Does anyone know about how long it would take a healthy man and woman to dig a semi-shallow grave, lets say 2'x2.5'x6' (30 cubic ft.) near the eastern edge of the Mojave Desert? Heat would be a factor, I'm sure, but assume they're well hydrated with endurance. I'm more curious about the earth they're moving. What's the dirt like out in those super-remote areas between mountains? How would it feel under a good, sharp, mid-sized shovel? Anything you could tell me about the density, consistency, grit, etc. would be a big help. Thanks!