Natural anchors
There are many natural features at cave entrances or underground that may be in a location and have the strength to be used as a rigging anchor. Natural anchors are preferred by traditionalists who don’t like the idea of leaving human artifacts like bolts and hangers in a cave.
Caving Vlog #71 This is Part 2 of a series of videos on rigging in caves. This covers the use of natural anchors in rigging. Natural anchors includes trees near entrances, as well as rocks, natural bridges, pillars, chockstones, flakes, threads, bollards and secondary deposits.