Caving Underground Mining Methods longwall Sublevel caving…

5 Longwall Stoping Longwall stoping is applicable to bedded deposits of uniform shape limited thickness and large horizontal extension a coal seam a potash layer or the reef the bed of quartz pebbles exploited by gold mines in South Africa It is a caving method particularly well adapted to relatively flat lying thin planar deposits or horizontal

Longwall Top Coal Caving Introduction underground COAL

Longwall Top Coal Caving Longwall top coal caving LTCC is a special type of longwall mining applicable to very thick seams greater than 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

Numerical modelling of anomalous microseismicity

Longwall top coal caving LTCC is one of the main mining methods for high yield and high efficiency in extremely thick coal seam in China Alehossein and Poulsen 2010; Cao et al 2019; Wu et al

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

In longwall top coal caving LTCC mining methods problems such as large deformations loss of coal resources and excavation relay out of balance are often encountered with the increased production in single mining panels To address these problems a novel non‐pillar coal mining technology in LTCC was used based on the equilibrium mining theory

Effect of Key Parameters on Top Coal First Caving and Roof

The first caving of top coal and the first weighting of roof strata in Longwall Top Coal Caving LTCC mining were analyzed in a parametric study by using a discontinuum modeling technique with

An acoustic wave method for evaluating the effectiveness of

The advanced deep hole blasting ADHB is commonly used to improve the fragmentation of thick hard top coal in longwall top coal caving LTCC mining This paper presents an acoustic method to

Improving coal recovery from longwall top coal caving

Longwall top coal caving LTCC is a relatively new method of mining thick coal seams that is currently achieving high productivity and efficiency in application particularly in China The

Caving mechanisms of loose top coal in longwall top coal caving

The top coal caving longwall mining was successfully put on trials in Yangquan Mining Bureau in 1988 and Lu an Mining Bureau in 1989 At the same time research on the top coal caving mining in steeply inclined thick coal seams began with good results [5]

CDEM simulation of top‐coal caving characteristics under

Traditionally longwall top coal caving LTCC panels adopt the single‐window drawing mode and their drawing efficiency is relatively low The synchronous multi‐window drawing SMWD mode is a remarkable approach to resolve the incompatibility between shearer coal mining and top‐coal drawing The present paper analyzes the caving characteristics of top

Strata movement and shield pressure analysis at Tongxin longwall top

Roof strata movement and shield pressure are two important factors that affect the production and efficiency of longwall top coal caving LTCC method in extra thick coal seams The performances of these two aspects can be very different from one mine to another depending on the roof strata conditions In this paper the geological conditions of the LTCC 8202 panel at

A new cavability assessment for Longwall Top Coal Caving

This paper presents a new criterion for assessing top coal cavability in Longwall Top Coal Caving mining technology Top coal Cavability Index TCI criterion was developed through a parametric

Front Stress Distribution Under the Impact of Cutting

Cutting Height to Caving Height Ratio in Extra thick Longwall Top Coal Caving Technology Bui MANH TUNG1 Nguyen VAN QUANG1 Nguyen PHI HUNG1 Vo NGOC DUNG2 Do HOANG HIEP3 Abstract The extraction with higher cutting height for extra thick seam is the new research orientation in longwall caving technology Due to

Improving the top coal recovery ratio in longwall top coal caving

ABSTRACT 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 Four numerical

Evolution of mining‐induced stress in fully

This review details the state of the art in research on top coal drawing mechanisms in Longwall top coal caving LTCC by examining the relevant literature over the last two decades It starts with an introduction of the brief history and basic procedures of LTCC The framework of research on the drawing mechanism basic concepts and some theoretical

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 this production method in addition to the top coal losses that occur behind the

A study into the feasibility of application of

The Broadmeadow mine was started using a longwall to extract coal at m 15 ft leaving the top section of the seam to fall into the gob The adjacent open cut mine has been mining the full seam section for more than 30 years investigations and evaluations were made into the Top Coal Caving method and its suitability for the operation

A particle based numerical investigation on longwall top coal caving

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 and the face end

Caving mechanisms of loose top coal in longwall top coal caving

Longwall Top Coal Caving LTCC is considered one of the most efficient methods for mining thick coal seams Compared to other thick seam mining methods LTCC can offer significantly reduced

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 Chinese coal industry with

MINERAL MINING TECHNOLOGY Prefeasibility

Abstract—Longwall Top Coal Caving LTCC a relatively newer technology in India is an underground mining method developed for thick seam extraction Various factors and systematic approaches

Study on gob side entry retaining in fully

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 In this production method in addition to the top coal

3D numerical modeling of longwall mining with top coal caving

Longwall top coal caving mechanisms and cavability optimization with hydraulic fracturing are analysed in this study Based on the geological and geotechnical conditions of the Dongzhouyao coal

Numerical and theoretical investigations of the effect of the

Discrete element calculations of the top coal drawing process for different gangue coal density ratios were conducted to investigate the effect of the gangue coal density ratio on the drawing mechanism in longwall top coal caving The effects were analyzed for the drawing body the top coal boundary and the recovery of top coal The results show that for

[PDF] Numerical modeling of longwall top coal caving

Thar Coalfield in Pakistan is the largest reserve of lignite coal in the country which is outlined by thick coal seams The preferred mining method for these thick coal seams is the Longwall Top Coal Caving LTCC The connection of both the top coal caving and its compactness are still rare; therefore the capability of top coal caving mechanism is the most