We mobilized the off shore shaft at Lake Sakakawea while the crews started mining with the Lovat tunnel boring machine utilizing the on shore shaft. The 48 foot by 60 foot barge was assembled and equipped with a Manitowoc 3900 crawler crane with 100 foot of boom, a Cat 300KW generator set, crew shack, and misc supplies. Each corner of the barge had a 100′ steel tubing leg which would be lowered to the bottom of the lake to stabilize the barge and hold it stationary as work was accomplished. The tubes were called spuds. The barge was called a spud barge.
The 8 foot diameter steel liner of the off shore shaft extended 80 feet through water and 40 feet into the ground below the lake. Work was abandoned during the winter. Gates and Fox had the contract to complete the project. We were dewatering the shaft with electric pumps and had about thirty feet of water remaining. We would lower the pump about ten feet each time it ran out of water. Clay Paulsen, a Gates & Fox general superintendent, and John Paul White, the owners construction manager, visited the barge. Both were dressed in casual business attire from a recent meeting. They wanted to go down and inspect the shaft. We had a small round fully enclosed shaft cage for the crane, but we weren’t set up for working in the shaft. They insisted they would be fine using verbal communication to the top lander, who signaled the crane. They had one flashlight.All went well to within 20 feet of the water level. They stopped the cage and were discussing the shaft condition. Suddenly the top lander heard a gush of water enter the shaft. The water was carrying small rocks and he could hear them bouncing off the cage and steel liner. The noise overwhelmed any verbal communication. We all ran to the top of the liner and looked into the darkness. The cage was spinning and they were moving around, but we didn’t dare move the cage because we couldn’t see them. It seemed like forever before the noise and water stopped gushing into the shaft. The silence was eerie. We all heard a meek voice say “take us up”. When the cage hit the top of the shaft Clay and John Paul looked like a couple drowned rats. They were covered with dirty black coal water and mud. Clay was curious and reached out of the cage to open a two inch ball valve. The valve had over 80 psi of pressure as it blew water and debris into the shaft. The blast of debris spun the cage and he couldn’t close the valve. They lost the flashlight and couldn’t see. Clay was finally able to stop the cage from spinning and get the valve closed. They didn’t have much to say as they exited the shaft cage and headed for the tugboat ride to shore.
Clay let his curiosity over run his brain……….and paid dearly for it.