What defines the minimum safe distance for re-entry after blasting detonation?

• A. Re-entry is allowed after 2 minutes
• B. Re-entry depends on weather
• C. Re-entry must be approved by a supervisor only if a blast mats are used
• D. Re-entry distances are defined by the blasting plan and blasting mats; workers must stay clear of blast area until cleared by the supervisor

Answer: (D)

Re-entry after blasting is governed by the blasting plan, which specifies the safe distance and conditions under which workers may enter the blasted area. The plan may call for using blast mats to contain debris and reduce flyrock, and these mats influence how close workers can re-enter, but they do not establish safety by themselves. Before anyone returns, a supervisor must clear the area, confirming that all workers are outside the defined blast zone and that the blast is complete and free of hazards such as misfires. Time since detonation or weather alone do not determine the minimum safe distance; weather can affect visibility and dust, but it doesn’t set entry safety. So the minimum safe re-entry is defined by the blasting plan in conjunction with the use of blast mats, with workers staying out of the blast area until cleared by the supervisor.