Proceedings of the Rocscience International Conference (RIC 2023)

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Pit Slope Design in Weak Rocks: Experience from Sukinda Chromite Valley, India

Authors
Jayeeta Dey1, *, Sujit Roy1, Abdul Matin2
1SRK Mining Services (India) Pvt Ltd, Kolkata, India
2University of Calcutta, Kolkata, India
*Corresponding author. Email: jdey@srk.co.in
Corresponding Author
Jayeeta Dey
Available Online 8 November 2023.
DOI
10.2991/978-94-6463-258-3_72How to use a DOI?
Keywords
Weak rock; pit design; water management
Abstract

Sukinda chromite valley is the largest chromite deposit in India with six chromitite bands mined by several open pit mines. Host rock ultramafic sequence is weathered and altered to a thick profile of limonite that forms majority of the pit walls. The limonitic rockmass is massive, silt and clay rich and exhibits very low strength (~1-5 MPa), leading to shallow pit slopes and sterilization of ore below the designed pits. Geotechnical audit of several open pits indicated the potential of steepening the pit slopes. Conventional material characterization programme was found inadequate as undisturbed sampling is difficult in weak limonites. Extensive site characterization programme was implemented to resolve the issue. Geotechnical models were developed in Rocscience Slide 2, including FE groundwater models. Range of overall slope angle scenarios were evaluated to arrive at stable and optimal slope angles. Study indicates near surface monsoon water table significantly reduces the stability of pit walls. Horizontal drains were found to improve the stability and helped achieving FoS required for design acceptance. Optimal slope designs were implemented successfully in many open pits in Sukinda that extended the life of the mine significantly.

Copyright
© 2023 The Author(s)
Open Access
Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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Volume Title
Proceedings of the Rocscience International Conference (RIC 2023)
Series
Atlantis Highlights in Engineering
Publication Date
8 November 2023
ISBN
10.2991/978-94-6463-258-3_72
ISSN
2589-4943
DOI
10.2991/978-94-6463-258-3_72How to use a DOI?
Copyright
© 2023 The Author(s)
Open Access
Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

Cite this article

risenwbib
TY  - CONF
AU  - Jayeeta Dey
AU  - Sujit Roy
AU  - Abdul Matin
PY  - 2023
DA  - 2023/11/08
TI  - Pit Slope Design in Weak Rocks: Experience from Sukinda Chromite Valley, India
BT  - Proceedings of the Rocscience International Conference  (RIC 2023)
PB  - Atlantis Press
SP  - 783
EP  - 789
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6463-258-3_72
DO  - 10.2991/978-94-6463-258-3_72
ID  - Dey2023
ER  -