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It's Where We Began And Where We Continue to Lead

Starting in the 1960s, the AFFHOLDER tunneling team helped build the modern tunneling industry from the ground up. Led by industry veterans Bob Affholder and Jerry Shaw, AFFHOLDER ranks among the most experienced and best-equipped tunneling contractors in the United States. And we’re proud to serve customers in the municipal, energy, and industrial sectors, providing a range of solutions for water, sanitary and stormwater pipeline.

When your situation calls for complex pipeline expansion or simple repair, trust AFFHOLDER to expertly excavate tunnels from 4-foot diameter to 32-foot arch-shaped SEM tunnels in all kinds of ground conditions, including soft-ground, soft-rock, hard-rock, and hand-mined.


Deep Experience. Broad Resources.

AFFHOLDER is ready for your most challenging underground projects. Having managed many multi-million dollar complex projects, our tunneling teams bring years of hands-on experience and a broad range of technologies to solve every challenge. Our large-diameter tunnel expertise makes us the right choice for a range of sewer line, water line or storm drain installations as well as projects outside the scope of auger-boring or conventional open-trench construction. And we’ll work with you literally every foot of the way to minimize the impact on your business, community, and environment.

  • Soft-Ground Tunneling: Made up of various mixtures of clay, silt or sand, soft-ground ranges in consistency from “firm” to “running.” In these conditions, Affholder can implement a variety of solutions including hand mining, slurry pressure balance tunnel-boring machines, and earth pressure balance machines. Soft-ground methods are suitable for tunneling for sanitary and storm sewers and highway, mass transit, utility, and pedestrian tunnels.

  • Soft-Rock and Hard-Rock Tunneling: Soft rock comes in many forms, including varieties of mudstone, siltstone, sandstone and shale while common types of hard rock include granite and limestone. When faced with hard or soft rock, Affholder employs drill-and-blast and open main beam methods, plus single shield and double shield tunnel- boring machines. Applications include construction of sanitary and storm sewers, and water, highway, mass transit, utility and pedestrian tunnels.

  • Hand-Mined Tunneling: Using liner plate, rib-and-board and timber sets to support the soil or rock, Affholder has successfully completed hand-mined tunnels of various shapes and sizes through a range of soil types. Common applications for hand mining include starter tunnels, tail tunnels, utility tunnels, road crossing tunnels, and connecting tunnels for structures.


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