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.