Dump truck costs

I don't have any figures but I can tell you dump trucks are quite a bit more maintenance intensive than a OTR truck. Those jobsites can be brutal on a truck. Expect at least one flat a week, and excellerated tire wear.

 

Air bag a month, high idle/pto times, front end always out of alignment, kingpins, and a lot of competition.

 

You absolutely must be vigilant on maintenance, especially greasing.
I'm in for a safety right now on my four year old super-b hopper bottoms, we do a lot of gravel roads. I grease every few weeks. My S-cams are still good.
Meanwhile a two year old set of trailers is in here getting a complete brake job. Driver didn't grease it but twice a year, the S-cams wore out and levered over the brake shoes taking them out and scoring the brake drums.