Murphys Law implies the contractors will not be legally permitted onsite during operation so who cares what they do, but if you let the full timers play with ja

Murphys Law implies the contractors will not be legally permitted onsite during operation so who cares what they do, but if you let the full timers play with jackhammers its guaranteed some idiot will try to use the jackhammer after operation resumes. So you'd need to do something like have the safety officer personally responsible for removing the jackhammer from the premises. Or renting it, perhaps.