5 Chief Pros and Cons of Strip Mining

xcritical mining

To transport directly up the sides of pit walls, special conveying techniques are under development. As a pit is deepened, more and more waste rock must be stripped away in order to uncover the ore. Eventually there comes a point where the revenue from the exposed ore is less than the costs involved in its recovery. The ratio of the amount of waste rock stripped to ore removed is called the overall stripping ratio. The break-even stripping ratio is a function of ore value and the costs involved. The walls of a pit have a certain slope determined by the strength of the rock mass and other factors.

xcritical mining

Contour strip mining is a type of area strip mining that is used on hilly or mountainous terrain. This method involves removing the overlying rock and soil layers in a series of parallel strips that follow the contours of the landscape. The waste rock and soil are then placed in the lower strips to create a stable base for the next strip. Open-pit mining often (but not always) results in a large hole, or pit, being formed in the process of extracting a mineral.

The difference in the quantity of explosives required to fragment rock in place versus fragment and cast or throw the rock across the active pit and into the previous pit is cost-effective. Many surface strip mines use explosives to move overburden in addition to the primary swing equipment (dragline or continuous excavator), displacing up to 35% of the overburden by cast blasting. When cast blasting is used, the dragline may excavate from the spoil side of the pit, sitting on the leveled, blasted overburden.

Strip mining is also considered a much quicker procedure as tunnels don’t need to be dug and supported. As a result, minerals don’t need to be lifted on long routes to get to the surface. In other words, retrieval and transport are so much more efficient using the strip mining technique. There are a number of explosives used, but most are xcritical courses scam based on a slurry of ammonium nitrate and fuel oil (ANFO), which is transported by tanker truck and pumped into the holes. When filled with ANFO, a blasthole 400 mm (about 16 inches) in diameter and 7.5 metres (about 25 feet) deep can develop about one billion horsepower.

For example, low-grade Cu ore can be extracted by means of sulfuric acid heap leaching. In this process, crushed Cu ore is continuously leached with sulfuric acid until most of the Cu is solubilized due to both the high acidity and formation of Cu-sulfate complexes. Spent acid solutions, usually contaminated with other metals, must be neutralized and stored in lagoons or impoundments. Gold mining also produces vast quantities of spent ores and liquid process streams that usually contain residual levels of cyanide ion (CN–) complexes. Metal–cyanide complexes are usually either stable in the soil environment or biologically degraded into nontoxic forms of N (see Chapter 5).

What is Strip Mining?

xcritical mining

This can include planting vegetation, reshaping the land, and creating wildlife habitats. Nearby water sources can become contaminated due to the dumping of excavated material, as well as from the use of extraction solvents. Strip mining also releases toxins and dust in the air resulting in poorly controlled contamination. For instance, permanent loss of ecosystems results from when valley fills frequently bury headwater streams. Also, several endangered species have been threatened and has resulted in loss of biodiversity because of the destruction of large portions of deciduous forests.

Where is strip mining most common?

We can use them as an alternative to burning coal which releases loads of greenhouse gas emissions and eats up our natural resources. In European nations, more than 50% of prior mined lands are rehabilitated as forest or grass lands. Though, in China more than 70% of the mined lands are improved for farming purposes since the enormous population and a scarcity of fertile farmlands make this crucial. Strip mining is only a temporary use of land, so it is imperative to restore the land as soon as mining is over to save the land.

Of the several techniques for determining which of the blocks should be included in the final pit, the most common is the floating cone technique. In two dimensions the removal of a given ore block would require the removal of a set of overlying blocks as well. All of these would be included in an inverted triangle with its sides corresponding to the slope angle, its base lying on the surface, and its apex located in the ore block under consideration. The economic value of the ore block at the apex of the cone would be compared with the total cost of removing all of the blocks included in the cone.

Displacement of Communities

Strip mining is a method of extracting coal reserves by removing overburden in rectangular blocks known as pits or strips, using equipment like draglines or continuous excavators to mine and move the overburden. The process involves drilling, blasting, overburden casting, and coal removal in a sequential manner within adjacent pits. 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. Strip mining involves a series of steps that begin with the removal of overburden, which refers to the layers of soil, rock, and vegetation covering the target resource. This overburden is typically moved using heavy machinery, such as bulldozers and excavators.

  1. Strip mining is a controversial practice owing to the fact that it affects topography, vegetation and water resources.
  2. Because of their increasing efficiency with larger sizes, the land footprint of a coal power plant can be quite substantial.
  3. The thickness (that is, the height) of the benches depends on the type of deposit, the mineral being mined, and the equipment being used; for large mines it is on the order of 12 to 15 metres (about 40 to 50 feet).
  4. They enable efficient mineral extraction while also providing the means to mitigate environmental impacts and restore mined land.
  5. This technique is commonly used for extracting coal and other minerals that are found in horizontal seams.

Energy economics

The mineral layer is covered by an even thickness of overburden composed of soft top soil and weathered rocks in succession. The soft and unconsolidated overburden can be stripped and removed by dragline or shovel to expose a coal seam and metallic ore. The overburden xcritical reviews might need drilling at grid spacings of 7.5 m × 7.5 m–15 m × 15 m depending on its hardness and thickness. Production drilling and blasting continue in advance with the movement of dragline/shovel.

Other than water pollution due to mining activity, more than 1000 natural streams have been buried due to valley fill (excess mining waste). Mining has uncovered rocks which comprise of the sulphur-bearing mineral, Pyrite. This mineral when in contact with air and water, produces sulphuric acid. When it rains, the watery acid makes its way into rivers and streams and can also leak into underground sources of water.

The mining process starts at the edge of the deposit and moves inward in successive strips until the entire deposit is mined. Strip mining is a method of mining that involves removing the surface layers of earth to access mineral deposits located close to the surface. This technique is commonly used for extracting coal and other minerals that are found in horizontal seams. By stripping away the overburden, or the layers of soil and rock covering the mineral deposit, miners can efficiently reach and extract the desired materials. Strip mining is commonly used to extract thin coal seams and lignite that are very close to the ground surface. The strip mining process is suitable for fairly flat, shallow, single-seam coal, lignite, and other bedded deposits.

Contour mining progresses in a narrow zone following the outcrop of a mineral seam in mountainous terrain. Recycling – Recycling can reduce the demand for new minerals and decrease the need for strip mining. By recycling metals such as copper, gold, and silver, we can reduce the environmental impact of mining activities.

In case of a deep-seated bedded deposit within permissible stripping ratio the overburden is removed by opening successive and progressive benches. The multiple seam mining is done by operating first pair of overburden and coal bed at a time and followed by second and third pairs in sequence. Finally, the total overburden rocks, stockpiled around the mine opening, are backfilled to the abandoned mine. Surface mining refers to a category of mining where soil and rock overlying the mineral deposit are removed. There are several types of surface mining, and strip mining counts as one of them. It has been estimated that more than two-thirds of the world’s yearly mineral production is extracted by surface mining.


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