Which of the following statements is true about dual delay detonators?

• A. They initiate with a light signal
• B. They have a less complex design
• C. They allow for both in-hole and surface initiation
• D. They are typically used in mining only

Answer: (C)

The correct answer indicates that dual delay detonators allow for both in-hole and surface initiation, which is a significant feature of this type of detonator. Dual delay detonators are designed to enhance the safety and effectiveness of blasting operations in mining. Their ability to be initiated from different locations provides flexibility in how a blast can be executed, which can help mitigate risks and improve timing for optimal fragmentation of rock.

This feature is particularly important in mining operations where precision is critical to achieving desired results while minimizing the impact on nearby structures and ensuring the safety of workers. By allowing for initiation from both in-hole and surface positions, these detonators can accommodate various blasting scenarios and provide miners with the ability to control the detonation sequence more effectively.

In contrast, the other options either misrepresent the functions or applications of dual delay detonators or inaccurately simplify their characteristics. For instance, while they can have less complex designs compared to other types, the specific capabilities associated with initiation make the feature of enabling both in-hole and surface initiation paramount. Additionally, dual delay detonators are not limited to mining alone; they have applications in various other industries as well, thus ruling out the idea that they are typically used in mining only.