The fast-growing stalactites form via processes very different from calcium carbonate stalactites found in limestone caves. Limestone is not soluble in water. When carbon dioxide (from decaying plants in the soil above the cave) mixes with water, it forms a very weak carbonic acid. This turns the calcium carbonate into calcium bicarbonate, which dissolves. When drips are exposed to air in the cave, a little carbon dioxide escapes from them into the atmosphere, which reverses the process and precipitates a small amount of calcium carbonate. The upper average rate for limestone stalactite growth is ten centimeters per thousand years, with lower growth rates outside of tropical areas.
Fast-growing stalactites, on the other hand, either grow from gypsum through an evaporative process, or they form from concrete or mortar. When water is added to concrete, one product is calcium hydroxide, which is about 100 times more soluble than calcite. The calcium hydroxide absorbs carbon dioxide from the atmosphere to reconstitute calcium carbonate.
The tunnel was constructed from indigenous limestone blocks.
Have a look:
http://outdoors.webshots.com/photo/2915088580098995611JmCRBb
Dr. Paul Guptill, was, by odd coincidence, the state’s reknowned “resident” scientist who visited schools specifically for the purpose of educating kids about science.
He was our “teacher”, in name, for that particular day.
My “less than scientific observation” was eye witness testimony to what I and everyone else saw that day.
*shrug*
Pick that apart how ever you may.
I saw them.
End of story.