If you want to dig a BIG hole quickly, go buy a TBM: Tunnel Boring Machine. This behemoth carves through hard rock more efficiently than conventional drilling and blasting methods. As its massive cutter head rotates, excavated material, known as muck, is channeled to a train of conveyors behind the rig which removes it from the site.

The Robbins Company produces TBMs for large scale projects like mining, transporation and utilities.

Watching a TBM punch its way through a mountainside must be an awesome experience. It’s not hard to imagine why conspiracy theorists have been weaving this monster mole into their DUMB theories.

I’m not passing judgment here, DUMB stands for Deep Underground Military Bases. Different versions of this theory exist but most share the belief that hundreds of secret underground facilities exist across the country, connected by futuristic high-speed rail systems.

The TBM, of course, is accused of being the tool of choice for drilling this supposed railway network. Can this be true? Let’s do the math. Based on the best data I could find, the TBM is capable of digging 100 feet per day. The overall length of these railways is roughly 5000 miles. So it would take 723 years to complete this project. Unless the Indians started digging these tunnels 400 years before the Europeans found North America, this myth is busted.

To prove such an accomplishment is possible, the DUMB proponents cite as evidence a 1972 scam Rand Corporation pitched to the US Government. In The Very High Speed Transit System, Rand claims it could bore a tunnel from New York to L.A. using a nuclear powered TCM capable of melting rock. Once completed with the digging, they would whip up a bullet train that shot from coast to coast at 14,000 mph using a magnetic levitation system.

Let’s say, since 1972, Rand Corp has secretly been melting 5000 miles of tunnels under our feet. Why would our government pay for this multi-billion dollar effort, then keep it secret? So they can shuttle Generals between bases via endless miles of dark and drippy tunnels? Uh, no thanks, I’ll take the private jet.

Rand executives, you may want to blow the dust off your plans and talk to the Mexican drug traffickers. They have deep pockets and need a boost to their current tunneling operations.

Back to reality. Here are some cool images of the real TBM in action: