The  original  Trans  Mountain  pipeline  was  built  and  exclusively  used  for about  25  years  to  transport  crude  oil  from  Alberta  to  Kamloops  and  the  lower  mainland  area.  In  the  late  '70's  companies  started  to  batch  refined  product  from  Edmonton  because  it  was  cheaper  than  continuing  to  operate  the  small  refineries  around  Vancouver.  It  is  likely  that  some  crude  was  also  exported  to  Washington  state  via  tanker.

Nowadays  it  does  mostly  ship  refined  product  but  it  does  still  ship  crude  as  well.  Most  of  the  increased  capacity  will  be  used  for  crude  oil  transport  but  it  will  continue  to  transport  refined  products  as  well.