Strip mining Surface Mining, Reclamation & Restoration

Compared with other mining forms, strip mining attains a much higher recovery rate of materials, which is approximately 80%-90%, whereas underground mining only offers a roughly 50% mineral recovery rate. All surface or strip mining initially eradicates the vegetation, rock sediment, and soil spread over the surface to uncover and remove coal from an underground mineral seam or coal deposit. I should also mention, phosphate mining operations are very similar to coal mining operations. 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.

  1. Open-pit mining refers to a method of extracting rock or minerals from the earth through their removal from an open pit or borrow.
  2. This is not unlike the ecological islands created in the southwestern United States from climate changes and vertical zonation of vegetation.
  3. A mining company may choose this option if the cost of transporting overburden for backfill exceeds the cost of creating an impoundment.
  4. The creation of the open pit can also alter the topography and drainage patterns of the area, leading to soil erosion and water pollution.
  5. While we’re discussing effects on landscape due to mining operation, it’s imperative to discuss a scenario known as “mine subsidence”.

Alternative Mining Methods – Alternative mining methods such as underground mining and in-situ mining can be used to reduce the impact of mining on the environment. These methods are often more expensive than strip mining but are less damaging to the environment. The object of blasting is to fragment the rock and then displace it into a pile that will facilitate its loading xcritical website and transport. In large open pits the main implements for loading are electric, diesel-electric, or hydraulic shovels, while electric or mechanical-drive trucks are used for transport. The size of the shovels is generally specified by dipper, or bucket, size; those in common use have dipper capacities ranging from 15 to 50 cubic metres (20 to 65 cubic yards).

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Economic factors such as costs and expected revenues, which vary with grade and block location, are then applied; the result is an economic block model. Some of the blocks in the model will eventually fall within the pit, but others will lie outside. 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.

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The size of the trucks is matched to that of the shovel, a common rule of thumb being that the truck should be filled in four to six swings of the shovel. Thus, for a shovel of 15-cubic-metre capacity, a truck having a capacity of 120 to 180 tons (four to six swings) should be assigned. The largest trucks have capacities of more than 350 tons (about 12 swings) and are equipped with engines that produce more than 3,500 horsepower; their tire diameters are often more than 3 metres (10 feet).

⛏️ Comparing Different Types of Surface Mining

While efforts in recent years have resulted in some changes to mining practices, strip mines remain devastating to local ecosystems, landscapes, and water sources. Auger miners focus on the highwall at a point where the wall has reached heights that render the removal of overburden unprofitable. Miners drill into the sides of this wall to extract further coal resources from embedded seams. In many cases, mining businesses will resume coal mining via different methods, such as auger, to reach a deeper ore body after contour mining endeavors cease. Unlike area mining, contour mining utilizes smaller equipment, such as backhoes and power shovels.

The researchers calculate that the valley fills can hold a year’s worth of rainfall, ten times more than the thin, clay-rich pre-mining soils. In Oklahoma, a study conducted by Nathan Meleen dealt with a mix of both flat and hilly terrain. The findings were published as a doctoral dissertation in 1977 by Clark University.

Open Pit Mining

Techniques such as selective mining, where only high-grade ore is extracted, can reduce the volume of material removed and minimize waste. Regulations – Governments can regulate strip mining activities to ensure that mining companies follow environmental regulations and minimize their impact on the environment. This can include setting limits on the amount of land that can be mined, regulating the use of toxic chemicals, and requiring companies to clean up the land after mining activities have ended. The walls of a pit have a certain slope determined by the strength of the rock mass and other factors. The stability of these walls, and even of individual benches and groups of benches, is very important—particularly as the pit gets deeper.