Environmental Science & Engineering - www.esemag.com - June 2004
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Pipe bursting wood stave in British Columbia

For the project, Kamloops used the 24-inch diameter Grundocrack Taurus with a specially fabricated 32-inch front expander with cutting blades.
Kamloops Augering Ltd., of Trail, British Columbia, is a trenchless pipe rehab contractor using several trenchless techniques including directional drilling, pipe ramming, auger boring, and pipe bursting. Malcolm Bachand, son of Kamloop’s founder Monte Bachand, recently completed one of the most unique and difficult pipe bursting projects the firm ever attempted.

General contractor Marwest Industries, Ltd. in Trail, contracted Kamloops to replace 700 feet (213 m) of 30-inch (762-mm) wood stave pipe with 30-inch (762-mm) High Density Polyethylene (HDPE). For the project, Bachand would use the 24-inch (610-mm) Grundocrack Taurus pipe bursting tool from TT Technologies, Aurora, Illinois.

Project background
The pipe bursting project was being carried out for Cominco, Ltd., Trail, BC. Cominco is one of the largest integrated zinc and copper producers in the world. As part of a general upgrade and plant rehabilitation project, a water cooling line was earmarked for replacement.

According to Bachand, the burst was especially challenging. He said, “Cominco had a critical cooling line at its facility in British Colombia that had begun to collapse. To add to the problem, the pipe was 700 feet (213 m) long, extremely deep and was below a highly congested area of the plant with buildings, roads and extensive underground infrastructure. The only solution was to pipe burst the entire run. An open cut option was not feasible. The old cooling line was wood stave pipe and in very rough condition. In many places it had collapsed to half its diameter.”

The 700 feet of wood stave pipe was burst and replaced with 30- inch HDPE in just 3 1/2 hours.
The host pipe
Two other factors made this particular pipe bursting job unique: the host pipe and the bursting tool chosen for the project. Wood stave pipe in itself is not unique. The pipe was used extensively throughout North and South America throughout the 1800s. Replacing deteriorated wood stave through pipe bursting, however, is unique.

TT Technologies Pipe Bursting Specialist, Mike Schwager, explained: “Until the Kamloops project, only a small number of wood stave bursting projects were ever attempted and certainly none of this magnitude and diameter. The thing that makes wood stave so difficult to burst is actually steel. Wood stave pipe is usually bound together with steel bands like a wooden barrel or a continuous steel spiral band.”

In order to effectively burst the steel banding the Kamloops crew used a 32-inch (813-mm) diameter front expander equipped with special cutting blades. This expander was crucial to the success of the project. Schwager said, “We don’t run into situations where we need that large of a tool for bursting that often. The majority of the pipe bursting work currently being done can be more efficiently handled by bursting tools from 3 to 18 inches (76 to 457 mm) in diameter.

Prep work
Marwest Industries prepared the entrance pit. The pit was quite extensive because the wood stave line was located 20 feet (6 m) below the surface. In addition the entrance pit needed to be long enough and wide enough to accommodate the 30-inch (762-mm) HDPE product pipe as it was pulled into place during the bursting operation. The 700 feet (213 m) of HDPE was fused on site.

A winch system was set up at the end of the run, in a 54- inch (1372-mm) diameter manhole. Once the bursting was completed, the Kamloops crew planned to remove the front expander from the tool and pull the bursting tool out through the new product pipe.

An example of wood stave pipe. Wood stave was used extensively throughout North and South America in the early 1800s.
The burst
The bursting proceeded without incident. Bursting times averaged 3 to 4 feet (914 to 1219 mm) per minute. Bachand said, “We were very impressed with the performance of the equipment. We excavated one section of the pipe in order to tie in some lateral connections. Other than that, we expected retrieving the 10,000 lb (4535 kg) Taurus pipe bursting tool through the newly installed HDPE to be the most difficult part of the project.”

Once the tool arrived at the exit manhole, the Kamloops crew removed the expander without incident or damage to the manhole. The winch was then moved to the entrance pit and a winch-line was rodded through the new HDPE and attached to the tool. The Taurus was pulled back, through the newly installed pipe, to the entrance pit without a problem. The entire project took a mere eight days to complete.
For more information contact Kamloops Augering Ltd., 250-573-7814 or
TT Technologies, e-mail: info@TTtechnologies.com.

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