This particular cave is active, which means that water is still flowing through it. Shortly after the water flows out of this cave it joins a small stream, much of the streams water is derived from the cave. Just a few hours west of Red River Gorge is Mammoth Cave National Park, one of the largest caves in the world. But in the area of the gorge all of the caves are relativly small. The reason for this difference is the thickness of the limestone layers in each location.
Caves are only stable within the limestone layer that they exist.
If another type of rock is reached then the cave becomes unstable and collapses. So as you can probably guess the limestone layer around Mammoth is very thick, while in the gorge it is much thiner.