I've seen doe browsing within 150 yards of one of those 500 horsepower whole tree chippers while it was running.
Deer are curious animals. I was sitting on the edge of the power line the other day with my muzzle loader and had a doe browsing about 70 yards from me. The utility crew is rebuilding the line, a big 230 KV transmission line. They were about 300 yards away with their truck loudspeakers wide open and equipment running. She paid no attention.. Then their helicopter flew over about 50 feet above the line, close enough it blew some leaves off the trees. Well, that got on her nerves and she took off in ti the thicket. The helicopter flew down where the men were working and landed. Ten minutes later the doe and another came right back out and started browsing.
Now, if they see me they seem to run 1000 yards and never look back.