OK, so this isn't Arizona again. In Arizona a sink hole is just that, a hole in the ground with rocks. I have an extensive experience with sink holes having dropped down into a number of them. But this is an entirely different experience. First, it was raining and second it has plants and is huge. You can walk down the stairs on the wooden structure to see the sink hole but cannot get off the wood to roam around. In Arizona no one cares and few people know about the sink holes. A millhopper is in a grinding mill, a hopper from which grain is supplied to the stones. I can't imagine what kind of relationship that has to this sink hole and why the Devil has anything to do with it?