No-one has mentioned the general public's view in this:
Who has the God given right to decide whether aerial ops will / will not directly affect the safety of members of the public?
If you, as a prospective passenger read a sign at the entrance to the cable car saying:
The public is advised that during their journey, there is a risk of death or injury from falling debris.
would you and your family climb into that car?
Health and safety was introduced to protect the 'innocent'. In this particular instance, there can be NO excuse for NOT closing the cable car.
IF the project is that important, then the planners should build in a closing period for the cable car company and compensate them for their reduced earnings. If the local community wants this they should pay for it.