Engineering, 2011, 3, 602-608 doi:10.4236/eng.2011.36072 Published Online June 2011 (http://www.SciRP.org/journal/eng) Copyright © 2011 SciRes. ENG Slope Stability Analysis of Itakpe Iron Ore Mine, Itakpe, Nigeria Rasheed A. Adebimpe 1* , Jide Muili Akande 2 , Chinwuba Arum 3 1 Department of Mineral Resources Engineering, The Federal Polytechnic, Ado-Ekiti, Nigeria 2 Department of Mining Engineering, Federal University of Technology Akure, Akure, Nigeria 3 Department of Civil Engineering, Federal University of Technology Akure, Akure, Nigeria E-mail: rasheed4u1@yahoo.com Received February 24, 2011; revised April 1, 2011; accepted April 10, 2011 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 1. Introduction The Itakpe iron ore deposit lies 4 kilometre south – west of Ajabanoko iron ore deposit and is located within lati- tude 8˚ and 9˚ and longitude 7˚ and 8˚. The Itakpe iron ore deposit is operated as an open pit mine and has mul- tiple benches. The bench geometry was chosen based on the stability assessment of the slope. The stability of a slope should be viewed from both the safety aspect and economic aspect. The stability of bench walls in an open pit mine is a major safety issue, and there is usually a slow movement of the rock formation before a failure actually occurs [1]. In the process of mining the ore an opening is created which necessitates the creation of slope. The actual slope angle used in the mine depends upon 1) the presence of haulage roads, or ramps, necessary for the transportation of the blasted ore from the pit, 2) possible blast damage, 3) ore grades, and 4) economical constraints [2]. Rock slope failures are geological events controlled by natural processes [3]. Slope failures are typically considered at three levels: 1) Global in which the entire pit wall might collapse the mine 2) inter-ramp in which a partial wall failure might substantially affect the recovery of ore 3) bench in which slope failure only affects the local opera- tions in the vicinity of the failed bench [4]. The optimum slope design of a pit requires the deter- mination of the most economic pit limit which normally results in steep slope angle as in this way the excavation of waste is minimised [4]. In any economic open pit mine, a variety of slope instabilities may be present at various locations in the mine at anytime, the successful management of these features is the art of good open pit mining [3]. In general as the slope becomes steeper, the stripping ratio (waste to ore ratio) is reduced and the mining economics improves [4]. Therefore the primary objective of a mine slope designer is to reduce the quan- tity of waste to be excavated and maximise the quantity of ore produced. This is very important especially at the planning stage of the mine. The difficulty in determining the acceptable slope angle stems from the existence of uncertainties associated with the stability of the slopes