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In a message dated 3/22/00 2:25:57 PM, fossildiver@mi*.co* writes: << ... A midnight diving expedition left one man dead in a discharge tunnel and another man trapped at the Jeffries hydroelectric plant on Lake Moultrie late Sunday night.... >> Hi Al, It was good to hear from you. I always wonder what goes on with my cave students after they leave the Yucatan. Your story sounds very much like some diving I did several years ago up in Idaho. The task was to determine the point of entry and the density of rocks (greater than 6" in diameter) that were entering the 1,500 ft. "pinstock" pipe leading to the power turbines in a hydroelectric generating station. Some of the rocks were damaging the turbine blades. The power company came to the local dive shop to ask for help and at first some advanced open water divers, needing the money, were going to go into the 6 ft. dia. pipe. The pipe dropped about 80 ft. in the first 1,000 ft. of distance and then dropped another 170 ft, in the last 500 ft. to the turbines. I convinced them that this dive was a really dumb thing for them to do in that the dive clearly required technical cave training and equipment. I went in with one other diver. The first thing we needed to do was to tell the power company to turn off the turbines and wait overnight for the water to reach some kind of equilibrium. At first they didn't want to because it meant interrupting some rural power while switching them off. But when I explained that if something went wrong and we got swept down the pipe, we'd really rather not end up as little kibbles of fish food, they agreed. Also, since I didn't want to go in carrying stage tanks, we agreed that we would only go in to a maximum depth of around 50 to 70 ft. We figured that the majority of rocks would be in the flat section rather than the steep section of the pipe. We did have an oxygen safety tank at the entrance on general principles, however. I used a line going in and was glad that I did. Part way in we stirred up some silt and it was really amazing that in this simple pipe we got confused as to which way was in and which way out. And of course inside a metal pipe, a compass was useless. Cave training pays off again. One obstacle we had not foreseen was the presence of many welding rods sticking 6" or 8" in from the circumference of the pipe where the sections had been welded together. With the silt in the pipe it was nearly impossible to see these rods if they were on the bottom. And they could do a great job snagging (and even ripping) any loose equipment. Cave training again. As a result of our dive we found that a grating near the entrance had been damaged by some large object (about a 3 ft. dia. hole in the grating) which was the source of the rocks entering the pinstock. We used the hole to enter the pipe and determined that there were virtually no rocks still in the pipe. Evidently all of the rocks that had entered the pipe had already been swept through the turbines. So our investigative effort was successful. The grating was removed with a backhoe and chains and repaired, and the turbines were turned back on. And we earned a little money as well as having an interesting diving experience. It just goes to show that with the right attitude, training and equipment all sorts of dives can be done safely. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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