Slope Stability Analysis of Itakpe Iron Ore Mine, Itakpe, Nigeria

Rasheed A. Adebimpe, Jide Muili Akande, Chinwuba Arum

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The Federal Polytechnic,Ado-Ekiti, Dept. of Mineral Resources Engineering.

DOI: 10.4236/eng.2011.36072                

Abstract

The slope stability of the Itakpe Iron Ore Mine has been carried out using computer software, ROCKPACK III. One hundred and twenty three dip and dip direction values were obtained using compass clinometer. The Itakpe Iron Ore Mine was divided into four benches; 241 - 258 m, 263 - 275 m, 276 - 286 m and 308 - 312 m. Joints along the discontinuities were mapped. The data obtained were analyzed using ROCKPACK III. The results indicate that the discontinuities within the critical zone are potentially unstable and can lead to planar failure. The Markland test carried out for wedge failure indicates that the intersection of the discontinuities does not fall within the critical zone hence there cannot be any wedge failure of the slope within the level 241 - 258 m. The presence of discontinuities that plot within the toppling critical zone indicates that there is potential toppling failure on the slope at the 276 - 286 m level. In addition, the toppling failure test shows the absence of discontinuities that plot within the toppling critical zone and this indicates the absence of poten-tial toppling failure of the slope at the 308 - 312 m level. The result of the study will be useful to the man-agement of the Itakpe iron ore mine in having a proper understanding of the failure mechanism of the slopes.

Keywords

Slope Stability, Itakpe Iron Ore Mine, Intersection, Critical Zone, Failure

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	A. Chrzanowski and R. Wilkins, “Accuracy Evaluation of Geodetic Monitoring of Deformation, in Large Open Pit Mines,” 3rd IAG/12th Fig Symposium, Baden, 22-24 May 2006.
[2]	J. Sjoberg, “Large Scale Slope Stability in Open Pit Min-ing: A Review,” Lulea University of Technology, Lulea, 1996.
[3]	E. Hoek., J. Read, A. Karzulovic and Z. V. Chem, “Rock Slopes in Civil and Mining Engineering,” Proceedings of the international conference on Geotechnical and Geological En-gineering, Melbourne, 19-24 November 2000.
[4]	O. K. H. Steffen, L. F. Contreras, P. J. Tebrugge and J. Venter, “A Risk Evaluation Approach for Pit Slope Design,” 42nd US Rock Mechanics Symposium, ARMA 08-231, San Francisco, 29 June - 2 July 2008.
[5]	J. R. L. Read, “Risk and Accepted Prac-tices in Open Pit Mining Geomechanics, Keynote Address,” Aus IMM, Australia, November 2003, pp. 3-5.
[6]	A. Jarosz and D. Wanke, “Use of InSAR for Monitoring of Mining De-formations,” Proceedings of FRINGE 2003 Workshop, frascati, 1 - 5 December 2003.
[7]	P. Lilly, D. Xn and P. Walker, “Stability and Risk Assessment of Pit Walls at GHP Ore’s Mt Whaleback Mine,” An international Conference on Geotechni-cal and Geological Engineering, Melbourne, 2000.
[8]	K. Kido, R. Yoshinaka, K. Hagiwara and K. Sasaki, “Stability Analysis and Deformation Behaviour of Large Excavated Rock Slopes,” An international Conference on Geotechnical & Geo-logical Engineering, Melbourne, 2000.
[9]	E. N. Bromhead, “The Stability of Slopes,” Blackie Academic & Professional, 2nd Edition, London, 1992, pp. 1-217.
[10]	M.A. Olade, “Pre-cambian iron ore deposit and its environment at Itakpe ridge, Okene, Nigeria,” Institution of Mining and Metallurgy, Trans-action Section B, Vol. 87, 1978, pp.1-9.
[11]	A. O. Solomon, O. A. Adewole, A. U. Garba, A. A, Odunaike, S. M. Kollere and P. O. Ajiboye, ”Study on Magnetic Concentration of Nige-rian Itakpe Sinter Concentrate to a Midrex-Grade Concentrate,” Maejo International Journal of Science and Technology, Vol. 3, No 3, 2009, pp. 400-407
[12]	P. U. Umunakwe, “Developing a New Mine: The Itakpe case,” Proceedings of the Annual Con-ference of Nigeria Mining and Geosciences society, Jos., 1985.
[13]	NIOMP, “Itakpe project Report. Parts I and II,” Unpublished Report, NIOMP, Itakpe, 1979.
[14]	E. Hoek and J.W. Bray, “Rock Slope Engineering,” Institution of Mining and Metallurgy, London, 1981.
[15]	E. Hoek, “Recent Rock Slope Stability Research at the Royal School of Mines, Lon-don,” In: C.O. Brawner and V. Milligin, Eds, Geotechnical practice for stability in open pit mining, The American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., New York, 1982, p. 27.