Geological and geotechnical aspects of underground coal mining …
Longwall mining is the most common of the underground coal mining methods used in Australia. It suits sites where coal seams are thicker, wide and have a consistent coal profile with gentle dip. In longwall mining, large rectangular sections of coal are identified and removed in one continuous operation (Trueman et al. 2009). Basically, …
Automation in U.S. longwall coal mining: A state-of …
A novel no-pillar longwall mining method (NPLM) by roof cutting technology (RCT) was proposed in China, it can mitigate mining damage by increasing the volume …
Longwall automation: Delivering enabling technology to …
Longwall coal mining process. Longwall coal mining is a full extraction underground mining method that involves the removal of coal in large blocks or panels using a mechanised shearer. The coal panel is typically 200–450 m wide and can be up to five kilometres in length. The mechanical shearer is mounted on a shearer pan and rails …
(PDF) LONGWALL MINING SYNOPSIS
In principle, longwall mining is quite simple a coalbed is blocked out into a panel a veraging. nearly 800 f t (244m) in width, 7000 feet (2100 m) in length, and 7 feet (2.1m) in height, by ...
Shield-Roof Interaction in Longwall Panels: Insights from
The shield-roof interaction as mining proceeds in longwall panels remains unclear, hindering the further increase of longwall productivity. To uncover the mechanisms of shield-roof interaction, using our self-developed Status of Shield and Roof IntelliSense (SSRI) system, we investigated the effects of idle time, retreating rate, setting pressure, …
Introduction to Longwall Mining and Subsidence ver2
Mine Subsidence Engineering Consultants Level 1 / 228 Victoria Avenue – Chatswood – NSW 2067 PO Box 3047 – Willoughby North – NSW 2068 Tel. (02) 9413 3777 Fax. (02) 9413 3822 Email: enquiries@minesubsidence. Revision A …
Longwall method | coal mining | Britannica
In the longwall system the ore body is divided into rectangular panels or blocks. In each panel two or more parallel drifts (for ventilation and ore transport) are driven along the opposite long sides to provide access, and at the end of the…. The other principal method of modern mining, longwall mining, had been introduced as early as the ...
Conveyor pan coupling assembly
An improved coupler assembly for pans in a longwall mining conveyor system for handling coal or the like is provided. The assembly includes a dog-bone coupler having notched ends. A first end of the c ... 40b hold the leg 34 and, thus, the retainer 30 securely in place (FIGS. 4a and 4b). The leg 24 can be manually released from the slot …
Examination of Design and Operation Practices for …
Throughout the history of longwall mining, the design of the roof support system has been critical to the success of the mining operation. Early forms of longwall mining used wood props for face support and packwalls made from roof and floor rock to control caving of the imme diate roof (I).2 These systems were replaced by powered
Automation in U.S. longwall coal mining: A state-of …
Although fully automated, plow longwall never caught on in the U.S. and U.S. has little contribution in the development of automated plow longwall mining, and due to …
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Modern Longwall Mining
The shortest of its 11 longwall faces is now 1,100 ft, with the exception of the company's Buchanan mine in ia, which is running 700 ft due to geological conditions. All of the CONSOL Energy longwall faces are high-voltage state-of-the-art units with electronic controls and controlled start technology (CST) drives.
longwall mining dog leg
Longwall Mining - SlideShare. Face monitoring– Strata monitoring • Leg Pressures • Leg Closures • Face Convergence PRESSURE SURVEY Continuous Pressure Recorder in Mid Face of a Longwall Panel 40 Yield Pressure 35 30 PRESSURE (M pa) 25 Setting Pressure 20 15 33.6 39.3 56.2 74.1 95.4 111 119 141 163 180 198 220 237 259
Longwall Mining Overview | Introduction
Overview. In the method of secondary extraction known as longwall mining a relatively long mining face (typically in the range 100 to 300m but may be longer) is created by …
Numerical modelling approach for estimation of a yield zone …
In the Longwall mining method, the coal face is being supported with two-legged or four-legged shield supports which improve better roof control between the face and canopy tip. The development of ...
Avoiding And Correcting Problems | Longwall
Face Alignment and Creep. Face alignment, creep and face angle (relative position between main gate and tail gate location, which controls creep) are usually corrected by making straightening cuts or fly cuts working to a string line and carried out at the discretion of the longwall Supervisor. The decision is generally based on experience of ...
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4 LEG SUPPORT – Mining Science and Technology
This type of shield has two sets of legs inclined forward into the canopy and the other two inclined backwards and connected to the goaf shield. ... Longwall Mining (41) Overview (6) Equipment (17) Shearer (8) Powered Supports (3) Ventilation (3) Change Out (7) Ground Control (8) Bord & Pillar (15) Method (7)
LONGWALL MINING SUCCESS STORY
The longwall face at Yalevskogo mine is equipped with customized two-leg roof supports, each with a width of 1.75 meters and sup-port capacity of 725 tonnes. …
A new method for improving coal wall stability in longwall mining …
To propose a support stiffness based method for improving the stability of coal wall, static stiffness of the support and fracture development of the coal wall are monitored during retraction period of a panel in the second coal mine of Zhaogu coalfield. It is revealed that the range of support stiffness falls between 50 and 450 MN/m. In face …
Dynamics of Hydraulic Leg of Powered Longwall Support
Abstract. The designs of single- and double-telescopic hydraulic legs are analyzed, and the stand tests are carried out under dynamic loading in conformity with the requirements of European standards. The choice of facilities ensuring the reliable operation of powered support under different loading conditions is substantiated.
Design Considerations for the Next Generation of …
Reviewing the 25 year history of the use of the shield support for longwall mining in the United States, it is clear that the shield had a major role in making longwall mining the most productive ... In 1997, 63 of the 65 longwall faces in the U.S. were two-leg shield systems, compared to only 53 pct in 1985. Larger size hydraulic cylinders ...
Modelling of Longwall Mining-Induced Strata Permeability Change
Longwall mining in coal seams is an underground mining technique where a tabular block (longwall panel) of coal with a typical length of 1.5–3 km, typical width of 250–300 m and typical height of 3–4.5 m is extracted. Two pairs of roadways are first driven around the outside of the panel within the coal seam for access.
(PDF) Dynamics control of powered hydraulic roof …
The paper describes a case study of the safety hydraulic system damage in the working of a longwall in a Polish coal mine. The safety elements are a component of the powered roof supports which ...
Principles of Longwall Mining | |
This video provides a basic description of the longwall mining method for extracting coal underground. It includes an explanation of the different products/key components of a …
Longwall mining
Energy. Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 1-2 m thick). The longwall "panel" (the block of coal that is being mined) is typically 3-4 km long and 250-400 m wide. Longwall mining produced 176 million tons of coal in 2007, about 15 percent of total U.S. production.
Design of an Optimum Longwall Face for Improved Ground …
This paper presents a critical review of the various approaches for the selection of the optimum length of longwall face considering ground control and cost parameters. Various factors affecting the efficacy of roof control and their impact on the productivity of a mechanized longwall face have been identified. The outcome of the …
Advancing and Retreating Longwalls | Introduction
Advancing and Retreating Longwalls. Longwalls can be operated in two ways, referred to as "advancing" or "retreating" faces or frequently simply as advance or retreat longwalls. Advancing Longwalls. Retreating Longwalls. Comparison …
Top ten longwall problems
Latest Developments in Longwall Mining Technology
WEBOnly gate-end shields sometimes have two additional legs to cover the longer canopy, which is necessary because of the widths of the high-capacity head and tail drives of the …
Numerical analysis of a longwall mining cycle and …
Longwall mining is one of the two most popular mining methods of underground coal mining, the other being room and pillar (or bord-and-pillar) mining. The basic principles of longwall mining involves a coal bed being selected and blocked out into a panel ( Fig. 1 ) averaging nearly 100–350 m in width, 1–4 km in length, and about 2–4 …
