Skip to Content
District Energy System

DES Tunneling Project Photos from the 1980s


These 1980s photos provide a great perspective on the magnitude of the tunneling project required to install steam and chilled water lines to supply the entire district energy system services area.

Tunnel Bored

The tunnel was bored by a Jarva machine, made in Germany, powered by 3-150 horsepower, 480 volt electric motors. The 14 satellite-shaped cutting teeth are 15 inches in diameter, mounted on an eight-and-a-half foot diameter cutting head. The machine propelled itself by legs which pressed against the side of the completed bore with 1,800,000 pounds of thrust (600,000 pounds of forward thrust). The rock cuttings were fed through the center of the header and conveyed to small gondola cars on a two-foot gauge rail track.

Photo compliments of HL Hailey Co.

Tunnel Shaft Dug 4th Ave

The tunnel was dug by first opening a shaft on 4th Avenue between Commerce and Broadway down to the level of the tunnel (about 40 feet), this is now Manhole 17. The drill machine was put in the shaft and drilled north to Deadrick Street. The machine was brought back to Manhole 17, lifted out and reversed to drill back to Broadway. A second shaft was dug on Broadway between 1st and 2nd Avenues (Manhole 18), the machine was put in and it drilled up Broadway to 7th Avenue. December 1985, Broadway shaft.

Tunnel Shaft Dug 7th Avenue

Another shaft was dug on 7th Avenue and the machine drilled up 7th to Union Street (Manhole 23). A tunnel was dug manually from the 7th Avenue shaft to intercept with the Broadway tunnel. Boring began on January 20th, 1986 and lasted about 2 to 3 weeks.

Tunnel Spoil

The spoil from the Jarva machine was conveyed into these small mine cars and lifted out of the tunnel.

Tunnel Manhole 22

Manhole 22's shaft after it has been concreted. After the piping is installed there will be no room for a golf cart, you'll have to hike it. May 1985, the tunnel was completed in two phases. The first 1983 expansion was to bore the tunnel only up Broadway to 4th Avenue and then up to 4th Avenue. The second phase, or 1985 expansion went up to 7th Avenue and north up 7th. Pilot tunnels had to be dug before the tunneling machine could take over, these pilot tunnels and the shafts had to be done by drilling and blasting.


Regular tunnel inspections are made to keep on top of problems. But because of the nature of our business, when repairs have to be made, someone is either going to be without heating or cooling for a while. Here Chuck Tucker is inspecting the tunnel.