The Alberta Energy Regulator told CNRL on Friday that its application would be denied, after which the company withdrew it.
"We felt it was inappropriate to allow steaming to resume before we've completed the investigation into the leak at the site," said AER spokesman Bob Curran.
Canadian Natural had wanted to steam within a "restricted zone" at its Primrose oilsands project, imposed last spring after an emulsion of bitumen and water was found to be oozing to the surface at four locations.
The AER is still reviewing a separate CNRL application to steam outside of the restricted area, Curran said.
On Thursday, the company said it had finished cleaning up three of four spill sites, with the last set to be completed before the ground thaws.
It said it would aim to resume steaming at Primrose this month or next. Company president Steve Laut said the steam would be pumped at pressures so low that it would be "impossible" for there to be problems.
At Primrose, Canadian Natural pumps steam underground and allows it to soak into the reservoir before drawing the crude to the surface, a process known as high-pressure cyclic steam stimulation, or HPCSS.
Greenpeace campaigner Mike Hudema says he's glad the application had been withdrawn, but wants to see more done.
"The AER now needs to turn down CNRL's other application to re-steam the area just adjacent to the on-going spills. CNRL shouldn't be able to add to and profit from the damage they've done to this region while investigations into the causes are still outstanding," Hudema said.
"The restrictions must remain in place until the AER's investigation into the incident is completed, solutions identified, and the public are able to review the findings," he added.
Meanwhile, Hudema said a much broader safety review of in-situ technology is also needed.
"What these on-going, uncontrollable, nine-month-plus long spills tell us is that there are major safety gaps in information about our understanding of underground tar sands extraction technology that need to be addressed before the government approves any more tar sands in-situ projects."
On Thursday, Laut reiterated the company's view that the Primrose issues are "solvable" and that faulty wellbores are to blame. So far, the regulator has not come to the same conclusion. Following a similar event in 2009, it flagged geologic weaknesses as a potential cause.
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