Steel,
Before I got my tractor, two summers ago I hired this guy about a mile away to mow for me. He charged my $60.00 an hour. He had a 5 ft bush hog with a JD tractor I believe it was around a 40 horsepower. He didn't deduct for hitting my drain field lines either. And yes I did show him where they were before he started. He clipped all of them off on one side. I had to dig up 5 of them and re-set them.
Murph