to construction, manufacturing, agriculture and energy supply.
Energy minerals are used to produce electricity, fuel for transportation, heating for homes and offices or for the manufacture of plastics. Energy minerals include coal, oil, natural gas, and uranium.
Almost all materials on Earth are used by humans for something. We require metals to make machines, gravel to make roads and buildings, sand to make computer chips, limestone and plaster to make concrete, or clay to make pottery.
In turn, we use gold, silver, copper and aluminum to make electrical circuits and diamonds, and corundum (sapphire, ruby, emerald) for abrasives and jewelry.
Mineral resources can be divided into two main categories: metallic and non-metallic.
Metallic resources are elements such as gold, silver, tin, copper, lead, zinc, iron, nickel, chromium, and aluminum. Non-metallic resources are materials or elements such as sand, gravel, gypsum, halite, uranium, or dimension stone.
Characteristics of energy minerals
An energy mineral or mineral resource is a rock enriched with one or more useful materials. Finding and exploiting mineral resources requires the application of the principles of geology.
Some minerals are used as they are in the soil, meaning they require little or no additional processing. For example, gemstones, sand, gravel, or salt (halite).
However, most mineral resources must be processed before being used. For example: iron is found in abundance in ores, but the process of extracting iron from different ores varies in cost depending on the ore.
It is less expensive to extract iron from oxide minerals such as hematite (Fe2O3), magnetite (Fe3O4), or limonite.
Although iron is also produced in olivines, pyroxenes, amphiboles, and biotite, the concentration of iron in these minerals is lower, and the cost of extraction is increased because the strong bonds between iron, silicon, and oxygen must be broken.
Aluminum is the third most abundant mineral in the earth's crust. It occurs in the most common mineral resources of the crust, therefore they are generally the most sought after. Which explains why recycling aluminum cans is profitable, as the aluminum in the cans does not have to be separated from oxygen or silicon.
Because extraction costs, labor costs, and energy costs vary over time and from country to country, what constitutes an economically viable mineral deposit varies considerably in time and place. In general, the higher the concentration of the substance, the cheaper the mine.
Therefore, an energy mineral is a body of material from which one or more valuable substances can be economically extracted. A mineral deposit will consist of minerals that contain this valuable substance.
Different mineral resources require different concentrations to be profitable. However, the concentration that can be economically extracted changes due to economic conditions such as demand for the substance and the cost of extraction.
For example: the concentration of copper in the deposits has shown changes throughout history. From 1880 to 1960 the copper ore grade showed a steady decline from about 3% to less than 1%, mainly due to increased mining efficiency.
Between 1960 and 1980 this value increased to more than 1% due to rising energy costs and an abundant supply produced by cheaper labor in other countries.
Gold prices vary on a daily basis. When gold prices are high, the old abandoned mines reopen and when the price falls, the gold mines close.
In first world countries, the cost of labor is currently so high that few gold mines can operate profitably, a situation totally contrary to third world countries, where gold mines have mineral concentrations much lower than those found in first world countries.
For each substance we can determine the concentration needed in a mineral deposit for profitable mining.
By dividing this economic concentration by the average abundance of the crust for that substance, we can determine a value called the concentration factor.
Examples and abundance of energy minerals
Below is the average energy mineral abundance and concentration factors for some of the commonly sought mineral resources.
For example, aluminum has an average abundance in the earth's crust of 8% and has a concentration factor of 3 to 4.
This means that an economical deposit of aluminum must contain between 3 and 4 times the abundance of the average earth's crust, that is, between 24 and 32% aluminum, to be economical.
- Aluminum; 8% from 3 to 4
- Iron; 5.8% from 6 to 7
- Titanium; 0.86% from 25 to 100
- Chrome; 0.0096% from 4000 to 5000
- Zinc; 0.0082% of 300
- Copper; 0.0058% from 100 to 200
- Silver; 0.000008% of more than 1000
- Platinum; 0.0000005% of 600
- Gold; 0.0000002% from 4000 to 5000
- Uranium; 0.00016% from 500 to 1000
References
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