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Browsing by Subject "preconditioning"

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  • thumbnail.journal.alt
    Item type:Thesis, Access status: Restricted ,
    Estymacja gęstości jako problem odwrotny
    (Data obrony: 2016-07-19) Stawiski, Marcin
    Wydział Matematyki Stosowanej
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Zagrożenie tąpaniami podczas eksploatacji ściany 8 w pokładzie 510 warstwa dolna w KWK »Bobrek-Centrum«
    (Wydawnictwa AGH, 2009) Jankowski, Janusz; Pawszok, Bronisław
    The article presents the formation of the real rockburst hazard condition and scope of applied active rockburst prevention on the longwall 8 located in the north-eastern part of the mining Area »Bytom-Centrum I«, »Bobrek-Centrum« Colliery, in the safety pillar of the town Bytom. The seam 510 in the panel of longwall 8 occurs at the depth of 550-730 m, with the inclination 5-110 towards south-west; the seam thickness amounts to: 9.0-9.7 m. During longwall 8 mining in the seam 510 occurred periods with enhanced seismic activity. On account of the rockbust hazard formation, two essentially differing periods of longwall 8 mining can be distinguished: from longwall operation start till the end of September 2007 and from October 2007 till the present moment, i.e. till 7 December 2008. The finally worked out active rockburst prevention in the form of shock and camouflet blasting in the seam, torpedo blasting in the roof and high-pressure water injection into the seam coal solid as well as technical limitations (daily advance up to 2.1 m and longwall height up to 2.3 m) allowed to continue longwall 8 mining in the seam 510. In consequence the majority of strong tremors was provoked by active rockburst prevention, mainly camouflet blasting as well as camouflet and preconditioning. High efficiency indicates also the method of high-pressure water injection into the seam coal solid. The long period (up to 25 hours) of maintaining of water pressure, knocks, destressing and tremors as well as seismoacoustics emission increase, occurring during the water injection on longwall 8 in the seam 510, prove the efficiency of this method.