<abstract xmlns="http://www.w3.org/1999/xhtml"><p> This study presents an innovative approach for determining the unconfined yield strength σ<sub>c</sub> during the excavation of coal from the earth’s crust by using an equipment that was developed for measuring the mechanical properties of bulk materials stored in silos. Highly productive excavation of coal with a hanging wall top caving leads to intensive deformations in the hanging wall and the broken coal can be considered as bulk material. In this research, the shear tester Johanson Hang-Up Indicizer was used to measure the unconfined yield strength of the tested samples, even though such a tester cannot produce stress-strain conditions similar to those occurring during the excavation. An attempt was made to estimate the real unconfined yield strength of broken coal deep under the surface through a combination of measured data and extrapolation.</p></abstract>

This study presents an innovative approach for determining the unconfined yield strength σc during the excavation of coal from the earth’s crust by using an equipment that was developed for measuring the mechanical properties of bulk materials stored in silos. Highly productive excavation of coal with a hanging wall top caving leads to intensive deformations in the hanging wall and the broken coal can be considered as bulk material. In this research, the shear tester Johanson Hang-Up Indicizer was used to measure the unconfined yield strength of the tested samples, even though such a tester cannot produce stress-strain conditions similar to those occurring during the excavation. An attempt was made to estimate the real unconfined yield strength of broken coal deep under the surface through a combination of measured data and extrapolation.

Estimating the unconfined yield strength of coal in the case of longwall coal mining with hanging wall top caving

University of Ljubljana, Faculty of Natural Sciences and Engineering, Aškerčeva 12, 1000 Ljubljana,

Materials and Geoenvironment

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

This study presents an innovative approach for determining the unconfined yield strength σc during the excavation of coal from the earth’s crust by using an...

Estimating the unconfined yield strength of coal in the case of longwall coal mining with hanging wall top caving

Published Online: Oct 26, 2016

Page range: 73 - 80

Received: Apr 08, 2016

Accepted: May 03, 2016

DOI: https://doi.org/10.1515/rmzmag-2016-0006

Keywords
unconfined yield strength, coal, Johanson Hang-Up Indicizer

© 2016

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Estimating the unconfined yield strength of coal in the case of longwall coal mining with hanging wall top caving

Published Online: Oct 26, 2016

Page range: 73 - 80

Received: Apr 08, 2016

Accepted: May 03, 2016

DOI: https://doi.org/10.1515/rmzmag-2016-0006

Keywordsunconfined yield strength, coal, Johanson Hang-Up Indicizer

© 2016

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
unconfined yield strength, coal, Johanson Hang-Up Indicizer