Husky oil stock photo from husky.ca website.

Some major questions remain unanswered after Husky Energy submitted its second report to the province in relation to the July 20 oil spill into the North Saskatchewan River.

The cause of the spill, estimated at about 250,000 litres, is not known. It is also not known how long the pipe was leaking before Husky officials arrived on scene to cap it.

During a conference call Friday afternoon, Deputy Minister of the Economy Doug MacKnight said Husky has been given a 30-day extension to complete its report, allowing more time for specialized testing that may provide those answers.

“This is a major piece of scientific and engineering research that has to go on,” he said.

“The pipe is located on a slope and there is a lot of science involved in investigating the metallurgic failure.”

Another more detailed report will be filed by the company no later than Nov. 21.

Meanwhile, Ash Olesen with the Ministry of Environment says clean-up operations have gone very well.

“Effectively we have moved from response to recovery and monitoring over the winter,” he said.

Olesen added, “I am pleased to report that the current estimate of oil recovered is 93 per cent.”

In addition to the Husky investigation into the spill, the provincial government is doing its own comprehensive investigation. Husky is footing the cost the cleanup.