How is the risk of fly rock mitigated in blast patterns?

• A. By using expansive blasters
• B. Through the use of cross ties
• C. With increased detonation energy
• D. By monitoring atmospheric conditions

Answer: (B)

Mitigating the risk of fly rock in blast patterns is primarily achieved through the use of cross ties. Cross ties are explosive charges placed between primary charge locations in a blast pattern. Their purpose is to help control the energy distribution and fragmentation of the rock, ensuring that the force of the blast is directed downward and towards the center of the blast area. This reduces the likelihood of rocks being propelled outward, thus minimizing the risk of fly rock, which can pose a significant safety hazard to personnel and equipment in the vicinity.

While other methods may play a role in blast design and execution, they do not specifically target the primary mechanism of controlling rock displacement in the same way cross ties do. For example, using expansive blasters or increasing detonation energy could potentially enhance fragmentation but may also inadvertently lead to increased risks of fly rock if not managed properly. Monitoring atmospheric conditions is essential for safety but does not directly alter the physical parameters of the blast that govern fly rock risk. Therefore, the most effective way to mitigate this risk specifically within the context of blast patterns is through the strategic use of cross ties.