What started out as an experiment in 2011 has proven its value in more ways than one.
The new Tremie device was designed and built by the Operations division and will ultimately save Syncrude millions, while also improving its environmental performance on reclamation and closure of tailings ponds.
It all started with the need to reinvent how Composite Tailings (CT) – which combines fluid fine tailings with gypsum and sand to create a mixture that is deposited in mined-out areas where the tailings release water and quickly settle – was being used in reclamation. However, an even bigger question was whether the CT could be deposited underwater using Tremie technology.
With the assistance of consultants, Syncrude’s Research and Development team designed the first of two Tremie devices based on what other industries, like the concrete sector, use to build – or deposit – materials underwater. A key advantage of using a Tremie device is the ability to create uplands by initially placing material underwater. Essentially the landform is built from the bottom up, which is a significant development for Syncrude’s future reclamation and closure initiatives. On top of that, as CT is deposited, water is released from the deposit and recycled back into the extraction process which improves Syncrude’s water efficiency.
In order to understand the optimum Tremie deposition technique, two types of devices were built:
- The first design, fabricated by Research and Development, was a barge-based Tremie diffuser;
- The second was a compact end-of-pipe Tremie built by Operations.
The intent was to test both over a period of time to understand which depositional technique was better.
The test trial began in 2012 and two years later Syncrude’s Research and Development department had collected enough evidence to prove that the smaller device performed just as effectively as the larger version. In 2014, the industrial-sized model was officially decommissioned.
“Not only can this Syncrude-engineered device be moved around to different locations, the new, smaller design will save us millions of dollars for years to come and establish underwater landforms that will help our reclamation efforts,” said Jim Lorentz, Leader, Syncrude R&D Tailings Technology.