Ute Water Conservancy District has awarded a $14.1 million contract for a 4 km-long, 3.18 m-diameter tunnel in sandstone and siltstone to a jv of Affholder and Barnard Construction. Affholder will use a Robbins hardrock TBM on a 20-month programme commencing April, 2000. January 2000.
Contractor reports two sections of tunnel required, lengths 3.1 km and 1 km. Geology is sandstone up to 25,000 psi, shales and siltstones to be supported by rockbolts, wire mesh, and shotcrete. TBM upgraded by Robbins with new main bearing and cutterhead. Tunnel designed by Lachel & Associates of Denver, CO for GEI Consultants of Englewood, CO. More information from www.robbinstbm.com May 2000.
Robbins reports major upgrade of Affholder TBM to cope with harder 25,000 psi ground. Modifications include new water-cooled motors to increase power from 500 hp to 800 hp, larger diameter gripper rams, and new main bearing and cutterhead. Tunnel designer is Lachel & Associates led by GEI Consultants of Englewood, CA. Visit www.lachel.com and www.robbinstbm.com June 2000.
Second Plateau Creek tunnel 3.05 km-long in sandstone will be holed through by Affholder using modified 3 m-diameter Robbins Model 91-155 TBM on March 16th, 2001. See Recordbreakers (Hall of Fame) for details of first drive. Visit www.robbinstbm.com 11/01.