Time-lapse seismic tomography of an underground mining zone

Zewei Wang, Xibing Li, Dapeng Zhao, Xueyi Shang, Longjun Dong

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

In this study, we determined P-wave tomographic images of the Yongshaba deposit, an underground mining zone in Guizhou Province, China, by inverting arrival-time data of micro-seismic events and blasts recorded by a passive seismic array consisting of 28 sensors during January to April 2014 using an event location technique and a travel-time tomography method that can handle complex seismic discontinuities. The damping parameter used in the damped least-squares method is determined with the help of trade-off curve. To reveal internal P-wave velocity changes of the study area under severe mining activities, a time-lapse data partition scheme is used. To assess the human influence on the underground structure, we introduce a parameter to measure the relative velocity changes in different periods. The resolution of the tomographic images and the robustness of the obtained features are examined by conducting a series of checkerboard resolution tests and a restoring resolution test. Our tomographic results obtained from the entire data set reveal a prominent low-velocity (low-V) zone and many obvious high-velocity (high-V) zones. These features match well with the geological setting and the excavation plan carried out in the mine, according to in-site surveys. The low-V zone may reflect empty volumes, stress releases and rock breaking and cracking caused by mining activities, whereas the high-V zones are probably the consequences of local stress concentrations caused by regional stress redistribution. The time-lapse tomographic images may reveal the process of stress concentrations caused by rock breaking due to the continuing excavations in the entire observation period, indicating that the mining activities influenced the rock property and caused complex changes of the underground structure.

Original languageEnglish
Pages (from-to)136-149
Number of pages14
JournalInternational Journal of Rock Mechanics and Mining Sciences
Volume107
DOIs
Publication statusPublished - 2018 Jul

Keywords

  • Induced seismicity
  • Rock breaking
  • Seismic tomography
  • Seismic velocity
  • Stress redistribution

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology

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