Borehole GPR investigations from underground for mapping the extension of old working at a Pb-Zn Mine in Rajasthan, India

DOI

10.2991/rare-16.2016.82How to use a DOI?

Keywords

crosshole GPR; borehole GPR profiling; water-logged working; radar wave attenuation; radargram; conductive fluid; seepage; Pb-Zn mines

Abstract

Conventional GPR reflection surveys in base metal sulphide mines are sometimes marred by scattering due to heterogeneity or presence of disseminated sulphide minerals. Surface scanning in such areas have its own limitations as the depth of investigation is adversely influenced by the highly lossy medium. Alternatively, borehole GPR investigation from underground can be an efficient tool for sensing the proximity of old workings including cavities left over by past ore extraction. In the present study two borehole GPR techniques were used from underground to establish the boundary of old workings in a Pb-Zn mine. Crosshole transmission mode data from a stepped-frequency GPR was analysed to delineating the zone of influence created by ancient mining activity. Two parameters namely velocity and attenuation of radar waves were used to examine the intervening geological medium. Single-hole reflection survey was also carried out to scan the medium around the borehole. The result of crosshole GPR survey is a plot of radar wave attenuation along the horizontal plane of survey. The attenuation plot clearly delineated the zone affected by past mining activity; however cavity type features were not mapped. Even though exploratory drill holes showedevidences of old workings up to 250-260 m depthfrom the ground surface, the present borehole GPR investigation from an underground gallery at 298 m depth confirmed that old workings did not cross the horizontal plane of investigation

Copyright

© 2016, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - S. Nelliat
AU  - Babu B Butchi
AU  - P.C. Jha
AU  - Y.V. Sivaram
AU  - Verma SN
AU  - Dutta S
AU  - Jha A
PY  - 2016/11
DA  - 2016/11
TI  - Borehole GPR investigations from underground for mapping the extension of old working at a Pb-Zn Mine in Rajasthan, India
BT  - Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016)
PB  - Atlantis Press
SP  - 512
EP  - 517
SN  - 2352-5401
UR  - https://doi.org/10.2991/rare-16.2016.82
DO  - 10.2991/rare-16.2016.82
ID  - Nelliat2016/11
ER  -