Hale Lake is a really interesting karst feature that is somewhat anamolous, or stand-alone. It's either a dormant sinkhole or a large subsidence feature. Actually, there's not really any such a thing as a dormant sinkhole. At the moment, this one holds water, which may be due to montmorillinite clay - a tactic by ranchers and others to seal cattle tanks, so water will stay on the surface. Eventually though, there could be a catastrophic collapse or other geologic action that would make the sink more active.
Hale Lake Sinkhole Karst Feature, as sinkholes go, could indicate a void somewhere below, where stoping has occured up to the surface to form the sink. With any luck, it's the Fort Stanton-Snowy River Cave System - there are passages at the far southwest end of Snowy River Passage that split off and are headed south for Eagle Dry Lake subsidence features on Eagle Creek, which are as large or larger than Hale Lake. If they keep going south, Hale Lake is kind of in line. Already, at 12 miles long, Snowy River Passage is the longest cave passage in the world; the cave overall is 31.345 miles, almost the same length as Carlsbad Caverns. At the current end-of-survey station, the Snowy Passage is large enough to hold a house - it is a big cave system. Hale Lake Sinkhole is about 15 miles south-southeast of current end of survey. So far, there's only one known entrance - back by the fort and it takes all day just to get to base camp at Midnight Junction out near those break-away passages. If those passages are below, it will make Fort Cave Cave one of the longest caves worldwide. A drawback - just to get to Midnight Junction - that's among the most remote places on Earth that humans have ventured...............any cavers out there might as well be on Mars...................!
One thing really critical about your pending visit - if it's been raining, and FR 443 is wet, stay way away - do not go on a wet FR 443, and certainly not into the subsidence basin, because the clay there will cause your wheels to hopelessly spin. And the only way you're getting out is waiting until it dries - or - off roaders come along - they'll help you alright, as that's their baliwick and they're good at that. But more likely than not, you're walking out, unless you have camping time on your hands.