Open Cast Mining Advantages And Disadvantages
Melissa Alvarado
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Mining is a complicated process, and the decisions to mine underground rather than above ground must be carefully considered. Subsurface mining offers several potential advantages, including access to minerals and ores that are otherwise difficult or impossible to reach using traditional open-pit mining techniques.
open cast mining advantages and disadvantages
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It can also provide greater efficiency in the extraction process as miners do not need to waste time hauling material up from deeper areas. In surface mining, larger areas need to be excavated to recover materials, and this can lead to extra use of resources.
Since subsurface mining does not require the removal of large amounts of overburden on top of the ore, it is much more environmentally friendly than open-pit mining. It also requires less energy and can be completed in a shorter period.
Subsurface mines are some of the safest, according to records kept by the Mine Safety and Health Administration. They have less risk of surface hazards like flooding, subsidence, and landslides that can occur with open-pit mining. The vast terrains can lead to less human contact with machines and equipment, leading to another factor in the safety of subsurface mining.
Subsurface mining uses various methods for survey to locate deposits underground. This makes the miners more precise and less wasteful when extracting materials. By using an advanced tunneling method, subsurface mining can access valuable minerals easier than surface mining, making it more profitable in some cases.
The conditions of subsurface mining can be hazardous to the miners. Since they are underground, miners may need to use safety equipment and protective clothing which can be costly. Coal dust or other air particles can also cause respiratory problems. In addition, the tunnels are sometimes unstable, and there is a risk of cave-ins.
Mining deep into the earth can disrupt groundwater and aquifers and cause water contamination from the seepage of mining chemicals. This can lead to health risks for people living near the mining site.
Subsurface mining requires more intricate knowledge and techniques than surface mining. This means miners need a higher skill level and specialized equipment, making it more expensive to start a mining site. Even though it can be more profitable over time, the initial costs of setting up a subsurface mine can be high.
Overall, there are both advantages and disadvantages to subsurface mining. It is important to weigh these factors carefully before deciding if this type of mining is right for your project. Subsurface mining can offer several potential benefits, such as lower environmental impact and increased safety. However, it also has several disadvantages, such as the potential for hazardous conditions and water contamination. These factors can help you decide if subsurface mining suits your project.
In the previous topic, we saw which are some of the advantages that can make the surface open pit mining methods superior method compared to the underground mining. However, underground mining has its own advantages. And finally, the ultimate decision to mine from the surface or from underground comes down to the specific characteristics of the deposit. In particular, mineral deposits can occur in very different forms and they may contain a very wide variety of minerals.
For civil construction, we can consider the deposits of sand, clays, gravel, rocks, and all of the stones that are usually used for making cement. Then we have placer deposits where mineral grains are deposited from water in rivers and beaches, such as gold, tin, rutile, zircon, sapphire, and diamond. Then we have residual deposits where valuable minerals have Being concentrated through the leaching away of gangue minerals under tropical climatic conditions so as to form iron, and manganese oxides, and nickel silicates, and aluminum oxides.
Phosphate deposits such as from bones or bird feces. Sedimentary iron and manganese deposits, from times in the distant geological past when oxides of iron and manganese crystallize from seawater and were preserved as geological layers.
Opencast mining, also known as surface mining or strip mining, has disadvantages that include disturbance of the environment and local ecosystems, exposure of radioactive elements and contamination of freshwater sources. The use of heavy machinery and blasting techniques also create environmental pollution.
The presence of pits and ponds around mines contributes to groundwater contamination. Rock blasting creates fractures in the rock, allowing mine drainage leakage from abandoned mines into groundwater aquifers. Contaminated groundwater typically has a higher pH and total hardness, and contains dissolved sulfate. Radioactive elements produced from rock slurries can also pollute groundwater by leaking into fractured bedrock. Surface mining also contributes to air pollution through the release of toxic compounds. These particulates react with water vapor to produce acid rain.
Surface coal mining, for example, has contaminated more than 5,000 miles of streams in the eastern United States, impacting aquatic ecosystems and public drinking water supplies. Although surface mining reduces production costs and poses fewer health dangers to miners compared to underground mining, surface mining also requires blasting into rock and changing the landscape, increasing the risk of mountainside erosion, mudslides and compaction of the soil. Some states, such as Oklahoma, require the reclamation of old surface mining locations in order to restore their usability.
Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels.
In North America, where the majority of surface coal mining occurs, this method began to be used in the mid-16th century[2] and is practiced throughout the world in the mining of many different minerals.[3] In North America, surface mining gained popularity throughout the 20th century, and surface mines now produce most of the coal mined in the United States.[4]
Advantages of surface mining include lower cost and greater safety compared to underground mining. Disadvantages include hazards to human health and the environment. Humans face a variety of health risks caused by mining such as different cardiovascular diseases, food, and water contamination. Habitat destruction, alongside air, noise, and water pollution, are all significant negative environmental impacts caused by the side effects of surface mining.
Strip mining is the practice of mining a seam of mineral, by first removing a long strip of overlying soil and rock (the overburden); this activity is also referred to as overburden removal. It is most commonly used to mine coal and lignite (brown coal). Strip mining is only practical when the ore body to be excavated is relatively near the surface and/or is mostly horizontal.[5] This type of mining uses some of the largest machines on earth, including bucket-wheel excavators which can move as much as 12,000 cubic meters (16,000 cu. yd.) of earth per hour.
There are two forms of strip mining. The more common method is area stripping, which is used on fairly flat terrain, to extract deposits over a large area. As each long strip is excavated, the overburden is placed in the excavation produced by the previous strip.
Contour mining involves removing the overburden above the mineral seam near an outcrop in hilly terrain, where the mineral outcrop usually follows the contour of the land. Contour stripping is often followed by auger mining into the hillside, to remove more of the mineral. This method commonly leaves behind terraces in mountainsides.
Open-pit mining refers to a method of extracting rock or minerals from the earth through their removal from an open pit or borrow. This process is done on the ground surface of the earth [6] It is best suited for accessing mostly vertical deposits of minerals. Although open-pit mining is sometimes mistakenly referred to as "strip mining", the two methods are different (see above).
Mountaintop removal mining (MTR) is a form of coal mining that mines coal seams beneath mountaintops by first removing the mountaintop overlying the coal seam. Explosives are used to break up the overburden (rock layers above the seam), which is then removed. The overburden is then dumped by haul trucks into fills in nearby hollows or valleys. MTR involves the mass restructuring of earth in order to reach coal seams as deep as 400 feet (120 m) below the surface. Mountaintop removal replaces the original steep landscape with a much flatter topography. Economic development attempts on reclaimed mine sites include prisons such the Big Sandy Federal Penitentiary in Martin County, Kentucky, small-town airports, golf courses such as Twisted Gun in Mingo County, West Virginia and Stonecrest Golf Course in Floyd County, Kentucky, as well as industrial scrubber sludge disposal sites, solid waste landfills, trailer parks, explosive manufacturers, and storage rental lockers.[7]
This method has been increasingly used in recent years in the Appalachian coal fields of West Virginia, Kentucky, Virginia, and Tennessee in the United States. The profound changes in topography and disturbance of pre-existing ecosystems have made mountaintop removal highly controversial.[8]
Advocates of mountaintop removal point out that once the areas are reclaimed as mandated by law, the technique provides premium flat land suitable for many uses in a region where flat land is rare. They also maintain that the new growth on reclaimed mountaintop mined areas is better able to support populations of game animals.[9]
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