(?m)^[ \t]*({3}[^\n]*?{3}|[^\n]*?\d{1,2}/\d{1,2}/\d{4}[ \t]+\d{1,2}:\d{1,2}:\d{1,2})[ \t]*$
Well, here's something to get you going in the right direction for interpreting this:
(?m)^[\t]*({3}[^\n]*?{3}
somthing followed by 0 or more spaces and tabs at the beginning follored by 3 asterics...