Carlton Tunnel Rehab

The rich history of Colorado’s Carlton Tunnel, originally known as the Busk Ivanhoe Tunnel, spans over 130 years. Although initially constructed for rail access in the late 19th century, it has served various purposes for vehicular transit and water conveyance (the latter being its current operations under the Busk Ivanhoe Water System Authority).  The existing tunnel is 16’ wide by 12’ high, supported by timber sets and bare rock. Many of the timber sets and associated blocking have degraded since installation, resulting in substantial raveling and caving in many areas of the tunnel. While there have been several repairs throughout the decades, substantial obstructions have affected water flow through the tunnel’s 36″ concrete pipe. 

Drill Tech is performing ongoing tunnel rehabilitation (850 LF to date in the 9,500 LF tunnel) to establish safe access to the multiple cave-ins affecting the conveyance pipe and has encountered portions of the collapsed tunnel reaching over 30′ in height.  Once the cave-ins are safely reached, debris is removed to restore flow in the pipe, which is to be replaced with a new HDPE pipe. Drill Tech provided Early Contractor Involvement recommendations to the design and construction phase services, and this project has remained a collaborative effort between the owner, engineers, and Drill Tech services.

At nearly 11,000′ elevation, with the closest paved road being 14 miles away, the remote location of this project has presented logistical challenges of access that require careful coordination of the team as materials are ferried up to the jobsite. The goal of this project is to ultimately increase water capacity and re-establish the tunnel’s ability to safely support traversing service vehicles. 

Leadville, CO

Contract Value:

$12.6M

Delivery Method:

Early Contractor Involvement/Time and Material

Property Owner:

Busk Ivanhoe Water System Authority

General Contractor:

Flatiron

Project Overview

  • 850 LF to date Tunnel Rehabilitation, ongoing in 9,500 LF tunnel
    • Steel Sets
    • New Tunnel Lining
      • V-Deck Lagging
      • Concrete Backfill
    • Rock Bolts
    • Shotcrete
  • Portal Work
    • Debris Removal
    • Scaling
    • Rockfall Mesh
    • Rock Bolts
  • Concrete Pipe Replacement
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