| Slope scale | Consequences of failure | ||
| Low | Medium | High | |
| Bench |
| FoS ≥ 1.1 PoF ≤ 25% - 50% |
|
| Inter-ramp | FoS ≥ 1.15 - 1.2 PoF ≤ 25% | FoS ≥ 1.2 PoF ≤ 20% | FoS ≥ 1.2 - 1.3 PoF ≤ 10% |
| Overall | FoS ≥ 1.2 - 1.3 PoF ≤ 15% - 20% | FoS ≥ 1.3 PoF ≤ 5% - 10% | FoS ≥ 1.3 - 1.5 PoF ≤ 5% |