# Investigation of Steep Waste Dump Slope Stability of Iron Ore Mine--A Case Study
## 4 Conclusions  
This research work presents a novel approach to analyzing the failure and deformation field of slopes, which has been validated in particular cases for Waste Dump#1, a specific highly steep slope at Ziluoyi Iron Mine. The present study draws conclusions from a combination of field data, laboratory direct shear tests, GEO-SLOPE stability calculations, and numerical simulations of PFC granular flow to evaluate the movement of the granular materials. The main obtained results can be summarized as follows:  
1. The open-pit mine of Ziluoyi has a slope with a height of 78 m and an angle of 25\({}^{\circ}\), with a base slope angle of 22\({}^{\circ}\), and has a significant step. According to the GB50421-2018 \"Standard for Waste Dump Design of Nonferrous Metal Mines\", this type of slope is classified as a Grade 3 waste dump. For such slopes, the safety factor ranges from 1.15 to 1.20, as per GB50421-2018;
2. The direct shear tests on soil samples taken from the dump site revealed the following key mechanical parameters: an average cohesion of 4.80 kPa and an average internal friction angle of 25.63\({}^{\circ}\). However, the GEO-SLOPE calculations based on the Morgenstern-Price approach indicated that the actual slope stability factor of 1.047 does not meet the required stability criteria. To resolve this critical concern, appropriate rectification procedures including the construction of safety platforms, relocation, and removal of unstable soil were implemented. These modifications to the understudy slope improved the overall slope stability factor to 1.219 and were in line with safety standards;
3. The efficiency of the PFC-based model in rational capturing the mechanical strength behavior of soil in the presence of various vertical stresses was demonstrated by comparing it with the experimental results. The obtained results are indicative of the fact  
Figure 15: Particle displacement distribution in the modified section: (**a**) top view of the two-dimensional displacement, (**b**) side view of the slope displacement in the \(x\) direction, and (**c**) side view of the slope displacement in the \(y\) direction. that such a mode is capable of fairly precise capturing of the experimentally observed shear stress-shear displacement with a relative error lower than 6% in most cases. * Subsequently, the PFC simulations were utilized to model the slope morphology and particle displacement before and after rectification. The obtained results reveal that through the application of the post-rectification, the area of sliding and the proportion of sliding particles were substantially reduced by 25%, with a 41.8% reduction in sliding volume. These results demonstrate the effectiveness of the slope remediation measures. The results of this study highlight the importance of combining GEO-SLOPE numerical calculations with numerical simulation of PFC particle flow to accurately assess slope stability and the amount of slope failure. This approach offers a more precise way to prevent and manage slope stability in open-pit mines, which is essential for ensuring safe and efficient mining operations. The stability of slopes is a critical concern for geotechnical engineers due to the potential for disasters associated with slope failure. With a wide range of geomechanical factors at play, it is essential to use effective machine-learning-based algorithms and intelligence algorithms [52; 53; 54; 55; 56; 57; 58; 59; 60] for rational predicting of the safety factor of a diverse range of slopes (with and without rectification) under various conditions (normal, rainfall, and seismic loadings). These algorithms will provide a suitable bed to appropriately optimize the slope design, leading to more economic and safe slope structures. The application of these efficient algorithms to the engineering problem studied here can be considered as a hot topic for future research works. Conceptualization, X.D. and Z.A. ; methodology, W.Q., Z.Y., I.M.J. and Z.Z. ; validation, X.D., Z.A., X.L. and Y.T. ; formal analysis, Z.A.