STUDY OF SEISMIC SOURCE MECHANISMS IN MINES OF THE VERKHNEKAMSKOYE POTASH DEPOSIT
For over 13 years a routine seismic monitoring has been carried out at six of the mines in the worlds second largest potash deposit, the Verkhekamskoye, Perm region. Russia. The observed level of seismicity is rather low in the mines. On average about 1 -2 events with seismic energies from 100 J up to 50 kJ are recorded daily. The seismicity doesnt show any direct temporal and spatial correlation with mining operations. The sources are located within the areas which were mined in the past several years or up to several decades ago. We believe that the observed seismicity can be regarded as a source of information about the fracture processes in the mined out areas. This interpretation is important for safe mining, as the integrity of horizons above the excavations needs to be controlled to exclude possibility of flooding of the mine.An investigation of source mechanisms of seismic events was undertaken. The waveforms of the majority of events are rich in low frequency surface waves (0.5 - 2 Hz) which is explained by the proximity of both the sensors and the sources to the earths surface and consistent layered geology of the deposit. The standard inversion technique for surface waves was applied to the seismic monitoring data (64 largest events occurred in the mines Solikamsk-1, -2 and -3 in 2004). The analysis of both amplitude and phase properties of the obtained point sources (single forces and moment tensors) was done in terms of mechanisms which are possible in these mining conditions viz. shear and tensile failures in host rocks, rock falls in the excavations and pillar bursts. The application of the above technique points to rock falls and horizontal tensile failures as the most likely mechanisms for the majority of the events. These mechanisms produce synthetic surface waves which fit the observed ones quite well.The acquired experience of previously done and current studies of seismic sources in the mines of the Verkhnckamskoye potash deposit makes it possible to conclude that it is a rock fall that is the most probable mechanism of the local seismic events.
DMITRIY A.MALOVICHKO
Mining Institute, Ural branch of the Russian academy of sciences Perm 614007, Russia
国际会议
The 7th International Symposium on Rockburst and Seismicity in Mines(2009年第七届国际岩爆与微振动性学术研讨会)
大连
英文
387-398
2009-08-21（万方平台首次上网日期，不代表论文的发表时间）