What is overburden removal in mining?
Overburden removal refers to the removal of top-soil to expose the coal seams making them ready for mining. Any delay in this process impacts the future-readiness of the company to sustain output levels.
What happens to overburden in surface mining?
Overburden is removed during surface mining, but is typically not contaminated with toxic components. Overburden may also be used to restore an exhausted mining site during reclamation.
How is overburden removed?
The overburden is usually removed by an excavator or scraper and the removed material can then be used to backfill earlier quarried areas. The hard rock aggregate source itself is most commonly worked by drilling and blasting, or more rarely by mechanical ripping.
What is removed during surface mining?
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 …
Where does overburden go during a mining operation?
In open pit mining, the operator first removes the overburden to uncover the coal seam. The overburden may be placed on adjacent, undisturbed land, or it may be transported by belt or rail to the other end of the same mine or to an exhausted mine that needs to be backfilled.
How does mining affect human health?
Coal mining leads U.S. industries in fatal injuries, and miners have suffered prolonged health issues, such as black lung disease, which causes permanent scarring of the lung tissues. Surface mining destroys forests and groundcover, leading to flooding and soil erosion.
Is surface or subsurface mining worse?
Subsurface mining is actually less disruptive to the earth and produces less waste than surface mining, but it’s also much less effective and more dangerous. Many workers die in mine collapses, which then also leaves behind a large hole from caving in of the ground above.
What are the pros and cons of surface mining?
Surface mines offer advantages and disadvantages when compared to underground mining. Amongst the advantages are that it is cheaper, can recover more of the resource (usually up to 100% within the mining excavation), is safer and can use larger-scale mining equipment offering higher production rates.
Why is overburden bad?
The overburden soil is also highly acidic, at a pH of 2 or 3, and so doesn’t support many trees, bushes or other flora. Furthermore, dumping loose topsoil onto mountainous areas, such as in Appalachia, can cause landslides, and uncompacted soil can run off and clog waterways, setting the stage for flash floods.
What are the disadvantages of surface mining?
Disadvantages include its high visibility, the large-scale surface disturbance and the limited economic depth to which mining can take place. Environmentally responsible miners are always looking at new ways to minimise the impacts of their operations on the environment.
Why is strip mining bad?
Strip mining destroys landscapes, forests and wildlife habitats at the site of the mine when trees, plants, and topsoil are cleared from the mining area. This in turn leads to soil erosion and destruction of agricultural land. When rain washes the loosened top soil into streams, sediments pollute waterways.
What are the negative effects of mining?
Across the world, mining contributes to erosion, sinkholes, deforestation, loss of biodiversity, significant use of water resources, dammed rivers and ponded waters, wastewater disposal issues, acid mine drainage and contamination of soil, ground and surface water, all of which can lead to health issues in local …
How does Overburden Management affect surface mining projects?
Overburden handling has important impacts on surface mining projects and has to be carefully planned considering both mining activities and site rehabilitation [1], [2].
How are overburdens removed in open pit mining?
The selection of methods for overburden removal and disposal in open pit mining involves geotechnical, topographical and typical site aspects, as resumed in Table 1 [3], [7], [8], [9], [10]. Fig. 2 represents also a summary for equipment selection.
Where does the overburden go in coal mining?
As mining progresses, the overburden and innerburden are placed in piles in previously mined pits where the bottom seam has been completely removed, using draglines and auxiliary excavating equipment.
How is regrading used in surface coal mining?
Large scale earth moving equipment is used to excavate and remove coal from lower layers. The equipment used depends on the method and scale of the surface mining method being employed. Regrading begins as coal excavation continues. Once coal removal is complete, final regrading takes place and the area is revegetated.