Mineral and Energy Resources: Types, Extraction, and Sustainable Management
Mineral and Energy Resources of the Geosphere
The resources of the geosphere can be divided into mineral and energy resources. Among the latter, we will study fossil fuels, nuclear energy, and geothermal energy.
Mineral Resources
Mineral resources constitute a vital resource to sustain industrial activity. Given their non-renewable nature, there is a constant search for new sources as those that have been exploited are depleted.
Types of Deposits
- Deposits of foreign origin are found in sedimentary rocks, gravel pits and rivers, gold nuggets, oxides, limestone, clay, salt deposits, and sites that result from the disturbance of soils, such as bauxite and kaolin.
- Deposits of domestic origin are formed by endogenous activity found in terrestrial, metamorphic, and magmatic rocks. The best deposits are found in veins and reefs.
Types of Mineral Resources
- Non-metallic mineral resources: sulfur, salt evaporites, or minerals such as salt and gypsum, used in construction, and phosphates used as fertilizers.
- Metallic mineral resources: resources from which metals are obtained that are used in industry, such as iron, aluminum, copper, lead, etc., in medicine and other technological applications, such as mercury, silver, and tin.
- Industrial and quarry resources: many rocks and minerals used in construction, such as ornamental stone, limestone, clay, and loam for the manufacture of cement, clay for ceramic and refractory material, gravel, and sand as aggregate for construction and paving, and sand to make glass.
Energy Resources
Fossil Fuels
As discussed in the first unit, fossil fuels were first used during the Industrial Revolution.
Coal
Coal deposits were formed by the deposition and burial of plant remains in swamps and bogs during the Carboniferous, Triassic, and Jurassic periods, and subsequent anaerobic fermentation in an environment saturated with water. Moreover, in this transformation, the temperature and compaction suffered because of the burial also affected the process. The primary use of coal is to generate electricity in power plants or for heating.
Drawbacks: Apart from the impact caused by mining and quarrying activities, coal combustion produces carbon dioxide and sulfur dioxide, which contribute to the problem of greenhouse gases and acid rain.
Oil
Oil is the main energy resource today. It is formed by an accumulation of organic matter from phytoplankton and zooplankton in marine sedimentary basins with anaerobic conditions. Extraction can be done on both continents, through oil wells, and in the oceans, through offshore platforms. Transport is by pipelines or tankers. Before its use, it must be subjected to fractional distillation wherein, as the temperature rises, the various components are separated and collected.
Natural Gas
Natural gas is formed along with oil and is found above it in available sites since it has much less density. Therefore, it is also extracted through wells or platforms, but its removal is easier than oil. It is a mixture of gases (methane, hydrogen, ethane, propane, butane) and is transported mainly by pipeline. It is used either to produce electricity in power stations or for heating. It has a higher calorific value than coal and oil.
Fission Nuclear Energy
Fission nuclear energy is the energy released in fission reactions of fissile nuclei of elements such as uranium-235 or plutonium. When a neutron is absorbed by a uranium nucleus, it becomes unstable and decays into lighter nuclei, neutrons, and energy. The neutrons interact with new kernels of uranium, producing a chain reaction. The energy released is a result of some mass being converted into energy quanta and is used for electricity production.
Geothermal Energy
Geothermal energy is the heat inside the Earth’s surface that occurs in certain areas of the world as hot springs or steam. It is considered a perennial power, and therefore renewable, since the production of heat by the Earth’s core far exceeds the existence of the human species on the planet.
Impacts and Risks of Mining Activities
Mining requires environmental impact studies that should evaluate the impact of mining on water quality, noise and vibration, the volume of tailings, as well as their location and stability, the risks of subsidence and its prevention, etc.
Underground mining is carried out using two types of mining, each with different impacts and risks:
- Open-pit mining is used when the deposits are shallow. Quarries can also be included here.
- Underground mining involves the excavation of the land through shafts and tunnels to reach the site, which is deeper than in the previous case.
Impacts and Risks Resulting from Consumption
Impacts and risks are due to pollution caused by burning oil and coal in the atmosphere, as we have seen: the greenhouse effect, acid rain, and deterioration of the ozone layer. Natural gas is a cleaner fossil fuel, not having sulfur. We have also studied how radioactive elements and heavy metals are introduced and concentrated in food chains, killing living beings and posing a potential risk to human populations.
Traditional Resource Management
Traditional resource management in geology is based on meeting the demands of continued growth. The industrial growth loop is a continuous expenditure of fossil fuels and exploitation of rocks and minerals for the production of metals and other materials. It is, therefore, a supply-based management, so that these resources must be kept at a reasonable price. Often, underdeveloped or developing countries are the holders of these resources, so rich countries impose economic criteria to obtain cheaper resources.
Sustainable Resource Management
Since the rate of renewability far exceeds the period of our species on the planet, these resources are considered non-renewable. However, within them, we have to distinguish between energy resources, whose use is also consumptive, and mineral resources, whose use is consumptive but can be reused. Therefore, we use the principle of sustainable drainage but with two different shades. Also, taking into account the principle of sustainable selection of technologies, scientific and technological research should aim at achieving higher rates of energy efficiency in all processes involved, from the extraction and obtaining of the resources to transport, use, and treatment of the residues.
Concrete measures to implement these principles should be:
- Demand management that combines the progressive raising of prices in terms of increased consumption and the training and education of citizens to avoid waste. This could reduce consumption of these resources.
- The promotion and organization of reuse and recycling technologies through networking of waste collection and financial support to enterprises engaged in it.
- The gradual replacement of non-renewable energy with renewable energies through EU aid, state, and government of the autonomous communities.
- The promotion of research in the development of efficient technologies and their implementation through financial assistance from these bodies.
Waste Management
The use of fossil fuels inevitably involves the production of waste gases, which pollute the atmosphere and cause environmental problems already known. Here we refer to the solid waste that is dumped in different parts of the geosphere. Although these residues have a different nature, they all lack the dispersed nature possessed by gaseous and liquid waste, so they can be concentrated with relative ease, even if it is at a negligible energy cost. Consider the daily collection of millions of tons of waste generated by modern societies. Depending on its rate of degradation or weathering, the principle of sustainable emission may or may not be applied. But this principle can be complemented by the resources used, as many of these wastes can be converted back into resources after being subjected to a series of processes for reuse and/or recycling.
Regarding nuclear waste, it is noteworthy that some of them, such as plutonium, remain radioactive for thousands of years (up to 10,000), which constitutes a risk to human populations. They are temporarily stored in cans in pools of nuclear power plants. For final disposal, stable subsurface areas in the ocean and continents are considered. Continental nuclear cemeteries are situated at great depth (between 300-1000 meters) in a very stable structure so that security surveillance is not needed in the future. There is currently no definitive solution to neutralize it (it has even been considered to send them out of the Earth by rockets), and the generation of nuclear waste is the main cause, along with the risk of accidents, that critics argue against this type of energy.