Abstract: Employee #1 was operating a Caterpillar bulldozer on the 11:00 p.m. to 7:00 a.m. shift. He was working on top of the phosphate rock pile, which is approximately 30 feet high, transferring phosphate rock from the phosphate rock pile to a storage silo at the phosphate plant. This is done by working with a tunnel operator who works inside the tunnel. The tunnel operator's role is to open gates located on top of the tunnel, which is under the pile of phosphate rock. When the gates were opened, the phosphate rock slid down through the gate onto a conveyor belt and was transferred to the storage silo. The phosphate rock forms a cone on top of the rock pile as it flows through the gate. The tunnel has 70 gates and usually two are opened at a time to keep the flow of phosphate rock regulated. The tunnel operator notified Employee #1 face-to-face at the start of each shift and by radio during the shift, as to which gates are being opened. Employee #1 works around the two gates on top of the pile, pushing phosphate rock into the cones. Employee #1 did not respond to the radio when the tunnel operator notified him during the shift that the gates were being opened. The tunnel operator watched the flow of the phosphate rock and when the flow trickled off and stopped, the tunnel operator tried to contact Employee #1 by radio. When he did not get a response, he closed the gates and walked to the top of the phosphate rock pile where he found the bulldozer backed into a cone. Apparently, the bulldozer hit the far side of the cone causing the phosphate rock to break the rear window and flow into the cab. As a result, Employee #1 was covered with rocks and ultimately died from asphyxia.