Mobilus, I hear ya. I switched homeowners insurance to a "farm based" insurance plan because they would cover any heavy equipment rental for pennies on the dollar as an umbrella policy. IIRC a week rental of a $100K machine cost me $35. Rental fee included them repairing any hose breakage, etc. that happened to the equipment that was not due to operator error.
125-140 gallons of diesel isn't too bad, some equipment that I was quoted was rated at 8 gallons per hour when working hard, but it usually averaged 5 gph.
Then you have to figure out how to feed it daily. That's a LOT of 5 gallon cans to fill and empty.
Figure in either a fueling service, or renting a portable tank and have it filled at the beginning of the job.
D8 vs. smaller equipment means more time moving the same amount of dirt that a D8 would move, plus learning how to move dirt. Just a guesstimate here, but I'd figure on at least tripling the time of a D8. Then add in time to fuel and lube the equipment, check air filters, clean windows so you can see, etc. which is usually every 4 to 8 hrs of machine time depending on the operating conditions of the equipment. An 8 hr day "machine time" day can easily turn into a 10 hr day when everything else is factored in.
Plus, if the pond has a lot of muck in the bottom, and a person that is unfamiliar with the machine gets it stuck, that's an expensive recovery bill!
