Perpustakaan Digital ITB
2019 Cover - Wahyudi Widyatmoko P.pdf
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PUBLIC Devi Septia Nurul
2019 Editorial Board - Wahyudi Widyatmoko P.pdf)u
PUBLIC Devi Septia Nurul
2019 Table Content - Wahyudi Widyatmoko P.pdf?
PUBLIC Devi Septia Nurul
2019 Paper - Wahyudi Widyatmoko P.pdf
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PUBLIC Devi Septia Nurul
Field investigation using Ground-Penetrating Radar (GPR) and Induced Polarization (IP) techniques has been
conducted in Bangka Island to monitor the stability of borehole after Borehole Mining (BHM) operation. This
BHM operation resulted a cavity forming in the borehole due to extraction of the alluvial tin layer. If the
overburden over the extracted layer cannot hold the stability of the borehole, the cavity formed in the hole can
reach the surface. Based on field observations, precisely in the Air Nudur Block (South Bangka Regency) and Air
Gumuruh Block (West Bangka Regency), cavities that formed on the surface can occur within a span time of a few
hours to several days after extraction of alluvial tin ore in the BHM hole is finished and the drill cased steel is
removed. We deployed GPR system with 100 MHz shielded antenna before and after BHM mining operation and
time domain IP system with 1.5 m electrode spacing conducted after BHM. Our research results show that both
GPR and IP techniques supported with numerical modeling reveal an overburden slide and subsidence in the
BHM bore