But, why is it so big? That answer will help you determine if the file can be easily broken up.
If it is big because there are so many lines of data, how about
save to a .csv file
then use the unix split command to break into several smaller files (each containing x number of rows)
Then you email file in ten chunks (or however many), and the user appends file 2 to end of file 1, then appends file 3, etc...