Mine waste dump stability analysis
Mine waste facilities are an essential part of any mining process. A major decision when
The most important part of the stability analysis is determining what you are trying to model (or: What problem are you trying to solve?). This requires having a detailed knowledge of the site and project background, as the foundation conditions will heavily dictate the design. One important part of stability analysis is determining what standard of design to use between Allowable Stress Design (ASD) and Load Factor Resistance Design (LFRD). The current state of geotechnical engineering is such that since LFRD is probability based, it is typically used only in soil- structure interactions (such as MSE walls and Pile design). When using ASD, it is important to choose an appropriate Factor of Safety (FS) for the project conditions. Generally, a higher factor of safety is required for situations where there is more uncertainty, but a higher factor of safety typically means an increase in cost for the mine. Need to cover high and low values – or was that specific to sheared/unsheared shales?
In order to decide how to model stability, the likely failure mode and stress conditions must be understood. Some models include (in increasing complexity): • Limit equilibrium (Rocscience Slide, Geo-Studio Slope/W) • Finite element (Rocscience Phase2) • Finite Difference (Itasca FLAC) • Distinct element (Itasca UDEC) In the case of mine waste facilities, there are usually relatively low stresses, and the structures are usually constructed from soil like materials. Therefore limit equilibrium analysis is likely going to be the model chosen as it is simple and relavent.
Another key design parameter is what building materials are available and how much? This is very important especially when it comes to construction of the facility.