Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Determination of caved and water-conducting fractured zones of “two soft and one hard” unstable coal seam

Determination of caved and water-conducting fractured zones of “two soft and one hard” unstable... The height of the development of a caved zone (CZ) and a water-conducting fractured zone (WCFZ), hereinafter “CZ and WCFZ”, in mining of soft coal with a soft mine floor, hard mine roof and different thicknesses of the coal seam, hereinafter “two soft and one hard” unstable coal seam, is of interest in the long wall coal mining. An observation borehole was drilled above a coal seam with an average thickness of 4.0 m. By using borehole imagery technique and comparing the borehole images at different distances from the working face, the height of “CZ and WCFZ” at the working face is calculated under the condition of insufficient mining. Based on field observations, a 3D numerical model is developed under the condition of full mining, the height of CZ is calculated to be 14.4 m and the height of WCFZ calculated to be 67.0 m. The numerical model also shows changes in the vertical stresses in the overburden strata above the roof of the coal seams and it is related to the development of the “CZ and WCFZ”. At the same time, based on the key strata theory and multiple linear regression, the height of WCFZ in the working face of this case study is predicted to be 67.0 m and 64.8 m respectively, which is close to the numerical simulation results. At the same time, 30 groups of measured data are collected to analyze the main factors affecting the WCFZ, and the influence of different lithology characteristics of overburden strata on the WCFZ is mainly discussed. The results show that the height of WCFZ is hard–hard > hard–soft > soft–hard. The results provide important practical guidelines for the prevention and control of roof water hazards in coal mine thus improving the safety of mining. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png "Acta Geodaetica et Geophysica" Springer Journals

Determination of caved and water-conducting fractured zones of “two soft and one hard” unstable coal seam

"Acta Geodaetica et Geophysica" , Volume 55 (3) – Sep 25, 2020

Loading next page...
 
/lp/springer-journals/determination-of-caved-and-water-conducting-fractured-zones-of-two-l10QKM6C0P
Publisher
Springer Journals
Copyright
Copyright © Akadémiai Kiadó 2020
ISSN
2213-5812
eISSN
2213-5820
DOI
10.1007/s40328-020-00300-w
Publisher site
See Article on Publisher Site

Abstract

The height of the development of a caved zone (CZ) and a water-conducting fractured zone (WCFZ), hereinafter “CZ and WCFZ”, in mining of soft coal with a soft mine floor, hard mine roof and different thicknesses of the coal seam, hereinafter “two soft and one hard” unstable coal seam, is of interest in the long wall coal mining. An observation borehole was drilled above a coal seam with an average thickness of 4.0 m. By using borehole imagery technique and comparing the borehole images at different distances from the working face, the height of “CZ and WCFZ” at the working face is calculated under the condition of insufficient mining. Based on field observations, a 3D numerical model is developed under the condition of full mining, the height of CZ is calculated to be 14.4 m and the height of WCFZ calculated to be 67.0 m. The numerical model also shows changes in the vertical stresses in the overburden strata above the roof of the coal seams and it is related to the development of the “CZ and WCFZ”. At the same time, based on the key strata theory and multiple linear regression, the height of WCFZ in the working face of this case study is predicted to be 67.0 m and 64.8 m respectively, which is close to the numerical simulation results. At the same time, 30 groups of measured data are collected to analyze the main factors affecting the WCFZ, and the influence of different lithology characteristics of overburden strata on the WCFZ is mainly discussed. The results show that the height of WCFZ is hard–hard > hard–soft > soft–hard. The results provide important practical guidelines for the prevention and control of roof water hazards in coal mine thus improving the safety of mining.

Journal

"Acta Geodaetica et Geophysica"Springer Journals

Published: Sep 25, 2020

There are no references for this article.