Browsing by Subject "properties of rocks"

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Access status: Open Access ,
Charakterystyka zmian właściwości skał karbońskich w strefach tektoniki nieciągłej w Górnośląskim Zagłębiu Węglowym
(Wydawnictwa AGH, 2011) Bukowska, Mirosława; Ćmiel, Stanisław R.
Within fault zones in the USCB there can be noticed changes of values of numerous physical, chemical and technological parameters of coals and rocks surrounding beds, even at great depths. Secondary changes of some properties of rocks of carboniferous formation of the Upper Carboniferous within non-continuous zones are results of various processes including epigenetic ones resulting from rocks weathering and thermal modifications. Zones of tectonic dislocations become the routes of migration of water and gases containing oxygen and nitrogen in infiltration zones that are favorable to weathering processes, what is the result of rock mass unblocking. The knowledge of rocks properties in dislocation zones is essential because of existence of natural hazards in rock mass that result from exploitation as well as considering difficulties in maintenance of mine workings within such zones. Changes of some physical and chemical properties of coal and barren rocks with approaching to fault surface have been characterized on the basis of kłodnicki and bytomski faults. The characterized properties are as follows: uniaxial compression strength of rocks surrounding the bed 507 in the Bobrek-Centrum mine and bed 416 in the Wujek mine as well as micro-hardness and degree of coal fracturing. There are shown changes of sandstones consisting among others in decrease of compression strength in the vicinity of faults. The decrease equals to several hundred per cent in the distance of several meters from the fault surface. In comparison to surrounding rocks changes of qualitative parameters of coal including its micro-hardness, degree of fracturing and volumetric density occur at smaller distance from the fault surface what is the result of coals properties - their structure and texture. The micro-hardness decreases essentially within the fault surface and the degree of fracturing of each grain increases several times. In the article it is noticed that the issue of rocks destruction in fault zones and influence on natural hazards in a rock mass in the aspect of designing and conducting of safe and rational exploitation is not included straight in the executive regulations of the Geological and mining law.