It was in the 1940s. That's an important point. The four big projects date from the 1940s, and the 1950s. Gunnar in Saskatchewan is from the 1950s. Maxwell was in the 1960s. Sydney tar sands was a joint fed-prov from the 1960s as well. These really are legacies before federal regulations were in place, which were intended to stop them.
On May 8th, 2012. See this statement in context.