What is the recommended extra length of detonating cord for surface connections in a blast hole?

• A. 1 foot
• B. 2 feet
• C. 3 feet
• D. 5 feet

Answer: (C)

The recommended extra length of detonating cord for surface connections in a blast hole is typically three feet. This length allows for sufficient length to ensure a secure connection and helps to accommodate movement or positioning during the connection process. A length of three feet is practical as it provides flexibility in making adjustments to ensure the connection is effective and reliable, which is crucial for safe and successful detonation.

In mining operations, the proper handling and connection of detonating cord are essential to ensure that the explosives function as intended without any mishaps. Having a little extra length reduces the risk of accidentally cutting or compromising the cord during setup and ensures that the connection to the detonator can be easily secured and managed.