If Arcbyt is the tunneling company Pyrogenesis is working with look at the information in this patent. Paragraph 0034- "In one embodiment, the base RBR, which bore a tunnel with a 1-meter diameter, has a minimum requirement of 40 megawatts (MW), 72 torches at 0.5 MW=36 MW plus 4 MW (about 10% of the aggregate capacity of the plasma torches) for propulsion and other auxiliary systems.  Paragraph 0040- talks about tunnel sizes- 0.5 meters to 2 meters in diameter and larger versions 10 meters or larger.  0043- RBR is designed to accommodate at least 110 carts, so it can tunnel at least 1 kilometer from any staging point. https://www.freepatentsonline.com/20200217199.pdf  Interesting reading.