# CUCC Expo Rigging Handbook: Artificial belays - bolts

## CUCC Expo Rigging Handbook

# Bolt belays - placing and using

Most people on Austria expeditions will be familiar with the use of bolt belays from trips in the UK. In Austria, caves already explored will have bolts with the hangers removed, which can be quite hard to spot. Anyone hoping for a join-the-dots trip will be disappointed. These bolts can usually be found fairly easily by anyone familiar with expo rigging, provided a good rigging guide was drawn up by the previous explorers. Y-hangs are common at pitch heads, so check that you find both bolts. Lower down, it is as well to know whether a bolt has been placed for a rebelay or a deviation, as it may not become obvious which until some way down the pitch. Such a rigging guide is also useful to show which existing bolts should not be used. Inevitably some bolts will be badly placed, or may become damaged. It is as important not to use these as it is to find the right ones.

For new pitches when, as is often the case, good natural belays are scarce, you must place one or more bolts yourself. Doing so puts you in a position of responsibility both for the safety of future users of that bolt and for the conservation of the cave. The aim should always be to put in good bolts which will contribute to a safe rig with a minimum of further bolting needed.

This is easier said than done, and there is ample evidence of this in caves CUCC have explored over the years. The best place for a bolt may be far from obvious until the pitch has been descended. Or maybe the best place is obvious, but that place is hard to reach. It is tempting to try to reach for the best placement, but overstretching or an insecure perch may lead to a poor bolt in the perfect place. This is very much to be avoided, since it is now impossible to put a good bolt in the perfect place - the rock around the first placement will have been stressed and another bolt should not be placed closer than about 20 cm from it.

Using the Drill

Bolting by Hand

### Placing bolts

Placing a bolt is a simple matter of drilling a hole and inserting a rock anchor. The bottom end of the rock anchor is expanded by some mechanism, and thus grips tightly in the hole, resisting any attempt to pull it out. The anchor is strongest if loaded at right angles to its axis, ie. parallel with the rock surface. Hence for a vertical pitch, it is normally best to place the anchor in a vertical rock surface.

The hole may be made in either of two ways. For the penalty of carrying considerable extra weight, a cordless power drill is the quickest way to drill the hole. The heaviest item is the drill battery, which must, of course, be removed from the cave each time it needs charging. This method is of the most use where a lot of bolts need to be placed on a pitch series relatively accessible from an entrance. Lots of bolts are also needed for climbs up or exposed traverses to reach inaccessible passages.

The older (and more reliable, but slower) method is to use the anchor itself as the drill bit, driven in by use of a hammer. 8mm self-drilling rock anchors have teeth around their bottom for this purpose. The anchor is attached to a bolt driver, which is then repeatedly pounded with a hammer, whilst rotating the anchor by hand every couple of whacks. When this gets a little stiff, the anchor is pulled out of its hole and the dust and rock chips blown out. The process is repeated until the top of the anchor is just below the rock surface. A small conical "wedge" is then inserted into end of the anchor (thin end into the anchor) and the pair put back in the hole. Three or four good hard whacks with the hammer "set" the anchor by driving the wedge into the bottom end, expanding it. Beware of hitting it too many times, as this will start to weaken the rock around the anchor.

The hole produced by the power drill is a different shape from that produced by hand - since the power drill bit has a pointed end. It is also quite difficult to get the depth of the hole exactly right. For this reason, if a self-drilling anchor is set into a powerdrill hole, the wedge will not be driven into the anchor and an unsafe placement will result. To use a self-drilling anchor, it is best to under-drill the hole, and finish off to just the right depth, and a square hole-bottom with a hand driver.

More efficiently for power-drilled holes, use a form of anchor specially intended for these holes. These anchors use a smaller hole, so you get more holes for your money from one battery charge, and the design of anchor means that the bottom of the hole is not used in the setting process, and the depth of the hole is therefore less critical (as long as it is deep enough that the anchor goes right in!)

Hilti HDK spits before and after setting.

- Expedition Handbook - Contents
  - Rigging Guide
    - Introduction
    - Bolt belays – placing & using
  - Prospecting guide
  - Surveying guide
  - Rescue guide
  - Photography guide
- Index to info/topics pages
- Full Index to area 1623
  - Area/subarea descriptions
- Back to Expedition Intro page
- Back to CUCC Home page