A combination of heat and high pressure allow this semi-autonomous boring robot to tunnel through undrillable rock - credit: Petra San Francisco startup Petra says its new contactless thermal drilling robot can make steady progress through the hardest rock on Earth – stuff that would normally destroy drilling equipment – so quickly and cheaply that it could make a lot of underground infrastructure projects economically feasible. The semi-autonomous "Swifty" robotic system can create 18-60 inch (46-152 cm) diameter tunnels through any geology, blasting the rock with an extremely hot, high-pressure spallation head such that it glows, chars and flings away....
