Vibrations generated by quarry blasting are the most intensivemanifestation of technical seismicity. Comparative measurements ofvibrations from blasting generated in open-pit mines were performedin the Jeronym Mine near ?istá (Czech Republic). A detailedevaluation of vibrations on underground spaces is very important herebecause this mine is a significant heritage site of medieval tin mining.The distance between the nearest feldspathic quarry named Krásnoand the Jeronym Mine is 4.7 km east, Vítkov quarries (granite)is located north in the distance of 6.3 km. Maximum values fromthe nearest quarry Krásno are usually within the range of10-3 – 10-2 mm.s-1. Prevailing frequency range of recorded waves is1 - 6 Hz for both quarries.To qualify seismic loading of mine, one seismic station was located onthe surface, the second one in the mine at a depth of about 30 m.Power spectra could be used for distinguishing, but the difference inspectra shapes is rather evident. Especially the difference is mostexplicit for the frequency range 70 - 100 Hz between power spectra ofsurface and underground records. Fitted trends were calculated for thementioned frequency range of power spectra. Spectral time-frequencydiagrams were also defined.
展开▼
