Global Rigging & Transport, LLC (GRT) was retained to relocate four concrete tunnel sections within the Round Mountain gold mine facility in Nevada. Each tunnel section, weighing up to 1,100 tons, was lifted using a special purpose transporter, moved along approximately 1.5 kilometers of the terrain with slopes of up to 5%, and set at the new location.
GRT conceptualized the transporter scheme and retained Liftech to design the transporter assembly and verify the tunnel structure for the transport loads. The transporter was supported on 28 hydraulically connected dollies to provide a three-point support. Each tunnel section was lifted using rods that were supported on jacks mounted on top of beams spanning over tubular columns.
For traveling on an inclined grade, each tunnel section was held in position with longitudinal rods attached between the tunnel bottom and the transporter bottom. Long cylinders with jacks between the tunnel and the transporter in the transverse direction kept the transporter frame from spreading and overloading the dolly wheels. The tension in the longitudinal rods and the transverse jacks was continually adjusted as the tunnel section was raised or lowered.
The tunnel lift rods were attached to brackets mounted on each side of the tunnel walls at four locations with bolts drilled through the 27-inch-thick walls.
Los Angeles, California, USA