Comprehensive Analysis: Long Wall Mining Operation and Methods

This report provides a detailed analysis of long wall mining operations, focusing on critical aspects such as panel width, efficient coal extraction techniques, and the importance of pillar size. It explores how panel width affects coal recovery, equipment selection, and operational efficiency, considering factors like fault lines and geotechnical stresses. The report also examines efficient coal extraction methods, including retreat and advance longwall techniques, highlighting their advantages and disadvantages. Furthermore, it delves into the significance of pillar size in maintaining mine safety and stability, discussing how coal strength, seam thickness, and the duration the pillar supports the roof influence pillar dimensions. Finally, the report outlines various longwall mining methods, including single-slice, multi-slice, and longwall top coal caving, comparing their resource requirements and economic viability. The report uses several references to support the analysis.

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Panel Width
The panel width size determines the positioning of the head and tail entries of the mining
operation. It also determines the amount of coal that can be recovered, the type of equipment to
be used and the amount of time that will be required to properly set up the whole operation (Bise,
2013). Thus, it is very integral to know what dimensions will be used as it charts the way
forward during the developmental stages. In addition, consideration should be made to ensure
that the machines can easily maneuver in the spaces left in between the panels for easy
workflow, movement and safety for the workers. In order to arrive at the optimum width
required for the panel, there has to be calculations done to ascertain that the chosen width will
ensure that the mining will be the most efficient and productive. This is putting into
consideration the alignment of the coal seams and the variable costs of the conveyor belt and the
operational equipment whose costs are dependent on the panel width length.
When the panel has fault lines and geotechnical stresses, the recovery rate decreases
considerably despite the panel width because there is need for sterilization along the panel width
directly proportional to the extent of the risk involved. This type of scenarios negates any
benefits that may have been gained by increasing the panel width. It also has to be put into
consideration if the capital cost can be met in addition to the operational costs involved (Camp,
2014). The panel width cannot be increased if the equipment available is not able to cater for the
arising needs and new equipment cannot be acquired, or if when the new equipment is acquired,
the revenue achieved is reduced or tends in the negative. Therefore putting into consideration all
these, the panel width that is chosen is the one that yields optimum mining results without
exerting unnecessary strain on the whole operation economically and also using the equipment
available.

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Efficient Extraction Of Coal
The retreat and advance longwall methods are used to mine coal efficiently. They are
used depending on the equipment available and the method that the mining team sees fit for the
operation. The extraction of the coal starts from the farthest end of the coal seam along the panel
width and proceeds towards the entry of the mine when using the retreat method unlike the
advance method that has the mining start from the main entrance and progresses towards the end
of the mine (Kesler et al, 2015). Conveyors are used when mining to transport the coal that has
been mined to the collection points.
In the advance system there has to be continuous operations on either side of the entries
in order to ensure that the gob formed when the roofs cave in are removed and the area is still
work conducive (Bondarenko et al 2014). This is a disadvantage to the method as there is wasted
manpower and resources used to keep the channels open that would have otherwise been used to
do more productive mining work. The ventilation systems of the advance method must also be in
place as the dust that accumulates on the equipment causes problems for the workers’ health and
the overall conditions of the equipment.
Pillar Size
The size of the pillar is of paramount importance in the mining process. The pillar holds
up the coal seam and ensures that there are fatalities in the mines (Galvin, 2016). It also makes it
possible for the workers to be safe and for the equipment to have enough room to maneuver the
mining site. The strength and the size of the pillar is influenced by the strength of the coal, the
thickness of the seams, the topographical composition of the roof and the floor and the duration

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which the pillar will have to hold up the coal seam and the gob. These parameters affect the size
of the pillar in the following ways.
Larger pillars are required when the coal seams are weak as the pillars can buckle if not
well propped under the weight of the coals. Larger pillars are also required if they will be
holding up the gob for a much longer period of time due to the time dependent strain that will
reduce the load bearing capacity of the pillar. When the seams are thick, larger pillars will be
required as compared to if the coal seems were less thick, as the overall load that the pillars
should carry will be greater. Care should be taken however to ensure that the size of the pillars is
of optimum dimensions to prevent the wastage of coal that would have otherwise been mined
remaining as part of the gob due to overdesigned pillar sizes.
Methods Of Longwall Mining
There are three methods within the longwall mining category. Longwall mining is used
when the coal seems are of a large scale and require highly mechanized systems for the mining
to effectively take place. According to Camp when the coal seam is less than six meters, the
single slice longwall mining method can be applied (2016). When the coal seam is more than six
meters in vertical thickness, either the multi slice longwall method will be applied or the
longwall top coal caving method will be put in place for the mining process (Singh, 2017).
In these two methods, the amount of resources and equipment used will be more than for
the single slice method due to the apparent scale of manpower that will be required for a
successful operation. In the multi slice method, the coal seam is sliced depending on the most
suitable horizontal slice dimensions, and extracted manually parallel to the hanging wall and the

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footwall. When carefully considered, however, the longwall top coal caving method is much
more economical than the multi slice longwall method as it requires labor and lesser resources as
it is easier to mine the coal especially when the seams are thicker (Wain, 2014). Thus the
operational and initial costs of the operation will be much more for the multi slice method.

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References
Bise, C.J., 2013. Modern American Coal Mining: Methods and Applications, Society for Mining,
Metallurgy and Exploration Incorporated.
Bondarenko, V., Kovalevs'ka, I. & Ganushevych, K., 2014. Progressive Technologies of Coal,
Coalbed Methane, and Ores Mining, Boca Raton, Fla: CRC Press.
Camp, W.G., Heath-Camp, B. & Stokes, A.D., 2016. Managing our natural resources,
Stamford: Cengage Learning.
He, X. et al., 2014. Progress in mine safety science and engineering II: proceedings of the 2nd
International Symposium of Mine Safety Science and Engineering, Beijing, China, 21-23
September 2013, Leiden, The Netherlands: CRC Press/Balkema.
Kesler, S.E. & Simon, A.F., 2015. Mineral resources, economics and the environment,
Cambridge: Cambridge University Press.
C. & B., 2013. Modern American Coal Mining: Methods and Applications, SME.
Riazi, M.R. & Gupta, R., 2015. Coal Production and Processing Technology, CRC Press.
Richards, M.J. & Szwilski, A.B., 2012. Underground Mining Methods and Technology, Elsevier
Science.
Singh, P. et al., 2017. NexGen Technologies for Mining and Fuel Industries (Volume I and II),
Allied Publishers.
Wain, K., 2014. The Coalmining Industry: Of Barnsley, Rotherham And Worksop, Amberley
Publishing Limited.