How can you choose the best rock support system?

1 Rock mass characterization

The first step in choosing a rock support system is to characterize the rock mass around your excavation. This involves assessing the geological structure, rock quality, discontinuities, and stress distribution of the rock mass, using methods such as borehole logging, mapping, testing, and numerical modeling. Rock mass characterization helps you to identify the potential modes and mechanisms of rock failure, such as buckling, spalling, shearing, or bursting, and to estimate the load and deformation that your support system will need to withstand.

2 Support design criteria

The next step is to define the design criteria for your support system, taking into account your project objectives, mining method, and safety standards. When considering the criteria of support capacity, think about the maximum load that your support system can resist without failure or excessive deformation. Support stiffness is the ratio of load to deformation that your support system can sustain, which affects the energy absorption and redistribution of the rock mass. Additionally, you should consider the durability of your support system, which refers to its ability to maintain its performance over time in light of corrosion, wear, and environmental conditions. Lastly, consider how easy and fast it will be to install your support system, factoring in equipment, manpower, cost, and space requirements.

3 Support system selection

The final step is to select the most suitable support system for your excavation, based on the rock mass characterization and the support design criteria. There are many types of support systems available, each with its own advantages and disadvantages. Rock bolts, for example, are steel rods or cables that are anchored into the rock mass, providing tension and shear resistance. They are versatile, economical, and easy to install; however, they may not be effective for highly fractured or soft rock masses, or for large deformations. Another option is shotcrete, which is a thin layer of sprayed concrete that adheres to the rock surface and provides compression and shear resistance. It is flexible, adaptable, and durable; however, it may require specialized equipment, skilled operators, and curing time. Steel arches are rigid steel structures that span the excavation and provide compression and bending resistance; they are strong, stable, and resistant to corrosion but can be expensive, heavy, and difficult to install in narrow or irregular openings. Lastly, mesh is a flexible net of steel or synthetic fibers that covers the rock surface to provide confinement and reinforcement. It is lightweight, easy to install, and compatible with other support systems; however, it may not provide enough load-bearing capacity or stiffness for large excavations or high stresses.

4 Support system evaluation

After selecting and installing your support system, you should evaluate its performance and effectiveness, using methods such as monitoring, inspection, and testing. This will help you to identify any problems, failures, or deficiencies in your support system, and to adjust or improve it as needed. Support system evaluation is an ongoing process that should be conducted regularly throughout the mining operation, as the rock mass conditions and the stress environment may change over time.

5 Support system optimization

When selecting a rock support system, the ultimate goal is to optimize the balance between safety, stability, and productivity. To do so, you should consider support optimization, integration, and innovation. Support optimization is the process of finding the optimal combination of support types, quantities, locations, and timings based on rock mass characterization, design criteria, and mining method. Support integration involves integrating the support system with other aspects of your mining operation such as ventilation, drainage, blasting and ore extraction. Lastly, support innovation is exploring new or improved support systems, methods or technologies based on the latest research and best practices in rock mechanics and ground control.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?