Last checked at 
HOUSTON, Dec 17 (Reuters) - Operators at BP Plc's 405,000 barrel per day (bpd) Whiting, Indiana, refinerycontinued to prep a new 102,000 bpd coking unit for regularproduction on Tuesday, according to sources familiar withoperations at the refinery.
A switch to the planned cheaper heavy crude oil slate hasnot begun, the sources said, contrary to a report by energyindustry intelligence service Genscape. That switch is scheduledfor the first quarter of 2014.
The coker is the last unit to come into production at thesuburban Chicago refinery as part of a $4 billion revamp toswitch the plant's primary crude feed to cheaper oil fromCanada's tar sands oilfields in Alberta.
The refinery's intake of Canadian crude is expected to jumpfrom 85,000 bpd to 350,000 bpd.
A BP spokesman declined to discuss operations at therefinery.
In October, BP said the Whiting refinery would switch toCanadian crude oil at the refinery in the first quarter of 2014.
A coker boosts the amount of refinable material taken from abarrel of crude oil. It also converts residual crude oil intopetroleum coke, which can be used as a coal substitute. (Reporting by Erwin Seba)
