They call that machine a channel digger or road scraper here in Australia. That kind of machine can fill a semi up in 3-5 minutes depending on capacity, can fill a dump truck up in 2-3 minutes. These machines do work, they don't mess around when it comes to gouging out a trench, be it for kerbing and channeling or for road widening or whatever project it is needed for, they move dirt and lots of it!