Canada Post has delivered 72 hours notice of a potential lockout, pointing to prolonged negotiations and a rapid decline in mail volume. It could mean postal service grinds to a halt on Friday. The post office maintains it’s last offer, June 25, is fair and reasonable given the economic times; that the union’s proposals are unaffordable. It still hopes to reach a negotiated settlement without the need for a lockout. The Canadian Union of Postal Workers says it’s been showing up at the bargaining table with proposals it says can make the post office more profitable and improve services.