Cenovus Energy pioneers use of amphibious excavators in world's largest caribou habitat restoration project
All photos of amphibious excavators at work in the Cold Lake oilsands region provided by Cenovus Energy.
A 20-tonne earthmoving machine that floats atop swampland with less impact than a person’s boots is helping Cenovus Energy restore habitat for threatened woodland caribou in northeast Alberta’s oilsands region.
The company is pioneering the use of amphibious tracked hoes or excavators to restore boreal forest land impacted by oil and gas development. The amphibious vehicles are supporting Cenovus's 10-year, $32-million Caribou Habitat Restoration Project, a voluntary initiative aimed at creating the world’s largest caribou habitat restoration project.
“That’s a big challenge for us over the next 10 years. And we want to find ways to do that safely, efficiently, quickly and in a cost-effective fashion,” says Ted Johnson, Cenovus’s group lead for environmental solutions and systems.
“We see amphibious excavators as a very important tool in our toolbox to help us achieve our goals of improving the habitat for woodland caribou in the areas where we operate,” he says. “Cenovus takes the restoration of woodland caribou habitat in Alberta as a very high priority for our company.”
The Cenovus Caribou Habitat Restoration Project is located in the Cold Lake oilsands region where the company operates its Foster Creek steam-assisted gravity drainage oilsands plant. When the project is finished in 2026, the company expects to have completed restoration work within about 3,900 square kilometres of fragmented boreal forest. That’s about five times the area of the city of Calgary, and it’s the largest single area of caribou habitat restoration undertaken by a company anywhere in the world.
Cenovus is using amphibious excavators to restore forest cover to old oil and gas seismic lines and winter access routes for exploration drilling that haven been slow to regenerate naturally during the last 30 years. The machines prepare and mound the soil, which is a standard forestry technique to help to support the growth of trees planted on the sites after treatment. Excavators also add woody debris and bend tree stems into the open pathways.
“These techniques are all designed to support caribou habitat restoration by bringing trees back to these old disturbances, and reducing the usage of those disturbances as wildlife corridors for both predators to caribou (mainly wolves) and also alternate prey (including deer and moose),” Johnson says. Approximately 3,500 kilometres of old seismic lines, access roads and other linear disturbances are to be treated during the 10-year project, with about 4 million tree seedlings planted.
However, the challenge in Alberta’s northern boreal forest is that half of the landscape is some form of muskeg, including swamps, fens and peat bogs. These mostly treed areas with spongy, wet, very soft organic soils don’t support conventional heavy equipment, including earthmovers. “You would sink out of sight,” Johnson says.
Cenovus’s standard approach has been to do restoration work in these areas in the winter, when the ground is frozen enough to support conventional equipment. However, it’s also more difficult in the winter to do soil treatment techniques, because the ground is so hard.
“The amphibious equipment is a tool we’re using to complete that caribou habitat restoration when the ground is not frozen,” Johnson says.
Theoretically, Cenovus could do restoration year-round with the amphibious track hoes. However, the company doesn’t work in the areas from late February until mid-August, which is a restricted activity period because wildlife is at increased stress level. Caribou may be calving and migratory birds nesting, for example.
Still, the amphibious track hoes enable the company to expand the usual 10-week restoration ‘season’ by an additional 30 weeks – more than a three-fold increase in the typical operating season.
Project supported by Canada’s Oil Sands Innovation Alliance
Johnson got the idea of using amphibious equipment for caribou habitat restoration work after seeing an amphibious track hoe driving on the highway in southern Alberta. After discussing the possibility with Cenovus’s forestry experts and other environmental professionals, the company took the idea to Canada’s Oil Sands Innovation Alliance (COSIA) which approved it as a COSIA joint industry project, funded by Cenovus, ConocoPhillips Canada and Devon Canada.
In November 2015, Cenovus conducted its first pilot with a five-tonne amphibious track hoe – brought to Alberta from Louisiana where it was working in the bayou – and a 20-tonne unit, to see if they could safely work in the swampy boreal forest environment and effectively perform the required restoration techniques. “At the conclusion of that pilot, we felt that, yes [the technology] could work safely in that area and it could complete all of the required forestry techniques we need to do,” Johnson says.
Between the late summer and early fall of 2016, Cenovus did a larger deployment of the amphibious track hoes, including a new excavator custom-built for the restoration project in Alberta. During this large-scale trial, Cenovus managed to complete about 25 per cent of its annual restoration program, treating more than 50 kilometres of seismic lines.
This large-scale operational trial, which included support from Nexen Energy in addition to the COSIA partners involved in the earlier pilot, also evaluated alternative restoration techniques. These included mounting a tree spade on the amphibious track hoe where the bucket would normally be, to enable transplanting of live trees. Also assessed were implements that can be dragged across the soil surface to create surface roughness to increase survival of planted trees and encourage natural regeneration. If successful, these dragged implements may be much faster than current soil mounding techniques.
Cenovus presented the findings of the project and provided the documentation to all 13 COSIA member companies, including at the vice-president level. “Any COSIA member could start to use amphibious equipment if it fits [their operations],” Johnson says.
Johnson is not able to say what the COSIA project cost, because it is confidential among the COSIA partners involved in the project. “I can tell you that it is a financially efficient way of doing our treatment activities in that we’re able to treat the ground at about twice the rate we would in the winter, and we’re able to do that at a lower cost and potentially at a higher effectiveness level, too.”
Machines can drive on land, muskeg, water
The amphibious track hoes look similar to conventional excavators used in large earthworks projects such as road, residential and commercial construction. The difference is that amphibious track hoes can drive on land, muskeg and even water. They’re equipped with an extra-large undercarriage of steel air-filled chambers, similar to pontoons.
The chambers provide enough water displacement or buoyancy to keep the heavy equipment floating atop a marshy surface. “Quite literally, if you were to step on the ground and then have potentially a 20-tonne excavator roll by, your footprint in that marsh would be deeper than the tracked equipment’s footprint would be,” Johnson says.
Cenovus has contracted three different amphibious excavators, ranging in size from 20 tonnes to five tonnes, and all focused on caribou habitat restoration work. “We have crossed a good-sized beaver pond and they floated, no problem – both the 20-tonne and the five-tonne excavators.”
Johnson says the machines “treat the ground very quickly. We are able to create our soil treatment at about twice the kilometres per day than we would do in the winter.” The costs are between 50 to 75 per cent of what they would be in dollars-per-kilometre for the typical winter operating season, he adds.
Although the amphibious track hoes treat the ground quickly, the machines move more slowly on the ground from site to site than a conventional excavator, he says. That presents a logistical challenge in remote areas where there are no ice roads or even oil and gas exploration roads to get equipment operators and fuel in and out of sites. “We’re going to continue to work on it. We’re improving on it,” Johnson says.
Some mining companies have used amphibious excavators including on tailings ponds, but Johnson isn’t aware of other oilsands companies besides Cenovus yet using the machines for restoration work. Much of the restoration work completed to date has been done by local First Nations contracting companies.
Cenovus’s initial monitoring from previous habitat restoration pilot projects using traditional forestry equipment shows reduced wolf and caribou movement and improved tree growth in treated areas. These pilots predated the Caribou Restoration Project announced in 2016. The Cold Lake caribou herd is estimated at 150 animals with declining numbers. Cenovus plans to continue collecting data on vegetation growth as well as moose, bear, caribou and wolf movements to assess the 10-year restoration’s project overall impact.
Click here to view a video of the amphibious excavators.