At a tunnel launch shaft, a gantry style crane probably would be used for support of the tunneling operations, and a temporary concrete pad would be constructed around the shaft to allow for rails of the crane supports and to provide a work area. The concrete pad would be temporary and would be removed following construction. The concrete pad could be approximately 189,000 square feet and about 6 inches thick, or approximately 3,500 cubic yards. This amount of concrete would weigh approximately 7,100 tons.