Final answer:
The length of tubing for a Nonel assembly in blasting operations depends on the hole's depth, safety, and manufacturer's instructions. It must extend from the detonator to the surface and allow safe initiation.
Step-by-step explanation:
The length of tubing for a Nonel assembly when loading a hole will depend on specific circumstances of the blasting operation, including the depth of the hole, the layout of the blast site, and safety considerations. Nonel, short for non-electric, utilizes a shock tube with a small amount of reactive material that transmits a signal when initiated. The length of the Nonel lead line should be long enough to extend from the detonator at the bottom of the hole to the surface and additionally provide sufficient length for hook-up to the blasting machine or to extend to another hole. The exact length should be determined by assessing the depth of the hole and incorporating any additional length that would ensure safe handling and initiation of the blast. Furthermore, following the manufacturer's guidance and safety regulations in your jurisdiction is critical.