I don't really believe the essence for such a massive tunnel 60 meters underground for 6 cables... Great job by some managers wasting billions.,(reply>), In the long term it will save them even more money, in a hundred years this tunnel will still he here, and you can run a ton more stuff through it too, it also allows for easy maintenance since it's not a 30cm wide tunnel that you have to dig up to modify,(reply>), Drilling a tunnel that size probably isn't terribly more expensive than drilling a smaller tunnel, and this gives room to add more cables as demand increases and maintain the existing cables.