Table 2. Rock properties of Itakpe iron ore mine. Table 3. Plane failure analysis input data (Itakpe iron ore mine). Figure 1. 241 - 258 m Markland test (Itakpe iron ore mine). Figure 5 indicates the dip vector plot of discontinui- ties of slope on 276 - 286 m level. The Markland test carried out shows the presence of discontinuities that plot within the critical zone which indicates the possibility of small joints were plotted on the stereonet using ROCK- PACK IIL. Figure 3 shows the dip vector plot of the dis- continuities. Markland’s test was carried out for the slope on the 263 - 275 m level. Although there are some dis- continuities in the critical zone, the intersection of the two great circles did not occur in the critical zone. The dip and dip direction of the two great circles are 025/20 and 067/25 and their point of intersection is outside the critical zone (Figure 3). Although some discontinuity values fall within the critical zone but the fact that the intersection of the great circle did not occur within the critical zone indicates that there cannot be planar failure on the slope at that level. The wedge failure -analysis in Markland carried out for the slope on 263-275m level indicates the absence of potential wedge failure because the two great circles did not intersect in the critical zone (Figure 3). The toppling failure analyses carried out for the 263-275m level indicates that the absence of any discontinuity in the toppling zone (Figure 4). — planar failure. However wedge failure analysis carried out using two great circles with orientations 076/76 and 112/43 also indicates the possibility of wedge failure, because of the intersection of the two great circles within the critical zone (Figure 5). Also the presence of discon- tinuities that plot within the toppling critical zone indi- cates that there is potential toppling failure on the slope at the 276-286m level (Figure 6). Figure 7 shows the dip vector plot of discontinuities Table 4. Result of plane failure analysis. The one hundred and twenty three dip and dip direc- tion values was plotted and the dip vector plot is indi- cated in Figure 9. Markland test was carried out using four great circles of 090/85, 073/39, 041, and 026/20 and the intersections of these great circle indicates possibility of planar failure (Figure 10). The toppling test carried out further confirmed that there is no possibility of top- pling failure (Figure 10).However the result of the anal- ysis carried out using Rockpack II indicates a factor of safety of 0.61 which is below | considered as mini- Slope stability analysis has been carried out for the East pit of the Itakpe iron ore mine. The result obtained indi- cates the presence of conditions that could lead to planar failure on the bench 263-275m. However plots within the topp evel 241 - 258 m and bench level the absence of discontinuities that ing critical zone indicates the ab- sence of potential toppling failure. Furthermore the result of the analysis carried out indicates a factor of safety of 0.61 which is below considered as minimum value for a stable slope. From t he result of this work, the manage- ment of NIOMP is requested to provide good drainage network in other to av: oid further development of gullies
