Excavators digging in tandem - GIF

[nova_robotics]

And today's winner for what's-the-least-efficient-way-we-could-possibly-do-something award, we have these guys! Surely renting a stacker, or a bucket elevator, or a crane with a grab bucket, or a load up a container and lift it out with a crane, or any of a multitude of other methods that don't result in 3/4 of the material falling back into the hole you're digging would be more efficient than what these guys are doing. Must be a time and material job.