>>12405990The paper I'm citing says they got the data for Fig 5 from "HM Treasury. 2010. Infrastructure cost review," but it doesn't seem to point to specific projects.
>>12406000Musk only ever said "approximately 10 million dollars," so I'm assuming he's within the same ballpark as bong/euro tunneling in lack of more specific foigures. Admittedly I can't find specific data for the tunnels so i can't compare every single confounding variable regarding the geology or anything else that might set the location apart from Hawthorne. However, even in a best case scenario this means that Musk isn't underbidding his competitors by nearly an order of magnitude for an equivalent volume of tunnel.