<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Methane and coal dust explosions are among the most common causes of disasters in hard coal mining. Therefore, it is important for occupational safety in hard coal mines operating under methane and coal dust explosion hazards to identify possible ignition sources, whether due to natural or technical factors. One technical source of ignition can be mechanical sparks generated during operation of mechanical equipment and high surface temperatures of equipment components during operation. This paper presents the methodology and results of thermal imaging and strength testing of roadway support elements under dynamic loading. The goal of the tests was to identify the potential explosive atmosphere ignition sources during the operation of the support under the conditions of rock bursts. The scope of testing encompassed the temperature measurements by means of thermal camera of friction prop and yielding support frame sliding joint elements at yield under dynamic impact loading (simulating a burst). Significant joint element heating and mechanical sparking was observed during the testing of arching yielding support frame sliding joints and straight friction prop joints as a result of friction at yield. Some of the aspects defined in standard PN-EN ISO80079-36:2016 include the maximum temperature T max =150°C for a surface that can accumulate a layer of coal dust. Tests of the friction joints have shown that during impact loading, numerous mechanical sparks are produced at the friction joints of sections of the steel prop, with the surface temperature of the sections starting from 169.6°C and reaching up to 234.1°C. During tests it was also to determined emissivites of the tested sliding joints constructed from V29-V32 secrions depending on corrosion products which consist in range 0.842–0.873. Such a high temperature can initiate an explosive mixture consisting of methane, air and coal dust.</p>
</abstract>

Methane and coal dust explosions are among the most common causes of disasters in hard coal mining. Therefore, it is important for occupational safety in hard coal mines operating under methane and coal dust explosion hazards to identify possible ignition sources, whether due to natural or technical factors. One technical source of ignition can be mechanical sparks generated during operation of mechanical equipment and high surface temperatures of equipment components during operation. This paper presents the methodology and results of thermal imaging and strength testing of roadway support elements under dynamic loading. The goal of the tests was to identify the potential explosive atmosphere ignition sources during the operation of the support under the conditions of rock bursts. The scope of testing encompassed the temperature measurements by means of thermal camera of friction prop and yielding support frame sliding joint elements at yield under dynamic impact loading (simulating a burst). Significant joint element heating and mechanical sparking was observed during the testing of arching yielding support frame sliding joints and straight friction prop joints as a result of friction at yield. Some of the aspects defined in standard PN-EN ISO80079-36:2016 include the maximum temperature T max =150°C for a surface that can accumulate a layer of coal dust. Tests of the friction joints have shown that during impact loading, numerous mechanical sparks are produced at the friction joints of sections of the steel prop, with the surface temperature of the sections starting from 169.6°C and reaching up to 234.1°C. During tests it was also to determined emissivites of the tested sliding joints constructed from V29-V32 secrions depending on corrosion products which consist in range 0.842–0.873. Such a high temperature can initiate an explosive mixture consisting of methane, air and coal dust.

Safety of Steel Arch Support Operation During Rock Bursts Under Explosive Atmosphere Conditions

Studia Geotechnica et Mechanica

This work is licensed under the Creative Commons Attribution 4.0 International License.

Methane and coal dust explosions are among the most common causes of disasters in hard coal mining. Therefore, it is important for occupational safety in hard...

Test no.	v_p, m/s	z, m	E_c, J	N_d, kN	T_max, °C
1	2.05	140	25,556	183	169.6
2		110	23,387	213
3		95	33,256	235
4	2.45	155	33,256	215	175.5
5		160	33,617	210
6		150	45,293	219
7	2.79	230	45,293	197	234.1
8		205	43,485	212
9		205	43,485	212
			Average	211
			Standard deviation	14

Safety of Steel Arch Support Operation During Rock Bursts Under Explosive Atmosphere Conditions

Article Category: Research Article

Published Online: Mar 17, 2023

Page range: 144 - 157

Received: Sep 24, 2021

Accepted: Jan 05, 2023

DOI: https://doi.org/10.2478/sgem-2023-0004

Keywords
arching support sliding joints, straight prop sliding joints, dynamic load capacity, kinetic coefficient of friction, thermal imaging

© 2023 Andrzej Pytlik et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

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Figure 11

Result compilation of SV32t straight sliding joint tests under dynamic loading.

Safety of Steel Arch Support Operation During Rock Bursts Under Explosive Atmosphere Conditions

Article Category: Research Article

Published Online: Mar 17, 2023

Page range: 144 - 157

Received: Sep 24, 2021

Accepted: Jan 05, 2023

DOI: https://doi.org/10.2478/sgem-2023-0004

Keywordsarching support sliding joints, straight prop sliding joints, dynamic load capacity, kinetic coefficient of friction, thermal imaging

© 2023 Andrzej Pytlik et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Result compilation of SV32t straight sliding joint tests under dynamic loading.

Keywords
arching support sliding joints, straight prop sliding joints, dynamic load capacity, kinetic coefficient of friction, thermal imaging