News

April 2015

In the U.S. state of Nevada, a machine from Herrenknecht has bored a tunnel for the Las Vegas water supply.  In the process, new world records were set: the high-tech boring machine (Ø7.2 meter) had to withstand water pressure of 15 bar. Las Vegas draws 90% of its water from Lake Mead, the largest reservoir in the country. But its water level is dropping, the existing water intakes are at risk. In order to tap the water deep down in the lake in future, for three years the tunnel boring machine bored its way through extremely adverse ground conditions.

On December 10, 2014, with centimeter accuracy the Herrenknecht Multi-mode TBM reached its target at the bottom of Lake Mead. Within three years it has dug a 4.4 kilometer tunnel under the largest reservoir in the U.S.A

VMT has its share at this success by providing several products on the machine that cared for an advance as accurately and efficiently as possible. Thanks to our proven TUnIS TBM^Laser the usually good breakthrough accuracy could be achieved here, too. During tunneling, our TUnIS Navigation Office and IRIS.tunnelviewer guaranteed uninterrupted provision of engineering and navigation data in real time.

The Las Vegas machine launched in late 2011 from a 180 meter deep shaft at the lakeside. For months it struggled through shattered rock and clay with full hydrostatic pressure caused by water from the lake. In doing so it had to withstand pressures of up to 15 bar, an absolute novelty in mechanized tunnelling. As a comparison: 15 bar is like diving at 150 meters or at a pressure of 15 kg per cm². With a diameter of over 7 meters and a length of 190 meters, immense forces were applied on the machine.

Work on Intake No.3 is due for completion in the summer of 2015. The new extraction tunnel will then take the lake water via Intake No.2 to a drinking water treatment plant, from where it will be supplied to households and businesses.