In open-pit mining, moving from the surface and going deeper into the pit means digging rock faces steeper and steeper. The stability of the rock faces is not just a geological issue but the most important factor in safety and cost-effectiveness in the mining process. A slope failure in the process may bring mining to a standstill, damage mining equipment, and even risk the lives of the miners. Therefore, understanding the factors affecting the stability of the slope is critical in designing a safe and cost-effective mining process.
The most significant factor affecting the stability of the rock slope is the geological fabric of the rock itself. Geological fabric is the way the rock is put together. The geological fabric includes the structures that are already in place, like bedding planes, faults, joints, and foliation. The orientation of these structures in relation to the rock face is a critical factor in the stability of the slope. The orientation of these structures in relation to the rock face is critical in the stability of the rock slope.
The strength of the rock itself and the friction in the cracks and discontinuities are critical in the stability of the rock face. However, the exposure of the rock face to air and water causes weathering, which affects the strength of the rock and the friction in the cracks and discontinuities, causing a weakening effect on the rock face itself.
Water is one of the major destabilizing factors. This is because water entering the cracks and pores increases the pore pressure, which separates the particles of the rocks and reduces the friction that keeps the slope stable. Heavy rain and rapid snow melting increase the pore pressure, which may cause a landslide. Proper drainage helps to keep the slope stable.
The way we mine the rocks is also important. Proper blasting of the rocks is very important. Improper blasting may cause the rocks behind the final wall to break off, which may cause instability. Excessive mining of the toe of the slope may cause instability. Thus, the stability of the slope depends on the proper balance of geology, water, and mining.
