LWU: Lesson - Impacts of Mining (Topic 5.9) 📖
⏳ Estimated Reading Time: 9 - 11 minutes
Describe natural resource extraction through mining and the ecological and economic impacts of mining.
Mining
Ores are rocks that contain valuable minerals, such as metals, that can be extracted and used for various purposes. However, not all ores have the same quality or concentration of minerals. Some ores are more accessible, meaning they are easier to find and reach, and some have higher grades, meaning they have more minerals per unit of rock. Easily accessible high-grade ores are more desirable and profitable for mining because they require less effort and resources to process and refine.
However, as high-grade accessible ores are mined to depletion, mining operations are forced to access lower grade ores. Accessing these ores requires increased use of resources, such as energy, water, chemicals, and machinery, that can cause increased waste and pollution, which can harm the environment and human health, by contaminating the soil, water, and air, and affecting the biodiversity and ecosystem services of the mining areas.
As the more accessible ores are mined to depletion, mining operations are forced to access lower grade ores. Accessing these ores requires increased use of resources that can cause increased waste and pollution.
Surface Mining
There are two main methods of surface mining: mountaintop removal and strip mining.
Mountaintop Removal
Explosives are used to break up the rock and heavy machinery to carry the coal away in mountaintop removal. This method has been used frequently in the Appalachian Mountains. Debris from this type of mining is put in the valleys and the mountains are left exposed.
Strip Mining
In strip mining, after the coal has been removed, huge open pits are left behind. These pits are filled with overburden, or unneeded rock and soil, from adjoining strip mines.
Surface mining is the removal of large portions of soil and rock, called overburden, in order to access the ore underneath. An example is strip mining, which removes the vegetation from an area, making the area more susceptible to erosion.
Subsurface Mining
Subsurface mines are underground mines used to retrieve deep coal deposits.
These mines can either consist of small “rooms” or large open areas. Although subsurface mining does less damage to the surface of the earth, they have proven to be much more dangerous to humans working in them.
There are two main types of subsurface mining: room and pillar and longwall mining.
Room and Pillar
Room and pillar mining involves creating a network of rooms and pillars in the mined area, leaving some coal or ore in place to support the roof. The rooms are the spaces where the coal or ore is extracted, and the pillars are the columns of coal or ore that are left behind. This method reduces the risk of sinkholes but also leaves behind some of the deposit.
Longwall
Longwall mining involves using a large cutting machine that moves along a long face of coal or ore, shearing it off and letting it fall onto a conveyor belt. The roof behind the machine is supported by hydraulic jacks that are gradually moved forward as the face advances. This method allows for higher recovery and productivity but also causes more sinkholes and environmental impacts.
As coal reserves get smaller, due to a lack of easily accessible reserves, it becomes necessary to access coal through subsurface mining, which is very expensive.
Economic Impacts
Mining is an important industry that contributes to the economic development and growth of many countries.
Economic Impacts of Mining:
✅ provides jobs and income for communities
✅ stimulates manufacturing, transportation sectors of the economy
✅ provides low-cost energy
❌ depletes natural resources, which can reduce long-term economic potential of the area
❌ environmental degradation and pollution, which can harm human health and reduce tourism
Mining helps provide low-cost energy and materials necessary to make products.
Ecological Impacts
Mining impacts the environment in a variety of ways.
The environmental impacts from the various methods of mining can be significant. Various government organizations in the United States have created a number of laws and regulations to attempt to mitigate that damage. Progress has been made but as long as there is a need for minerals and other mined materials, impacts to the environment will continue.
Different types of mining come with different types of environmental impacts.
Surface Mining
Surface mining tends to have a higher environmental impact than underground mining because the habitat on the surface is destroyed during the mining process. Below are some other environmental impacts of surface mining:
❌ habitat loss and fragmentation
❌ reduced biodiversity
❌ waste can runoff into surface waters or infiltrate groundwater, reducing water quality, affecting the availability of fresh water for drinking, and harming aquatic life
❌ release of dust and greenhouse gases
❌ increased erosion due to removal of topsoil and vegetation
Subsurface Mining
Subsurface mines do not have as much of an effect on the surface because most of the activity is underground. his means there is less habitat disruption and biodiversity loss. However, subsurface mines still have an impact on the environment. Below are some environmental impacts of subsurface mining:
❌ release of dust and greenhouse gases
❌ waste can infiltrate groundwater, affecting the availability of fresh water for drinking
❌ mine tunnels can collapse causing sinkholes
❌ mines can also catch on fire and burn for many years.
Centralia, Pennsylvania is a near-ghost town that has been burning since 1962 due to a coal mine fire. The fire has caused most of the residents to leave the town, and the state has claimed all the property under eminent domain.
The mining of coal can destroy habitats, contaminate groundwater, and release dust particles and methane.
Mining impacts are not limited to the damage done directly to the land. Energy is used (usually in the form of fossil fuels) to extract, haul, and process the material that is mined. This creates air pollution and can result in water pollution.
Additionally, the processing of mining material results in significant quantities of waste that must be dealt with carefully to avoid contaminating surrounding areas. Soil and rocks that are moved to gain access to the ore are called overburden. This rock is removed and stored or disposed of before the ore can be mined.
Slag and tailings that remain when the minerals have been removed from the ore are also called spent ore or mill tailings, and they are the residues that are left after the ore is crushed, ground, and separated from the valuable minerals. They usually contain some traces of the minerals, as well as other substances, such as water, chemicals, and metals.
All this waste that must be dealt with carefully to avoid contaminating surrounding areas.
Mining wastes include the soil and rocks that are moved to gain access to the ore and the waste, called slag and tailings that remain when the minerals have been removed from the ore.
Legal Solutions
Because mining has so many potential environmental impacts associated with it, several laws have been passed to address the impacts. Some of these laws are federal laws passed at the national level and some laws are state laws. States can pass environmental laws that are stricter than federal laws, but they cannot pass laws that are less strict than a similar law at the federal level.
The passage of the following federal laws has resulted in cleaner environmental conditions in and around mining sites:
Choose one accordion tab that interests you the most and open it. Open another accordion tab that you have not explored yet. Compare and contrast it with the previous one. Finish by checking the other tabs you have not yet explored:
Clean Water Act (CWA) 💧 (click to reveal)
The Clean Water Act (CWA) aims to restore and maintain the quality of surface waters. The CWA requires permits for direct or indirect discharges of pollutants to surface waters and sets standards for water quality and effluent limitations. The CWA also regulates the disposal of dredge-and-fill materials into surface waters, including wetlands.
EXAMPLE VIOLATION:
On August 5, 2015, a release of about three million gallons of water and sediment occurred at the Gold King Mine near Silverton, Colorado. At the time of the release, the U.S. Environmental Protection Agency (EPA) was conducting an investigation of the Gold King Mine to assess the ongoing water releases from the mine, to treat mine water, and to assess the feasibility of further mine remediation. During exploratory excavation of the mine portal, pressurized water began leaking from the mine tunnel, releasing water and sediment into Cement Creek, a tributary of the Animas River. The leak worsened and eventually allowed all of the mine drainage to escape. Once the mining waste entered the surface waterway, it made its way downstream impacting all of the aquatic species in the river.
Safe Drinking Water Act (SWDA)🚰 (click to reveal)
The Safe Drinking Water Act (SWDA) protects the quality and safety of drinking water sources. The SWDA sets standards for the treatment and monitoring of public water systems and regulates the underground injection of fluids that may contaminate drinking water aquifers. It also establishes programs to protect groundwater and source water from contamination. If the water supply exceeds maximum containment levels, the water supply must be closed.
EXAMPLE VIOLATION:
In the case of the Gold King Mine release described above, much testing was done in the Animas River watershed to ensure the protection of anyone who used that water for their drinking water. Additional considerations included the health of fish species in the river as well as the impacts on livestock and larger animals that used the water for their drinking water.
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) 🛢️ (click to reveal)
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund, authorizes the cleanup of hazardous waste sites that pose a threat to human health or the environment. It also establishes liability for the parties responsible for the contamination and provides funding for the cleanup and restoration of contaminated sites. CERCLA applies to mining sites that release or threaten to release hazardous substances, such as metals, acids, or toxic chemicals, and requires that hazardous substances be reported if they are released.
If the violating company does not report the hazardous waste release to the federal government in a timely manner, they are liable for any damages that occur, and fines can run into the millions of dollars. If they DO report the release, they may still have to pay for the cleanup of the release but will not be fined by the government. So, it is cheaper for a company to self-report to stay within the boundaries of this law.
EXAMPLE VIOLATION:
In the case of United States v. Tyson Foods, Inc., which was settled in 2019, Tyson Foods, a poultry producer, agreed to pay $2 million in civil penalties and $500,000 in natural resource damages for releasing hazardous substances from its facilities in Missouri, Tennessee, and Kansas. The hazardous substances included ammonia, nitrate, and phosphorus, which contaminated surface water and groundwater, and harmed fish and wildlife. Tyson Foods also agreed to implement measures to prevent and reduce future releases and to restore the affected natural resources.
There are accidents but, for the most part, the biosphere is a better place because of stricter controls on mining. Of course, this comes with a cost to consumers because mining companies pass along the expense associated with complying with the laws to the consumer in the form of higher prices for mined materials.
Economic impacts always relate back to money somehow.
Ecological impacts always relate back to the environment.
There are 10 federal laws that you need to know for the AP exam. CWA, SWDA, and CERCLA are 3 of these 10 laws.
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