When a company requests a trading halt (usually prior to issuing a news release), the company must assure IIROC that its announcement is imminent. The nature of the announcement and the current status of events must also be disclosed to IIROC, so that IIROC can assess the need and timeframe for the trading halt.

A trading halt is normally very temporary – typically lasting less than two hours. The actual length of the trading halt if determined by IIROC, taking into account the significance of the company's announcement and the time required to disseminate the announcement.

Possibly a foreign entity is in part of the equation, and with a large difference in time zones, the tweaking of the details takes longer. Just thinking.

http://www.iiroc.ca/industry/marketmonitoringanalysis/Pages/Trading-Halts-Timely-Disclosure.aspx