In longwall mining, a panel of coal, typically around 150 to 300 metres wide, to 3500 metres long. In each panel two or more parallel drifts for ventilation and ore transport are driven along the opposite. Typically, a longwall face retreats at a rate of 50 metres to. Of this, 51% of the production is produced by longwall mines eia, 2006. Furthermore, the slices are as much as three metres thick and are taken by a continuous miner. And our teams experience is vast some longwall members have been in the industry for. This video provides a basic description of the longwall mining method for extracting coal underground. Method of assessment this unit may be assessed in a holistic way with other units of competency. In the longwall system the ore body is divided into rectangular panels or blocks. Most aspects of alternative cutting methods and cutting procedures have been referred to in the longwall section of the fundamentals of coal mining module of this web site and little can be added here. Ug mining methods coal deposits are mined by cutting a network of roads into the coal seam and leaving behind pillars of coal to support the roof of the mine. Technical developments since 1990 have once again established plowing as the preferred longwall mining method for seams below 1. Starting around 1900, mechanization was applied to this method. Approximately 45 longwalls are in operation at a given time.
Riimcu308a install and recover longwall equipment date this document was generated. Since that time, all components of a longwall system have been considerably upgraded in areas such as installed power, conveyor chain speed and capacity, structural integrity. We have been designing and building longwall plows since 1941 and things have come a long way. Caterpillar is the world leader in longwall roof support technology. Later, a fully mechanized method started in europe and began to be used during the 1950s and 1960s in the united states. Pdf geomechanical issues in longwall mining an introduction. Effects of longwall mining on real property value and the tax base of greene and washington counties, pennsylvania december, 2002 page 4. The mines also provided niosh with autocad map files, roof control plans.
Longwall and caving mining methods snu open courseware. There is a tendency to black box the bleeder and gob areas in a model, however this can lead to problems when examining the addition of contaminates in the air stream as they pass though these undefined areas. Today, there are two primary underground extraction methods in use. Conventional mining is the oldest method used today. Wire ropes of 19 to 22mm diameter and 6 to 8m length with safe. A brief comparison of longwall methods used at mining of. Modeling and prediction of ventilation methane emissions of u. Group 7 the joy shearer, introduced in 1976, was the first multimotor shearer and this design concept became the global standard for all longwall shearers. Final report effects of longwall mining pdf format. We suggest you first download these files to your computer. Research report on the coal pillar recovery under deep.
This is the first time a state agency has come out and admitted permanent damage to a stream from longwall mining, says aimee erickson, director of the citizens coal council. According to available records, ongwall mining started l in illinois shortly after 1856 in lasalle county at the lasalle mine of the lasalle county carbon coal company harris 1918. Longwall mining machines are about 800 feet 240 meters in width and 5 to 10 feet 1. Komatsu expanded its worldwide market presence by providing safer, productive, reliable. Other articles where shortwall method is discussed. Modeling and prediction of ventilation methane emissions. By 1940, some referred to longwall mining as the conveyor method of mining, after the most prominent piece of machinery involved. Most longwall mining occurs in the coal basins of new south wales and. Definition of longwall mining a high extraction method of mining along the face of a predefined block of coal, referred to as a panel, while allowing the immediate roof to collapse upon advancement panel configuration panels generally range in size from 500 to 1,000 feet in width and lengths exceeding two miles. The part of this coal seam that is using the mechanized longwall method is accessed by an inclined slope. The most important coal seam in tabas is named c1 with a thickness of 1. Ventilation surveying and modeling of longwall bleeder and. The average daily mining rate for the longwall is 3,300. Coal mining licensingregulatory information refer to unit descriptor.
Local conditions will form the basis for choosing the appropriate mining method pollution prevention and control early planning and careful design of operations are the key to. Longwall mines produce more than 30 pct of all underground coal, up from 5 pct just 15 years ago. Longwall mining in seams of medium thickness comparison of plow and shearer performance under. Average longwall production as reported by mine operators. Joy complete longwall systems represent the ultimate solution for highproduction longwall mining. To date, the annual pr operty tax es generated from longwall coal mining has more than offset the annual tax revenue lost from those surface property assessment reductions related to longwall mining. Both methods are well suited to extracting the relatively flat coalbeds or coal seams typical of the united states. Longwall mining machines consist of multiple coal shearers mounted on a series of selfadvancing hydraulic ceiling supports. This longwall method started in great britain in the late 1600s hatcher 1993.
Longwall longwall mining involves the full extraction of coal from a section of the seam or face using mechanical shearers to cut and remove the coal at the face, which can vary in length from 100350 m. The longwall is operated without a gas drainage system. A coal face is formed between these roadways and the coal is extracted by a mechanical shearer. The primary function of the gate road pillars is to maintain the stability of the headgate and tailgate entries as the longwall panels are mined. Longwall mining began in 17th century england technology advances in 1950s led to use in us in past few decades it has increased due to changes in longwall panel dimensions and improvements in longwall equipment. Multiple seam longwall mining in the us lessons for. In conventional mining, the coal seam is cut, drilled. Adapted to the mining challenges faced by our customers today, cat customized systems for longwall mining include hydraulic roof supports, highhorsepower shearers, automated plow systems and armored face conveyors with intelligent drive technology controlled. The method was successfully tried in 6m thick seam iii at chirimiri colliery of secl. Mining techniques contour area conventional longwall liquid effluents 0. Introduction to longwall mining and subsidence ver2. Monitoring and management of subsidence induced by longwall coal mining activity is licensed by the commonwealth of australia for use under a creative commons by attribution 3. The choice of mining method is an extremely import ant decision affecti ng the entire. Longwall mining is a highly mechaniz ed underground mining sys tem for mining coal.
Joy incorporates bestinbreed shearers, roof supports, face conveyors, stageloaders, crushers, and mobile belt tail pieces to deliver a complete longwall system that is in a class of its own. It is novel in that it incorporates unit operations of different mining methods into the system. Longwall mining in seams of medium thickness peterson cat. Monitoring and management of subsidence induced by. Longwall mining is a highly productive underground coal mining technique. Many of the worlds most productive, recordbreaking longwall operations choose longwall associates custom designs for hardworking, reliable, longlasting mining equipment.
Methane is explosive in concentrations of 515% volume in air and has been the cause of devastating mine explosions around the world throughout the history of coal mining. This mining method which is appropriately applied for soft rock flatlying bedded ore bodies gradually became a widespread mining method amongst european coal mines at the beginning of the 19th century. Cat plows offer worldleading features that other manufacturers cannot and a cost of ownership. As such, it is considered a mining hazard, a greenhouse gas, and a possible energy source. By employing multiple slice longwall mining method.
The face length panel width ranges from 200 to 220 meters. This method removes all of the coal from the longwall face, and allows the roof and overlying rock to collapse into the void left behind. This mining method was used in mines in counties over 119 figure 161. Final report effects of longwall mining on real property. Longwall mining overview introduction underground coal. Underground coal mining accounts for 33% of the coal production in the united states. The kazakhstanskaya mine has rights to develop the following coal seams. Pdf a novel longwall mining layout approach for extraction of.
The second section describes underground mining equipment, with particular focus on excavation machinery such as boomheaders, coal cutters, continuous miners and shearers. During the extraction process material is being mined out by longwall shearers. Determination of longwall mininginduced stress using the. Longwall mining and roomandpillar mining are the two basic methods of mining coal underground, with roomandpillar being the traditional method in the united states. Longwall mining method, concerns and issues caving methods.
The weight of bridging strata and strata that cantilevers over the destressed zone is shifted to adjacent gates, pillars, and abutments surrounding the longwall panel. In the shortwall mining method, the layout is similar to the longwall method except that the block of coal is not more than 100 metres wide. Shortwall mining, sublevel caving, block caving, problems with caving method, post mining activities learning assessment. This page was last edited on 15 january 2020, at 14. Content is available under creative commons attributionnoncommercialsharealike.
Longwall general layout top gate face dip direction bottom gate longwall mining method includes drivage of two long roadways in coal and joining them at the end by a perpendicular drivage forming a face. Longwall mining panelandpillar and roomandpillar bordandpillar mining are the two basic methods of mining coal underground, with roomandpillar being the traditional method. Introduction to longwall mining and subsidence mine subsidence. The continued growth of longwall mining without appropriate multipleseam planning may increase the cost and risk of mining. Two types of coalcutting machines are used for longwall mining. The longwall face is indicated by the number 8 in the diagram. The coal is collected on a conveyer and transported to the mines processing facilities. Unlike earlier longwall mining, the use of a conveyor belt parallel to the coal face forced the face to be developed along a straight line. Roomandpillar mining in low seams is generally less efficient than longwall mining because as much as 50% of coal is lost. Optimization of the mine design factors is arguably the primary means for controlling interactions between operations. The only other machinery used was an electric cutter to.
A longwall method that extracted coal mostly by hand was used from 1856 to 1954. Final report effects of longwall mining on real property value and the tax base of greene and washington counties, pennsylvania table of contents adobe acrobat format. Longwall bleeder and gob areas have long been one of the most challenging and uncertain areas in a ventilation model. Longwall is an underground mining method which has a high rate of production capacity and mechanization ability. It set of longwall mining equipment consists of a coal shear er mounted on convey or operating. Com 4 introduction the modern longwall mining method was first developed in the early 1970s when the first shield supports were introduced. In any underground mining activity, the in situ vertical and horizontal stresses that exist in the rock are disrupted and redistributed by the mining process. Although widely used in other countries, longwall mining. The longwall face equipment is established at the end of the panel that is remote from the main headings and coal is extracted within the panel as the longwall equipment moves towards the main headings.
Cut and fill, stull stoping, square set stoping caving methods. Definition of longwall mining a high extraction method of mining along the face of a predefined block of coal, referred to as a panel, while allowing the immediate roof to collapse upon advancement panel configuration panels generally range in size from 500 to 1,000 feet. Longwall systems underground mining komatsu mining corp. Extraction of the coal seam causes stress redistribution around the mined panel in longwall mining.450 943 1465 146 596 1209 680 482 1329 368 1215 1137 301 38 739 323 784 1358 452 1451 628 1473 644 779 404 280 1278 138 1482 376 364 490 495 586 1379 655 1427 359 919 1045 194 1080 296 1232 1014 303