Surface mining is a type of mining in which the soil and rock that are on top of the mineral deposit are removed.
In contrast to underground mining, where the overlying rock is left in place and the mineral is extracted through shafts, surface mining, which includes strip mining, open-pit mining, and mountaintop removal mining, removes the soil and rock that are on top of the mineral deposit (the overburden).
This technique was first applied in the middle of the 16th century in North America, where the majority of surface coal mining takes place and is being employed today in the mining of many different minerals.
Throughout the 20th century, surface mining gained prominence, and now, the majority of the coal mined in the United States is produced through surface mines.
In the majority of surface mining techniques, the overburden is first removed using large machinery like earth movers.
The mineral is then extracted using big machineries like drag line excavators or bucket-wheel excavators.
The term “Strip Mining” refers to one of the various methods of surface mining.
The unavoidable truth is that the environmental impacts of strip mining are being overlooked by many countries due to the fact that mining brings a lot of cash but this is at the expense of the environment and our health.
What is Strip Mining?
Stripping, often known as strip mining, is the removal of trash or overburden from open-pit surface mines.
Machines like stripping scoops, basin wheel excavators, or draglines are used in the process to remove the stone and expose the valuable metal that is being mined.
Reaching coal that is buried close to the surface, requires scraping away dirt and rocks. Mountains are frequently destroyed to access the interior’s shallow coal seams, leaving behind enduring scars on the landscape.
Around 40% of the world’s coal mines use strip mining, however in some nations, like Australia, open-cast miners account for the majority of mines.
Industry frequently favors strip mining even though it is very harmful since it uses fewer workers and produces more coal than underground mining.
In strip mining, an overburden—a thin layer of material—is removed to gain access to the minerals buried below.
Since it is more practical, simpler, and quicker to remove the overburden to access the minerals, this type of mining is especially helpful when the minerals are situated fairly near the surface.
Usually, coal and tar sand are mined by strip mining. The technique is also known as open cast, open cut, or stripping.
First, heavy-duty bulldozers are used to clear the area to be mined of all trees, plants, and other structures.
Then, holes are dug to deposit explosives that will loosen the overburden so that earth-moving machinery may remove it with ease.
Minerals are extracted after they have been made visible. There are two main forms of strip mining. which include:
- Area Mining
- Contour Mining
1. Area Mining
Area mining is the method that is most frequently used in the Midwest and Western United States’ flat or lightly rolling countryside.
Area mines create enormous rectangular pits that can be several hundred yards wide and more than a mile long. These pits are farmed in a series of parallel strips or cuts.
Area mining starts with a preliminary rectangular cut after plants and the top layer of soil have been removed (called the box cut).
The operator removes the box cut spoil from the area where mining will proceed by placing it on one side.
Large stripping shovels or draglines are used in large open pit mines to remove the overburden.
The operator then creates a second, parallel cut after removing the coal from the initial cut.
The operator grades and compresses the spoil before placing the overburden from the second cut into the ditch created by the first cut.
The back-filled pit is then seeded and covered in topsoil.
As long as the stripping ratio—the ratio between the overburden and the coal seam—makes it feasible to collect coal economically, this procedure is continued along parallel strips of land.
They’re doing it for financial gain!
For instance, as the coal seam gets thinner or when it dives farther below the surface, mining may end there.
When the operator reaches the final cut, the overburden from the initial or box cutter is the only spoil left to fill this cut.
The operator typically finds it more cost-effective to forgo towing the box cut spoil to the last cut because it may be some distance away.
He might decide to make a stable water impoundment in the final cut as an option.
Although common in the coal regions of the Midwest, these last-cut lakes can cause problems with the environment and land use.
2. Contour Mining
The Appalachian region of North America, where coal seams protrude from the sides of hills or mountains, is essentially the only place where the contour approach is applied.
Cuttings are made on the slope or angle where the coal seam is located during contour mining, first removing the overburden and subsequently the coal itself.
Similar to area mining, overburden from later cuttings are utilized to fill earlier cuts. The operator continues to make cuts until the dirt to coal ratio is unprofitable.
The process continues along the mountain’s contour up until the operator’s or the coal resources’ exhaustion.
Small earth-moving machinery, such as bulldozers, backhoes, and power shovels, is required for contour mining, just like it is for standard building projects.
Thus, small, frequently undercapitalized operators in Appalachia choose to mine in this way.
For instance, workers in the construction sector can readily transition in and out of the mining industry as market conditions change.
After the excavation is finished, contour operators frequently have too much spoil. The “swell factor” is to blame for this.
When overburden is removed, it disperses and loses some of the compactness that it developed by being undisturbed and intact for thousands of years.
The volume of the material increases by up to 25% even after replenishment and mechanical compaction.
The pits that are left over after the relatively thin coal seams of the East are removed are typically too small to accommodate this extra volume.
As a result, the majority of contour miners must dispose of their excess spoil in another “valley fill” or disposal area.
The head of hollow fills or valley fills, also known as disposal zones, are located at the valley bottoms.
For full development, additional land that is not required for mining must be disturbed.
Places Where Strip Mining has been Practiced.
Only when the ore body needs to be dug up is it feasible to use strip mining.
Some of the largest equipment on the planet, such as bucket-wheel excavators capable of digging up to 12,000 cubic meters of dirt per hour, are needed for this type of mining.
Even though the majority of surface coal mining occurs in North America, it started in the middle of the 16th century and is being used today all over the world.
However, in some places strip mining has been practiced including:
- United States of America
1. The United States of America.
The largest coal reserves in the world, which the United States is known to possess, were made feasible through continuous mining.
The Appalachian Mountains and surrounding regions, the Central Plains from Indiana and Illinois through Oklahoma, and new mines for sub-bituminous coal in North Dakota, Wyoming, and Montana are the principal places where strip mining has taken place.
On Hopi and Navajo territory, significant mining is also done, particularly in Black Mesa in northeastern Arizona, West Virginia, Kentucky, and Pennsylvania.
Five key locations in Russia, where strip mining is prevalent, leading to the country’s five largest coal mines.
Rostov Oblast, Komi Republic, Krasnoyarsk Krai, Sakhalin Oblast, and Sakha (Yakutia) Republic are among the places mentioned.
The Northern Shaanxi Mine is situated in Shaanxi, Inner Mongolia, in China (Heidaigou mine).
Chhattisgarh and Odisha are two regions in India where strip mining has been practiced.
East Kalimantan and South Kalimantan both had strip mining.
West Germany is home to numerous large-scale strip mining operations, particularly close to Cologne and Aachen (the pit at Hambach is presently recognized as the largest and deepest in Europe).
Pits of a smaller size can be discovered close to Hotensleben.
Belchatow, lower Silesia, and Bogatynia
Environmental Impacts of Strip Mining
Like other actions man has been involved in that cause destruction to the earth, strip mining impacts negatively on the environment.
Any of these mining methods will drastically impact the environment if necessary safeguards aren’t performed.
Appalachia’s former mining regions regularly attest to this truth. Strip mining has left thousands of square miles of high terrain in Appalachia alone damaged and unclaimed.
Operators just pushed overburden from the mountain mines downslope for 25 years, resulting in landslides, erosion, sedimentation, and flooding.
The remaining weak high walls, which are frequently 100 feet tall, disintegrate and crumble, upsetting drainage patterns and significantly polluting the water.
When the protective plant cover is gone and the remaining soil is not maintained, erosion accelerates significantly.
According to studies, the river flows from some mines contain up to 1,000 times more sediment than flows from places that aren’t mined.
More than 400,000 acres of mined soil had gullies deeper than one foot, according to a 1979 analysis by the Department of the Interior.
High levels of erosion and sedimentation worsen water quality, fill lakes and ponds, contaminate water supplies, raise the cost of water treatment, and hurt the reproduction and feeding of some fish.
It is indisputable that strip mining has negative and detrimental repercussions. The most noteworthy effects of strip mining on the environment are listed below.
1. Damage to habitats and landscapes
Strip mining refers to the process of removing rocks and soil to access the coal below.
If a mountain is blocking a coal seam inside, it will successfully burst or be destroyed, leaving a ruined landscape as well as disturbing ecosystems and wildlife habitats.
Mountaintop removal mining techniques have devastated 300,000 acres of virgin hardwood forest in West Virginia.
It is essential to consider “mine subsidence” while we are talking about how mining operations affect the terrain.
These events take place in subterranean mines. The land surface sinks or subsides and creates a sinkhole when the mine’s ceiling falls.
2. Deforestation and Erosion
Trees are felled or burned, vegetation is uprooted and removed, and the topsoil is scraped off as part of the process of making room for a coal mine.
This causes the soil to erode and the land to be destroyed, rendering it useless for crop production and harvesting.
Rainwater can wash away the weakened topsoil, carrying contaminants into rivers, streams, and other bodies of water.
As they move downstream, they could endanger aquatic and terrestrial species and obstruct river channels, which can lead to flooding and in turn lead to biodiversity loss.
3. Pollutes Ground Water
Minerals from the degraded land may seep into the groundwater and contaminate rivers with hazardous compounds to human health.
For instance, acidic water may drain from abandoned strip mines due to acid mine drainage.
Rocks containing the mineral Pyrite, which contains sulfur, have been found by mining. When this mineral comes into contact with air and water, sulfuric acid is created.
The liquid acid can escape into underground water sources and enter rivers and streams when it rains.
75% of West Virginia’s rivers have been contaminated by these processes and others. Residents’ access to high-quality water will be substantially impacted by this.
In addition to the water contamination brought on by mining, valley filling has buried more than 1000 natural streams (excess mining waste).
4. Health Risks
Black lung disease can be brought on by breathing in coal dust. The people most affected are those who work in mines and those who live in nearby communities.
Residents who live close to strip mines are more likely to have hypertension, cardiovascular disease, kidney disease, and COPD.
5. Displacement of Communities
People are forced to relocate due to all these negative effects, including the deteriorating quality of the air and water they breathe, as well as the increasing exploitation of their own country by coal mines.
The result of all this is barren terrain that is still poisoned years after a coal mine closes.
Although many countries require recovery plans for coal mining areas, it will take time and effort to reverse all the environmental harms caused by depleted water sources, destroyed habitats, and poor air quality.
There is a severe state of disarray throughout the land.
Between 1930 and 2000, mining in the US changed the natural landscape of about 2.4 million hectares [5.9 million acres], the majority of which was once forest.
Due to the extensive soil degradation caused by the mining process, attempts to reseed land damaged by coal mining are problematic.
For instance, just 20 to 30 percent of U.S. reforestation programs in Montana were successful, while in some sections of Colorado, only 10 percent of the oak and aspen saplings that were planted survived.
According to a 2004 assessment, mining in China has degraded the quality of 3.2 million hectares of land.
The general repair rate of mine wastelands was only 10–12% (the ratio of reclaimed land to the total devastating land).
Advantages of Strip Mining
The following are the advantages of strip mining
- It is significantly more efficient than underground mining
- It is safer than underground mining
- It is less expensive.
1. It is significantly more efficient than underground mining
The recovery rate of materials, according to those who support strip mining, is higher.
The amount of material that can be recovered is thought to be between 80 and 90 percent, as opposed to the 50% recovered utilizing tunnel mining.
Since tunnels don’t need to be dug and supported, strip mining is also thought to be a lot faster process.
Minerals don’t have to be lifted through extensive pathways to reach the surface as a result.
In other words, strip mining is a considerably more effective method of recovery and transport.
2. It is safer than underground mining
Because strip mining only involves the surface, employees are not at risk from underground mining’s inherent risk of tunnel collapse.
In addition, businesses must reclaim any land they use for strip mining.
This merely implies that they must restore the excised areas with vegetation after covering them with topsoil.
3. It is less expensive.
Strip mining is not very expensive. The overburden is only partially removed by this kind of mining, despite the employment of large, powerful machinery.
There is no need to dig tunnels, as was previously suggested.
Mining operations have had substantial negative effects on the environment, including water pollution, land degradation, biodiversity loss, air pollution, an increase in health problems, vibration, land subsidence, landslides, and surface and subterranean water contamination.
As a result, the governments of various countries should largely offer technical assistance to local mine stakeholders, such as through facilitating training.
Mine waste should be controlled and converted into non-harmful waste before being released into adjacent water bodies, and new environmentally friendly technology needs to be developed and deployed throughout the extraction and processing.
Top 5 Environmental Impacts of Strip Mining – FAQS
Just as the demand for coal in our daily activities increases thereby leading to frequent mining it has been advised that Eco-friendly Equipment should be used. Mining companies wanting to reduce their environmental impact can switch to more eco-friendly equipment. Battery-driven mining equipment is often powerful enough to replace diesel-driven options. Replacing diesel engines with electric engines where possible, can significantly reduce the amount of CO2 produced by mining operations. In general, the mining industry is already moving in the direction of electric equipment, with more and more mining manufacturers offering eco-friendly alternatives. Some are making more significant commitments like Swedish mining equipment manufacturer Epiroc, which plans to be 100 percent electric within the next few years.
Are there alternatives to Strip Mining?
Just as the demand for coal in our daily activities increases thereby leading to frequent mining it has been advised that Eco-friendly Equipment should be used. Mining companies wanting to reduce their environmental impact can switch to more eco-friendly equipment.
Battery-driven mining equipment is often powerful enough to replace diesel-driven options. Replacing diesel engines with electric engines where possible, can significantly reduce the amount of CO2 produced by mining operations.
In general, the mining industry is already moving in the direction of electric equipment, with more and more mining manufacturers offering eco-friendly alternatives. Some are making more significant commitments like Swedish mining equipment manufacturer Epiroc, which plans to be 100 percent electric within the next few years.
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Ahamefula Ascension is a Real Estate Consultant, Data Analyst, and Content writer. He is the founder of Hope Ablaze Foundation and a Graduate of Environmental Management in one of the prestigious colleges in the country. He is obsessed with Reading, Research and Writing.