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Jobs Done Well. Kiewit Underground is a leader in the tunneling industry. Headquartered in Omaha, Neb., we construct underground facilities across the U.S. and Canada. We have proven tunneling experience with a variety of tunneling and excavation methods. Our drill and blast projects include: Drill and Blast Lake Hodges Tunnel The Lake Hodges Tunnel consisted of a 5,850-foot-long, 12.5-foot horseshoe tunnel excavated, using controlled detonation drill-and-blast methods. The tunnel was excavated along a continuous slope starting at 2 percent and proceeding to 19 percent. Ground conditions were predominantly a granitic material requiring pattern bolting for ground support. Instances of shear and fault zones required additional mine straps. Primary tunneling equipment included a drill jumbo and tunnel muckers. A detailed seismographic program was initiated to continually monitor any effects of blasting to existing residences and facilities. Harlem River Tunnel The project consists of two 165-foot-deep circular shafts connected by a 675-foot-long horseshoe tunnel directly beneath the Harlem River. Bedrock in this part of Manhattan is white marble and found at a depth of about 70 feet below grade. Overburden at the shafts is a mix of sandy and silty soils with support of excavation in the overburden being secant pile walls. Once in rock, conventional drill-and-blast techniques were used. Initial rock support consists of 9-foot-long swellex friction bolts and shotcrete in most areas, with 15-foot-long swellex bolts being used in the soil/rock interface and turn under areas. Primary tunneling equipment included a drill jumbo and tunnel muckers. Richland Creek The Richland Creek tunnel consisted of a 5,700-foot-long tunnel 8 feet in diameter between two shafts. Controlled detonation drill-and-blast tunneling method was used for 4,300 feet of hard rock consisting predominately of 33- ksi gneiss. Both jacklegs and a drill jumbo were used for blast hole drilling in the small diameter tunnel heading. Tunnel spoils were hauled with small locomotives and muck cars. Ground support for the tunnels was provided a combination of steel sets and rockbolts.

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  • Jobs Done Well.

    Kiewit Underground is a leader in the tunneling industry. Headquartered in

    Omaha, Neb., we construct underground facilities across the U.S. and Canada.

    We have proven tunneling experience with a variety of tunneling and excavation

    methods. Our drill and blast projects include:

    Drill and Blast

    Lake Hodges Tunnel

    The Lake Hodges Tunnel consisted of a 5,850-foot-long, 12.5-foot horseshoe

    tunnel excavated, using controlled detonation drill-and-blast methods. The tunnel

    was excavated along a continuous slope starting at 2 percent and proceeding to

    19 percent. Ground conditions were predominantly a granitic material requiring

    pattern bolting for ground support. Instances of shear and fault zones required

    additional mine straps. Primary tunneling equipment included a drill jumbo and

    tunnel muckers. A detailed seismographic program was initiated to continually

    monitor any effects of blasting to existing residences and facilities.

    Harlem River Tunnel

    The project consists of two 165-foot-deep circular shafts connected by a

    675-foot-long horseshoe tunnel directly beneath the Harlem River. Bedrock in this

    part of Manhattan is white marble and found at a depth of about 70 feet below

    grade. Overburden at the shafts is a mix of sandy and silty soils with support of

    excavation in the overburden being secant pile walls. Once in rock, conventional

    drill-and-blast techniques were used. Initial rock support consists of 9-foot-long

    swellex friction bolts and shotcrete in most areas, with 15-foot-long swellex bolts

    being used in the soil/rock interface and turn under areas. Primary tunneling

    equipment included a drill jumbo and tunnel muckers.

    Richland Creek

    The Richland Creek tunnel consisted of a 5,700-foot-long tunnel 8 feet in diameter between two shafts. Controlled detonation drill-and-blast tunneling method was used for 4,300 feet of hard rock consisting predominately of 33-ksi gneiss. Both jacklegs and a drill jumbo were used for blast hole drilling in the small diameter tunnel heading. Tunnel spoils were hauled with small locomotives and muck cars. Ground support for the tunnels was provided a combination of steel sets and rockbolts.

    http://www.kiewit.com/projects/power/harlem-river-tunnel.aspx?sc_lang=enhttp://www.kiewit.com

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