The method for wire saw excavation provides a significant savings in time, effort, and expense in the cutting of a core of material from a solid substrate such as rock or concrete. A single downhole is formed, and a robotic excavator then forms a continuous, closed loop base passage at the distal end of the downhole to define the periphery of the core to be cut. When the base passage has been completed, the robotic excavator is removed and two subsurface guide pulleys are placed in the bottom of the downhole. A wire saw is passed from a first surface pulley around the first and second subsurface pulleys and back to a second surface pulley. The surface pulleys are advanced along the predetermined periphery of the core at the same rate as the subsurface pulleys, so that the saw simultaneously cuts the periphery and the bottom of the core.