While the word gondola conjures images of skier-filled cable cars ascending breathtaking slopes, in the spectacular terrain along TransCanada’s Tamazunchale Extension Pipeline Project, this is not the case. Here, a state-of-the art construction gondola transports tons of steel pipe and construction materials, not people. This gondola technology is helping crews conquer the steep, difficult slope they’ve affectionately dubbed, “Waterloo”.
“It’s not an easy operation, but this is a proven technology around the world in the pipeline construction business.”
— Alejandro Iriarte, TransCanada Project Director, Pipelines, Mexico Projects
Iriarte is overseeing the Tamazunchale Extension, a 230-km (143-mile) natural gas pipeline that traverses some of Mexico’s most mountainous terrain. And this specific location along the route is particularly challenging; it’s extremely rugged and in places rises at a 50-degree angle, making traditional slope installation practices onerous and slow. To surmount the challenging terrain, the project’s engineering procurement construction contractor, GDI SICIM Pipelines (GSP), suggested the use of gondola technology.
Operators control the gondola remotely to safely hoist loads of up to eight tonnes up along the slope. Once the pipe is installed, welded and secured, the cable crane will be used for the final stage of project work, including the installation of geotechnical structures to ensure the pipeline can operate safely and reliably throughout the life of the project.
“Installation using any other option, would have taken significantly longer on this slope and with higher safety hazard exposure,” says Iriarte, who also oversaw the use of microtunneling technology through another difficult section of the Tamazunchale Extension. For that particular section, a microtunnel was suggested by GSP as a more effective option than traditional open-trench or horizontal directional drilling (HDD).
“No other technology would offer the same pipeline integrity as the microtunnel for long-term operations.”
— Andrew Jenkins, TransCanada VP, Mexico Projects
“Construction was subcontracted to I.CO.P, an Italian company experienced at building microtunnels in mountainous terrains,” Jenkins adds.
The tunnel, which runs about 672 metres (734 yards) through a mountain, was drilled using a remote-controlled tunnel-boring machine (TBM) and pipe-jacking system. The TBM advanced through the mountain using a rotating cutting head to carve an eight-foot diameter tunnel through to the other side. Behind the device, concrete liners were jacked into place to maintain the tunnel’s integrity before the pipeline was moved into place.
When the TBM broke through the designated exit location for the microtunnel in late 2013, construction workers and TransCanada employees were on site to celebrate the success of Mexico’s first pipeline microtunnel.
“The completed microtunnel will serve to commemorate innovative engineering in areas with steep and unstable slopes, or places where the open-trench technique may be considered unsafe and impractical,” says Iriarte.
Next up for TransCanada is pipeline installation down a cliff along a rugged stretch of the Topolobampo Project, a 530-km (329-mile) natural gas pipeline currently under construction in Mexico. This installation process will utilize vertical-drilling technologies from the mining, exploration and hydroelectricity industries.
“The new technology will use a combination of directional drilling and tunneling,” says Jenkins. “What this involves is drilling a vertical pilot hole from the top of the cliff then excavating a tunnel at the bottom of the mountain to intersect the pilot hole.”
The pilot hole is expanded by pulling a reaming tool up through the vertical hole and using the tool to enlarge the pilot hole to the required diameter. Debris from the drilling process lands in the tunnel and is removed by machinery. This process eliminates the need for drilling fluid necessary in conventional HDD procedures.
While these technologies have been globally tried and tested, their integration is fairly new to TransCanada and could become a more commonly used practice for proposed pipeline projects in the rugged slopes of British Columbia, Canada, such as Coastal GasLink and Prince Rupert Gas Transmission.
“These Mexico projects have directly applicable terrain to the conditions in British Columbia,” says Jenkins, adding that pipelines are the safest way to transport the oil and gas that North America and Mexico needs to meet their daily demand for energy. “There’s no increased risk to the technology we’re using for these pipelines, but it is industry-leading stuff in North America.”
Innovation has always been key to TransCanada’s success, with a track record of more than 60 years dedicated to cutting-edge technological advancement and a history of investment into research and development.