How much does a longwall cost?
The cost of a typical longwall installation is $9 million; total capital cost of the technology per ton of coal mined over the life of a system is about $1,50.
Where is longwall mining used?
Most longwall mining occurs in the coal basins of New South Wales and Queensland.
What is longwall mining method?
longwall mining Longwall mining is an underground method of excavating coal from tabular deposits, as well as soft mineral deposits such as potash. Large rectangular blocks of coal are defined during the development stage of the mine and are then extracted in a single continuous operation.
Is longwall mining expensive?
Today, longwall has evolved into the most modern, efficient, and safe mining technique going. It is also the most expensive. Currently, about 5 percent of US coal is mined by longwall. Estimates of longwall production by 1985 range from 15 to 25 percent.
How does longwall mining compare to room and pillar mining?
Longwall has better resource recovery (about 80% compared with about 60% for room and pillar method), fewer roof support consumables are needed, higher volume coal clearance systems, minimal manual handling and safety of the miners is enhanced by the fact that they are always under the hydraulic roof supports when they …
Why longwall mining is not applicable in every Indian coal seam?
… The majority of longwall panels installed in the India could not achieve the desired targets due to lack of knowledge of geo-mining conditions, non-available of spared parts, dynamic loading on the powered support and under rated shield support selection.
Who invented longwall mining?
England
The basic idea of longwall mining was developed in England in the late 17th century. Miners undercut the coal along the width of the coal face, removing coal as it fell, and used wooden props to control the fall of the roof behind the face. This was known as the Shropshire method of mining.
What are the advantages and disadvantages of longwall method?
Despite its disadvantages of low flexibility, low selectivity, and high capital investment, longwall mining is recommended because of its high mechanization, productivity, recovery, production rate, safety, low operating costs, and continuous methodology (Nieto, 2011).
How does longwall mining affect the environment?
IMPACTS FROM LONGWALL MINING The release of methane gas into the atmosphere, water and homes. At least one home explosion has been documented as a result. Ground cracks and landslides: frequently these render the land unusable. Depopulation of rural areas in the coalfields where longwall mining has occurred.
How many longwall mining are there in India?
Out of the total 28 mechanized longwalls installed in India employing powered roof supports there are currently around 20 longwalls operating. Twelve of these are owned by the state-owned Coal India (CIL).
What equipment is used in longwall mining?
Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports. The entire process is mechanized. Longwall mining machines are about 800 feet (240 meters) in width and 5 to 10 feet (1.5 to 3 meters) tall.
How big is a longwall coal mine?
Longwall mining is a deep mining technique capable of fully extracting huge panels of coal, frequently up to 1,500 feet wide and two miles long. Coal shearing machines known as “continuous miners,” remove a long wall of coal in a single slice as hydraulic jacks hold up the roof above and in front of the machine.
How is longwall mining harmful to the environment?
This practice directly impacts our personal health and that of our surrounding environment. Report prepared in connection with Act 54, the state law that regulates bituminous coal mining in Pennsylvania, reveal the devastating effects of coal mining generally and longwall mining in particular.
Which is better Longwall or room and pillar mining?
Longwall has better resource recovery (about 80% compared with about 60% for room and pillar method), fewer roof support consumables are needed, higher volume coal clearance systems, minimal manual handling and safety of the miners is enhanced by the fact that they are always under the hydraulic roof supports when they are extracting coal.
How is a tailgate road formed in longwall mining?
In thinner seams the advancing longwall mining method may be used. In the retreat type, the panel is a face connecting them both. Only the maingate road is formed in advance of the face. The tailgate road is formed behind the coal face by removing the stone above coal height to form a roadway that is high enough to travel in.
