Techno-Economic Feasibility of the Longwall Top Coal Caving Method Based on the FTCD Index: A Parametric Case Study in India

An extraction method for deep-seated thick seam deposits by underground mining with high resource recovery has remained a great challenge for Indian mining engineers, whereas the longwall top coal caving (LTCC) method has evolved as an effective method for various geo mining conditions in China and other counties. The percentage of top coal recovery (TCR) plays a predominant role in determining the feasibility of LTCC, which relies on the First Top Coal Caving Distance (FTCD). In this paper, the critical geotechnical parameters are identified, numerically simulated, and statistically analyzed, and the FTCD for Indian geo-mining conditions is developed and validated. A financial assessment is conducted, considering 70% top coal recovery at 85% performance level, cost of production escalated by 20% and fall in coal grade by two grades. The internal rate of return (IRR) for LTCC is 30.24% as per the sensitivity analysis where it is only 18% in single pass longwall method. This study contributes to evaluating both the technical and economic feasibility of introducing LTCC in Indian geo-mining conditions.

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Study on Controlling Parameters and Technological Optimization of Strip Longwall Top Coal Caving in Thick Coal Seams

Inżynieria Mineralna ◽

10.29227/im-2020-02-14 ◽

2020 ◽

Vol 1 (2) ◽

Author(s):

Bui MANH TUNG ◽

Le TIEN DUNG ◽

Liu CHANG YOU ◽

Pham VAN CHUNG

Keyword(s):

Recovery Rate ◽

Technological Parameters ◽

Coal Seams ◽

Efficient Operation ◽

Coal Recovery ◽

Mining Conditions ◽

Face Length ◽

Longwall Top Coal Caving ◽

Cutting Height ◽

Selection Of

Based on the geological and mining conditions of face 3107 at Liang Baoshi coal mine, China, the numerical programs FLAC3D 2.10 and PFC2D 2.10 were used to analyze the parameters controlling the failure, caving and the coal recovery rate in Strip Longwall Top Coal Caving (SLTCC). The analyzed parameters are face length in dip direction, mining height, the span of coal caving, and sequence of coal drawing. The results show that the application of SLTCC for a limited face length is not favourable to coal failure, and it increases top coal loss. A sound engineering selection of technological parameters is therefore important to efficient mining in thick coal seams. The numerical results show that a face design of 3 m of cutting height, 0.8 m of caving span, and alternate drawing sequence results in high coal recovery rate, simple mining tasks, and efficient operation of face equipment.

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Occurrence of Linear Discontinuous Deformations in Upper Silesia (Poland) in Conditions of Intensive Mining Extraction—Case Study

Energies ◽

10.3390/en13081897 ◽

2020 ◽

Vol 13 (8) ◽

pp. 1897

Author(s):

Piotr Strzałkowski ◽

Katarzyna Szafulera

Keyword(s):

Rock Mass ◽

Underground Mining ◽

Building Structures ◽

Tectonic Structure ◽

Mining Operations ◽

Mining Areas ◽

Tectonic Faults ◽

Mining Conditions ◽

The Subject

Currently, linear discontinuous deformations in mining areas are an important issue, both due to the frequency of their occurrence and the threat they pose to general safety. This paper presents a case study of an occurrence of such a deformation. The analyses of the geological and mining conditions, as well as the conducted calculations presented herein, indicate that the cause of the deformation was the occurrence of high-value horizontal tensile strains. It was triggered by mining exploitation carried out with caving in three seams at depths between 200 and 545 m. An additional factor conductive to the creation of the deformation was the tectonic structure of the rock mass. The subject matter of the paper is significant given the growing number of discontinuous linear deformations occurring on the surface due to underground mining—even if the mining was conducted at great depths. They were formed as a result of intensive underground mining operations and the occurrence of high-value deformations. These deformations were particularly dangerous to building structures on the surface, which were often damaged. For this reason, it was worthwhile to make arrangements regarding the correlation between the occurrence of the deformations and the values and the distribution of continuous deformations caused by underground extraction, as well as the existence of tectonic faults.

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The Nature of Mining-Induced Horizontal Displacement of Surface on the Example of Several Coal Mines

Archives of Mining Sciences ◽

10.2478/amsc-2014-0067 ◽

2014 ◽

Vol 59 (4) ◽

pp. 971-986 ◽

Cited By ~ 3

Author(s):

Krzysztof Tajduś

Keyword(s):

Underground Mining ◽

Mining Industry ◽

Horizontal Displacement ◽

Surface Slope ◽

Proportionality Coefficient ◽

Model Studies ◽

Displacement Vectors ◽

Mining Conditions ◽

Design Projects ◽

Academy Of Sciences

Abstract The paper presents the analysis of the phenomenon of horizontal displacement of surface induced by underground mining exploitation. In the initial part, the basic theories describing horizontal displacement are discussed, followed by three illustrative examples of underground exploitation in varied mining conditions. It is argued that center of gravity (COG) method presented in the paper, hypothesis of Awierszyn and model studies carried out in Strata Mechanics Research Institute of the Polish Academy of Sciences indicate the proportionality between vectors of horizontal displacement and the vector of surface slope. The differences practically relate to the value of proportionality coefficient B, whose estimated values in currently realized design projects for mining industry range between 0.23r to 0.42r for deep exploitations, whereas in the present article the values of 0.33r and 0.47r were obtained for two instances of shallow exploitation. Furthermore, observations on changes of horizontal displacement vectors with face advancement indicated the possibility of existence of COG zones above the mined-out field, which proved the conclusions of hitherto carried out research studies (Tajduś 2013).

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