As others said, you can reuse cars (if a car does 100 1km journeys per charge interval the materials cost for cars and gravel become comparable) and a custom bu

As others said, you can reuse cars (if a car does 100 1km journeys per charge interval the materials cost for cars and gravel become comparable) and a custom built car can be cheaper, too. The volume may be another challenge though: 1.33*10^11 kg is roughly 0.1 km^3 of gravel/dirt. So we need to move a cube of dirt ~450m in size up and down 1km each day. Not impossible, but presents bit challenges on its own imo.