If you read the NR linked to by the OP, the initial report was "prepared in 2010 by Pellegrino and Associates (the “Pellegrino Report”) which was disclosed in a press release disseminated and filed on SEDAR on March 2, 2011."

Assuming that the report was finished the last day of 2010, that would indicate there was about a 3 month delay minimum, before lowly retailers got informed.