Interactions of overburden failure zones due to multiple-seam mining

The longwall top coal caving (LTCC) method is an effective mining approach that originated in Europe, and has been widely and successfully used in China. ... Sui, W., Hang, Y., Ma, L. et al. Interactions of overburden failure zones due to multiple-seam mining using longwall caving. Bull Eng Geol Environ 74, 1019–1035 (2015). …

Theoretical equation of initial top-coal boundary in longwall top-coal

The theoretical equation of initial top-coal boundary (ITCB) is one of the fundamental problems of top-coal drawing law in longwall top-coal caving (LTCC) mining. The granular mechanical model of ITCB is established based on loose medium flow field theory. By analysing the stressed top-coal on ITCB along the section of coal …

Longwall top coal caving (LTCC) mining technologies with …

Longwall top coal caving (LTCC) mining technologies with roof softening by hydraulic fracturing method. V Klishin 1, S Nikitenko 1 and G Opruk 1. ... The paper discusses advanced top coal caving technologies for thick coal seams and addresses some issues of incomplete coal extraction, which can result in the environmental …

Improving the top coal recovery ratio in longwall top coal …

Reprints & Permissions. Read this article. The recovery ratio of longwall top coal caving (LTCC) technology is an important measure of its effectiveness. However, …

Methane control for mechanised longwall top-coal caving …

In China, mechanised longwall top-coal caving technology ... FU Q., and WU J.: 'DEM study of the drawing law in longwall top-coal caving mining', (eds. Heping Xie et al.), …

Improving the top coal recovery ratio in longwall top coal caving

The recovery ratio of longwall top coal caving (LTCC) technology is an important measure of its effectiveness. However, the recovery ratio of single-opening sequential caving technology in thick and extra-thick coal seams needs improvement. To address this, an independent cluster-group caving technology is proposed in this study.

Rockburst and Gas Outburst Forecasting using a Probabilistic …

The changing mining conditions during longwall top coal caving mining (LTCC) were extracted from a coupled numerical model to provide statistically sufficient data for probabilistic analysis. The complex interdependencies among abutment stress, pore pressure, the volume of total gas emission and incremental energy release rate, …

CDEM simulation of top‐coal caving

Longwall top coal caving (LTCC) mining is the most efficient method for thick and extra-thick coal seam extraction. It is extensively applied in western China. 1-5 As illustrated in Figure 1, the bottom coal is cut by the shearer, ...

A new cavability assessment for Longwall Top Coal Caving …

1. Introduction. Longwall Top Coal Caving (LTCC) can provide substantially less economic sensitivity and a reduced level of technical risk over other thick seam mining methods. 1 A reliable evaluation of LTCC's applicability at the feasibility stage of a new mining project is therefore of importance to the effective and productive extraction of …

Numerical modelling of anomalous microseismicity influenced …

Coal Mine Velenje produces 3.4 million tonnes of lignite per annum from the largest coal deposit in Slovenia. The multi-level longwall top coal mining method, referred to as the Velenje Mining Method (Jeromel et al., 2010), is used at Coal Mine Velenje to mine a coal seam which is up to 160 m thick in the centre of the coalfield.

Key technologies and equipment for a fully mechanized top-coal caving …

Thick and ultra-thick coal seams are main coal seams for high production rate and high efficiency in Chinese coal mines, which accounts for 44 % of the total minable coal reserve. A fully mechanized top-coal caving mining method is a main underground coal extraction method for ultra-thick coal seams. The coal extraction technologies for …

Case Study on Overburden Fracturing during Longwall Top Coal Caving

Longwall top coal caving (LTCC) is a highly efficient underground mining method that has recently been introduced and modified, and is now being used in underground coal mines in China. The major difference between LTCC and traditional longwall methods is that LTCC extracts caved coal from behind shields as well as from …

A particle-based numerical investigation on longwall top coal caving mining

Abstract and Figures. A 3D particle-based numerical approach to simulate the longwall top coal caving (LTCC) process was proposed, which for the first time the effect of continuous support advance ...

Monitoring and modelling of gas dynamics in multi-level longwall top …

The mining method used at Coal Mine Velenje is a combination of multi-level mining and longwall top coal caving (LTCC), as illustrated in Fig. 5. From the top to the bottom, the entire coal deposit is divided into a series of mining levels ranging from 10 to 20 m thick, mined in time-sequence with at least six months between the mining of each ...

Dynamic Random Arching in the Flow Field of Top-Coal Caving Mining …

The caving of top-coal in ultra-thick coal seam is a complicated process, and the drop-flow state will directly affect the recovery ratio of top-coal [21,22,23].Due to the different fragment dimensions of the top-coal and immediate roof rock, different fragment dimension of top-coal in the direction of top-coal thickness, combined with the …

Theoretical description of drawing body shape in an inclined …

Understanding the characteristics of drawing body shape is essential for optimization of drawing parameters in longwall top coal caving mining. In this study, both physical experiments and theoretical analysis are employed to investigate these characteristics and derive a theoretical equation for the drawing body shape along the …

Techno-Economic Feasibility of the Longwall Top Coal …

An extraction method for deep-seated thick seam deposits by underground mining with high resource recovery has remained a great challenge for Indian mining …

Monitoring strata behavior due to multi-slicing top coal caving

For studying the strata behavior due to multi-slicing top coal caving longwall mining along-the-strike direction in steeply dipping extra thick coal seams, the shield support pressures of the upper and lower slices of panel 37220 in Dongxia Coal Mine were monitored using the KJ513 dynamic monitoring system. The set up rooms adopted the ...

Energies | Free Full-Text | Roof Strata Behavior and Support …

The Longwall Top Coal Caving (LTCC) method has greatly improved the production of ultra-thick underground coal resources. However, face fall and support closure have been becoming highly frequent accidents at the working face, and seriously threaten the safety of miners. The key to avoiding these problems is to reveal the structural evolution of the …

A novel non‐pillar coal mining technology in longwall top …

Abstract. In longwall top coal caving (LTCC) mining methods, problems such as large deformations, loss of coal resources, and excavation relay out of balance …

Numerical simulation of realistic top coal caving intervals …

Longwall top coal caving (LTCC) mining consists of two processes: shearer cutting in front of a hydraulic support and top coal caving behind a hydraulic …

Experimental and numerical investigation on coal …

The primary process of the top coal caving mining is that conventional longwall mining with a cutting height 2–3 m is performed at the bottom of a thick seam, e.g., more than 5 m thick, followed by the …

A new cavability assessment criterion for Longwall Top Coal Caving

Longwall Top Coal Caving (LTCC) is a modified longwall mining method for efficient extraction of the thick coal seams. The major difference between LTCC and the traditional longwall method is the extraction of the caved coal from behind the shields as well as the sheared face (Fig. 1).The method has been widely implemented by the …

Investigation of the effect of caving height on the efficiency …

The longwall top coal caving (LTCC) production method, applied by forming a face in the horizontal thickness of the seam and also called horizontal section top coal caving, especially in studies originating from China, is widely used in the production of inclined and thick coal seams.

International Journal of Mining Science and Technology

The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106–110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.

A review of cavability evaluation in longwall top coal caving

A large number of studies on the applicability of Longwall Top Coal Caving into new mine sites have linked the success of its application to the geomechanical …

A particle-based numerical investigation on longwall top …

Abstract. A 3D particle-based numerical approach to simulate the longwall top coal caving (LTCC) process was proposed, which for the first time the effect of …

Caving mechanisms of loose top-coal in longwall top-coal …

Today, the top-coal caving longwall mining is the major mining method for thick seam coal mining in China. In the Datong coal district, the annual production is 1.5 …

Trial of small gateroad pillar in top coal caving longwall mining …

The top coal caving longwall mining method with two-entry panel development has long been practiced at Tashan Mine. A pillar 38–45 m wide was used between the two gateroads in order to reduce the overlapping of side abutment pressures generated by the mined-out panels on each side, isolate methane from the previous …

Monitoring and modelling of gas dynamics in multi-level longwall top …

Although gas emissions during mechanised conventional longwall mining have been extensively studied in the past few decades (Karacan et al., 2011, Lunarzewski, 1998, Noack, 1998), gas emission patterns around longwall top coal caving (LTCC) panels used in mining thick/ultra-thick coal seams are not very well understood. The …

Drawing mechanisms for top coal in longwall top coal caving …

Longwall top coal caving (LTCC) is a special type of mining method commonly used to extract coal seams thicker than 4.5 m (Wang et al. 2018a ). This …

Caving mechanisms of loose top-coal in longwall top-coal caving mining

Today, the top-coal caving longwall mining is the major mining method for thick seam coal mining in China. In the Datong coal district, the annual production is 1.5 million metric tons per panel. The top-coal caving longwall mining has attained outstanding achievements in coal mines with favorable conditions. It has also achieved …

Longwall Top Coal Caving (LTCC) technology

Yancoal introduced the Longwall Top Coal Caving (LTCC) mining technology to Australia at its Austar mine in 2006. Developed in China, top coal caving uses a modified long wall mining system. LTCC allows the excavation of thick coal seams of 5 to 12 metres at one pass of the longwall machine, generating high productivity and economic returns for ...

Theoretical equation of initial top-coal boundary in longwall top-coal …

Due to the unbalanced top coal drawing process, the recovery ratio is low, and the equipment stability is poor in the longwall top coal caving mining (LTCC) with an inclined seam. Aimed at these ...

to supply two complete longwall top coal caving …

The longwall top coal caving (LTCC) mining method to be employed at the Eynez East underground coal mine is a special type of longwall mining applicable to seams thicker than 6 meters (20 feet).

A review of cavability evaluation in longwall top coal caving

Longwall Top Coal Caving was initially developed in the former Soviet Union and France in the 1950s and 1960s. It was then applied in the former Yugoslavia, Hungary, Romania, the former Czechoslovakia and Turkey [4], [5], [6].The 'Soutirage' method which was developed in France in the 1960s is considered as the original form …

A Continuous Conversion Technology from Top Coal Caving …

Table 1 shows that the minimum thickness to be a thick seam is in the range of 3.0–4.8 m, the coal seam with a thickness over 3.5 m is considered as a thick coal seam in China. Based on the most advanced longwall mining technology, the coal seam with a thickness between 3.5 to 7 m is defined as the thick coal seam, and the coal seam …

Longwall top coal caving design for thick coal seam in very …

The amount of coal for the production panel must be high enough to cover the initial investment of the mechanized longwall system. Longwall top coal caving (LTCC) is a part of longwall mining that is applicable for thick coal seams. China is an important country, which has best practices of LTCC in terms of high production rates.

Comprehensive Study of Strata Movement Behavior in Mining a Longwall

The longwall top coal caving method with retreat mining is used for winning coal. The thickness of coal is 4.2 m, the coal cutting height by shearer is 2.8 m, and the top coal caving height is 1.4 m. Roof strata are naturally collapsed behind shields. The drum of the shear is 0.8 m meaning that the 0.8 m coal is cut for each web.

Longwall Top Coal Caving | Introduction | underground COAL

Longwall top coal caving (LTCC) is a special type of longwall mining applicable to very thick seams (greater than 4.5m) where good quality coal is being left because "conventional" longwall equipment has not yet been designed to operate successfully beyond around 5m mining height. It enables an increased recovery for only an …