A recent report by the Commission for Environmental Cooperation described "scientifically valid evidence" that Alberta's oil sands tailings ponds are leaking and contaminating groundwater. These methods must be simple, easy to implement, cost effective and have a minimum impact on human health and the environment.
Production of CT with CaSO4 or CO2 additives to prevent segregation remains one of the major technologies to reduce MFT accumulation. Tiny glass-like bubbles developed at the University of Waterloo show a lot of promise for dealing with the most toxic components of oil sands tailings ponds. In the oil sands, tailings are a mixture of water, sand, clay and residual bitumen, and are the by-product of the hot water treatment process used to separate the oil from sand and clay in oil sands mining operations. The mineable surface of the McMurray Formation oil sands deposit in Alberta, for instance, consists of a quartzose, uniform, fine to medium grain sized sand. Oil sands tailings are heterogeneous sources of VOC, CO2, CH4, and RSC emissions.
If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Still, the report notes that recent studies show “strong scientifically valid evidence” of liquid from the ponds seeping into nearby groundwater.
Comments on this story are moderated according to our Submission Guidelines. Welcome to The Globe and Mail’s comment community. Oil sands mining operations produce a toxic brew of water, sand, silt and petrochemical waste products. Orihel told Quirks & Quarks host Bob McDonald that she and her students tested the titanium dioxide treated water on fathead minnow embryos. Despite at least 15 instances where levels of toxic substances in groundwater exceeded federal guidelines, Environment Canada told the CEC it didn’t pursue violations because it couldn’t prove “beyond reasonable doubt” that the elevated levels were caused by leaking and were not naturally occurring. The storage of large volumes of tailings has become an issue for Canada׳s oil sands industry. In 2017, the commission was asked by two environmental groups and a member of the K’ahsho Got’ine Dene First Nation in the Northwest Territories to look into whether Canada had done enough to investigate seepage from the ponds and if Fisheries Act water protections were being ignored.
The accumulation of mature fine tailings (MFT) in tailings ponds has been a concern of the oil sands industry for nearly four decades. The majority of the fines separate or segregate during tailings sand deposition and flow into the pond in suspension to form fluid fine tailings. Two technology options are being investigated; the use of thickeners to make NST and dewatering MFT by treating it with an organic polymer and CO2. Centrifuging MFT accelerates the release of water from the MFT and produces a soft, clay-rich soil termed “centrifuge cake.” Syncrude Canada proposes to sand cap the resulting centrifuge cake deposit for reclamation as a dry landscape feature. They must also improve the thermal efficiency and produce tailings with acceptable settling and consolidation properties without harming the release water chemistry and fuel quality of bitumen. Methods that capture the spatial and temporal variation of emissions are needed. The water containing these chemicals is toxic to animals, particularly aquatic organisms. Although it says there’s inconclusive evidence of oilsands residue in the river itself, there are “indications” it has reached river sediments. “If we do find evidence of a violation in the Fisheries Act, we will take appropriate action,” he said.
Efforts are being made to reduce the impact that tailings ponds have on the environment. The report found a lack of communication and resource-sharing between Ottawa and Alberta, noting the two regulatory systems overlap only when it comes to joint environmental reviews for new oil sands facilities.
He said the enforcement branch will be taking more water samples this fall. Gu's technology consists of tiny glass bubbles coated with titanium dioxide nanocrystals that can float on the surface of the tailings ponds.