The Pin-and-Resin Method for Repairing Broken Stalagmites
Smaller stal, broken in two, are quite easily repaired in the cave. Stalagmites which are broken into numerous pieces may be better repaired out of the cave. The decision will depend on the distance into the cave, number of pieces and the weight, number of people to move the formation, time available, etc.
It may not be necessary to pin: the more oblique the break the more necessary a pin becomes. A pinned joint is always likely to be stronger than a simple surface contact. The two methods, underground and out of the cave, are detailed below.

Repairing Broken Stalagmite in the Cave
This technique can be used for repairing stal which is in two pieces. Photographs are by Ian Chandler (IC) or Juan Corrin (JC).

JC	Equipment portable drill, alcohol, cloth, permanent marker felt tip pen, knife, drill bit 6mm, drill bit 8mm, 6mm diameter threaded pins about 8cm long, 5mm diameter (or less) blow tube, araldite rapid 2 parts, mixing spatulas, mixing trays or plates, spatula for shaping dust / araldite.
IC	Technique 1: Cut off a tiny piece of permanent marker tip and place in the centre of the bottom piece of stalagmite. 2: Match the upper piece of stal precisely over the lower piece and push together. Ink marks on each piece will now show the places to drill. 3: Drill a 40mm deep hole in the bottom surface of the upper piece using the 6mm drill bit, without hammer action. An assistant should hold the stal so that the hole is drilled in at right angles. Blow out the calcite dust using the blow tube.
IC	4: Clean the lower surface of the upper piece with alcohol on a cloth. 5: Mix a small amount of araldite rapid on a mixing tray. Coat half the length of the threaded bar with the resin and push into the drilled hole. Place to one side.
IC	6: Drill an 8mm diameter hole in the bottom piece, on the felt tip mark, and at right angles without hammer action engaged. Blow out the calcite dust. 7: Place the upper piece over the lower piece. The two pieces should fit together. If not, the bottom hole should be widened. 8: Clean the upper surface of the lower piece with alcohol on a cloth. 9: Mix the required amount of araldite rapid on a mixing tray. 10: Drop some of the resin into the lower hole and spread resin over the lower surface, but not to the edge. 11: Mate the upper piece with the lower and press together until the crack between the pieces is at a minimum. 12: If required, fill in any holes around the join with araldite rapid or the resin mixed with some of the calcite dust (plus some sediment for colour matching).
IC	13: Mark the repaired stal with tape as a temporary measure and decide on future conservation measures.

Problems
At cave temperature (10C), the araldite rapid is stiffer than at room temperature. This makes it difficult to dribble the resin into the 8mm hole. It also takes longer to cure and harden.

JC	Equipment Drill, alcohol, cloth, permanent marker felt tip pen, knife, drill bit 6mm, drill bit 8mm, 6mm diameter threaded pins about 8cm long, 5mm diameter (or less) blow tube, araldite rapid 2 parts, mixing spatulas, mixing trays or plates, spatula for shaping dust / araldite, work bench, large diameter plastic pipe and / or coke bottle or similar, bubble wrap, sand paper and or Dremel tool.
JC
JC	Technique Decide on the order in which the pieces are to be stuck together. Most will be drilled top and bottom. A better glued joint will occur if the stal is kept in the natural upright position. It is probably best to use a pin for each joint, even if the joint is horizontal. Drilling can be carried out on a work bench with the stal horizontal. A pillar drill with the stal vertical may be a better proposition. For each joint 1: Cut off a tiny piece of permanent marker tip and place in the centre of the bottom piece of stalagmite. 2: Match the upper piece of stal precisely over the lower piece and push together. Ink marks on each piece will now show the places to drill. 3: Drill a 40mm deep hole in the bottom surface of the upper piece using the 6mm drill bit, without hammer action. The work bench should hold the stal so that the hole is drilled in at right angles. Blow out the calcite dust using the blow tube. 4: Clean the bottom surface of the upper piece with alcohol on a cloth. 5: Mix a small amount of araldite rapid on a mixing tray. Coat half the length of the threaded bar with the resin and push into the drilled hole. Place to one side.
JC	6: Drill an 8mm diameter hole in the bottom piece, on the felt tip mark, and at right angles without hammer action engaged. Blow out the calcite dust. 7: Place the upper piece over the lower piece. The two pieces should fit together. If not, the bottom hole should be widened. 8: Clean the surface of the lower piece with alcohol on a cloth. 9: Mix the required amount of araldite rapid on a mixing tray. 10: Drop some of the resin into the lower hole and spread resin over the lower surface, but not to the edge. 11: Mate the upper piece with the lower and press together until the crack between the pieces is at a minimum.
JC	12: If required, fill in any holes around the join with araldite rapid or the resin mixed with some of the calcite dust (plus some sediment for colour matching). 13: Each section should be left for 3 or 4 days before any further drilling for another joint is attempted.
	14: Any araldite that is visible will be shiny. This can be cut back and roughened with a Dremel tool and grinding bit (or possibly emery paper). The final clean is with a soft cloth and water.
	15: If the calcite shatters around the drilled hole, the threaded bar can be fixed in place and the pieces glued around it.
	16: The completed pieces of repaired stal can be transported into the cave in plastic sewer pipes packed with pieces of polystyrene sheet. A karabiner is attached near the top of the pipe to clip into tackle sack closing cord. 17: The installation of the repaired stal can be viewed here.
JC	Considerations The taller the repaired stal becomes, the more likely it is to topple over. Various containers can be used to widen the base area and provide stability, e.g. a large Coke bottle or a 110mm diameter plastic sewage pipe have both proved useful. The tube was filled with sand to lower the centre of gravity and to keep the stal at a good working height for the top joint. Both sides of one joint shattered when being drilled. In this case the pin was glued into the upper section and the pieces glued around the pin. Luckily the shattered pieces of the base section glued together in a stable manner. The base of the repaired top section is mated with the top of the bottom section using a felt tip fragment, the holes drilled into both faces and the threaded pin glued into the upper section. The final glued connection was made on site. The base of the bottom section, which will mate with the stump in the cave, also needs to be aligned and marked. With forward thinking, the stump and its mate can be marked before the latter is brought out of the cave. However, in this case, the lower pieces had been glued together before the final fixing was thought about. The 6mm hole should then be drilled into the base of the lower section outside the cave and the hole packed with a sliver of foam rubber to be marked in the cave with the felt tip ink. JSC 30/11/08, 18/1/09