In some instances, extensive room-and-pillar workings can collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may o...

Roof bolting is the most popular type of support for underground mines’ workings. However, in Polish coal mines it used only as a supplementary support. To raise effectiveness and economic score horizontal development works, JSW (Jastrzębska Spółka Węglowa) started project to introduce independent rock its mines. The key element monitoring mine workings supported with roof bolting, appropriate ...

Rock bursts are often encountered in coal mines worldwide [...]

In this study, laboratory experiments are conducted to investigate the rapid decompression and desorption induced energetic failure in coal using a shock tube apparatus. Coal specimens are recovered from Colorado at a depth of 610 m. The coal specimens are saturated with the strong sorbing gas CO2 for a certain period and then the rupture disc is suddenly broken on top of the shock tube to gene...

Original scientific paper Laboratory tests were conducted to study coal spontaneous combustion at low-temperature (30 ÷ 200 °C) in the air of reduced oxygen (10 ÷ 21 %) and low methane concentrations (0 ÷ 3 %). The production of carbon monoxide in coal spontaneous combustion was analysed. The test results show that both oxygen and methane concentrations affect coal spontaneous combustion. At gi...