Coal Mining Panel Width Analysis

Added on 2020-03-01

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Long Wall Mining Operation1LONG WALL MINING OPERATION by (Name)The Name of the Class (Course) Professor (Tutor) The Name of the School (University) The City and State where it is located The Date

Long Wall Mining Operation2PARAMETERDISCUSSIONMining Methods Long wall is a type of large scale mechanized mining method. It involves mining seams of coal in slices. There are three longwall mining methods: the Single Pass Longwall mining method (SPL), Multi-Slice Longwall mining method (MSL) and Longwall Top Coal Caving mining method (LTCC) (Riaza and Gupta, 2015). Each is used depending on the topography of the area and the thickness of the coal being mined. The single pass method is used when the seams are less than six meters in thickness. The seam of coal isdivided into slices of predetermined length and extracted by the workers usingequipment suited for the operation. The Multi Slice Longwall applied when seams of coal are more than six meters in thickness. The mining is then done in horizontal slices. Economically speaking, the investment costs are twice higher for Multi Slice Longwall method as compared to Longwall top coal caving method. Compared to the Multi Slice Longwall method, the Longwall Top Coal Caving method is more effective as it is more economical as it requires less labour and equipment and can be applied to thicker seams more easily (He et al., 2013). Developed by the French in their coal mining industry, the longwall top coal caving method has one face of the seam operated on the base while the coal that is left on top is taken from the window through the roof support.Pillar SizesThe size of the pillar, according to Woodruff (2016) depends on the strengthof the coal seams, the nature of the roof and the hardness floor of the mine,the effect of the gases available in the atmosphere and how long the pillars

Long Wall Mining Operation3will have to support the coal seam, otherwise known as the time dependentstrain. When the coal is strong, the mining operation will require pillars withlesser width. The pillar edges will be affected by the strength of the roof; ifthe roof is strong, the edges will be crushed. The strain on the pillars increaseswith the passage of time while the load carried remains constant. Thus if thepillar is not sufficient in size, it may fail despite being stable in the earlystages. Camp asserts that pillars are important for the safety of the workers in themines thus the main purpose of the pillars that are placed at the head gateentry and the tail end entry is supporting the overlying strata (2016). Thehead gate is used for transporting the miners, coal and the supplies while thetail entry is used for ventilating the mine from dust. According to Bise, thesize of the pillars to be used depends on the thickness of the seams, theequipment being used and the depth at which the mining is to be done (2013).When the pillar is too thick, there are losses made since the coal at the pillar isnot mined. Though there is a possibility to mine the coal at the pillar as themining advances, there is still coal loss by a marginal percentage when retreatmining is applied. When the pillar is too thin, there is the possibility that thecoal roof will collapse into the mining area (Absalov, 2016). The collapse willlead to workers being harmed, slowing down the process due to disruption ofnormal flow of work, and a loss of a percentage of the coal that was to bemined due to disturbance to the strata and the mix-up with dust and otherundesirable elements. A typical pillar measures six to forty five meters in

Long Wall Mining Operation4width and six to twelve meters in length. The exact size is determined y themining conditions of the area. To aid the support of the pillars, additionalsupport is provided by roof bolting (Singhal, 2014). Choice of a PanelWidth When Mining. The panel width when mining is important during the development stages. Italso determines the technical economic indices of the scope and theproductivity of the production unit according to (Bondarenko, Kovalevs'ka, &Ganushevych (2014). It determines the placements of the head and tailentries. Setting up the required machines and workflow depends on the size ofthe panel and could take averagely nine to twelve months. The size alsodetermines the amount of coal that is going to be extracted in addition to thetype of equipment that will be used. The perimeter cut out for the panelshould allow for the continuous operation of the mine using the equipment inuse. Usually, the equipment in use is self-advancing hydraulic roof supports,an armored conveyor belt parallel to the coal wall face to transport the coal assoon as it mined to the designated area and the coal shearing machine thatallows for the coal to be sheared and placed on the conveyor belt. Normally,if the quality of the mine is favorable, up to 80% of the coal being mined willbe recovered(Wain, 2014). Around the panel, there should be 10 to 15 feetspace left to allow for sufficient room for the miners to work in addition to theequipment.Best sequence of mining for a longwall operation to There are two ways of mining coal efficiently: the retreat and advance longwall methods (Richards, & Szwilski, 2012). When the coal is less than 6 meters deep the best method is to use the single slice longwall method. While if the coal mine is going to be more than 6 meters, the economics safety and